JP2010220455A - Charger for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charger for vehicle, which reduces loss while minimizing a cost increase. <P>SOLUTION: The charger for vehicle includes a motor 3, an inverter 1 for driving the motor 3, a motor 4 having a driving capability larger than that of the motor 3, an inverter 2 for driving the motor 4, and a connection which connects the inverter 1 and the motor 4 when the operation mode is the external charging mode otherwise disconnects the inverter 1 and the motor 4. The inverter 1 includes a switching element which is used for driving the motor 3 when the operation mode is not the external charging mode, and is subjected to switching control for voltage conversion when the operation mode is the external charging mode. The motor 4 includes a coil which is used as a stator coil when the operation mode is not the external charging mode, and is connected with the switching element by the connection when the operation mode is the external charging mode and used as a smoothing reactor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a charging device for a vehicle, and more particularly to a charging device for a vehicle equipped with a power storage device configured to be externally chargeable.

  2. Description of the Related Art In recent years, development of automobiles equipped with a power storage device such as an electric vehicle or a hybrid vehicle and a vehicle propulsion motor driven by the power storage device has become active as environmentally friendly vehicles. Japanese Patent Laid-Open No. 11-205909 (Patent Document 1) discloses a charging device for an electric vehicle used in such a vehicle.

  FIG. 11 is an equivalent circuit diagram of a charging device for an electric vehicle disclosed in Japanese Patent Laid-Open No. 11-205909.

  Referring to FIG. 11, this electric vehicle charging apparatus includes an inverter 101, a motor 102, a PWM control apparatus 103, a secondary battery 105, a diode module 106, a first relay 107, and a second relay. Relay 108.

  This charging device is a charging device using a driving motor and an inverter, and draws a line from the neutral point of the stator coil of the motor 102, and uses the motor's stator coil as a smoothing reactor. The secondary battery 105 can be charged.

JP-A-11-205909 JP 2004-229395 A JP-A-6-121408

  In the charging apparatus disclosed in Japanese Patent Laid-Open No. 11-205909, a high power (several hundred kW) inverter 101 for driving a vehicle propulsion motor is connected to a low power (several kW) from a commercial power source 104 for home use. ), There is a problem that the loss when charging from the outside is large.

  FIG. 12 is a waveform diagram showing the power supply voltage applied from the outside and the PWM control waveform of the inverter in the charging device shown in FIG.

  FIG. 13 is a diagram for explaining currents flowing through the upper arm and the lower arm of each phase of the inverter.

FIG. 14 is a waveform diagram for explaining the current shown in FIG.
In a charging device that charges using an inverter and a stator coil of a motor, conduction loss and switching loss occur in the inverter, and copper loss and iron loss occur in the motor. When the vehicle driving motor 102 and the inverter 101 as shown in FIG. 11 are used in a charging device, the switching elements such as IGBTs and MOSFETs included in the inverter have a high power rating (several hundred kW). As shown in FIGS. 13 and 14, the recovery current (reverse recovery current) of the freewheeling diode is larger than the charging current. For this reason, there is a problem that the switching loss at the time of charging is increased and the charging efficiency is lowered.

  The vehicle may be equipped with an inverter or motor with a low power rating (several kW) for an air conditioner or the like. However, when these are used in the charging device, the switching loss is reduced and the inverter loss is reduced, but the motor loss is increased. This is because a low-power rated motor has a thin winding, so that the winding resistance tends to increase and the copper loss increases.

  Therefore, with the conventional configuration, it has been difficult to realize a charging device that simultaneously reduces inverter loss and motor loss.

  On the other hand, the installation of a switching element or a reactor dedicated to external charging requires a mounting space and increases costs.

  The objective of this invention is providing the charging device for vehicles which reduced the loss, suppressing the increase in cost.

  In summary, the present invention is a vehicle charging apparatus, which has a first rotating electrical machine, a first inverter for driving the first rotating electrical machine, and a driving capability larger than that of the first rotating electrical machine. The second rotating electrical machine, the second inverter for driving the second rotating electrical machine, and the first inverter and the second rotating electrical machine are connected when the operation mode is the external charging mode; Is provided with a first connecting portion for disconnecting the first inverter and the second rotating electrical machine when the external charging mode is not set. The first inverter is used to drive the first rotating electric machine when the operation mode is not the external charging mode, and is switching-controlled for voltage conversion when the operation mode is the external charging mode. including. The second rotating electrical machine is used as a stator coil when the operation mode is not the external charging mode, and is used as a smoothing reactor connected to the switching element by the first connecting portion when the operation mode is the external charging mode. Including coils.

  Preferably, the vehicle charging device includes a diode bridge for full-wave rectification of an AC power supply external to the vehicle, and a DC voltage rectified by the diode bridge when the operation mode is an external charging mode. And a second connection section for separating the diode bridge and the voltage conversion circuit when the operation mode is not the external charging mode.

  Preferably, a diode module provided between the positive power supply line and the negative power supply line of the first inverter and in which two diodes are connected in series, and when the operation mode is the external charging mode, the connection point of the two diodes is external When the operation mode is not the external charge mode, a second connection unit that disconnects the connection point from the external power supply is further provided.

  Preferably, when the operation mode is the external charging mode, the first connecting unit connects the first inverter and the second rotating electric machine with an AC power supply outside the vehicle interposed. The first connecting portion includes a first relay that connects one electrode of the AC power source to the first inverter, and a second relay that connects the other electrode of the AC power source to the coil of the second rotating electrical machine.

  Preferably, the first inverter includes a multi-phase arm. The vehicle charging device further includes a control unit that performs switching control of the plurality of arms of the first inverter. The control unit performs switching control of the first arm of the plurality of phases when the operation mode is the external charging mode, and the first connection unit performs the switching control when the operation mode is the external charging mode. One arm is connected to the neutral point of the stator coil of the second rotating electrical machine.

  ADVANTAGE OF THE INVENTION According to this invention, the charging device for vehicles which reduced the inverter loss and the motor loss simultaneously can be provided, suppressing the increase in cost.

It is the circuit diagram which showed the structure of the charging device for vehicles of Embodiment 1 of this invention. It is the figure which showed the control waveform of each inverter of the charging device of FIG. FIG. 2 is a diagram showing a current path when charging is performed from the outside in the charging device of FIG. 1. It is the figure which showed the electric current which flows into the inverter 1 of FIG. It is the figure which showed the waveform of the electric current shown in FIG. 4 in contrast with the conventional waveform shown in FIG. FIG. 6 is a circuit diagram showing a configuration of a vehicle charging device according to a second embodiment. It is an operation | movement waveform diagram at the time of charge of the charging device shown in FIG. FIG. 5 is a circuit diagram showing a configuration of a charging device for a vehicle in a third embodiment. It is a wave form diagram for demonstrating control of the charging device for vehicles shown in FIG. FIG. 10 is a diagram showing a current path during charging in the third embodiment. 1 is an equivalent circuit diagram of a charging device for an electric vehicle disclosed in Japanese Patent Laid-Open No. 11-205909. FIG. 12 is a waveform diagram showing a power supply voltage applied from the outside and a PWM control waveform of the inverter in the charging device shown in FIG. 11. It is a figure for demonstrating the electric current which flows into the upper arm and lower arm of each phase of an inverter. It is a wave form diagram for demonstrating the electric current shown in FIG.

  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]
FIG. 1 is a circuit diagram showing a configuration of a vehicle charging apparatus according to Embodiment 1 of the present invention.

  Referring to FIG. 1, a vehicle equipped with the charging device of Embodiment 1 includes inverters 1 and 2, motors 3 and 4, PWM control devices 5 and 6, secondary battery 8, and diode bridge 9. Relays 10-12 and power lines 13-15.

  The inverter 1 and the motor 3 are for low power, and are, for example, electric compressors built in an air conditioner to which a power supply voltage is supplied from the secondary battery 8. On the other hand, the inverter 2 and the motor 4 are for high power, for example, for driving wheels to propel the vehicle.

  When the vehicle is traveling, the relays 10, 11, and 12 are controlled to be in an open state. In this state, the inverter 1 is used to drive the motor 3, and the inverter 2 is used to drive the motor 4.

  When charging the secondary battery 8 when returning home or the like, the external power source 7 is connected to the charging device of the vehicle. At this time, the relays 10, 11, and 12 are all controlled to be in a conductive state. When a voltage of, for example, 100 V AC is applied from the power source 7, the diode bridge 9 converts the voltage into DC. The voltage from the diode bridge 9 is converted into a charging voltage for the secondary battery 8 by a voltage converter constituted by a W-phase reactor of the motor 4 and a U-phase arm of the inverter 1.

  The vehicle charging device shown in FIG. 1 includes a motor 3, an inverter 1 for driving the motor 3, a motor 4 having a driving capability larger than that of the motor 3, an inverter 2 for driving the motor 4, and an operation. When the mode is the external charging mode, the inverter 1 and the motor 4 are connected, and when the operation mode is not the external charging mode, the inverter 1 and the motor 4 are disconnected. Inverter 1 includes a switching element that is used to drive motor 3 when the operation mode is not the external charging mode, and that is switching-controlled for voltage conversion when the operation mode is the external charging mode. The motor 4 includes a coil that is used as a stator coil when the operation mode is not the external charging mode, and is used as a smoothing reactor that is connected to the switching element by the connecting portion when the operation mode is the external charging mode.

FIG. 2 is a diagram showing control waveforms of the inverters of the charging apparatus of FIG.
FIG. 3 is a diagram showing a current path when charging is performed from the outside in the charging apparatus of FIG.

  2 and 3, the W-phase input terminal of the motor 4 for high power and the + side terminal of the diode bridge 9 are connected by the relay 11, and the neutral point of the motor 4 and the low power terminal are used. A U-phase input terminal of a certain motor 3 is connected by a relay 11. The negative terminal of the secondary battery and the negative terminal of the diode bridge 9 are connected by a relay 12.

  PWM modulation is performed only for the phase where the neutral point of the motor 4 is connected to the motor 3 (the U phase in FIGS. 1 and 3), and the other phases (V phase, W phase) of the inverter 1 and the upper and lower phases of the three phases of the inverter 2 All arms are stopped (OFF state). Thus, as shown in FIG. 3, the charging current path is as follows: power source 7 → diode bridge 9 → W-phase coil of motor 4 → neutral point of motor 4 → U-phase arm of inverter 1 → secondary battery 8.

  Since a low impedance current path is formed by the power line 13 connected from the neutral point of the motor 4 to the U-phase input terminal of the inverter 1, no current flows in the U-phase and V-phase coils of the motor 4. The U-phase and V-phase return diodes of the inverter 2 are not energized.

  Further, the input end of the W-phase coil of the motor 4 is stabilized at the potential of 100 V of the power source 7 by the action of the diode bridge 9, so that the W-phase return diode of the inverter 2 is not energized.

FIG. 4 is a diagram showing a current flowing through the inverter 1 of FIG.
FIG. 5 is a diagram showing the waveform of the current shown in FIG. 4 in contrast to the conventional waveform shown in FIG.

  The inverter 1 is used for an electric compressor of an air conditioner, for example, and is suitable for a smaller electric power than the inverter 2 that drives a motor for vehicle propulsion. Therefore, as shown in FIG. The switching loss is also reduced by reducing the switching time and the switching time.

  Further, since the coil of the high power motor 4 having a small winding resistance is used as a smoothing reactor, the motor loss is also reduced. Thus, by providing the relays 10, 11, and 12 and changing the connection at the time of charging, it becomes possible to perform charging while simultaneously reducing inverter loss and motor loss.

[Embodiment 2]
FIG. 6 is a circuit diagram showing a configuration of the vehicle charging device of the second embodiment.

  The charging device shown in FIG. 6 includes a diode module 9A in place of the diode bridge 9 in the configuration of the charging device shown in FIG. Relay 11 connects one electrode of power supply 7 and the W-phase coil of motor 4. The relay 12 connects the other electrode of the power source 7 and the midpoint of the diode module 9A.

  In the first embodiment, a diode bridge (full wave rectification) is used, but in the second embodiment, a diode module 9A connected in parallel with the inverter 1 is used.

FIG. 7 is an operation waveform diagram at the time of charging of the charging device shown in FIG.
As shown in FIG. 7, PWM modulation is performed only on the U phase of the inverter 1 in which the neutral point of the motor 4 is connected by a relay 10, and the other phase (V phase, W phase) of the inverter 1 and the three phases of the inverter 2 All arms are controlled to the off state.

  That is, when the voltage of the external power supply 7 is positive, a current flows through the diode of the lower arm of the diode bridge 9A as shown in FIG. 6, and when the voltage of the external power supply 7 is negative, the upper arm of the diode bridge 9A is shown. Current flows through the diode.

  By controlling in this way, the charging device of the second embodiment can achieve the same effects as those of the first embodiment.

[Embodiment 3]
FIG. 8 is a circuit diagram showing the configuration of the vehicle charging device of the third embodiment.

  Referring to FIG. 8, the vehicle charging device of the third embodiment includes relays 11 </ b> B and 12 </ b> B instead of diode bridge 9 and relays 10 to 12 in the configuration of the vehicle charging device shown in FIG. 1. Relay 11 </ b> B connects the midpoint of the U-phase arm of inverter 1 to one electrode of external power supply 7. Relay 12 </ b> B connects the neutral point of the stator coil of motor 4 to the other electrode of external power supply 7. That is, the configuration shown in FIG. 8 does not use a diode bridge or a diode module, but such a charging system has the same effect as in the first and second embodiments.

  As shown in FIG. 8, one end of the external power source 7 is connected to the U-phase input terminal of the motor 3 for low power by a relay 11B, and the other end of the external power source 7 is the neutral point of the motor 4 for high power. Connect to.

  FIG. 9 is a waveform diagram for explaining control of the vehicle charging device shown in FIG. Referring to FIGS. 8 and 9, only the U phase of inverter 1 is subjected to PWM modulation, and the other phase (V phase, W phase) of inverter 1 and the upper and lower arms of the three phases of inverter 2 are controlled to be in the OFF state. The inverter 2 may be switched according to the polarity of the external power source 7.

FIG. 10 is a diagram showing a current path during charging in the third embodiment.
By performing the control as shown in FIG. 9, a current flows through the current path as shown in FIG. That is, when the voltage of the external power supply 7 is positive, a current flows through the freewheeling diode of the lower arm of the inverter 2 as shown in FIG. 10, and when the voltage of the external power supply 7 is negative, the current of the inverter 2 is not shown. Current flows through the upper arm freewheeling diode. The diode of the inverter 2 functions in the same manner as the diode bridge 9A shown in FIG.

  The free-wheeling diodes of the upper and lower arms of the inverter 2 only switch at the frequency (50 Hz or 60 Hz) of the external power source 7, and the switching loss in this portion is small. Further, since the leakage inductance of the three-phase coil of the high-power motor 4 having a small winding resistance is used as the smoothing reactor, the motor loss is also small.

  As described above, in the present embodiment, switching control is performed by a low power inverter for in-vehicle equipment such as an air conditioner, and a coil of a high power motor for driving a vehicle is used as a smoothing reactor. As a result, the circuit configuration is such that the current of the freewheeling diode of the high power inverter is not energized. As a result, the inverter loss was excessive in the charging device that diverted the high-power motor or inverter mounted on the vehicle, and the motor loss was excessive in the charging device that diverted the low-power motor or inverter. By diverting a high-power motor as a smoothing reactor and performing switching control with a low-power inverter, it is not necessary to add a switching element or reactor dedicated to charging, and power loss can be reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 2 inverters, 3 and 4 motors, 5 and 6 PWM control device, 7 power supplies, 8 secondary batteries, 9 diode bridges, 9A diode modules, 10, 11, 11B, 12, 12B relays, 13 to 15 power lines.

Claims (5)

A first rotating electrical machine;
A first inverter for driving the first rotating electrical machine;
A second rotating electric machine having a driving capability larger than that of the first rotating electric machine;
A second inverter for driving the second rotating electrical machine;
When the operation mode is the external charging mode, the first inverter and the second rotating electric machine are connected, and when the operation mode is not the external charging mode, the first inverter and the second rotating electric machine are connected. A first connecting portion for separating the rotating electrical machine of
The first inverter is used to drive the first rotating electric machine when the operation mode is not the external charge mode, and for voltage conversion when the operation mode is the external charge mode. Including switching elements that are switching controlled,
The second rotating electrical machine is used as a stator coil when the operation mode is not the external charging mode, and when the operation mode is the external charging mode, the second rotating electrical machine is connected to the switching element by the first connection portion. A vehicle charging device including a coil connected and used as a smoothing reactor. A diode bridge for full-wave rectification of the AC power supply outside the vehicle;
When the operation mode is the external charging mode, a DC voltage rectified by the diode bridge is applied to a voltage conversion circuit including the coil and the first inverter, and the operation mode is the external charging mode. 2. The vehicle charging device according to claim 1, further comprising a second connection portion that disconnects the diode bridge and the voltage conversion circuit when there is no battery. A diode module provided between a positive power supply line and a negative power supply line of the first inverter and having two diodes connected in series;
When the operation mode is the external charging mode, the connection point of the two diodes is connected to an external power source, and when the operation mode is not the external charging mode, the connection point and the external power source are disconnected. The vehicle charging device according to claim 1, further comprising a second connection portion. When the operation mode is an external charging mode, the first connection unit connects the first inverter and the second rotating electrical machine with an AC power supply outside the vehicle interposed therebetween,
The first connection portion is
A first relay connecting one electrode of the AC power source to the first inverter;
The vehicle charging device according to claim 1, further comprising: a second relay that connects the other electrode of the AC power supply to the coil of the second rotating electrical machine. The first inverter includes a multi-phase arm;
The vehicle charging device includes:
A control unit that performs switching control of the arms of the plurality of phases of the first inverter;
The control unit performs switching control of a first arm of the plurality of arms when the operation mode is an external charging mode;
The said 1st connection part connects the said 1st arm and the neutral point of the said stator coil of the said 2nd rotary electric machine, when the said operation mode is an external charge mode, The Claim 1 characterized by the above-mentioned. Vehicle charging device.

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