JP7279329B2 - Charge control method and charge control device - Google Patents

Description

The present invention relates to a charging control method and a charging control device.

Patent Document 1 discloses a charging device in which a switching element included in an inverter for driving a motor is also used as a switching element for charging the AC power in an electric vehicle in which an in-vehicle battery can be charged with AC power supplied from an external power supply. It is This charging device is configured such that a switching element is provided between the motor and the inverter so that the motor does not rotate when the switching element is operated during charging, and current does not flow through the motor during charging.

Japanese Patent No. 5874990

However, when the motor is driven, it is necessary to pass a large current necessary for driving the motor, so the switch element installed between the motor and the inverter must be large in size and costly to cope with the large current. There's a problem.

According to the present invention, when a switching element included in an inverter for driving a motor is also used as a switching element for charging AC power, the switching element is not required to be installed between the motor and the inverter. It is an object of the present invention to provide a technology capable of avoiding current flow.

A charging control method according to the present invention is arranged between a battery, a motor, an inverter that converts the DC power of the battery into AC power and supplies it to the motor, and a high voltage terminal and a low voltage terminal on the battery side of the inverter. and a smoothing capacitor, further comprising an external power supply terminal, wherein the inverter converts AC power supplied to the external power supply terminal into DC power and supplies the DC power to the battery. A smoothing capacitor is composed of at least two capacitors connected in series. When charging the battery, all the output terminals on the motor side of the inverter are connected to the first terminal of the external power supply terminal, and the part of the smoothing capacitor that becomes the intermediate potential is connected to the second terminal of the external power supply terminal. By synchronously operating the switching elements of a plurality of phases constituting the inverter , the AC power from the external power supply is converted into DC power so that the line voltage between the phases of the motor becomes zero .

According to the present invention, alternating-current power from an external power supply is converted into direct-current power by synchronously operating switching elements of a plurality of phases that constitute an inverter. As a result, the line-to-line voltage of the motor during charging can be reduced to 0, so that current flow to the motor during charging can be avoided without installing a switch element between the motor and the inverter. be able to.

FIG. 1 is a schematic configuration diagram showing the configuration of the motor control system of the first embodiment. FIG. 2 is a diagram for explaining the charging control method (pulse width modulation control) of the first embodiment. FIG. 3 is a timing chart for explaining the charging control method (switching frequency control) of the first embodiment. FIG. 4 is a diagram showing static characteristics of the switching element (power semiconductor element) of the first embodiment. FIG. 5 is a schematic configuration diagram showing the configuration of the motor control system of the second embodiment. FIG. 6 is a schematic configuration diagram showing the configuration of the motor control system of Modification 1. As shown in FIG. FIG. 7 is a schematic configuration diagram showing the configuration of the motor control system of Modification 2. As shown in FIG.

[First embodiment]
FIG. 1 is a control block diagram showing a configuration example of a motor control system 100 to which a charging control device 21 according to the first embodiment of the invention is applied.

The motor control system 100 includes a charging control device 21 (hereinafter simply referred to as “charging device 21”), drives the motor 3 using the battery 1 as a power source, and uses power supplied from an external AC power supply 19. It is a system that can charge the battery 1 by The motor control system 100 is applied to, for example, hybrid vehicles and electric vehicles.

As illustrated, the motor control system 100 of this embodiment mainly includes a battery 1, an inverter 2, a motor 3, a smoothing capacitor 6, relays 7, 14, 16, a reactor 15, an EMI filter 17, and a , a filter capacitor 18 , a DCDC converter 20 , a drive circuit 10 , a control circuit 11 and a vehicle controller 12 .

The battery 1 is a high voltage battery and functions as a power source for supplying power to the motor 3 via the inverter 2 . In other words, battery 1 functions as a DC power supply that supplies DC power to inverter 2 .

The inverter 2 converts DC power from the battery 1 into three-phase AC power and supplies the three-phase AC power to the motor 3 according to a switching signal (pulse width modulation signal (PWM signal)) generated by the control circuit 11 to be described later. Also, the inverter 2 converts the single-phase AC power from the AC power supply 19 into DC power according to the switching signal generated by the control circuit 11 and supplies the DC power to the battery 1 . As illustrated, the inverter 2 is configured by a multi-phase power module 13 for performing power conversion between DC power and AC power.

The power module 13 of each phase (U-phase, V-phase, W-phase) includes three-phase power semiconductor elements (switching elements) Tr1, Tr3, and Tr5 in the upper arm and three-phase power semiconductor elements Tr2 and Tr4 in the lower arm. , Tr6. Each of the power semiconductor elements Tr1 to Tr6 is composed of, for example, an IGBT (Insulated Gate Bipolar Transistor), but in addition, a bipolar transistor, a MOSFET, or a GTO (Gate Turn-Off thyristor) may be used. . Diodes D1 to D6 are connected in antiparallel to the power semiconductor elements Tr1 to Tr6, respectively. When the drive circuit 10 receives a PWM (Pulse Wide Modulation) signal as a switching signal from the control circuit 11 described later, the power semiconductor devices Tr1 to Tr6 are opened and closed at a duty ratio according to the PWM signal by the drive circuit 10. be done. That is, the power module 13 is controlled according to switching control based on the PWM signal by the control circuit 11 .

As a result, the inverter 2 causes the motor 3 to generate a motor driving force corresponding to the torque command value T*, and converts the single-phase AC power from the AC power supply 19 into DC power at a desired switching frequency. can be supplied to Details of the operation of the inverter 2 according to this embodiment will be described later with reference to FIG. 2 and the like.

Between the high voltage terminal (positive electrode side of battery 1) and the low voltage terminal (negative electrode side of battery 1) on the battery 1 side of inverter 2, a DC voltage applied to the output voltage or input voltage of the inverter 2 is applied. A smoothing capacitor 6 for smoothing is arranged.

However, the smoothing capacitor 6 of this embodiment is configured by connecting two DC capacitors 6a and 6b in series. As a result, the smoothing capacitor 6 is provided with an intermediate potential point 6c between the two DC capacitors 6a and 6b. The intermediate potential point 6c provided in this manner is connected to a relay 14, which will be described later. Note that the smoothing capacitor 6 may be composed of at least two or more capacitors. For example, when four capacitors are connected in series, an intermediate potential point 6c is provided at an intermediate position between two capacitors on the high voltage terminal side and two capacitors on the low voltage terminal side. good too. It should be noted that the intermediate potential point 6c in the present embodiment does not necessarily have to be an intermediate potential in a strict sense, and is allowed to be slightly larger than the intermediate potential in a strict sense.

The external power supply terminal 22 has a first terminal 22a and a second terminal 22b, and is configured to electrically connect the charging device 21 and the AC power supply 19 existing outside the charging device 21 . In this embodiment, the first terminal 22 a is configured to connect to the hot side of the AC power supply 19 and the second terminal 22 b is configured to connect to the cold side of the AC power supply 19 .

The AC power supply 19 as an external power supply connected to the external power supply terminal 22 is, as described above, a single-phase AC power supply arranged outside the charging device 21, such as a general commercial power supply.

The relay 14 is provided on a line connecting the intermediate potential point 6c and the second terminal 22b, that is, a line connecting the intermediate potential point 6c and the cold side (ground side) of the AC power supply 19 as an external power supply. The relay 14 opens and closes so as to switch between a state (ON state) that conducts between the intermediate potential point 6c and the cold side of the AC power supply 19 and a state (OFF state) that electrically disconnects them.

Relay 16 connects three-phase (U-phase, V-phase, and W-phase) lines connecting output terminals 2u, 2v, and 2w of inverter 2 to respective phase windings of motor 3 and first terminal 22a. Each of the three-phase lines to be connected, that is, the output terminals 2u, 2v, and 2w (AC power output terminals) on the motor 3 side of the inverter 2 and the hot side (ungrounded side) of the AC power supply 19 as an external power supply are connected. provided for each of the three phase lines to be connected. The relay 16 opens and closes so as to switch between a state (on state) that conducts between the inverter 2 and the hot side of the AC power supply 19 and a state (off state) that electrically cuts them off.

In this embodiment, by switching on/off the relays 14 and 16 configured as described above, the operation mode of the motor control system 100 is the motor supplying the three-phase AC power output by the inverter 2 to the motor 3. It is possible to switch between a drive mode (relay 14: off, relay 16: off) and a charge mode (relay 14: on, relay 16: on) in which single-phase AC power output from AC power supply 19 is output to inverter 2. . The opening and closing of the relays 14 and 16 of this embodiment are configured to be controllable by a relay drive signal from the vehicle controller 12 .

Further, the relay 7 is in a state (on state) in which it conducts between the battery 1 and the inverter 2 and in a state (off state) in which it electrically disconnects between them according to a relay drive signal from the vehicle controller 12. open and close so that the In particular, when relay 7 receives an OFF command signal from vehicle controller 12 in the charging mode, relay 7 opens to electrically disconnect between battery 1 and inverter 2 .

DCDC converter 20 rectifies the DC power from inverter 2 and supplies it to battery 1 . More specifically, the DCDC converter 20 steps down the DC power (eg, 400 V) from the inverter 2 to a voltage (eg, 300 V) suitable for charging the battery 1 in the charging mode in which the relay 7 is turned off. and supply it to the battery 1. Note that the DCDC converter 20 of the present embodiment is a non-insulated type, and adopts a one-way type in which the input side and the output side are fixed, but is not limited to this. For example, a bidirectional DCDC converter 20 that is insulated and whose input side and output side can be interchanged may be employed. In this case, for example, when the motor 3 is not driven, in other words, when the motor drive mode is not selected, the power of the battery 1 is regenerated to the AC power supply 19 in a state where noise is further suppressed. be able to.

The reactor 15, the filter capacitor 18, and the EMI filter (Electro Magnetic Interference filter; electromagnetic interference filter) 17 are not affected by noise caused by switching of the switching elements of the inverter 2 in the charging mode described above. It is provided to suppress reaching the AC power supply 19 . In other words, the charging device 21 of the present embodiment is provided between the inverter 2 and the AC power supply 19 in order to remove noise generated in the inverter 2. A noise elimination circuit including a filter and an EMI filter 17 is provided.

Note that the reactor 15 of the present embodiment includes each of the three phases (U phase, V phase, and W phase) connecting the inverter 2 and the motor 3 and the hot side (ungrounded side) of the AC power supply 19 as an external power supply. is provided after the relay 16 (on the AC power supply 19 side) in the line connecting the . The filter capacitor 18 is provided between this line and a line connecting the intermediate potential point 6 c and the cold side of the AC power supply 19 . The EMI filter 17 is inserted in a line connecting the hot side of the inverter 2 and the AC power supply 19 and a line connecting the intermediate potential point 6 c and the cold side of the AC power supply 19 .

In the motor drive mode, the vehicle controller 12 transmits a relay drive signal (off command signal to turn off the relay 14 and the relay 16) to instruct the relays 14 and 16 to turn on/off, and also to operate the accelerator pedal by the driver. A torque command value T* corresponding to the operation amount (accelerator operation amount) is output to the control circuit 11 .

In addition, in the charging mode, the vehicle controller 12 transmits a relay drive signal (relay 14: ON, relay 16: ON command signal) commanding the relays 14 and 16 to turn ON/OFF, and the AC power source 19 It outputs to the control circuit 11 a charge command that serves as a trigger for controlling the inverter 2 so as to convert the AC power into DC power for supplying the battery 1 .

The control circuit 11 is a control circuit that controls driving of the power semiconductor elements Tr1 to Tr6 provided in the inverter 2. FIG. The configuration of the control circuit 11 of the present embodiment is realized by one or more controllers including various arithmetic/control devices such as a CPU, various storage devices such as ROM and RAM, and an input/output interface.

In the motor driving mode in which the relay 14 is in the OFF state (open state) and the relay 16 is in the OFF state (open state), the control circuit 11 controls the rotor position of the motor 3 obtained from a rotational position detector such as the resolver 4. position, the output current of the inverter 2 obtained from the current sensor 5, the DC voltage value (inverter voltage) on the battery 1 side (input side) of the inverter 2 obtained from the drive circuit 10, and the torque command from the vehicle controller 12 Based on the value T*, a known so-called current feedback control (current control system) generates a PWM signal for causing the motor 3 to output a desired torque. Pulse width modulation control for generating the PWM signal will be described later with reference to FIG.

On the other hand, in the charging mode in which the relay 14 is on (closed) and the relay 16 is on (closed), the control circuit 11 controls the battery 1 side (output side) of the inverter 2 obtained from the drive circuit 10 . ), the input current to the inverter 2 obtained from the current sensor 5, and the voltage value of the AC power supply input from the AC power supply 19, the voltage supplied to the battery 1 and the inverter 2 generates a PWM signal to control the input current to the desired value. Pulse width modulation control for generating the PWM signal will be described later with reference to FIG. 2(b).

In the charging mode, the control circuit 11 has an input power factor of 1 for the power (effective power) input to the inverter 2 with respect to the power (apparent power) input from AC power, that is, the input current to the inverter 2 is a sine wave. It is preferable to control the PWM signal so that As a result, power can be efficiently extracted from the AC power supply 19 and supplied to the battery 1, and generation of harmonic components due to reactive power can be suppressed. By controlling the inverter 2 in this way, it is possible to suppress the propagation of noise caused by the above harmonic components to the AC power supply 19 side in the charging mode.

The drive circuit 10 is a drive circuit that drives the power module 13 provided in the inverter 2 by pulse width modulation, which will be described later with reference to FIG. The drive circuit 10 includes an inverter voltage detector, a general circuit (gate drive circuit) for driving the power semiconductor elements Tr1 to Tr6 of the power module 13, and the power semiconductor elements Tr1 to Tr6 through the gate drive circuit. and a power source for applying a voltage to the gate of the Note that the DC voltage (inverter voltage) detected by the inverter voltage detector is sent to the control circuit 11 .

Note that the charging device 21 of this embodiment mainly includes an inverter 2 , a smoothing capacitor 6 , a drive circuit 10 , a control circuit 11 , relays 14 and 16 , and an external power supply terminal 22 .

The motor control system 100 of the present embodiment controls on/off (connection and disconnection) of the relays 14 and 16 based on the above-described configuration, and has a motor drive mode in which the motor 3 is driven using the battery 1 as a power source, and an external power source. A charging mode in which the battery 1 is charged using the AC power supply 19 as a power source can be realized.

Here, before explaining the pulse width modulation control when controlling the inverter 2, the subject of the present invention will be explained.

As described above, in the motor drive system, if the switching elements Tr1 to Tr6 constituting the inverter 2 for driving the motor are also used as switching elements for charging AC power, an unnecessary current may flow through the motor 3 during charging. need to be prevented. For this reason, conventionally, a relay (switch element) is provided between the motor 3 and the inverter 2, and by controlling the opening and closing of the relay, electrical connection between the motor 3 and the inverter 2 is interrupted during charging. known (see, for example, Patent Document 1).

However, since a large current (for example, several hundred amperes) required to drive the motor 3 flows between the motor 3 and the inverter 2, the size of the relay increases according to the magnitude of the current, and the system is However, there is a problem that the total cost of In view of such circumstances, the present invention aims at increasing the total cost of the system by increasing the size and cost of the relay for preventing unnecessary current from flowing to the motor 3 during charging. In other words, an object of the present invention is to prevent an increase in cost required for preventing unnecessary current from flowing to the motor 3 during charging. More specifically, the object of the present invention is to provide a technology capable of preventing unnecessary current from flowing to the motor 3 during charging without providing a relay between the motor 3 and the inverter 2 . . A control method for solving the problem will be described below.

Specifically, the charging control device 21 of the present embodiment connects the inverter 2 to the hot side of the AC power supply 19 and connects the intermediate potential point 6c to the cold side of the AC power supply 19 in the charging mode. , the above problem is solved by controlling the inverter 2 by the pulse width modulation control described below. Details of the pulse width modulation control will be described with reference to FIG.

The controller constituting the control circuit 11 is programmed to switch on/off the relays 14 and 16 in accordance with each control mode, and to execute pulse width modulation control described below in accordance with each control mode. ing.

FIG. 2 is a diagram for explaining the pulse width modulation control method of the inverter 2 in each operation mode (motor drive mode, charging mode) executed by the charging control device 21 of this embodiment. FIG. 2(a) shows the pulse width modulation during the motor driving mode, and FIG. 2(b) shows the pulse width modulation during the charging mode. 2(a) and 2(b), from the top, U-phase voltage, V-phase voltage, W-phase voltage, line-to-line voltage between U-phase and V-phase, line-to-line voltage between V-phase and W-phase, W-phase- The U-phase line voltage is shown.

First, the relay 14 is in an open (off) state and the relay 16 is in an open (off) state to ensure electrical continuity between the motor 3 and the inverter 2. Once disconnected, the motor drive mode is initiated.

As shown in FIG. 2(a), in the motor driving mode, the U-phase, V-phase, and W-phase voltages are generated in order to generate pulse-width-modulated line voltages so that a desired current flows in each phase. A voltage with a different pattern period is applied to each phase. As a result, a current corresponding to the line voltage is applied to each phase of the motor 3 so that the motor 3 can generate a desired torque.

On the other hand, when a charging command is input to the control circuit 11 and the relay 14 is closed (ON) and the relay 16 is closed (ON), conduction is established between the inverter 2 and the AC power supply 19, and the charging mode is entered. is started.

In the charge mode, pulse width modulation control is performed so that no current flows between the lines. That is, as shown in FIG. 2(b), the charging control device 21 of the present embodiment applies voltages of the same pattern to each of the U-phase, V-phase, and W-phase in the charging mode to Pulse width modulation control is performed so that the line voltage between each phase becomes zero. In other words, the charging control device 21 of the present embodiment executes the charging mode by controlling switching of the power modules 13 (power semiconductor elements) of the U-phase, V-phase, and W-phase to be synchronized. Voltages are applied to each of the U-phase, V-phase, and W-phase with the same pattern cycle, so that the voltage difference between the phases becomes 0, and the current flowing through each phase also becomes 0. By executing the pulse width modulation control in the charging mode in this way, it is possible to avoid the current from flowing to the motor 3 in the charging mode.

That is, according to the pulse width modulation control method of the present embodiment, even when the power semiconductor elements Tr1 to Tr6 constituting the inverter 2 provided for driving the motor are also used as switching elements for charging AC power, the motor 3 and the inverter 2, it is possible to prevent unnecessary current from flowing to the motor 3 in the charging mode without providing a switch element such as a relay. As a result, the motor control system 100 does not require a large relay that can handle a large current flowing between the motor 3 and the inverter 2, thereby suppressing an increase in the size and cost of the system. be able to.

Next, with reference to FIG. 3, the operation of the charge control device 21 in each operation mode (motor drive mode, charge mode), particularly control of the switching frequency of the inverter 2 will be described.

FIG. 3 is a diagram for explaining the operation of charging control device 21 in each operation mode. The horizontal axis represents time, and the vertical axis represents, from top to bottom, the operation mode, the open/close state of the relay 14 (between the intermediate potential point 6c and the cold side of the AC power supply 19), and the relay 16 (between the inverter 2 and the hot side of the AC power supply 19). ) and the switching frequency of the inverter 2 are shown.

When the relay 14 is open (OFF) and the relay 16 is open (OFF) so that the conduction between the inverter 2 and the AC power supply 19 is interrupted, the motor drive mode is started (see FIG. 3). (See “Commencement of Operation”). In the motor drive mode, the rotor position of the motor 3 obtained by the resolver 4 and the output current of the inverter 2 obtained by the current sensor 5 are fed back according to the torque command value T ^* so that desired torque is output. The drive of the motor 3 is controlled by pulse width modulation as described above. At this time, the switching frequency of the power module 13 provided in the inverter 2 is generally about several kHz to 10 kHz from the viewpoint of suppressing an increase in loss of the motor 3 and the inverter 2 while allowing the motor 3 to generate a desired torque. It is controlled to operate (in this embodiment it is assumed to be controlled at 10 kHz as shown).

Next, the operation in charge mode will be described. When a charge command is input to the control circuit 11 and the relay 14 is closed (ON) and the relay 16 is closed (ON), electrical continuity is established between the inverter 2 and the AC power supply 19, the charging mode is started. (See "Charging Start" in FIG. 3).

Here, if the inverter 2 is driven at the same switching frequency as in the motor drive mode even in the charge mode, the following problems will occur. That is, the filters and the like (reactor 15, filter capacitor 18, and EMI filter 17) constituting the noise elimination circuit of charging device 21 become larger as the frequency to be eliminated (suppressed) becomes smaller. In principle, the noise frequency to be suppressed by the noise elimination circuit corresponds to the switching frequency of the inverter 2 . Therefore, if the inverter 2 is driven at a switching frequency of about 10 kHz, which is the same as in the motor drive mode, the required size of the filter or the like that constitutes the noise elimination circuit becomes large.

That is, when configuring the charging device 21 that realizes both the motor driving mode and the charging mode in the motor control system 100, the power factor correction circuit (PFC circuit) composed of the inverter 2 and the smoothing capacitor 6 is simply shared. Only doing so would increase the size and cost of the components of the noise elimination circuit. Furthermore, when the size of the component parts of the noise elimination circuit increases, the large number of radiation fins provided to suppress the temperature rise of these parts impedes the flow of the coolant, resulting in an increase in the pressure loss of the coolant. There is also the problem of

Therefore, in the charging device 21 of the present embodiment, it is preferable to set the switching frequency when controlling the inverter 2 by the above-described pulse width modulation control in the charging mode to a higher frequency than in the motor driving mode. FIG. 3 shows an example in which the switching frequency is set to 60 kHz as a switching frequency that can suppress the size and cost of the components of the noise elimination circuit to an allowable level. Note that the upper limit of the switching frequency is not particularly set, and may be, for example, 100 kHz. As a result, when configuring the charging device 21 that realizes both the motor driving mode and the charging mode, it is possible to suppress an increase in the size and cost of the component parts of the noise elimination circuit.

In consideration of increasing the switching frequency during the charge mode, the power semiconductor elements Tr1 to Tr6 may be configured with semiconductor elements capable of switching at a frequency higher than that of the IGBTs described above. Specifically, the power semiconductor elements Tr1 to Tr6 may be configured using, for example, power semiconductor elements (eg, SiC-MOSFETs, etc.) using SiC (silicon carbide), GaN (gallium nitride), or the like.

As described above, even if the switching frequency in the charging mode is higher than that in the motor drive mode, it is possible to keep the loss low when converting the AC power from the AC power supply 19 into DC power. be. The reason will be described with reference to FIG.

FIG. 4 is a diagram showing an example of semiconductor characteristics (static characteristics) of the power semiconductor elements Tr1 to Tr6 included in the inverter 2 of this embodiment. The horizontal axis indicates voltage (collector-emitter voltage Vce), and the vertical axis indicates current (collector current Ic). Also, the loss that occurs in the inverter 2 is calculated by multiplying the flowing current by the voltage. That is, the loss that occurs during motor driving can be calculated by multiplying the maximum current during motor driving by the corresponding voltage (Vce(sat)2). Similarly, the loss that occurs during charging can be calculated by multiplying the maximum current during charging by the corresponding voltage (Vce(sat)1).

As shown in the figure, it can be seen that the loss during charging is smaller than the loss during motor driving. Here, in designing the motor control system 100, the power semiconductor devices Tr1 to Tr6 included in the inverter 2 are selected in consideration of the maximum value of the input/output current to the inverter 2. FIG. That is, since the power semiconductor elements Tr1 to Tr6 of the present embodiment are selected in consideration of the input/output current required for driving the motor, the operating point during charging has a sufficient margin with respect to its capability. Therefore, even if the switching frequency is increased as described above in the charging mode, the power semiconductor elements Tr1 to Tr6 have sufficient capacity, so that the AC power from the AC power supply 19 can be converted to DC power without increasing the loss. can be converted to

As described above, the charging control method performed by the charging control device 21 of the first embodiment includes the battery 1, the motor 3, the inverter 2 that converts the DC power of the battery 1 into AC power and supplies the AC power to the motor 3, and the high voltage of the inverter. A vehicle including a smoothing capacitor 6 arranged between a voltage terminal and a low voltage terminal further includes an external power supply terminal 22, and an inverter 2 converts AC power supplied to the external power supply terminal 22 into DC power. This is a charging control method for supplying to the battery 1 . The smoothing capacitor 6 is composed of at least two capacitors 6a and 6b connected in series. When charging the battery 1, all the output terminals 2u, 2v, 2w of the inverter 2 on the motor 3 side are connected to the first terminal 22a of the external power supply terminal 22, and the part that becomes the intermediate potential of the smoothing capacitor 6 is connected. (intermediate potential point 6c) and the second terminal 22b of the external power supply terminal 22 are connected, and the multi-phase switching elements (power module 13) constituting the inverter 2 are synchronously operated so that the alternating current from the AC power supply 19 is Converts electrical power to DC power. Further, according to the charging control device 21 of the first embodiment, when charging the battery 1, each line connecting all the output terminals 2u, 2v, 2w of the motor 3 of the inverter 2 and the motor 3 is connected to the first terminal 22a. connected to

As a result, even when the power semiconductor elements Tr1 to Tr6 constituting the inverter 2 provided for driving the motor are also used as switching elements for charging AC power, switch elements such as relays are provided between the motor 3 and the inverter 2. , it is possible to prevent unnecessary current from flowing through the motor 3 in the charging mode. As a result, a large relay for interrupting conduction between the motor 3 and the inverter 2 is not required, so that increases in size and manufacturing cost of the charging control device can be suppressed.

[Second embodiment]
A motor control system 200 according to the second embodiment will be described below. The motor control system 200 of this embodiment differs from the above embodiment in that the relay 16 is provided on the line connecting the neutral point 3c of the motor 3 and the first terminal 22a of the external power supply terminal 22. FIG. Differences from the above embodiment will be mainly described below with reference to FIG.

As described above, in the present embodiment, the relay 16 connects the line that connects the neutral point 3c of the motor 3 and the first terminal 22a, that is, connects the motor 3, the neutral point 3c, and the hot side of the AC power supply 19. It is provided on the line to Therefore, when the relay 16 is controlled to be closed (on) in the charging mode in this modified example, the inverter 2 and the AC power supply 19 are connected via the neutral point 3c of the motor 3 .

With this embodiment configured as described above, when the relay 16 is closed in the charging mode, the inductance component (so-called zero-phase inductance) of the motor 3 is reduced in the line connecting the inverter 2 and the AC power supply 19. It becomes possible to use. As a result, in the charging device 21 according to the above-described embodiment, the function of the reactor 15, which is a part of the noise elimination circuit, can be covered by the inductance component of the motor 3. Reactor 15 can be deleted.

Further, in this embodiment, since the connection between the inverter 2 and the AC power supply 19 is made through a single line through the neutral point 3c of the motor 3, only one relay 16 is required for the line. Therefore, the number of relays 16 can be reduced by two as compared with the above embodiment. That is, according to this embodiment, the number of parts can be further reduced and the cost can be further reduced as compared with the first embodiment.

Even in such a configuration, by controlling the inverter 2 by the same pulse width modulation control as in the above-described embodiment, it is not necessary to provide a switch element such as a relay between the motor 3 and the inverter 2. It is possible to avoid the current from flowing through the motor 3 during the charging mode.

As described above, according to the charging control device 21 of the second embodiment, when charging the battery 1, all the output terminals 2u, 2v, and 2w on the motor 3 side of the inverter 2 and the first terminal 22a of the external power supply terminal 22 are connected via the neutral point 3c of the motor 3. As a result, the inductance component of the motor 3 can be used in the line connecting the inverter 2 and the AC power supply 19, so that the number of parts including at least the reactor 15 can be reduced and the manufacturing cost can be reduced compared to the first embodiment. can be reduced.

[First modification]
A motor control system 300 of a first modified example as a modified example of the above embodiment will be described below. Differences from the above embodiment will be mainly described below with reference to FIG.

A motor control system 300 according to this modification includes a bidirectional non-insulated DCDC converter including a power module 13 and a reactor 24 instead of the DCDC converter 20 provided in the above embodiment. With such a configuration, the circuit configuration between the battery 1 and the inverter 2 can be made simpler and smaller, and the cost can be reduced. It should be noted that the relay 7 is operated by the vehicle controller 12 when it is determined that the battery 1 is not normal, such as when the battery 1 is in an electrical shortage state in which the amount of charge in the battery 1 is lower than a predetermined reference value, for example, in the motor drive mode. It is configured to be able to electrically disconnect between the battery 1 and the power module 13 by a drive signal.

Even with such a configuration, by controlling the inverter 2 by pulse width modulation control similar to that of the above-described embodiment, it is not necessary to provide a switch element such as a relay between the motor 3 and the inverter 2. It is possible to avoid the current from flowing through the motor 3 during the charging mode. The bidirectional non-insulated DCDC converter including the power module 13 can also function as a boost converter in the motor drive mode.

[Second modification]
Below, the motor control system 400 of the 2nd modification as a modification of the said embodiment is demonstrated. A motor control system 400 of this modification differs from the above-described embodiment in that the battery 1 can be charged using electric power supplied from a three-phase AC power supply 29 as an external power supply. Differences from the above embodiment will be mainly described below with reference to FIG.

As described above, in this modification, power for charging the battery 1 is supplied from the external three-phase (U-phase, V-phase, and W-phase) AC power supply 29 . Therefore, in this modified example, a power module 23 is added to the configuration according to the above embodiment. A third terminal 22 c is added to the external power supply terminal 22 to correspond to the external three-phase AC power supply 19 .

The power module 23 includes an upper arm power semiconductor element Tr9, a lower arm power semiconductor element Tr10, and diodes D9 and D10 connected in anti-parallel to these elements. In this modification, the intermediate point of the power module 23 and the third terminal 22c, that is, the intermediate point of the power module 23 and any one phase of the AC power supply 29 are connected.

That is, in this modification, each of the three phases (U-phase, V-phase, and W-phase) connecting the inverter 2 and the motor 3 is connected to an arbitrary one of the three phases of the AC power source 29, and the power The intermediate point of the module 23 is connected to any one of the three phases of the AC power supply 29, and the intermediate potential point 6c of the smoothing capacitor 6 is connected to any one of the three phases of the AC power supply 29. be.

The relays 16 are provided on three-phase lines connecting each phase of the inverter 2 to any one of the three phases of the AC power supply 29, and conduct between the inverter and the AC power supply 29. It opens and closes so as to switch between a state (ON state) that allows the electrical connection and a state (OFF state) that electrically disconnects them.

Also, the relay 14 connects a line connecting an intermediate point of the power module 23 and any one of the three phases of the AC power supply 29, and an intermediate potential point 6c of the smoothing capacitor 6 and the three phases of the AC power supply 29. are provided on the lines that connect any one phase of the inverter and the AC power supply 29, and switch between the state of conducting between the inverter and the AC power supply 29 (ON state) and the state of electrically disconnecting them (OFF state). to open and close.

As in the above embodiment, the relays 14 and 16 are both controlled to be open (OFF) in the motor driving mode, and both are controlled to be closed (ON) in the charging mode. .

In the charging mode, the power module 13 that constitutes the inverter 2 and the newly added power module 23 convert the three-phase AC power from the AC power supply 29 into DC power for charging the battery 1. driven to Thereby, the charging control device 21 can use the external three-phase AC power supply 29 connected to the external power supply terminal 22 as a power supply when charging the battery 1 .

Since the power module 23 operates only in the charging mode, it is not necessary to consider the current required to drive the motor 3 when selecting it. Therefore, since it is not necessary to deal with a large current for driving the motor, a compact and low-cost semiconductor can be applied to the power module 13 . Similarly, the current sensor 5 provided on the line connecting the intermediate point of the power module 13 and the AC power supply 29 only needs to consider the current flowing in the charging mode, so a small and low-cost current sensor is applied. be able to.

Even with such a configuration, it is not necessary to provide a switch element such as a relay between the motor 3 and the inverter 2 by controlling the inverter 2 in the charge mode by pulse width modulation control similar to that of the above embodiment. Therefore, it is possible to avoid current from flowing to the motor 3 during the charging mode.

The noise elimination circuit of this modified example is also configured to be compatible with the external three-phase AC power supply 19 . Specifically, the reactor 15 of the present embodiment is provided in each line after the relay 16 (on the side of the AC power supply 29) and after the relay 14, as illustrated. The filter capacitor 18 includes a line connecting each phase of the inverter 2 to any one of the three phases of the AC power source 29, an intermediate point of the power module 23, and one of the three phases of the AC power source 29. and a line connecting any one phase of the power module 23 and a line connecting any one of the three phases of the AC power supply 29 and the intermediate potential point of the smoothing capacitor 6 6 c and a line connecting an arbitrary one of the three phases of the AC power supply 29 , each is provided after the reactor 15 .

In addition, the EMI filter 17 is provided in the three lines that connect the inverter 2, the intermediate point of the power module 23, the intermediate potential point 6c of the smoothing capacitor 6, and the AC power supply 29 in the latter stage of the filter capacitor 18 (most external power supply terminal 22). (near the ).

Although the embodiments of the present invention and their modifications have been described above, the above embodiments and modifications merely show a part of the application examples of the present invention, and the technical scope of the present invention is limited to the above embodiments. It is not intended to be limited to a specific configuration. Moreover, the above-described embodiments and modifications thereof can be combined as appropriate.

For example, the motor control system 300 of Modification 1 is configured to support an external single-phase AC power supply 19, but may be configured to support an external three-phase AC power supply 29 as in Modification 3. .

Also, the configurations of the motor control systems 100-400 are not limited to those shown in FIGS. For example, the vehicle controller 12 does not necessarily have to control the opening and closing of the relays 14 and 16, and the control circuit 11 may control the opening and closing of the relays 14 and 16. FIG. Also, the control circuit 11 and the vehicle controller 12 do not necessarily have to be configured separately, and may be realized by a single integrated controller.

Moreover, the trigger for starting the charging mode is not limited to the charging command from the vehicle controller 12 described above. For example, the connection of the AC power supplies 19 and 29 to the external power supply terminal 22, that is, the detection of the AC power supply voltage may be used as a trigger to start the charging mode.

DESCRIPTION OF SYMBOLS 1... Battery 2... Inverter 2u, 2v, 2w... Output terminal 3... Motor 6... Smoothing capacitor 6a, 6b... Capacitor 6c... Intermediate electric potential point (the part used as an intermediate electric potential)
11... Control circuit (controller)
12... vehicle controller (controller)
14, 16...Relay (connection switching unit)
Tr1 to Tr6... Power semiconductor elements (switching elements)
22... External power supply terminal 22a... First terminal 22b... Second terminal

Claims (4)

a battery, a motor, an inverter that converts the DC power of the battery into AC power and supplies the AC power to the motor, and a smoothing capacitor that is arranged between a high voltage terminal and a low voltage terminal of the inverter on the battery side. , further comprising an external power supply terminal, wherein the inverter converts AC power supplied to the external power supply terminal into DC power and supplies the DC power to the battery,
The smoothing capacitor is composed of at least two capacitors connected in series,
When charging the battery,
connecting all the output terminals on the motor side of the inverter to a first terminal of the external power supply terminal, and connecting a portion of the smoothing capacitor that is an intermediate potential to a second terminal of the external power supply terminal;
AC power from the external power supply is converted into DC power so that the line voltage between the phases of the motor becomes 0 by synchronously operating the switching elements of the plurality of phases that constitute the inverter;
Charge control method. When charging the battery, each line connecting all the output terminals on the motor side of the inverter and the motor is connected to the first terminal.
The charging control method according to claim 1. When charging the battery, all the output terminals on the motor side of the inverter and the first terminal of the external power supply terminal are connected via the neutral point of the motor.
The charging control method according to claim 1. a battery, a motor, an inverter that converts the DC power of the battery into AC power and supplies the AC power to the motor, and a smoothing capacitor that is arranged between a high voltage terminal and a low voltage terminal of the inverter on the battery side. A charging control device further comprising an external power supply terminal, wherein the inverter converts AC power supplied to the external power supply terminal into DC power and supplies the DC power to the battery,
The smoothing capacitor is composed of at least two capacitors connected in series,
Connections between all output terminals of the inverter on the motor side and a first terminal of the external power supply terminal, and connections between a part of the smoothing capacitor having an intermediate potential and a second terminal of the external power supply terminal; a connection switching unit that switches non-connection;
A controller that controls the connection switching unit and the operation of the inverter,
The controller is
When charging the battery,
connecting all the output terminals on the motor side of the inverter to a first terminal of the external power supply terminal, and connecting a portion of the smoothing capacitor that is an intermediate potential to a second terminal of the external power supply terminal;
AC power from the external power supply is converted into DC power so that the line voltage between the phases of the motor becomes 0 by synchronously operating the switching elements of the plurality of phases that constitute the inverter;
charging controller.

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