JP2022144450A - Power conversion device - Google Patents

Abstract

To provide a power conversion device capable of charging a power source by adjusting voltage of a charging facility without providing a voltage adjusting device such as a step-up converter and a step-down converter.SOLUTION: A power conversion device 1 has: a power source 2; a first inverter 4 with a first upper arm element 8 and a first lower arm element 9 connected to the power source 2; a rotary electric machine 3 with coils 3u, 3v, and 3w whose ends are connected to the first inverter 4; and a second inverter 5 having a second upper arm element 11 and a second lower arm element 12, and to which the other ends of the coils 3u, 3v, and 3w are connected, and further has: a switch 16 selectively connecting or blocking a positive electrode of the power source 2 and a high potential side of the first upper arm element 8, and the high potential side of the second upper arm element 11; and a charging port 20 provided on a positive electrode side and a negative electrode side of the second inverter 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power converter that converts power output from a power supply.

Patent Literature 1 describes a power conversion device that converts and supplies power output from a power storage device to a motor provided as a driving force source for an electric vehicle, a hybrid vehicle, or the like. This motor is a three-phase AC motor, and includes an inverter that converts a DC current output from a power storage device into an AC current that flows through three-phase coils. This inverter is formed by three H-bridge configurations.

Japanese Patent Application Laid-Open No. 2009-303298

Vehicles such as electric vehicles and plug-in hybrid vehicles can be charged by supplying electric power to a rechargeable battery from a charging facility provided outside the vehicle. Such charging equipment includes, for example, household power sources and dedicated quick charging equipment, and the output voltage varies depending on the charging equipment. Therefore, in order to charge the rechargeable battery using charging equipment with different output voltages, it is necessary to step up or step down the voltage supplied to the vehicle from the charging equipment to match the voltage of the storage battery. Since the power conversion device described in Patent Document 1 does not have a function to change the voltage supplied from the charging equipment as described above and supply it to the rechargeable battery, a separate voltage adjustment device such as a step-up converter or a step-down converter is provided. is required, and there is a possibility that the size of the power conversion device including the voltage regulator becomes large.

The present invention has been made in view of the above technical problems, and can charge a power source by adjusting the voltage of a charging facility without separately providing a voltage adjusting device such as a boost converter or a step-down converter. An object of the present invention is to provide a power converter.

To achieve the above object, the present invention provides a power supply, a first upper arm element connected to the positive side of the power supply, a first lower arm element connected to the negative side of the first upper arm element, and the negative side of the power supply. a first inverter having an arm element; a rotating machine having a coil whose one end is connected to a connecting portion between the first upper arm element and the first lower arm element in the first inverter; a second upper arm element, the high potential side of which is connected to the low potential side of the second upper arm element, and the low potential side of which is connected to the negative electrode of the power supply and the low potential side of the first lower arm element; In a power conversion device comprising an arm element and a second inverter in which the other end of the coil is connected to a connection portion between the second upper arm element and the second lower arm element, the positive electrode of the power supply and a switch capable of selectively connecting and disconnecting the high potential side of the first upper arm element and the high potential side of the second upper arm element, and the positive side and negative side of the second inverter. and a charging port provided in the device.

Further, the present invention further includes a controller for controlling the switch, the first inverter, and the second inverter, wherein the controller has a charging power supply connected to the charging port and a voltage of the power supply and the voltage of the power supply. When the voltage of the charging power supply is the same, the switch is opened and the first upper arm element and the second upper arm element are brought into conduction so that the power supply and the charging power supply are connected. It may be configured to allow power transfer to and from a power source.

Further, the present invention further includes a controller for controlling the switch, the first inverter, and the second inverter, wherein the controller has a charging power supply connected to the charging port and a voltage of the power supply and the voltage of the power supply. When the voltage of the power source for charging is the same, power transmission between the power source and the power source for charging may be enabled by bringing the switch into a conducting state.

Further, the present invention further includes a controller for controlling the switch, the first inverter, and the second inverter, wherein the controller has a charging power source connected to the charging port, and the voltage of the power source is the above-described power source. When the voltage is higher than the voltage of the power supply for charging, the switch is opened, the second upper arm element is brought into conduction, and the first lower arm element is turned on and off, so that the power supply and the It may be configured to allow power transfer to and from a charging power source.

The present invention further includes a controller for controlling the switch, the first inverter, and the second inverter, wherein the controller has a charging power source connected to the charging port, and the voltage of the power source is the above-described power source. When the voltage is lower than the voltage of the power supply for charging, the switch is opened, the first upper arm element is brought into a conducting state, and the second lower arm element is turned on and off, so that the power supply and the It may be configured to allow power transfer to and from a charging power source.

According to this invention, the rotating machine can be controlled by controlling the first inverter and the second inverter. Further, when a charging power supply is connected to the charging port, the power converter can function as a step-up converter or a step-down converter by controlling the first inverter, the second inverter, or the switch. Therefore, it is not necessary to provide a voltage adjusting device for changing the charging voltage in the power conversion device for controlling the rotating machine, and the electric unit can be miniaturized.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram for demonstrating an example of the power converter device in embodiment of this invention. 4 is a flowchart for explaining an example of control for charging a rechargeable battery; FIG. 2 is an equivalent circuit diagram that simply shows a circuit state formed when the voltage of the rechargeable battery is higher than the voltage of the charging power supply; FIG. 2 is an equivalent circuit diagram that simply shows a circuit state formed when the voltage of the rechargeable battery is lower than the voltage of the charging power supply; FIG. 3 is an equivalent circuit diagram showing a simplified circuit state formed when the voltage of the rechargeable battery and the voltage of the charging power supply are the same; FIG. 4 is an equivalent circuit diagram simply showing another circuit state formed when the voltage of the rechargeable battery is higher than the voltage of the charging power supply; 5 is a graph showing a state in which, when the voltage of the rechargeable battery is higher than the voltage of the charging power supply, the voltage of the charging power supply is boosted and applied to the rechargeable battery. 5 is a graph showing a state in which the voltage of the charging power supply is stepped down to act on the rechargeable battery when the voltage of the rechargeable battery is higher than the voltage of the charging power supply.

FIG. 1 shows a configuration diagram for explaining an example of a power converter according to an embodiment of the invention. The power conversion device 1 shown in FIG. 1 converts electric power supplied between a storage battery 2 corresponding to the "power source" in the embodiment of the present invention and a motor 3 corresponding to the "rotating machine" in the embodiment of the present invention. It is something to do. The storage battery 2 is configured similarly to a storage battery provided in a conventional electric vehicle or hybrid vehicle. That is, the storage battery 2 is configured by connecting secondary batteries such as lithium-ion batteries and nickel-hydrogen batteries in series.

The motor 3 is configured similarly to a motor provided as a driving force source for conventional electric vehicles and hybrid vehicles. The motor 3 is an open-winding electric motor, and can be composed of an AC motor provided with coils of a plurality of phases of two or more. In the example shown in FIG. is composed of an AC motor such as a synchronous motor or an induction motor having three-phase coils 3u, 3v, and 3w.

Therefore, a first inverter 4 and a second inverter 5 are provided for converting the DC voltage of the storage battery 2 into AC voltage and applying the voltage to the motor 3 . A first terminal of the first inverter 4 is connected to the first positive bus line 6 of the storage battery, and a second terminal of the first inverter 4 is connected to the first negative bus line 7 of the storage battery 2 . The first inverter 4 is composed of a first upper arm switch (element) 8 and a first lower arm switch (element) 9 .

The first upper arm switch 8 is composed of a first switch Q1, a third switch Q3, and a fifth switch Q5 whose collectors, which are terminals on the high potential side, are connected to the first positive electrode bus line 6, respectively. The first lower arm switch 9 includes a second switch Q2 and a fourth switch Q2 having respective collectors connected to the respective emitters of the first upper arm switch 8 and having respective emitters connected to the first negative electrode bus 7. It is composed of a switch Q4 and a sixth switch Q6. That is, the collector of the second switch Q2 is connected to the emitter of the first switch Q1, the collector of the fourth switch Q4 is connected to the emitter of the third switch Q3, and the emitter of the fifth switch Q5 is connected to the sixth switch Q6. collector is connected.

Each of these switches Q1-Q6 is composed of a conventionally known insulated gate bipolar transistor (IGBT), and flywheel diodes D1-D6 are connected in anti-parallel to the IGBT, respectively. The first positive bus line 6 and the first negative bus line 7 are connected by a first capacitor 10 . The switches Q1 to Q6 are not limited to IGBTs, and may be MOSFETs.

One end of the U-phase coil 3u is connected to the connection point (connection portion) between the first switch Q1 and the second switch Q2, and the V-phase coil 3u is connected to the connection point (connection portion) between the third switch Q3 and the fourth switch Q4. One end of the coil 3v is connected, and one end of the W-phase coil 3w is connected to a connection point (connection portion) between the fifth switch Q5 and the sixth switch Q6.

A second inverter 5 is connected to the other ends of the U-phase coil 3u, the V-phase coil 3v, and the W-phase coil 3w. The second inverter 5 is composed of a second upper arm switch (element) 11 and a second lower arm switch (element) 12 as in the case of the first inverter 4 .

That is, the second upper arm switch 11 is composed of a seventh switch Q7, a ninth switch Q9 and an eleventh switch Q11, and the collectors of these switches Q7, Q9 and Q11 are connected to the second positive electrode bus 13. . The second lower arm switch 12 includes an eighth switch Q8 and a tenth switch Q8 whose collectors are connected to the emitters of the second upper arm switch 11 and whose emitters are connected to the second negative bus line 14, respectively. It is composed of a switch Q10 and a twelfth switch Q12. That is, the collector of the eighth switch Q8 and the other end of the U-phase coil 3u are connected to the emitter of the seventh switch Q7, and the collector of the tenth switch Q10 and the other end of the V-phase coil 3v are connected to the emitter of the ninth switch Q9. , and the collector of the twelfth switch Q12 and the other end of the W-phase coil 3w are connected to the emitter of the eleventh switch Q11.

Each of these switches Q7-Q12 is also composed of a conventionally known insulated gate bipolar transistor (IGBT), and flywheel diodes D7-D12 are connected in anti-parallel to the IGBT, respectively. The second positive electrode bus 13 and the second negative electrode bus 14 are connected by a first capacitor 15, the first negative electrode bus 7 and the second negative electrode bus 14 are connected in series, and the first positive electrode bus 13 and the second negative electrode bus 14 are connected in series. 6 and the second positive electrode bus 13 are connected via a switch 16 . This switch 16 is a normally open relay. The switches Q7 to Q12 are not limited to IGBTs and may be MOSFETs, and the switch 16 may be composed of semiconductor elements.

A positive electrode terminal 17 is formed on the second positive electrode bus 13 and a negative electrode terminal 18 is formed on the second negative electrode bus 14 . These positive terminal 17 and negative terminal 18 form a charging port 20 to which a charging facility (hereinafter referred to as a charging power supply) 19 such as an external power supply is connected. Note that when a connector (not shown) of the charging power source 19 is connected to a socket (not shown) between the second positive bus 13 and the positive terminal 17 and between the second negative bus 14 and the negative terminal 18, Open/close switches 21a and 21b are provided to connect the second positive bus line 13 and the positive terminal 17 and connect the second negative bus line 14 and the negative terminal 18, respectively.

Various sensors such as a detector 22 for detecting the voltage and current applied to the coils 3u, 3v, and 3w and an SOC management device 23 for detecting the remaining charge of the storage battery 2 are provided. there is

A control unit (controller) 24 for controlling the first inverter 4, the second inverter 5, and the switch 16 described above is provided. The control unit 24 controls the first inverter 4 (specifically, the first to sixth switches Q1 to Q6), the 2 A computing unit 25 that determines gate signals for controlling the inverter 5 (specifically, the seventh to twelfth switches Q7 to Q12) and determines whether the switch 16 is to be in the connected state or the cutoff state; It is composed of a first output section 26 that outputs a signal determined by the computing section 25 to the first inverter 4, a second output section 27 that outputs a signal determined by the computing section 25 to the second inverter 5, and the like. Note that the control unit 24 can be configured by, for example, software stored in a memory device, a computer that executes the software, hardware, or the like.

The power converter 1 configured as described above can control the output torque of the motor 3 by controlling the switch signals of the first inverter 4 and the second inverter 5 . In addition, the driving method can be changed by changing the open/closed state of the switch 16 according to the drive request. Here, in these drive states, the open/close switches 21a and 21b are opened because the charging power source 19 is not connected.

Further, when the charging power source 19 is connected and the open/close switches 21a and 21b are switched on, the switch 16, the first inverter 4 or the second By controlling the switch signal of the inverter 5 , the voltage of the charging power source 19 is stepped up or stepped down to charge the storage battery 2 .

A flow chart for explaining an example of the control is shown in FIG. The control example shown in FIG. 2 is executed when the charging power source 19 is connected to the charging port 20 . When the charging power supply 19 is connected to the charging port 20, the switch 16 is first opened (step S1). This step S1 is executed by, for example, outputting a signal for opening the switch 16 when an ON signal is input to the controller 24 from the open/close switches 21a and 21b.

Next, it is determined whether or not the voltage of the storage battery 2 is higher than the voltage of the charging power supply 19 (step S2). In this step S2, for example, the potential difference between the first positive electrode bus 6 and the first negative electrode bus 7 and the potential difference between the second positive electrode bus 13 and the second negative electrode bus 14 are measured, and the determination is made by comparing the potential differences. can do.

When the voltage of the storage battery 2 is higher than the voltage of the charging power supply 19 and the result of step S2 is affirmative, the second upper arm switch 11 is turned on (step S3). That is, the on-duties of the seventh switch Q7, the ninth switch Q9, and the eleventh switch Q11 are set to 100%. Note that the second lower arm switch 12 is brought into a non-conducting state.

A simplified equivalent circuit diagram for explaining the circuit state when the switch 16 is in the open state, the second upper arm switch 11 is in the conducting state, and the second lower arm switch 12 is in the non-conducting state as described above. are shown in FIG. Note that FIG. 3 shows only the U-phase coil 3u and the switches connected to the U-phase coil 3u.

As shown in FIG. 3, one end of the U-phase coil 3u is connected to the connection point between the first switch Q1 and the second switch Q2, and the other end of the U-phase coil 3u is connected to the positive electrode side of the charging power supply 19. . In addition, the negative electrode of the storage battery 2 and the emitter, which is the low potential side terminal of the second switch Q2, are connected to the negative electrode side of the charging power source 19 . Therefore, by using the U-phase coil 3u as a reactor to PWM (on/off) control the second switch Q2, the power converter 1 can function as a boost converter. Specifically, by setting the on-duty ratio of the second switch Q2 to 50%, the voltage of the charging power supply 19 can be doubled.

Therefore, following step S3, the first lower arm switch 9 is PWM-controlled (step S4). Therefore, the transmission of electric power between the storage battery 2 and the charging power source 19 is completed (step S5), and this routine is temporarily terminated. That is, the storage battery 2 is charged.

On the other hand, if the negative determination is made in step S2 because the voltage of the storage battery 2 is equal to or lower than the voltage of the charging power supply 19, it is determined whether or not the voltage of the storage battery 2 is less than the voltage of the charging power supply 19. (Step S6). This step S6 is determined by comparing the potential difference between the first positive electrode bus 6 and the first negative electrode bus 7 with the potential difference between the second positive electrode bus 13 and the second negative electrode bus 14, as in step S2 described above. can do.

When the voltage of the storage battery 2 is less than the voltage of the charging power source 19 and the result of step S6 is affirmative, the first upper arm switch 8 is turned on (step S7). That is, the on-duties of the first switch Q1, the third switch Q3, and the fifth switch Q5 are set to 100%. Note that the first lower arm switch 9 is brought into a non-conducting state.

A simplified equivalent circuit diagram for explaining the circuit state when the switch 16 is in the open state, the first upper arm switch 8 is in the conducting state, and the first lower arm switch 9 is in the non-conducting state as described above. is shown in FIG. Note that FIG. 4 shows only the U-phase coil 3u and the switches connected to the U-phase coil 3u.

As shown in FIG. 4, one end of the U-phase coil 3u is connected to the positive electrode side of the storage battery 2, and the other end of the U-phase coil 3u is connected to the connection point between the seventh switch Q7 and the eighth switch Q8. Also, the negative electrode of the storage battery 2 and the emitter, which is the low-potential terminal of the eighth switch Q8, are connected to the negative electrode side of the charging power source 19 . Therefore, by using the U-phase coil 3u as a reactor to PWM (on/off) control the seventh switch Q7, the power converter 1 can function as a step-down converter. Specifically, by setting the on-duty ratio of the seventh switch Q7 to 50%, the voltage of the charging power source 19 can be reduced by half.

Therefore, following step S7, the second upper arm switch 11 is PWM-controlled (step S8). Therefore, the transmission of electric power between the storage battery 2 and the charging power source 19 is completed (step S5), and this routine is temporarily terminated. That is, the storage battery 2 is charged.

On the other hand, when the voltage of the storage battery 2 is not less than the voltage of the charging power source 19 and thus the determination in step S6 is negative, the voltage of the storage battery 2 and the voltage of the charging power source 19 are the same. Therefore, if the determination in step S6 is negative, the storage battery 2 and the charging power source 19 are connected. Specifically, as shown in the simplified equivalent circuit diagram of FIG. 5, the first upper arm switch 8 and the second upper arm switch 11 are turned on (step S9). Since the first negative electrode bus 7 and the second negative electrode bus 14 are connected as described above, the charging power source 19 is directly connected to the negative electrode of the storage battery 2 . Therefore, in step S9, the first lower arm switch 9 and the second lower arm switch 12 are brought into a non-conducting state.

By bringing the first upper arm switch 8 and the second upper arm switch 11 into the conducting state in this way, the power transmission between the storage battery 2 and the charging power supply 19 is completed (step S5), and this routine is temporarily terminated. finish. That is, the storage battery 2 is charged.

When the voltage of the storage battery 2 and the voltage of the charging power supply 19 are the same, instead of making the first upper arm switch 8 and the second upper arm switch 11 conductive as in step S9, Alternatively, the switch 16 may be energized as shown in the simplified equivalent circuit diagram of FIG. In that case, the switches Q1 to Q12 of the first inverter 4 and the second inverter 5 are all turned off.

FIG. 7 shows the current value I _u flowing through the U-phase coil 3 u and the current value I ₈ is a time chart showing the voltage value VB detected at _BAT and the storage battery 2, and the voltage value _VBc of the charging power supply 19. As shown in FIG. there is

FIG. 8 shows the current value Iu flowing through the _U -phase coil 3u and the current flowing through the storage battery 2 when steps S7 and S8 are executed because the voltage of the charging power supply 19 is higher than the voltage of the storage battery 2. 9 is a time chart showing the value I _BAT , the voltage value V _B detected at the storage battery 2 portion, and the voltage value V _Bc of the charging power supply 19. As shown in FIG. It is

In addition to controlling the torque of the motor 3 by controlling the first switch Q1 to the twelfth switch Q12 as described above, it functions as a voltage regulator that increases or decreases the voltage of the charging power supply 19. can be done. In other words, there is no need to provide a voltage regulator or the like for changing the charging voltage in the power converter 1 for controlling the motor 3, and the electric unit can be miniaturized.

The power converter 1 according to the embodiment of the present invention is not limited to stepping up or stepping down the voltage of the charging power source 19 to charge the storage battery 2. may be configured to

1 power converter 2 storage battery 3 motor 3u, 3v, 3w coil 4, 5 inverter 6, 13 positive electrode bus 7, 14 negative electrode bus 8, 11 upper arm switch 9, 12 lower arm switch 10, 15 capacitor 16 switch 17 positive terminal 18 Negative terminal 19 Charging power supply 20 Charging port 21a, 21b Open/close switch 22 Detector 23 Management device 24 Control unit 25 Calculation unit 26, 27 Output unit D1 to D12 Flyhole diode Q1 to Q12 Switch

Claims (5)

a power supply;
a first inverter having a first upper arm element connected to the positive electrode side of the power supply, the first upper arm element, and a first lower arm element connected to the negative electrode side of the power supply;
a rotating machine having a coil having one end connected to a connecting portion between the first upper arm element and the first lower arm element in the first inverter;
A second upper arm element provided on the high potential side, the high potential side is connected to the low potential side of the second upper arm element, and the low potential side is connected to the negative electrode of the power supply and the low potential side of the first lower arm element. a second inverter having a connected second lower arm element and having the other end of the coil connected to a connecting portion between the second upper arm element and the second lower arm element; in
a switch capable of selectively connecting and disconnecting the positive electrode of the power supply and the high potential side of the first upper arm element and the high potential side of the second upper arm element;
A power converter, further comprising charging ports provided on a positive electrode side and a negative electrode side of the second inverter. In the power converter according to claim 1,
Further comprising a controller that controls the switch, the first inverter, and the second inverter,
The controller is
When a charging power source is connected to the charging port and the voltage of the power source and the voltage of the charging power source are the same, the switch is opened and the first upper arm element and the second 2. A power converter, characterized in that it is configured to enable power transmission between the power supply and the charging power supply by bringing an upper arm element into a conducting state. In the power converter according to claim 1,
Further comprising a controller that controls the switch, the first inverter, and the second inverter,
The controller is
When a charging power source is connected to the charging port and the voltage of the power source and the voltage of the charging power source are the same, the power source and the charging power source are connected by making the switch conductive. A power converter, characterized in that it is configured to allow power transfer between. In the power converter according to claim 1,
Further comprising a controller that controls the switch, the first inverter, and the second inverter,
The controller is
when a charging power source is connected to the charging port and the voltage of the power source is higher than the voltage of the charging power source, the switch is opened and the second upper arm element is conductive; and a power conversion device configured to enable power transmission between the power source and the charging power source by turning on and off the first lower arm element. In the power converter according to claim 1,
Further comprising a controller that controls the switch, the first inverter, and the second inverter,
The controller is
when a charging power source is connected to the charging port and the voltage of the power source is lower than the voltage of the charging power source, the switch is opened and the first upper arm element is conductive; and a power conversion device configured to enable power transmission between the power source and the charging power source by turning on and off the second lower arm element.

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