Energy conversion device and safety control method thereof

Abstract

To provide an energy conversion device and a safety control method for the same.SOLUTION: An energy conversion device includes a first switch module (10), a motor inverter (20) which has first and second bus terminals respectively connected to first and second terminals of a battery (70), and in which the first switch module (10) controls ON / OFF of the first bus terminal and the first terminal of the battery (70), or controls ON / OFF of the second bus terminal and the second terminal of the battery, or controls ON / OFF of the first bus terminal and the first terminal of the battery (70) and ON / OFF of the second bus terminal and the second terminal of the battery, a motor winding (30) having a first terminal connected to a midpoint terminal of the motor inverter (20), and a second switch module (40) and a first capacitor (50) which are connected in series, and a first terminal and a second terminal of which are connected to a second terminal of the motor winding (30) and the second bus terminal respectively after the series connection is established.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority from Chinese Patent Application No. "202010501054.1" filed by BD Company Limited on June 4, 2020, entitled "Energy Conversion Device and Safety Control Method Thereof."

[0002] The present application relates to the field of vehicles, and more particularly to an energy conversion device and a safety control method thereof. [Background technology]

[0003] With the widespread use of new energy sources, batteries can be applied in various fields as power sources. However, the environment in which a battery is used as a power source affects its performance. For example, the performance of a battery in a low-temperature environment is significantly lower than that at room temperature. For example, the discharge capacity of a battery at zero temperature decreases as the temperature decreases. At -30°C, the discharge capacity of the battery is essentially zero, making the battery pack unusable. To be able to use a battery in a low-temperature environment, the battery must be heated. Summary of the Invention

[0004] An object of the present application is to provide an energy conversion device and a safety control method thereof that can realize safe control of the energy conversion device.

[0005] An energy conversion device according to a first embodiment of the present application includes: a first switch module; a motor inverter having a first bus terminal connected to a first terminal of a battery and a second bus terminal connected to a second terminal of the battery, wherein the first switch module controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery, or controls on / off between the second bus terminal of the motor inverter and the second terminal of the battery, or controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery and on / off between the second bus terminal of the motor inverter and the second terminal of the battery; a motor winding having a first terminal connected to a midpoint terminal of the motor inverter; a second switch module and a first capacitor connected in series, the first terminal of the second switch module and the first capacitor being connected in series to a second terminal of the motor winding and a second terminal of the second switch module and the first capacitor being connected to a second bus terminal of the motor inverter; a controller configured to control the first switch module to turn off based on a command representing the discharge of an accumulator, thereby disconnecting the battery from the motor inverter, and to control the motor inverter when the second switch module turns on, thereby discharging energy to the first capacitor.

[0006] Preferably, the energy conversion device further includes a second capacitor having a first terminal connected to a first bus terminal of the motor inverter and a second terminal connected to a second bus terminal of the motor inverter; The controller is further configured to control the first switch module to turn off based on a command representing the discharge of the accumulator, thereby disconnecting the battery from the second capacitor and the motor inverter, and to discharge energy to the first capacitor and the second capacitor by controlling the motor inverter when the second switch module is turned on.

[0007] In a safety control method for an energy conversion device according to a second embodiment of the present application, the energy conversion device includes: a first switch module; a motor inverter having a first bus terminal connected to a first terminal of a battery and a second bus terminal connected to a second terminal of the battery, wherein the first switch module controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery, or controls on / off between the second bus terminal of the motor inverter and the second terminal of the battery, or controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery and on / off between the second bus terminal of the motor inverter and the second terminal of the battery; a motor winding having a first terminal connected to a midpoint terminal of the motor inverter; a second switch module and a first capacitor connected in series, the first terminal of the second switch module being connected to a second terminal of the motor winding after being connected in series, and the second terminal of the second switch module being connected to a second bus terminal of the motor inverter; The method includes controlling the first switch module to turn off based on a command representing the discharge of an accumulator, thereby disconnecting the battery from the motor inverter, and controlling the motor inverter to discharge energy to the first capacitor when the second switch module turns on.

[0008] Preferably, the energy conversion device further includes a second capacitor having a first terminal connected to a first bus terminal of the motor inverter and a second terminal connected to a second bus terminal of the motor inverter; The method further includes controlling the first switch module to turn off based on a command representing the discharge of the accumulator, thereby disconnecting the battery from the second capacitor and the motor inverter, and controlling the motor inverter when the second switch module turns on to discharge energy to the first capacitor and the second capacitor.

[0009] Preferably, the step of discharging energy to the first capacitor and the second capacitor by controlling the motor inverter includes: The method includes controlling the motor inverter to discharge energy to the first capacitor, and controlling the motor inverter to discharge energy by the first capacitor to the second capacitor.

[0010] Preferably, the motor inverter includes an upper bridge arm and a lower bridge arm; The step of controlling the motor inverter to discharge energy to the first capacitor includes: The method includes the step of discharging energy to the first capacitor by controlling the upper bridge arm to hold it off and controlling the lower bridge arm to alternately turn on and off.

[0011] Preferably, the step of controlling the motor inverter to discharge energy from the first capacitor to the second capacitor comprises: controlling an upper bridge arm of the motor inverter to turn on, thereby causing the second capacitor to charge the first capacitor; controlling the upper bridge arm to be held off and controlling the lower bridge arm of the motor inverter to be alternately turned on and off, thereby discharging energy from the first capacitor after charging; and repeatedly performing the steps of controlling the upper bridge arm of the motor inverter to turn on and controlling the upper bridge arm to keep it off and controlling the lower bridge arm of the motor inverter to turn on / off alternately until the voltage of the second capacitor becomes lower than a predetermined voltage.

[0012] Preferably, the time it takes for the second capacitor to charge the first capacitor is calibrated based on the type of vehicle, the capacitance value of the first capacitor, and the capacitance value of the second capacitor.

[0013] Preferably, the alternately turning on and off of the lower bridge arm is adjusted by controlling the duty ratio of the lower bridge arm to gradually increase from a first duty ratio to a second duty ratio, and then controlling the duty ratio of the lower bridge arm to gradually decrease from the second duty ratio to the first duty ratio.

[0014] Preferably, when the second switch module is turned on, sintering the second switch module; and After completing charging of the battery using the energy conversion device, controlling the second switch module so that the second switch module is not sintered and is turned on based on a command representing the discharge of the accumulator; After completing self-heating of the battery using the energy conversion device, controlling the second switch module so that the second switch module is not sintered and turns on based on a command representing discharging the accumulator; After realizing a driving function using the energy conversion device, the second switch module is not sintered and controlling the second switch module to turn on based on a command representing the discharge of the accumulator.

[0015] Preferably, the sintering of the second switch module is determined by controlling the second switch module to be off and controlling the first switch module so that the battery is in communication with the motor inverter, controlling a lower bridge arm of the motor inverter to be off and controlling at least one upper bridge arm of the motor inverter to be on, and determining that the second switch module is sintered when current flows through the motor inverter.

[0016] Preferably, the sintering of the second switch module is determined by controlling the second switch module to be on and the first switch module to connect the battery to the motor inverter, controlling a lower bridge arm of the motor inverter to be off and controlling at least one upper bridge arm of the motor inverter to be on, thereby charging the second capacitor with the battery, controlling the second switch module to be off, controlling the upper bridge arm of the motor inverter to be off and controlling at least one lower bridge arm of the motor inverter to be on, and determining that the second switch module is sintered when current flows through the motor inverter.

[0017] The use of the above technical means has the following beneficial effects.

[0018] (1) The energy conversion device in the present application can realize the motor driving function by controlling the second switch module to turn off, and can realize the battery heating function by controlling the second switch module to turn on.

[0019] (2) The energy release of the first capacitor can be achieved by utilizing the interlocking between the components of the energy conversion device itself, and there is no need to add any additional components, thereby reducing the overall cost of the vehicle.

[0020] (3) When the first switch module disconnects the battery from the motor inverter and the second switch module turns on, the motor inverter controls the first capacitor to discharge energy. This solves the high-voltage safety issue of the battery during the first capacitor's energy discharge period. As can be seen from the topology of Figure 1, during the energy discharge period, the first switch module is off and the second switch module is on. Therefore, the energy of the first capacitor is discharged through a circulating circuit consisting of the motor inverter, motor winding, second switch module, and first capacitor. That is, the high-voltage energy of the first capacitor is dissipated through the energy loss caused by the repeated switching operations of the motor inverter, the energy consumption of the motor inverter when it is on, and the heat loss in the motor winding, thereby realizing the energy discharge of the first capacitor. Furthermore, because the discharge current is not large during the discharge process, it is possible to avoid converting the pre-sintering of the second switch module due to a software bug or incomplete sintering caused by the second switch module itself into the firing of the second switch module, thereby avoiding secondary damage to the second switch module.

[0021] Other features and advantages of the present application are described in detail in the following specific embodiments. [Brief explanation of the drawings]

[0022] The drawings provide a further understanding of the present application, constitute a part of the specification, and together with the following specific embodiments illustrate, but do not limit, the present application.

[0023] [Figure 1] 1 is a schematic diagram of a topology structure of an energy conversion device according to an embodiment of the present application; [Figure 2] 1 is a schematic diagram of another topology structure of an energy conversion device according to an embodiment of the present application; [Figure 3]1 is a circuit schematic diagram of an energy conversion device according to an embodiment of the present application. [Figure 4] 2 is a flowchart of a safety control method for an energy conversion device according to an embodiment of the present application. [Figure 5] 4 is another flowchart of a safety control method for an energy conversion device according to an embodiment of the present application. [Figure 6] FIG. 10 is a schematic diagram illustrating the alternating on / off adjustment of the lower bridge arm of the motor inverter. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, specific embodiments of the present application will be described in detail with reference to the drawings. It should be understood that the specific embodiments described herein are merely for the purpose of explaining and interpreting the present application, and are not intended to limit the present application.

[0025] 1 is a schematic diagram of a topology structure of an energy conversion device according to an embodiment of the present application. As shown in FIG. 1, the energy conversion device includes a first switch module 10, a motor inverter 20, a motor winding 30, a second switch module 40, a first capacitor 50, and a controller 60. The dashed lines in FIG. 1 indicate that the controller 60 controls the operations of the first switch module 10, the motor inverter 20, and the second switch module 40 by transmitting control signals to the first switch module 10, the motor inverter 20, the second switch module 40, etc.

[0026] As shown in FIG. 1 , the first bus terminal M1 of the motor inverter 20 is connected to the first terminal of the battery 70, and the second bus terminal M2 of the motor inverter 20 is connected to the second terminal of the battery 70. The first switch module 10 controls the on / off of the first bus terminal M1 of the motor inverter 20 and the first terminal of the battery 70, or controls the on / off of the second bus terminal M2 of the motor inverter 20 and the second terminal of the battery 70, or controls the on / off of the first bus terminal M1 of the motor inverter 20 and the first terminal of the battery 70 and the on / off of the second bus terminal M2 of the motor inverter 20 and the second terminal of the battery 70.

[0027] A first terminal of the motor winding 30 is connected to a midpoint terminal M3 of the motor inverter 20. The second switch module 40 and the first capacitor 50 are connected in series, and first terminals of the second switch module 40 and the first capacitor 50 after being connected in series are connected to a second end of the motor winding 30, and second terminals of the second switch module 40 and the first capacitor 50 after being connected in series are connected to a second bus terminal M2 of the motor inverter 20.

[0028] The controller 60 is configured to control the first switch module 10 to turn off based on a command representing the discharge of the accumulator, thereby disconnecting the battery 70 from the motor inverter 20, and when the second switch module 40 turns on, to control the motor inverter 20 to discharge energy to the first capacitor 50.

[0029] Based on the above energy conversion device, the controller 60 controls the on-state of the first switch module 10, the off-state of the second switch module 40, and the on / off state of the motor inverter 20, so that the battery 70, the first switch module 10, the motor inverter 20, and the motor winding 30 form a motor drive circuit. The controller 60 controls the on-state of the first switch module 10, the on-state of the second switch module 40, and the on / off state of the motor inverter 20, so that the battery 70, the first switch module 10, the motor inverter 20, the motor winding 30, the second switch module 40, and the first capacitor 50 form a battery heating circuit. The battery heating circuit includes four stages, specifically a battery discharge circuit, a motor winding circulation circuit, a motor winding energy storage circuit, and a battery charging circuit. The battery 70 discharges to the first capacitor 50 via the upper bridge arm of the motor inverter 20, the motor winding 30, and the second switch module 40 to form the battery discharge circuit. The motor winding 30 circulates via the second switch module 40, the first capacitor 50, and the lower bridge arm of the motor inverter 20 to form the motor winding circulation circuit. The first capacitor 50 stores energy in the motor winding 30 via the second switch module 40 and the lower bridge arm of the motor inverter 20 to form the motor winding energy storage circuit. The first capacitor 50 discharges to the battery via the second switch module 40, the motor winding 30, and the upper bridge arm of the motor inverter 20 to form the battery charging circuit.

[0030] In the present application, when the second switch module 40 is turned on, it includes at least one of the following:

[0031] (1) The second switch module 40 is sintered. When the second switch module 40 is sintered, the second switch module 40 is in a short-circuit state, and therefore, in this case, the second switch module 40 is considered to be turned on.

[0032] (2) After the external device has completed charging the battery 70 using the energy conversion device according to the embodiment of the present application, the second switch module 40 is not sintered, and the controller 60 controls the second switch module 40 to be turned on based on a command representing the discharge of the accumulator (after the external device has completed charging the battery 70 using the energy conversion device according to the embodiment of the present application, energy remains in the first capacitor 50, and for safety reasons, energy needs to be discharged from the first capacitor 50). In this case, since the second switch module 40 is not sintered, its on / off can still be controlled by the controller 60. Furthermore, when the first capacitor 50 needs to discharge energy, the second switch module 40 can communicate with the energy discharge circuit simply by being in the on state. Therefore, in this case, the controller 60 needs to control the second switch module 40 to be turned on based on a command representing the discharge of the accumulator.

[0033] (3) After the self-heating of the battery 70 is completed using the energy conversion device according to the embodiment of the present application, the second switch module 40 is not sintered, and the second switch module 40 is controlled to turn on based on a command representing the discharge of the accumulator (after the self-heating of the battery 70 is completed using the energy conversion device according to the embodiment of the present application, energy remains in the first capacitor 50, and energy needs to be discharged from the first capacitor 50 for safety reasons). In this case, since the second switch module 40 is not sintered, its on / off can still be controlled by the controller 60. Also, when the first capacitor 50 needs to discharge energy, the second switch module 40 can communicate with the energy discharge circuit simply by being in the on state. Therefore, in this case, the second switch module 40 needs to be controlled to turn on based on a command representing the discharge of the accumulator.

[0034] (4) After the driving function is realized using the energy conversion device according to the embodiment of the present application, the second switch module 40 is not sintered, and the second switch module 40 is controlled to be turned on based on a command representing the discharge of the accumulator (after the driving function is realized using the energy conversion device according to the embodiment of the present application, energy remains in the second capacitor, and for safety reasons, energy needs to be discharged from the second capacitor). In this case, since the second switch module 40 is not sintered, its on / off can still be controlled by the controller 60. Also, when the first capacitor 50 needs to discharge energy, the second switch module 40 can communicate with the energy discharge circuit simply by being in the on state. Therefore, in this case, the second switch module 40 needs to be controlled to be turned on based on a command representing the discharge of the accumulator.

[0035] The use of the above technical means has the following beneficial effects.

[0036] (1) The energy conversion device of the present application can realize the motor driving function by controlling the second switch module 40 to turn it off, and can realize the battery heating function by controlling the second switch module 40 to turn it on.

[0037] (2) The energy release of the first capacitor can be achieved by utilizing the interlocking between the components of the energy conversion device itself, and there is no need to add any additional components, thereby reducing the overall cost of the vehicle.

[0038] (3) When the first switch module 10 turns off the connection between the battery 70 and the motor inverter 20 and the second switch module 40 turns on, the motor inverter 20 controls the first capacitor 50 to release energy. This solves the high voltage safety issue caused by the battery 70 during the energy release period of the first capacitor 50. As can be seen from the topology structure of FIG. 1, during the energy release period, the first switch module 10 is in the off state and the second switch module 40 is in the on state, so the energy of the first capacitor 50 is released through the circulation circuit formed by the motor inverter 20, the motor winding 30, the second switch module 40, and the first capacitor 50. That is, the high voltage energy of the first capacitor 50 is consumed through the energy loss caused by the repeated switching operations of the motor inverter 20, the energy consumption of the motor inverter 20 when it is on, and the heat loss in the motor winding 30, thereby realizing the energy release of the first capacitor 50. Furthermore, since the emission current is not large during the emission process, it is possible to avoid converting the pre-firing of the second switch module 40 due to a software bug or incomplete sintering due to the second switch module 40 itself into the firing of the second switch module 40, thereby avoiding secondary damage to the second switch module 40.

[0039] 2 is a schematic diagram of another topology structure of an energy conversion device according to an embodiment of the present application. As shown in FIG. 2, the energy conversion device further includes a second capacitor 80, a first terminal of the second capacitor 80 is connected to a first bus terminal M1 of the motor inverter 20, and a second terminal of the second capacitor 80 is connected to a second bus terminal M2 of the motor inverter 20.

[0040] The controller 60 is further configured to control the first switch module 10 to turn off based on a command representing the discharge of the accumulator, thereby disconnecting the connection between the battery 70, the second capacitor 80, and the motor inverter 20, and when the second switch module 40 is turned on, to control the motor inverter 20 to discharge energy to the first capacitor 50 and the second capacitor 80. The reason why energy needs to be discharged from the second capacitor 80 is that after the battery 70 is charged using the energy conversion device according to the embodiment of the present application, the battery 70 heats up and achieves its driving function, and high-voltage energy remains in the second capacitor 80, so it is necessary to discharge energy from the second capacitor 80 for safety reasons.

[0041] The energy release from the second capacitor 80 is also achieved by utilizing the interoperability of the components of the energy conversion device itself, eliminating the need for additional components and reducing the overall cost of the vehicle. The principle of energy release from the second capacitor 80 is similar to that for the first capacitor 50 described above, utilizing the energy loss due to repeated switching operations of the motor inverter 20, the energy consumption of the motor inverter 20 when it is on, and the heat loss in the motor windings 30. Therefore, the release current is not large during the release process, which prevents pre-sintering of the second switch module 40 due to a software bug or incomplete sintering due to the second switch module 40 itself from being converted into firing of the second switch module 40, thereby avoiding secondary damage to the second switch module 40.

[0042] 3 is a circuit schematic diagram of an energy conversion device according to an embodiment of the present application. As shown in FIG. 3, the motor inverter 20 includes an N-phase bridge arm, and the motor winding 30 includes N windings, and first terminals of the N windings are connected to the midpoint terminals of the N-phase bridge arms (i.e., positions A, B, and C in FIG. 3) in one-to-one correspondence, where N≧1.

[0043] Continuing to refer to FIG. 3 , the first switch module 10 includes a positive contactor K1 connected between a first terminal of the battery 70 and a first bus terminal of the motor inverter 20, and further includes a negative contactor K2 connected between a second terminal of the battery 70 and a second bus terminal of the motor inverter 20. The positive contactor K1 can disconnect the first terminal of the battery 70 from the first bus terminal of the motor inverter 20, thereby disconnecting the battery 70 from the motor inverter. The negative contactor K2 can disconnect the second terminal of the battery 70 from the second bus terminal of the motor inverter 20, thereby disconnecting the battery 70 from the motor inverter. As will be understood by those skilled in the art, the first switch module 10 may include only the positive contactor K1, only the negative contactor K2, or both the positive and negative contactors K1 and K2.

[0044] Furthermore, as will be further understood by those skilled in the art, the specific structures of the motor inverter 20, the motor winding 30, and the first switch module 10 shown in FIG. 3 are merely exemplary, and the present application does not limit these.

[0045] 4 is a flowchart of a safety control method for an energy conversion device according to an embodiment of the present application. The method can be used to perform energy release for the energy conversion device shown in FIGS. 1 to 3. As shown in FIG. 4, the method includes the following steps S41 to S42.

[0046] In step S41, the connection between the battery 70 and the motor inverter 20 is turned off by controlling the first switch module 10 to turn off based on a command representing the discharge of the accumulator.

[0047] In step S42, when the second switch module 40 is turned on, the motor inverter 20 is controlled to discharge energy to the first capacitor 50.

[0048] In the present application, when the second switch module 40 is turned on, it includes at least one of the following:

[0049] (1) The second switch module 40 is sintered. When the second switch module 40 is sintered, the second switch module 40 is in a short-circuit state, and therefore, in this case, the second switch module 40 is considered to be turned on.

[0050] (2) After the external device has completed charging the battery 70 using the energy conversion device according to the embodiment of the present application, the second switch module 40 is not sintered, and the second switch module 40 is controlled to be turned on based on a command representing the discharge of the accumulator (after the external device has completed charging the battery 70 using the energy conversion device according to the embodiment of the present application, energy remains in the first capacitor 50, and for safety reasons, energy needs to be discharged from the first capacitor 50). In this case, since the second switch module 40 is not sintered, its on / off operation can still be controlled. Furthermore, when the first capacitor 50 needs to discharge energy, the second switch module 40 can communicate with the energy discharge circuit simply by being in the on state. Therefore, in this case, the second switch module 40 needs to be controlled to be turned on based on a command representing the discharge of the accumulator.

[0051] (3) After the self-heating of the battery 70 is completed using the energy conversion device according to the embodiment of the present application, the second switch module 40 is not sintered, and the second switch module 40 is controlled to turn on based on a command representing the discharge of the accumulator (after the self-heating of the battery 70 is completed using the energy conversion device according to the embodiment of the present application, energy remains in the first capacitor 50, and energy needs to be discharged from the first capacitor 50 for safety reasons). In this case, since the second switch module 40 is not sintered, its on / off can still be controlled. Also, when the first capacitor 50 needs to discharge energy, the second switch module 40 can communicate with the energy discharge circuit simply by being in the on state. Therefore, in this case, the second switch module 40 needs to be controlled to turn on based on a command representing the discharge of the accumulator.

[0052] (4) After the driving function is realized using the energy conversion device according to the embodiment of the present application, the second switch module 40 is not sintered, and the second switch module 40 is controlled to be turned on based on a command representing the discharge of the accumulator (after the driving function is realized using the energy conversion device according to the embodiment of the present application, energy remains in the second capacitor, and for safety reasons, energy must be discharged from the second capacitor). In this case, since the second switch module 40 is not sintered, its on / off can still be controlled. Also, when the first capacitor 50 needs to discharge energy, the second switch module 40 can communicate with the energy discharge circuit simply by being in the on state. Therefore, in this case, the second switch module 40 needs to be controlled to be turned on based on a command representing the discharge of the accumulator.

[0053] The use of the above technical means has the following beneficial effects.

[0054] (1) The energy release of the first capacitor 50 can be achieved by utilizing the interlocking between the components of the energy conversion device itself, and there is no need to add any additional components, thereby reducing the overall cost of the vehicle.

[0055] (2) When the first switch module 10 turns off the connection between the battery 70 and the motor inverter 20 and the second switch module 40 turns on, the motor inverter 20 controls the first capacitor 50 to release energy. This solves the high voltage safety issue caused by the battery 70 during the energy release period of the first capacitor 50. As can be seen from the topology structure of FIG. 1, during the energy release period, the first switch module 10 is in the off state and the second switch module 40 is in the on state, so the energy of the first capacitor 50 is released through the circulation circuit formed by the motor inverter 20, the motor winding 30, the second switch module 40, and the first capacitor 50. That is, the high voltage energy of the first capacitor 50 is consumed through the energy loss caused by the repeated switching operations of the motor inverter 20, the energy consumption of the motor inverter 20 when it is on, and the heat loss in the motor winding 30, thereby realizing the energy release of the first capacitor 50. Furthermore, since the emission current is not large during the emission process, it is possible to avoid converting the pre-firing of the second switch module 40 due to a software bug or incomplete sintering due to the second switch module 40 itself into the firing of the second switch module 40, thereby avoiding secondary damage to the second switch module 40.

[0056] Fig. 5 is another flowchart of a safety control method for an energy conversion device according to an embodiment of the present application. This flowchart is suitable for performing energy release on the energy conversion device shown in Fig. 2. As shown in Fig. 5, the method includes the following steps S51 to S52.

[0057] In step S51, the first switch module 10 is controlled to be turned off based on a command representing the discharge of the accumulator, thereby turning off the connection between the battery 70 and the second capacitor 80 and the motor inverter 20.

[0058] In step S52, when the second switch module 40 is turned on, the motor inverter 20 is controlled to discharge energy to the first capacitor 50 and the second capacitor 80.

[0059] The case where the second switch module 40 is turned on has been described above, and therefore will not be described here.

[0060] Furthermore, step S52 may include the following steps.

[0061] First, in step S52a, the motor inverter 20 is controlled to discharge energy to the first capacitor 50.

[0062] Next, in step S52b, the motor inverter 20 is controlled so that the first capacitor 50 releases energy to the second capacitor 80.

[0063] For example, first, the upper bridge arm of the motor inverter 20 is controlled to be turned on, so that the second capacitor 80 charges the first capacitor 50. Next, the upper bridge arm of the motor inverter 20 is controlled to be kept off, and the lower bridge arm of the motor inverter 20 is controlled to be alternately turned on and off, thereby discharging energy from the charged first capacitor 50. Energy discharging from the second capacitor 80 is achieved by repeatedly performing the steps of controlling the upper bridge arm of the motor inverter 20 to be turned on, and controlling the upper bridge arm to be kept off, and controlling the lower bridge arm of the motor inverter 20 to be alternately turned on and off, until the voltage of the second capacitor 80 becomes lower than a predetermined voltage (e.g., 60 V or other predetermined value).

[0064] When the motor inverter 20 includes multiple bridge arms, the alternately turning on and off of the lower bridge arms referred to herein refers to the alternately turning on and off of at least one lower bridge arm. By controlling the number of lower bridge arms that are alternately turned on and off, the magnitude of the discharge current can be controlled, and secondary damage to the second switch module 40 during the discharge process can be avoided.

[0065] The time it takes for the second capacitor 80 to charge the first capacitor 50 can be calibrated based on the vehicle model, the capacitance value of the first capacitor 50, and the capacitance value of the second capacitor 80. For example, it may be 250 ms, 100 ms, or some other value.

[0066] In step S52, energy is first released from the first capacitor 50, and then the first capacitor 50 releases energy from the second capacitor 80, thereby preventing the first capacitor 50 from generating an impulse current between the first capacitor 50 and the second capacitor 80 due to an uncontrollable diode in the motor inverter 20, and preventing damage to the second switch module 40 during the release process.

[0067] By using the above technical means, energy release from the second capacitor 80 is also achieved by utilizing the interrelationships between components of the energy conversion device itself, eliminating the need for additional components, thereby reducing the overall cost of the vehicle. Furthermore, the principle of energy release from the second capacitor 80 is similar to that of the first capacitor 50 described above, utilizing the energy loss due to repeated switching operations of the motor inverter 20, the energy consumption of the motor inverter 20 when it is on, and the heat loss in the motor windings 30. Therefore, the release current is not large during the release process, which prevents pre-sintering of the second switch module 40 due to a software bug or incomplete sintering due to the second switch module 40 itself from being converted into firing of the second switch module 40, thereby avoiding secondary damage to the second switch module 40.

[0068] In one embodiment, the step of controlling the motor inverter 20 to discharge energy to the first capacitor 50 described above in step S42 and step S52a may include discharging energy to the first capacitor 50 by controlling an upper bridge arm of the motor inverter 20 to hold it off and controlling a lower bridge arm of the motor inverter 20 to alternately turn on and off.

[0069] This technical solution utilizes the energy loss caused by repeated switching operations of the lower bridge arm of the motor inverter 20, the energy consumption when the lower bridge arm of the motor inverter 20 is in the on state, and the heat loss in the motor winding 30 to dissipate the high-voltage energy in the first capacitor 50, thereby realizing energy discharge from the first capacitor 50. Furthermore, because the discharge current is not large during the discharge process, it is possible to avoid converting the pre-sintering of the second switch module 40 caused by a software bug or incomplete sintering caused by the second switch module 40 itself into the firing of the second switch module 40, thereby avoiding secondary damage to the second switch module 40.

[0070] FIG. 6 is a schematic diagram illustrating the alternating on / off adjustment of the lower bridge arm of the motor inverter 20. As can be seen from the diagram, the alternating on / off adjustment of the lower bridge arm involves first controlling the duty ratio of the lower bridge arm to gradually increase from a first duty ratio to a second duty ratio (i.e., the time the lower bridge arm is on / (the time the lower bridge arm is on+the time the lower bridge arm is off) within the same cycle), and then controlling the duty ratio of the lower bridge arm to gradually decrease from the second duty ratio to the first duty ratio. The present application does not limit the specific values ​​of the first and second duty ratios, as long as they continuously cycle through different duty ratios. For example, the first duty ratio may be 20% or another value, and the second duty ratio may be 80%. The present application also does not limit the rate at which the duty ratio increases from the first duty ratio to the second duty ratio or the rate at which the duty ratio decreases from the second duty ratio to the first duty ratio.

[0071] The continuous cycling of the first duty ratio and the second duty ratio achieves the purpose of dissipating the remaining energy in the first capacitor 50 and the second capacitor 80. Furthermore, this discharging method allows the energy in the first capacitor 50 and the second capacitor 80 to be completely discharged within a time period that meets the requirements of the national standard.

[0072] The present application further provides a method for determining whether the second switch module 40 is sintered.

[0073] The first method for determining whether the second switch module 40 is sintered includes the following steps: First, control the motor inverter 20 to perform self-detection. If the self-detection of the motor inverter 20 is normal, control the second switch module 40 to be turned off and control the first switch module 10 to connect the battery 70 to the motor inverter 20. Next, control all lower bridge arms of the motor inverter 20 to be turned off and at least one upper bridge arm of the motor inverter 20 to be turned on. Then, determine whether current flows through the motor inverter 20. If current flows through the motor inverter 20, determine that the second switch module 40 is sintered. If no current flows, determine that the second switch module 40 is not sintered. The motor inverter 20 can use a current sensor that detects the phase current of the existing motor inverter to detect whether current flows through the motor inverter 20, eliminating the need for additional components and reducing costs.

[0074] The second method for determining whether the second switch module 40 is sintered includes the following steps: First, control the motor inverter 20 to self-detect. If the self-detection of the motor inverter 20 is normal, control the second switch module 40 to be turned on and control the first switch module 10 to connect the battery 70 to the motor inverter 20. Next, control the lower bridge arm of the motor inverter 20 to be turned off and at least one upper bridge arm of the motor inverter 20 to be turned on, thereby charging the second capacitor 80 with the battery 70. Then, control the second switch module 40 to be turned off, control the upper bridge arm of the motor inverter 20 to be turned off, and control at least one lower bridge arm of the motor inverter 20 to be turned on. Then, determine whether current flows through the motor inverter 20. If current flows through the motor inverter 20, determine that the second switch module 40 is sintered. If no current flows, determine that the second switch module 40 is not sintered. In the motor inverter 20, a current sensor that detects the phase current of the existing motor inverter can be used to detect whether or not current flows through the motor inverter 20, eliminating the need to add any additional components and reducing costs.

[0075] The advantage of the first determination method is that the control method is simple, and the advantage of the second determination method is that the current is controllable, which can avoid secondary damage to the second switch module 40 during the sintering detection process.

[0076] Although the preferred embodiments of the present application have been described in detail above with reference to the drawings, the present application is not limited to the specific contents of the above embodiments, and various simple modifications can be made to the technical means of the present application within the scope of the technical idea of ​​the present application, and all of these simple modifications fall within the scope of protection of the present application.

[0077] It should be noted that the specific technical features described in the above specific embodiments can be combined in any suitable manner if not contradictory, and in order to avoid unnecessary duplication, this application does not separately describe all possible combinations.

[0078] Furthermore, the various embodiments of the present application can be combined in any manner, and should be considered as being the same as the contents disclosed in the present application, unless they deviate from the spirit of the present application.

Claims

1. a first switch module; a motor inverter having a first bus terminal connected to a first terminal of a battery and a second bus terminal connected to a second terminal of the battery, wherein the first switch module controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery, or controls on / off between the second bus terminal of the motor inverter and the second terminal of the battery, or controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery and on / off between the second bus terminal of the motor inverter and the second terminal of the battery; a motor winding having a first terminal connected to a midpoint terminal of the motor inverter; a second switch module and a first capacitor connected in series, the first terminal of the second switch module and the first capacitor connected in series to the second terminal of the motor winding and the second terminal of the second switch module and the first capacitor connected to the second bus terminal of the motor inverter; a controller configured to control the first switch module to turn off based on a command representing the discharge of an accumulator, thereby disconnecting the battery from the motor inverter, and to control the motor inverter when the second switch module turns on, thereby discharging energy to the first capacitor; When the second switch module is turned on, sintering the second switch module; After the controller has completed charging the battery using an energy conversion device, the second switch module is controlled to be unsintered and to be turned on based on a command representing the discharge of the accumulator; After completing self-heating of the battery using the energy conversion device, controlling the second switch module so that the second switch module is not sintered and turns on based on a command representing discharging the accumulator; and controlling the second switch module to be turned on based on a command representing the discharge of the accumulator, after the energy conversion device is utilized to realize a driving function, so that the second switch module is not sintered.

2. a second capacitor having a first terminal connected to a first bus terminal of the motor inverter and a second terminal connected to a second bus terminal of the motor inverter; 2. The device of claim 1, wherein the controller is further configured to: control the first switch module to turn off based on a command representing the discharge of the accumulator, thereby disconnecting the battery from the second capacitor and the motor inverter; and when the second switch module is turned on, control the motor inverter to discharge energy to the first capacitor and the second capacitor.

3. A safety control method for an energy conversion device, the energy conversion device comprising: a first switch module; a motor inverter having a first bus terminal connected to a first terminal of a battery and a second bus terminal connected to a second terminal of the battery, wherein the first switch module controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery, or controls on / off between the second bus terminal of the motor inverter and the second terminal of the battery, or controls on / off between the first bus terminal of the motor inverter and the first terminal of the battery and on / off between the second bus terminal of the motor inverter and the second terminal of the battery; a motor winding having a first terminal connected to a midpoint terminal of the motor inverter; a second switch module and a first capacitor connected in series, the first terminal of the second switch module being connected to the second terminal of the motor winding after being connected in series, and the second terminal of the second switch module being connected to the second bus terminal of the motor inverter; The method includes controlling the first switch module to turn off based on a command representing the discharge of an accumulator, thereby disconnecting the battery from the motor inverter, and controlling the motor inverter to discharge energy to the first capacitor when the second switch module turns on; When the second switch module is turned on, sintering the second switch module; After completing charging of the battery using the energy conversion device, controlling the second switch module so that the second switch module is not sintered and is turned on based on a command representing the discharge of the accumulator; After completing self-heating of the battery using the energy conversion device, controlling the second switch module so that the second switch module is not sintered and turns on based on a command representing discharging the accumulator; and controlling the second switch module to be turned on based on a command representing the discharge of the accumulator, after the driving function is realized using the energy conversion device, so that the second switch module is not sintered.

4. the energy conversion device further includes a second capacitor having a first terminal connected to a first bus terminal of the motor inverter and a second terminal connected to a second bus terminal of the motor inverter; 4. The safety control method for an energy conversion device according to claim 3, further comprising the steps of: controlling the first switch module to be turned off based on a command representing the discharge of the accumulator, thereby disconnecting the battery from the second capacitor and the motor inverter; and controlling the motor inverter when the second switch module is turned on, thereby discharging energy from the first capacitor and the second capacitor.

5. sintering the second switch module by controlling the second switch module to be off and controlling the first switch module to connect the battery to the motor inverter; Controlling a lower bridge arm of the motor inverter to turn off and controlling at least one upper bridge arm of the motor inverter to turn on; The safety control method for an energy conversion device according to claim 3, characterized in that, when a current flows through the motor inverter, it is determined that the second switch module is sintered.

6. sintering the second switch module by controlling the second switch module to turn on and the first switch module to connect the battery to the motor inverter; Charging the second capacitor with the battery by controlling a lower bridge arm of the motor inverter to be turned off and controlling at least one upper bridge arm of the motor inverter to be turned on; controlling the second switch module to be turned off, controlling an upper bridge arm of the motor inverter to be turned off, and controlling at least one lower bridge arm of the motor inverter to be turned on; The safety control method for an energy conversion device according to claim 4, characterized in that, when a current flows through the motor inverter, it is determined that the second switch module is sintered.

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