JP2010098851A - Electric vehicle - Google Patents

Abstract

Noise generated from a motor generator when charging a secondary battery mounted on an electric vehicle connected to an external power source is reduced.
Y-connected motor generators 50a, 50b, inverters 30a, 30b connected to the motor generators 50a, 50b, a boost converter 20a connected to the inverters 30a, 30b, and a boost converter 20a. The hybrid vehicle 100 includes a battery 11a that can be charged and discharged and a control unit 80, and the battery 11a is charged by an external power source 68 connected to the neutral points 60a and 60b of the motor generators 50a and 50b. The control unit 80 charges the battery 11a after reducing the output side target voltage of the step-up converter 20a to an external charging target voltage lower than each motor generator drive voltage and higher than the voltage of the battery 11a and higher than the voltage of the external power supply 68. Has charging means.
[Selection] Figure 1

Description

  The present invention relates to a structure of an electric vehicle.

  In recent years, electric vehicles such as hybrid vehicles and electric vehicles that drive a vehicle by combining an engine and a motor have been increasingly used. The hybrid vehicle travels by combining two types of power sources, that is, an engine and a motor generator, and includes a rechargeable battery that can be charged and discharged to drive the motor generator. When the required power is low or the vehicle speed is low, the hybrid vehicle stops running the engine and runs with a motor generator using the power of the secondary battery.If the required power is high or the vehicle speed is high When driving on the output of both the engine and the motor generator and traveling on a deceleration or downhill road, the motor generator generates power, and the generated power is regenerated and charged to the secondary battery to improve fuel efficiency. Is something you can do.

  In the hybrid vehicle, when the remaining capacity of the secondary battery decreases due to running by the motor generator, the engine is started and the secondary battery is charged. However, in recent years, there has been a demand for a hybrid vehicle that can make full use of all-electric running that stops at the output of the motor generator with the engine stopped. When the remaining capacity of the secondary battery decreases, a household outlet or charging station is required. A secondary battery is charged by connecting a vehicle to an external power source such as the above.

  When charging a secondary battery from a household outlet, etc., it is necessary to convert the household AC power source to a DC power source and adjust the power supply voltage to a voltage suitable for charging the secondary battery. For this reason, it is not economical to install a separate charger. Therefore, as described in Patent Document 1, an external power source is connected to the neutral point of the motor generator winding, and the AC power source is connected to the inverter by the ON / OFF operation of the switching element in the inductance of the motor generator winding and the inverter. It is proposed to charge the secondary battery by adjusting the voltage to a voltage suitable for charging the secondary battery.

  As described above, when power conversion and voltage adjustment are performed by switching operation of the inverter, noise due to the operation of the switching element is generated from the inverter, and the noise becomes a problem when charging from the external power source. was there. In Patent Document 1, when charging a secondary battery by connecting to an external power source, it is proposed to reduce noise by setting the on / off carrier frequency of the switching element to a non-audible range.

  In addition, since the output of a secondary battery decreases when the temperature is low, when the hybrid vehicle starts at a low temperature, the temperature of the secondary battery is quickly increased to reduce the output of the secondary battery. Control is required. In Patent Document 2, when a hybrid vehicle is started in a low-temperature environment, there is a method of increasing the output target voltage of the boost converter, increasing the ripple current of the switching element of the boost converter, and increasing the temperature of the secondary battery. Proposed.

JP 2008-5659 A JP 2006-6073 A

  On the other hand, when the secondary battery is charged by the conventional technique described in Patent Document 1, electrical energy is stored in the winding using the inductance of the winding of the motor generator, and the stored electrical energy is switched to the inverter. Since the element is discharged by the on / off operation of the element to convert alternating current into direct current, the stator and rotor of the motor generator are vibrated by the current ripple generated by the operation of the switching element, and noise is generated from the motor generator. This noise is often lower than the carrier frequency, and as in the prior art described in Patent Document 1, there are many cases where the noise cannot be eliminated even if the carrier frequency is changed to a non-audible range.

  An object of the present invention is to reduce noise generated from a motor generator when a secondary battery mounted on an electric vehicle is connected to an external power source.

  An electric vehicle according to the present invention includes two vehicle drive motor generators each having a Y-connected stator, each inverter connected to each motor generator and including a plurality of switching elements, and each inverter connected to each of the plurality of switching elements. Including a step-up converter, a rechargeable battery connected to the step-up converter, and a control unit for controlling on / off of each switching element, and connected to each neutral point of the Y connection of each motor generator In the electric vehicle that charges the secondary battery with an external power source, the control unit lowers the output side target voltage of the boost converter below each motor generator drive voltage when noise reduction is necessary, and It is characterized by having a charging means for charging the secondary battery after being reduced to an external charge target voltage that is equal to or higher than the voltage and equal to or higher than the external power supply voltage.

  In the electric vehicle of the present invention, the boost converter includes a first switching element connected to the high voltage side electric circuit of the inverter and a second switching element connected to the reference electric circuit of the inverter, and the charging means includes the boost converter. It is also preferable to charge the secondary battery by turning on and off each switching element of the inverter with the first switching element turned on.

  The electric vehicle of the present invention includes a plurality of power sets that are connected in parallel to each inverter and configured by a boost converter and a secondary battery, and each boost converter is connected to a high-voltage side electric circuit of each inverter. 1 and the second switching element connected to the reference electric circuit of the inverter, the charging means compares the potentials of the secondary batteries, and the potential of each secondary battery has a difference of a predetermined voltage or more. In some cases, the secondary battery with the lower potential is cut off, the first switching element of the boost converter connected to the secondary battery with the higher potential is turned on, and the switching element of the inverter is turned on and off by the on / off operation. When the secondary battery is charged and the potential difference between the secondary batteries is smaller than the predetermined voltage, the first switching element of each boost converter is turned on and each inverter is switched on. Charging the secondary battery by on-off operation of the quenching device is also suitable as a.

  The present invention has an effect of reducing noise generated from a motor generator when charging a secondary battery mounted on an electric vehicle connected to an external power source.

  Preferred embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the hybrid vehicle 100 of the present embodiment includes an engine 61, a first motor generator 50a, a second motor generator 50b, and the output of the engine 61 as a driving force to the first motor generator 50a and the wheels 63. And a power split mechanism 62 that splits the power into two. Each of the motor generators 50a and 50b is a three-phase rotating electric machine having U-phase, V-phase, and W-phase coils 51a, 52a, 53a, 51b, 52b, and 53b in the stator and a permanent magnet in the rotor. Phase, V phase, and W phase coils 51a, 52a, 53a, 51b, 52b, and 53b are Y-connected and have neutral points 60a and 60b, respectively. One end of power cables 64a and 64b from an external power supply 68 is connected to each neutral point 60a and 60b. A plug 66 with an external power source 68 is attached to the other end of the power cables 64a and 64b. Plug 66 is configured to be connected to an external power supply and neutral points 60a and 60b of motor generators 50a and 50b by being inserted into a socket 67 provided on the external power supply 68 side. A capacitor 65 is connected between each of the power cables 64a and 64b. A power source voltmeter 59 for detecting the voltage at both ends of the capacitor 65 is attached to one of the power cables 64b. A total of 58 is attached. Ammeters 56a, 57a, 56b, and 57b for detecting currents in the V and W phases are attached to the V and W phase output cables of the motor generators 50a and 50b, respectively. The hybrid vehicle 100 is equipped with a car navigation system 70 so that information on the position and time of the hybrid vehicle 100 is input to the control unit 80.

  A power supply device 10 is connected to each motor generator 50a, 50b. The power supply device 10 includes a first inverter 30a connected to the first motor generator 50a, a second inverter 30b connected to the second motor generator 50b, and a booster to which the first inverter 30a and the second inverter 30b are connected. It includes a converter 20a, a battery 11a that is a chargeable / dischargeable secondary battery connected to the boost converter 20a, and a control unit 80 that controls the boost converter 20a and each of the inverters 30a and 30b. The battery 11a and the boost converter 20a are common to the inverters 30a and 30b, and the inverters 30a and 30b are connected in parallel to the boost converter.

  The battery 11a is provided with a battery voltage detector 69a for detecting the voltage, a low-voltage side capacitor 13a is provided in parallel with the battery 11a between the battery 11a and the boost converter 20a, and the low-voltage side capacitor 13a has both ends thereof. A low-voltage side voltage detector 54a is provided for detecting the voltage of. Between the boost converter 20a and each of the inverters 30a and 30b, a discharge resistor 15 and a high voltage side capacitor 14 are provided in parallel, and the high voltage side capacitor 14 is provided with a high voltage side voltage detector 55 for detecting the voltage at both ends thereof. ing. Further, a system main relay 12a for cutting off the battery 11a from the power supply system is provided between the low voltage side capacitor 13a and the battery 11a.

  The reference electric circuit 49a of the boost converter 20a is connected in common between the negative side of the battery 11a and the negative side of the first inverter 30a, and the low-voltage path 48a on the input side is connected to the positive side of the battery 11a, and is boosted. The high voltage side high piezoelectric path 47a is connected to the plus side of the first inverter 30a. The reference electrical circuit 49a is connected to the reference electrical circuit 49b of the second inverter 30b, and the high piezoelectric circuit 47a is connected to the high piezoelectric circuit 47b of the second inverter. As described above, the boost converter 20a is a bidirectional converter that is connected to the first and second inverters 30a and 30b in a non-insulating manner.

  As shown in FIG. 1, the boost converter 20a includes an upper arm transistor 21a that is a switching element, a lower arm transistor 22a, and a reactor 25a that stores electromagnetic energy. In the upper arm transistor 21a and the lower arm transistor 22a, the emitter terminal of the upper arm transistor 21a and the collector terminal of the lower arm transistor 22a are connected in series, and the collector terminal of the upper arm transistor 21a is connected to the high piezoelectric path 47a. The emitter terminal of the arm transistor 22a is connected to the reference electric circuit 49a. The base terminals of the upper arm transistor 21 a and the lower arm transistor 22 a are connected to the control unit 80, and the transistors 21 a and 22 a are turned on / off according to commands from the control unit 80.

  An upper arm diode 23a and a lower arm diode 24a are connected in reverse parallel between the emitter terminals and the collector terminals of the transistors 21a and 22a so that the direction from each emitter terminal to the collector terminal is the forward direction. Has been.

  A connection point 71a between the upper arm transistor 21a and the lower arm transistor 22a is connected to the low piezoelectric path 48a, and a reactor 25a that accumulates electromagnetic energy is provided between the connection point 71a of the low piezoelectric path 48a and the positive side of the battery 11a. ing.

  As shown in FIG. 1, each of the inverters 30a and 30b includes a plurality of transistors that perform switching operations of U, V, and W phases and diodes that are connected in antiparallel to the transistors. The emitter terminals of the U-phase upper arm transistors 31a and 31b and the collector terminals of the U-phase lower arm transistors 32a and 32b are connected in series, and the collector terminals of the U-phase upper arm transistors 31a and 31b are connected to the high-voltage paths 47a and 47b. The emitter terminals of the U-phase lower arm transistors 32a and 32b are connected to the reference electric circuits 49a and 49b. A connection point between each U-phase upper arm transistor 31a, 31b and each U-phase lower arm transistor 32a, 32b is connected to each U-phase coil 51a, 51b of each motor generator 50a, 50b. Between each emitter terminal and each collector terminal of each U-phase transistor 31a, 31b, 32a, 32b, each U-phase is connected in reverse parallel so that the direction from each emitter terminal to the collector terminal is the forward direction. The arm diodes 33a and 33b are connected to the U-phase lower arm diodes 34a and 34b. Each base terminal of each U-phase upper arm transistor 31a, 31b and each U-phase lower arm transistor 32a, 32b is connected to the control unit 80, and each U-phase transistor 31a, 31b, 32a, 32b is a command of the control unit 80. ON / OFF operation.

  Similarly, the emitter terminals of the V-phase upper arm transistors 35a and 35b and the collector terminals of the V-phase lower arm transistors 36a and 36b are connected in series, and the collector terminals of the V-phase upper arm transistors 35a and 35b are connected to the high piezoelectric paths. The emitter terminals of the V-phase lower arm transistors 36a and 36b are connected to the respective reference electric circuits 49a and 49b. A connection point between each V-phase upper arm transistor 35a, 35b and each V-phase lower arm transistor 36a, 36b is connected to each V-phase coil 52a, 52b of each motor generator 50a, 50b. Between each emitter terminal and the collector terminal of each V-phase transistor 35a, 35b, 36a, 36b, each V-phase is connected in reverse parallel so that the direction from each emitter terminal to the collector terminal is the forward direction. The arm diodes 37a and 37b are connected to the V-phase lower arm diodes 38a and 38b. Each base terminal of each V-phase upper arm transistor 35a, 35b and each V-phase lower arm transistor 36a, 36b is connected to the control unit 80, and each V-phase transistor 35a, 35b, 36a, 36b is a command of the control unit 80. ON / OFF operation.

  Similarly, the emitter terminals of the W-phase upper arm transistors 39a and 39b and the collector terminals of the W-phase lower arm transistors 40a and 40b are connected in series, and the collector terminals of the W-phase upper arm transistors 39a and 39b are connected to the respective collector terminals. Connected to the high piezoelectric paths 47a and 47b, the emitter terminals of the W-phase lower arm transistors 40a and 40b are connected to the reference electrical paths 49a and 49b. A connection point between each W-phase upper arm transistor 39a, 39b and each W-phase lower arm transistor 40a, 40b is connected to each W-phase coil 53a, 53b of each motor generator 50a, 50b. Between each emitter terminal and collector terminal of each W-phase transistor 39a, 39b, 40a, 40b, each W-phase is connected in reverse parallel so that the direction from each emitter terminal to the collector terminal is the forward direction. The arm diodes 41a and 41b and the W-phase lower arm diodes 42a and 42b are connected. Each base terminal of each W-phase upper arm transistor 39a, 39b and each W-phase lower arm transistor 40a, 40b is connected to the control unit 80, and each W-phase transistor 39a, 39b, 40a, 40b is a command of the control unit 80. ON / OFF operation.

  The control unit 80 is a computer that includes a CPU that performs signal processing and calculations therein, and a memory that stores programs, control data, and the like. The low voltage side voltage detector 54a, the high voltage side voltage detector 55, the respective ammeters 56a, 57a, 56b, 57b, 58, the power source voltmeter 59, and the battery voltage detector 69a are connected to the control unit 80, and the control unit Reference numeral 80 is configured to be able to acquire detection signals from the voltage detectors 54a and 55, the ammeters 56a, 57a, 56b, 57b and 58, and the power source voltmeter 59. The system main relay 12a is also connected to the control unit 80, and is turned on / off according to a command from the control unit 80.

In normal operation, the control unit 80, boosting the voltage of the low voltage side voltage detector and the low-voltage side voltage V _L detected by 54a, high side voltage V _H and the boost converter 20a detected by the high side voltage detector 55 each The operation is controlled so as to be the target high-voltage side voltage V _HC which is the drive voltage of the motor generators 50a and 50b.

  In the hybrid vehicle 100 configured as described above, an operation of charging the battery 11a by the external power source 68 will be described with reference to FIG.

When the hybrid vehicle 100 is stopped in a normal state, the target high-pressure-side voltage V _HC motor-generator 50a is output target voltage of the boost converter 20a, which is set in the control unit 80, 50b for driving the For example, it is set to 400V.

When the plug 66 of the hybrid vehicle 100 is inserted into the socket 67 of the external power source 68, the external power source 68 and each of the motor generators 50a and 50b are connected, and the battery 11a can be charged from the external power source 68, FIG. As shown in step S <b> 101, the control unit 80 acquires the position and time information of the hybrid vehicle 100 from the car navigation system 70. If it is determined that the hybrid vehicle 100 is located in a residential area and is going to be charged by a commercial commercial power source, or if it is determined that it is going to be charged at night, the steps of FIG. as shown in S102, to reduce the target high-pressure-side voltage V _HC of the boost converter 20a to lower external charging target voltage than the driving voltage of the normal motor-generator.

In this operation, the control unit 80 obtains the external power supply voltage V _A from the power supply voltage meter 59 detects the battery voltage V _B by the battery voltage detector 69a, the external charging target voltage lower than the motor-generator driving voltage The battery voltage is V _B or higher and the external power supply voltage V _A or higher. For example, when the external power source is a commercial commercial power source and the external power source voltage _VA is 100 V and the battery voltage V _B is 200 V, the external charging target voltage is set to 200 V or a voltage between 200 V and 400 V. To do. This is because when the external charging target voltage is lower than the battery voltage V _B can not charge the battery 11a, when external charging target voltage is lower than the external power supply voltage V _A, each inverter 30a, 30b the switching operation of the This is because the voltage cannot be boosted by.

Control unit 80, upon reducing the target high-pressure-side voltage _{V HC} of the boost converter 20a to the external charging target voltage, as shown in step S103 of FIG. 2, and turns on the upper arm transistor 21a of the boost converter 20a. As a result, the high piezoelectric path 47a of the boost converter 20a is connected to the positive side of the battery 11a. Since the reference electric circuit 49a of the boost converter 20a is connected to the negative side of the battery 11a, the battery 11a and the first and second inverters 30a and 30b are directly connected by turning on the upper arm transistor 21a of the boost converter 20a. Connected.

As shown in step S104 in FIG. 2, the control unit 80 reacts the reactance of each coil 51a, 52a, 53a, 51b, 52b, 53b of each motor generator 50a, 50b and the upper and lower arms of each phase of each inverter 30a, 30b. By the on / off operation of the transistor, the voltage of the external power supply 68 is boosted to the target high voltage V _HC reduced in step S102 of FIG. At this time, the control unit 80 calculates the required boost voltage from the external power supply voltage V _A acquired by the power supply voltmeter 59 and the target high-voltage side voltage V _Hc, and the upper and lower arms of each phase so as to obtain this boost required voltage. Controls the on-duty of the transistor. Then, to get the high side voltage V _H by a high-side voltage detector 55, the feedback control is performed so that the high-pressure-side voltage V _H is the target high side voltage V _HC.

  The electric power boosted by the inverters 30a and 30b is smoothed by the high-voltage side capacitor 14, and charged to the battery 11a via the upper arm transistor 21a in which the boost converter 20a is turned on.

  As shown in step S105 of FIG. 2, the control unit 80 monitors the remaining capacity of the battery 11a, and when the remaining capacity reaches a predetermined target value, for example, full charge or 70% of the remaining capacity, FIG. As shown in step S106, the switching operation of each of the inverters 30a and 30b is stopped, the upper arm transistor 21a of the boost converter 20a is turned off, and the charging of the battery 11a by the external power source 68 is terminated.

If it is determined in step S101 of FIG. 2 that the charging is not nighttime charging but residential charging, as shown in step S107 of FIG. 2, the target high-voltage side voltage V _HC of the boost converter 20a is determined. Is maintained as a normal motor generator drive voltage, the upper and lower arm transistors of each inverter 30a, 30b are turned on and off to boost the external power supply 68 to charge the battery 11a. Then, as shown in step S108 in FIG. 2, charging is stopped when the remaining capacity of the battery 11a reaches a predetermined target value.

At the time of charging, a ripple current is generated by the on / off operation of each switching transistor of each inverter 30a, 30b, and this ripple current generates noise from the stator and rotor of each motor generator 50a, 50b. The magnitude of this ripple current increases as the boosted voltage of each inverter 30a, 30b increases, and the noise generated by this ripple current increases as the boosted voltage of each inverter 30a, 30b increases. In the present embodiment, by reducing the target high-pressure-side voltage V _HC of the boost converter 20a to lower external charging target voltage than the driving voltage of the normal motor-generator, so it is charging the battery 11a, the inverters 30a, The boosted voltage by 30b is reduced, and as a result, the ripple current and the noise level can be reduced as shown in FIGS.

Figure 3 shows the change in position and a maximum ripple current of the rotor of the first motor-generator 50a, line a in the figure, without reducing the target high side voltage V _HC of the boost converter 20a, the usual the maximum ripple current when the charge remains set, the line b indicates the maximum ripple current when the charging by performing a reduction of the target high-pressure-side voltage V _HC of the boost converter 20a. As shown in FIG. 3, it can be seen that the present embodiment has the effect of greatly reducing the maximum ripple current regardless of the position of the rotor of the first motor generator 50a. Further, FIG. 4 shows the relationship between the position and the noise level of the rotor of the first motor-generator 50a, the line c in the figure, without reducing the target high side voltage V _HC of the boost converter 20a, It shows the noise level at the time of charging remains normal setting, the line d indicates the noise level at the time of charging by performing the reduction of the target high-pressure-side voltage V _HC of the boost converter 20a. As shown in FIG. 4, in this embodiment, it can be seen that the noise level is greatly reduced regardless of the position of the rotor of the first motor generator 50a.

In the present embodiment, the external charging target voltage can be freely set as long as it is lower than the motor generator driving voltage and within the voltage range of the battery 11a or higher and the external power supply voltage or higher. Further, since the noise generated from each motor generator 50a, 50b decreases as the boosted voltage at each inverter 30a, 30b decreases, for example, the position of the hybrid vehicle acquired from the car navigation system 70 faces a large road even in a residential area. However, if you are in a place where noise is not a concern, or if it is early in the night, increase the external charging target voltage, and if it is late at night or in a quiet residential area, lower the external charging target voltage. You may make it. For example, when the motor generator driving voltage is 400 V, the external power supply voltage _VA is 100 V, which is a commercial voltage for home use, and the battery voltage V _B is 200 V, the external charging target voltage is used in a quiet residential area at midnight. In a place where early hours and nighttime noises do not bother much at night, for example, it may be about 250V to 300V.

In this embodiment, the voltage of the battery 11a is acquired by the battery voltage detector 69a. However, the low voltage side voltage _VL is detected by the low voltage side voltage detector 54a provided in the low voltage side capacitor 13a. The voltage of the battery 11a may be used.

  Next, another embodiment of the present invention will be described with reference to FIGS. Parts similar to those of the embodiment described with reference to FIGS. 1 to 4 are denoted by the same reference numerals and description thereof is omitted. As shown in FIG. 5, this embodiment includes two sets of batteries and boost converters, and each battery and boost converter set is connected in parallel with each inverter. As shown in FIG. 5, the reference electric circuit 49a of the boost converter 20a is connected in common between the negative side of the battery 11a and the negative side of the first inverter 30a, and the low-voltage path 48a on the input side is connected to the positive side of the battery 11a. The high-voltage side high-voltage path 47a after being connected and boosted is connected to the plus side of the first inverter 30a. Similarly, the reference electric circuit 49b of the boost converter 20b is connected in common between the negative side of the battery 11b and the negative side of the second inverter 30b, and the low piezoelectric path 48b on the input side is connected to the positive side of the battery 11b. The high-voltage side high piezoelectric path 47b after boosting is connected to the plus side of the second inverter 30b. The reference electrical path 49a is connected to the reference electrical path 49b, and the high piezoelectric path 47a is connected to the high piezoelectric path 47b. Each step-up converter 20a, 20b is a bidirectional converter connected non-insulated to the first and second inverters 30a, 30b.

  Boost converter 20b has the same configuration as boost converter 20a, and low voltage side voltage detector 54b, upper arm transistor 21b, lower arm transistor 22b, battery voltage detector 69b, and system main relay 12b are connected to control unit 80.

An operation when charging the two batteries 11a and 11b of the hybrid vehicle 100 configured as described above from the external power source 68 will be described. As shown in step S <b> 201 of FIG. 6, the control unit 80 acquires position and time information from the car navigation system 70 to the hybrid vehicle 100. If it is determined that the hybrid vehicle 100 is located in a residential area and is going to be charged by a commercial commercial power source, or if it is determined that it is going to be charged at night, the steps in FIG. as shown in S202, to reduce the boost converter 20a, the target high-pressure-side voltage V _HC and 20b to the normal low external target charging voltage than the driving voltage of the motor generator. The setting of the external charging target voltage is the same as in the embodiment described above.

Control unit 80, once reduced boost converter 20a, the target high-pressure-side voltage _{V HC} and 20b to the external charging target voltage, as shown in step S203 in FIG. 2, compare two batteries 11a, and 11b potential difference. The control unit 80 acquires the voltage of each battery 11a, 11b from each battery voltage detector 69a, 69b, acquires the voltage difference, and when the potential of each battery 11a, 11b has a difference of a predetermined value or more. Determines that there is a difference between the potentials of the two batteries 11a and 11b. If the potential difference between the two batteries 11a and 11b is greater than or equal to a predetermined value, as shown in step S211 of FIG. 6, the upper arm transistor of the boost converter connected to the higher potential battery is turned on, As shown in step S212 in FIG. 6, the system main relay of the other battery is turned off to shut off the battery from the power supply system.

  Then, as shown in step S213 in FIG. 6, as in the previous embodiment, the upper and lower arm transistors of the inverters 30a and 30b are turned on / off to boost the external power supply, and the battery with the higher potential is charged.

  The control unit 80 acquires the potentials of the batteries 11a and 11b during charging and monitors the potential difference. When the potential difference between the batteries 11a and 11b becomes smaller than the predetermined potential difference, as shown in step S204 in FIG. 6, the voltage on the boost converters 20a and 20b connected to the batteries 11a and 11b is increased. Both arm transistors 21a and 21b are turned on, and as shown in step S205 of FIG. 6, the upper and lower arm transistors of the inverters 30a and 30b are on / off controlled to boost the external power source and charge the batteries 11a and 11b. . Then, as shown in steps S206 and 207 of FIG. 6, charging is stopped when the remaining capacity of each of the batteries 11a and 11b reaches a predetermined target value.

  This embodiment has the same effect as the embodiment described above, and charges both batteries after matching the potentials of the batteries 11a and 11b, so that the batteries 11a and 11b are charged evenly. The battery can be prevented from being deteriorated due to the potential difference between the batteries 11a and 11b.

1 is a system diagram showing a configuration of a hybrid vehicle in an embodiment of the present invention. It is a flowchart of the charging operation by the external power supply of the hybrid vehicle in the embodiment of the present invention. It is a graph which shows the relationship between the rotor position of a motor generator, and the maximum ripple current. It is a graph which shows the relationship between the rotor position of a motor generator, and a noise level. It is a systematic diagram which shows the structure of the hybrid vehicle in other embodiment of this invention. It is a flowchart of the charging operation by the external power supply of the hybrid vehicle in other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Power supply device, 11a, 11b Battery, 12a, 12b System main relay, 13a, 13b Low voltage side capacitor, 14 High voltage side capacitor, 15 Discharge resistor, 20a, 20b Boost converter, 21a, 21b Upper arm transistor, 22a, 22b Lower arm Transistor, 30a, 30b Inverter, 47a, 47b High piezoelectric circuit, 48a, 48b Low piezoelectric circuit, 49a, 49b Reference circuit, 50a, 50b Motor generator, 51a-53a, 51b-53b Coil, 54a, 54b Low voltage side voltage detector, 55 High voltage side voltage detector, 59 Power supply voltmeter, 60a, 60b Neutral point, 61 Engine, 62 Power split mechanism, 63 Wheel, 66 Plug, 67 Socket, 68 External power supply, 69a, 69b Battery voltage detector, 70 Car navigation Cis Beam, 80 control unit, 100 a hybrid vehicle, _{V A} external power supply voltage, _{V B} battery voltage, _{V H} high side _{voltage, V HC} target high-side voltage, _{V L} low-side voltage.

Claims (3)

Two vehicle drive motor generators having a Y-connected stator, each inverter connected to each motor generator and including a plurality of switching elements, a boost converter connected to each inverter and including a plurality of switching elements, and a booster A secondary battery connected to the converter and chargeable / dischargeable, and a controller for controlling on / off of each switching element, and connected to each neutral point of the Y connection of each motor generator by an external power source An electric vehicle for charging,
When noise reduction is necessary, the control unit reduces the output side target voltage of the boost converter to an external charging target voltage that is lower than each motor generator drive voltage and above the secondary battery voltage and above the external power supply voltage. An electric vehicle comprising charging means for charging a secondary battery. The electric vehicle according to claim 1,
The step-up converter includes a first switching element connected to the high-voltage side circuit of the inverter, and a second switching element connected to the reference circuit of the inverter,
The charging means turns on the first switching element of the boost converter and charges the secondary battery by the on / off operation of each switching element of the inverter.
An electric vehicle characterized by. The electric vehicle according to claim 1,
It is connected in parallel with each inverter, and has a plurality of power supply sets composed of a boost converter and a secondary battery,
Each boost converter includes a first switching element connected to the high-voltage side circuit of each inverter, and a second switching element connected to the reference circuit of the inverter,
The charging means compares the potentials of the secondary batteries, and if there is a difference of a predetermined voltage or more between the potentials of the secondary batteries, the secondary battery with the lower potential is cut off and the secondary battery with the higher potential is disconnected. When the first switching element of the boost converter connected to the secondary battery is turned on and the secondary battery is charged by the on / off operation of each switching element of the inverter, and the potential difference between the secondary batteries is smaller than a predetermined voltage, Charging the secondary battery by turning on and off each switching element of the inverter by turning on the first switching element of each boost converter;
An electric vehicle characterized by.

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