CN107994770A - Single-stage current type converter with series multistage switch L.C. network - Google Patents

Abstract

A single-stage current-mode converter circuit structure with a series multi-stage switch inductance network, which is composed of an input DC power supply or a single-phase AC power supply, a high-frequency combined modulation switch, a capacitor filter, a DC load or a single-phase AC load in sequence It is composed of cascading, and a multi-level switch inductance network is connected in series between the input power supply and the high-frequency combined modulation switch; the multi-level switch inductance network is composed of energy storage inductors and n identical SLCS type two-ports cascaded in sequence The switch-sensing-capacitance network unit is cascaded, where n is a natural number greater than 1; each SLCS two-port switch-sensing-capacitance network unit is composed of two power diodes or two four-quadrant power switches, an energy storage inductor, and a storage The high-frequency combined modulation switch is composed of a power diode, a two-quadrant power switch or a four-quadrant power switch. This kind of converter can convert unstable wide-range low-voltage direct current or single-phase alternating current into stable, high-quality direct current or single-phase sinusoidal alternating current with high efficiency in a single stage.

Description

Single-stage current-mode converter with series-connected multi-stage switch-capacitance network

technical field

The invention relates to a single-stage current-type converter with a series-connected multi-stage switch inductance network, which belongs to the technology of power electronics.

Background technique

A converter is a static converter device that uses power semiconductor devices to convert direct current or alternating current into direct current or alternating current for use with direct current loads or alternating current loads (including grid-connected power generation with an alternating current grid).

Due to the increasing shortage of fossil energy (non-renewable energy) such as oil, coal and natural gas, serious environmental pollution, global warming, nuclear waste and environmental pollution caused by nuclear energy production, energy and the environment have become major issues facing mankind in the 21st century. . Renewable energy (green energy) such as solar energy, wind energy, hydrogen energy, tidal energy, and geothermal energy has the advantages of clean, pollution-free, cheap, reliable, and abundant. People pay more and more attention to its development and utilization. Sustained economic development is of great significance. The DC power converted from renewable energy such as solar energy, hydrogen energy, tidal energy, and geothermal energy is usually unstable, and a DC-DC converter is required to convert it into another DC power for the load; the conversion of renewable energy such as wind energy The AC power is usually AC with variable voltage and frequency, which requires an AC-DC converter to convert it into DC power for loads (such as inverter loads); unstable AC power generated by primary power sources such as alternators requires the use of AC - The AC converter converts it into AC power with the same frequency and constant voltage to supply the AC load. DC converters, rectifiers and AC converters have broad application prospects in DC generators, batteries, solar cells, fuel cells, wind turbines, AC generators, etc., where DC and AC power sources are converted.

At present, DC-DC, AC-DC, AC-AC conversion occasions usually adopt the traditional PWM converter circuit structure, there are bridge arm power devices that need to set dead zones or overlap time, low reliability and output waveform quality, and insufficient boost ratio Large (non-isolated), large volume and weight of the system, and high cost (input or output plus single-phase power frequency transformer) and other defects.

Therefore, it is imminent to seek a new type of single-stage current-mode converter with series-connected multi-stage switch-sensing-capacitance network, which does not require dead time in the bridge arm, has high reliability, and has a single-stage circuit structure. This is to effectively overcome the shortcomings of traditional PWM converters such as the dead time of the bridge arm, the boost ratio is not large enough (non-isolated), the volume and weight of the system, and the high cost (input or output plus single-phase power frequency transformer) and other defects. , improve the output waveform quality and reliability of the conversion system and reduce the EMI on the input side, broaden the theory of power electronics conversion technology and renewable energy power generation technology, promote the development of new energy power generation industry and develop an energy-saving and conservation-oriented society. significance.

Contents of the invention

The purpose of the present invention is to provide a multi-connection transformer with the characteristics of large step-up ratio, single-stage power conversion, high power density, high conversion efficiency, high output waveform quality, high reliability, wide input voltage variation range, and low cost. A single-stage current-mode converter with a switched inductive network.

The technical solution 1 of the present invention is: a single-stage current-mode converter with a multi-stage switch inductance network connected in series, which is composed of an input DC power supply, a high-frequency combined modulation switch, a capacitor filter and a DC load sequentially cascaded, And between the input DC power supply and the high-frequency combined modulation switch, there is a multi-level switch inductance network in series; the multi-level switch inductance network is composed of energy storage inductance L ₀ and n identical SLCS type cascaded in sequence Two-port switch-inductive-capacitive network units are cascaded, where n is a natural number greater than 1; each SLCS-type two-port switch-inductive-capacitive network unit is composed of two power diodes S _j and S _j ', and an energy storage inductance L _j , an energy storage capacitor C _j , the cathode of the power diode S _j is connected to one end of the energy storage inductor L _j , and the positive terminal of the energy storage capacitor C _j , and the anode of the power diode S _j is connected to the other end of the energy storage inductor L _j One end is respectively connected to the anode and cathode of the power diode S _j ′, the negative polarity end of the energy storage capacitor C _j is connected to the positive polarity end of the energy storage capacitor at the same position in the adjacent pre-stage SLCS type two-port switch inductive network unit The connection between power diode S _j and power diode S _j ′ and the negative terminal of energy storage capacitor C _j form the input port of the jth SLCS type two-port switch inductive network unit, and the energy storage inductance L _j and The connection end of the power diode S _j ′ and the positive polarity end of the energy storage capacitor C _j constitute the output port of the jth SLCS type two-port switch inductive network unit, and the positive polarity of the input DC power supply and the negative polarity of the energy storage capacitor C ₁ An energy storage inductance L ₀ is connected between the connecting end and the connecting end of the power diode S ₁ and the power diode S ₁ ′, wherein j is a natural number not greater than n; the high-frequency combination modulation switch is composed of a Stress, bidirectional current stress two-quadrant power switch S ₁ "and a power diode S ₂ ", the drain or collector of the two-quadrant power switch S ₁ ", the anode of the power diode S ₂ "and the power diode S _n ' The cathode is connected to the connection terminal of the energy storage inductor L _n , the source or emitter of the two-quadrant power switch S ₁ "is connected to the negative terminal of the input DC power supply and the negative terminal of the output filter capacitor, and the power diode S ₂ " The cathode is connected to the positive terminal of the output filter capacitor.

The technical solution 2 of the present invention is: a single-stage current-type converter with a series multi-stage switch inductance network, which is composed of an input single-phase AC power supply, a single-phase high-frequency combination modulation switch, a capacitor filter and a DC load in sequence Cascaded configuration, and between the input single-phase AC power supply and the single-phase high-frequency combined modulation switch, there are multiple levels of switch inductance network connected in series; the multi-level switch inductance network is composed of energy storage inductance _L The cascade connection of n identical SLCS-type two-port switch-capacitive network units is formed, where n is a natural number greater than 1; each SLCS-type two-port switch-capacitor network unit is composed of two four-quadrant power switches S _j and S _j ′, an energy storage inductance L _j , and an energy storage capacitor C _j , one end of the four-quadrant power switch S _j is connected with one end of the energy storage inductance L _j , and the reference positive terminal of the energy storage capacitor C _j , four The other end of the quadrant power switch S _j and the other end of the energy storage inductor L _j are respectively connected to the two ends of the four-quadrant power switch S _j ′, and the reference negative end of the energy storage capacitor C _j is connected to the adjacent front-end SLCS type The reference positive terminal of the energy storage capacitor at the same position in the two-port switch inductive network unit is connected, and the connection terminal of the four-quadrant power switch S _j and S _j ' and the reference negative terminal of the energy storage capacitor C _j constitute the jth The input port of a SLCS two-port switch inductive network unit, the connection end of the energy storage inductor L _j and the four-quadrant power switch S _j ′, and the reference positive terminal of the energy storage capacitor C _j constitute the jth SLCS two-port The output port of the switch inductive network unit is connected between the connection terminal of the input single-phase AC power reference positive polarity and the reference negative polarity of the energy storage capacitor _C1 and the connection terminal of the four-quadrant power switch _S1 and the four-quadrant power switch S1 _′ There is an energy storage inductance L ₀ , wherein j is a natural number not greater than n; the single-phase high-frequency combined modulation switch is a single-phase full bridge composed of four two-quadrant power switches that bear unidirectional voltage stress and bidirectional current stress Pulse width modulation rectifier circuit.

The technical solution 3 of the present invention is: a single-stage current-type converter with a series multi-stage switch inductive network, which is composed of an input single-phase AC power supply, a single-phase high-frequency combination modulation switch, a single-phase capacitor filter and a single-phase The AC load is cascaded in sequence, and a multi-level switch inductance network is connected in series between the input single-phase AC power supply and the single-phase high-frequency combined modulation switch; the multi-level switch inductance network is formed by the energy storage inductance L ₀ It is composed of n identical SLCS two-port switch inductive network units cascaded in sequence, where n is a natural number greater than 1; each SLCS two-port switch inductive network unit is composed of two four-quadrant power Switches S _j and S _j ′, an energy storage inductance L _j , and an energy storage capacitor C _j constitute one end of the four-quadrant power switch S _j , one end of the energy storage inductance L _j , and the reference positive terminal of the energy storage capacitor C _j The other end of the four-quadrant power switch S _j and the other end of the energy storage inductor L _j are respectively connected to the two ends of the four-quadrant power switch S _j ', and the reference negative end of the energy storage capacitor C _j is connected to the adjacent The reference positive terminal of the energy storage capacitor at the same position in the front-end SLCS type two-port switch inductive network unit is connected, and the connection terminal of the four-quadrant power switch S _j and S _j ' is connected to the reference negative polarity terminal of the energy storage capacitor C _j It constitutes the input port of the jth SLCS type two-port switch inductive network unit, the connection end of the energy storage inductor L _j and the four-quadrant power switch S _j ′ and the reference positive terminal of the energy storage capacitor C _j constitute the jth The output port of the SLCS type two-port switch inductive network unit is connected between the connection end of the input single-phase AC power reference positive polarity and the connection end of the energy storage capacitor C ₁ reference negative polarity and the connection end of the four-quadrant power switch S ₁ and S ₁ ′ There is an energy storage inductance L ₀ , wherein j is a natural number not greater than n; the single-phase high-frequency combined modulation switch is composed of two four-quadrant power switches that bear bidirectional voltage stress and bidirectional current stress, and the four-quadrant power switch S One end of ₁ ″ and S ₂ ″ is connected to the connection end of the energy storage inductance L _n and the four-quadrant power switch S _n ′, and the other end of the four-quadrant power switch S ₁ ″ is connected to the input single-phase AC power supply and the single-phase output filter capacitor The reference negative terminal of the four-quadrant power switch S ₂ "is connected to the reference positive terminal of the single-phase output filter capacitor.

In the present invention, the traditional single-stage (single-phase) PWM converter circuit structure or multi-stage cascaded circuit structure composed of (single-phase) high-frequency combined modulation switch, (single-phase) filter, (single-phase power frequency transformer) cascaded The PWM converter circuit structure is constructed as a "single-stage circuit structure composed of a multi-stage switch inductive network and a sequentially cascaded (single-phase) high-frequency combination modulation switch, and a (single-phase) filter." A new concept and circuit structure of a single-stage current-mode converter with a series multi-stage switch inductive network, that is, by providing n identical SLCS-type two-port switch-inductive network units cascaded in sequence, using the previous SLCS-type two-port The output of the switch inductive network unit is used as the input of the subsequent SLCS type two-port switch inductive network unit to increase the boost ratio of the converter. The adjustment of the boost ratio of the converter is realized by adjusting the number of stages n of the SLCS type two-port switch inductance network unit and the magnetization duty cycle of the converter energy storage inductance D ₀ =T ₀ /T _S , where T _S is high T ₀ is the conduction time (for DC-DC, AC-AC conversion) of the (single-phase) high-frequency combined modulation switch within one T _S , and the common conduction time of the lower bridge arm or the upper bridge arm ( For AC-DC conversion).

The advantage of the present invention is that the present invention can single-stage transform unstable wide-range low-voltage direct current or single-phase alternating current into stable, high-quality direct current or single-phase sinusoidal alternating current, and has single-stage power conversion, high power density, and high conversion efficiency , large step-up ratio, high output waveform quality, high reliability, low cost and other advantages, suitable for DC-DC, AC-DC and AC-AC power conversion occasions.

Description of drawings

Figure 1. Circuit structure of a single-stage current-mode dc-dc converter with a series-connected multi-stage switched inductive network.

Figure 2. Schematic waveforms of a single-stage current-mode DC-DC converter with a series-connected multi-stage switched inductive network.

Figure 3. An example circuit topology of a single-stage current-mode DC-DC converter with a series-connected multi-stage switched-capacitance network.

Fig. 4. The magnetization equivalent circuit of D ₀ T _S of the energy storage inductor of a single-stage current-mode DC-DC converter with a series multi-stage switch inductance network during the conduction period of the high-frequency combined modulation switch.

Figure 5. The demagnetization equivalent circuit of the energy storage inductor of a single-stage current-mode DC-DC converter with a series multi-stage switch inductance network during the high-frequency combined modulation switch cut-off period (1-D ₀ ) T _S.

Figure 6. Block diagram of the control principle of a single-stage current-mode DC-DC converter with a series-connected multi-stage switch-capacitance network.

Figure 7. Control principle waveforms of a single-stage current-mode DC-DC converter with a series-connected multi-stage switched inductive network.

Figure 8. Circuit structure of a single-stage current-mode AC-DC converter with a series-connected multi-stage switch-capacitance network.

Figure 9. Schematic waveforms of a single-stage current-mode AC-DC converter with a series-connected multi-stage switched inductive network.

Figure 10. Example circuit topology of a single-stage current-mode AC-DC converter with a series-connected multi-stage switched-capacitance network.

Figure 11. The magnetization equivalent circuit of the energy storage inductor of a single-stage current-mode AC-DC converter with a series multi-stage switch inductance network during the conduction period of the lower bridge arm D ₀ T _S and the positive half cycle of the input voltage.

Figure 12. The demagnetization equivalent of the energy storage inductor of a single-stage current-mode AC-DC converter with a series multi-stage switch inductance network during the cross-conduction period of the bridge arm (1-D ₀ )T _S and the positive half cycle of the input voltage circuit.

Figure 13. The magnetization equivalent circuit of the energy storage inductor of a single-stage current-mode AC-DC converter with a series multi-stage switch inductance network during the conduction period of the lower bridge arm D ₀ T _S and the negative half cycle of the input voltage.

Figure 14. The demagnetization equivalent of the energy storage inductor of a single-stage current-mode AC-DC converter with a series multi-stage switch inductance network during the cross-conduction period of the bridge arm (1-D ₀ )T _S and the negative half cycle of the input voltage circuit.

Figure 15. Block diagram of the control principle of a single-stage current-mode AC-DC converter with a series-connected multi-stage switched inductive network.

Figure 16. Control principle waveforms of a single-stage current-mode AC-DC converter with a series-connected multi-stage switched-capacitance network.

Figure 17. Circuit structure of a single-stage current-mode AC-AC converter with a series-connected multi-stage switch-capacitance network.

Figure 18. Schematic waveforms of a single-stage current-mode AC-AC converter with a series-connected multi-stage switched-capacitance network.

Figure 19. Example circuit topology of a single-stage current-mode AC-AC converter with a series-connected multi-stage switch-capacitance network.

Figure 20. The magnetization equivalent circuit of the energy storage inductor of a single-stage current-mode AC-AC converter with a series multi-stage switch inductance network during the conduction period of the high-frequency combined modulation switch D _{0 TS} and the positive half cycle of the input voltage.

Figure 21. The demagnetization of the energy storage inductor of a single-stage current-mode AC-AC converter with a series multi-stage switch inductance network during the cut-off period of the high-frequency combined modulation switch (1-D ₀ )T _S and the positive half cycle of the input voltage effective circuit.

Figure 22. The magnetization equivalent circuit of the energy storage inductor of a single-stage current-mode AC-AC converter with a series multi-stage switch inductance network during the conduction period of the high-frequency combined modulation switch D _{0 TS} and the negative half cycle of the input voltage.

Figure 23. The demagnetization of the energy storage inductor of a single-stage current-mode AC-AC converter with a series multi-stage switch inductance network during the high-frequency combined modulation switch cut-off period (1-D ₀ )T _S and the negative half cycle of the input voltage, etc. effective circuit.

Figure 24. Control block diagram of a single-stage current-mode AC-AC converter with a series-connected multi-stage switch-capacitance network.

Figure 25. Control principle waveforms of a single-stage current-mode AC-AC converter with a series-connected multi-stage switch-capacitance network.

Detailed ways:

The technical solution 1 of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

A single-stage current-mode DC-DC converter with a series multi-stage switch inductive network is composed of an input DC power supply, a high-frequency combined modulation switch, a capacitor filter and a DC load in sequence, and is connected between the input DC power supply and the high A multi-stage switch inductance network is connected in series between the frequency combination modulation switches; the multi-stage switch inductance network is composed of energy storage inductance L ₀ and n identical SLCS type two-port switch inductance network units cascaded in sequence Cascade structure, where n is a natural number greater than 1; each SLCS two-port switch inductive network unit is composed of two power diodes S _j and S _j ′, an energy storage inductor L _j , and an energy storage capacitor C _j The cathode of the power diode S _j is connected to one end of the energy storage inductor L _j and the positive end of the energy storage capacitor C _j , and the anode of the power diode S _j and the other end of the energy storage inductor L _j are respectively connected to the power diode S _j ′ is connected to the anode and cathode, the negative terminal of the energy storage capacitor C _j is connected to the positive terminal of the energy storage capacitor at the same position in the adjacent front-stage SLCS type two-port switch inductive network unit, and the power diode S _j The connection terminal with the power diode S _j ' and the negative terminal of the energy storage capacitor C _j form the input port of the jth SLCS type two-port switch inductive network unit, and the connection between the energy storage inductance L _j and the power diode S _j ' The terminal and the positive terminal of the energy storage capacitor C _j form the output port of the jth SLCS type two-port switch inductive network unit, and the connection terminal between the positive polarity of the input DC power supply and the negative polarity of the energy storage capacitor C ₁ and the power diode S ₁ There is an energy storage inductance L ₀ connected to the connection end of the power diode S ₁ ′, where j is a natural number not greater than n; the high-frequency combined modulation switch is composed of two The quadrant power switch S ₁ ″ and a power diode S ₂ ″ are composed of the drain or collector of the two-quadrant power switch S ₁ ″, the anode of the power diode S ₂ ″ and the cathode of the power diode S _n ′, and the energy storage inductance L _n The source or emitter of the two-quadrant power switch S ₁ "is connected to the negative terminal of the input DC power supply and the negative terminal of the output filter capacitor, and the cathode of the power diode S ₂ " is connected to the negative terminal of the output filter capacitor. Connect to the positive terminal.

The circuit structure and principle waveform of a single-stage current-mode DC-DC converter with a series-connected multi-stage switch inductance network are shown in Figures 1 and 2, respectively. In Figures 1 and 2, U _i is the input DC voltage, Z _L is the output DC load, U _o and I _o are the output DC voltage and DC current, respectively. The multi-level switch inductance network is composed of energy storage inductance L ₀ and n identical SLCS two-port impedance network units cascaded in sequence, where n is a natural number greater than 1, and each SLCS two-port switch inductance The capacitor network unit is composed of two power diodes S _j and S _j ′, an energy storage inductance L _j , and an energy storage capacitor C _j ; the high-frequency combination modulation switch is composed of a unidirectional voltage stress and bidirectional current stress The two-quadrant power switch S ₁ "and a power diode S ₂ "consists of; the output filter can only be a capacitor filter; the input filter can be set or not set between the input DC power supply U _i and the multi-level switch inductive network, setting When the filter is input, the ripple of the input DC current can be reduced. When the high-frequency combined modulation switch is turned on, the input DC power supply U _i and the energy storage capacitors C ₁ ,...C _n together magnetize the energy storage inductors L ₀ , L ₁ ,...L _n , and the output DC load depends on the output capacitor filter Maintain power supply; when the high-frequency combined modulation switch is cut off, the energy storage inductors L ₀ , L ₁ , ... L _n are demagnetized and together with the input DC power supply U _i , supply power to the energy storage capacitors C ₁ , ... C _n and the output DC load . The multi-level switch inductive network and the high-frequency combined modulation switch modulate the input DC voltage U _i into a high-frequency pulse DC voltage u ₁ , and obtain a smooth DC voltage u ₂ on the output DC load after filtering, that is, the output DC voltage U _o .

The single-stage DC-DC converter of the present invention utilizes n identical SLCS type two-port switch inductive network units cascaded in sequence and the output of the front-stage two-port switch inductive unit is the rear-stage two-port switch The single-stage circuit structure in which the input of the inductance-capacitance unit is used to increase the boost ratio of the converter is essentially different from the traditional single-stage PWM DC-DC converter circuit structure. Therefore, the single-stage DC-DC converter of the present invention is novel and inventive, and has high conversion efficiency (meaning small energy loss), high power density (meaning small volume and weight), and large boost ratio ( It means that the input DC voltage with a wider or lower variation range can be converted into the required output DC voltage), the output voltage ripple is small, the reliability is high, the input voltage configuration is flexible, the cost is low, and the application prospect is wide. An ideal energy-saving and consumption-reducing DC-DC converter has more important value in today's vigorously advocating the construction of an energy-saving and conservation-oriented society.

A circuit topology embodiment of a single-stage current-mode DC-DC converter with a series-connected multi-stage switch inductive capacitor network is shown in FIG. 3 . In Fig. 3, the high-frequency combined modulation switch S ₁ ′ selects a MOSFET device, and may also use IGBT, GTR and other devices. The single-stage DC-DC converter can convert an unstable low-voltage direct current (such as batteries, photovoltaic cells, fuel cells, wind turbines, etc.) Civilian industrial DC power supply (such as communication DC converter and photovoltaic DC converter 24VDC/220VDC, 48VDC/380VDC, 96VDC/380VDC) and defense industry DC power supply (such as aviation DC converter 27VDC/270VDC), etc.

Each energy storage inductance of a single-stage current-mode DC-DC converter with a series multi-stage switch inductance network is magnetized and demagnetized once in a high-frequency switching cycle T _S , and the magnetization period corresponds to a high-frequency combined modulation switch D ₀ T _S during S ₁ 〝on (S ₂ 〝off), and the demagnetization period corresponds to high-frequency combination modulation switch S ₁ 〝off (S ₂ 〝on) period (1-D ₀ )T _S (that is, for during the energy output of the output side). The magnetization equivalent circuit of D ₀ T _S and the high-frequency combined modulation switch S _{1 " off} ( The demagnetization equivalent circuit of (1-D ₀ ) T _S during S ₂ 〞conduction) is shown in Fig. 4 and Fig. 5 respectively. In Figures 4 and 5, the polarity of the output voltage U _o is the reference direction, while the polarity of each current is the actual direction.

It is assumed that the terminal voltage of the energy storage capacitor is constant in a high-frequency switching cycle T _S , represented by U _C1 , U _C2 , . . . , U _Cn . From the magnetization equivalent circuit of D ₀ T _S shown in Figure 4 during the high-frequency combined modulation switch S ₁ ″ on (S ₂ ″ off), the magnetization equivalent circuit can be obtained,

In formula (1.0)-(1.n), n is a natural number greater than 1, and j is a natural number not greater than n. From the demagnetization equivalent circuit of the energy storage inductor shown in Figure 5 during the period (1-D ₀ ) T _S of the high-frequency combined modulation switch S ₁ ″ off (S ₂ ″ on), it can be obtained,

In the formula (2.n), U ₁ is the amplitude of the voltage u 1 of the high-frequency combined modulation switch S ₁ ″ off (S ₂ ″ on) during (1-D ₀ ) T _S voltage u ₁ . According to the state-space averaging method, formula (1)×D ₀ + formula (2)×(1-D ₀ ), let It can be obtained that the energy storage capacitor voltage values U _C1 , U _C2 , ..., U _Cn of the multi-level switch inductive capacitor network are

The amplitude of the voltage u ₁ of the high-frequency combination modulation switch S ₁ "off (S ₂ "on) period (1-D ₀ ) T _S , that is, the voltage U ₂ and the output voltage U _O , namely

Therefore, the voltage transfer ratio of a single-stage current-mode DC-DC converter with a series multi-stage switched inductance network is

It can be seen from formula (5) that the voltage transfer ratio of the single-stage DC-DC converter is greater than 1 at different values of n and D ₀ , and is greater than the voltage transfer ratio D ₀ of the traditional single-stage PWM DC-DC converter ( Buck type), 1/(1-D ₀ ) (Boost type), D ₀ /(1-D ₀ ) (Buck-Boost type); from the energy storage inductor magnetization and demagnetization equivalent shown in Figures 4 and 5 It can be seen from the circuit that the single-stage DC-DC converter belongs to the current mode (Boost type) converter, and in particular, the step-up ratio of the converter can be increased by increasing the value of n. The multi-stage and single-stage in "single-stage current-mode DC-DC converter with series-connected multi-level switch inductive network" refer to "number of stages of switch inductive network" and "number of conversion stages of converter", respectively.

A single-stage current-mode DC-DC converter with a series-connected multi-stage switch inductive network has only a single-stage power conversion link, and its control system needs to realize the control of the output voltage, and it also needs to realize the maximum power point tracking control of the photovoltaic cell when it is powered by the photovoltaic cell MPPT. Therefore, this single-stage DC-DC converter adopts the PWM control strategy of output voltage feedback, as shown in Figures 6 and 7. The output voltage feedback signal _Uof is compared with the reference voltage _Ur , and the signal _Ue is obtained after the error is amplified. After _Ue is intersected with the triangular carrier _uc , the control signal of the high-frequency combined modulation switch _S1 ″ is output. When the input voltage _Ui or When the load Z _L changes, the output voltage U _o can be stabilized by adjusting the conduction duty cycle D _0. Therefore, it is feasible for the single-stage DC-DC converter to adopt the PWM control strategy of output voltage feedback.

The technical solution 2 of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

A single-stage current-mode AC-DC converter with a series multi-stage switch inductive network is composed of an input single-phase AC power supply, a single-phase high-frequency combination modulation switch, a capacitor filter and a DC load in cascaded order, and the input A multi-level switch inductance network is connected in series between the single-phase AC power supply and the single-phase high-frequency combined modulation switch; the multi-level switch inductance network is composed of energy storage inductance L ₀ and n identical SLCSs cascaded in sequence Type two-port switch-sensing-capacitance network units are cascaded, where n is a natural number greater than 1; each SLCS-type two-port switch-sensing-capacitance network unit is composed of two four-quadrant power switches S _j and S _j ′, an energy storage Inductor L _j and an energy storage capacitor C _j are formed. One end of the four-quadrant power switch S _j is connected to one end of the energy storage inductor L _j and the reference positive terminal of the energy storage capacitor C _j . The other end of the four-quadrant power switch S _j One end and the other end of the energy storage inductor L _j are respectively connected to the two ends of the four-quadrant power switch S _j ′, and the reference negative polarity end of the energy storage capacitor C _j is connected to the adjacent front-end SLCS type two-port switch inductive network unit The reference positive terminals of the energy storage capacitors at the same position are connected, the connection terminals of the four-quadrant power switches S _j and S _j ′ and the reference negative terminals of the energy storage capacitor C _j constitute the jth SLCS type two-port switch sense The input port of the capacitor network unit, the connection end of the energy storage inductor L _j and the four-quadrant power switch S _j ′, and the reference positive terminal of the energy storage capacitor C _j constitute the output of the jth SLCS type two-port switch inductive network unit Port, input single-phase AC power supply reference positive polarity and energy storage capacitor C ₁ reference negative polarity connection end and four-quadrant power switch S ₁ and four-quadrant power switch S ₁ ' connection end is connected with energy storage inductance L ₀ , Where j is a natural number not greater than n; the single-phase high-frequency combination modulation switch is a single-phase full-bridge pulse width modulation rectifier circuit composed of four two-quadrant power switches that bear unidirectional voltage stress and bidirectional current stress.

The circuit structure and principle waveform of a single-stage current-mode AC-DC converter with a series-connected multi-stage switch inductance network are shown in Figures 8 and 9, respectively. In Figures 8 and 9, u _i is the input single-phase AC voltage, Z _L is the output DC load, U _o and I _o are the output DC voltage and DC current respectively, and the symbol of the energy storage capacitor in the multi-level switch inductive network is "+ "Indicates the reference positive terminal of the energy storage capacitor voltage. The multi-level switch inductance network is composed of the energy storage inductor L ₀ and n identical SLCS two-port switch inductance network units cascaded in sequence, where n is a natural number greater than 1, and each SLCS two-port The switch-inductive-capacitance network unit is composed of two four-quadrant power switches S _j and S _j ′, an energy storage inductance L _j , and an energy storage capacitor C _j ; the single-phase high-frequency combination modulation switch is composed of four withstand unit A single-phase full-bridge pulse width modulation rectifier circuit composed of two-quadrant power switches for voltage stress and bidirectional current stress; the output filter can only be a capacitor filter; the input AC power supply u _i and the multi-level switch inductive network can be set Or do not set the input filter, when the input filter is set, the harmonic content of the input AC current can be reduced. When the lower bridge arm of the single-phase high-frequency combined modulation switch (single-phase rectifier bridge) is turned on, the input AC power supply u _i and energy storage capacitors C ₁ ,...C _n have an effect on the energy storage inductance L ₀ , L ₁ ,...L _n Magnetization, the output DC load relies on the capacitor filter to maintain power supply; when the bridge arm switches of the single-phase high-frequency combination modulation switch (single-phase rectifier bridge) are cross-conducted, the energy storage inductors L ₀ , L ₁ , ... L _n are demagnetized and Together with the input AC power u _i , they supply power to the energy storage capacitors C ₁ , ... C _n and the DC load. The multi-stage switch-inductive network and the single-phase high-frequency combined modulation switch (single-phase rectifier bridge) modulate the input AC voltage u _i into a three-phase system whose amplitude changes according to the sinusoidal envelope of twice the input frequency, and the pulse width changes according to the sinusoidal law. State SPWM wave u ₁ , through single-phase high-frequency combined modulation switch (single-phase rectifier bridge) and capacitor filter, high-quality DC voltage u ₂ is obtained on the DC load, that is, the output DC voltage U _o

The single-stage single-phase AC-DC converter of the present invention utilizes n identical SLCS type two-port switch inductive network units cascaded in sequence and the output of the two-port switch inductive network unit in the front stage is the rear stage The single-stage circuit structure of increasing the step-up ratio of the converter by inputting the input of the two-port switch inductive network unit is different from the circuit structure of the traditional single-stage single-phase PWM AC-DC converter (whether a single-phase input power frequency transformer is added or not). Essential difference. Therefore, the single-stage single-phase AC-DC converter of the present invention is novel and creative, and has high conversion efficiency (meaning small energy loss), high power density (meaning small volume and weight), boost ratio Large (meaning that the single-phase input AC voltage with a wider or lower variation range can be converted into the required output DC voltage), input current waveform distortion is small, output voltage waveform ripple is small, high reliability, flexible input voltage configuration, With the advantages of low cost and wide application prospects, it is an ideal energy-saving and consumption-reducing single-phase AC-DC converter, and it has more important value today when vigorously advocating the construction of an energy-saving and conservation-oriented society.

A circuit topology embodiment of a single-stage current-mode AC-DC converter with a series-connected multi-stage switch inductive capacitor network is shown in FIG. 10 . In Figure 10, the output filter is a capacitor filter circuit; the single-phase high-frequency combined modulation switch (single-phase rectifier bridge) can use MOSFET devices, and can also use IGBT, GTR and other devices; the symbol of the energy storage capacitor in the multi-level switch inductive capacitance network "+" indicates the reference positive polarity terminal of the energy storage capacitor voltage. The single-stage single-phase AC-DC converter can convert an unstable low-voltage AC power (such as wind turbines, ground AC power and aviation AC power, etc.) into required stable, high-quality, high-voltage DC, and is widely used in Civil industrial single-phase rectifier power supply for boosting occasions (such as communication rectifier and wind power rectifier 220V50HzAC/380VDC, variable frequency AC voltage/380VDC) and defense industry rectifier power supply (such as aviation rectifier 115V400HzAC/270VDC), etc.

Each energy storage inductor of a single-stage current-mode AC-DC converter with a series multi-stage switch inductive network is magnetized and demagnetized once in a high-frequency switching period T _S , and the corresponding lower bridge arm is turned on during the magnetization period. The period D ₀ T _S , and the demagnetization period corresponds to the bridge arm cross conduction period (1-D ₀ ) T _S (the period of outputting energy to the DC side). The magnetization equivalent circuit of D _{0 TS} during the conduction period of the lower bridge arm of the energy storage inductance of the single-stage single-phase AC-DC converter during the positive and negative half cycles of the input voltage, and the cross-conduction period of the bridge arm (1-D ₀ ) The demagnetization equivalent circuits of T _S are shown in Figures 11, 12, 13, and 14, respectively. In Figures 11, 12, 13, and 14, the polarities of the input voltage u _i and the energy storage capacitor voltage in the multi-level switch inductive network are reference polarities, and the polarities of each current are actual directions.

It is assumed that the terminal voltage of the energy storage capacitor is constant in a high-frequency switching cycle T _S , represented by U _C1 , U _C2 , . . . , U _Cn . From the magnetization equivalent circuit of the energy storage inductor shown in Figures 11 and 13 during the conduction _period of the high-frequency combined modulation switches S ₃ 〞 and _{S 4} 〞, the formula (1.0)-(1.n) can be obtained; The demagnetization equivalent circuit (1-D ₀ ) T _S of the energy storage inductor shown in Figure 12 and 14 during the conduction period of the high-frequency combined modulation switches S ₁ 〞, S ₄ 〞 (S ₂ 〞, S ₃ 〞) can be obtained Formula (2.0)-(2.n); according to the state space averaging method, formula (1)×D ₀ + formula (2)×(1-D ₀ ), let The voltage values of energy storage capacitors U _C1 , U _C2 ,..., U _Cn of the multi-level switch inductive capacitor network are expressed by equations (3.1)-(3.n); The voltage amplitude U ₁ and the voltage U ₂ on the DC side are expressed by formula (4). Therefore, the voltage transfer ratio of a single-stage current-mode AC-DC converter with a series multi-stage switch-capacitance network is

It can be seen from formula (6) that the voltage transfer ratio of the single-stage single-phase AC-DC converter is greater than 1 at different values of n and D ₀ , and is greater than the voltage transfer ratio of the traditional single-stage PWM AC-DC converter D ₀ (Buck type), 1/(1-D ₀ ) (Boost type), D ₀ /(1-D ₀ ) (Buck-Boost type); from the energy storage inductors shown in Figures 11, 12, 13, and 14 It can be seen from the equivalent circuit of magnetization and demagnetization that the single-stage AC-DC converter belongs to the current type (Boost type) converter, especially the step-up ratio of the converter can be increased by increasing the value of n. The multi-stage and single-stage in "single-stage current-mode AC-DC converter with series-connected multi-stage switch inductive network" refer to "the number of stages of the switch inductive network" and "the number of conversion stages of the converter", respectively.

A single-stage current-mode AC-DC converter with a series-connected multi-level switch inductive network has only a single-stage power conversion link, and its control system needs to realize the control of the energy storage capacitor voltage and the output DC voltage of the multi-level switch inductive network. Wind power generation It is also necessary to realize the maximum power point tracking control MPPT of the wind turbine. Therefore, this single-stage single-phase AC-DC converter adopts a dual-loop SPWM control strategy in which the outer loop of the output DC voltage and the inner loop of the energy storage capacitor voltage of the multi-level switch inductive network are controlled, as shown in Figures 15 and 16. The output voltage feedback signal U _of is compared with the reference voltage U _r and the signal after error amplification is used as the reference signal U _Cnr of the inner loop. The energy storage capacitor voltage feedback signal U _Cnf is compared with the reference signal U _Cnr by the absolute value circuit and the error is amplified The signal u _e , u _e intersected with the triangular carrier u _c and the input voltage polarity selection signal are output through a suitable logic circuit and then output single-phase high-frequency combination modulation switch (single-phase rectifier bridge) S ₁ 〞, S ₃ 〞 , S ₂ ″, S ₄ ″ and the control signals of the four-quadrant power switches S ₁ , S ₂ , . . . _, S _n , S ₁ ′, S ₂ ′, . When the input voltage u _i or the output load Z _L changes, the output voltage U _o is stabilized by adjusting the duty ratio signal D ₀ . Therefore, it is feasible for the single-stage single-phase AC-DC converter to use a dual-loop SPWM control strategy in which the output DC voltage outer loop and the multi-level switch inductive network energy storage capacitor voltage inner loop are controlled.

The technical solution 3 of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

A single-stage current-mode AC-AC converter with a series multi-stage switch-inductive network is composed of an input single-phase AC power supply, a single-phase high-frequency combination modulation switch, a single-phase capacitor filter and a single-phase AC load. , and between the input single-phase AC power supply and the single-phase high-frequency combination modulation switch, there is a _multi -stage switch inductance network connected in series; The same SLCS-type two-port switch-inductive network unit is cascaded to form, where n is a natural number greater than 1; each SLCS-type two-port switch-inductive network unit is composed of two four-quadrant power switches S _j and S _j ′ , an energy storage inductor L _j , and an energy storage capacitor C _j . One end of the four-quadrant power switch S _j is connected to one end of the energy storage inductor L _j and the reference positive terminal of the energy storage capacitor C _j . The four-quadrant power switch The other end of S _j and the other end of energy storage inductance L _j are respectively connected to the two ends of four-quadrant power switch S _j ′, and the reference negative polarity end of energy storage capacitor C _j is connected to the adjacent front-stage SLCS type two-port switch The reference positive terminal of the energy storage capacitor at the same position in the inductive network unit is connected, the connection terminal of the four-quadrant power switch S _j and S _j ' and the reference negative terminal of the energy storage capacitor C _j constitute the jth SLCS type The input port of the two-port switch inductance network unit, the connection end of the energy storage inductor L _j and the four-quadrant power switch S _j ′, and the reference positive terminal of the energy storage capacitor C _j constitute the jth SLCS type two-port switch inductance The output port of the network unit, the connection terminal of the input single-phase AC power reference positive polarity and the reference negative polarity of the energy storage capacitor C ₁ and the connection terminal of the four-quadrant power switch S ₁ and S ₁ ′ are connected with an energy storage inductance L ₀ , Where j is a natural number not greater than n; the single-phase high-frequency combined modulation switch is composed of two four-quadrant power switches that bear bidirectional voltage stress and bidirectional current stress, and the four-quadrant power switches S ₁ "and S ₂ " One end is connected to the connection end of the energy storage inductance L _n and the four-quadrant power switch S _n ′, and the other end of the four-quadrant power switch S ₁ "is connected to the reference negative terminal of the input single-phase AC power supply and single-phase output filter capacitor , the other end of the four-quadrant power switch S ₂ ″ is connected to the reference positive terminal of the single-phase output filter capacitor.

The circuit structure and principle waveform of a single-stage current-mode AC-AC converter with a series-connected multi-stage switch inductive network are shown in Figures 17 and 18, respectively. In Figures 17 and 18, u _i is the input single-phase AC voltage, Z _L is the single-phase output AC load (including single-phase AC passive load and single-phase AC grid load), u _o and i _o are the single-phase output AC Voltage and AC current, the symbol "+" of the energy storage capacitor in the multi-level switch inductive network indicates the reference positive polarity terminal of the energy storage capacitor voltage. The multi-level switch inductance network is composed of the energy storage inductor L ₀ and n identical SLCS two-port switch inductance network units cascaded in sequence, where n is a natural number greater than 1, and each SLCS two-port The switch-inductive-capacitance network unit is composed of two four-quadrant power switches S _j and S _j ′, an energy storage inductance L _j , and an energy storage capacitor C _j ; the single-phase high-frequency combined modulation switch is composed of two withstand bidirectional The four-quadrant power switch is composed of voltage stress and bidirectional current stress; the single-phase filter is a single-phase capacitor filter (for single-phase AC passive load) or single-phase CL filter (for single-phase AC grid load); input AC power The input filter can be set or not set between u _i and the multi-level switch inductive network, and the harmonic content of the input AC current can be reduced when the input filter is set. When the single-phase high-frequency combined modulation switch is turned on, the input AC power u _i and energy storage capacitors C ₁ ,...C _n magnetize the energy storage inductors L ₀ , L ₁ ,...L _n , and the output AC load depends on the single-phase capacitor The filter maintains the power supply; when the single-phase high-frequency combination modulation switch is cut off, the energy storage inductors L ₀ , L ₁ , ... L _n are demagnetized and together with the input AC power u _i , supply the energy storage capacitors C ₁ , ... C _n and AC load power supply. The multi-level switch inductive network and the single-phase high-frequency combined modulation switch modulate the input AC voltage u _i into a three-state SPWM wave u ₁ whose amplitude changes according to the law of the sinusoidal envelope of twice the input frequency and whose pulse width is basically the same. After filtering, a high-quality sinusoidal voltage u ₂ is obtained on the AC load, that is, the output voltage u _o .

The single-stage single-phase AC-AC converter of the present invention utilizes n identical SLCS type two-port switch inductive network units cascaded in sequence and the output of the first stage two-port switch inductive network unit is the first The input of the two-stage two-port switch inductive network unit to improve the single-stage circuit structure of the converter boost ratio, and the traditional single-stage single-phase PWM AC-AC converter (whether a single-phase input or output power frequency transformer is added) There is an essential difference in the circuit structure. Therefore, the single-stage single-phase AC-AC converter described in the present invention is novel and creative, and has high conversion efficiency (meaning small energy loss), high power density (meaning small volume and weight), boost ratio Large (meaning that the single-phase input AC voltage with a wider or lower variation range can be converted into the required single-phase output AC voltage), high power factor on the grid side, small output voltage THD, high reliability, flexible input voltage configuration, With the advantages of low cost and wide application prospects, it is an ideal energy-saving and consumption-reducing single-phase AC-AC converter, and it has more important value today when vigorously advocating the construction of an energy-saving and conservation-oriented society.

A circuit topology embodiment of a single-stage current-mode AC-AC converter with a series-connected multi-stage switch inductance network is shown in FIG. 19 . Figure 19 shows the single-phase capacitor filter circuit, which is not shown due to space limitations, and is suitable for single-phase CL filter circuits with higher requirements for output waveform quality; single-phase high-frequency combination modulation switches use MOSFET devices, and can also use IGBT, GTR and other devices; the symbol "+" of the energy storage capacitor in the multi-level switch inductive capacitance network indicates the reference positive polarity terminal of the energy storage capacitor voltage. The AC-AC converter can convert an unstable single-phase low-voltage AC power (such as wind turbines, ground AC power and aviation AC power, etc.) into required stable, high-quality, high-voltage single-phase AC power, and is widely used in Civil industrial single-phase AC regulated and variable voltage power supply (such as electronic transformer 110V50HzAC/220V50HzAC) and national defense industry AC regulated and variable voltage power supply (such as avionics transformer 36V400HzAC/115V400HzAC), etc.

Each energy storage inductor of a single-stage current-mode AC-AC converter with a series multi-stage switch inductive network is magnetized and demagnetized once in a switching cycle T _S , and the magnetization period corresponds to a single-phase high-frequency combined modulation switch D ₀ T _S during S ₁ 〝on (S ₂ 〞off) period, and demagnetization period corresponds to single-phase high-frequency combination modulation switch S ₁ 〝off (S ₂ 〞on) period (1-D ₀ )T _S ( During the energy output to the load side). In the case of the positive and negative half cycles of the input (output) voltage of the AC-AC converter, the energy storage inductance is magnetized during the period of the single-phase high-frequency combined modulation switch S ₁ "on (S ₂ "off) period D ₀ T _S The equivalent circuit and the demagnetization equivalent circuit of (1-D ₀ ) T _S during S ₁ "off (S ₂ "on) are shown in Figures 20, 21, 22, and 23, respectively. In Figures 20, 21, 22, and 23, the polarity of the input voltage u _i is the reference direction, while the polarities of each current are the actual directions.

It is assumed that the terminal voltage of the energy storage capacitor is constant in a high-frequency switching cycle T _S , represented by U _C1 , U _C2 , . . . , U _Cn . From the magnetization equivalent circuit of the energy storage inductor shown in Figures 20 and 22 during the high-frequency combined modulation switch S ₁ "on (S ₂ "off) period, the magnetization equivalent circuit of D ₀ T _S can be obtained as formula (1.0)-(1.n) ; The demagnetization equivalent circuit of the energy storage inductance shown in Figure 21 and 23 during the period (1-D ₀ ) T _S of the high-frequency combined modulation switch S ₁ 〞off (S _{2 〞} on) can be obtained as formula (2.0)- (2.n); According to the state space averaging method, formula (1)×D ₀ + formula (2)×(1-D ₀ ), let The voltage values of energy storage capacitors U _C1 , U _C2 ,..., U _Cn of the multi-level switch inductive capacitor network are expressed by equations (3.1)-(3.n); The voltage amplitude U ₁ and the voltage U ₂ on the DC side are expressed by formula (4). Therefore, the voltage transfer ratio of a single-stage current-mode AC-AC converter with a series multi-stage switch-capacitance network is

It can be seen from formula (7) that the voltage transfer ratio of the single-stage single-phase AC-AC converter is greater than 1 at different values of n and D ₀ , and is greater than the voltage transfer ratio of the traditional single-stage PWM AC-AC converter D ₀ (Buck type), 1/(1-D ₀ ) (Boost type), D ₀ /(1-D ₀ ) (Buck-Boost type); energy storage inductors shown in Figures 20, 21, 22, and 23 It can be seen from the equivalent circuit of magnetization and demagnetization that the single-stage AC-AC converter belongs to the current type (Boost type) converter, especially the step-up ratio of the converter can be increased by increasing the value of n. The multi-stage and single-stage in "single-stage current-mode AC-DC converter with series-connected multi-stage switch inductive network" refer to "the number of stages of the switch inductive network" and "the number of conversion stages of the converter", respectively.

A single-stage current-mode AC-AC converter with a series-connected multi-stage switch inductive network has only a single-stage power conversion link, and its control system needs to realize the control of the output AC voltage, and also needs to realize the maximum power point tracking control of the wind turbine during wind power generation MPPT. Therefore, this single-stage single-phase AC-AC converter adopts the PWM control strategy of output AC voltage instantaneous value feedback, as shown in Fig. 24 and Fig. 25 . The output voltage feedback signal u _of is compared with the reference voltage _ur , the error is amplified, and the absolute value is obtained to obtain the signal _ue , and the signal obtained by intersecting the triangular carrier uc with the triangular _{carrier uc} is used as a single-phase high-frequency combination modulation switch S ₁ "and multiple The control signals of the four-quadrant power switches S ₁ ′, S ₂ ′,…, S _n ′ of the stage switch inductive network, and the inversion signal of the signal obtained by the intersection is used as the single-phase high-frequency combined modulation switch S ₂ ″ and the multi-stage Control signals of the four-quadrant power switches S ₁ , S ₂ , . . . , S _n of the switch inductive network. When the input voltage u _i or the output load Z _L changes, the output voltage u _o is stabilized by adjusting the duty ratio signal D ₀ . Therefore, it is practical and feasible for the single-stage single-phase AC-AC converter to adopt the PWM control strategy of instantaneous value feedback of the output AC voltage.

Claims (3)

1. A single-stage current-mode converter with a multi-stage switch inductive network connected in series is characterized in that: this converter circuit structure is composed of an input DC power supply, a high-frequency combination modulation switch, a capacitor filter and a DC load in sequence Cascade structure, and between the input DC power supply and the high-frequency combined modulation switch in series with a multi-level switch inductance network; the multi-level switch inductance network is composed of energy storage inductance L ₀ and n sequentially cascaded The same SLCS two-port switch inductive network unit is cascaded to form, where n is a natural number greater than 1; each SLCS two-port switch inductive network unit is composed of two power diodes S _j and S _j ', a storage Energy inductor L _j and an energy storage capacitor C _j , the cathode of the power diode S _j is connected to one end of the energy storage inductor L _j and the positive terminal of the energy storage capacitor C _j , the anode of the power diode S _j is connected to the energy storage inductor The other end of L _j is connected to the anode and cathode of power diode S _j ′ respectively, and the negative polarity end of energy storage capacitor C _j is connected to the energy storage capacitor at the same position in the adjacent pre-stage SLCS type two-port switch inductive network unit The positive polarity end of the power diode S _j is connected to the power diode S j _′ and the negative polarity end of the energy storage capacitor C _j constitutes the input port of the jth SLCS type two-port switch inductive network unit, and the energy storage The connection end of the inductor L _j and the power diode S _j ′ and the positive polarity end of the energy storage capacitor C _j form the output port of the jth SLCS type two-port switch inductive network unit, and the positive polarity of the input DC power supply and the energy storage capacitor C _1. An energy storage inductance L ₀ is connected between the connection end of the negative polarity and the connection end of the power diode S ₁ and the power diode S ₁ ′, wherein j is a natural number not greater than n; the high-frequency combination modulation switch is composed of a The two-quadrant power switch S ₁ "and a power diode S ₂ " are composed of a unidirectional voltage stress and a bidirectional current stress. The drain or collector of the two-quadrant power switch S ₁ ", the anode of the power diode S ₂ " and the power diode The cathode of S _n ′ is connected to the connection terminal of the energy storage inductor L _n , the source or emitter of the two-quadrant power switch S ₁ ″ is connected to the negative terminal of the input DC power supply and the negative terminal of the output filter capacitor, and the power The cathode of the diode S ₂ ″ is connected to the positive terminal of the output filter capacitor. 2. A single-stage current-mode converter with a multi-stage switch inductive network connected in series is characterized in that: this converter circuit structure is composed of input single-phase AC power supply, single-phase high-frequency combination modulation switch, capacitor filter and The DC load is cascaded in sequence, and a multi-level switch inductance network is connected in series between the input single-phase AC power supply and the single-phase high-frequency combined modulation switch; the multi-level switch inductance network is formed by the energy storage inductance L ₀ It is composed of n identical SLCS two-port switch inductive network units cascaded in sequence, where n is a natural number greater than 1; each SLCS two-port switch inductive network unit is composed of two four-quadrant power Switches S _j and S _j ′, an energy storage inductance L _j , and an energy storage capacitor C _j constitute one end of the four-quadrant power switch S _j , one end of the energy storage inductance L _j , and the reference positive terminal of the energy storage capacitor C _j The other end of the four-quadrant power switch S _j and the other end of the energy storage inductor L _j are respectively connected to the two ends of the four-quadrant power switch S _j ', and the reference negative end of the energy storage capacitor C _j is connected to the adjacent The reference positive terminal of the energy storage capacitor at the same position in the front-end SLCS type two-port switch inductive network unit is connected, and the connection terminal of the four-quadrant power switch S _j and S _j ' is connected to the reference negative polarity terminal of the energy storage capacitor C _j It constitutes the input port of the jth SLCS type two-port switch inductive network unit, the connection end of the energy storage inductor L _j and the four-quadrant power switch S _j ′ and the reference positive terminal of the energy storage capacitor C _j constitute the jth The output port of the SLCS type two-port switch inductive network unit, the connection terminal of the input single-phase AC power reference positive polarity and the reference negative polarity of the energy storage capacitor C ₁ and the connection between the four-quadrant power switch S ₁ and the four-quadrant power switch S ₁ ′ An energy storage inductance L ₀ is connected between the terminals, where j is a natural number not greater than n; the single-phase high-frequency combined modulation switch is composed of four two-quadrant power switches that withstand unidirectional voltage stress and bidirectional current stress Single-phase full-bridge pulse width modulation rectifier circuit. 3. A single-stage current-mode converter with a series-connected multi-stage switch inductive network, characterized in that: the circuit structure of this converter is composed of input single-phase AC power supply, single-phase high-frequency combination modulation switch, single-phase capacitor filter The device and the single-phase AC load are cascaded in sequence, and a multi-level switch inductance network is connected in series between the input single-phase AC power supply and the single-phase high-frequency combined modulation switch; the multi-level switch inductance network is formed by the storage The energy inductance L ₀ is cascaded with n identical SLCS-type two-port switch-inductive network units cascaded in sequence, where n is a natural number greater than 1; each SLCS-type two-port switch-inductive network unit is composed of two A four-quadrant power switch S _j and S _j ′, an energy storage inductor L _j , and an energy storage capacitor C _j are composed of one end of the four-quadrant power switch S _j and one end of the energy storage inductor L _j and the energy storage capacitor C _j The reference positive terminal is connected, the other end of the four-quadrant power switch S _j and the other end of the energy storage inductor L _j are respectively connected to the two ends of the four-quadrant power switch S _j ', and the reference negative terminal of the energy storage capacitor C _j It is connected with the reference positive terminal of the energy storage capacitor at the same position in the adjacent front-stage SLCS type two-port switch inductive network unit, the connection end of the four-quadrant power switch S _j and S _j ' and the energy storage capacitor C _j The reference negative terminal constitutes the input port of the jth SLCS type two-port switch inductive network unit, the connection terminal of the energy storage inductance L _j and the four-quadrant power switch S _j ' and the reference positive terminal of the energy storage capacitor C _j constitute The output port of the jth SLCS type two-port switch inductive network unit is provided, the connection terminal of the input single-phase AC power supply reference positive polarity and the energy storage capacitor C ₁ reference negative polarity and the connection of the four-quadrant power switch S ₁ and S ₁ ′ An energy storage inductance L ₀ is connected between the terminals, where j is a natural number not greater than n; the single-phase high-frequency combined modulation switch is composed of two four-quadrant power switches that bear bidirectional voltage stress and bidirectional current stress, and the four One end of the quadrant power switch S ₁ ″ and S ₂ ″ is connected to the connection end of the energy storage inductance L _n and the four-quadrant power switch S _n ′, and the other end of the four-quadrant power switch S ₁ ″ is connected to the input single-phase AC power supply, single-phase The reference negative terminal of the phase output filter capacitor is connected, and the other end of the four-quadrant power switch S ₂ "is connected to the reference positive terminal of the single-phase output filter capacitor.