JP2013009509A

JP2013009509A - Charging system

Info

Publication number: JP2013009509A
Application number: JP2011140279A
Authority: JP
Inventors: Yoshitoshi Watanabe; 良利渡辺; Koji Umeno; 孝治梅野
Original assignee: Toyota Central R&D Labs Inc; 株式会社豊田中央研究所
Priority date: 2011-06-24
Filing date: 2011-06-24
Publication date: 2013-01-10
Anticipated expiration: 2031-06-24
Also published as: JP6031222B2

Abstract

PROBLEM TO BE SOLVED: To provide a charging system using a motor for charging a battery from an external single-phase electric power supply so as to suppress a ripple electric current component in DC current to be input in the battery while reducing the costs.SOLUTION: A charging system includes: a battery 16; an inverter 18; a motor 20 connected to the inverter 18; a power factor improvement converter 12; and inverter side control means 32. The power factor improvement converter 12 changes an AC current output from an external AC power supply 24 into a DC power. The DC positive electrode side of the power factor improvement converter 12 is connected to a motor neutral point 36. The inverter side control means 32 includes electric current smooth control means 48 for controlling the inverter 18 so as to suppress a ripple electric current component having frequencies twofold of the electric power supply frequencies for the external AC power supply 24 while charging the battery 16 from the external AC power supply 24.

Description

The present invention relates to a charging system including a battery, a converter connected to the battery, and a motor connected to the converter. For example, the charging system according to the present invention is used as a charging system for an electric vehicle.

2. Description of the Related Art Conventionally, electric vehicles such as an electric vehicle using a motor mounted on the vehicle as a drive source of the vehicle and a hybrid vehicle using at least one of an engine and a motor mounted on the vehicle as a main drive source of the vehicle are known. Such an electric vehicle is equipped with a battery for supplying electric power to the motor. Further, it is considered that a charging system including a motor driving device is configured so that electric power can be exchanged between an AC power source that is an external single-phase power source outside the vehicle and a battery.

For example, Patent Document 1 discloses a first full-wave rectifier circuit connected to a commercial power supply corresponding to an external single-phase power supply, a DC-AC converter connected to the first full-wave rectifier circuit, and a DC-AC converter. An electric vehicle charger is described that includes a connected transformer, a rectifier connected to the transformer, a motor connected to the rectifier, and a battery connected to the motor via an inverter. In this charger, the + side output terminal or the − side output terminal of the battery side rectifier is connected to the neutral point of the three-phase stator coil of the motor. Since the stator coil of the motor fulfills a reactor function for reducing the ripple component in the rectified output of the rectifier when the battery is charged, it is said that the reactor for reducing the ripple component can be omitted.

JP-A-9-233709

In the case of the charger described in Patent Literature 1, ripple current caused by switching of the DC-AC converter can be reduced in the direct current input to the battery using the stator coil of the motor, thereby reducing the ripple current. There is a possibility that the filter for this can be omitted. However, the ripple component pulsating at twice the AC power frequency of the commercial power generated when full-wave rectification is performed is difficult to reduce by using the stator coil because the inductance value of the stator coil is small. On the other hand, the DC-AC converter included in the charger of Patent Document 1 uses a bridge circuit and a smoothing capacitor of a boost type power factor correction circuit, and in the direct current input to the battery, There is a possibility that the ripple current component that pulsates by 2 times can be suppressed. However, the charger disclosed in Patent Document 1 requires a dedicated bridge circuit for suppressing a ripple current component that pulsates at twice the AC power supply frequency, which is improved from the viewpoint of reducing the number of parts and reducing the cost. There is room for.

It is also conceivable to provide a dedicated DC / DC converter on the DC output side of the power factor correction circuit to suppress the ripple current component that pulsates at twice the AC power supply frequency in the DC current input to the battery. In this case as well, a dedicated component for suppressing the ripple current is required, and there is room for improvement in terms of reducing the number of components and reducing the cost.

An object of the present invention is a configuration in which a battery can be charged from an external single-phase power supply using a motor in a charging system, and the direct current input to the battery is twice the AC power supply frequency while reducing costs. It is to suppress the ripple current component that pulsates.

The charging system according to the present invention includes a battery, an inverter connected to the battery, and a motor connected to the inverter, and further converts AC current output from the external single-phase power source into DC current. An AC / DC converter in which the DC positive side of the AC / DC converter is connected to the motor neutral point, and twice the power frequency of the external single-phase power supply when charging the battery from the external single-phase power supply And a current smoothing control means for controlling the inverter so as to suppress a ripple current component having a frequency of.

According to the charging system of the present invention, it is possible to charge a battery from an external single-phase power supply using a motor, and the DC current input to the battery pulsates at twice the AC power supply frequency while reducing the cost. Ripple current component can be suppressed.

It is a figure which shows the circuit structure of the charging system of 1st Embodiment of this invention. FIG. 2 is a diagram illustrating a state in which a battery is charged while controlling a neutral point current of a motor in the charge control method using the configuration of FIG. 1. It is a figure which shows the simulation result of the operation waveform of the battery voltage (battery voltage) Vb at the time of charge in the structure of FIG. 1, and the electric current (battery current) Ib input into a battery. It is a figure which shows the simulation result of the operation waveform of the neutral point current In at the time of charge in the structure of FIG. It is a figure which shows the simulation result of the operation waveform of the external alternating current power supply voltage (power supply voltage) Vs at the time of charge in the structure of FIG. 1, and the external alternating current power supply current (power supply current) Is. It is a figure which shows the circuit structure of the charging system of a comparative example. FIG. 5 is a diagram illustrating simulation results of operation waveforms of a battery voltage (battery voltage) Vb during charging and a current (battery current) Ib input to the battery when it is assumed that there is no bridge circuit in the comparative example of FIG. 4. . FIG. 5 is a diagram illustrating a simulation result of an operation waveform of a neutral point current In during charging when it is assumed that there is no bridge circuit in the comparative example of FIG. 4. 5 is a diagram showing simulation results of operation waveforms of an external AC power supply voltage (power supply voltage) Vs and an external AC power supply current (power supply current) Is during charging when it is assumed that there is no bridge circuit in the comparative example of FIG. . It is a figure which shows the circuit structure of the charging system of 2nd Embodiment of this invention. It is a circuit diagram which shows a mode that various detection signals are input into the charger side control means by the structure of FIG. It is a block diagram which shows a mode that the high power factor converter which is a charger and is an AC / DC converter is controlled by the charger side control means of FIG. FIG. 7 is a circuit diagram showing how various detection signals are input to the inverter-side control means in the configuration of FIG. 6. It is a block diagram which shows a mode that an inverter is controlled by the inverter side control means of FIG. It is a figure which shows the circuit structure of the charging system of 3rd Embodiment of this invention.

[First Embodiment]
1, FIG. 2, FIG. 3A, FIG. 3B, and FIG. 3C show a first embodiment of the present invention. The charging system of the present embodiment is a motor driving device 10, an AC / DC converter, and a power factor correction converter (PFC) 12, which is a charger, an inverter-side control means 32, a charger-side control means 34, And a ripple filter 14.

The motor drive device 10 includes a battery 16 that is an in-vehicle battery, and a positive side of the battery 16 is connected to a positive side via a first relay R1 that is a first switch, and a negative side of the battery 16 is directly, that is, not via a switch. Includes a motor driving inverter 18 connected to the negative electrode side and a motor 20 connected to the inverter 18. Such a motor drive device 10 is, for example, an electric vehicle using the battery 16 as a power source and the motor 20 as a vehicle drive source, or a hybrid vehicle such as a plug-in hybrid vehicle including the engine and the motor 20 as a vehicle drive source. And the motor 20 is driven using the electric power of the battery 16. The charging system is mounted on a vehicle and is an external commercial power source, and can charge the battery 16 from an external AC power source 24 that is an external single-phase power source. Although not shown in FIG. 1, an internal inductance 94 is provided on the external AC power supply 24 side as shown in FIG. 6 for explaining a second embodiment to be described later.

The motor 20 is, for example, a three-phase AC motor. When the motor 20 is driven, the voltage of the battery 16 is output to the inverter 18 by connecting the first relay R1. The inverter 18 includes three-phase arms A1, A2, and A3. Each phase arm A1, A2, and A3 includes two switching elements S1 connected in series and a diode connected in antiparallel to each switching element S1. D1. The midpoint of each phase arm A 1, A 2, A 3 is connected to one end of a corresponding phase stator coil 26 constituting the motor 20. The switching element S1 is a MOSFET, IGBT, transistor, or the like. The inverter side control means 32 controls the switching of each switching element S1 of the inverter 18.

The power factor correction converter 12 is not shown in detail, but a diode rectifier such as a diode rectifier bridge including a diode rectifier or a rectifier that is a diode rectifier, a power factor corrector having a switching element and a reactor, Including a full-wave rectifier circuit. The external AC power source 24 is connected to a power connector 28 that is a first connector, and the AC side of the rectifying unit is connected to a vehicle connector 30 that is a second connector.

Further, in the power factor improvement unit, on / off of switching of the switching element of the power factor improvement unit is controlled by the charger-side control unit 34, and the waveform of the current output from the power factor improvement unit is an alternating current output from the rectification unit. Control is performed so as to approximate a waveform similar to the voltage waveform, that is, to approximate a sine wave in a current discontinuous mode or the like. The full wave rectification circuit unit converts the alternating current output from the power factor correction unit into full wave rectification. Therefore, as shown in FIG. 2, when the AC voltage Vs and the AC current Is of the external AC power supply 24 are defined and the AC current Is is input to the power factor correction converter 12, a full-wave rectified DC current Ia is obtained. Is output. As described above, the power factor correction converter 12 converts the alternating current Is output from the external alternating current power supply 24 into the direct current Ia.

Returning to FIG. 1, the motor neutral point 36, which is the neutral point of the three-phase stator coil 26 of the motor 20, via the second relay R <b> 2 in which the DC positive side of the power factor correction converter 12 is a motor side switch. It is connected to the.

Motor drive device 10 includes a capacitor 38 connected in parallel to inverter 18 between the positive electrode side and the negative electrode side of inverter 18. The positive side of the capacitor 38 is connected to the positive side of the inverter 18, and the negative side of the capacitor 38 is connected to the negative side of the inverter 18 and the battery 16. The first relay R1 is provided between the positive side of the capacitor 38 and the positive side of the battery 16. Further, the inverter unit 40 is configured by the inverter 18 and the capacitor 38.

The charging system also includes a third relay R3 that is a second switch and a switch control means 42. The third relay R3 is provided between the DC positive electrode side of the power factor correction converter 12 and the positive electrode side of the battery 16. Further, the direct current negative electrode side of the power factor correction converter 12 and the negative electrode side of the battery 16 are connected.

The switch control means 42 controls the first relay R1 so that the positive electrode side of the capacitor 38 and the positive electrode side of the battery 16 are disconnected when charging the battery 16 from the external AC power supply 24, and the second relay R2 and the second relay R2 The second relay R2 and the third relay R3 are controlled so that the third relay R3 is turned on, that is, connected. When the third relay R3 is turned on, the DC positive side of the power factor correction converter 12 and the positive side of the battery 16 are connected.

Further, the switch control means 42 sets the first relay R1 so that the positive side of the capacitor 38 and the positive side of the battery 16 are connected when the motor 20 is driven by the power of the battery 16 such as when the vehicle is driven. Control. At the same time, the switch control means 42 controls the second relay R2 and the third relay R3 so that the second relay R2 and the third relay R3 are turned off, that is, disconnected. In this state, the inverter-side control means 32 controls the switching of the switching element S1 of the inverter 18, and controls the torque of the motor 20 in accordance with a detection signal of an accelerator sensor that detects an operation amount of an accelerator pedal (not shown). Do.

The ripple filter 14 is connected between the power factor correction converter 12 and the battery 16. Specifically, the ripple filter 14 includes a reactor 44 connected via a third relay R3 between the DC positive electrode side of the power factor improving converter 12 and the positive electrode side of the battery 16, and the battery 16 side of the reactor 44. And a capacitor 46 connected between the end and the DC negative electrode side of the power factor correction converter 12. The ripple filter 14 suppresses a ripple current caused by switching included in the current output from the power factor correction converter 12 when charging the battery 16 from the external AC power supply 24.

According to such a charging system, it is possible to charge the battery 16 from the external AC power supply 24 using the inverter 18 and the motor 20 constituting the motor driving device 10, the power factor correction converter 12, and the ripple filter 14. it can. Further, when charging the battery 16 from the external AC power supply 24, the first, second, and third relays R1, R2, and R3 are controlled as described above, so that the AC power of the external AC power supply 24 is converted to a power factor correction converter. 12 is converted to DC power and the battery 16 is charged. The first relay R1 and the third relay R3 are used to electrically disconnect the battery 16 and elements that do not need to be connected to the battery 16 when the device is stopped.

Further, the inverter side control means 32 has a current smoothing control means 48. At the time of charging, the current smoothing control means 48 calculates an AC power having a frequency twice the AC power supply frequency, which is an output on the DC side of the power factor correction converter 12, and further calculates an AC current Ic corresponding to the AC power. Calculate. That is, the voltage Vs and current Is of the external AC power supply 24 shown in FIG. 2, the voltage Vb of the battery 16, and the current Ib input to the battery 16 are detected and input to the current smoothing control means 48 (FIG. 1). The The current smoothing control unit 48 calculates AC power having a frequency twice the AC power source frequency from the voltage Vs and current Is of the external AC power source 24, and is obtained by dividing the AC power by the voltage Vb of the battery 16. | Ir | which is the absolute value of the current command on the output side of the power factor correction converter 12, that is, the direct current Ia is calculated. This direct current Ia fluctuates at twice the frequency of the alternating current power supply frequency. Then, by subtracting Ib, which is the average value of the current input to the battery 16, from this DC current Ia, the AC current Ic to be passed through the motor neutral point 36 (FIG. 1) is calculated. Then, the current smoothing control means 48 controls the switching of the inverter 18 so that the zero-phase current of the motor 20 follows Ic. As a result, the motor neutral point current In becomes an alternating current Ic.

On the other hand, a small-capacity ripple filter 14 (FIG. 1) that removes only the switching frequency component is connected to the output side of the power factor correction converter 12. Further, among the direct current Ia pulsating at a frequency twice the alternating current power supply frequency, which is the direct current output current of the power factor improving converter 12, the medium corresponding to the alternating current Ic having a frequency twice the alternating current power supply frequency. Since the sex point current In flows to the inverter 18 side, the smoothed DC current Ib which is the remaining current component flows to the battery 16 side.

According to such a charging system, it is possible to charge the battery 16 from the external AC power supply 24 using a motor, and at a low DC cost, the DC current input to the battery is twice the AC power supply frequency. The ripple current component that pulsates can be suppressed, that is, smoothed. That is, when a pulsating current flows into the battery 16 when charging the battery 16 from the external AC power supply 24, the inflow current exceeds the allowable current of the battery 16, resulting in an overcurrent or a drop in the internal impedance of the battery 16. There is a possibility that the battery 16 voltage fluctuates and becomes overvoltage and cannot be charged. Moreover, the temperature rise of the battery 16 at the time of charge may become large, and deterioration may be accelerated | stimulated. On the other hand, unlike the present embodiment, a DC / DC converter may be provided on the output side of the power factor correction converter 12 to suppress pulsation of the direct current input to the battery 16. However, in this case, there is a room for improvement in terms of cost reduction because the number of dedicated parts for suppressing the ripple current component that pulsates at twice the AC power supply frequency increases.

Further, in the configuration described in Patent Document 1 described above, an AC power supply frequency is determined in a DC current input to the battery by a bridge circuit and a capacitor provided in a DC-AC converter connected to the output side of the full-wave rectifier circuit. It is also conceivable to suppress a ripple current component that pulsates at a frequency twice as high. However, in this case as well, there is room for improvement from the viewpoint of cost reduction because the number of dedicated parts for suppressing the ripple current component that pulsates at twice the frequency of the AC power supply frequency increases.

On the other hand, according to the present embodiment, the AC current component of the charging current is absorbed using the inverter 18 for driving the motor 20 and the current input to the battery 16 is smoothed. Special parts such as a DC / DC converter for smoothing a ripple current component that pulsates at twice the power supply frequency can be reduced, and the cost can be reduced. Further, the capacity of the smoothing capacitor 46 connected to the output side of the power factor correction converter 12 can be reduced. As a result, the charging system can be reduced in size, cost, and efficiency. The inverter-side control means 32, the charger-side control means 34, and the switch control means 42 can be provided together in one control device, but can also be provided divided into a plurality of control devices for each function.

3A is a diagram showing simulation results of operation waveforms of a battery voltage (battery voltage) Vb during charging and a current (battery current) Ib input to the battery in the configuration of FIG. FIG. 3B is a diagram showing a simulation result of the operation waveform of the neutral point current In during charging in the configuration of FIG. 1. 3C is a diagram showing simulation results of operation waveforms of the external AC power supply voltage (power supply voltage) Vs and the external AC power supply current (power supply current) Is during charging in the configuration of FIG. In the following description, the same elements as those shown in FIGS. 1 and 2 are denoted by the same reference numerals. As can be seen from such simulation results, as shown in FIG. 3C, the motor neutral point current In is twice the AC power frequency as shown in FIG. 3B with respect to the voltage Vs and current Is of the external AC power supply 24. AC current Ic having a frequency of ## EQU1 ## so that the current Ib input to the battery 16 can be a substantially constant smoothed DC current. In the simulation result of FIG. 3A, the fluctuation of the current input to the battery 16 with respect to the target current can be suppressed to a range of ± 10%.

FIG. 4 is a diagram illustrating a circuit configuration of a charging system according to a comparative example. The comparative example of FIG. 4 has a configuration that is substantially the same as the configuration described in Patent Document 1 above. In the comparative example of FIG. 4, a power factor improvement circuit 50 is connected to the external AC power supply 24 via a first full-wave rectifier circuit 49, and a bridge circuit 52 is connected to the power factor improvement circuit 50. A second full-wave rectifier circuit 56 is connected to the bridge circuit 52 via a transformer 54. The DC positive side of the second full-wave rectifier circuit 56 is connected to the motor neutral point 36 of the motor 20, and the DC negative side of the second full-wave rectifier circuit 56 is connected to the negative electrode of the battery 16. An inverter 18 is connected between the battery 16 and the motor 20. A capacitor 38 is connected between the positive electrode side and the negative electrode side of the inverter 18. In such a comparative example, when the battery 16 is charged from the external AC power supply 24, the stator coil 26 of the motor 20 functions as a reactor that reduces the ripple component in the rectified output of the second full-wave rectifier circuit 56. However, even in such a configuration, a dedicated bridge circuit 52 for suppressing a ripple current component that pulsates at twice the frequency of the AC power supply frequency is required as described in the configuration of Patent Document 1 above. There is room for improvement in terms of reducing the number of parts and reducing costs. According to the present embodiment described above, such inconvenience can be solved.

FIG. 5A shows simulation results of operation waveforms of the battery voltage (battery voltage) Vb during charging and the current (battery current) Ib input to the battery when it is assumed that there is no bridge circuit in the comparative example of FIG. FIG. FIG. 5B is a diagram illustrating a simulation result of the operation waveform of the neutral point current In during charging when it is assumed in the comparative example that there is no bridge circuit. FIG. 5C is a diagram illustrating simulation results of operation waveforms of the external AC power supply voltage (power supply voltage) Vs and the external AC power supply current (power supply current) Is during charging when it is assumed that there is no bridge circuit in the comparative example. is there. In the following description, the same elements as those shown in FIG.

As is clear from the simulation results, when there is no bridge circuit in the comparative example, the frequency Vs and current Is of the external AC power supply 24 are twice the frequency of the AC power supply frequency as shown in FIG. 5B. A simple output current of the second full-wave rectifier circuit 56 is output to the motor neutral point current In. For this reason, the current Ib input to the battery 16 has a ripple component that fluctuates so as to have twice the frequency of the AC power supply frequency, and the fluctuation of the current Ib input to the battery 16 with respect to the target current is ± Increased to 100%. On the other hand, according to the present embodiment, the current Ib input to the battery 16 can be sufficiently smoothed as is apparent from the comparison between FIG. 5A and FIG. 3A.

[Second Embodiment]
FIG. 6 is a diagram illustrating a circuit configuration of the charging system according to the second embodiment of the present invention. As shown in FIG. 6, in the present embodiment, only the power factor correction converter 12 is changed in the first embodiment shown in FIGS. That is, the power factor correction converter 12 includes a rectification unit 58 connected to the vehicle connector 30 that is the second connector, and a filter 98 including the capacitor 60 and the filter reactor 96. The rectifier 58 is a diode rectifier such as a diode rectifier bridge including a diode rectifier or a diode rectifier. The capacitor 60 is connected between the rectifying unit 58 and the vehicle connector 30. Each filter reactor 96 is connected between one side or the other side of the capacitor 60 and the rectifying unit 58. The filter reactor 96 can be omitted. An internal inductance 94 of the power source 24 is provided between the external AC power source 24 and the power connector 28.

The power factor correction converter 12 is a forward type converter, and includes a switching element S2, a diode D2 connected in reverse parallel to the switching element S2, a capacitor 62, and a power factor improvement unit 66 having a high frequency insulation transformer 64; And a full-wave rectifier circuit unit 68 connected to the output side of the power factor improving unit 66. The positive side of the diode D2 is connected to one end of the primary side coil of the power factor improving unit 66, and the positive side of another diode D3 is connected to the other end of the primary side coil. The negative electrode side of each of the diodes D2 and D3 is connected to the negative electrode side of the rectifying unit 58. The positive side of the rectifier 58 is connected to the midpoint of the primary coil. The capacitor 62 is connected to both ends of the rectifying unit 58. The on / off switching of the switching element S2 is controlled by the charger-side control means 34 so that the waveform of the current output from the power factor improvement unit 66 is similar to the waveform of the AC voltage of the external AC power supply 24. .

The high-frequency insulation transformer 64 has a function of electrically insulating the external AC power supply 24 and the vehicle side. Further, in the power factor correction converter 12, power factor improvement and high frequency DC / DC conversion can be performed by one switching element S <b> 2, and the converted electric power is input to the high frequency insulation transformer 64. The full wave rectification circuit unit 68 converts the alternating current output from the power factor improvement unit 66 into full wave rectification. That is, the DC output rectified on the secondary side of the high-frequency isolation transformer 64 becomes a DC current Ia that pulsates at twice the AC power supply frequency, but is input to the battery 16 on the same principle as in the first embodiment. The current is smoothed, and the charging system can be reduced in size, cost, and efficiency. Further, the short-circuit current due to the current in the direction indicated by the arrow Q in FIG. 6 when the switching element S2 is turned on is suppressed by the filter reactor 96 or the internal inductance 94 of the power source 24.

Next, a method of controlling the power factor correction converter 12 by the charger side control means 34 will be described with reference to FIGS. FIG. 7 is a circuit diagram showing how various detection signals are input to the charger-side control means 34 in the configuration of FIG. FIG. 8 is a block diagram showing a state where the power factor correction converter 12 which is a charger and is an AC / DC converter is controlled by the charger side control means 34 of FIG. 7 also includes a filter reactor 96 (see FIG. 6) and an internal inductance 94 (see FIG. 6), which are not shown (the same applies to FIGS. 9 and 11 described later). ). In the third embodiment described later with reference to FIG. 11, the filter reactor 96 may be omitted.

The charger side control means 34 shown in FIG. 7 receives a voltage value Vs, which is a detection signal of the AC power supply voltage Vs detected by a voltage sensor (not shown), and a charging power command value PR. The The charging power command value PR is generated by an external control unit (not shown) and input to the charger side control means 34 from the external control unit. Further, the voltage value Vb of the voltage of the battery 16, the current Ib input to the battery 16, and the power factor, which are detection signals from various voltage sensors (not shown) and current sensors (not shown), respectively. The output current Ia of the improvement converter 12 is input to the charger side control means 34. Hereinafter, the same elements as those shown in FIGS. 6 and 7 will be described with the same reference numerals.

As shown in FIG. 8, in the charger side control unit 34, the current command generation unit 70 generates the absolute value | Ir | of the current command value from the voltage value Vs and the charge power command value PR. For example, the peak voltage is detected from the voltage Vs, and the effective value of the voltage Vs is calculated based on the detected peak voltage. Further, the phase θ of the voltage Vs is detected from the detected value of the zero cross point of the voltage Vs. A sine wave having the same phase as the voltage Vs is generated based on the phase θ, and an absolute value | Ir | of the current command is generated from the sine wave, the charging power command value PR, and the effective value of the voltage Vs.

Next, a deviation between the absolute value | Ir | of the current command and the detected value of the output current Ia of the power factor correction converter 12 is input to the proportional compensator 72. In the proportional compensator 72, the control voltage is calculated by multiplying the proportional component so that the detected value of the output current Ia follows the absolute value | Ir | of the current command, and as a disturbance to the control voltage, (k1 · Vb + k2 · | Vs |) is added. Here, k1 and k2 are both constants. The output after the disturbance compensation is divided by the voltage Vb of the battery 16 by the modulation factor calculator 74 to calculate the PWM modulation factor Pd. The PWM modulation rate Pd is output to the PWM signal output unit 76, compared with the carrier signal output from the carrier signal output unit 78, and is an ON / OFF signal of the power factor improvement converter 12 according to the calculated value obtained by the comparison. A certain PWM signal Sp is generated. Then, the power factor correction converter 12 is controlled so that the switching element S2 of the power factor correction converter 12 is turned on / off according to the PWM signal Sp. Thus, by controlling the power factor correction converter 12 by the charger side control means 34, the current on the AC side can be brought close to a sine wave without any disturbance.

The current command generation unit 70 can acquire the voltage value Vs and the charge power command value PR at a time of 1 ms or less, for example, as a sampling time. Further, the charger-side control means 34 can acquire the detected value of the output current Ia of the power factor correction converter 12 at a sampling time of about 100 μs. The carrier signal output unit 78 can output a carrier signal of 40 kHz, for example.

Next, a method for controlling the inverter 18 by the inverter-side control means 32 will be described with reference to FIGS. FIG. 9 is a circuit diagram showing how various detection signals are input to the inverter-side control means 32 in the configuration of FIG. FIG. 10 is a block diagram showing how the inverter 18 is controlled by the inverter-side control means 32 of FIG.

The inverter-side control means 32 shown in FIG. 9 includes a voltage value Vs that is a detection signal of the AC power supply voltage Vs detected by a voltage sensor (not shown) and a current sensor (not shown), and a current value Is. Entered. The inverter-side control means 32 is input to the battery 16 with a voltage value Vb of the voltage of the battery 16 as a detection signal from various voltage sensors (not shown) and a current sensor (not shown). Current Ib, a DC voltage of the inverter 18, a voltage Vd across the capacitor 38, and a motor neutral point current In are input. Hereinafter, the same elements as those shown in FIGS. 6 and 9 will be described with the same reference numerals.

As shown in FIG. 10, in the charger-side control means 34, the pulsating current command generation unit 80 sends a pulsating current command from the voltage values Vs and Vb and the current values Is and Ib to the motor neutral point 36. A current value Ic of the alternating current for generating is generated. The calculation method of the current value Ic is the same as that in the first embodiment shown in FIGS. The current value Ic of the pulsating current command is an AC current for canceling an AC current having a frequency twice the AC power supply frequency included in the output current of the power factor correction converter 12 in the opposite phase.

Further, the deviation between the current value Ic and the detected value of the motor neutral point current In is input to the second proportional compensator 82. In the second proportional compensator 82, the control voltage is calculated by multiplying the proportional component so that the detected value of the motor neutral point current In follows the current value Ic, and the control voltage is calculated by the second modulation factor calculating unit 84. Dividing by the voltage Vd across the capacitor 38, the second PWM modulation rate Pd2 is calculated. The second PWM modulation rate Pd2 is output to the second PWM signal output unit 86, is compared with the carrier signal output from the second carrier signal output unit 88, and the on / off signal of the inverter 18 according to the calculated value obtained by the comparison. A second PWM signal Sp2 is generated. Further, in the example of FIG. 10, in the overvoltage inverter stop unit 90, it is determined that an overvoltage occurs when the voltage Vd across the capacitor 38 exceeds a predetermined threshold, and the inverter 18 is stopped to protect the parts. Is done. On the other hand, when it is determined that no overvoltage occurs, the inverter 18 is controlled so that the switching element S1 of the inverter 18 is turned on / off according to the second PWM signal Sp2 obtained above. In addition, the inverter stop part 90 at the time of overvoltage can also be abbreviate | omitted.

In addition, the pulsating current command generation unit 80 can acquire the voltage values Vs and Vb and the current values Is and Ib at a time of 1 ms or less, for example, as a sampling time. The inverter-side control means 32 can acquire the detected value of the motor neutral point current In at a sampling time of about 100 μs. The second carrier signal output unit 88 can output a carrier signal of 15 kHz, for example.

According to the present embodiment, the power factor correction converter 12 is provided with the high-frequency insulation transformer 64 that electrically insulates the external AC power supply 24 from the vehicle side. And the secondary side can be electrically insulated, and an electric shock countermeasure on the vehicle side can be more easily performed. If the purpose is not to obtain such an insulation effect, a simple transformer having no insulation function may be provided instead of the high-frequency insulation transformer 64. Further, unlike the comparative example shown in FIG. 4 described above, it is not necessary to provide the bridge circuit 52 (FIG. 4) in the power factor correction converter 12, so that the number of parts can be reduced. Other configurations and operations are the same as those of the first embodiment shown in FIGS.

[Third Embodiment]
FIG. 11 is a diagram showing a circuit configuration of the charging system according to the third embodiment of the present invention. In the present embodiment, in the second embodiment shown in FIGS. 6 to 10 described above, the ripple filter 14 is omitted, and the DC positive side of the power factor correction converter 12 that is an AC / DC converter is connected to the motor neutral point 36. Connected to. Further, the DC negative electrode side of the power factor correction converter 12 is connected to the negative electrode of the battery 16. Further, a smoothing reactor Lf and a third relay R3 connected in series are connected in parallel with the first relay R1 provided between the positive electrode of the battery 16 and the positive side of the capacitor 38 and the inverter 18. The charging system also includes switch control means 42 that controls on / off of the first, second, and third relays R1, R2, and R3.

When charging the battery 16 from the external AC power supply 24, the switch control means 42 is configured so that the smoothing reactor Lf is connected in series between the positive electrode side of the battery 16 and the positive electrode side of the capacitor 38 and the inverter 18. The third relay R3 is controlled. Further, the inverter-side control means 32 controls the inverter 18 so that the ripple current in the output current of the power factor correction converter 12 is suppressed by the inductance of the motor 20 and the capacitor 38 connected to the inverter 18. That is, the function of the ripple filter 14 (FIG. 1 and the like) provided in each of the above embodiments can be provided to the stator coil 26 of the motor 20 and the capacitor 38 connected to the inverter 18. Further, the smoothing reactor Lf has a function of suppressing a ripple current component having a frequency twice the power supply frequency of the external AC power supply 24 when the battery 16 is charged from the external AC power supply 24.

In such a charging system, when the motor is driven, the second relay R2 and the third relay R3 are turned off, while the first relay R1 is turned on, and the inverter-side control means 32 controls the inverter 18, whereby the motor 20 Torque control. Further, when the battery 16 is charged, the second relay R2 and the third relay R3 are turned on, while the first relay R1 is turned off. A vehicle connector 30 is connected to a power connector 28 connected to the external AC power source 24. Then, AC power is converted into DC power using the power factor correction converter 12 and the battery 16 is charged. In the present embodiment, the motor neutral point 36 and the DC positive electrode side of the power factor correction converter 12 are connected, and the leakage inductance of the motor 20 and the capacitor 38 connected to the inverter 18 are ripples of the charging current to the battery 16. Used as a suppression filter. Further, when a pulsating component having a frequency twice the AC power supply frequency of the charging current to the battery 16 becomes a problem, the smoothing reactor Lf is connected to the inverter 18 and the capacitor 38 by turning on the third relay R3. Thus, the battery 16 can be charged by smoothing the charging current for the battery 16.

In the case of the charging system of this embodiment as well, the AC power source is configured to be able to charge the battery 16 from the external AC power source 24 using the motor 20, and the AC power source can be reduced in cost while reducing the cost. The ripple current component pulsating at twice the frequency can be suppressed, that is, smoothed. That is, only the smoothing reactor Lf and the third relay R3 are dedicated parts for smoothing the ripple current, so that the number of parts can be reduced and the cost can be reduced. Further, a dedicated capacitor for smoothing the ripple current during charging can be omitted. Other configurations and operations are the same as those of the second embodiment shown in FIGS.

In each of the above embodiments, as the power factor correction converter 12, an AC / DC converter having a simple AC / DC conversion function without a power factor improvement unit may be used.

DESCRIPTION OF SYMBOLS 10 Motor drive device, 12 Power factor improvement converter (PFC), 14 Ripple filter, 16 Battery, 18 Inverter, 20 Motor, 24 External AC power supply, 26 Stator coil, 28 Power supply connector, 30 Vehicle connector, 32 Inverter side control means, 34 charger side control means, 36 motor neutral point, 38 capacitor, 40 inverter unit, 42 switch control means, 44 reactor, 46 capacitor, 48 current smoothing control means, 49 first full wave rectifier circuit, 50 power factor improvement circuit , 52 bridge circuit, 54 transformer, 56 second full-wave rectifier circuit, 58 rectifier, 60, 62 capacitor, 64 high-frequency insulation transformer, 66 power factor improver, 68 full-wave rectifier circuit, 70 current command generator, 72 Proportional compensator, 74 Modulation rate calculator, 76 P M signal output unit, 78 carrier signal output unit, 80 pulsating current command generation unit, 82 second proportional compensator, 84 second modulation factor calculation unit, 86 second PWM signal output unit, 88 second carrier signal output unit, 90 overvoltage Inverter stop, 94 internal inductance, 96 filter reactor, 98 filter.

Claims

A battery, an inverter connected to the battery, and a motor connected to the inverter;
Furthermore, an AC / DC converter for converting an alternating current output from an external single-phase power source into a direct current, wherein the direct current positive electrode side of the AC / DC converter and a motor neutral point are connected;
Charging comprising current smoothing control means for controlling an inverter so as to suppress a ripple current component having a frequency twice as high as the power frequency of the external single-phase power supply when charging the battery from the external single-phase power supply system.
The charging system according to claim 1,
A capacitor connected between the positive electrode side and the negative electrode side of the inverter, wherein the negative electrode side of the capacitor is connected to the negative electrode side of the battery;
An inverter side switch provided between the positive side of the capacitor and the positive side of the battery;
A charging system comprising switch control means for controlling an inverter-side switch so that a positive electrode side of a capacitor and a positive electrode side of a battery are disconnected when charging the battery from an external single-phase power supply.
The charging system according to claim 2,
The direct current negative electrode side of the AC / DC converter and the negative electrode side of the battery are connected,
Furthermore, a converter side switch provided between the direct current positive electrode side of the AC / DC converter and the positive electrode side of the battery is provided,
The switch control unit controls the converter side switch so that the DC positive side of the AC / DC converter and the positive side of the battery are connected when charging the battery from the external single-phase power source.
The charging system according to claim 3,
This is a ripple filter connected between the AC / DC converter and the battery. When charging the battery from the external single-phase power supply, the ripple current caused by switching is included in the current output from the AC / DC converter. A charging system comprising a ripple filter for suppression.
In the charging system according to any one of claims 1 to 4,
A charging system is installed in the vehicle,
The AC / DC converter includes an insulating transformer that electrically insulates the external single-phase power source from the vehicle side.
A battery, an inverter connected to the battery, and a motor connected to the inverter;
Furthermore, an AC / DC converter for converting an alternating current output from an external single-phase power source into a direct current, wherein the direct current positive electrode side of the AC / DC converter and a motor neutral point are connected;
A capacitor connected between the positive electrode side and the negative electrode side of the inverter, wherein the negative electrode side of the capacitor is connected to the negative electrode side of the battery;
A smoothing reactor connected in series between the positive electrode side of the battery and the positive electrode side of the capacitor and the inverter when charging the battery from the external single-phase power source,
The ripple current in the output current of the AC / DC converter is suppressed by the motor inductance and capacitor,
The smoothing reactor suppresses a ripple current component having a frequency twice the power frequency of the external single-phase power supply when charging the battery.