All-in-one power supply device, power assembly and electric vehicle

Abstract

The invention discloses an all-in-one power supply device for realizing bridge arm multiplexing, a power assembly and an electric vehicle, and relates to the technical field of new energy automobiles. The all-in-one power supply device comprises a vehicle-mounted charger circuit and a motor driving circuit, wherein the motor driving circuit comprises a three-phase bridge arm and two bus capacitors which are connected in series. The vehicle-mounted charger circuit comprises a primary side circuit and a transformer, a primary side winding of the transformer is used for receiving power supplied by the primary side circuit, one end of a secondary side winding of the transformer is used for being connected with the series connection midpoint of the two bus capacitors, and the other end of the secondary side winding of the transformer is used for being connected with the midpoint of any one of the three-phase bridge arms. In the process of charging the power battery, the vehicle-mounted charger circuit is used for performing power conversion on alternating current output by the alternating current power supply by multiplexing the two bus capacitors and any bridge arm and charging the power battery. According to the invention, the cost and the device size of the all-in-one power supply device are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric vehicles, and more particularly, to a multi-in-one power supply device, power assembly and electric vehicle. BACKGROUND

[0002] With the development of the vehicle industry, the integration of electric vehicle components continues to improve. High integration not only improves the reliability of integrated systems, improves the lightweight design of the vehicle, significantly improves power efficiency and performance, but also effectively reduces costs. Multi-in-one power assemblies have gradually become the industry development trend, and creating a multi-in-one component with deep integration and pursuing extreme cost has become an important focus. Existing multi-in-one products integrate on-board chargers (OBCs), motor control units (MCUs) and other components. The on-board charger and the motor control unit are important components of electric vehicles. In the existing integration scheme of the on-board charger and the motor control unit, physical integration is usually adopted, and different power devices are used for different functions. Considering vehicle driving, the on-board charger does not work, and when the vehicle is charging, the motor control unit does not work, so the utilization rate of power devices is low, resulting in a large size and high cost of the multi-in-one product.

[0003] Therefore, how to reduce the cost and size of the multi-in-one power supply device is a problem to be solved. SUMMARY

[0004] The present application provides a multi-in-one power supply device, power assembly and electric vehicle that realizes bridge arm multiplexing. A bus capacitor of a motor drive circuit and one of the bridge arms are used to form a high-voltage side half-bridge rectifier circuit of an on-board charger circuit, so as to realize multiplexing of power devices of the motor drive circuit and the on-board charger circuit. The system has a simple structure, and the cost and size of the device are reduced.

[0005] In a first aspect, the application provides a multi-in-one power supply device for realizing bridge arm multiplexing, the multi-in-one power supply device comprising a vehicle-mounted charger circuit and a motor drive circuit, the multi-in-one power supply device being configured to realize time-sharing multiplexing of the vehicle-mounted charger circuit and the motor drive circuit, the motor drive circuit comprising three-phase bridge arms and two series-connected bus capacitors, the three-phase bridge arms being respectively configured to be connected to three-phase windings of a drive motor of an electric vehicle, and the two bus capacitors being configured to receive power supply from a power battery. The vehicle-mounted charger circuit comprises a primary circuit and a transformer, the primary circuit being configured to convert input alternating current into direct current, a primary winding of the transformer being configured to receive power supply from the primary circuit, one end of a secondary winding of the transformer being configured to be connected to a series connection midpoint of the two bus capacitors, and the other end of the secondary winding of the transformer being configured to be connected to a midpoint of any one of the three-phase bridge arms. In a process in which the multi-in-one power supply device is used to drive the drive motor, the three-phase bridge arms are configured to receive power supply from the power battery through the two bus capacitors and supply power to the drive motor. In a process in which the multi-in-one power supply device is used to receive alternating current power supply and charge the power battery, the vehicle-mounted charger circuit is configured to perform power conversion on alternating current output by the alternating current power supply through multiplexing of the two bus capacitors and any one of the bridge arms and charge the power battery.

[0006] The motor drive circuit comprises three-phase bridge arms and a bus capacitor bridge arm connected in parallel, the midpoints of the three-phase bridge arms are respectively connected to the three-phase windings of the drive motor, and the bus capacitor is configured to balance bus energy through charging and discharging, suppress voltage fluctuations caused by load mutations and switching actions of power devices, maintain stable direct current bus voltage, form a low-impedance path for alternating current ripples in input direct current by using capacitive reactance characteristics, filter out ripple components generated by rectification residues or high-frequency switching, and reduce current distortion and electromagnetic interference.

[0007] In a process in which the electric vehicle is running, the motor drive circuit is configured to output three-phase alternating current to the drive motor, the two bus capacitors receive current from the power battery and supply power to the three-phase bridge arms, at this time, the three-phase bridge arms and the two bus capacitors are both working, and the vehicle-mounted charger circuit does not need to receive alternating current from the alternating current power supply to charge the power battery, i.e., the vehicle-mounted charger circuit is not working. In a process in which the electric vehicle is charging, the vehicle-mounted charger circuit is configured to receive alternating current power supply and charge the power battery, and the vehicle-mounted charger circuit is working, while the motor drive circuit does not need to supply power to the power battery. Considering that the vehicle-mounted charger is not working when the vehicle is running, and the motor drive circuit is not working when the vehicle is charging, if only simple physical integration is performed, the utilization rate of power devices is low, resulting in a large size and high cost of the multi-in-one product.

[0008] Since the working time of the motor drive circuit and the on-board charger circuit is mutually exclusive, by setting the bus capacitor as two bus capacitors in series, using the two bus capacitors of the motor drive circuit and any one of the three-phase bridge arms, a high-voltage side half-bridge rectifier circuit of the on-board charger circuit is formed, and the motor drive circuit and the on-board charger circuit are time-multiplexed to use part of the power devices. The bridge arm composed of the two bus capacitors is connected across the power battery. The primary circuit of the on-board charger circuit is used to connect the AC power supply and convert the input AC power into DC power, the primary winding of the transformer receives power from the primary circuit and supplies power to the secondary winding, one end of the secondary winding of the transformer is used to connect the midpoint of the series connection of the two bus capacitors, and the other end of the secondary winding of the transformer is used to connect the midpoint of any one of the three-phase bridge arms. During the driving of the electric vehicle, the two bus capacitors receive current from the power battery and supply power to the three-phase bridge arm, and during the charging of the electric vehicle, the on-board charger circuit is used to perform power conversion on the AC power output by the AC power supply through the multiplexing of the two bus capacitors and any one of the bridge arms, and charge the power battery.

[0009] The midpoint of the bridge arm refers to the connection between two electronic devices. For example, the midpoint of any one of the three-phase bridge arms refers to the connection between the two series-connected electronic switching devices, which are composed of insulated gate bipolar transistors and anti-parallel diodes. The electronic switching device can also be composed of other electrical components. The series midpoint of the two bus capacitors refers to the position of the series connection of the two bus capacitors, and the series midpoint is connected to the other end of one bus capacitor and the other end of the other bus capacitor.

[0010] According to the scheme of the present application, by using the two bus capacitors of the motor drive circuit and any one of the three-phase bridge arms to form the half-bridge rectifier circuit of the on-board charger circuit, the power devices of the motor drive circuit and the on-board charger circuit are time-multiplexed, which simplifies the system design, eliminates the need for a separate rectifier circuit, and reduces the size and cost of the multi-in-one power supply device.

[0011] In combination with the first aspect, in some implementations of the first aspect, the other end of the secondary winding of the transformer is used to connect the midpoint of any one of the three-phase bridge arms through the first switch. In the process of using the multi-in-one power supply device to drive the motor, the first switch disconnects the other end of the secondary winding of the transformer from the midpoint of any one of the three-phase bridge arms. In the process of using the multi-in-one power supply device to receive AC power supply and charge the power battery, the first switch connects the other end of the secondary winding of the transformer to the midpoint of any one of the three-phase bridge arms.

[0012] In the process that the all-in-one power supply device is used to receive AC power supply and charge the power battery, since the midpoint of the three-phase bridge arm of the motor driving circuit is directly connected with the three-phase winding of the driving motor, when the on-board charger circuit works, the circuit on the side connected with the power battery, i.e. the high-voltage side, needs to be high-frequency rectified, which can cause high-frequency current on the driving motor, loss and low working efficiency. Therefore, when the on-board charger circuit works, the driving motor needs to be decoupled. In the process that the all-in-one power supply device is used to drive the driving motor, the working frequency of the switch tube on the three-phase bridge arm is low, which can cause the transformer of the on-board charger circuit to be saturated, affecting the safety of the device. Therefore, when the motor driving circuit works, the three-phase bridge arm needs to be decoupled from the transformer of the on-board charger circuit.

[0013] Therefore, by adding the first switch at the connection between the other end of the secondary winding and the midpoint of any one of the three-phase bridge arms, the connection between the other end of the secondary winding and the midpoint of any one of the three-phase bridge arms is controlled by the conduction and turn-off of the first switch. In the process that the all-in-one power supply device is used to drive the driving motor, the first switch is turned off, the transformer of the on-board charger circuit is disconnected from the loop of the three-phase bridge arm, and the transformer is not saturated, thereby decoupling the three-phase bridge arm from the transformer of the on-board charger circuit and avoiding affecting the on-board charger circuit during vehicle driving. In the process that the all-in-one power supply device is used to receive AC power supply and charge the power battery, the first switch is turned on, since the on-board charger circuit only uses one of the three-phase bridge arms for half-bridge rectification, there is no current change in the other two bridge arms, and there is no voltage difference between the three-phase windings of the driving motor. Therefore, during the charging process of the on-board charger circuit for the power battery, there is no high-frequency current in the driving motor, and the connection between the three-phase bridge arm and the driving motor does not need to be disconnected, and the decoupling from the driving motor during charging can also be achieved.

[0014] According to the scheme of the present application, the transformer of the on-board charger circuit and the bridge arm of the motor driving circuit are turned on or turned off by the first switch. During the charging process, the decoupling from the driving motor can be achieved without disconnecting the connection with the driving motor, and during the driving process, the decoupling from the transformer is achieved, avoiding the saturation of the transformer and preventing the damage of the device. The all-in-one power supply device has simple control and low cost.

[0015] In combination with the first aspect, in some implementations of the first aspect, the on-board charger circuit is further configured to convert the direct current output by the power battery into alternating current to supply power to an alternating current load. In the process that the on-board charger circuit is used to supply power to the alternating current load, the on-board charger circuit is configured to convert the direct current output by the power battery into alternating current and perform power conversion to supply power to the alternating current load by multiplexing two bus capacitors and any one bridge arm.

[0016] The on-board charger circuit is also configured to receive power supply from the power battery and convert direct current output by the power battery into alternating current to supply power to the alternating current load. During the process in which the on-board charger circuit is used to supply power to the alternating current load, the motor drive circuit does not need to supply power to the power battery, at this time, the on-board charger circuit multiplexes two bus capacitors and any one of the three-phase bridge arms of the motor drive circuit as a high-voltage side rectifier circuit. The on-board charger circuit multiplexes the two bus capacitors and any one of the three-phase bridge arms to convert the direct current output by the power battery into alternating current and perform power conversion to supply power to the alternating current load.

[0017] According to the scheme of the present application, the motor drive circuit and the on-board charger circuit are time-multiplexed by using the different working time characteristics of the on-board charger circuit and the motor drive circuit, which simplifies the system design, does not need to separately set a rectifier circuit, improves the integration, and reduces the size and cost of the all-in-one power supply device.

[0018] In combination with the first aspect, in some implementations of the first aspect, during the process in which the on-board charger circuit is used to supply power to the alternating current load, the first switch is turned on to connect the other end of the secondary winding of the transformer to the midpoint of any one of the three-phase bridge arms, and the switch tubes of the other bridge arms of the three-phase bridge arms except the any one of the bridge arms are turned off.

[0019] During the process in which the on-board charger circuit is used to supply power to the alternating current load, the circuit on the side connected with the power battery, i.e., the high-voltage side, needs to be high-frequency rectified, which will cause high-frequency current on the driving motor, resulting in loss and thus reducing the working efficiency. Therefore, the on-board charger circuit needs to be decoupled from the driving motor when it is working. During the process in which the on-board charger circuit is used to supply power to the alternating current load, the first switch is turned on, and since the on-board charger circuit only uses one of the three-phase bridge arms for half-bridge rectification, there is no current change in the other two bridge arms, and there is no voltage difference between the three-phase windings of the driving motor. Therefore, during the process in which the on-board charger circuit supplies power to the alternating current load, there is no high-frequency current in the driving motor, and the connection between the three-phase bridge arms and the driving motor does not need to be disconnected, and the decoupling of the driving motor during charging can also be achieved.

[0020] According to the scheme of the present application, the on-board charger circuit and the motor drive circuit are turned on or turned off by the first switch, and during the process in which power is supplied to the alternating current load, the decoupling from the driving motor can be achieved without disconnecting the connection with the driving motor, and the all-in-one power supply device is simple to control and has a low cost.

[0021] In combination with the first aspect, in some implementations of the first aspect, one end of the secondary winding of the transformer is configured to be connected to the midpoint of the series connection of the two bus capacitors through a first capacitor, and the capacity of the first capacitor is smaller than the capacity of the bus capacitor.

[0022] In another implementation, without adding the first switch, only a small-capacitance capacitor is used as the first capacitor connected to one end of the secondary winding of the transformer. One end of the first capacitor is connected to one end of the secondary winding of the transformer, and the other end of the first capacitor is connected to the midpoint of the series connection of the two bus capacitors. The capacitance of the first capacitor is small, and is smaller than the capacitance of the bus capacitors. The capacitance of the first capacitor is determined according to the working frequency of the switch tube of the vehicle charger circuit and the three-phase bridge arm.

[0023] By using a small-capacitance capacitor at the connection between one end of the secondary winding and the midpoint of the series connection of the two bus capacitors, the protection of the circuit can be achieved without additional switches. In the process of using the all-in-one power supply device to drive the motor, the frequency of the switch tube of the three-phase bridge arm is low, and the frequency of the switch tube of the bridge arm connected to the transformer is low. Since the capacitance of the first capacitor is small, the impedance is high, and the first capacitor plays a role of isolation, so that the transformer will not be saturated. The gain of the vehicle charger circuit is low at low frequency, and the devices on the primary side of the vehicle charger circuit will not be damaged, for example, the capacitor included in the primary side circuit will not be overvoltage. The isolation effect of the first capacitor is equivalent to decoupling the three-phase bridge arm and the transformer of the vehicle charger circuit, avoiding the impact on the vehicle charger circuit during vehicle driving.

[0024] In the process of using the all-in-one power supply device to receive an alternating current power supply and charge the power battery, the vehicle charger circuit performs high-frequency rectification, and the frequency is high. Since the capacitance of the first capacitor is small, the impedance is low, and the first capacitor does not play a role of isolation, so that the transformer and the two bus capacitors are normally conducted. At the same time, since the vehicle charger circuit only uses one of the three-phase bridge arms for half-bridge rectification, there is no current change in the other two bridge arms, and there is no voltage difference between the three-phase windings of the motor, so that during the charging process of the vehicle charger circuit for the power battery, there is no high-frequency current in the motor, and the connection between the three-phase bridge arm and the motor does not need to be disconnected, and the motor can be decoupled during charging.

[0025] According to the scheme of the present application, by using a low-capacitance capacitor, the protection of the vehicle charger circuit and the three-phase bridge arm can be achieved without adding additional switches or devices, and the all-in-one power supply device is simple to control, reducing the size and cost.

[0026] In combination with the first aspect, in some implementations of the first aspect, the vehicle charger circuit is further configured to convert the direct current output by the power battery into alternating current to supply power to the alternating current load. In the process of using the vehicle charger circuit to charge the power battery, the switch tubes of the other bridge arms of the three-phase bridge arm except for the arbitrary one are disconnected. In the process of using the vehicle charger circuit to supply power to the alternating current load, the switch tubes of the other bridge arms of the three-phase bridge arm except for the arbitrary one are disconnected.

[0027] When the on-board charger circuit is working, the electric vehicle is in a charging or discharging state, and the electric vehicle needs to be kept stationary, at which time the driving motor should be kept from outputting torque, and at the same time, when the on-board charger circuit is working, the circuit on the side connected with the power battery, i.e. the high-voltage side, needs to be high-frequency rectified, which will cause high-frequency current to be generated on the driving motor, resulting in loss and thus a decrease in working efficiency. Therefore, when the on-board charger circuit is working, the driving motor needs to be decoupled. Therefore, in the process in which the on-board charger circuit is used to charge the power battery or supply power to an alternating-current load, the other two phase arms of the three-phase bridge arm, except for the one phase arm that is reused, should be disconnected, and the switching tubes on the other two phase arms should be turned off to avoid the current path with the reused one phase arm, so that the current in the three-phase winding of the driving motor changes, which affects the driving motor.

[0028] According to the scheme of the present application, when the on-board charger circuit is working, the other bridge arms of the three-phase bridge arm, except for the reused bridge arm, are disconnected, which avoids affecting the driving motor and improves the safety and usability of the all-in-one power supply device.

[0029] In combination with the first aspect, in some implementations of the first aspect, in the process in which the all-in-one power supply device is used to drive the driving motor, the switching tubes of any one bridge arm and the other bridge arms of the three-phase bridge arm work at a first frequency. In the process in which the on-board charger circuit is used to charge the power battery, the switching tubes of any one bridge arm work at a second frequency, and the first frequency is smaller than the second frequency.

[0030] In the process in which the all-in-one power supply device is used to drive the driving motor, the frequency of the switching tubes of the three-phase bridge arm is low, and the frequency of the switching tubes of the one bridge arm connected with the transformer is low. In the process in which the all-in-one power supply device is used to receive alternating-current power supply and charge the power battery, the on-board charger circuit performs high-frequency rectification, and the frequency is high.

[0031] It should be understood that, in the scheme in which a low-capacity capacitor is used, the isolation or filtering effect of the first capacitor is achieved by working at different frequencies. Since there is no additional switching control to switch the working mode, when the all-in-one power supply device switches between different modes of supplying power to the driving motor or charging the power battery, the working frequency of the switching tubes of the reused one bridge arm needs to be changed.

[0032] According to the scheme of the present application, the switching between different modes of the all-in-one power supply device is achieved by changing the working frequency of the switching tubes of the reused one bridge arm, which is simple to control, simplifies the system design, does not need to separately set a switching circuit, improves the integration, and reduces the size and cost of the all-in-one power supply device.

[0033] With reference to the first aspect, in some implementations of the first aspect, during the process in which the on-board charger circuit is used to supply power for the alternating current load, the switch tube of any one bridge arm operates at a third frequency, and the first frequency is less than the third frequency.

[0034] According to the scheme of the present application, the switching between different modes of the all-in-one power supply device is realized by changing the operating frequency of the switch tube of the multiplexed one bridge arm, the control is simple, the system design is simplified, a separate switching circuit is not needed, the integration is improved, and the volume and cost of the all-in-one power supply device are reduced.

[0035] With reference to the first aspect, in some implementations of the first aspect, the voltage resistance value of the first capacitor is greater than the output voltage of the power battery.

[0036] In order to prevent damage to the first capacitor, the selection of the first capacitor also needs to consider the voltage resistance value. The size of the voltage resistance value of the first capacitor is determined based on the output voltage of the power battery and the output power of the on-board charger circuit.

[0037] According to the scheme of the present application, the capacitor with a high voltage resistance value is selected as the first capacitor, and the durability and safety of the all-in-one power supply device are improved.

[0038] With reference to the first aspect, in some implementations of the first aspect, the first switch is a single-pole single-throw switch, one end of the single-pole single-throw switch is used to connect the other end of the secondary winding of the transformer, and the other end of the single-pole single-throw switch is used to connect the midpoint of any one bridge arm.

[0039] The first switch is a single-pole single-throw relay, one end of the single-pole single-throw switch is used to connect the other end of the secondary winding of the transformer, and the other end of the single-pole single-throw switch is used to connect the midpoint of any one bridge arm. The single-pole single-throw relay only needs to pass the current of the transformer of the on-board charger, and the current is much lower than the power current of the driving motor, so a lower specification device can be selected between the transformer and one bridge arm.

[0040] According to the scheme of the present application, only one single-pole single-throw relay needs to be added to realize the control and protection of the all-in-one power supply device, the current passing demand is small, the volume and cost of the first switch are greatly reduced, and the volume and cost of the all-in-one power supply device are reduced.

[0041] With reference to the first aspect, in some implementations of the first aspect, the all-in-one power supply device further includes a housing, the housing is used to accommodate the electrical components of the on-board charger circuit and the motor driving circuit, and the housing is also used to accommodate the first switch.

[0042] The first switch is arranged in the housing of the all-in-one power supply device, and no additional switching module device needs to be arranged outside the all-in-one power supply device.

[0043] According to the scheme of the present application, only one single-pole single-throw relay needs to be added in the multi-in-one power supply device shell to control and circuit protection, the volume and cost of the first switch are small, and the volume and cost of the multi-in-one power supply device are reduced.

[0044] In a second aspect, the present application provides a power assembly, comprising a driving motor and the multi-in-one power supply device in the first aspect and various implementation manners, the multi-in-one power supply device being configured to receive power supply of a power battery to drive the driving motor.

[0045] In a third aspect, the present application provides an electric vehicle, comprising four wheels, a power battery, and the power assembly in the second aspect, the power assembly being configured to receive power supply of the power battery to drive the four wheels.

[0046] The beneficial effects of other aspects can refer to the beneficial effects described in the first aspect, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a schematic diagram of an electric vehicle provided by an embodiment of the present application;

[0048] Figure 2 is a schematic diagram of a circuit of a multi-in-one power supply device provided by an embodiment of the present application;

[0049] Figure 3 is a schematic diagram of a multi-in-one power supply device provided by an embodiment of the present application;

[0050] Figure 4 is a schematic diagram of a circuit structure of a multi-in-one power supply device provided by an embodiment of the present application;

[0051] Figure 5 is a schematic diagram of another circuit structure of a multi-in-one power supply device provided by an embodiment of the present application;

[0052] Figure 6 is a schematic diagram of another circuit structure of a multi-in-one power supply device provided by an embodiment of the present application;

[0053] Figure 7 is a schematic diagram of another circuit structure of a multi-in-one power supply device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0054] The technical solutions in the present application will be described below with reference to the drawings. The detailed description of the following embodiments and the drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described embodiments.

[0055] Figure 1 is a schematic diagram of an electric vehicle 10 architecture provided by an embodiment of the present application.

[0056] As shown in Figure 1 The electric vehicle 10 includes four wheels, a power battery 20, and a power assembly 30, wherein the power assembly 30 includes a multi-in-one power supply device 40 and a drive motor 50. During charging of the electric vehicle 10, the power assembly 30 is configured to receive alternating current and convert the alternating current into direct current to charge the power battery 20. During driving of the electric vehicle 10, the power assembly 30 is configured to receive direct current of the power battery 20 and supply power to the drive motor 50 to drive the four wheels.

[0057] With the development of the vehicle industry, the integration of electric vehicle components continues to improve. High integration not only improves the reliability of the integrated system, but also improves the lightweight design of the vehicle, significantly improves the power efficiency and performance, and effectively reduces the cost. Multi-in-one power assembly has gradually become the industry development trend, and creating a multi-in-one component with deep integration and pursuing extreme cost has become an important focus. The existing multi-in-one product integrates on-board chargers (OBCs), motor control units (MCUs), and other components. The on-board charger and the motor control unit are important components of the electric vehicle. In the existing integration scheme of the on-board charger and the motor control unit, physical integration is usually adopted, and different power devices are used for different functions. Considering the driving of the vehicle, the on-board charger does not work, and the motor control unit does not work when the vehicle is charging. Therefore, the utilization rate of the power device is low, resulting in a large size and high cost of the multi-in-one product.

[0058] Figure 2 A circuit schematic diagram of a multi-in-one power supply device. As shown in Figure 2 The multi-in-one power supply device includes an on-board charger circuit and a motor drive circuit. The on-board charger circuit is configured to receive an alternating current power supply and charge a power battery of an electric vehicle. The on-board charger circuit includes a primary side circuit, a transformer, and a secondary side rectifier circuit. The primary side circuit is configured to convert input alternating current into direct current. The transformer is configured to receive the direct current output by the primary side circuit. The secondary side rectifier circuit is configured to receive the current output by the transformer and perform power conversion and rectification. The motor drive circuit is configured to receive a power supply from the power battery and supply power to a drive motor of the electric vehicle. The motor drive circuit includes three-phase bridge arms connected in parallel and a bus capacitor. The midpoints of the three-phase bridge arms are respectively connected to three-phase windings of the drive motor. The bus capacitor is configured to balance the bus energy through charging and discharging, suppress voltage fluctuations caused by load mutations and switching actions of power devices, maintain the stability of the direct current bus voltage, form a low impedance path for alternating current ripples in the input direct current using capacitive reactance characteristics, filter out ripple components generated by rectification residues or high-frequency switching, and reduce current distortion and electromagnetic interference.

[0059] In one possible implementation, the motor controller and charger share some components in a time-sharing manner, adding an additional switching module for circuit function switching. This additional switching module includes a double-pole double-throw switch. The switching module is required to handle the motor's power current when driving the motor. Considering that many current motors exceed 72kW in power, the switching module needs to handle a current greater than 100A, resulting in a larger size and higher cost for the all-in-one product.

[0060] Based on the above problems and the circuit of the multi-in-one power supply device, this application provides a multi-in-one power supply device, powertrain and electric vehicle that realizes bridge arm reuse. It uses the bus capacitor of the on-board charger circuit and one of the bridge arms to form the high-voltage side half-bridge rectifier circuit of the on-board charger circuit, realizing the reuse of power devices between the motor drive circuit and the on-board charger circuit. The system structure is simple and reduces cost and device size.

[0061] Figure 3 This application provides an embodiment of an all-in-one power supply device 40, which includes a housing for accommodating a circuit board for carrying electrical components of an on-board charger circuit 42 and a motor drive circuit 43.

[0062] In this application, the motor drive circuit 43 is also referred to as the motor controller.

[0063] In one embodiment, the housing further includes a power battery interface for connecting the power battery 20 of the electric vehicle 10 and an external interface for connecting an AC load or an AC power source. The multi-function power supply device 40 is used to receive AC power from the AC power source or to supply power to the AC load through the external interface. The multi-function power supply device 40 is also used to charge the power battery 20 or receive power from the power battery 20 through the power battery interface.

[0064] Figures 4 to 7 This is a schematic diagram of the circuit structure of the all-in-one power supply device 40 provided in the embodiments of this application. Figure 5 and Figure 6 The all-in-one power supply device 40 includes a first switch 423.

[0065] See Figures 4 to 7, the all-in-one power supply device 40 includes an on-board charger circuit 42 and a motor drive circuit 43, the all-in-one power supply device 40 is used to realize time-sharing multiplexing of the on-board charger circuit 42 and the motor drive circuit 43, the motor drive circuit 43 includes a three-phase bridge arm and two series bus capacitors, the three-phase bridge arm is used to connect the three-phase winding of the drive motor 50 of the electric vehicle 10 respectively. The two series bus capacitors are bus capacitor C1 and bus capacitor C2 respectively, and the two series bus capacitors are used to receive power supply of the power battery 20. One end of the bus capacitor C1 is used to be connected with one end of the power battery 20 of the electric vehicle 10, the other end of the bus capacitor C1 is used to be connected with one end of the bus capacitor C2, and the other end of the bus capacitor C2 is used to be connected with the other end of the power battery 20.

[0066] The on-board charger circuit 42 includes a primary circuit 421 and a transformer 422, the primary circuit 421 is used to convert input alternating current into direct current, the primary winding of the transformer 422 is used to receive power supply of the primary circuit 421, one end of the secondary winding of the transformer 422 is used to connect the series midpoint of the two bus capacitors, and the other end of the secondary winding of the transformer 422 is used to connect the midpoint of any one of the three-phase bridge arms.

[0067] Wherein, in the process that the all-in-one power supply device 40 is used to drive the drive motor 50, the three-phase bridge arm is used to receive power supply of the power battery 20 through the two bus capacitors and supply power for the drive motor 50. In the process that the all-in-one power supply device 40 is used to receive alternating current power supply and charge the power battery 20, the on-board charger circuit 42 is used to perform power conversion on the alternating current output by the alternating current power supply through multiplexing of the two bus capacitors and any one of the bridge arms and charge the power battery 20.

[0068] In the process of driving the electric vehicle 10, the motor drive circuit 43 is used to output three-phase alternating current to the drive motor 50, the two bus capacitors receive current from the power battery 20 and supply power for the three-phase bridge arm, at this time, the three-phase bridge arm and the two bus capacitors are both working, and the on-board charger circuit 42 does not need to receive alternating current of the alternating current power supply to charge the power battery 20, that is, the on-board charger circuit 42 does not work. In the process of charging the electric vehicle 10, the on-board charger circuit 42 is used to receive alternating current power supply and charge the power battery 20, the on-board charger circuit 42 works, and the motor drive circuit 43 does not need to supply power to the power battery 20. Considering that the on-board charger does not work when the whole vehicle is driving, and the motor drive circuit 43 does not work when the whole vehicle is charging, if it is simply physically integrated, the power device utilization rate is low, resulting in that the all-in-one product is large in size and high in cost.

[0069] Since the working time of the motor drive circuit 43 and the on-board charger circuit 42 is mutually exclusive, by setting the bus capacitor as two bus capacitors in series, using the two bus capacitors of the motor drive circuit 43 and any one of the three-phase bridge arms, a high-voltage side half-bridge rectifier circuit of the on-board charger circuit 42 is formed, realizing time-sharing multiplexing of part of the power devices of the motor drive circuit 43 and the on-board charger circuit 42. The bridge arm composed of the two bus capacitors is connected across the power battery 20. The primary circuit 421 of the on-board charger circuit 42 is used to connect an alternating current power supply and convert the input alternating current into direct current, the primary winding of the transformer 422 receives power supply from the primary circuit 421 and supplies power to the secondary winding, one end of the secondary winding of the transformer 422 is used to connect the series midpoint of the two bus capacitors, and the other end of the secondary winding of the transformer 422 is used to connect the midpoint of any one of the three-phase bridge arms. In the embodiment of the application, the series midpoint of the two bus capacitors is the series point of the two bus capacitors, specifically, the series midpoint of the two bus capacitors can be one end of the bus capacitor C1 used to connect the bus capacitor C2, or one end of the bus capacitor C2 used to connect the bus capacitor C1, or any point on the wire connecting the bus capacitor C1 and the bus capacitor C1.

[0070] During the driving of the electric vehicle 10, the two bus capacitors receive current from the power battery 20 and supply power to the three-phase bridge arms, and during the charging of the electric vehicle 10, the on-board charger circuit 42 is used to perform power conversion on the alternating current output by the alternating current power supply through the multiplexing of the two bus capacitors and any one of the bridge arms, and charge the power battery 20. At the same time, since the power of the motor drive circuit 43 is large, the current flowing through a single bridge arm is also sufficient for the on-board charger circuit 42 to use.

[0071] According to the scheme of the application, by splitting the bus capacitor of the motor drive circuit 43 into two bus capacitors, the two bus capacitors and any one of the three-phase bridge arms form a half-bridge rectifier circuit of the on-board charger circuit 42, realizing time-sharing multiplexing of power devices of the motor drive circuit 43 and the on-board charger circuit 42, simplifying system design, without the need to separately set a rectifier circuit, reducing the volume and cost of the multi-in-one power supply device 40.

[0072] In one implementation manner, as Figure 5As shown, the other end of the secondary winding of the transformer 422 is used to connect the midpoint of any one of the three-phase bridge arms through the first switch 423. In the process that the multi-in-one power supply device 40 is used to drive the driving motor 50, the first switch 423 disconnects the connection between the other end of the secondary winding of the transformer 422 and the midpoint of any one of the three-phase bridge arms. In the process that the multi-in-one power supply device 40 is used to receive AC power supply and charge the power battery 20, the first switch 423 connects the other end of the secondary winding of the transformer 422 and the midpoint of any one of the three-phase bridge arms.

[0073] In the process that the multi-in-one power supply device 40 is used to receive AC power supply and charge the power battery 20, since the midpoint of the three-phase bridge arm of the motor driving circuit 43 is directly connected with the three-phase winding of the driving motor 50, when the on-board charger circuit 42 works, the circuit on the side connected with the power battery 20, i.e. the high-voltage side, needs to be high-frequency rectified, which will cause high-frequency current on the driving motor 50, resulting in loss and thus low working efficiency, therefore, when the on-board charger circuit 42 works, it needs to be decoupled with the driving motor 50. In the process that the multi-in-one power supply device 40 is used to drive the driving motor 50, the working frequency of the switch tube on the three-phase bridge arm is low, which can cause the transformer 422 of the on-board charger circuit 42 to be saturated, affecting the safety of the device, therefore, when the motor driving circuit 43 works, the three-phase bridge arm needs to be decoupled with the transformer 422 of the on-board charger circuit 42.

[0074] Therefore, by adding the first switch 423 at the connection between the other end of the secondary winding and the midpoint of any one of the three-phase bridge arms, the connection between the other end of the secondary winding and the midpoint of any one of the three-phase bridge arms is controlled by the conduction and disconnection of the first switch 423. In the process that the multi-in-one power supply device 40 is used to drive the driving motor 50, the first switch 423 is disconnected, the transformer 422 of the on-board charger circuit 42 is disconnected with the loop of the three-phase bridge arm, which will not cause the transformer 422 to be saturated, thereby realizing the decoupling of the three-phase bridge arm and the transformer 422 of the on-board charger circuit 42, avoiding the influence on the on-board charger circuit 42 during the driving of the vehicle. In the process that the multi-in-one power supply device 40 is used to receive AC power supply and charge the power battery 20, the first switch 423 is connected, since the on-board charger circuit 42 only uses one of the three-phase bridge arms for half-bridge rectification, there is no current change in the other two bridge arms, and there is no voltage difference between the three-phase windings of the driving motor 50, therefore, in the process that the on-board charger circuit 42 charges the power battery 20, there is no high-frequency current in the driving motor 50, and the connection between the three-phase bridge arm and the driving motor 50 does not need to be disconnected, and the decoupling of the driving motor 50 during charging can also be realized.

[0075] In one embodiment, the on-board charger circuit 42 is further configured to convert the DC power output from the power battery 20 into AC power to supply AC loads. During the process of supplying AC loads, the on-board charger circuit 42 converts the DC power output from the power battery 20 into AC power and performs power conversion by multiplexing two bus capacitors and any one bridge arm to supply AC loads.

[0076] The on-board charger circuit 42 also receives power from the power battery 20 and converts the DC power output from the power battery 20 into AC power to supply AC loads. While the on-board charger circuit 42 is supplying power to the AC loads, the motor drive circuit 43 does not need to supply power to the power battery 20. At this time, the on-board charger circuit 42 reuses the two bus capacitors and any one of the three-phase bridge arms of the motor drive circuit 43 as a high-voltage side rectifier circuit. The on-board charger circuit 42 reuses the two bus capacitors and any one bridge arm to convert the DC power output from the power battery 20 into AC power and performs power conversion to supply AC loads.

[0077] In one embodiment, during the process of the on-board charger circuit 42 supplying power to the AC load, the first switch 423 connects the other end of the secondary winding of the transformer 422 to the midpoint of any one of the three-phase bridge arms, while the switches of the other bridge arms are disconnected.

[0078] When the on-board charger circuit 42 supplies power to the AC load, the circuit on the high-voltage side connected to the power battery 20 needs to undergo high-frequency rectification. This results in high-frequency current being generated in the drive motor 50, causing losses and reducing efficiency. Therefore, the on-board charger circuit 42 needs to be decoupled from the drive motor 50 during operation. When the on-board charger circuit 42 supplies power to the AC load, the first switch 423 is turned on. Since the on-board charger circuit 42 only uses one of the three-phase bridge arms for half-bridge rectification, and there is no current change in the other two bridge arms, there is no voltage difference between the three-phase windings of the drive motor 50. Therefore, during the on-board charger circuit 42 supplying power to the AC load, there is no high-frequency current in the drive motor 50. It is not necessary to disconnect the three-phase bridge arm from the drive motor 50, thus achieving decoupling from the drive motor 50 during charging.

[0079] In one embodiment, such as Figure 6 As shown, the first switch 423 is a single-pole single-throw switch K1. One end of the single-pole single-throw switch K1 is used to connect to the other end of the secondary winding of the transformer 422, and the other end of the single-pole single-throw switch K1 is used to connect to the midpoint of any bridge arm.

[0080] The first switch 423 is a single-pole single-throw switch K1, one end of the single-pole single-throw switch K1 is used for connecting the other end of the secondary winding of the transformer 422, and the other end of the single-pole single-throw switch K1 is used for connecting the midpoint of any one bridge arm. The single-pole single-throw switch K1 only needs to pass the current of the transformer 422 of the vehicle charger, which is much lower than the power current of the driving motor 50, so that a lower specification device can be selected and arranged between the transformer 422 and the bridge arm.

[0081] According to the scheme of the present application, only one single-pole single-throw switch K1 needs to be added to realize the control and protection of the all-in-one power supply device 40, the current passing demand is small, the volume and cost of the first switch 423 are greatly reduced, and the volume and cost of the all-in-one power supply device 40 are reduced.

[0082] In another implementation manner, as shown in Figure 7 one end of the secondary winding of the transformer 422 is used for connecting the midpoint of the series connection of the two bus capacitors through the first capacitor 424, and the capacity of the first capacitor 424 is smaller than the capacity of the bus capacitor.

[0083] In another implementation manner, without adding the first switch 423, only the first capacitor 424 connected with one end of the secondary winding of the transformer 422 is arranged as a small-capacity capacitor. One end of the first capacitor 424 is connected with one end of the secondary winding of the transformer 422, and the other end of the first capacitor 424 is connected with the midpoint of the series connection of the two bus capacitors. The capacity of the first capacitor 424 is small and is smaller than the capacity of the bus capacitor. The capacity of the first capacitor 424 is determined according to the working frequency of the switch tube of the vehicle charger circuit 42 and the three-phase bridge arm.

[0084] By using a small-capacity capacitor at the connection between one end of the secondary winding and the midpoint of the series connection of the two bus capacitors, the protection of the circuit can be realized without additional switches. In the process of using the all-in-one power supply device 40 to drive the driving motor 50, the frequency of the switch tube of the three-phase bridge arm is low, and the frequency of the switch tube of the bridge arm connected with the transformer 422 is low. Since the capacity of the first capacitor 424 is small, the impedance is high, and the first capacitor 424 plays a role of isolation, the transformer 422 will not be saturated, the gain of the vehicle charger circuit 42 is low at low frequency, and the devices on the primary side circuit 421 of the vehicle charger circuit 42 will not be damaged, for example, the capacitor included in the primary side circuit 421 will not be overvoltage at this time. The isolation effect of the first capacitor 424 is equivalent to decoupling the three-phase bridge arm and the transformer 422 of the vehicle charger circuit 42, so as to avoid affecting the vehicle charger circuit 42 during vehicle driving.

[0085] In the process that the all-in-one power supply device 40 is used to receive AC power supply and charge the power battery 20, the on-board charger circuit 42 carries out high-frequency rectification, and the frequency is high. Since the capacity of the first capacitor 424 is small, the impedance is low, and the first capacitor 424 does not play a role in isolation. The transformer 422 is normally conducted with the two bus capacitors. At the same time, since the on-board charger circuit 42 only uses one bridge arm of the three-phase bridge arm to carry out half-bridge rectification, there is no current change in the other two bridge arms, and there is no voltage difference between the three-phase windings of the driving motor 50. Therefore, in the process that the on-board charger circuit 42 charges the power battery 20, there is no high-frequency current in the driving motor 50, and the connection between the three-phase bridge arm and the driving motor 50 does not need to be disconnected, and the decoupling of the driving motor 50 during charging can be realized.

[0086] According to the scheme of the present application, by using a low-capacity capacitor, the protection of the on-board charger circuit 42 and the three-phase bridge arm can be realized without increasing additional switches or devices, and the all-in-one power supply device 40 is simple to control, and the volume and cost are reduced.

[0087] In an embodiment, the withstand voltage value of the first capacitor 424 is greater than the voltage output by the power battery 20.

[0088] In order to prevent damage to the first capacitor 424, the selection of the first capacitor 424 also needs to consider the withstand voltage value. The size of the withstand voltage value of the first capacitor 424 is determined based on the output voltage of the power battery 20 and the output power of the on-board charger circuit 42.

[0089] In an embodiment, in the process that the on-board charger circuit 42 is used to charge the power battery 20, the switch tubes of the other bridge arms except any one bridge arm in the three-phase bridge arm are disconnected. In the process that the on-board charger circuit 42 is used to supply power to the AC load, the switch tubes of the other bridge arms except any one bridge arm in the three-phase bridge arm are disconnected.

[0090] When the on-board charger circuit 42 is working, the electric vehicle 10 is in a charging or discharging state, and it is necessary to keep the electric vehicle 10 stationary. At this time, the driving motor 50 should not output torque, and at the same time, when the on-board charger circuit 42 is working, the circuit on the side connected with the power battery 20, i.e. the high-voltage side, needs to be rectified at a high frequency, which will cause high-frequency current to be generated on the driving motor 50, resulting in loss and causing the working efficiency to decrease. Therefore, when the on-board charger circuit 42 is working, the driving motor 50 needs to be decoupled. Therefore, in the process that the on-board charger circuit 42 is used to charge the power battery 20 or supply power to the AC load, the other two-phase bridge arms except the one-phase bridge arm that is reused in the three-phase bridge arm should be disconnected, and the switch tubes on the other two-phase bridge arms are disconnected to avoid the current path with the reused one-phase bridge arm, so that the current change in the three-phase windings of the driving motor 50 is avoided, and the driving motor 50 is affected.

[0091] In one embodiment, during the process that the multi-purpose power supply device 40 is used to drive the driving motor 50, the switching tubes of any one bridge arm and the other bridge arms in the three-phase bridge arm work at a first frequency. During the process that the on-board charger circuit 42 is used to charge the power battery 20, the switching tubes of any one bridge arm work at a second frequency, and the first frequency is less than the second frequency.

[0092] In one embodiment, during the process that the on-board charger circuit 42 is used to supply power for the AC load, the switching tubes of any one bridge arm work at a third frequency, and the first frequency is less than the third frequency.

[0093] During the process that the multi-purpose power supply device 40 is used to drive the driving motor 50, the switching tubes of the three-phase bridge arm have a low frequency, and the switching tubes of the bridge arm connected with the transformer 422 have a low frequency. During the process that the multi-purpose power supply device 40 is used to receive the AC power supply and charge the power battery 20 or during the process that the on-board charger circuit 42 is used to supply power for the AC load, the on-board charger circuit 42 performs high-frequency rectification, and the working frequency is high.

[0094] It should be understood that, for the scheme using the low-capacity capacitor, the isolation or filtering effect of the first capacitor 424 is achieved by working at different frequencies, and since there is no additional switching control for switching the working mode, the working frequency of the switching tubes of the multiplexed bridge arm needs to be changed when the multi-purpose power supply device 40 switches between different modes of supplying power for the driving motor 50 or charging the power battery 20.

[0095] According to the scheme of the present application, the switching between different modes of the multi-purpose power supply device 40 is achieved by changing the working frequency of the switching tubes of the multiplexed bridge arm, the control is simple, the system design is simplified, a separate switching circuit is not needed, the integration is improved, and the size and cost of the multi-purpose power supply device 40 are reduced.

[0096] According to the scheme of the present application, the half-bridge rectification circuit of the on-board charger circuit is formed by using the two bus capacitors of the motor driving circuit and any one bridge arm in the three-phase bridge arm, the motor driving circuit and the on-board charger circuit are time-multiplexed power devices, the system design is simplified, a separate rectification circuit is not needed, the size and cost of the multi-purpose power supply device are reduced.

[0097] The above merely describes the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A multi-functional power supply device, characterized in that, The multi-in-one power supply device includes an on-board charger circuit and a motor drive circuit. The motor drive circuit includes a three-phase bridge arm and two bus capacitors connected in series. The midpoints of the three bridge arms are respectively used to connect to the three-phase windings of the drive motor. The two bus capacitors are used to receive power from the power battery. The on-board charger circuit includes a primary circuit and a transformer. The primary circuit is used to convert the input AC power into DC power. The primary winding of the transformer is used to receive power from the primary circuit. One end of the secondary winding of the transformer is used to connect to the midpoint of the series connection of the two bus capacitors, and the other end of the secondary winding of the transformer is used to connect to the midpoint of any one of the three bridge arms. Wherein: During the process of the all-in-one power supply device driving the drive motor, the three-phase bridge arm is used to receive power from the power battery through the two bus capacitors and to supply power to the drive motor. During the process of the all-in-one power supply device receiving AC power and charging the power battery, the on-board charger circuit is used to perform power conversion on the AC power output by the AC power supply and charge the power battery by reusing the two bus capacitors and any one of the bridge arms.

2. The all-in-one power supply device according to claim 1, characterized in that, The other end of the secondary winding of the transformer is used to connect to the midpoint of any one of the three-phase bridge arms via a first switch. During the process of the all-in-one power supply device driving the drive motor, the first switch disconnects the connection between the other end of the secondary winding of the transformer and the midpoint of any one of the three-phase bridge arms. During the process of the all-in-one power supply device receiving AC power and charging the power battery, the first switch connects the other end of the secondary winding of the transformer to the midpoint of any one of the three-phase bridge arms.

3. The all-in-one power supply device according to claim 1 or 2, characterized in that, The on-board charger circuit is also used to convert the DC power output from the power battery into AC power to supply AC loads. During the process of the on-board charger circuit supplying power to the AC load, the on-board charger circuit is used to convert the DC power output from the power battery into AC power by reusing the two bus capacitors and any one of the bridge arms, and to perform power conversion to supply power to the AC load.

4. The all-in-one power supply device according to claim 3, characterized in that, During the process of the on-board charger circuit supplying power to the AC load, the first switch connects the other end of the secondary winding of the transformer to the midpoint of any one of the three-phase bridge arms, while the switches of the other bridge arms (excluding the one mentioned above) are disconnected.

5. The all-in-one power supply device according to claim 1, characterized in that, One end of the secondary winding of the transformer is used to connect to the midpoint of the series connection of the two bus capacitors through a first capacitor, wherein the capacitance of the first capacitor is smaller than the capacitance of the bus capacitors.

6. The all-in-one power supply device according to claim 5, characterized in that, The on-board charger circuit is also used to convert the DC power output from the power battery into AC power to supply AC loads. During the process of the on-board charger circuit charging the power battery, the switching transistors of the other three bridge arms, except for any one of the bridge arms, are disconnected. During the process of the on-board charger circuit supplying power to the AC load, the switching transistors of the other three bridge arms, except for any one of the bridge arms, are disconnected.

7. The multi-function power supply device according to any one of claims 1-6, characterized in that, During the process of the multi-in-one power supply device driving the drive motor, the switching transistors of any one bridge arm and the other bridge arms in the three-phase bridge arm operate at a first frequency. During the process of charging the power battery in the on-board charger circuit, the switching transistor of any one of the bridge arms operates at a second frequency, where the first frequency is less than the second frequency.

8. The all-in-one power supply device according to claim 7, characterized in that, During the process of the on-board charger circuit supplying power to the AC load, the switching transistor of any one of the bridge arms operates at a third frequency, where the first frequency is less than the third frequency.

9. The multi-function power supply device according to any one of claims 5-8, characterized in that, The voltage rating of the first capacitor is greater than the voltage output by the power battery.

10. The multi-function power supply device according to any one of claims 2-4, characterized in that, The first switch is a single-pole single-throw switch. One end of the single-pole single-throw switch is used to connect to the other end of the secondary winding of the transformer, and the other end of the single-pole single-throw switch is used to connect to the midpoint of any one of the bridge arms.

11. The multi-function power supply device according to any one of claims 1-4, characterized in that, The all-in-one power supply device also includes a housing for accommodating the electrical components of the on-board charger circuit and the motor drive circuit, and the housing is also used to accommodate the first switch.

12. A powertrain, characterized in that, The powertrain includes a drive motor and an all-in-one power supply device according to any one of claims 1-11, wherein the all-in-one power supply device is used to receive power from the power battery to drive the drive motor.

13. An electric vehicle, characterized in that, The electric vehicle includes four wheels, a power battery, and the powertrain of claim 12, the powertrain being configured to receive power from the power battery to drive the four wheels.

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