WO2023159704A1

WO2023159704A1 - Battery series-parallel connection switching main circuit without power output interruption, and system and method

Info

Publication number: WO2023159704A1
Application number: PCT/CN2022/081877
Authority: WO
Inventors: 贺洪芝
Original assignee: 贺洪芝
Priority date: 2022-02-22
Filing date: 2022-03-21
Publication date: 2023-08-31
Also published as: CN114506225B; CN114506225A

Abstract

The present invention relates to the field of circuit apparatuses used for power supply to battery packs, and provides a battery series-parallel connection switching main circuit without a power output interruption, and a system and a method. When two battery modules output power to an electric drive system that comprises an electric motor controller and an electric motor, the main circuit and the method can perform series-parallel connection switching without power interruption, thereby solving the problem of power interruption during switching by means of a switching circuit which mainly uses three relays. The main circuit comprises a first battery positive electrode port, a first battery negative electrode port, a second battery positive electrode port, a second battery negative electrode port, a first switch electrically coupled between the first battery positive electrode port and the second battery positive electrode port, a second switch electrically coupled between the second battery negative electrode port and the first battery negative electrode port, a diode electrically coupled between the first battery positive electrode port and the second battery negative electrode port, and a semiconductor contactless switch electrically coupled between the first battery negative electrode port and the second battery positive electrode port.

Description

Battery series-parallel switching main circuit, system and method without power output interruption

technical field

The invention relates to a circuit device for battery pack power supply, in particular to a circuit and method for battery series-parallel switching without interruption of power output, and a battery pack, an electric propulsion system and a vehicle using the circuit or method.

Background technique

In order to realize the fast charging function, electric vehicles need greater charging power, but the greater charging power is limited by the maximum charging current of the 400V voltage platform and cannot meet the needs of fast charging time, so electric vehicles with 800V voltage platform came into being. and meet the needs of fast charging. However, due to the lag in the construction of 800V fast charging basic charging facilities, the coverage network cannot meet the demand. Therefore, electric vehicles with 800V voltage platform need charging piles with 400V voltage platform to be able to charge them when there is no fast charging pile with 800V voltage platform. Therefore, an electric vehicle equipped with two 400V voltage platform battery modules can be flexibly configured as a 400V or 800V voltage platform by connecting the two battery modules in series and parallel to meet the needs of 800V fast charging and the above-mentioned 400V voltage platform charging pile charging. The 400V voltage platform charging pile for the battery with a fixed battery voltage output on the 800V voltage platform also needs a 400V to 800V step-up DC converter on board, while the above-mentioned two battery module series-parallel connection scheme does not need the step-up DC converter. Therefore, the series-parallel connection scheme of battery modules has a relatively large cost competitive advantage.

The main load of the electric vehicle battery pack is the electric drive system including the motor controller and the motor. In order to reduce the loss of the electric drive system, an ideal battery power supply method is to use different batteries when the motor works in different speed ranges. voltage output. Generally, a lower battery voltage is required when the motor operates in a low-speed area, and a higher battery voltage is required when operating in a high-speed area. Therefore, an electric vehicle with an 800V voltage platform realized by using two 400V voltage platform battery modules through series-parallel switching is available. The output voltage of the battery pack needs to change during driving. In the low-speed area, the two battery modules are connected in parallel to output a 400V voltage platform voltage. When accelerating to the high-speed area, the two battery modules switch the two battery modules into a Connect in series to output 800V voltage platform voltage.

technical problem

The technical solution of the existing series-parallel switching circuit is to use three relays as series-parallel switching switches to switch the main circuit, and the main purpose is to solve the problem of charging the 800V voltage platform battery by the charging pile of the 400V voltage platform. A case where a parallel switching circuit is applied when driving a car. To meet the requirements of this application, it is necessary to solve the problem that the series-parallel switching operation of the two battery modules cannot interrupt the power output from the battery pack to the electric drive system when driving. The existing three-relay main circuit technical scheme has the following problems. 1. In the process of switching from the parallel connection state to the series connection, when the switch supporting the parallel connection is disconnected, the self-inductance current on the positive and negative pole lines of the power supply between the battery and the motor controller has no freewheeling circuit, resulting in the disconnection of each switch at the moment of disconnection. A high overshoot voltage is generated at both ends, which is likely to cause arc flashover and erosion between contacts or overvoltage breakdown of semiconductor non-contact switches; 2. It takes a long time for the relay to receive the closing instruction signal to contact closing. After the switch that supports parallel connection is disconnected, it takes a long time for the switch that supports series connection to complete the contact closure. If the electric vehicle is in the acceleration condition from low speed to highest speed at this time, it corresponds to the motor from low speed to high speed. In the load acceleration phase of the load acceleration stage, the power output of the battery pack is interrupted during the period after the switch that supports parallel connection is turned off and before the switch that supports series connection is closed. During this period, the voltage of the DC bus support capacitor of the motor controller drops rapidly. It will cause no power output to the motor controller, and then the power of the electric drive system or the vehicle will be interrupted when accelerating, which will have a great negative impact on the vehicle's power performance and driving experience; 3. Existing The technical scheme of the three-relay main circuit cannot solve the problem of large current impact in the process of switching from parallel connection to series connection when the battery pack outputs drive power to the motor controller. When the switch supporting series connection is closed, since there is a huge voltage difference between the above-mentioned DC bus support capacitor voltage and the voltage of the series-connected battery pack, once the switch supporting series connection is forcibly closed, there will be a gap between the battery pack and the above-mentioned DC bus support capacitor. A large inrush current is generated in the circuit between them. When the switch that supports series connection is closed, it will cause local high heat in the contact area or even arc flashover and erosion on the two contact contacts of the relay, which greatly affects the reliability and reliability of contact contact. At the same time, excessive inrush current has an adverse effect on the above-mentioned DC bus support capacitors and batteries, and high current change rates or arcs will cause electromagnetic interference to peripheral circuits.

technical solution

In order to solve the above problems, the present invention proposes technical solutions from five aspects, including:

The technical solution of the first aspect proposes a circuit, the core of which is a main circuit for switching between series and parallel of two battery modules, and the circuit also includes a control circuit unit and a power supply circuit between the battery pack and the motor controller. The circuit is embodied in technical solutions 1 to 3 below.

Technical solution 1. A circuit, comprising:

The main circuit is used for series-parallel switching of two battery modules, the two battery modules include a first battery module and a second battery module, and each of the battery modules has a positive pole and a negative pole, The two battery modules can be configured to be connected in series or in parallel by the main circuit, and the positive and negative poles of the two battery modules connected in series or in parallel are connected through the main positive relay, the main negative relay, the fuse, and the positive power line. And the negative power supply line is electrically coupled to an electric drive system including a motor controller and a motor for energy transfer, and the main circuit includes:

a positive terminal of the first battery, which is electrically coupled to the positive terminal of the first battery module;

a first battery negative terminal electrically coupled to the negative terminal of the first battery module;

a second battery positive terminal electrically coupled to the positive terminal of the second battery module;

a second battery negative terminal electrically coupled to the negative terminal of the second battery module;

A first switch, which has a first terminal, a second terminal and at least one control terminal, the first terminal of the first switch and the second terminal of the first switch are electrically coupled to the positive port of the first battery Between the positive terminal of the second battery, the control terminal of the first switch can configure the first switch to be in a bidirectional current conducting state or a bidirectional current blocking state; and

A second switch, which has a first terminal, a second terminal and at least one control terminal, the first terminal of the second switch and the second terminal of the second switch are electrically coupled to the negative terminal of the second battery Between the negative terminal of the first battery, the control terminal of the second switch can configure the second switch to be in a bidirectional current conducting state or a bidirectional current blocking state;

Wherein, the main circuit also includes:

a diode, which is electrically coupled between the positive port of the first battery and the negative port of the second battery, the cathode of the diode is electrically coupled to the positive port of the first battery, and the anode of the diode is electrically coupled connected to the negative terminal of the second battery; and

A semiconductor non-contact switch, which has a first terminal, a second terminal and at least one control terminal, the first terminal of the semiconductor non-contact switch and the second terminal of the semiconductor non-contact switch are electrically coupled to the Between the negative terminal of the first battery and the positive terminal of the second battery, the semiconductor non-contact switch includes a transistor or a plurality of transistors connected in series or in parallel, and the control terminal of the semiconductor non-contact switch can be configured with the The semiconductor non-contact switch is in a bidirectional current conduction state or a bidirectional current blocking state.

Technical solution 2. The circuit according to technical solution 1, wherein, further comprising a control circuit unit, the functions realized by the control circuit unit include:

providing the drive output required by the main circuit;

Voltage sampling monitoring, which includes voltage sampling monitoring between the first battery positive port and the first battery negative port, voltage sampling monitoring between the second battery positive port and the second battery negative port, Sampling and monitoring the voltage between the positive terminal of the first battery and the negative terminal of the second battery;

current sampling monitoring, which includes current sampling monitoring between the positive port of the first battery or the negative port of the second battery and the motor controller,

Switch state sampling monitoring, which includes switching state sampling monitoring of the first switch, switching state sampling monitoring of the second switch, and switching state sampling monitoring of the semiconductor non-contact switch; and

receiving information including the actual current speed of the motor and a series-parallel switching instruction, and making configurations of the two battery modules based on the voltage values monitored by the voltage sampling and the switch states monitored by the switch state sampling For the selection of series or parallel connection, and output the corresponding driving output signal to the main circuit;

The control circuit unit includes:

drive output port 1, which is electrically coupled to the control end of the first switch;

drive output port 2, which is electrically coupled to the control end of the second switch;

drive output port 3, which is electrically coupled to the control terminal of the semiconductor non-contact switch;

a voltage sampling input port 1, which is electrically coupled to the positive port of the first battery and the negative port of the first battery;

a voltage sampling input port 2, which is electrically coupled to the positive port of the second battery and the negative port of the second battery;

The current sampling input port is electrically coupled to the output port of the current detection device, and the current detection device detects the current between the first battery positive port or the second battery negative port and the motor controller; as well as

A communication port, which receives information including the actual current speed of the motor and a series-parallel switching command through an external communication bus, and the process status of the series-parallel switching of the two battery modules and the result status of the switching completion are passed through the communication port. port output onto the communication bus.

Technical scheme 3. The circuit according to technical scheme 2, which further comprises:

a first battery module, which is the first battery module, The positive pole of the first battery module is electrically coupled to the positive terminal of the first battery, and the negative pole of the first battery module is electrically coupled to the negative terminal of the first battery;

a second battery module, which is the second battery module, The positive pole of the second battery module is electrically coupled to the positive port of the second battery, and the negative pole of the second battery module is electrically coupled to the negative port of the second battery;

a first inductance, which includes the self-inductance of the positive power supply line, and the first inductance is electrically coupled between the positive terminal of the first battery and the positive pole of the DC bus support capacitor of the motor controller;

a second inductance, which includes the self-inductance of the negative power supply line, the second inductance is electrically coupled between the negative terminal of the second battery and the negative pole of the DC bus support capacitor of the motor controller;

The fourth capacitor is the DC bus support capacitor of the motor controller. The motor controller inverts the DC power of the two battery modules into multi-phase AC power to drive the motor. The fourth capacitor The positive pole of the fourth capacitor is electrically coupled to the positive pole of the first battery module via the first inductor, and the negative pole of the fourth capacitor is electrically coupled to the negative pole of the second battery module via the second inductor. ;as well as

A first current detection device, the first current detection device detects the current between the positive terminal of the first battery or the negative terminal of the second battery and the motor controller.

The second technical solution proposes an electric propulsion system, including:

The circuit of the technical solution of the first aspect;

an electric motor configured to apply torque to its mechanical load;

A motor controller, which is connected to the motor, the positive pole of the DC bus support capacitor of the motor controller is electrically coupled to the positive terminal of the first battery, and the negative pole of the DC bus support capacitor of the motor controller is electrically coupled to to the negative terminal of the second battery;

A communication bus, the motor controller and the circuit of the technical solution of the first aspect are connected through the communication bus to perform information exchange.

The technical solution of the third aspect proposes a vehicle including the electric propulsion system described in the technical solution of the second aspect, the voltage of the supporting capacitor in the parallel state and the voltage of the supporting capacitor in the series state of the motor controller of the electric propulsion system are the first correlation configuration or the second associated configuration; the parallel state support capacitor voltage is the output current of the two battery modules in the parallel connection state via the closed main positive relay and the main negative relay, the fuse, The steady-state voltage value of the positive power supply line and the negative power supply line on the fourth capacitor; the series support capacitor voltage is the output current of the two battery modules in the series connection state through the closed The steady-state voltage values of the main positive relay and the main negative relay, the fuse, the positive power line and the negative power line on the fourth capacitor;

The first association configuration is that the parallel state support capacitor voltage of the motor controller is at least 250V to 450V, and the series state support capacitor voltage of the motor controller is at least 500V to 900V;

The second association configuration is that the parallel state support capacitor voltage of the motor controller is at least 125V to 225V, and the series state support capacitor voltage of the motor controller is at least 250V to 450V.

The technical solution of the fourth aspect proposes a method for operating the circuit described in the technical solution of the first aspect, and the functions realized by the method include passing the The method can realize that the positive mechanical power output of the motor is not interrupted when the two battery modules are switched in series and parallel, and the state of the positive mechanical power output of the motor is manifested by the fact that the current direction on the positive power supply line is from the first the battery positive terminal flows to the motor controller, the method comprising:

Operate the circuit to switch the two battery modules from parallel connection to series connection or from series connection to parallel connection. The drive system works in a non-energy feedback state. When the non-energy feedback state is the positive current direction of the positive power line or when the positive power line has zero current, the positive current direction of the positive power line is the direction of the two battery modules. The discharge current of the group flows from the positive terminal of the first battery to the motor controller, the zero current of the positive power supply line means that the current on the positive power supply line is zero, and the switching process is the start moment of the series-parallel switching of the circuit the time period until the end moment of the handover;

The sequence and method of switching the two battery modules from parallel connection to series connection:

Step 1, disconnecting the first switch and the second switch;

The second step is to confirm that the switching state sampling monitoring of the first switch and the second switch are both blocking states, and the switching state sampling monitoring of the semiconductor non-contact switch is blocking state;

The third step is to use the step-down pulse width modulation method to increase the voltage of the fourth capacitor to the supporting capacitor voltage in a series state. The step-down pulse width modulation method is to use the semiconductor non-contact switch, the diode, The step-down circuit composed of the first inductance, the second inductance and the fourth capacitor controls the semiconductor non-contact switch to work alternately in conduction and resistance through the control terminal of the semiconductor non-contact switch. off state, and gradually increase the on-pulse width duty ratio from zero until the fourth capacitor voltage is raised to the support capacitor voltage in the series state, and the support capacitor voltage in the series state is the voltage of the two battery modules in the The steady-state voltage value of the output current in the series connection state on the fourth capacitor through the closed main positive relay and the main negative relay, the fuse, the positive power supply line and the negative power supply line ;

The fourth step is to stop the alternate operation of conduction and blocking of the semiconductor non-contact switch and control the semiconductor non-contact switch to always work in the conduction state;

The sequence and method of switching the two battery modules from series connection to parallel connection include two subdivision methods when the positive power line is in the positive current direction and when the positive power line is in zero current:

When the positive power line is in the positive current direction, the order and method of switching the two battery modules from series connection to parallel connection:

In the first step, adopt step-down pulse width modulation method 2 to slow down the reduction speed of the fourth capacitor voltage, and gradually reduce the voltage of the fourth capacitor toward the parallel state to support the capacitor voltage, the step-down pulse width modulation method 2 is Utilize the step-down circuit composed of the semiconductor non-contact switch, the diode, the first inductance, the second inductance and the fourth capacitor, and then control the The semiconductor non-contact switch works alternately in the conduction and blocking states, and gradually reduces the conduction pulse width duty cycle from the maximum conduction pulse width duty cycle, thereby reducing the voltage of the fourth capacitor, and the parallel state The supporting capacitor voltage is the output current of the two battery modules connected in parallel through the closed main positive relay and the main negative relay, the fuse, the positive power line and the negative power line A steady-state voltage value on the fourth capacitor;

In the second step, when the voltage difference between the capacitor and the battery reaches a preset range, the semiconductor non-contact switch is controlled to be in a constant blocking state, and the voltage difference between the capacitor and the battery is equal to the voltage of the fourth capacitor and the voltage of the high-voltage battery module The difference between the high-voltage battery module voltage is the battery module voltage with the highest voltage among the first battery module voltage and the second battery module voltage;

The third step is to confirm that the switching state sampling monitoring of the semiconductor non-contact switch is a blocking state, and the switching state sampling monitoring of the first switch and the second switch are both blocking states;

The fourth step is to close the corresponding switch of the high-voltage battery module. The high-voltage battery module is the battery module with the highest voltage among the voltage of the first battery module and the voltage of the second battery module. The switch is a switch that needs to be closed for the power supply output of the battery module, the corresponding switch of the first battery module is the second switch, and the corresponding switch of the second battery module is the first switch;

The fifth step is to close the corresponding switch of the low-voltage battery module when the voltage difference between the first and second batteries reaches a preset range, and the voltage difference between the first and second batteries is the first battery module The difference between the voltage and the voltage of the second battery module, the low-voltage battery module is the battery module with the lowest voltage among the voltage of the first battery module and the voltage of the second battery module;

The sequence and method of switching the two battery modules from series connection to parallel connection when the positive power supply line is at zero current:

The first step is to control the semiconductor non-contact switch to be in an always-blocking state;

The second step is to use the bus capacitor active discharge technology to reduce the voltage of the fourth capacitor until the voltage difference between the capacitor and the battery reaches a preset range. The bus capacitor active discharge technology includes operating multiple inverter bridges inside the motor controller. The conduction and blockage of each power device converts the energy stored in the fourth capacitor into heat energy or heat energy of the motor winding when the power device is turned on and off, so as to reduce the voltage of the fourth capacitor technology;

The fourth step is to close the corresponding switch of the high-voltage battery module;

Step 5: When the current of the positive power supply line is in the positive current direction, the voltage of the high-voltage battery module drops, and when the voltage difference between the first and second batteries reaches a preset range, then close the low-voltage battery module. The corresponding switch of the voltage battery module.

The technical solution of the fifth aspect proposes an operation method for the electric propulsion system described in the technical solution of the second aspect, and the method includes:

The series-parallel switching instruction of the two battery modules is generated by the autonomous intelligent mode of the control circuit unit in the technical solution of the second aspect or by the passive receiving mode of the control circuit unit in the technical solution of the second aspect,

The autonomous intelligent mode takes the real-time speed of the motor and the series-parallel state of the two battery modules as input conditions, and autonomously and intelligently generates the series-parallel switching command according to the speed hysteresis comparison rule, and the real-time speed of the motor is The actual current rotational speed of the motor is received in real time through the communication port of the control circuit unit in the technical solution of the second aspect. The series-parallel connection state of the two battery modules includes a series state, a parallel state, and a state in the process of switching. The speed hysteresis comparison rule includes: firstly, two motor speed values N1 and two speed values N2 are preset based on the principle of optimizing the loss of the electric drive system, and the motor speed value N1 and the motor speed value N2 can be determined according to the The series-parallel state of the two battery modules and the real-time dynamic calculation and update of the fourth capacitor voltage, or preset the fixed motor speed value N1 and the motor speed according to the series-parallel state of the two battery modules value N2, the motor speed value N1 is always smaller than the motor speed value N2; then, when the real-time speed of the motor exceeds the motor speed value N2, and the two battery modules are currently in the parallel state , then automatically generate a switching instruction to switch the current parallel connection state of the two battery modules to a series connection, otherwise maintain the original series-parallel state, when the real-time speed of the motor is lower than the motor speed value N1, and the The two battery modules are currently in the series connection state, automatically generating a switching instruction for switching the current series connection state of the two battery modules to a parallel connection state, otherwise maintaining the original series-parallel state;

The passive receiving mode: the communication port of the control circuit unit in the technical solution of the second aspect receives the serial-parallel switching instruction of the two battery modules sent by the motor controller through the communication bus;

According to the series-parallel switching instruction of the two battery modules, the two battery modules of the electric propulsion system are configured to be connected in series or in parallel, so that the motor controller of the electric propulsion system can select Supporting capacitor voltage in series state or parallel state supporting capacitor voltage, thereby reducing the loss of the electric propulsion system, and at the same time realizing that the electric propulsion system has no power when the two battery modules are switched between series and parallel. The function of output interruption, the series state support capacitor voltage is the output current of the two battery modules in the series connection state through the closed main positive relay and the main negative relay, the fuse, the The steady-state voltage value of the positive power supply line and the negative power supply line on the fourth capacitor, the parallel state support capacitor voltage is the output current of the two battery modules in the parallel connection state through the closed Steady-state voltage values of the main positive relay, the main negative relay, the fuse, the positive power line and the negative power line on the fourth capacitor.

Beneficial effect

The circuit of the technical solution in the first aspect provides a freewheeling circuit of the self-inductive positive current on the positive and negative pole lines of the power supply, which eliminates the overshoot voltage borne by both ends of each switch at the moment the switch is turned off and the arc flashover and Corrosion; the application of semiconductor non-contact switch greatly reduces the time from receiving the closing or opening command to completing the closing or opening action, which provides a device basis for the uninterrupted power output of the battery pack; the circuit cleverly utilizes the power supply The self-inductance, diode and semiconductor non-contact switch on the positive and negative lines provide the hardware basis of the step-down circuit, provide a hardware basis for eliminating the impact of large currents, and further provide a hardware basis for the uninterrupted power output of the battery pack;

The electric propulsion system of the technical solution in the second aspect provides the hardware system basis for no power output interruption when the battery modules are switched between series and parallel, so that the electric propulsion system has low loss performance and uninterrupted power propulsion performance;

The vehicle in the technical solution of the third aspect overcomes the problem of power interruption caused by the series-parallel switching of two battery packs during acceleration from low speed to high speed, so the vehicle has better power acceleration performance and driving experience; at the same time, the vehicle It can work on two voltage platforms corresponding to the two speed areas during driving in the low-speed area and high-speed area, so that the power consumption of the whole vehicle is lower. And the above-mentioned beneficial effects can not only be harvested in vehicles with an 800V voltage platform composed of two 400V voltage platform batteries connected in series, but also can be obtained in a vehicle with a 400V voltage platform composed of two 200V voltage platform batteries connected in series.

The fourth aspect of the technical solution provides a method for reducing the voltage difference when switching between series and parallel connections, which solves the problem of current impact caused by large voltage differences, and makes switching devices and battery modules safer, more reliable, and longer in service life. It reduces the electromagnetic interference release of the switch circuit; and also provides a low-cost battery pack output continuous adjustable voltage solution;

The method of the technical solution in the fifth aspect provides a simple autonomous series-parallel switching mechanism and a method for reducing the loss of the electric drive system in which the electric propulsion system can work on two voltage platforms, which simplifies the motor controller or the electric propulsion system. The control makes the series-parallel switching circuit easier to use and easier to integrate into the existing battery pack power supply circuit.

Description of drawings

Fig. 1 is an exemplary series-parallel switching main circuit and an exemplary electric propulsion system to which it belongs;

Fig. 2 is several examples in which the switch includes a metal oxide semiconductor field effect transistor or a plurality of metal oxide semiconductor field effect transistors connected in series or in parallel;

Fig. 3 is several examples in which the switch comprises one IGBT or a plurality of IGBTs connected in series or in parallel;

Fig. 4 is a schematic appearance diagram of an embodiment embodied in the form of a power module of a series-parallel switching main circuit;

Fig. 5 is an exemplary series-parallel switching main circuit including absorbing capacitors and an exemplary electric propulsion system to which it belongs;

Fig. 6 is an exemplary diagram embodying the connection relationship between the series-parallel switching main circuit and the control circuit unit and the exemplary electric propulsion system to which it belongs;

7 is an exemplary electric propulsion system including a third inductor;

Fig. 8 is an exemplary main circuit in which three switches all adopt NMOS field-effect transistors and an exemplary electric propulsion system thereof;

Fig. 9 is an explanatory diagram of autonomously and intelligently generating a series-parallel switching instruction according to the speed hysteresis comparison rule.

BEST MODE FOR CARRYING OUT THE INVENTION

A preferred embodiment, as shown in Figure 8, the first switch 101 and the second switch 102 are the implementation form of silicon-based N-channel metal-oxide-semiconductor field-effect transistor single-transistor reverse series connection, the semiconductor non-contact switch 103 It is the realization form of single-transistor reverse series connection of silicon carbide-based N-channel metal-oxide-semiconductor field-effect transistors. Both the first capacitor unit and the second capacitor unit are implemented as a capacitor. The control terminals of the two gate drivers of each switch are respectively electrically coupled to the control circuit unit 200 , the first battery positive terminal 131 , the first battery negative terminal 132 , the second battery positive terminal 133 and the second battery negative terminal 134 They are respectively electrically coupled to the control circuit unit 200, and are input to the control circuit unit 200 through the above four ports. The control circuit unit 200 can realize the sampling and monitoring functions of each battery voltage and the switching state sampling and monitoring functions of the three switches. The first current detection The output port of the device 404 is electrically coupled to the control circuit unit 200 , and the communication port of the control circuit unit 200 is electrically coupled to the communication bus.

As shown in FIG. 8 , the power supply output of the battery pack is electrically coupled to the positive side of the DC bus support capacitor 601 of the motor controller 600 via the main positive relay 401 , the main negative relay 402 , the fuse 403 , the first inductor 501 and the second inductor 502 . negative electrode. The motor controller 600 inverts the DC power on the DC bus support capacitor 601 into multi-phase AC power and outputs it to the motor 700 .

Fig. 8 shows an embodiment of an electric propulsion system, including a main circuit 100, a control circuit unit 200, a first battery module 301, a second battery module 302 and a power supply output circuit, a motor controller 600, and a motor 700 and communication bus.

An embodiment of a method of operating the circuit shown in Figure 8:

The methods include:

Operate the circuit to switch the two battery modules from parallel connection to series connection or from series connection to parallel connection. The drive system works in the non-energy feedback state, and the non-energy feedback state is when the positive power line 501 has a positive current direction or when the positive power line 501 has zero current, the positive power line 501 positive current direction is the discharge current of the two battery modules From the positive port 131 of the first battery to the motor controller 600, the zero current of the positive power line 501 means that the current on the positive power line 501 is zero, and the switching process is from the start moment of the series-parallel switching of the circuit to the completion of the switching The time period of the end moment of ;

The first step is to block the first switch 101 and the second switch 102;

The second step is to confirm that the switch state sampling monitoring of the first switch 101 and the second switch 102 is a blocking state, and the switching state sampling monitoring of the semiconductor non-contact switch 103 is a blocking state;

The third step is to use step-down pulse width modulation method to increase the voltage of the fourth capacitor 601 to the supporting capacitor voltage in series state. The step-down pulse width modulation method is to use semiconductor non-contact switch 103, diode 104, and 501, the second inductance 502 and the fourth capacitor 601 form the step-down circuit, and then control the semiconductor non-contact switch 103 to work alternately in the conduction and blocking states through the control terminal of the semiconductor non-contact switch 103, and gradually rise from zero to High conduction pulse width duty cycle until the voltage of the fourth capacitor 601 is raised to the voltage of the supporting capacitor in the series state, and the voltage of the supporting capacitor in the series state is the output current of the two battery modules in the state of series connection. The main positive relay 401 and the main negative relay 402, 403 fuses, the positive power supply line 501 and the negative power supply line 502 are on the steady-state voltage value of the fourth capacitor 601;

The fourth step is to stop the alternate operation of conduction and blocking of the semiconductor non-contact switch 103 and control the semiconductor non-contact switch 103 to always work in the conduction state;

The sequence and method of switching the two battery modules from series connection to parallel connection include two subdivision methods when the positive power line 501 is in the positive current direction and when the positive power line 501 has zero current:

When the positive power line 501 is in the positive current direction, the sequence and method of switching the two battery modules from series connection to parallel connection:

In the first step, adopt step-down pulse width modulation method 2 to slow down the speed of voltage reduction of the fourth capacitor 601, and gradually reduce the voltage of the fourth capacitor 601 toward the parallel state to support the capacitor voltage. The step-down pulse width modulation method 2 is to use semiconductor The step-down circuit composed of the contactless switch 103, the diode 104, the first inductance 501, the second inductance 502 and the fourth capacitor 601 controls the semiconductor non-contact switch 103 to work alternately through the control terminal of the semiconductor non-contact switch 103 The conduction and blocking states, and gradually reduce the conduction pulse width duty cycle from the maximum conduction pulse width duty cycle, thereby reducing the voltage of the fourth capacitor 601, and the parallel state support capacitor voltage is the voltage of the two battery modules The output current of the group in the parallel connection state passes through the closed main positive relay 401 and the main negative relay 402, the fuse 403, the steady-state voltage value on the fourth capacitor 601 of the positive power supply line 501 and the negative power supply line 502;

In the second step, when the voltage difference of the capacitor battery reaches the preset range, the semiconductor non-contact switch 103 is controlled to be in the blocked state all the time, and the voltage difference of the capacitor battery is the difference between the voltage of the fourth capacitor 601 and the voltage of the high-voltage battery module value, the voltage of the high-voltage battery module is the voltage of the battery module with the highest voltage among the voltage of the first battery module 301 and the voltage of the second battery module 302;

The third step is to confirm that the switching state sampling monitoring of the semiconductor non-contact switch 103 is a blocking state, and the switching state sampling monitoring of the first switch 101 and the second switch 102 are both blocking states;

The fourth step is to close the corresponding switch of the high-voltage battery module. The high-voltage battery module is the battery module with the highest voltage among the voltage of the first battery module 301 and the voltage of the second battery module 302. The corresponding switch is A switch that needs to be closed for power supply output of the battery module, the corresponding switch of the first battery module 301 is the second switch 102, and the corresponding switch of the second battery module 302 is the first switch 101;

The fifth step is to close the corresponding switch of the low-voltage battery module when the voltage difference between the first and second batteries reaches the preset range, and the voltage difference between the first and second batteries is the voltage of the first battery module 301 The difference between the voltage of the second battery module 302 and the low-voltage battery module is the battery module with the lowest voltage among the voltage of the first battery module 301 and the voltage of the second battery module 302;

When the positive power supply line 501 is at zero current, the sequence and method of switching the two battery modules from series connection to parallel connection:

The first step is to control the semiconductor non-contact switch 103 to be in an always-off state;

In the second step, the bus capacitor active discharge technology is used to reduce the voltage of the fourth capacitor 601 until the voltage difference between the capacitor and the battery reaches a preset range. The turning on and off of the device converts the energy stored in the fourth capacitor 601 into heat energy or heat energy of the motor winding when the power device is turned on and off, so as to reduce the voltage of the fourth capacitor 601;

Step 5: When the current of the positive power supply line 501 is in the positive direction, the voltage of the high-voltage battery module drops, and when the voltage difference between the first and second batteries reaches a preset range, the low-voltage battery module is closed again. The corresponding switch of the battery module.

An embodiment of a method of operating the electric propulsion system shown in Figure 8:

The methods include:

The series-parallel switching instruction of the two battery modules is generated by the control circuit unit 200 in the electric propulsion system shown in FIG. 8 in an autonomous intelligent mode or by the control circuit unit 200 in the electric propulsion system shown in FIG. 8 in a passive receiving mode.

The autonomous intelligent mode: taking the real-time rotational speed of the motor 700 and the series-parallel connection state of the two battery modules as input conditions, the series-parallel switching command is autonomously and intelligently generated according to the rotational speed hysteresis comparison rule, and the real-time rotational speed of the motor 600 is as shown in Fig. The communication port of the control circuit unit 200 in the electric propulsion system shown in 8 receives the actual current speed of the motor 700 in real time, and the series-parallel connection state of the two battery modules includes a series state, a parallel state and a state in the process of switching. As shown in FIG. 9 , the speed hysteresis comparison rule includes: firstly, based on the principle of optimizing the loss of the electric drive system, two motor 700 speed values N1 and speed values N2 are preset, and the motor 700 speed value N1 and the motor speed value N2 can be dynamically calculated and updated according to the series-parallel connection state of the two battery modules and the real-time voltage of the fourth capacitor 601, or the fixed motor speed value N1 and the fixed motor speed value N1 can be preset according to the series-parallel connection state of the two battery modules. The motor speed value N2, the motor speed value N1 is always smaller than the motor speed value N2; then, when the real-time speed of the motor 700 exceeds the motor 700 speed value N2, and the two battery modules are currently in the parallel state, then automatically generate a switching instruction to switch the current parallel connection state of the two battery modules to a series connection, otherwise maintain the original series-parallel state, when the real-time speed of the motor 700 is lower than the speed value N1 of the motor 700, and the two battery modules If two battery modules are currently in the series connection state, a switching instruction for switching the current series connection state of the two battery modules to parallel connection is automatically generated, otherwise the original series-parallel state is maintained;

The passive receiving mode: the communication port of the control circuit unit 200 in FIG. 8 receives the series-parallel switching instruction of the two battery modules sent by the motor controller 600 through the communication bus shown;

According to the series-parallel switching instruction of the two battery modules, the two battery modules of the electric propulsion system are configured to be connected in series or in parallel, so that the motor controller 600 of the electric propulsion system can select The ground works in a series state to support the capacitor voltage or a parallel state to support the capacitor voltage, thereby reducing the loss of the electric propulsion system, and at the same time realizing that the electric propulsion system has no power output when the two battery modules are switched between series and parallel. The interrupt function, the series state support capacitor voltage is the output current of the two battery modules in the series connection state through the closed main positive relay 401 and main negative relay 402, fuse 403, positive power supply line 501 and negative pole The steady-state voltage value of the power line 502 on the fourth capacitor 601, the parallel state support capacitor voltage is the output current of the two battery modules in the parallel connection state via the closed main positive relay 401 and main negative relay 402 , the steady-state voltage values of the fuse 403 , the positive power line 501 and the negative power line 502 on the fourth capacitor 601 .

Embodiments of the present invention

The formation and use of some embodiments will be described in detail below in conjunction with the accompanying drawings. The embodiments described herein with respect to the accompanying drawings are illustrative, diagrammatic and are used to provide a basic understanding of the invention. The specific embodiments described are merely illustrative of specific ways to make and use the invention, and do not limit the scope of the invention.

In Fig. 1 of the embodiment of the present invention, the series-parallel switching main circuit 100 shown in Fig. 1 is the basis of the present invention, and the main circuit 100 includes:

the first battery positive terminal 131, which is electrically coupled to the positive terminal of the first battery module 301;

the first battery negative terminal 132, which is electrically coupled to the negative terminal of the first battery module 301;

the second battery positive terminal 133, which is electrically coupled to the positive terminal of the second battery module 302;

the second battery negative terminal 134, which is electrically coupled to the negative terminal of the second battery module 302;

The first switch 101 has a first terminal, a second terminal and at least one control terminal, the first terminal of the first switch 101 and the second terminal of the first switch 101 are electrically coupled to the positive port 131 of the first battery and the second terminal of the first battery. Between the positive terminals 133 of the two batteries, the control terminal of the first switch 101 can configure the first switch 101 to be in a bidirectional current conducting state or a bidirectional current blocking state;

The second switch 102 has a first terminal, a second terminal and at least one control terminal, the first terminal of the second switch 102 and the second terminal of the second switch 102 are electrically coupled to the second battery negative terminal 134 and the second terminal of the second battery. Between a battery negative terminal 132, the control terminal of the second switch 102 can configure the second switch 102 to be in a bidirectional current conducting state or a bidirectional current blocking state;

Diode 104, which is electrically coupled between the positive port 131 of the first battery and the negative port 134 of the second battery, the cathode of the diode 104 is electrically coupled to the positive port 131 of the first battery, and the anode of the diode 104 is electrically coupled to the second battery negative terminal 134;

The semiconductor non-contact switch 103 has a first terminal, a second terminal and at least one control terminal, the first terminal of the semiconductor non-contact switch 103 and the second terminal of the semiconductor non-contact switch 103 are electrically coupled to the first Between the battery negative port 132 and the second battery positive port 133, the semiconductor non-contact switch 103 includes a transistor or a plurality of transistors connected in series or in parallel, and the control terminal of the semiconductor non-contact switch 103 can configure the semiconductor non-contact switch 103 as Bidirectional current conducting state or bidirectional current blocking state. The transistors include Metal Oxide Semiconductor Field Effect Transistor MOSFET, Insulated Gate Bipolar Transistor IGBT and High Electron Mobility Transistor HEMT.

The type of the first switch 101 or the second switch 102 includes a contact switch and a non-contact switch. The contact switch usually includes a relay and a contactor, and the non-contact switch includes a fully controlled power device made of semiconductor materials. It includes transistors and thyristors.

The basic functions of the three switches in the main circuit 100 are as follows. When both the first switch 101 and the second switch 102 are closed and the semiconductor non-contact switch 103 is blocked, the first battery module 301 and the second battery module 302 are Parallel connection; when both the first switch 101 and the second switch 102 are turned off and the semiconductor non-contact switch 103 is turned on, the first battery module 301 and the second battery module 302 are connected in series; when only the first switch 101 When closed, only the positive and negative poles of the second battery module 302 are electrically coupled to the positive terminal 131 of the first battery and the negative terminal 134 of the second battery, and these two terminals are connected in series and parallel for power supply. The positive and negative poles of the output, that is, when only the first switch 101 is closed, only the second battery module 302 supplies power output; when only the second switch 102 is closed, only the positive and negative poles of the first battery module 301 are electrically Coupled to the first battery positive terminal 131 and the second battery negative terminal 134, so only the first battery module 301 supplies power output;

As shown in Figure 1, the power supply output of two battery modules connected in series and parallel is electrically coupled to the motor control via the main positive relay 401, the main negative relay 402, the fuse 403, the positive power line self-inductance 501 and the negative power line self-inductance 502 The positive and negative poles of the DC bus support capacitor 601 of the device 600. The motor controller 600 inverts the DC power on the DC bus support capacitor 601 into multi-phase AC power and outputs it to the motor 700 .

It is not difficult to see that the diode 104, the semiconductor non-contact switch 103, the positive power line self-inductance 501, the negative power line self-inductance 502, and the DC bus support capacitor 601 form a deformed BUCK step-down circuit, and the step-down circuit can The series voltage after the two battery modules are connected in series obtains a voltage value lower than the series voltage on the DC bus support capacitor 601 through the step-down circuit. The product of the duty cycle. In the step-down circuit, the diode 104 and the semiconductor non-contact switch 103 play a key role. When the first switch 101 and the second switch 102 are both in the off state, after the semiconductor non-contact switch 103 is turned on, the two battery modules form a series connection and pass through the self-inductance 501 of the positive power line and the self-inductance 502 of the negative power line. Charging the DC bus support capacitor 601, after a period of on-time, the semiconductor non-contact switch 103 is controlled to be blocked, the positive power line self-inductance 501 current and the negative power line self-inductance 502 current flow through the diode 104 and the stored The energy is released to the DC bus support capacitor 601 . In this way, the semiconductor non-contact switch 103 works alternately at high frequency in the conducting and blocking states until the DC bus support capacitor 601 reaches the pre-controlled voltage value.

The self-inductance 501 of the positive power line and the self-inductance 502 of the negative power line are the self-inductance of the power supply line of the battery pack, so the inductance value is relatively small. 103 needs to work at a higher switching frequency to meet this requirement.

Several preferred implementation forms of the semiconductor non-contact switch 103 include any one of the forms in FIG. 2 . Figure 2a is an N-channel metal-oxide-semiconductor field-effect transistor MOSFET without a body diode. Figure 2b shows two common N-channel metal-oxide-semiconductor field-effect transistor MOSFETs with parasitic diodes in reverse series connection. Fig. 2c is another reverse series connection of two common N-channel MOSFET single transistors with parasitic diodes. Figure 2d and Figure 2e are the parallel forms of Figure 2b and Figure 2c respectively, in order to increase the current capacity, a larger current capacity is required to increase the number of parallel connections. Regardless of the implementation, the control terminal of the semiconductor non-contact switch 103 can finally configure the semiconductor non-contact switch 103 to be in a bidirectional current conducting state or a bidirectional current blocking state.

A further preferred implementation form of the semiconductor non-contact switch 103 is that each N-channel MOSFET in FIG. 2a to FIG. 2e is a silicon carbide-based N-channel MOSFET.

Another realization form of semiconductor non-contact switch 103 is the example shown in Fig. 3a, Fig. 3b, Fig. 3c and Fig. 3d. It can be realized in the form of reverse series connection or parallel connection after series connection of single tubes.

Likewise, preferred implementation forms of the first switch 101 and the second switch 102 may also be any implementation form shown in FIG. 2 or FIG. 3 . The first switch 101 and the second switch 102 preferably adopt non-contact transistors as the realization form, then the conduction and blocking speeds of the first switch 101 and the second switch 102 are greatly improved, and then the series-parallel switching process will be faster, switching The power output of the process is less likely to be interrupted.

FIG. 4 shows a preferred implementation form of the main circuit 100. The main circuit 100 is implemented by a power module, and the power module includes:

A plurality of power terminals, the plurality of power terminals including the first battery positive port 131 terminal, the first battery negative port 132 terminal, the second battery positive port 133 terminal and the second battery negative port 134 terminal of the main circuit 100; Bare chip group, which is integrated inside the power module, the plurality of bare chip groups include the first switch 101 bare chip group of the main circuit 100, the second switch 102 bare chip group, the diode 104 bare chip group and the semiconductor contactless Point switch 103 bare chip group, the multiple bare chip groups are electrically coupled to the multiple power terminals according to the electrical coupling relationship of the main circuit 100, the bare chip group includes one bare chip or a plurality of series or bare die in parallel; and

A plurality of gate drive terminals including at least one drive terminal 151 of the first switch 101 , at least one drive terminal 152 of the second switch 102 and at least one drive terminal 153 of the semiconductor contactless switch 103 .

Further preferably include:

The bare chip set of the first switch 101 includes one metal oxide semiconductor field effect transistor bare chip or a plurality of metal oxide semiconductor field effect transistor bare chips connected in series or in parallel, or the first switch 101 bare chip set includes an insulated gate bipolar A bare transistor die or a plurality of bare die of IGBTs connected in series or in parallel;

The second switch 102 bare chip set includes a metal oxide semiconductor field effect transistor bare chip or a plurality of metal oxide semiconductor field effect transistor bare chips connected in series or in parallel, or the second switch 102 bare chip set includes an insulated gate bipolar A bare transistor die or a plurality of bare die of IGBTs connected in series or in parallel;

The semiconductor non-contact switch 103 bare chip group includes a metal oxide semiconductor field effect transistor bare chip or a plurality of metal oxide semiconductor field effect transistor bare chips connected in series or in parallel, or the semiconductor non-contact switch 103 bare chip group includes an insulating A gate bipolar transistor bare chip or a plurality of series or parallel insulated gate bipolar transistor bare chips, the metal oxide semiconductor field effect transistor bare chip at least includes an N-channel silicon carbide-based metal oxide semiconductor field effect transistor bare chip chip.

The power module further includes:

A substrate, which includes a top metal conductive layer, an insulating layer, and a bottom metal heat transfer layer, the top metal conductive layer is welded to the plurality of bare chip groups;

A heat dissipation metal plate 172, which is used to transfer the heat generated by the plurality of bare chip groups to the outside of the power module, and one side of the heat dissipation metal plate 172 is welded to the metal heat transfer layer on the bottom surface of the substrate;

The housing 171 is used for fixing or connecting the heat dissipation metal plate 172 , the plurality of power terminals, and the plurality of gate-level drive terminals.

In a further embodiment, as shown in FIG. 5 , the main circuit 100 further includes a first capacitor unit 111 and a second capacitor unit 112 at the circuit level, and the first capacitor unit 111 is electrically coupled to the first battery positive port 131 and Between the first battery negative terminal 132 , the second capacitor 112 is electrically coupled between the second battery positive terminal 133 and the second battery negative terminal 134 , and the capacitor unit includes at least one capacitor.

The third capacitor unit 113 is further included. The third capacitor unit 113 is electrically coupled between the first battery negative terminal 132 and the second battery positive terminal 133 . The third capacitor unit 113 includes at least one capacitor.

In a further embodiment, as shown in FIG. 6 , on the basis of the main circuit 100, a circuit control unit 200 is also included, and the functions realized by the control circuit unit 200 include:

providing the drive output required by the main circuit 100;

Voltage sampling monitoring, which includes the voltage sampling monitoring between the first battery positive port 131 and the first battery negative port 132, the voltage sampling monitoring between the second battery positive port 133 and the second battery negative port 134, the first battery positive port Voltage sampling and monitoring between the port 131 and the second battery negative port 134;

Current sampling monitoring, which includes current sampling monitoring between the first battery positive port 131 or the second battery negative port 134 and the motor controller 600,

Switch state sampling monitoring, which includes the switching state sampling monitoring of the first switch 101, the switching state sampling monitoring of the second switch 102 and the switching state sampling monitoring of the semiconductor non-contact switch 103; and

receiving the information including the actual current speed of the motor 700 and the series-parallel switching command, and based on the voltage values monitored by the voltage sampling and the switch states monitored by the switch state sampling, the configuration of the two battery modules is made as Selecting in series or in parallel, and outputting the corresponding drive output signal to the main circuit 100;

As shown in FIG. 6, the control circuit unit 200 includes:

drive output port 1, which is electrically coupled to the control end of the first switch 101;

drive output port 2, which is electrically coupled to the control end of the second switch 102;

drive output port 3, which is electrically coupled to the control end of semiconductor non-contact switch 103;

Voltage sampling input port 1, which is electrically coupled to the first battery positive terminal 131 and the first battery negative terminal 132;

The voltage sampling input port 2 is electrically coupled to the second battery positive port 133 and the second battery negative port 134;

The current sampling input port is electrically coupled to the output port of the first current detection device 404, and the first current detection device 404 detects the current between the first battery positive port 131 or the second battery negative port 134 and the motor controller 600 ;as well as

A communication port, which receives information including the actual current speed of the motor 700 and a series-parallel switching command through an external communication bus, and the process status of the series-parallel switching of the two battery modules and the result status of the switching are passed through the communication port output onto the communication bus.

A further embodiment, as shown in FIG. 6 , on the basis of the main circuit 100 and the circuit control unit 200, further includes:

The first battery module 301, the positive pole of the first battery module is electrically coupled to the first battery positive port 131, and the negative pole of the first battery module 301 is electrically coupled to the first battery negative port 132;

The second battery module 302, the positive pole of the second battery module 302 is electrically coupled to the second battery positive terminal 133, and the negative pole of the second battery module is electrically coupled to the second battery negative terminal 134;

The first inductance 501 includes the self-inductance of the positive power line, and the first inductance 501 is electrically coupled between the positive terminal 131 of the first battery and the positive pole of the DC bus support capacitor 601 of the motor controller 600;

The second inductance 502 includes the self-inductance of the negative power line, and the second inductance 502 is electrically coupled between the negative terminal 134 of the second battery and the negative pole of the DC bus support capacitor 601 of the motor controller 600 ;

The fourth capacitor 601 is the DC bus support capacitor 601 of the motor controller 600. The motor controller 600 inverts the DC power of the two battery modules into multi-phase AC power to drive the motor. The positive pole of the fourth capacitor 601 passes through The first inductor 501 is electrically coupled to the positive pole of the first battery module 301 , the negative pole of the fourth capacitor 601 is electrically coupled to the negative pole of the second battery module 302 via the second inductor 502 ; and

The first current detection device 404 , the first current detection device 404 detects the current between the first battery positive terminal 131 or the second battery negative terminal 134 and the motor controller 600 .

A further embodiment, as shown in Figure 7, further includes:

The third inductor 503 is electrically coupled between the positive terminal of the first battery 131 and the positive electrode of the fourth capacitor 601, and is electrically coupled in series with the first inductor 501, or the third inductor 503 is electrically coupled to the first inductor 503. The negative terminal 134 of the second battery is electrically coupled to the negative terminal of the fourth capacitor 601 and in series with the second inductor 502 .

While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense.

Industrial Applicability

Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention for industrial implementation and use, will be apparent to those skilled in the art upon reference to the description.

Claims

A circuit comprising:

The main circuit is used for series-parallel switching of two battery modules, the two battery modules include a first battery module and a second battery module, and each of the battery modules has a positive pole and a negative pole, The two battery modules can be configured to be connected in series or in parallel by the main circuit, and the positive and negative poles of the two battery modules connected in series or in parallel are connected through the main positive relay, the main negative relay, the fuse, and the positive power line. And the negative power supply line is electrically coupled to an electric drive system including a motor controller and a motor for energy transfer, and the main circuit includes:

a positive terminal of the first battery, which is electrically coupled to the positive terminal of the first battery module;

a first battery negative terminal electrically coupled to the negative terminal of the first battery module;

a second battery positive terminal electrically coupled to the positive terminal of the second battery module;

a second battery negative terminal electrically coupled to the negative terminal of the second battery module;

A first switch, which has a first terminal, a second terminal and at least one control terminal, the first terminal of the first switch and the second terminal of the first switch are electrically coupled to the positive port of the first battery Between the positive terminal of the second battery, the control terminal of the first switch can configure the first switch to be in a bidirectional current conducting state or a bidirectional current blocking state; and

A second switch, which has a first terminal, a second terminal and at least one control terminal, the first terminal of the second switch and the second terminal of the second switch are electrically coupled to the negative terminal of the second battery Between the negative terminal of the first battery, the control terminal of the second switch can configure the second switch to be in a bidirectional current conducting state or a bidirectional current blocking state;

It is characterized in that the main circuit also includes:

a diode, which is electrically coupled between the positive port of the first battery and the negative port of the second battery, the cathode of the diode is electrically coupled to the positive port of the first battery, and the anode of the diode is electrically coupled connected to the negative terminal of the second battery; and

A semiconductor non-contact switch, which has a first terminal, a second terminal and at least one control terminal, the first terminal of the semiconductor non-contact switch and the second terminal of the semiconductor non-contact switch are electrically coupled to the Between the negative terminal of the first battery and the positive terminal of the second battery, the semiconductor non-contact switch includes a transistor or a plurality of transistors connected in series or in parallel, and the control terminal of the semiconductor non-contact switch can be configured with the The semiconductor non-contact switch is in a bidirectional current conduction state or a bidirectional current blocking state.
The circuit according to claim 1, wherein the semiconductor non-contact switch of the main circuit comprises a metal oxide semiconductor field effect transistor or a plurality of metal oxide semiconductor field effect transistors connected in series or in parallel, so The metal oxide semiconductor field effect transistors include at least N-channel silicon carbide-based metal oxide semiconductor field effect transistors.
The circuit according to claim 1, wherein the semiconductor non-contact switch of the main circuit comprises an IGBT or a plurality of IGBTs connected in series or in parallel.
The circuit according to claim 1, wherein the diode of the main circuit is replaced by a transistor or a plurality of transistors connected in series or in parallel, and realize the function of the diode.
The circuit according to claim 1, wherein the first switch and the second switch of the main circuit are both relays or contactors.
The circuit according to claim 5, characterized in that the relay or contactor has the functions of main contact opening and closing state detection and state feedback output, and the corresponding state feedback output port.
The circuit according to claim 1, wherein the first switch and the second switch of the main circuit are non-contact switches, and the non-contact switches include a transistor or a plurality of series or Transistors connected in parallel, the control terminal of the non-contact switch can configure the non-contact switch to be in a bidirectional current conducting state or a bidirectional current blocking state.
The circuit according to claim 7, wherein the main circuit is implemented by a power module, and the power module includes:

a plurality of power terminals, the plurality of power terminals including the first battery positive port terminal, the first battery negative port terminal, the second battery positive port terminal, and the second battery negative port terminal of the main circuit a port terminal; a plurality of bare chip groups integrated inside the power module, the plurality of bare chip groups including the first switch bare chip group, the second switch bare chip group, the The diode bare chip group and the semiconductor non-contact switch bare chip group, the plurality of bare chip groups are electrically coupled to the plurality of power terminals according to the electrical coupling relationship of the main circuit, the bare The chipset includes a single die or multiple die connected in series or in parallel; and

A plurality of gate drive terminals including at least one drive terminal of the first switch, at least one drive terminal of the second switch, and at least one drive terminal of the semiconductor contactless switch.
The circuit of claim 8, wherein

The first switch bare chip group includes a metal oxide semiconductor field effect transistor bare chip or a plurality of metal oxide semiconductor field effect transistor bare chips connected in series or in parallel, or the first switch bare chip group includes an insulated gate double Polarity transistor bare die or multiple series or parallel connection of IGBT bare die;

The second switch bare chip group includes a metal oxide semiconductor field effect transistor bare chip or a plurality of metal oxide semiconductor field effect transistor bare chips connected in series or in parallel, or the second switch bare chip group includes an insulated gate double Polarity transistor bare die or multiple series or parallel connection of IGBT bare die;

The semiconductor contactless switch bare chip set includes a metal oxide semiconductor field effect transistor bare chip or a plurality of metal oxide semiconductor field effect transistor bare chips connected in series or in parallel, or the semiconductor contactless switch bare chip set includes One IGBT bare chip or a plurality of IGBT bare chips connected in series or in parallel, said metal oxide semiconductor field effect transistor bare chip at least including N-channel silicon carbide based metal oxide semiconductor field effect Transistor bare chip.
The circuit according to claim 8 or 9, wherein the power module further comprises:

A substrate, which includes a top metal conductive layer, an insulating layer, and a bottom metal heat transfer layer, the top metal conductive layer is welded to the plurality of bare chip groups;

A heat dissipation metal plate, which is used to transfer the heat generated by the plurality of bare chip groups to the outside of the power module, and one side of the heat dissipation metal plate is welded to the metal heat transfer layer on the bottom surface of the substrate;

The casing is used for fixing or connecting the heat dissipation metal plate, the plurality of power terminals, and the plurality of gate-level drive terminals.
The circuit according to any one of claims 1 to 10, further comprising a first capacitor unit and a second capacitor unit, the first capacitor unit is electrically coupled to the positive port of the first battery and the Between the first battery negative terminal, the second capacitor is electrically coupled between the second battery positive terminal and the second battery negative terminal, and the capacitor unit includes at least one capacitor.
The circuit according to any one of claims 1 to 11, further comprising a third capacitor unit, the third capacitor unit is electrically coupled to the negative port of the first battery and the positive terminal of the second battery Between ports, the third capacitor unit includes at least one capacitor.
The circuit according to any one of claims 1 to 12, further comprising a control circuit unit, the functions realized by the control circuit unit include:

providing the drive output required by the main circuit;

Voltage sampling monitoring, which includes voltage sampling monitoring between the first battery positive port and the first battery negative port, voltage sampling monitoring between the second battery positive port and the second battery negative port, Sampling and monitoring the voltage between the positive terminal of the first battery and the negative terminal of the second battery;

current sampling monitoring, which includes current sampling monitoring between the positive port of the first battery or the negative port of the second battery and the motor controller,

Switch state sampling monitoring, which includes switching state sampling monitoring of the first switch, switching state sampling monitoring of the second switch, and switching state sampling monitoring of the semiconductor non-contact switch; and

receiving information including the actual current speed of the motor and a series-parallel switching instruction, and making configurations of the two battery modules based on the voltage values monitored by the voltage sampling and the switch states monitored by the switch state sampling For the selection of series or parallel connection, and output the corresponding driving output signal to the main circuit;

The control circuit unit includes:

drive output port 1, which is electrically coupled to the control end of the first switch;

drive output port 2, which is electrically coupled to the control end of the second switch;

drive output port 3, which is electrically coupled to the control terminal of the semiconductor non-contact switch;

a voltage sampling input port 1, which is electrically coupled to the positive port of the first battery and the negative port of the first battery;

a voltage sampling input port 2, which is electrically coupled to the positive port of the second battery and the negative port of the second battery;

The current sampling input port is electrically coupled to the output port of the current detection device, and the current detection device detects the current between the first battery positive port or the second battery negative port and the motor controller; as well as

A communication port, which receives information including the actual current speed of the motor and a series-parallel switching command through an external communication bus, and the process status of the series-parallel switching of the two battery modules and the result status of the switching completion are passed through the communication port. port output onto the communication bus.
The circuit according to any one of claims 1 to 13, further comprising:

A first battery module, which is the first battery module, the positive pole of the first battery module is electrically coupled to the positive terminal of the first battery, and the negative pole of the first battery module is electrically coupled connected to the negative terminal of the first battery;

A second battery module, which is the second battery module, the positive pole of the second battery module is electrically coupled to the positive terminal of the second battery, and the negative pole of the second battery module is electrically coupled connected to the negative terminal of the second battery;

a first inductance, which includes the self-inductance of the positive power supply line, and the first inductance is electrically coupled between the positive terminal of the first battery and the positive pole of the DC bus support capacitor of the motor controller;

a second inductance, which includes the self-inductance of the negative power supply line, the second inductance is electrically coupled between the negative terminal of the second battery and the negative pole of the DC bus support capacitor of the motor controller;

The fourth capacitor is the DC bus support capacitor of the motor controller. The motor controller inverts the DC power of the two battery modules into multi-phase AC power to drive the motor. The fourth capacitor The positive pole of the fourth capacitor is electrically coupled to the positive pole of the first battery module via the first inductor, and the negative pole of the fourth capacitor is electrically coupled to the negative pole of the second battery module via the second inductor. ;as well as

A first current detection device, the first current detection device detects the current between the positive terminal of the first battery or the negative terminal of the second battery and the motor controller.
The circuit of claim 14, further comprising:

The third inductor is electrically coupled between the positive terminal of the first battery and the positive terminal of the fourth capacitor, and is electrically coupled in series with the first inductor, or the third inductor is electrically coupled connected between the negative terminal of the second battery and the negative terminal of the fourth capacitor, and electrically coupled in series with the second inductor.
An electric propulsion system comprising:

The circuit of any one of claims 1 to 15;

an electric motor configured to apply torque to its mechanical load;

A motor controller, which is connected to the motor, the positive pole of the DC bus support capacitor of the motor controller is electrically coupled to the positive terminal of the first battery, and the negative pole of the DC bus support capacitor of the motor controller is electrically coupled to to the negative terminal of the second battery;

A communication bus, the motor controller and the circuit are connected through the communication bus for information exchange.
A vehicle, comprising the electric propulsion system according to claim 16, the parallel state support capacitor voltage and the series state support capacitor voltage of the motor controller are the first associated configuration or the second associated configuration; the parallel state support capacitor voltage The output current of the two battery modules in the parallel connection state passes through the closed main positive relay and the main negative relay, the fuse, the positive power line and the negative power line in the The steady-state voltage value on the fourth capacitor; the series state support capacitor voltage is the output current of the two battery modules in the series connection state via the closed main positive relay and the main negative relay, the The steady-state voltage values of the fuse, the positive power supply line and the negative power supply line on the fourth capacitor;

The first association configuration is that the parallel state support capacitor voltage of the motor controller is at least 250V to 450V, and the series state support capacitor voltage of the motor controller is at least 500V to 900V;

The second association configuration is that the parallel state support capacitor voltage of the motor controller is at least 125V to 225V, and the series state support capacitor voltage of the motor controller is at least 250V to 450V.
A method of operating a circuit, the circuit includes a main circuit, and the main circuit is used for switching between series and parallel of two battery modules, the two battery modules include a first battery module and a second battery module, each Each of the battery modules has a positive pole and a negative pole, and the two battery modules can be configured to be connected in series or in parallel by the main circuit, and the positive and negative poles of the two battery modules connected in series or in parallel are connected via The main positive relay, the main negative relay, the fuse, the positive power line and the negative power line are electrically coupled to the electric drive system including the motor controller and the motor for energy transfer, and the main circuit includes: electrically coupled to the The first battery positive port of the positive pole of the first battery module; the first battery negative port electrically coupled to the negative pole of the first battery module; the first battery negative port electrically coupled to the positive pole of the second battery module The second battery positive terminal; the second battery negative terminal electrically coupled to the negative terminal of the second battery module; a first switch having a first terminal, a second terminal and at least one control terminal, and the first switch has a first terminal The first end and the second end of the first switch are electrically coupled between the first battery positive port and the second battery positive port, and the control end of the first switch can configure the first The switch is in a bidirectional current conducting state or a bidirectional current blocking state; a second switch having a first end, a second end and at least one control end, the first end of the second switch and the second end of the second switch Electrically coupled between the negative port of the second battery and the negative port of the first battery, the control terminal of the second switch can configure the second switch to be in a bidirectional current conducting state or a bidirectional current blocking state a diode electrically coupled between the positive port of the first battery and the negative port of the second battery, the cathode of the diode is electrically coupled to the positive port of the first battery, and the anode of the diode is electrically coupled connected to the negative port of the second battery; and a semiconductor non-contact switch having a first terminal, a second terminal and at least one control terminal, the first terminal of the semiconductor non-contact switch and the semiconductor non-contact switch The second terminal is electrically coupled between the negative terminal of the first battery and the positive terminal of the second battery. The semiconductor non-contact switch includes a transistor or a plurality of transistors connected in series or in parallel. The semiconductor non-contact switch The control terminal of the point switch can configure the semiconductor non-contact switch to be in a bidirectional current conducting state or a bidirectional current blocking state,

The circuit further includes a control circuit unit, and the functions realized by the control circuit unit include:

providing the drive output required by the main circuit;

Voltage sampling monitoring, which includes voltage sampling monitoring between the first battery positive port and the first battery negative port, voltage sampling monitoring between the second battery positive port and the second battery negative port, Sampling and monitoring the voltage between the positive terminal of the first battery and the negative terminal of the second battery;

current sampling monitoring, which includes current sampling monitoring between the positive port of the first battery or the negative port of the second battery and the motor controller,

Switch state sampling monitoring, which includes switching state sampling monitoring of the first switch, switching state sampling monitoring of the second switch, and switching state sampling monitoring of the semiconductor non-contact switch; and

receiving information including the actual current speed of the motor and a series-parallel switching instruction, and making configurations of the two battery modules based on the voltage values monitored by the voltage sampling and the switch states monitored by the switch state sampling For the selection of series or parallel connection, and output the corresponding driving output signal to the main circuit;

The control circuit unit includes:

drive output port 1, which is electrically coupled to the control end of the first switch;

drive output port 2, which is electrically coupled to the control end of the second switch;

drive output port 3, which is electrically coupled to the control terminal of the semiconductor non-contact switch;

a voltage sampling input port 1, which is electrically coupled to the positive port of the first battery and the negative port of the first battery;

a voltage sampling input port 2, which is electrically coupled to the positive port of the second battery and the negative port of the second battery;

The current sampling input port is electrically coupled to the output port of the current detection device, and the current detection device detects the current between the first battery positive port or the second battery negative port and the motor controller; as well as

A communication port, which receives information including the actual current speed of the motor and a series-parallel switching command through an external communication bus, and the process status of the series-parallel switching of the two battery modules and the result status of the switching completion are passed through the communication port. port output onto said communication bus;

The circuit further includes:

A first battery module, which is the first battery module, the positive pole of the first battery module is electrically coupled to the positive terminal of the first battery, and the negative pole of the first battery module is electrically coupled connected to the negative terminal of the first battery;

A second battery module, which is the second battery module, the positive pole of the second battery module is electrically coupled to the positive terminal of the second battery, and the negative pole of the second battery module is electrically coupled connected to the negative terminal of the second battery;

a first inductance, which includes the self-inductance of the positive power supply line, and the first inductance is electrically coupled between the positive terminal of the first battery and the positive pole of the DC bus support capacitor of the motor controller;

a second inductance, which includes the self-inductance of the negative power supply line, the second inductance is electrically coupled between the negative terminal of the second battery and the negative pole of the DC bus support capacitor of the motor controller;

The fourth capacitor is the DC bus support capacitor of the motor controller. The motor controller inverts the DC power of the two battery modules into multi-phase AC power to drive the motor. The fourth capacitor The positive pole of the fourth capacitor is electrically coupled to the positive pole of the first battery module via the first inductor, and the negative pole of the fourth capacitor is electrically coupled to the negative pole of the second battery module via the second inductor. ;as well as

a first current detection device, the first current detection device detects the current between the positive terminal of the first battery or the negative terminal of the second battery and the motor controller;

The functions realized by the method include that when the electric drive system is working in the state of the motor outputting positive mechanical power, the method can realize the switching between the series and parallel of the two battery modules without interruption of the motor outputting positive mechanical power , the state of the motor outputting positive mechanical power is represented by the current direction on the positive power supply line flowing from the positive port of the first battery to the motor controller, the method comprising:

Operate the circuit to switch the two battery modules from parallel connection to series connection or from series connection to parallel connection. The drive system works in a non-energy feedback state. When the non-energy feedback state is the positive current direction of the positive power line or when the positive power line has zero current, the positive current direction of the positive power line is the direction of the two battery modules. The discharge current of the group flows from the positive terminal of the first battery to the motor controller, the zero current of the positive power supply line means that the current on the positive power supply line is zero, and the switching process is the start moment of the series-parallel switching of the circuit the time period until the end moment of the handover;

The sequence and method of switching the two battery modules from parallel connection to series connection:

Step 1, disconnecting the first switch and the second switch;

The second step is to confirm that the switching state sampling monitoring of the first switch and the second switch are both blocking states, and the switching state sampling monitoring of the semiconductor non-contact switch is blocking state;

The third step is to use the step-down pulse width modulation method to increase the voltage of the fourth capacitor to the supporting capacitor voltage in a series state. The step-down pulse width modulation method is to use the semiconductor non-contact switch, the diode, The step-down circuit composed of the first inductance, the second inductance and the fourth capacitor controls the semiconductor non-contact switch to work alternately in conduction and resistance through the control terminal of the semiconductor non-contact switch. off state, and gradually increase the on-pulse width duty ratio from zero until the fourth capacitor voltage is raised to the support capacitor voltage in the series state, and the support capacitor voltage in the series state is the voltage of the two battery modules in the The steady-state voltage value of the output current in the series connection state on the fourth capacitor through the closed main positive relay and the main negative relay, the fuse, the positive power supply line and the negative power supply line ;

The fourth step is to stop the alternate operation of conduction and blocking of the semiconductor non-contact switch and control the semiconductor non-contact switch to always work in the conduction state;

The sequence and method of switching the two battery modules from series connection to parallel connection include two subdivision methods when the positive power line is in the positive current direction and when the positive power line is in zero current:

When the positive power line is in the positive current direction, the order and method of switching the two battery modules from series connection to parallel connection:

In the first step, adopt step-down pulse width modulation method 2 to slow down the reduction speed of the fourth capacitor voltage, and gradually reduce the voltage of the fourth capacitor toward the parallel state to support the capacitor voltage, the step-down pulse width modulation method 2 is Utilize the step-down circuit composed of the semiconductor non-contact switch, the diode, the first inductance, the second inductance and the fourth capacitor, and then control the The semiconductor non-contact switch works alternately in the conduction and blocking states, and gradually reduces the conduction pulse width duty cycle from the maximum conduction pulse width duty cycle, thereby reducing the voltage of the fourth capacitor, and the parallel state The supporting capacitor voltage is the output current of the two battery modules connected in parallel through the closed main positive relay and the main negative relay, the fuse, the positive power line and the negative power line A steady-state voltage value on the fourth capacitor;

In the second step, when the voltage difference between the capacitor and the battery reaches a preset range, the semiconductor non-contact switch is controlled to be in a constant blocking state, and the voltage difference between the capacitor and the battery is equal to the voltage of the fourth capacitor and the voltage of the high-voltage battery module The difference between the high-voltage battery module voltage is the battery module voltage with the highest voltage among the first battery module voltage and the second battery module voltage;

The third step is to confirm that the switching state sampling monitoring of the semiconductor non-contact switch is a blocking state, and the switching state sampling monitoring of the first switch and the second switch are both blocking states;

The fourth step is to close the corresponding switch of the high-voltage battery module. The high-voltage battery module is the battery module with the highest voltage among the voltage of the first battery module and the voltage of the second battery module. The switch is a switch that needs to be closed for the power supply output of the battery module, the corresponding switch of the first battery module is the second switch, and the corresponding switch of the second battery module is the first switch;

The fifth step is to close the corresponding switch of the low-voltage battery module when the voltage difference between the first and second batteries reaches a preset range, and the voltage difference between the first and second batteries is the first battery module The difference between the voltage and the voltage of the second battery module, the low-voltage battery module is the battery module with the lowest voltage among the voltage of the first battery module and the voltage of the second battery module;

The sequence and method of switching the two battery modules from series connection to parallel connection when the positive power supply line is at zero current:

The first step is to control the semiconductor non-contact switch to be in an always-blocking state;

The second step is to use the bus capacitor active discharge technology to reduce the voltage of the fourth capacitor until the voltage difference between the capacitor and the battery reaches a preset range. The bus capacitor active discharge technology includes operating multiple inverter bridges inside the motor controller. The conduction and blockage of each power device converts the energy stored in the fourth capacitor into heat energy or heat energy of the motor winding when the power device is turned on and off, so as to reduce the voltage of the fourth capacitor technology;

The third step is to confirm that the switching state sampling monitoring of the semiconductor non-contact switch is a blocking state, and the switching state sampling monitoring of the first switch and the second switch are both blocking states;

The fourth step is to close the corresponding switch of the high-voltage battery module;

Step 5: When the current of the positive power supply line is in the positive current direction, the voltage of the high-voltage battery module drops, and when the voltage difference between the first and second batteries reaches a preset range, then close the low-voltage battery module. The corresponding switch of the voltage battery module.
The method of claim 18, further comprising a method of operating the circuit including the third inductance:

Using the step-down circuit composed of the semiconductor non-contact switch, the diode, the third inductor and the fourth capacitor, the semiconductor non-contact switch is controlled by the control terminal of the semiconductor non-contact switch alternately Working in the conduction and blocking states, the total output voltage of the two battery modules can be stepped down after being connected in series or in parallel, and a continuously adjustable DC voltage can be generated on the fourth capacitor to provide to the The electric drive system outputs positive mechanical power, the total output voltage is the voltage between the positive terminal of the first battery and the negative terminal of the second battery, and the range of the continuously adjustable DC voltage is from zero to the The total voltage is output, and the continuously adjustable DC voltage can be controlled to any voltage value within the variation range.
The method of claim 19, further comprising:

Before the electric drive system works in the energy feedback state, the two battery modules can be quickly configured to be connected in series or in parallel according to the method of claim 19, and then the electric drive system enters the energy feedback state, so The energy feedback state is that the current on the positive power supply line flows from the motor controller to the positive terminal of the first battery.
A method of operating the electric propulsion system of claim 16, the method comprising:

The series-parallel switching instruction of the two battery modules is generated by the autonomous intelligent mode of the control circuit unit in claim 16 or by the passive receiving mode of the control circuit unit in claim 16,

The autonomous intelligent mode: taking the real-time speed of the motor and the series-parallel state of the two battery modules as input conditions, and autonomously and intelligently generating the series-parallel switching command according to the speed hysteresis comparison rule, the real-time speed of the motor is The actual current speed of the motor is received in real time through the communication port of the control circuit unit in claim 16, the series-parallel state of the two battery modules includes a series state, a parallel state, and a state in the process of switching, and the speed is hysteresis The comparison rules include: first, two motor speed values N1 and two speed values N2 are preset based on the principle of optimizing the loss of the electric drive system, and the motor speed value N1 and the motor speed value N2 can be determined according to the two The series-parallel connection state of two battery modules and the dynamic calculation and update of the fourth capacitor voltage in real time, or preset the fixed motor speed value N1 and the motor speed value N2 according to the series-parallel state of the two battery modules. , the motor speed value N1 is always smaller than the motor speed value N2; then, when the real-time speed of the motor exceeds the motor speed value N2, and the two battery modules are currently in the parallel state, then Automatically generate a switching instruction to switch the current parallel connection state of the two battery modules to a series connection, otherwise maintain the original series-parallel state, when the real-time speed of the motor is lower than the motor speed value N1, and the two battery modules When the battery modules are currently in the series connection state, a switching command is automatically generated to switch the current series connection state of the two battery modules to a parallel connection state, otherwise the original series-parallel state is maintained;

The passive receiving mode: the communication port of the control circuit unit in claim 16 receives the series-parallel switching instruction of the two battery modules sent by the motor controller through the communication bus;

According to the series-parallel switching instruction of the two battery modules, the two battery modules of the electric propulsion system are configured to be connected in series or in parallel, so that the motor controller of the electric propulsion system can select Supporting capacitor voltage in series state or parallel state supporting capacitor voltage, thereby reducing the loss of the electric propulsion system, and at the same time realizing that the electric propulsion system has no power when the two battery modules are switched between series and parallel. The function of output interruption, the series state support capacitor voltage is the output current of the two battery modules in the series connection state through the closed main positive relay and the main negative relay, the fuse, the The steady-state voltage value of the positive power supply line and the negative power supply line on the fourth capacitor, the parallel state support capacitor voltage is the output current of the two battery modules in the parallel connection state through the closed Steady-state voltage values of the main positive relay, the main negative relay, the fuse, the positive power line and the negative power line on the fourth capacitor.