WO2022201466A1

WO2022201466A1 - Power supply device

Info

Publication number: WO2022201466A1
Application number: PCT/JP2021/012691
Authority: WO
Inventors: 由幸小林
Original assignee: 本田技研工業株式会社
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2022-09-29
Also published as: TWI818409B; JPWO2022201466A1; TW202239102A

Abstract

The present invention is a power supply device that includes high-potential side and low-potential side wiring to which a plurality of batteries are connected in parallel, a plurality of switching means for individually switching disconnection/connection of the plurality of batteries to the wiring, and a control means for controlling the plurality of switching means. The control means executes connection switching control in which one battery among the plurality of batteries that is connected to the wiring is sequentially switched.

Description

power supply

The present invention relates to power supply devices.

A power supply device that allows multiple battery packs to be connected in parallel has been proposed. On the other hand, if a plurality of battery packs with large voltage differences are connected in parallel, unintended phenomena such as current flow between the battery packs may occur. Patent Literature 1 discloses a device that uses the power of any one battery pack when the voltage difference between the two battery packs is large.

Chinese Patent No. 110682828A

In the device of Patent Literature 1, the power consumption of a specific battery pack increases, causing its deterioration, or the frequency of charging and replacement may increase.

An object of the present invention is to provide a power supply device that efficiently uses a plurality of batteries.

According to the invention,
high-potential-side and low-potential-side wiring to which a plurality of batteries are connected in parallel;
a plurality of switching means for individually switching the connection and disconnection of the plurality of batteries with respect to the wiring;
a control means for controlling the plurality of switching means;
A power supply device comprising:
The control means is
executing connection switching control for sequentially switching one of the plurality of batteries connected to the wiring within a unit time;
There is provided a power supply device characterized by:

According to the present invention, it is possible to provide a power supply device that efficiently uses a plurality of batteries with easy control.

1 is a block diagram of a power supply device according to an embodiment of the present invention; FIG. 4 is a timing chart showing the relationship between the ON/OFF timing of each switching element and the output voltage; 4 is a timing chart showing the relationship between the ON/OFF timing of each switching element and the output voltage; FIG. 10 is a diagram showing the ratio of connection time and changes in power ratio, output voltage, individual output power, and total output power; 4 is a flowchart showing an example of processing executed by a control circuit; 4 is a flowchart showing an example of processing executed by a control circuit; FIG. 2 is a block diagram showing a modification of the power supply device of FIG. 1; FIG. 4 is a block diagram showing another example of a power supply device with a different number of batteries; FIG. 9 is a timing chart showing ON/OFF timing of each switching element in the example of FIG. 8;

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined arbitrarily. Also, the same or similar configurations are denoted by the same reference numerals, and redundant explanations are omitted.

FIG. 1 is a block diagram of a power supply device 1 according to one embodiment of the present invention. The power supply device 1 is a device that uses a plurality of

batteries

2A and 2B (collectively referred to or referred to as batteries 2 when not distinguished) as power sources, which are DC power sources, and supplies power to a load. In the case of this embodiment, the load is the motor 3, and the power supply device 1 also functions as a driving device for driving the motor 3, and can be used as a driving device for driving the motor of a vehicle, for example. However, the present invention can be applied to power supply devices that supply power to various loads, and can also be applied to stationary power supplies, portable power supplies, and the like.

In the case of this embodiment, each battery 2 is a detachable battery, particularly a mobile battery pack detachable from the power supply device 1 . However, each battery 2 may be fixedly provided with the power supply device 1, and some of the batteries may be mobile battery packs, and the remaining batteries may be batteries fixedly provided in the power supply device 1. good too.

Each battery 2 includes a power storage unit 2a and a BMU (management system) 2b that manages the power storage unit 2a. The power storage unit 2a stores electric power output from the battery 2, and is configured by, for example, connecting a plurality of battery cells in series. The battery cells are, for example, lithium-ion battery cells.

The BMU 2b communicates with a processor that controls charging and discharging of the power storage unit 2a, a storage device such as a semiconductor memory that stores programs executed by the processor and information about the state of the power storage unit 2a, an input/output interface, and a control circuit 19, which will be described later. Includes a communication interface that performs The BMU 2b also includes a detection circuit that detects the remaining amount, charging/discharging current, and charging/discharging voltage of the power storage unit 2a, and the processor controls the upper limit of the discharge power of the battery 2 and the charging amount based on the detection result of the detection circuit. do. For example, when the discharged power of the battery 2 reaches the upper limit, the processor controls discharging of the power storage unit 2a so as to maintain the discharged power of the battery 2 at the upper limit.

In this embodiment, the motor 3 is an AC motor, such as a three-phase brushless motor. A power supply device 1 converts a DC voltage output from a battery 2 into an AC voltage to drive a motor 3 .

The power supply device 1 includes

terminals

10a, 10b, and 10c to which the battery 2A is electrically connected, and

terminals

11a, 11b, and 11c to which the battery 2B is electrically connected. A positive terminal of the battery 2 is connected to the

terminals

10a and 11a, and a negative terminal of the battery 2 is connected to the

terminals

10b and 11b. Communication terminals of the BMU 2b of the battery 2 are connected to the

terminals

10c and 11c.

The power supply device 1 includes a DC wiring 12 on the high potential side and a DC wiring 13 on the low potential side. A potential difference (voltage) between the DC wiring 12 and the DC wiring 13 is called an output voltage Vout. The power supply device 1 also includes a plurality of switching elements SW1 and SW2. The DC wiring 12 is connected to the terminal 10a through the switching element SW1, and is also connected to the terminal 11a through the switching element SW2. DC wiring 13 is connected to

terminals

10b and 11b. With such a configuration, a plurality of

batteries

2A and 2B are connected in parallel to

DC wirings

12 and 13. FIG.

The switching elements SW1 and SW2 are, for example, transistors, and individually switch the connecting/disconnecting of the plurality of

batteries

2A and 2B to the

DC wirings

12 and 13 according to the control signal from the control circuit 19 . In this embodiment, the switching element SW1 connects the positive terminal of the battery 2A and the DC wiring 12 when turned on, and disconnects the positive terminal of the battery 2A and the DC wiring 12 when turned off. Switching element SW2 connects the positive terminal of battery 2B and DC wiring 12 when turned ON, and disconnects the positive terminal of battery 2B and DC wiring 12 when turned OFF.

A diode 15 is provided between the DC wiring 12 and the DC wiring 13 to regulate the flow of current from the DC wiring 13 to the DC wiring 12 . The power supply device 1 also includes a smoothing circuit 14 that smoothes the output voltage Vout of the

DC wirings

12 and 13 . In this embodiment, the smoothing circuit 14 is an LC filter circuit including an inductor 14 a connected in series with the DC wiring 12 and a capacitor 14 b connected between the DC wiring 12 and the DC wiring 13 .

The power supply device 1 includes an inverter 17. An output voltage Vout is input to the inverter 17 , and the inverter 17 converts the output voltage Vout, which is a DC voltage, into an AC voltage and outputs the AC voltage from a three-phase terminal 18 to the motor 3 . The inverter 17 includes, for example, an H-bridge circuit having four FETs (Field Effect Transistors) and a control circuit that sequentially switches the FETs on and off, and converts the output voltage Vout into a single-phase AC voltage. A voltage detection circuit 16 detects an output voltage Vout input to the inverter 17 .

The power supply device 1 includes a control circuit 19 . The control circuit 19 includes, for example, a processor, a storage device such as a semiconductor memory, an input/output interface, a communication interface, and the like. The storage device stores programs executed by the processor, data used for processing by the processor, and the like.

The control circuit 19 is communicably connected to the BMU 2b of each battery 2 via

terminals

10c and 11c, and can acquire output capability information from the BMU 2b. The output capability information is state information related to the power that the battery 2 can currently output, such as remaining amount information (SOC: remaining capacity/fully charged capacity×100), voltage information (each output voltage V1, V2), etc. information.

The control circuit 19 is also communicably connected to the control circuit of the inverter 17 . The control circuit 19 is also connected to the voltage detection circuit 16 and can acquire the detection result from the voltage detection circuit 16 .

<Battery connection control>
The control circuit 19 switches the connection mode of the

batteries

2A and 2B to the DC wirings 12 and 13 by controlling the ON/OFF of the switching elements SW1 and SW2. In the mode in which both the

batteries

2A and 2B are connected to the DC wirings 12 and 13, the power that can be supplied to the inverter 17 is maximized. However, if the difference between the output voltages of

batteries

2A and 2B is large, current can flow from one battery to the other. In this embodiment, since the

batteries

2A and 2B are replaceable mobile battery packs, the difference between the output voltages of the

batteries

2A and 2B is likely to be large. In such a case, it is conceivable to continuously connect only one of the batteries to the

DC wiring

12 and 13, but the power consumption of that battery increases, causing its deterioration, or the frequency of charging and replacement increases. may become.

In this embodiment, the control circuit 19 executes connection switching control to alternately connect the

batteries

2A and 2B to the DC wirings 12 and 13, thereby efficiently using the plurality of

batteries

2A and 2B. FIG. 2 is an explanatory diagram thereof. In FIG. 2, t indicates the passage of time, and T indicates unit time. In the connection switching control, the unit time T is set as one cycle, and within the unit time T, one of the

batteries

2A and 2B connected to the DC wirings 12 and 13 is sequentially switched repeatedly. The unit time T is, for example, a time within the range of 50 μs to 1 ms. V1 indicates the output voltage of battery 2A, and V2 indicates the output voltage of battery 2B. In the illustrated example, there is a relationship of V1>V2.

The output voltage Vout is the output voltage V1 when the switching element SW1 is on and the switching element SW2 is off, and the output voltage Vout is the output voltage V2 when the switching element SW2 is on and the switching element SW1 is off. The output voltage Vout becomes the voltage V when averaged over the unit time T. FIG.

In the example of FIG. 2, within the unit time T, the ON time of the switching element SW1 (connection time of the battery 2A) and the ON time of the switching element SW2 (connection time of the battery 2B) are both T/2. . When the ratio of ON/OFF time in the unit time T is expressed as a duty ratio, the duty ratio of the switching element SW1 is 50%, and the duty ratio of the switching element SW2 is 50%. The average voltage V of the output voltage Vout is V=1/2×(V1+V2). The temporal waveform of the output voltage Vout is a signal that alternately repeats V1 and V2. Even if the difference between V1 and V2 is large, the output voltage Vout is smoothed by the smoothing circuit 14 and input to the inverter 17 because the smoothing circuit 14 is provided in this embodiment.

Assuming that V1=60V, V2=40V, and the current consumption is 100A, the output voltage to the inverter 17 is V=50V, and the output power W=5kw. In this case, the average power drawn from battery 2A is 3 kw and the average power drawn from battery 2B is 2 kw.

The control circuit 19 can change the connection time of each

battery

2A and 2B to the DC wirings 12 and 13, that is, the duty ratio. FIG. 3 shows an example in which the duty ratio is changed. In the illustrated example, the duty ratio of the switching element SW1 is 20%, and the duty ratio of the switching element SW2 is 80%. The average voltage V of the output voltage Vout is V=1/5*V1+4/5*V2.

FIG. 4 shows the relationship between the duty ratio of the switching element SW1 and the power ratio between the battery 2A and the battery 2B (graph G1), the relationship with the output voltage (graph G2), and the output of the battery 2A when V1>V2. The relationship with the possible power W1-max (graph G3), the relationship with the possible output power W2-max of the battery 2B (graph G4), and the relationship with the possible output power to the inverter 17 (graph G5) are shown.

Since the duty ratio in FIG. 4 represents the duty ratio of the switching element SW1, when the duty ratio is 0%, the duty ratio of the switching element SW2 is 100%. Conversely, when the duty ratio is 100%, the duty ratio of the switching element SW2 is 0%. The horizontal axes of the graphs G1 to G5 all represent the duty ratio of the switching element SW1.

In the graph G1, assuming that the current consumption is the same regardless of which of the

batteries

2A and 2B is connected to the

DC wiring

12 and 13, the ratio of the power drawn from the battery 2A and the battery 2B is 50% because the graph When the duty ratio is less than 50% as indicated by G1.

In the graph G2, when the duty ratio is 0%, the output voltage (Vout) is the output voltage V2 of the battery 2B, and when the duty ratio is 100%, the output voltage (Vout) is the output voltage V1 of the battery 2A ( G2). The output voltage changes depending on the duty ratio.

A graph G3 shows the output power W1-max of only the battery 2A in a unit time T. Possible output power W1-max increases as the duty ratio increases from 0%. At a duty ratio where the power ratio is 50%, the discharge power of the battery 2A reaches the upper limit (for example, the discharge current upper limit), and the output is regulated by the BMU 2b of the battery 2A. The available power W1-max does not increase.

A graph G4 shows the possible output power W2-max of only the battery 2B in a unit time T. As the duty ratio decreases from 100%, the duty ratio of the switching element SW2 increases from 0%, so the output power W2-max increases. At the duty ratio at which the power ratio is 50%, the discharge power of the battery 2B reaches the upper limit (for example, the discharge current upper limit), the output is regulated by the BMU 2b of the battery 2B, and then the duty ratio decreases (switching element SW2 (the duty ratio of ) does not increase the outputtable power W2-max.

A graph G5 shows the power W-max that can be output to the inverter 17 in a unit time T, which is the sum of the powers W1-max and W2-max that can be output from the

batteries

2A and 2B. The outputtable power W-max is maximized at the duty ratio at which the power ratio is 50%, and the outputtable power W-max decreases regardless of whether the duty ratio is increased or decreased. By controlling the duty ratio, it is possible to control the output voltage Vout and the output power W-max while protecting the battery 2 by regulating the discharge power of the battery 2 by the BMU 2b.

<Processing example>
An example of processing executed by the processor of the control circuit 19 will be described. FIG. 5 is a flow chart showing an example of processing for selecting control modes of the switching elements SW1 and SW2. The processor of the control circuit 19 periodically executes the processing shown in FIG. In S1, the voltage information of the

batteries

2A and 2B (the output voltages V1 and V2) of the

batteries

2A and 2B is obtained by communication from the BMUs 2b of the

batteries

2A and 2B. In S2, the voltage difference between the output voltages (V1, V2) obtained in S1 is calculated. In S3, it is determined whether or not the voltage difference (=|V1-V2|) calculated in S2 exceeds a threshold. The threshold is, for example, a value within the range of 1.5V, or a value between 1% and 3% of the average value of each output voltage (V1, V2).

If the voltage difference calculated in S2 exceeds the threshold, proceed to S4, otherwise proceed to S5. In S4, the connection switching control described above is executed, and the

batteries

2A and 2B are alternately connected to the DC wirings 12 and 13. FIG. Simultaneous connection control is executed in S5 to connect the

batteries

2A and 2B to the DC wirings 12 and 13 together.

In the simultaneous connection control of S5, both the switching elements SW1 and SW2 are controlled to be ON. Larger power can be supplied to the motor 3, which is the load, than in connection switching control. In the connection switching control of S4, it is possible to efficiently use these batteries 2 while preventing current from flowing between the

batteries

2A and 2B.

FIG. 6 is a flowchart showing an example of drive control of the switching elements SW1 and SW2 that is executed when the connection switching control of S4 is selected, and is periodically executed at a shorter cycle than the process of FIG. In S<b>11 , the detection result of the output voltage Vout is acquired from the voltage detection circuit 16 . In S12, the difference between the output voltage Vout obtained in S11 and the target output voltage is calculated. In S13, the voltage information of the

batteries

2A and 2B (the output voltages V1 and V2) of the

batteries

2A and 2B is obtained by communication from the BMUs 2b of the

batteries

2A and 2B. In S14, based on the difference calculated in S12 and the voltage information obtained in S13, the duty ratios of the switching elements SW1 and SW2 are set so that the difference calculated in S12 becomes small. The duty ratio is set within the range of 0%<duty ratio<100%. At S15, switching of the switching elements SW1 and SW2 is executed at the duty ratio set at S14. Through the above processing, the output voltage Vout can be maintained at the target output voltage.

<Other embodiments>
In the above embodiment, the switching elements SW1 and SW2 are provided in the DC wiring 12 on the high potential side, but they may be provided in the DC wiring 13 on the low potential side. FIG. 7 shows an example thereof. In the illustrated example, both the switching elements SW1 and SW2 are provided in the DC wiring 13 . A configuration in which some of the switching elements are provided in the DC wiring 12 and the remaining switching elements are provided in the DC wiring 13 can also be adopted.

Next, in the above embodiment, the control mode of the switching elements SW1 and SW2 is selected based on the voltage information acquired from the BMU 2b (S1 to S3), but the control mode is selected based on the output capability information other than the voltage information. You may For example, connection switching control may be executed when the difference in SOC between the

batteries

2A and 2B exceeds a predetermined value, and simultaneous connection control may be executed when the difference is equal to or less than the predetermined value.

Next, although two batteries 2 are used in the above embodiment, three or more batteries 2 may be used. FIG. 8 is a block diagram showing a power supply device 1A to which four batteries 2A-2D can be connected. The configuration of the power supply device 1A is the same as the configuration of FIG. can be switched to FIG. 9 is an explanatory diagram of connection switching control in the configuration example of FIG. In the illustrated example, each duty ratio of the switching elements SW1 to SW4 is 25%.

Next, the power supply device 1 in FIG. 1 includes the inverter 17 and is configured to output AC power. However, the configuration may be such that the output voltage Vout is directly supplied to an external load without including the inverter 17 .

Next, in the process of FIG. 5, an example of selecting simultaneous connection control when the voltage difference is equal to or less than the threshold in S3 has been described (S5). In addition to this, other conditions may also be included. Another condition is, for example, the case where the required power of the load exceeds a predetermined threshold. If other conditions are not satisfied, connection switching control may be selected even if the voltage difference is equal to or less than the threshold.

<Summary of embodiment>
The above embodiments disclose at least the following power supply devices.

1. The power supply device (1, 1A) of the above embodiment includes:
High potential side and low potential side wiring (12, 13) to which a plurality of batteries (2) are connected in parallel;
a plurality of switching means (SW) for individually switching the connection and disconnection of the plurality of batteries with respect to the wiring;
a control means (19) for controlling the plurality of switching means;
A power supply device comprising:
The control means is
Connection switching control is executed to sequentially switch one of the plurality of batteries connected to the wiring within a unit time (S4).
According to this embodiment, it is possible to provide a power supply device that efficiently uses a plurality of batteries with easy control.

2. In the above embodiment,
In the connection switching control, the connection time of each battery to the wiring within the unit time can be changed (S14).
According to this embodiment, the DC output voltage can be controlled.

3. The power supply device of the above embodiment includes:
A detection means (16) for detecting the output voltage of the wiring,
The control means is
In the connection switching control, the connection time of each battery to the wiring within the unit time is changed based on the detection result of the detection means (S11, S14).
According to this embodiment, the DC output voltage can be controlled according to the target voltage.

4. In the above embodiment,
The control means determines whether or not to execute the connection switching control based on the output capability information of each of the plurality of batteries (S3).
According to this embodiment, when there is a difference in output capability between the batteries, the connection switching control is executed to utilize the batteries.

5. In the above embodiment,
The control means executes the connection switching control when the output voltage difference between the plurality of batteries exceeds a predetermined value (S3, S4).
According to this embodiment, when there is a possibility that a current may flow between the batteries, the connection switching control is executed to prevent such a situation and utilize the batteries.

6. In the above embodiment,
The control means executes control to simultaneously connect the plurality of batteries to the wiring on condition that the output voltage difference between the plurality of batteries is equal to or less than a predetermined value (S3, S5).
This embodiment allows more power to be supplied to the load.

7. The power supply device of the above embodiment includes:
A smoothing circuit (S14) is provided for smoothing the output voltage of the wiring.
According to this embodiment, even if one battery connected to the wiring is sequentially switched, an averaged and stable voltage can be output.

8. In the above embodiment,
each of the plurality of batteries is a mobile battery pack equipped with a management system (2b);
The control means is communicable with the management system.
According to this embodiment, information about the state of the mobile battery pack can be obtained from the management system.

9. In the above embodiment,
The management system controls the upper limit of the discharge power of the battery.
According to this embodiment, a plurality of batteries can be efficiently used while protecting the batteries.

10. The power supply device of the above embodiment includes:
An inverter (17) is provided for converting the output voltage (Vout) of the wiring into an AC voltage.
According to this embodiment, power can be supplied to a load that consumes AC power.

11. In the above embodiment,
At least one of the plurality of batteries is a removable battery.
According to this embodiment, detachable batteries with different usage states and deterioration states can be effectively used.

Although the embodiments of the invention have been described above, the invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention.

Claims

high-potential-side and low-potential-side wiring to which a plurality of batteries are connected in parallel;
a plurality of switching means for individually switching the connection and disconnection of the plurality of batteries with respect to the wiring;
a control means for controlling the plurality of switching means;
A power supply device comprising:
The control means is
executing connection switching control for sequentially switching one of the plurality of batteries connected to the wiring within a unit time;
A power supply device characterized by:
The power supply device according to claim 1,
In the connection switching control, the connection time of each battery to the wiring within the unit time can be changed.
A power supply device characterized by:
The power supply device according to claim 1,
A detection means for detecting the output voltage of the wiring,
The control means is
In the connection switching control, changing the connection time of each battery to the wiring within the unit time based on the detection result of the detection means;
A power supply device characterized by:
The power supply device according to any one of claims 1 to 3,
The control means determines whether or not to execute the connection switching control based on the output capacity information of each of the plurality of batteries.
A power supply device characterized by:
The power supply device according to any one of claims 1 to 3,
The control means executes the connection switching control when an output voltage difference between the plurality of batteries exceeds a predetermined value.
A power supply device characterized by:
The power supply device according to any one of claims 1 to 3,
The control means performs control to simultaneously connect the plurality of batteries to the wiring on condition that an output voltage difference between the plurality of batteries is equal to or less than a predetermined value.
A power supply device characterized by:
The power supply device according to any one of claims 1 to 6,
A smoothing circuit for smoothing the output voltage of the wiring,
A power supply device characterized by:
The power supply device according to any one of claims 1 to 7,
each of the plurality of batteries is a mobile battery pack equipped with a management system;
the control means is communicable with the management system;
A power supply device characterized by:
The power supply device according to claim 8,
The management system controls an upper limit of discharge power of the battery.
A power supply device characterized by:
The power supply device according to any one of claims 1 to 9,
An inverter that converts the output voltage of the wiring into an alternating voltage,
A power supply device characterized by:
The power supply device according to claim 1,
At least one of the plurality of batteries is a removable battery,
A power supply device characterized by: