JP2008193788A - Power controller and vehicle equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power controller capable of transmitting and receiving electric power between an electricity-storing device mounted on a vehicle and an electric load or power source outside the vehicle and miniaturizing a filter while having sufficient noise-suppressing effect, and to provide a vehicle equipped with the controller. <P>SOLUTION: Power lines ACL1, ACL2 are connected to neutral points N1, N2 of motor generator MG1, MG2. An ECU 30 controls inverters 10, 20 in such a way that electric power is transmitted and received between the electricity-storing device B and a load 90 connected to a plug 70. A common mode choke coil 40 is arranged on a pair of the power lines. A Y-capacitor 50 is connected between the power lines ACL3, ACL4 and a vehicle ground 80 in between the common mode choke coil 40 and the plug 70. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power control device and a vehicle including the same, and more particularly to a power control device capable of transferring power between a power storage device mounted on the vehicle and an electric load or power source outside the vehicle, and a vehicle including the power control device. About.

  Japanese Patent Laid-Open No. 4-295202 (Patent Document 1) discloses an electric motor drive and power processing apparatus capable of transferring power between an AC power supply outside a vehicle and an in-vehicle DC power supply. This device includes a DC power source, two inverters that are pulse width modulated (hereinafter also referred to as “PWM”), two induction motors, a control unit, an input / output port, an EMI filter, Is provided. Each induction motor includes a Y-connected winding, and an input / output port is connected to the neutral point of each winding.

  In this device, in the recharging mode, the DC power can be charged by converting the AC power applied to the neutral point of each winding from the single-phase power connected to the input / output port into DC power. Further, it is possible to generate sine wave-adjusted AC power between the neutral points of each winding and output the generated AC power to an external device connected to the input / output port.

The EMI filter is provided between the neutral point of each winding and the input / output port, and reduces high-frequency common mode noise appearing at the input / output port (see Patent Document 1).
JP-A-4-295202 JP 2006-101632 A JP 2005-237133 A JP 2002-51566 A

  In general, various devices mounted on a vehicle are strongly required to save space because each device is laid out in a limited space. The device disclosed in Japanese Patent Laid-Open No. 4-295202 is useful in that power can be exchanged between the power storage device and an electric load or power source outside the vehicle using an existing inverter.

  However, in the above apparatus, a filter for reducing the high-frequency common mode voltage generated by the inverter is essential, and the filter is also required to be reduced in size from the viewpoint of space saving. However, Japanese Patent Laid-Open No. 4-295202 does not disclose any specific configuration of the EMI filter from such a viewpoint.

  Therefore, an object of the present invention is to allow electric power to be exchanged between a power storage device mounted on a vehicle and an electric load or power source outside the vehicle, and to reduce the size of the filter while having a sufficient noise suppression effect. An electric power control apparatus and a vehicle including the same are provided.

  According to this invention, the power control device is a power control device capable of transferring power between a power storage device mounted on a vehicle and an electric load or a power source outside the vehicle, the plurality of AC rotating electric machines, Inverter, plug, power line pair, control unit, common mode choke coil, and line bypass capacitor. Each of the plurality of AC rotary electric machines includes a star-connected multiphase winding as a stator winding. The plurality of inverters are provided corresponding to the plurality of AC rotating electric machines, and are controlled by a pulse width modulation method. The plug can be connected to an electrical load or a power source. The power line pair is disposed between the neutral point of the multiphase winding of two AC rotating electrical machines among the plurality of AC rotating electrical machines and the plug. The control unit is configured to transfer power between the power storage device and the electric load or power source by controlling an inverter corresponding to the two AC rotating electric machines. The common mode choke coil is disposed in the power line pair. The line bypass capacitor is connected between the power line pair and the vehicle ground between the common mode choke coil and the plug.

  In the present invention, between a power storage device and an electric load or power source outside the vehicle via a power line pair connected to a neutral point of a multiphase winding of two AC rotating electric machines among a plurality of AC rotating electric machines. Electricity is exchanged. Since the line bypass capacitor is provided in the power line pair together with the common mode choke coil, the common mode choke coil and the line bypass capacitor can share the suppression of the common mode voltage generated according to the high frequency switching of the inverter. Therefore, according to the present invention, the common mode voltage can be sufficiently suppressed, and the common mode choke coil can be reduced in size. Also, since the line bypass capacitor is arranged on the electric load or power supply side with respect to the common mode choke coil, the impedance of the common mode choke coil is increased with respect to the frequency of the common mode voltage, and the return line impedance to the vehicle ground Is designed so that most of the inverter common mode voltage is applied to the common mode choke coil and the load neutral point potential can be suppressed to a low value. Therefore, according to the present invention, a desired suppression effect can be obtained over a wide range of changes in the common mode impedance of the load.

  Further, according to the present invention, the power control device is a power control device capable of transferring power between a power storage device mounted on a vehicle and an electric load or power source outside the vehicle, and a plurality of AC rotating electric machines A plurality of inverters, a plug, a power line pair, a control unit, a common mode choke coil, and a line bypass capacitor. The power line pair is disposed between the neutral point of the multiphase winding of two AC rotating electrical machines among the plurality of AC rotating electrical machines and the plug. The common mode choke coil is disposed in the power line pair. The line bypass capacitor is connected between the power line pair and the vehicle ground between the common mode choke coil and the neutral point of the two AC rotating electric machines.

  In this invention, since the line bypass capacitor is disposed on the neutral point side of the AC rotating electric machine with respect to the common mode choke coil, most of the common mode voltage of the inverter is applied to the common impedance of the AC rotating electric machine, The common mode voltage across the bypass capacitor is low. Therefore, even when the load common mode impedance is small, the common mode applied to the common mode choke coil can be suppressed. Therefore, according to the present invention, the common mode voltage can be sufficiently suppressed, and the common mode choke coil can be further reduced in size.

  Preferably, the power control device further includes another line bypass capacitor. Another line bypass capacitor is connected between the power line pair and the vehicle ground between the common mode choke coil and the plug.

  In the present invention, since the line bypass capacitor is disposed on the neutral point side of the AC rotating electric machine with respect to the common mode choke coil, the common mode voltage applied to the common mode choke coil is suppressed. In addition, since another line bypass capacitor is arranged on the electric load or power supply side with respect to the common mode choke coil, the potential difference between the vehicle ground and the electric load or power supply is suppressed to a low value. Therefore, according to the present invention, the effect of suppressing the common mode voltage can be obtained over a wide range with respect to the change in the common mode impedance of the electric load or the power source.

  Preferably, the control unit includes a plurality of signal generation units. Each of the plurality of signal generation units generates a signal for turning on / off the switching element of the corresponding inverter. The signal generators corresponding to the two AC rotating electric machines generate signals using carrier waves whose phases are shifted from each other by approximately 180 °.

  In the present invention, the signal generators corresponding to the two AC rotating electric machines generate signals using carrier waves whose phases are shifted from each other by approximately 180 °, so that the common mode voltage generated by each inverter is canceled and the common The mode voltage is reduced. Therefore, according to the present invention, the common mode choke coil can be further reduced in size.

  More preferably, the power control apparatus further includes an inductor. The inductor is disposed on a power line connected to the neutral point of the AC rotating electrical machine having the smaller common mode impedance of the two AC rotating electrical machines.

  In the present invention, since the common mode impedance of the two AC rotating electric machines is balanced by providing the inductor, the common mode voltage is further reduced. Therefore, according to the present invention, the common mode choke coil can be further reduced in size.

  Preferably, the control unit includes a plurality of signal generation units each generating a signal for turning on / off the switching element of the corresponding inverter. Each of the inverters corresponding to the two AC rotating electric machines is a three-phase inverter. Each of the signal generators corresponding to the two AC rotating electric machines uses the first to third carrier waves whose phases are shifted from each other by approximately 120 °, and uses the U-phase switching element, the V-phase switching element of the corresponding inverter, and Signals for turning on / off the W-phase switching elements are generated.

  In the present invention, since the phase of the carrier wave is shifted by approximately 120 ° for each phase, the amplitude of the common mode voltage is reduced to 1/3 and the frequency is tripled. Therefore, according to the present invention, the common mode choke coil can be further reduced in size.

  According to the invention, the vehicle includes a wheel that receives a driving torque from at least one of the plurality of AC rotating electric machines, and any one of the power control devices described above. Therefore, according to the present invention, the common mode voltage can be sufficiently suppressed without hindering the downsizing of the vehicle.

  As described above, according to the present invention, common mode noise generated when power is transferred between the power storage device and an electric load or power source outside the vehicle is sufficiently suppressed, and the common mode choke coil is reduced in size. Can be As a result, common mode noise can be sufficiently suppressed without hindering downsizing of the vehicle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
1 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to Embodiment 1 of the present invention. Referring to FIG. 1, hybrid vehicle 100 includes an engine 2, motor generators MG <b> 1 and MG <b> 2, a power split mechanism 4, and wheels 6. Hybrid vehicle 100 includes power storage device B, inverters 10 and 20, electronic control unit (hereinafter referred to as "ECU") 30, smoothing capacitor C1, positive electrode line PL, and negative electrode line NL. And further comprising.

  Hybrid vehicle 100 further includes power lines ACL1 to ACL4, a smoothing capacitor C2, a common mode choke coil 40, a Y capacitor 50, an AC port 60, and a plug 70.

  Power split device 4 is coupled to engine 2 and motor generators MG1, MG2 to distribute power between them. For example, the power split mechanism 4 can be a planetary gear having three rotation shafts: a sun gear, a planetary carrier, and a ring gear. These three rotary shafts are connected to the rotary shafts of engine 2 and motor generators MG1, MG2, respectively. For example, engine 2 and motor generators MG1, MG2 can be mechanically connected to power split mechanism 4 by making the rotor of motor generator MG1 hollow and passing the crankshaft of engine 2 through its center.

  The power generated by the engine 2 is distributed by the power split mechanism 4 to the wheels 6 and the motor generator MG1. In other words, engine 2 is incorporated into hybrid vehicle 100 as a power source that drives wheels 6 and motor generator MG1. Motor generator MG1 operates as a generator driven by engine 2 and is incorporated in hybrid vehicle 100 as an electric motor that can start engine 2, and motor generator MG2 is a driving power for driving wheels 6. It is incorporated in the hybrid vehicle 100 as a source.

  Further, as will be described later, this hybrid vehicle 100 transfers power between the power storage device B and the load 90 by connecting a plug 70 to a load 90 that generally indicates an electric load or a power source outside the vehicle. can do.

  A positive electrode terminal of power storage device B is connected to positive electrode line PL, and a negative electrode terminal of power storage device B is connected to negative electrode line NL. Smoothing capacitor C1 is connected between positive electrode line PL and negative electrode line NL. Inverter 10 includes a U-phase arm 12, a V-phase arm 14, and a W-phase arm 16. U-phase arm 12, V-phase arm 14 and W-phase arm 16 are connected in parallel between positive electrode line PL and negative electrode line NL. The U-phase arm 12 includes switching elements Q11 and Q12 connected in series, the V-phase arm 14 includes switching elements Q13 and Q14 connected in series, and the W-phase arm 16 includes switching elements connected in series. It consists of elements Q15 and Q16. Diodes D11-D16 are connected in antiparallel to switching elements Q11-Q16, respectively. Inverter 20 includes a U-phase arm 22, a V-phase arm 24 and a W-phase arm 26. The configuration of the inverter 20 is the same as that of the inverter 10.

  In addition, as said switching element, IGBT (Insulated Gate Bipolar Transistor), power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor) etc. can be used, for example.

  Motor generator MG1 includes a Y-connected three-phase coil, and one end of each coil is connected to each other to form neutral point N1. Motor generator MG2 also includes a Y-connected three-phase coil, and one end of each coil is connected to each other to form neutral point N2. Power lines ACL1 and ACL2 are connected to neutral points N1 and N2, respectively.

  Common mode choke coil 40 is provided between power lines ACL 1 and ACL 2 and power lines ACL 3 and ACL 4 connected to AC port 60. Y capacitor 50 is provided between power lines ACL 3, ACL 4 and vehicle ground 80. Specifically, Y capacitor 50 includes capacitors C5 and C6, and capacitors C5 and C6 are connected between power lines ACL3 and ACL4 and vehicle ground 80. The plug 70 is connected to the AC port 60.

  The power storage device B is a rechargeable DC power source, and includes, for example, a secondary battery such as nickel metal hydride or lithium ion. Power storage device B supplies electric power to inverters 10 and 20 and is charged by receiving regenerative electric power output from inverters 10 and / or 20. Note that a large-capacity capacitor may be used as the power storage device B.

  Smoothing capacitor C1 smoothes voltage fluctuation between positive electrode line PL and negative electrode line NL. Capacitance C3 indicates the stray capacitance between positive line PL and vehicle ground 80. Capacitance C4 indicates the stray capacitance between negative line NL and vehicle ground 80. For example, a vehicle frame is used as the vehicle ground 80.

  Based on signal PWM1 from ECU 30, inverter 10 converts the DC voltage from power storage device B into a three-phase AC voltage and outputs the same to motor generator MG1. Inverter 10 also converts the three-phase AC voltage generated by motor generator MG1 using the power of engine 2 into a DC voltage and outputs the DC voltage to positive line PL and negative line NL.

  Inverter 20 converts the DC voltage from power storage device B into a three-phase AC voltage based on signal PWM2 from ECU 30, and outputs the converted three-phase AC voltage to motor generator MG2. Further, during regenerative braking of the vehicle, inverter 20 converts the three-phase AC voltage generated by motor generator MG2 using the rotational force of wheel 6 into a DC voltage and outputs it to positive electrode line PL and negative electrode line NL.

  Here, when charging of power storage device B is requested from a load 90 as a power supply (for example, a system power supply) outside the vehicle, inverters 10 and 20 are neutral via plug 70, AC port 60, and power lines ACL1-4. AC power applied to points N1 and N2 is converted to DC power and output to positive line PL and negative line NL, and power storage device B is charged. When power supply to load 90 as an AC electric load (for example, home appliance) is required, inverters 10 and 20 transfer an AC voltage having a predetermined frequency (for example, a commercial power supply frequency) between neutral points N1 and N2. And AC power is output from the plug 70 to the load 90.

  Each of motor generators MG1 and MG2 is a three-phase AC rotating electric machine, and includes, for example, a three-phase permanent magnet synchronous motor having a permanent magnet in a rotor. Motor generator MG <b> 1 is regeneratively driven by inverter 10, and outputs three-phase AC power generated using the power of engine 2 to inverter 10. Motor generator MG1 is driven by power by inverter 10 when engine 2 is started, and cranks engine 2. Motor generator MG <b> 2 is driven by power by inverter 20, and generates a driving force for driving wheels 6. Motor generator MG <b> 2 is regeneratively driven by inverter 20 during regenerative braking of the vehicle, and outputs three-phase AC power generated using the rotational force of wheel 6 to inverter 20.

  The ECU 30 generates a PWM signal for driving the inverter 10 by the pulse width modulation method, and outputs the generated PWM signal to the inverter 10 as a signal PWM1. ECU 30 also generates a PWM signal for driving inverter 20, and outputs the generated PWM signal to inverter 20 as signal PWM2.

  Here, when charging of power storage device B is requested from load 90 as an external power source, ECU 30 converts AC power from load 90 applied to neutral points N1 and N2 to DC power to store power storage device B. The inverters 10 and 20 are controlled so as to be charged. When power supply to the load 90 as an AC electric load is required, the ECU 30 controls the inverters 10 and 20 to generate an AC voltage between the neutral points N1 and N2 and output the AC voltage to the load 90.

  Smoothing capacitor C2 suppresses voltage fluctuation between power lines ACL1 and ACL2. That is, the smoothing capacitor C2 suppresses normal mode noise generated due to the high frequency switching of the inverters 10 and 20.

  The common mode choke coil 40 includes a ring-shaped ferrite core and two coils wound around the core in opposite directions (not shown). The filter composed of the common mode choke coil 40 and the Y capacitor 50 is designed so that the impedance of the common mode choke coil 40 is increased with respect to the frequency of the common mode voltage, and the return line impedance to the vehicle ground 80 is reduced. A large part of the mode voltage is applied to the common mode choke coil 40, the load neutral point potential is suppressed to a low value, and the common mode voltage is suppressed over a wide range of changes in the common mode impedance of the load. That is, both the common mode choke coil 40 and the Y capacitor 50 suppress common mode noise generated due to high frequency switching of the inverters 10 and 20.

  AC port 60 includes a relay for connecting / disconnecting power lines ACL3, ACL4 and plug 70, a voltage sensor for detecting voltage VAC between power lines ACL3, ACL4, and a current sensor for detecting current IAC flowing through power line ACL3 or ACL4. (Both not shown). When power is exchanged between the vehicle and load 90, AC port 60 turns on a relay in response to a command from ECU 30, and electrically connects plug 70 connected to load 90 with power lines ACL3 and ACL4. Connecting. Further, AC port 60 outputs detected values of voltage VAC and current IAC to ECU 30.

  Plug 70 is a connection terminal for electrically connecting hybrid vehicle 100 to load 90. As described above, load 90 collectively indicates an external power source for charging power storage device B or an electric load that receives power supply from hybrid vehicle 100, and is grounded to ground node 95.

Next, the cause of occurrence of the common mode voltage will be described.
FIG. 2 is a circuit diagram of a three-phase inverter. Referring to FIG. 2, motor generator MG viewed from neutral point NDC on the DC side is caused by a change in switching pattern of U, V, W phase arms connected in parallel between positive electrode line PL and negative electrode line NL. The voltage at the neutral point N, that is, the common mode voltage Vcom changes. Hereinafter, the switching pattern of each phase arm is defined as “1” when the upper arm is on (lower arm is off), and “0” when the lower arm is on (upper arm is off). Is defined. The switching patterns of the U, V, and W phase arms are denoted as u, v, and w, respectively, and the switching pattern of the three-phase inverter is denoted as (u, v, w).

  FIG. 3 is a diagram showing an equivalent circuit of the three-phase inverter in the first switching pattern. Referring to FIG. 3, when the switching pattern is (1, 1, 1), that is, when the upper arm of each phase arm is on, assuming that the DC side voltage is VDC, the common mode voltage Vcom is VDC. / 2.

  Although not particularly illustrated, when the switching pattern is (0, 0, 0), that is, when the lower arm is on for each phase arm, the common mode voltage Vcom is −VDC / 2.

  FIG. 4 is a diagram showing an equivalent circuit of the three-phase inverter in the second switching pattern. Referring to FIG. 4, when the switching pattern is (1, 1, 0), that is, when the upper arm is turned on in the U and V phase arms and the lower arm is turned on in the W phase arm, common mode voltage Vcom Becomes VDC / 6.

  Although not particularly illustrated, even when the switching pattern is (1, 0, 1) and (0, 1, 1), the common mode voltage Vcom is VDC / 6.

  FIG. 5 is a diagram showing an equivalent circuit of the three-phase inverter in the third switching pattern. Referring to FIG. 5, when the switching pattern is (1, 0, 0), that is, when the upper arm is turned on in the U-phase arm and the lower arm is turned on in the V and W-phase arms, the common mode voltage Vcom Becomes −VDC / 6.

  Although not particularly illustrated, even when the switching pattern is (0, 1, 0) and (0, 0, 1), the common mode voltage Vcom is −VDC / 6.

  Therefore, the common mode voltage Vcom has four levels of ± VDC / 6 and ± VDC / 2. When the carrier frequency is sufficiently higher than the frequency of the voltage command value, almost the same switching pattern appears for each carrier frequency. Therefore, the variation frequency of the common mode voltage Vcom is equal to the carrier frequency (for example, about 10 kHz).

  Thus, a common mode voltage having a four-level voltage waveform that varies with the carrier frequency is generated at the neutral point of the motor in accordance with the switching operation of the three-phase inverter. As shown in FIG. 1, power is transferred between the vehicle and a load 90 outside the vehicle via neutral points N1 and N2. In the first embodiment, the common mode choke coil 40 is used. And a Y capacitor 50 are provided to suppress the common mode voltage. Further, by providing the Y capacitor 50 in addition to the common mode choke coil 40, the common mode choke coil 40 can be reduced in size.

  Referring again to FIG. 1, in this first embodiment, Y capacitor 50 is connected between power lines ACL 3, ACL 4 and vehicle ground 80. That is, the Y capacitor 50 is disposed on the load 90 side with respect to the common mode choke coil 40.

  Here, the vehicle is obtained by appropriately designing the Y capacitor 50 so that the impedance of the common mode choke coil 40 is increased and the impedance of the Y capacitor 50 is decreased with respect to the fluctuation frequency of the common mode voltage (corresponding to the carrier frequency). By reducing the return line impedance to the ground 80, most of the inverter common mode voltage can be applied to the common mode choke coil 40, and the potential difference between the vehicle ground 80 and the load 90 can be reduced. Therefore, a common mode voltage suppressing effect can be obtained over a wide range with respect to the common mode impedance change of the load 90.

  FIG. 6 is a functional block diagram of ECU 30 shown in FIG. Referring to FIG. 6, ECU 30 includes first and second inverter control units 32 and 34 and a charge / discharge control unit 36. First inverter control unit 32 detects the detected value of voltage VDC between positive line PL and negative line NL, torque command value TR1 of motor generator MG1, and detected values of motor current I1 and rotation angle θ1 of motor generator MG1. receive. Then, first inverter control unit 32 generates a PWM signal for driving motor generator MG1 based on each signal, and outputs the generated PWM signal to inverter 10 as signal PWM1.

  Second inverter control unit 34 receives a detected value of voltage VDC, torque command value TR2 of motor generator MG2, and detected values of motor current I2 and rotation angle θ2 of motor generator MG2. Then, second inverter control unit 34 generates a PWM signal for driving motor generator MG2 based on the above signals, and outputs the generated PWM signal to inverter 20 as signal PWM2.

  Here, the first and second inverter control units 32 and 34 are charged and discharged when the power is transferred between the vehicle and the load 90 outside the vehicle via the neutral points N1 and N2. Are generated based on zero-phase voltage commands AC1 and AC2, respectively, and the generated signals PWM1 and PWM2 are output to inverters 10 and 20, respectively.

  Charging / discharging control unit 36, when signal CG instructing charging of power storage device B from load 90 is activated, based on voltage VAC and current IAC detected at AC port 60, motor generators MG1, MG2 and Zero phase voltage commands AC1 and AC2 are generated for causing inverters 10 and 20 to operate as a single phase PWM converter. Charging / discharging control unit 36 then outputs the generated zero-phase voltage commands AC1 and AC2 to first and second inverter control units 32 and 34, respectively.

  Charging / discharging control unit 36 uses motor generators MG1, MG2 and inverters 10, 20 as single-phase PWM inverters when signal DCG instructing power supply from neutral points N1, N2 to load 90 is activated. Zero phase voltage commands AC1 and AC2 for operation are generated. Charging / discharging control unit 36 then outputs the generated zero-phase voltage commands AC1 and AC2 to first and second inverter control units 32 and 34, respectively.

  Signals CG and DCG are activated, for example, when the user gives an instruction to start charging or start feeding when plug 70 is connected to load 90.

  FIG. 7 is a diagram showing a zero-phase equivalent circuit of inverters 10 and 20 and motor generators MG1 and MG2 shown in FIG. In each of the inverters 10 and 20 composed of a three-phase bridge circuit, there are eight patterns of combinations of on / off of six switching elements. Of the eight switching patterns, (1, 1, 1) and (0, 0, 0) have zero interphase voltage, and such a voltage state is called a zero voltage vector. For the zero voltage vector, the three switching elements in the upper arm are in the same switching state (all on or off), and the three switching elements in the lower arm are also in the same switching state. Therefore, in FIG. 7, the three switching elements of the upper arm of the inverter 10 are collectively shown as an upper arm 10A, and the three switching elements of the lower arm of the inverter 10 are collectively shown as a lower arm 10B. Similarly, the three switching elements of the upper arm of the inverter 20 are collectively shown as an upper arm 20A, and the three switching elements of the lower arm of the inverter 20 are collectively shown as a lower arm 20B.

  As shown in FIG. 7, this zero-phase equivalent circuit can be regarded as a single-phase PWM converter that receives single-phase AC power applied to neutral points N1 and N2 via power lines ACL1 and ACL2. Therefore, by changing the zero voltage vector in each of the inverters 10 and 20 and performing switching control so that the inverters 10 and 20 operate as an arm of a single-phase PWM converter, the AC power input from the power lines ACL1 and ACL2 is converted to DC. It can be converted into electric power and output to the positive electrode line PL and the negative electrode line NL.

  This zero-phase equivalent circuit can also be regarded as a single-phase PWM inverter that generates a single-phase AC voltage between the neutral points N1 and N2 using a DC voltage supplied from the positive electrode line PL and the negative electrode line NL. Therefore, the DC voltage supplied from the positive line PL and the negative line NL is changed by changing the zero voltage vector in each of the inverters 10 and 20 and performing switching control so that the inverters 10 and 20 operate as the arms of the single-phase PWM inverter. The electric power can be converted into AC power and supplied to the load 90.

  Although not particularly illustrated, resonance is generated between the Y capacitor 50 and the vehicle ground 80 for the purpose of reducing the resonance Q value of the LC circuit constituted by the common mode choke coil 40 and the Y capacitor 50 below the carrier frequency. A damping resistor may be provided.

  As described above, in the first embodiment, power is transferred between power storage device B and load 90 outside the vehicle via the power line pair connected to neutral points N1 and N2. Since the Y capacitor 50 is provided in the power line pair together with the common mode choke coil 40, the common mode choke coil 40 and the Y capacitor 50 can share the suppression of the common mode voltage generated in response to the high frequency switching of the inverters 10 and 20. . Therefore, according to the first embodiment, the common mode voltage can be sufficiently suppressed and the common mode choke coil 40 can be downsized.

  Since the Y capacitor 50 is disposed on the load 90 side with respect to the common mode choke coil 40, the impedance of the common mode choke coil 40 is increased with respect to the frequency of the common mode voltage, and the inverter common mode voltage is increased. When the portion is applied to the common mode choke coil 40, the potential difference between the vehicle ground 80 and the load 90 is suppressed to a low value. Therefore, according to the first embodiment, an effect of suppressing the common mode voltage can be obtained over a wide range with respect to the change of the common mode impedance of the load 90.

[Embodiment 2]
FIG. 8 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to the second embodiment. Referring to FIG. 8, hybrid vehicle 100A includes a Y capacitor 55 in place of Y capacitor 50 in the configuration of hybrid vehicle 100 in the first embodiment shown in FIG.

  Y capacitor 55 is provided between power lines ACL 1, ACL 2 and vehicle ground 80. Specifically, Y capacitor 55 includes capacitors C7 and C8, and capacitors C7 and C8 are connected between power lines ACL1 and ACL2 and vehicle ground 80. The Y capacitor 55 suppresses the common mode voltage on the power lines ACL1 and ACL2.

  Also in the second embodiment, as in the first embodiment, the common mode choke coil 40 and the Y capacitor 55 are provided between the neutral points N1 and N2 and the plug 70, and the common mode voltage is suppressed. Further, by providing the Y capacitor 55 in addition to the common mode choke coil 40, the common mode choke coil 40 can be reduced in size.

  Here, in the second embodiment, Y capacitor 55 is connected between power lines ACL 1, ACL 2 and vehicle ground 80. That is, the Y capacitor 55 is disposed on the neutral points N1 and N2 side with respect to the common mode choke coil 40. With such a configuration, the common mode voltage can be shared by the common mode impedance of motor generators MG1 and MG2, and the common mode voltage applied to common mode choke coil 40 is reduced.

  Therefore, according to the second embodiment, the common mode choke coil 40 can be further reduced in size.

[Embodiment 3]
FIG. 9 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to the third embodiment. Referring to FIG. 9, hybrid vehicle 100 </ b> B further includes Y capacitor 55 in the configuration of hybrid vehicle 100 in the first embodiment shown in FIG. 1.

  In other words, the potential difference between the vehicle ground 80 and the load 90 is reduced by the Y capacitor 50 disposed on the load 90 side with respect to the common mode choke coil 40, and the common mode impedance of the load 90 is changed over a wide range. A mode voltage suppressing effect is obtained. In addition, the common mode voltage applied to the common mode choke coil 40 is reduced by the Y capacitor 55 disposed on the neutral points N1 and N2 side with respect to the common mode choke coil 40.

  Therefore, according to the third embodiment, the load dependency of the common mode voltage suppression effect can be reduced, and the common mode choke coil 40 can be further downsized.

[Embodiment 4]
In the fourth embodiment, when power is transferred between the vehicle and a load 90 outside the vehicle via neutral points N1 and N2, the phases of the carrier signals of the inverters are shifted from each other by 180 °. In other words, the carrier signal of the inverter 20 is inverted with respect to the carrier signal of the inverter 10.

  The overall configuration of the hybrid vehicle according to the fourth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  Referring again to FIG. 6, ECU 30 in the fourth embodiment includes a second inverter control unit 34 </ b> A instead of second inverter control unit 34 in the configuration of the ECU in the first embodiment. When the second inverter control unit 34A receives the zero-phase voltage command AC2 from the charge / discharge control unit 36, the second inverter control unit 34A generates a carrier signal whose phase is shifted by 180 ° with respect to the carrier signal used in the first inverter control unit 32. The signal PWM2 is generated based on the zero-phase voltage command AC2. The other configuration of the second inverter control unit 34A is the same as that of the second inverter control unit 34.

  FIG. 10 is a diagram showing a switching pattern of each inverter in the fourth embodiment. Referring to FIG. 10, first inverter control unit 32 uses carrier signal CR1 to generate signal PWM1 based on zero-phase voltage command AC1 (= VAC / 2). In other words, the lower arm of each phase of inverter 10 is turned on at times t1 to t2 and t3 to t4 where zero phase voltage command AC1 is smaller than carrier signal CR1. On the other hand, before the time t1, when the zero-phase voltage command AC1 is greater than the carrier signal CR1, t2-t3 and after t4, the upper arm of each phase of the inverter 10 is turned on.

  Second inverter control unit 34A generates signal PWM2 based on zero-phase voltage command AC2 (= −VAC / 2) using carrier signal CR2 whose phase is shifted by 180 ° with respect to carrier signal CR1. That is, at the times t1 to t2 and t3 to t4 where the zero-phase voltage command AC2 is larger than the carrier signal CR2, each phase upper arm of the inverter 20 is turned on. On the other hand, before the time t1, when the zero-phase voltage command AC2 is smaller than the carrier signal CR2, t2-t3 and after t4, the lower arm of each phase of the inverter 20 is turned on.

  Then, since the relationship of VN1 = −VN2 is established between the instantaneous potential VN1 at the neutral point N1 and the instantaneous potential VN2 at the neutral point N2, the load electrically connected to the neutral points N1 and N2 When viewed from 90, the common mode voltage generated by the inverters 10 and 20 is canceled out and always becomes zero.

  Actually, since the common mode impedances of motor generators MG1 and MG2 are different from each other, the common mode voltage is not completely canceled and does not become zero. However, compared to the case where carrier signals CR1 and CR2 are in phase, The mode voltage is suppressed.

  Therefore, according to the fourth embodiment, the common mode choke coil 40 can be further reduced in size.

  In the above description, the carrier signal of each inverter is inverted in the configuration of the first embodiment. However, the carrier signal of each inverter may be inverted in the configuration of the second or third embodiment.

[Embodiment 5]
FIG. 11 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to the fifth embodiment. Referring to FIG. 11, this hybrid vehicle 100 </ b> C further includes an inductor 85 in the configuration of the hybrid vehicle in the fourth embodiment. Inductor 85 is provided on power line ACL1. Inductor 85 is provided to compensate for a difference in common mode impedance between motor generators MG1 and MG2.

  That is, motor generator MG1 mainly used for power generation is smaller in size than motor generator MG2 used for vehicle travel, and the common mode impedance of motor generator MG1 is smaller than the common mode impedance of motor generator MG2. In order to compensate for the difference, an inductor 85 is provided on power line ACL1 connected to neutral point N1 of motor generator MG1.

  By providing the inductor 85, the circuit constants on the motor generator MG1 side and the MG2 side are balanced, so that when the carrier signals of the inverters 10 and 20 are inverted with each other, the effect of canceling the common mode voltage is enhanced.

  Therefore, according to the fifth embodiment, the common mode voltage can be further suppressed. As a result, the common mode choke coil 40 can be further reduced in size.

  Although not particularly illustrated, the carrier signal of each inverter may be inverted in the configuration of the second or third embodiment, and the inductor 85 may be provided on the power line ACL1.

  When the common mode impedance of motor generator MG2 is smaller than the common mode impedance of motor generator MG1, inductor 85 is provided on power line ACL2 connected to neutral point N2 of motor generator MG2.

[Embodiment 6]
In the sixth embodiment, when power is transferred between the vehicle and a load 90 outside the vehicle via neutral points N1 and N2, in each inverter 10 and 20, the phase of the carrier signal is different for each phase. Are shifted from each other by 120 °.

  The overall configuration of the hybrid vehicle according to the sixth embodiment is the same as that of hybrid vehicle 100 shown in FIG.

  Referring to FIG. 6 again, ECU 30 in the sixth embodiment replaces first and second inverter control units 32 and 34 with the first and second inverter controls in the configuration of the ECU in the first embodiment, respectively. Part 32A, 34B is included.

  When the first inverter control unit 32A receives the zero-phase voltage command AC1 from the charge / discharge control unit 36, the first inverter control unit 32A uses the phase carrier signals whose phases are shifted from each other by 120 ° based on the zero-phase voltage command AC1. To generate the signal PWM1. Similarly, when the second inverter control unit 34B receives the zero-phase voltage command AC2 from the charge / discharge control unit 36, the zero-phase voltage command A signal PWM2 is generated based on AC2. The other configurations of the first and second inverter control units 32A and 34B are the same as those of the first and second inverter control units 32 and 34, respectively.

  FIG. 12 is a diagram showing a switching pattern of inverter 10 in the sixth embodiment. Referring to FIG. 12, first inverter control unit 32A uses a U-phase carrier signal CR1u, a V-phase carrier signal CR1v, and a W-phase carrier signal CR1w whose phases are shifted from each other by 120 °, and uses a zero-phase voltage command. A signal PWM1 is generated based on AC1 (= VAC / 2).

  That is, before time t2 when zero-phase voltage command AC1 is larger than U-phase carrier signal CR1u, and after t3-t8, t9, the U-phase upper arm of inverter 10 is turned on. Further, before time t4 when zero-phase voltage command AC1 is larger than V-phase carrier signal CR1v, at time t5 to t10, the V-phase upper arm of inverter 10 is turned on. Furthermore, the W-phase upper arm of inverter 10 is turned on after time t1 to t6 and t7 when zero-phase voltage command AC1 is larger than W-phase carrier signal CR1w.

  Therefore, at times t1 to t2, t3 to t4, t5 to t6, t7 to t8, and t9 to t10, the switching pattern of the inverter 10 is (1, 1, 1), and the potential VN1 at the neutral point N1 is VDC. / 2. In other time zones, the switching pattern of the inverter 10 is any one of (0, 1, 1), (1, 0, 1) and (1, 1, 0), and the potential VN1 at the neutral point N1. Becomes VDC / 6.

  FIG. 13 is a diagram showing a switching pattern of inverter 20 in the sixth embodiment. Referring to FIG. 13, second inverter control unit 34B uses zero-phase carrier signal CR2u, V-phase carrier signal CR2v, and W-phase carrier signal CR2w whose phases are shifted by 120 ° from each other, A signal PWM2 is generated based on AC2 (= −VAC / 2).

  That is, before time t14 when zero-phase voltage command AC2 is smaller than U-phase carrier signal CR2u and after t15, the U-phase lower arm of inverter 20 is turned on. Further, after time t11 to t16, t17 when the zero-phase voltage command AC2 is smaller than the V-phase carrier signal CR2v, the V-phase lower arm of the inverter 20 is turned on. Further, before the time t12 when the zero-phase voltage command AC2 is smaller than the W-phase carrier signal CR2w, and after t13 to t18, t19, the W-phase lower arm of the inverter 20 is turned on.

  Therefore, after times t11 to t12, t13 to t14, t15 to t16, t17 to t18, and t19, the switching pattern of the inverter 20 is (0, 0, 0), and the potential VN2 of the neutral point N2 is −VDC. / 2. In other time zones, the switching pattern of the inverter 20 is any one of (1, 0, 0), (0, 1, 0) and (0, 0, 1), and the potential VN2 at the neutral point N2 Becomes −VDC / 6.

  Therefore, the common mode voltage Vcom, which is ½ of the sum of the potentials VN1 and VN2 of the neutral points N1 and N2, has an amplitude of ± VDC / 6 and has three levels having a frequency three times the carrier frequency. It becomes a rectangular wave voltage.

  As described above, in the sixth embodiment, the common mode voltage applied to the common mode choke coil 40 is ３ that of the first embodiment and the frequency is tripled. The maximum magnetic flux density of the core of the coil 40 is reduced to 1/9. Therefore, according to the sixth embodiment, the core of the common mode choke coil 40 can be reduced to 1/3 the size of the first embodiment. Furthermore, the coil insulation of the common mode choke coil 40 can be expected to be simplified by reducing the common mode voltage.

  In the above description, the phase of each phase carrier signal of each inverter is shifted in the configuration of the first embodiment. However, in the configuration of the second or third embodiment, the phase of each phase carrier signal of each inverter is 120. It may be shifted by °.

  In each of the above embodiments, a converter that performs voltage conversion between power storage device B and inverters 10 and 20 may be provided between power storage device B and inverters 10 and 20. A known chopper circuit can be used as such a converter.

  In each of the above embodiments, the hybrid vehicle is provided with two motor generators. However, the present invention can also be applied to a hybrid vehicle provided with three or more motor generators. In that case, the above-described embodiments can be realized by using two motor generators of three or more motor generators and an inverter corresponding thereto.

  Further, in each of the above embodiments, the hybrid vehicle is of a series / parallel type in which the power of the engine 2 can be divided and transmitted to the axle and the motor generator MG1 by the power split mechanism 4. However, the present invention can also be applied to a so-called series type hybrid vehicle that uses engine 2 only for driving motor generator MG1 and generates the driving force of the vehicle only by motor generator MG2.

  Further, the present invention can also be applied to an electric vehicle that does not include the engine 2 and runs only by electric power, and a fuel cell vehicle that further includes a fuel cell as a power source in addition to a power storage device.

  In the above, load 90 corresponds to “an electric load or power supply outside the vehicle” in the present invention, and motor generators MG1 and MG2 correspond to “a plurality of AC rotating electric machines” in the present invention. Further, power lines ACL1, ACL2 (ACL3, ACL4) form “power line pair” in the present invention, and ECU 30 corresponds to “control unit” in the present invention.

  Furthermore, Y capacitors 50 and 55 correspond to the “line bypass capacitor” in the present invention, and Y capacitor 50 in the third embodiment corresponds to “another line bypass capacitor” in the present invention. Furthermore, the first and second inverter control units 32 (32A) and 34 (34A and 34B) correspond to “a plurality of signal generation units” in the present invention.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

1 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to Embodiment 1 of the present invention. It is a circuit diagram of a three-phase inverter. It is the figure which showed the equivalent circuit of the three-phase inverter at the time of a 1st switching pattern. It is the figure which showed the equivalent circuit of the three-phase inverter at the time of a 2nd switching pattern. It is the figure which showed the equivalent circuit of the three-phase inverter at the time of a 3rd switching pattern. It is a functional block diagram of ECU shown in FIG. It is the figure which showed the zero phase equivalent circuit of the inverter and motor generator which are shown in FIG. . FIG. 10 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to a second embodiment. FIG. 10 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to a third embodiment. It is the figure which showed the switching pattern of each inverter in Embodiment 4. FIG. FIG. 10 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle according to a fifth embodiment. It is the figure which showed the switching pattern of the inverter 10 in Embodiment 6. FIG. It is the figure which showed the switching pattern of the inverter 20 in Embodiment 6. FIG.

Explanation of symbols

  2 engine, 4 power split mechanism, 6 wheels, 10, 20 inverter, 10A, 20A upper arm, 10B, 20B lower arm, 12, 22 U phase arm, 14, 24 V phase arm, 16, 26 W phase arm, 30 ECU, 32, 32A 1st inverter control unit, 34, 34A, 34B 2nd inverter control unit, 36 charge / discharge control unit, 40 common mode choke coil, 50, 55 Y capacitor, 60 AC port, 70 plug, 80 Vehicle ground, 85 inductor, 90 load, 95 ground node, 100, 100A to 100C hybrid vehicle, B power storage device, C1, C2 smoothing capacitor, C3, C4 capacity, PL positive line, NL negative line, MG1, MG2 motor generator, N1, N2, NDC, N Neutral point, ACL1-ACL4 Power line, C5-C8 capacitor.

Claims (7)

A power control device capable of transferring power between a power storage device mounted on a vehicle and an electric load or power source outside the vehicle,
A plurality of AC rotating electric machines each including a star-connected multiphase winding as a stator winding;
A plurality of inverters provided corresponding to the plurality of AC rotating electric machines and controlled by a pulse width modulation method;
A plug connectable to the electrical load or the power source;
A pair of power lines disposed between the neutral point of the multiphase winding of the two AC rotating machines among the plurality of AC rotating machines and the plug;
A control unit configured to transfer power between the power storage device and the electric load or the power source by controlling an inverter corresponding to the two AC rotating electric machines;
A common mode choke coil disposed on the power line pair;
A power control apparatus comprising: a line bypass capacitor connected between the power line pair and a vehicle ground between the common mode choke coil and the plug. A power control device capable of transferring power between a power storage device mounted on a vehicle and an electric load or power source outside the vehicle,
A plurality of AC rotating electric machines each including a star-connected multiphase winding as a stator winding;
A plurality of inverters provided corresponding to the plurality of AC rotating electric machines and controlled by a pulse width modulation method;
A plug connectable to the electrical load or the power source;
A pair of power lines disposed between the neutral point of the multiphase winding of the two AC rotating machines among the plurality of AC rotating machines and the plug;
A control unit configured to transfer power between the power storage device and the electric load or the power source by controlling an inverter corresponding to the two AC rotating electric machines;
A common mode choke coil disposed on the power line pair;
A power control apparatus comprising: a line bypass capacitor connected between the power line pair and a vehicle ground between the common mode choke coil and the neutral point.   The power control apparatus according to claim 2, further comprising another line bypass capacitor connected between the power line pair and the vehicle ground between the common mode choke coil and the plug. The control unit includes a plurality of signal generation units each generating a signal for turning on / off a switching element of a corresponding inverter,
4. The power control according to claim 1, wherein the signal generation unit corresponding to the two AC rotating electric machines generates the signal using carrier waves whose phases are shifted by approximately 180 ° from each other. 5. apparatus.   The power control apparatus according to claim 4, further comprising an inductor disposed on a power line connected to a neutral point of the AC rotating electric machine having a smaller common mode impedance among the two AC rotating electric machines. The control unit includes a plurality of signal generation units each generating a signal for turning on / off a switching element of a corresponding inverter,
Each of the inverters corresponding to the two AC rotating electric machines is a three-phase inverter,
Each of the signal generation units corresponding to the two AC rotating electric machines uses the first to third carrier waves whose phases are shifted from each other by about 120 °, and uses the U-phase switching element and the V-phase switching element of the corresponding inverter. 4. The power control device according to claim 1, wherein the power control device generates a signal for turning on and off the W-phase switching element and the W-phase switching element. 5. A wheel that receives a driving torque from at least one of the plurality of AC rotating electric machines;
A vehicle provided with the electric power control apparatus of any one of Claims 1-6.

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