JP4893113B2 - Control device for rectifier circuit - Google Patents

Description

The present invention relates to a control device of the rectifier circuit which converts the ac voltage into a DC voltage.

A system that converts an N-phase AC voltage into a DC voltage by an AC / DC converter made of a semiconductor switching element and supplies the DC voltage to a load is well known.
For example, FIG. 11 shows a configuration of a rectifier disclosed in Patent Document 1. In FIG. 11, 1 is a three-phase AC power source, 10 is a rectifier, and 2 is a load such as an inverter connected to the output side of the rectifier 10.

The rectifier 10 includes a semiconductor switching element, such as an IGBT, and a diode that are anti-parallel, and a bridge circuit that connects the main circuit 11, an AC reactor 12, a smoothing capacitor 13, and a phase voltage of the three-phase AC power source 1. The phase voltage detector 14 for detecting the voltage, the voltage detector 15 for insulatingly converting the R phase voltage of the three-phase AC power supply 1, and the angle signal θ (θ = 0 ° to 360 °) synchronized with the phase of the R phase voltage. Angle signal generating means 16, generating a sine wave generator 17 for generating a sine wave based on the angle signal θ, and generating a sine wave based on an angle signal θ ₁ obtained by adding 120 ° to the angle signal θ. A sine wave generator 18, a voltage regulator 21 that performs an adjustment operation based on a deviation between a voltage set value obtained by the voltage setter 19 and a voltage detected value obtained by detecting the DC voltage across the capacitor 13 via the voltage detector 20; Voltage adjustment A multiplier 22 for multiplying vessel 21 output and the output of the sine wave generator 17 and 18 respectively, R-phase current command value _i ^{R *} and T-phase current command output from these multipliers 22, 23 The S phase current command value i _S ^* is obtained from the value i _T ^* , and each phase current command value i _R ^* , i _S ^* , i _T ^* and each phase current detection value i _R , i _S detected by the current detector 24 are obtained. , I _T , respectively, and current regulators 25, 26, 27 that adjust and calculate deviations, and phase voltage command values V _R ^* , V _S ^* , V _T output from these current regulators 25, 26, 27. A comparator 29 that outputs a PWM signal by comparing ^* with the carrier signal from the carrier signal generator 28, and a gate drive that generates a gate signal for the switching element of the main circuit 11 based on the PWM signal from the comparator 29 Circuit 30 It is.
In the rectifier 10, when a power supply abnormality such as an instantaneous power failure or a phase loss occurs in the three-phase AC power supply 1, the abnormality is detected by the power supply abnormality detection circuit 200 and the operation of the rectifier 10 is stopped. It has become.

Next, FIG. 12 shows a rectifier circuit and its control device disclosed in Patent Document 2.
In the rectifier circuit of FIG. 12, 1a is a three-phase AC power source, 2a _{load, 3 RS, 3 ST, 6} C1, 6 C2 the voltage _{detector, 4 R, 4 S, 4} T a current _{detector, 5} R, 5 _S and 5 _T are bidirectional switch circuits capable of controlling current bidirectionally, R, S and T are AC input terminals, P and N are positive and negative DC output terminals, and L _R , L _S and L _T are Reactors C ₁ and C ₂ are capacitors.

Each of the bidirectional switch circuits 5 _R , 5 _S , 5 _T is configured by connecting a series circuit of two switching elements and a series circuit of two diodes in parallel, and S _R1 , S _R2 , S _{S1, S S2, S T1,} S T2 are switching elements such as IGBT or _{MOSFET, D R1 ~D R4, D} S1 ~D S4, D T1 ~D T4 are diodes.
Diode _{D R1, D R2} together connection point is connected to one end of the reactor _{L R,} the switching element _{S R1, S R2} together connection point is connected to the capacitor _C 1, _{C 2} connection point between the NP. Further, both ends of the series circuit of the switching elements S _R1 and S _R2 are connected to both ends of the series circuit of the capacitors C ₁ and C ₂ via the diodes D _R3 and D _R4 .

Similarly, the connection point between the diodes D _S1 and D _S2 is connected to one end of the reactor L _S , and the connection point between the switching elements S _S1 and S _S2 is connected to the connection point NP between the capacitors C ₁ and C _2. In addition, both ends of the series circuit of the switching elements S _S1 and S _S2 are connected to both ends of the series circuit of the capacitors C ₁ and C ₂ via the diodes D _S3 and D _S4 .
Furthermore, the diode _{D T1, D T2} between the connection point is connected to one end of the reactor _{L T,} the switching element _{S T1, S T2} with a connection point between being connected to the connection point NP, the switching element _{S T1,} Both ends of the series circuit of S _T2 are connected to both ends of the series circuit of capacitors C ₁ and C ₂ via diodes D _T3 and D _T4 .

Next, the operation of the control device 100 will be described together with the configuration.
The input line voltages V _RS , V _ST detected by the voltage detectors 3 _RS , 3 _ST are converted into phase voltages V _R , V _S , V _T by the phase voltage converter 31, and these input phase voltages V _R , V _T are converted. Polarity discriminating signals R ⁺ , R ⁻ , S ⁺ , S ⁻ , T ⁺ , T ⁻ are generated by the polarity discriminator 32 in synchronization with the polarities of _{S 1} and V _T. In addition, the voltage V _C1 of the capacitor C ₁ detected by the voltage detector 6 _C1 is fed back to the DC voltage command value 33, and the input phase voltage V _R by the multipliers 35 _Ra , 35 _Sa , and 35 _Ta via the voltage regulator 34b. , V _S and V _T respectively. Similarly, the voltage V _C2 of the capacitor C ₂ detected by the voltage detector 6 _C2 is fed back to the DC voltage command value 33, and the input phase voltage is output by the multipliers 35 _R , 35 _S and 35 _T via the voltage regulator 34 a. Multiply V _R , V _S , and V _T , respectively.

To phase the input current command value is these multiplication results, the current detector _{4 R,} 4 S, ₄ phase input current detected by _{T I R,} I S, and feeding back the _{I T,} the current regulator _{36 Ra} , 36 _Sa , 36 _Ta and the comparators 37 _Ra , 37 _Sa , 37 _Ta are compared with the carrier signal 40 to obtain PWM signals for the switching elements S _R2 , S _S2 , S _T2 , and the current regulators 36 _R , 36 _Ta , The PWM signals for the switching elements S _R1 , S _S1 , S _T1 are obtained by comparison with the carrier signal 40 by the comparators 37 _R , 37 _S , 37 _T via 36 _S , 36 _T.
Further, the polarity determination signal ^{R +, R -, S +} , S -, T +, T - and the logically ANDed with a PWM signal by the AND gate ₃₈ R _{to 38 DEG Ta,} the gate driver circuit ₃₉ R _{~ 39 Ta} The drive signals of the switching elements S _R1 , S _R2 , S _S1 , S _S2 , S _T1 , S _T2 are created via

In the above configuration, for example, when the R-phase voltage _V R> S-phase voltage _{V S,} the ON pulse width of the switching element _{S S2} when the voltage _{V C1} of the capacitor _{C 1} drops becomes wider, the switching element S when the voltage _{V C1} rises _The control device 100 operates so that the on-pulse width of _S2 is narrowed. Maintained _{Thus, R → L R → D R1} → D R3 → C 1 → S S2 → D S2 → L S → S → charging current changes capacitor _{C 1} that flows in the path of the R, the voltage _{V C1} constant Is done.
Meanwhile, pulse width of the switching element _{S R1} becomes wider when the voltage _{V C2} of the capacitor _{C 2} is lowered, the control device 100 so that the on pulse width is reduced the switching device _{S R1} when the voltage _{V C2} rises to work. Maintained Thus, the _{R → L R → D R1 →} S R1 → C 2 → D S4 → D S2 → L S → S → charging current of the capacitor _{C 2} flows in the path of the R is changed, voltage _{V C2} is constant Is done.

Therefore, according to the control device of Patent Document 2, the voltages V _C1 and V _C2 of the capacitors C ₁ and C ₂ can be independently controlled. Further, the input current is controlled to a sinusoidal waveform synchronized with the input voltage by feedback control of the input current, and the output voltage (capacitor voltage) can also be controlled to a constant DC voltage by feedback control. For this reason, it is possible to convert the AC voltage into a constant DC voltage while controlling the input current at a high power factor.
Also in this control apparatus, when a power supply abnormality such as an instantaneous power failure or a phase failure occurs in the AC power supply 1a, the power supply abnormality detection circuit 200 detects this abnormality and the control apparatus 100 stops the operation of the rectifier circuit. It has become.

JP-A-9-163752 ([0012] to [0016], FIG. 1 etc.) JP 2002-142458 A ([0027] to [0030], FIG. 4, FIG. 5 etc.)

In the prior art shown in FIG. 11 or FIG. 12, the operation of the rectifier 10 and the control device 100 must be stopped when the power supply is abnormal such as a phase failure of the AC power supply. However, depending on the load conditions, there is a case where the operation must be continued, and there is also a request that the apparatus is continuously operated using the voltage of the healthy phase particularly when the power supply is in a phase failure.
In addition, depending on where the device is used, a three-phase AC power supply may not be prepared. In this case, it is desirable that a three-phase device can be operated with a single-phase AC power source. On the other hand, when operating a three-phase specification device with a single-phase AC power source, the input current for each phase is √3 times that of a three-phase AC power source, so the input current exceeds the rated current for three-phase operation. There is a risk that it may flow, and there is concern about the failure of the main circuit.

  Therefore, the problem to be solved by the present invention is that both a multi-phase AC power source such as a three-phase power source and a single-phase AC power source can be used, and an overcurrent flows even when a power source abnormality such as an open phase occurs during multi-phase operation An object of the present invention is to provide a control device for a rectifier circuit that can be continuously operated by switching to single-phase operation.

In order to solve the above problem, the invention described in claim 1 is a rectifier circuit capable of converting an AC voltage of N (N is a natural number of 3 or more) phase into a DC voltage by N bidirectional switch circuits, Connect the AC input side of each bidirectional switch circuit to N AC input terminals, and connect the positive DC output terminal and negative DC output terminal of each bidirectional switch circuit together to connect these positive and negative DC output terminals. Two capacitors are connected in series, and a connection point between the two capacitors is connected to each bidirectional switch circuit, and the terminals of the two capacitors are turned on and off by the switching elements in these bidirectional switch circuits. In the rectifier circuit that can individually control the voltage between
An (N-1) phase AC power source connected between (N-1) AC input terminals;
Means for detecting an input voltage between lines connected to the AC power supply;
Means for detecting a voltage between terminals of each capacitor;
Means for generating an (N-1) -phase input current command value that causes the terminal voltage of each capacitor to follow the DC voltage command value of each capacitor using the input voltage;
(N-1) means for detecting an alternating current input current of the phase;
Means for generating a drive signal for the switching element in the bidirectional switch circuit connected to the (N-1) phase so that the (N-1) phase AC input current follows the input current command value, respectively. ,
It is equipped with.

The invention described in claim 2 is a rectifier circuit capable of converting an AC voltage of N (N is a natural number of 2 or more) phase into a DC voltage by N bidirectional switch circuits, and an AC of each bidirectional switch circuit. Connect the input side to N AC input terminals respectively, connect the positive DC output terminal and negative DC output terminal of each bidirectional switch circuit together, and connect two capacitors in series between these positive and negative DC output terminals In addition, the connection point between the two capacitors can be connected to each bidirectional switch circuit, and the voltage between the terminals of the two capacitors can be individually controlled by the on / off operation of the switching element in these bidirectional switch circuits. In the rectifier circuit
Means for detecting an input voltage between the N-phase lines;
Means for detecting a power supply abnormality from the detected input voltage;
Means for detecting a voltage between terminals of each capacitor;
Means for generating an input current command value that causes each terminal voltage of each capacitor to follow the DC voltage command value of each capacitor, using the input voltage excluding the phase in which a power supply abnormality is detected;
Means for detecting the AC input current of each phase;
Means for generating a drive signal for a switching element in the bidirectional switch circuit connected to a phase other than the phase in which a power supply abnormality is detected so that the AC input current of each phase follows the input current command value, respectively. , With.

The invention described in claim 3 is the control device for the rectifier circuit according to claim 2,
A switch unit such as a thyristor provided on the AC input side of the bidirectional switch circuit and connected in series to any of the switching elements in the bidirectional switch circuit;
And a means for turning off the switch portion of the phase in which the power supply abnormality is detected.

The invention described in claim 4 is the control device for the rectifier circuit according to claim 2 or 3, wherein
A first control operation executed by the control device according to claim 2 or 3 when a power supply abnormality is detected;
A second control operation for individually controlling the switching elements existing in the charging path of each capacitor so that the voltage across the terminals of each capacitor follows the DC voltage command value of each capacitor when the AC input is healthy; Can be switched.

The invention described in claim 5 is the control device for the rectifier circuit described in claim 4,
Means for detecting a zero cross of the input voltage;
When a power supply abnormality is detected, the second control operation is switched to the first control operation at the zero cross timing.

The invention described in claim 6 is the rectifier circuit control device according to claim 4 or 5, wherein
Means for calculating input power or load power,
At the time of detecting a power supply abnormality, when the calculated power exceeds a predetermined value, the operation is stopped without switching from the second control operation to the first control operation.

According to a seventh aspect of the present invention, in the control device for a rectifier circuit according to the first or second aspect,
The bidirectional switch circuit is
A series circuit of two diodes having the same flow direction and a series circuit of two switching elements having the same flow direction are connected in parallel, and the connection points of the two diodes are connected to each other via a reactor. Connect to one phase of the power supply, connect the cathode side of the series circuit of the two diodes to the positive DC output terminal via the diode, respectively, and connect the anode side of the series circuit of the two diodes to the negative electrode via the diode, respectively. And a connection point between the two switching elements is connected to a connection point between the two capacitors.

The invention described in claim 8 is the rectifier circuit control device according to any one of claims 1 to 7,
DC voltage command values are individually set for the two capacitors.

According to the present invention, for example, even when a three-phase AC power supply cannot be prepared or when a power supply abnormality such as a phase failure occurs in the three-phase AC power supply, the switching element in the bidirectional switch circuit of the phase where the AC input exists is turned on / off. By controlling, the rectifier circuit can be operated without any trouble using a single-phase AC power supply, and the voltage between the terminals of two capacitors connected in series on the output side of the rectifier circuit can be individually controlled. it can.
In particular, according to the invention of claim 5, it is possible to prevent fluctuations in the input current and output voltage when switching to the operation when the power supply is abnormal. According to the invention of claim 6, the calculated input power or load power By estimating the input current at the time of operation switching based on the above, it is possible to prevent an overcurrent from flowing in advance.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a rectifier circuit and a control device according to a first embodiment of the present invention, and corresponds to the invention according to claims 1 and 7. This embodiment is effective, for example, when a rectifier circuit is operated using a single-phase AC power source when a three-phase AC power source cannot be prepared.
The configuration of the rectifier circuit in FIG. 1 is the same as that in FIG. 12 except that a single-phase AC power source 1b is connected between the AC input terminals S and T.

The configuration and operation of the control device 100a in FIG. 1 will be described focusing on the differences from the control device 100 shown in FIG.
The control device 100a in FIG. 1 is different from the control device 100 in FIG. 12 in that the voltages of the capacitors C ₁ and C ₂ can be individually controlled even when the input of the rectifier circuit is a single-phase alternating current. . In the control device 100a of FIG. 1, the same components as those of the control device 100 of FIG. 12 are denoted by the same reference numerals.

Enter the input line voltage _{V ST} detected by the voltage detector _{3 ST} to the polarity discriminator 32a, the polarity determination signal synchronized with the polarity of the voltage _{V ST} between the input line ^ST +, ST ^- generates a. Further, the voltage V _C1 of the capacitor C ₁ detected by the voltage detector 6 _C1 is fed back to the DC voltage command value 33, and a charging current command value for the capacitor C ₁ is generated via the voltage regulator 34b. Similarly, the voltage V _C2 of the capacitor C ₂ detected by the voltage detector 6 _C2 is fed back to the DC voltage command value 33, and a charging current command value for the capacitor C ₂ is generated via the voltage regulator 34a.

Next, the absolute value | V _ST | of the input line voltage V _ST is detected by the absolute value circuit 42, and this charging value command value is multiplied by the absolute value | V _ST | by the multipliers 35 _T and 35 _Ta. To generate an input current command value for each phase. For these input current command value, the input current _I S detected by the current detector ₄ S, _{4 T,} the _{I T} feedback respectively, via a current regulator _{36 S, 36 Sa, 36 T} , 36 Ta comparison A PWM signal is generated by comparing with the carrier signal 40 by means of the units 37 _S , 37 _Sa , 37 _T , 37 _Ta .

Further, the logical product of the polarity determination signals ST ⁺ and ST ⁻ and the PWM signal is obtained by AND gates 38 _{S to} 38 _Ta , and the single-phase AC power source 1 b is connected through the gate drive circuits 39 _{S to} 39 _Ta. A gate signal is generated for each switching element S _S1 , S _S2 , S _T1 , S _T2 of the bidirectional switch circuit 5 _S , 5 _T of the current phase.
On the other hand, the gate command circuit 41 turns off both the switching elements S _R1 and S _R2 of the R-phase bidirectional switch circuit 5 _R to which the single-phase AC power source 1 b is not connected.

The operation principle of this embodiment will be further described.
For example, when the input line voltage V _ST > 0 (the polarity determination signal ST ⁺ is “High” level), the output of the voltage regulator 34 b increases when the voltage V _C1 of the capacitor C ₁ decreases, and the multiplier 35 _Ta etc. , The output of the current regulator 36 _Ta also increases. Thus, the comparator _{37 Ta,} the AND gate _{38 Ta,} the controller 100a via the gate drive circuit _{39 Ta} as the ON pulse width of the switching element _{S T2} becomes wider to operate. Further, when the voltage _{V C1} of the capacitor _{C 1} increases the output of the voltage regulator 34b is reduced, reducing the output of the current regulator _{36 Ta} via the multiplier _{35 Ta} or the like. Thus, the comparator _{37 Ta,} the AND gate _{38 Ta,} the controller 100a via the gate drive circuit _{39 Ta} as the ON pulse width of the switching element _{S T2} is narrowed to operate.
_{Thus, S → L S → D S1} → D S3 → C 1 → S T2 → D T2 → L T → T → charging current of the capacitor _{C 1} flows in a path S is changed, the voltage _{V C1} of the capacitor _{C 1} is Maintained constant.

On the other hand, when the input line voltage V _ST > 0 (the polarity determination signal ST ⁺ is “High” level), the output of the voltage regulator 34a increases when the voltage V _C2 of the capacitor C ₂ decreases, and the multiplier 35 _T etc. increasing the output of the current regulator 36 _T through. Accordingly, the control device 100a operates so that the pulse width of the switching element S _S1 is widened through the comparator 37 _T , the AND gate 38 _T , and the gate drive circuit 39 _T. The output of the voltage _{V C2} of the capacitor _{C 2} rises the voltage regulator 34a is reduced, reducing the output of the current regulator 36 _T via the multiplier 35 _T or the like. Accordingly, the control device 100a operates so that the pulse width of the switching element S _S1 is narrowed via the comparator 37 _T , the AND gate 38 _T , and the gate drive circuit 39 _{T.
Thus, S → L S → D S1} → S S1 → C 2 → D T4 → D T2 → L T → T → charging current of the capacitor _{C 2} flows in the path of the S is changed, the voltage _{V C2} of the capacitor _{C 2} is Maintained constant.

By the operation as described above, even when the single-phase AC power supply 1b is connected, the voltages V _C1 and V _C2 of the capacitors C ₁ and C ₂ can be controlled independently. Further, the input current is controlled to a sine wave waveform synchronized with the input voltage by the feedback control of the input current, and the output voltage (the voltages V _C1 and V _{C2 of the} capacitors C ₁ and C ₂ ) is also changed to a constant DC voltage by the feedback control. Can be controlled. As a result, the AC voltage can be converted to a DC voltage while controlling the input current at a high power factor.
In the first embodiment, the example in which the single-phase AC power source 1b is connected between the S and T phase lines has been described. However, when the single phase AC power source 1b is connected between the R and S phase lines. As the control device, the R, S phase line voltage V _RS and the R phase, S phase input currents I _R , I _S are detected, and the R, S phase switching elements S _R1 , A drive signal for S _R2 , S _S1 , S _S2 may be generated. The same principle may be applied when the single-phase AC power supply 1b is connected between the T and R phase lines.

Next, FIG. 2 is a block diagram of a control device according to the second embodiment of the present invention, which is a modification of the control device of FIG.
In the case of a single-phase AC input, it can be considered that the phase difference of each phase current is 180 °, that is, each phase current is inverted and equal in magnitude (here, I _S = −I _T ). For this reason, a comparator 37 to which a one-phase current, for example, the absolute value | I _S | of the S-phase current I _S is detected by the absolute value circuit 43 in the control device 100b and the output of the current regulator 36 _S is added. _A comparator 37 to which the gate signals of the switching elements S _S1 and S _T1 are obtained from the output of _S via the AND gates 38 _S and 38 _T and the gate drive circuits 39 _S and 39 _T, and the output of the current regulator 36 _Sa is added. The gate signals of the switching elements S _S2 and S _T2 may be obtained from the output of _Sa via the AND gates 38 _Sa and 38 _Ta and the gate drive circuits 39 _Sa and 39 _Ta .
Thereby, even if the number of current detectors, current regulators and comparators is reduced, the same control as in the first embodiment is possible. Since the operation principle is the same as that of the first embodiment, description thereof is omitted.

FIG. 3 is a configuration diagram of a control device according to the third embodiment of the present invention.
This embodiment pays attention to the fact that the voltages V _C1 and V _C2 of the capacitors C ₁ and C ₂ can be individually controlled in the present invention, and the DC voltage command values 33 and 33a are provided in the control device 100c, respectively. The voltages V _C1 and V _C2 are individually controlled.
Note that the voltage control and current control methods are the same as those in the second embodiment, and a description thereof will be omitted. Further, the configuration after the multipliers 35 _S and 35 _Sa in the control device 100c is the same as that shown in FIG. 2, but can also be configured as shown in FIG.

Next, FIG. 4 is a configuration diagram of a rectifier circuit and a control device according to a fourth embodiment of the present invention, and corresponds to the invention according to claim 2.
In this embodiment, a phase loss detector 60 and a selector 50 are provided in the control device 100d, and a phase to be switched is selected based on phase loss information of the AC power supply.
4 shows an example in which the single-phase AC power source 1b is connected between the AC input terminals S and T as in FIG. 1, but this is because the three-phase AC power source is connected to the input terminals R, S, and T. This also includes the case where the R phase is lost when is connected.

The phase loss detector 60 detects the phase loss (in the illustrated example, R R) based on the input line voltages V _RS and V _ST (and the input line voltage V _TR calculated based on these) detected by the voltage detectors 3 _RS and 3 _ST. Phase) is detected and this phase loss information is sent to the selector 50 and the gate command circuit 41. Input line voltage _V RS is the selector _{50, V ST} and the phase currents _I R (and the input line voltage _{V TR} is calculated based on _these), I S, and _{I T} is input, in the open phase Voltage information (input line voltage V _ST ) other than a certain R phase is output to the polarity discriminator 32a and the absolute value circuit 42, and current information other than the R phase (S phase current I _S , T phase current I _T ) is also output. Is fed back to the input side of the current regulators 36 _{S to} 36 _Ta .
Here, FIG. 5 is a diagram for explaining the operation of the selector 50, and shows the input line voltage and the input current selected in accordance with the phase loss information. As previously described, since the single-phase AC power source 1b in FIG. 4 are connected S, between the lines of T-phase, V _{ST, I S,} the I _T is selected in correspondence to the R Aiketsu phase information, output Will do.

That is, in the present embodiment, the rectifier circuit is controlled using the input line voltage and phase current other than the R phase related to the open phase, and the R phase switching elements S _R1 and S _R2 recognized as open phases are gates. Each is turned off by the command circuit 41. Other voltage control and current control methods are the same as in the first embodiment.
According to this embodiment, the rectifier circuit can be controlled using the voltage information and current information of the healthy phase regardless of which phase is lost. Of course, the present invention is applicable not only when the phase is lost but also when the three-phase AC power source 1b is actively used to operate the three-phase rectifier circuit when the three-phase AC power source cannot be procured.

Next, FIG. 6 is a configuration diagram of a rectifier circuit and a control device according to a fifth embodiment of the present invention, and corresponds to the invention according to claim 4.
In this embodiment, the rectifier circuit has the same configuration as that in FIG. 12, and a three-phase AC power source 1a is connected.

With respect to the control device 101, by switching the switch 70 using the phase loss information by the phase loss detector 60a, the control device 100 during the three-phase operation shown in FIG. 12 and the control during the phase loss operation shown in FIG. Switch to device 100d. That is, when the three-phase AC power supply 1a is normal, the three-phase operation of the rectifier circuit according to the prior art of FIG. 12 described above is performed, and when one of the three phases is lost, the first of FIGS. The operation is switched to open phase operation (single phase operation) according to the fourth embodiment.
In addition, since the operation | movement of the three-phase driving | operation and the open phase driving | operation was already demonstrated, detailed description is abbreviate | omitted here.
The phase loss detector 60a is not necessarily provided separately, and the phase loss detector 60 included in the control device 100d of FIG. 4 may be used.

FIG. 7 is a configuration diagram of a control device according to the sixth embodiment of the present invention, and corresponds to the invention according to claim 5.
The control device 101a of this embodiment is different from the control device 101 of FIG. 6 from a zero cross detector 61 that detects zero crosses of the input line voltages V _RS and V _ST, a zero cross detection signal, and an open phase detector 60a. And a latch circuit 62 to which an open phase detection signal is input. With these configurations, when the phase loss is detected, the timing at which control is switched by the switch 70 is set to the zero crossing point of the input line voltage other than the phase that has lost phase (for example, V _ST when phase loss occurs in the R phase). is there.

In the fifth embodiment described above, for example, open phase to R-phase occurs at the peak point of the input line voltage V _ST, so that switch the control to the control unit 100d from controller 100 immediately drives the switch 70 . In this case, in the control device 100d of FIG. 4, each phase current command value is obtained by multiplying the absolute value | V _ST | of the input line voltage V _ST by the charging current command value output from the voltage regulators 34a and 34b. Due to the configuration to generate, a large step occurs in the input signal of the current regulator, and as a result, there is a possibility that a large fluctuation occurs in the input current and the output voltage.
Therefore, focusing on the fact that each phase current command value is generated by multiplying the input line voltage and the charging current command value, if the control is switched at the time of zero crossing of the input line voltage, the input signal of the current regulator Can be prevented from greatly fluctuating.

FIG. 8 is a waveform diagram showing the operation when the R phase is lost. From the top, the input line voltage V _ST , the R phase missing phase detection signal, the zero cross detection signal, and the output of the latch circuit 62 (control switching) Timing).
In the present embodiment, after outputting the phase loss detection signal by detecting the phase loss of R-phase by phase loss detector 60a in FIG. 7, as shown in FIG. 8, synchronized with the zero-cross detection signal of the voltage V _ST between the input line Then, by outputting a control switching signal from the latch circuit 62, a shock at the time of switching from the three-phase operation to the open phase operation (single-phase operation) is suppressed.
Since the operations of the three-phase operation and the open phase operation are as described above, the detailed description thereof is omitted.

Next, FIG. 9 is a configuration diagram of a control device according to the seventh embodiment of the present invention, and corresponds to the invention according to claim 6.
When the control device 101b of this embodiment is compared with the control device 101a of FIG. 7, the input line voltages V _ST and V _RS and the input currents I _R , I _S , and _IT are input to calculate the input power. A power calculation circuit 63 and a comparator 64 that compares the calculated single-phase input power with a single-phase power rating value are added. Here, the output of the comparator 64 is applied to the latch circuit 62.

In this embodiment, when the input power calculated by the input power calculation circuit 63 exceeds the single-phase power rating value, the latch circuit 62 uses the output signal of the comparator 64 even when a phase loss occurs. The control switching signal to the switch 70 is made inactive, and the operation of the apparatus is stopped without switching from the control during the three-phase operation to the control during the phase loss operation.
If switching from three-phase operation to single-phase operation, the input current for each phase will be √3 times that of three-phase operation, and input current that exceeds the rated current for three-phase operation may flow (for example, three-phase operation). If the input current of each phase is 100%, the input current of each phase is 173% during single-phase operation). For this reason, the input power is calculated in advance, and if this exceeds (1 / √3) times the single-phase power rating value, it is assumed that the input current of the rectifier circuit becomes an overcurrent, and the operation of the apparatus is stopped. .
In this embodiment, the determination is made based on the input power, but the determination may be made by detecting the load current and voltage to calculate the load power.

Finally, FIG. 10 is a configuration diagram of a rectifier circuit and a control device according to an eighth embodiment of the present invention, and corresponds to the invention according to claim 3.
In the rectifier circuit of this embodiment, one of the upper and lower arms on the AC input side of the bidirectional switch circuits 5 _R ′, 5 _S ′, 5 _T ′ is connected to, for example, the diodes D _R1 , D _S1 , D _T1 in FIG. Are changed to thyristors T _R1 , T _S1 , T _T1 , and the controller 102 inputs the phase loss detection signal from the phase loss detector 60a to the thyristor control circuit 65 to input the thyristors T _R1 , T _S1 , T T1. The gate signal of _T1 is obtained.

In the present embodiment, when the three-phase AC power supply 1a is normal, all the thyristors T _R1 , T _S1 , and T _T1 are turned on, so that the rectifier circuit and the control device are substantially the same as those in the fifth embodiment of FIG. When a phase failure occurs, the gate of the phase-shifted thyristor is turned off. For example, in the fifth embodiment of FIG. 6, if the single-phase operation is continued when the phase failure state of the three-phase AC power source 1 a is recovered and returns to the normal state, the output voltage, input voltage, and input current are changed. Large fluctuations occur. For this reason, when the phase is lost, the phase-shifted thyristor in FIG. 10 is turned off so that the single-phase operation is not affected even when the AC power supply is restored. In addition, since the operation | movement of a three-phase driving | operation and an open phase driving | operation is as having mentioned above, detailed description is abbreviate | omitted.

In FIG. 10, the upper arm of the bidirectional switch circuits 5 _R ′, 5 _S ′, 5 _T ′ on the AC input side is changed to a thyristor, but the lower arm may be changed to a thyristor. . Also, other semiconductor switching elements such as transistors may be used instead of thyristors.
Furthermore, in the eighth embodiment, the sixth embodiment in FIG. 7 and the seventh embodiment in FIG. 9 can be applied.

It is a block diagram of the rectifier circuit and control apparatus which concern on 1st Embodiment of this invention. It is a block diagram of the control apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram of the control apparatus which concerns on 3rd Embodiment of this invention. It is a block diagram of the rectifier circuit and control apparatus which concern on 4th Embodiment of this invention. It is operation | movement explanatory drawing of the selector in FIG. It is a block diagram of the rectifier circuit and control apparatus which concern on 5th Embodiment of this invention. It is a block diagram of the control apparatus which concerns on 6th Embodiment of this invention. It is operation | movement explanatory drawing of FIG. It is a block diagram of the control apparatus which concerns on 7th Embodiment of this invention. It is a block diagram of the rectifier circuit and control apparatus which concern on 8th Embodiment of this invention. It is a block diagram of the prior art described in patent document 1. FIG. It is a block diagram of the prior art described in patent document 2. FIG.

Explanation of symbols

1a: the three-phase AC power source 1b: single-phase AC power source 2a: Load _{3 RS, 3 ST, 6 C1} , 6 C2: Voltage detector _{4 R, 4 S, 4 T} : current detector _{5 R,} 5 S, 5 _{T , 5 R ', 5 S'} , 5 T ': bidirectional switch circuit 32a: polar classifier 33: DC voltage command value 34a, 34b: voltage regulator _{35 T} ~, 35 _Ta: multiplier 36 _R ~ 36 _Ta: current regulator 37 _R to 37 _TaT: comparator 38 _R to 38 DEG _Ta: aND gate 39 _R ~ 39 _Ta: gate drive circuit 40: a carrier signal 41: the gate command circuit 43: the absolute value circuit 50: selector 60, 60a: Phase loss detector 61: Zero cross detector 62: Latch circuit 63: Input power calculation circuit 64: Comparator 70: Switch 100a to 100d, 101a, 101b, 102: Control device R S, T: AC input terminals P, N: DC output terminals _{L R, L S, L T} : reactor _{C 1,} C _2: Capacitor _{D R1 ~D R4, D S1 ~D} S4, D T1 ~D T4: Diode S _R1 , S _R2 , S _S1 , S _S2 , S _T1 , S _T2 : Semiconductor switching elements T _R1 , T _S1 , T _T1 : Thyristors

Claims (8)

N (N is a natural number of 3 or more) phase AC voltage can be converted into DC voltage by N bidirectional switch circuits, and the AC input side of each bidirectional switch circuit is connected to N AC input terminals. Are connected to each other, and the positive DC output terminal and the negative DC output terminal of each bidirectional switch circuit are connected together, and two capacitors are connected in series between the positive and negative DC output terminals. In the rectifier circuit in which the connection point between each is connected to each bidirectional switch circuit, and the voltage between the terminals of the two capacitors can be individually controlled by the on / off operation of the switching element in these bidirectional switch circuits.
An (N-1) phase AC power source connected between (N-1) AC input terminals;
Means for detecting an input voltage between lines connected to the AC power supply;
Means for detecting a voltage between terminals of each capacitor;
Means for generating an (N-1) -phase input current command value that causes the terminal voltage of each capacitor to follow the DC voltage command value of each capacitor using the input voltage;
(N-1) means for detecting an alternating current input current of the phase;
Means for generating a drive signal for the switching element in the bidirectional switch circuit connected to the (N-1) phase so that the (N-1) phase AC input current follows the input current command value, respectively. ,
A control device for a rectifier circuit, comprising:
N (N is a natural number of 2 or more) phase AC voltage can be converted to DC voltage by N bidirectional switch circuits, and the AC input side of each bidirectional switch circuit is connected to N AC input terminals. Are connected to each other, and the positive DC output terminal and the negative DC output terminal of each bidirectional switch circuit are connected together, and two capacitors are connected in series between the positive and negative DC output terminals. In the rectifier circuit in which the connection point between each is connected to each bidirectional switch circuit, and the voltage between the terminals of the two capacitors can be individually controlled by the on / off operation of the switching element in these bidirectional switch circuits.
Means for detecting an input voltage between the N-phase lines;
Means for detecting a power supply abnormality from the detected input voltage;
Means for detecting a voltage between terminals of each capacitor;
Means for generating an input current command value that causes each terminal voltage of each capacitor to follow the DC voltage command value of each capacitor, using the input voltage excluding the phase in which a power supply abnormality is detected;
Means for detecting the AC input current of each phase;
Means for generating a drive signal for a switching element in the bidirectional switch circuit connected to a phase other than the phase in which a power supply abnormality is detected so that the AC input current of each phase follows the input current command value, respectively. ,
A control device for a rectifier circuit, comprising: In the control device of the rectifier circuit according to claim 2,
A switch unit provided on the AC input side of the bidirectional switch circuit and connected in series to any of the switching elements in the bidirectional switch circuit;
Means for turning off the switch part of the phase in which the power supply abnormality is detected;
A control device for a rectifier circuit, comprising: In the control device of the rectifier circuit according to claim 2 or 3,
A first control operation executed by the control device according to claim 2 or 3 when a power supply abnormality is detected;
A second control operation for individually controlling the switching elements existing in the charging path of each capacitor so that the voltage across the terminals of each capacitor follows the DC voltage command value of each capacitor when the AC input is healthy; The control device of the rectifier circuit characterized by being configured to be switchable. In the control device of the rectifier circuit according to claim 4,
Means for detecting a zero cross of the input voltage;
A control device for a rectifier circuit, wherein when a power supply abnormality is detected, the second control operation is switched to the first control operation at the timing of the zero crossing. In the control device of the rectifier circuit according to claim 4 or 5,
Means for calculating input power or load power,
A control device for a rectifier circuit, wherein, when power supply abnormality is detected, when the calculated power exceeds a predetermined value, the operation is stopped without switching from the second control operation to the first control operation. In the control device of the rectifier circuit according to claim 1 or 2,
The bidirectional switch circuit is
A series circuit of two diodes having the same flow direction and a series circuit of two switching elements having the same flow direction are connected in parallel, and the connection points of the two diodes are connected to each other via a reactor. Connect to one phase of the power supply, connect the cathode side of the series circuit of the two diodes to the positive DC output terminal via the diode, respectively, and connect the anode side of the series circuit of the two diodes to the negative electrode via the diode, respectively. And a connecting point between the two switching elements is connected to a connecting point between the two capacitors. In the control device of the rectifier circuit according to any one of claims 1 to 7,
A control device for a rectifier circuit, wherein a DC voltage command value is individually set for each of the two capacitors.

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