Method and apparatus for controlling a power converter and power conversion system

Abstract

Embodiments of the present disclosure provide a method and apparatus for controlling a power converter, a power conversion system, and a fuel cell vehicle. The method comprises: obtaining voltages of a first side and a second side of the power converter after the power converter is powered off, the power converter comprising at least one switching bridge arm; in response to the voltage of the second side being greater than the voltage of the first side and a voltage difference between the voltage of the second side and the voltage of the first side being higher than a threshold, controlling the at least one switching bridge arm to perform a step-down power conversion from the second side to the first side; and in response to the voltage difference between the voltage of the second side after the step-down power conversion and the voltage of the first side not being higher than the threshold, controlling the at least one switching bridge arm to dissipate residual electrical energy stored by energy storage components of the first side and the second side through switching operations of at least one controllable switch in the at least one switching bridge arm. Embodiments of the present disclosure achieve efficient discharge of the power converter and its peripheral circuit at low cost.

Description

Technical Field

[0001] This disclosure relates to the field of power electronics technology, and more specifically, to methods and apparatus for controlling power converters, power conversion systems, and fuel cell vehicles including the power conversion systems. Background Technology

[0002] Power converters or power conversion circuits can achieve desired power conversion operations by controlling the switching of power electronic devices, enabling the transfer and use of electrical energy between different devices and systems. For example, a DC-DC power converter can convert the input DC voltage into the DC voltage required by the load. Power converters or power conversion circuits are widely used in various fields; for example, the power transfer unit (PTU) of a fuel cell vehicle includes a power converter to convert the voltage and / or current output from the fuel cell into the appropriate voltage and / or current to supply downstream equipment.

[0003] Power converters and their peripheral circuits typically include energy storage components such as capacitors, which retain electrical energy even after the system is powered off or disconnected. To prevent residual energy from jeopardizing personnel and equipment, a discharge operation is usually required to dissipate the remaining energy. For example, according to safety requirements for new energy vehicles, fuel cell vehicles' power transfer units (PTUs) need to have active discharge capabilities and must discharge the voltage of high-voltage components to below a specified level within a specified time. However, current active discharge solutions suffer from problems such as low discharge efficiency and high cost. Summary of the Invention

[0004] To at least partially address the above and other potential problems, embodiments of this disclosure provide methods and apparatus for controlling power converters, power conversion systems, and fuel cell vehicles.

[0005] According to a first aspect of this disclosure, a method for controlling a power converter is provided. The method includes: acquiring voltages on a first side and a second side of the power converter after power de-energization, the power converter including at least one switching arm and configured to perform DC power conversion between the first side and the second side; controlling the at least one switching arm to perform a buck power conversion from the second side to the first side in response to a voltage on the second side being greater than a voltage on the first side and a voltage difference between the voltages on the second side and the first side being higher than a threshold; and controlling the at least one switching arm to dissipate remaining electrical energy stored in energy storage components on the first and second sides through switching operations of at least one controllable switch in the at least one switching arm in response to a voltage difference between the voltage on the second side and the voltage on the first side after the buck power conversion not being higher than the threshold.

[0006] According to a second aspect of this disclosure, an apparatus for controlling a power converter is provided, the apparatus comprising: an acquisition unit configured to acquire voltages on a first side and a second side of the power converter after power de-energization, the power converter including at least one switching arm and configured to perform DC power conversion between the first side and the second side; a first control unit configured to control at least one switching arm to perform a buck power conversion from the second side to the first side in response to a voltage on the second side being greater than a voltage on the first side and a voltage difference between the voltage on the second side and the voltage on the first side being higher than a threshold; and a second control unit configured to control at least one switching arm to dissipate residual electrical energy stored in energy storage components on the first side and the second side through switching operation of at least one controllable switch in the at least one switching arm in response to a voltage difference between the voltage on the second side and the voltage on the first side after buck power conversion not being higher than a threshold.

[0007] According to a third aspect of this disclosure, a computer program product is provided, which is tangibly stored on a non-volatile computer-readable medium and includes machine-executable instructions that, when executed, cause a machine to perform the steps of the method according to the first aspect.

[0008] According to a fourth aspect of this disclosure, a power conversion system is provided, the power conversion system comprising: a power converter; and a control device coupled to the power converter and configured to perform the steps of the method according to the first aspect, wherein the energy storage component includes a capacitive component.

[0009] According to a fifth aspect of this disclosure, a fuel cell vehicle is provided, comprising: a fuel cell; and a power conversion system according to a fourth aspect, coupled to the fuel cell, wherein an energy storage component further comprises the fuel cell.

[0010] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify key or principal features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description

[0011] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0012] Figure 1 A schematic circuit diagram of a power conversion device is shown.

[0013] Figure 2 A schematic circuit diagram of a fuel cell vehicle according to an embodiment of the present disclosure is shown.

[0014] Figure 3 A schematic flowchart of a method for controlling a power converter according to an embodiment of the present disclosure is shown.

[0015] Figure 4 A schematic circuit diagram of a power conversion system according to an embodiment of the present disclosure is shown.

[0016] Figure 5 A schematic waveform diagram of the voltages on the first and second sides of a power converter and the control signal of a controllable switch according to an embodiment of the present disclosure is shown.

[0017] Figure 6 A schematic circuit diagram of a portion of the circuitry of a power converter according to an embodiment of the present disclosure is shown.

[0018] Figure 7 A schematic circuit diagram of a power conversion system according to an embodiment of the present disclosure is shown.

[0019] Figure 8A and Figure 8B A schematic waveform diagram of the voltages on the first and second sides of a power converter and the control signal of a controllable switch is shown in an embodiment of the present disclosure when the voltage on the second side is higher than the voltage on the first side.

[0020] Figure 9A and Figure 9B A schematic waveform diagram of the voltages on the first and second sides of a power converter and the control signal of a controllable switch is shown in an embodiment of the present disclosure when the voltage on the first side is higher than the voltage on the second side.

[0021] Figure 10 A schematic circuit diagram of a portion of the circuitry of a power converter according to an embodiment of the present disclosure is shown.

[0022] Figure 11 A schematic block diagram of an apparatus for controlling a power converter according to an embodiment of the present disclosure is shown. Detailed Implementation

[0023] Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. Those skilled in the art can derive alternative technical solutions from the following description without departing from the spirit and scope of the present disclosure.

[0024] The term “comprising” and its variations as used herein signify open inclusion, i.e., “including but not limited to”. Unless otherwise stated, the term “or” means “and / or”. The term “based on” means “at least partially based on”. The term “an embodiment” means “at least one example embodiment”. Other explicit and implicit definitions may also be included below.

[0025] As mentioned earlier, to ensure the safety of personnel and equipment, power conversion devices such as PTUs need to have active discharge capabilities, enabling the voltage of high-voltage components to drop below a specified level within a short period of time. However, current active discharge solutions have several problems. For example, some solutions require additional discharge components to perform the discharge operation, which increases costs and requires additional space.

[0026] Figure 1 A schematic circuit diagram of the power conversion device 100' is shown. Figure 1 As shown, the power conversion device 100' includes a power converter 110', an input capacitor 120', and an output capacitor 130'. As an example, the power converter 110' is a boost circuit and performs DC-DC boost power conversion from the input capacitor 120' side to the output capacitor 130' side. The power conversion device 100' also includes a discharge circuit 150', which includes a switch and a discharge resistor connected in series. After the power conversion device 100' is powered off or de-energized, the switch in the discharge circuit 150' can be turned on to dissipate any remaining electrical energy in the input capacitor 120' and the output capacitor 130' using the discharge resistor.

[0027] exist Figure 1 The power conversion device 100' shown requires an additional discharge circuit 150' and corresponding control components to perform the discharge operation, which increases the overall cost. Furthermore, to dissipate a large amount of electrical energy, the discharge resistor is typically large, requiring the discharge circuit 150' to occupy a significant amount of space. Considering the temperature characteristics of the discharge resistor, the operating frequency of the discharge circuit 150' cannot be too high to ensure sufficient cooling time after discharge, limiting the application scenarios of the discharge circuit 150' and the power conversion device 100'. If an additional cooling circuit is added to dissipate heat from the discharge resistor to increase the operating frequency, it further increases cost and space requirements. Moreover, in some power conversion topologies such as buck-boost converters, it is even necessary to have separate discharge circuits 150' on both the input and output sides to release the electrical energy on both sides, which not only increases cost and space requirements but also complicates the circuit structure and control.

[0028] In addition, in some discharge schemes, the input and output sides of the power converter need to be discharged sequentially, which results in long discharge times and low efficiency, failing to meet the discharge duration requirements in some specifications. For example, the electric vehicle safety guidelines require all high-voltage components of fuel cell vehicles to drop below 60V within 5 seconds.

[0029] This disclosure presents an improved active discharge scheme for a power converter. In this improved scheme, a controllable switch within the power converter is used to step down the voltage on the input and output sides of the power converter, reducing the voltage difference between the two sides to a smaller or essentially the same level. After the step-down adjustment is complete, the remaining electrical energy on both sides of the power converter is dissipated by switching the controllable switch within the power converter. This method allows for discharge using the power converter's own power switching devices without the need for additional discharge circuits or components, avoiding increased costs and space requirements. Furthermore, it allows for higher frequency discharge operations compared to additional discharge resistors. In addition, since the voltages on both sides are adjusted to essentially the same level, the energy storage components on both the input and output sides of the power converter can be discharged simultaneously. This shortens the time required for all high-voltage components in the system to discharge to a lower safe voltage level, improving discharge efficiency.

[0030] Figure 2 A schematic circuit diagram of a fuel cell vehicle 10 according to an embodiment of the present disclosure is shown. Figure 2As shown, the fuel cell vehicle 10 includes a power conversion system 100, a fuel cell 200, and a downstream device 300. The power conversion system 100 is coupled to the fuel cell 200 and the downstream device 300. The power conversion system 100 converts the voltage and / or current output from the fuel cell 200 into the voltage and / or current required by the downstream device 300 and provides it to the downstream device 300. The power conversion system 100 may include a power converter 110, a capacitive component 120, and a capacitive component 130. The power converter 110 may include at least one switching arm and performs DC power conversion between a first side P1 and a second side P2. The power converter 110 may be any type of DC power converter, such as a boost converter, a buck converter, a buck-boost converter, or other types of power converters, or a combination of multiple types of converters. Capacitive components 120 and 130 are respectively disposed on the first side P1 and the second side P2 of the power converter 110 to provide voltage regulation and filtering functions on the first side P1 and the second side P2 of the power converter 110. The power conversion system 100 and its power converter 110 may also include other suitable components required to achieve power conversion operation, such as inductors. As an example, the fuel cell 200 may utilize hydrogen and oxygen as reactants to generate electricity and may consist of multiple fuel cell units. As an example, the downstream equipment 300 may include the energy storage battery pack and / or drive motor of the fuel cell vehicle 10 to receive and / or consume the electrical power provided by the fuel cell 100 via the power conversion system 200. It is understood that, although... Figure 2 The example shows a power conversion system 100 included in a fuel cell vehicle 10, but the use of the power conversion system 100 is not limited to this and can be used in any other scenario that requires power conversion operations.

[0031] exist Figure 2 In the example shown, the first side P1 is arranged as the input side of the power converter 110, and the second side P2 is arranged as the output side of the power converter 110. However, it is understood that by adjusting the connection of the power converter 110 and the capacitive components 120, 130 relative to the fuel cell 200 and the downstream device 300, the second side P2 can also be arranged as the input side of the power converter 110, and the first side P1 as the output side of the power converter 110. Therefore, in the embodiments of this disclosure, the first side P1 and the second side P2 can be the input side and the output side, respectively, or they can be the output side and the input side, respectively; this disclosure does not limit this.

[0032] The power conversion system 100 also includes a control device 140 coupled to the power converter 110. As an example, the control device 140 can acquire electrical measurements related to power conversion operation, such as voltage and / or current on the input and output sides. Thus, the control device 140 can control at least one switching arm in the power converter 110 based on these electrical measurements to output a desired voltage and / or current. After the power conversion system 100 is powered down or de-energized, the control device 140 can control at least one switching arm in the power converter 110 to perform an active discharge operation, dissipating residual electrical energy in energy storage components (e.g., capacitive components 120 and 130 and fuel cell 200) in the vehicle or system within a short time, thereby rapidly reducing the voltage of high-voltage components to a safe level.

[0033] Figure 3 A schematic flowchart of a method 3000 for controlling a power converter 110 according to an embodiment of the present disclosure is shown. Method 3000 can be performed in... Figure 2 This is implemented in the scenario described above and executed by the control device 140. For the purposes of discussion, reference will be made to... Figure 2 To describe method 3000.

[0034] At block 3001, control device 140 acquires the voltage U1 on the first side P1 and the voltage U2 on the second side P2 after the power converter 110 is powered off. As an example, after the fuel cell vehicle 10 is shut down and / or the fuel cell 200 is powered off, the power converter 110 is powered off and the remaining electrical energy in the vehicle system needs to be actively discharged to eliminate safety hazards. Control device 140 can directly acquire the voltage U1 on the first side P1 and the voltage U2 on the second side P2 from associated sensing devices, and / or can indirectly determine the voltages U1 and U2 based on the electrical quantities sensed by the associated sensing devices.

[0035] At block 3002, control device 140 determines whether the absolute value of the difference between voltage U1 and voltage U2 is higher than a predetermined threshold. Specifically, control device 140 can determine the difference between the two based on the acquired voltages U1 and U2, and the predetermined threshold used for the determination can be a relatively small value. Thus, when the difference between voltage U1 and U2 is not higher than the predetermined threshold, it indicates that the voltages of the first side P1 and the second side P2 are basically the same, while when the difference between voltage U1 and U2 is not higher than the predetermined threshold, it indicates that there is a large difference between the voltages of the first side P1 and the second side P2. A large voltage difference will cause undesirable current and power flow between the first side P1 and the second side P2 in the subsequent active discharge stage, causing the electrical energy on the high-voltage side to flow to the low-voltage side without entering the discharge circuit for dissipation, and even causing uncontrollable oscillating current in the inductor, thereby seriously affecting the discharge efficiency and discharge effect. If the absolute value of the difference between voltage U1 and voltage U2 is higher than the predetermined threshold, method 3000 will proceed to block 3003; otherwise, it will proceed to block 3008.

[0036] At block 3003, in response to the absolute value of the difference between voltage U1 and voltage U2 being higher than a predetermined threshold, control device 140 determines whether voltage U2 is greater than voltage U1. Specifically, control device 140 may further determine the voltage relationship between the first side P1 and the second side P2 when the voltage difference is large, to determine which side has a higher voltage. The order between blocks 3002 and 3003 is merely exemplary and not limiting. In some cases, block 3003 may be executed first, followed by block 3002, or both blocks 3002 and 3003 may be executed simultaneously; this disclosure does not limit this. If voltage U2 is greater than voltage U1, method 3000 proceeds to block 3004, and if voltage U1 is greater than voltage U2, method 3000 proceeds to block 3006.

[0037] At block 3004, in response to voltage U2 being greater than voltage U1, control device 140 controls at least one switching arm in power converter 110 to perform a buck power conversion from the second side P2 to the first side P1. For example, if power converter 110 performs a boost conversion from the first side P1 to the second side P2 as a boost converter during normal operation without power-off, the voltage U2 on the second side P2 after power converter 110 is de-energized will typically be greater than the voltage on the first side P1. Therefore, in order to adjust the voltages on both sides to substantially the same voltage level, control device 140 can control the on / off state of at least one switching arm to perform a buck conversion from the second side P2 to the first side P1.

[0038] At box 3005, control device 140 determines whether the voltage difference between the voltage U2 and the voltage U1 after the step-down power conversion is not higher than a predetermined threshold. Specifically, control device 140 can determine during the step-down operation whether the voltage difference between the two has been reduced to a lower level below the predetermined threshold.

[0039] At block 3006, in response to voltage U1 being greater than voltage U2, control device 140 controls at least one switching arm in power converter 110 to perform a step-down power conversion from the first side P1 to the second side P2. At block 3007, control device 140 determines whether the voltage difference between the step-down power converted voltage U1 and voltage U2 is not higher than a predetermined threshold. Specifically, similar to blocks 3004 and 3005, if voltage U1 on the first side P1 is greater than voltage U2 on the second side P2, then after power-off, control device 140 controls at least one switching arm to perform a step-down operation from the first side P1 to the second side P2 to reduce the voltage difference between voltage U1 and voltage U2 to a lower level below the predetermined threshold.

[0040] At block 3008, in response to the voltage difference between voltage U2 and voltage U1, or the voltage difference between voltage U1 and voltage U2 not exceeding a predetermined threshold, control device 140 controls at least one switching arm in power converter 110 to dissipate the remaining electrical energy stored in the energy storage components of the first side P1 and the second side P2 through the switching operation of at least one controllable switch in at least one switching arm. Specifically, when the voltages on both sides of power converter 110 are substantially the same or have a small difference, control device 140 can control at least one arm to perform an active discharge operation, so that all the remaining electrical energy in the energy storage components on both sides is dissipated through switching losses during the switching operation of the controllable switch. In this way, the increased cost and space occupation caused by additional discharge components are avoided, and since the switching devices in the power converter are usually equipped with corresponding heat dissipation devices, the discharge operation can be performed at a relatively higher frequency. In addition, since the voltage difference on both sides of the power converter is small or substantially the same, the discharge of the energy storage components on the first side and the second side can be synchronized, thereby ensuring that the high voltage components on both sides can be reduced to a safe level in a shorter time, improving discharge efficiency. In one embodiment, the energy storage component to be discharged includes a capacitive component 120 located on a first side P1 and a capacitive component 130 located on a second side P2. Residual electrical energy in the capacitive components 120 and 130 of the power conversion system 100 can be released and dissipated through a discharge operation. In one embodiment, the energy storage component to be discharged also includes a fuel cell 200. Since the fuel cell 200 needs to be de-energized to a safe level quickly, in addition to the capacitive components 120 and 130, an active discharge operation can be performed on the fuel cell 200 to facilitate a rapid decrease in its voltage. It is understood that the energy storage component that releases electrical energy through a discharge operation is not limited to this and may include other components or elements in and on both sides of the power converter that store electrical energy and need to be discharged.

[0041] In some embodiments of this disclosure, the control device 140 controls at least one controllable switch in at least one switch bridge arm to alternately switch between an on state and an off state. The at least one controllable switch includes a controllable switch located in the lower arm of the at least one switch bridge arm. Specifically, through the controllable switch in the lower arm, a discharge circuit can be formed for both energy storage components, thereby simultaneously discharging the energy storage components on both sides using the switching operation of the controllable switch in the same lower arm. Furthermore, when dissipating electrical energy using the controllable switch, the controllable switch can be controlled to alternately switch between an on state and an off state. This allows the controllable switch to generate sufficient switching losses to dissipate electrical energy while preventing the controllable switch from being damaged by excessive discharge current over a prolonged period. In one embodiment, the control device 140 generates a pulse width modulation (PWM) signal for the at least one controllable switch. Specifically, a PWM control method can be used to control the controllable switch, thereby providing a control signal that alternates between an on state and an off state.

[0042] In some embodiments of this disclosure, in response to the voltage difference between the buck-converted voltage U2 and the voltage U1, or the voltage difference between the voltage U1 and the voltage U2 not exceeding a predetermined threshold, the control device 140 increases the drive resistance of at least one controllable switch, the drive resistance being coupled to the control terminal of the at least one controllable switch. Specifically, after the voltage adjustment on both sides is completed, before or during discharge, the drive resistance coupled to the controllable switch used for dissipating electrical energy can be increased, thereby enabling faster dissipation of electrical energy during discharge by utilizing a larger drive resistance, thus improving discharge efficiency.

[0043] Figure 4 A schematic circuit diagram of a power conversion system 100A according to an embodiment of the present disclosure is shown. Figure 4As shown, the power conversion system 100A includes a power converter 110A and capacitive components 120 and 130 located on a first side P1 and a second side P2, respectively. The power converter 110A includes a switch arm 111 and an inductor 113. The switch arm 111 includes a controllable switch SW1 and an anti-parallel diode D1 on the upper arm, and also includes a controllable switch SW2 and an anti-parallel diode D2 on the lower arm. For example, the controllable switches SW1 and SW2 can be N-type MOSFETs or other types of power switching devices. When power is converted and flows from the first side P1 to the second side P2, the power converter 110A is a boost power converter, and when power is converted and flows from the second side P2 to the first side P1, the power converter 110A is a buck power converter. When the power converter 110A is a boost power converter, the controllable switch SW1 of the upper arm can be in a state of being off or uncontrolled, while only the controllable switch SW2 of the lower arm is controlled (e.g., PWM control) to achieve boost conversion from the first side P1 to the second side P2. When the power converter 110A is a buck power converter, the controllable switch SW2 of the lower arm can be in a state of being off or uncontrolled, while only the controllable switch SW1 of the upper arm is controlled (e.g., PWM control) to achieve buck conversion from the second side P2 to the first side P1.

[0044] For example, when the vehicle 10 is turned off or the fuel cell 200 is powered down, the power conversion system 100A or power converter 110A is de-energized and active discharge of high-voltage components is required. The control device 140 can appropriately control the switch arm 111 to achieve the required active discharge. When active discharge is required, the control device 140 can acquire the voltage U1 of the first side P1 and the voltage U2 of the second side, and generate control signals G1 and G2 based on voltages U1 and U2 to control the controllable switches SW1 and SW2, respectively.

[0045] Figure 5 Schematic waveforms of voltages U1 and U2 on the first side P1 and the second side P2 of a power conversion system 100A according to an embodiment of the present disclosure, and control signals G1 and G2 of controllable switches SW1 and SW2, are shown. Figure 5The diagram illustrates the discharge-related operation process after a power failure of the power conversion system 100A. During normal operation without power failure, the power converter 110A functions as either a boost converter from the first side P1 to the second side P2 or a buck converter from the second side P2 to the first side P1. Therefore, after a power failure of the power conversion system 100A, the voltage U2 on the second side P2 is typically still higher than the voltage U1 on the first side P1. After the control device 140 determines that voltage U2 is higher than voltage U1 and the voltage difference is higher than a predetermined threshold, the control device 140 initiates the discharge-related operation process, which may include time periods S1, S2, and S3.

[0046] During time period S1, control device 140 controls controllable switch SW1 to alternately switch between an on and off state, and controls controllable switch SW2 to be in the off state. As an example, control device 140 sends a signal G1 (e.g., a PWM signal) that alternates between high and low levels to the control terminal of controllable switch SW1, and sends a continuous off signal G2 (e.g., a low-level signal) to the control terminal of controllable switch SW2. In this way, power converter 110A operates as a buck converter during time period S1, transferring electrical energy from the second side P2, which has a higher voltage, to the first side P1. Consequently, the voltage U2 of the second side P2 gradually decreases, while the voltage U1 of the first side P1 gradually increases. At the end of time period S1, voltages U2 and U1 reach a state where they are substantially the same or only slightly different.

[0047] During time period S2, control device 140 controls controllable switch SW1 to be on and controllable switch SW2 to be off. During this time period, the buck conversion operation stops, and the voltages on the first side P1 and the second side P2 are basically the same or have a small difference, so there is no current or power flow between the two sides of power converter 110A. Time period S2 exists as a transition phase after the buck operation and can be omitted in some cases.

[0048] During time period S3, control device 140 controls controllable switch SW1 to be in the ON state and controls controllable switch SW2 to alternately switch between the ON and OFF states. As an example, control device 140 sends a signal G2 (e.g., a PWM signal) that alternates between high and low levels to the control terminal of controllable switch SW2, and sends a continuous ON signal G1 (e.g., a high-level signal) to the control terminal of controllable switch SW1. Thus, power converter 110A begins to perform active discharge operation. The current formed by the residual energy of capacitive component 120 returns from the positive plate of capacitive component 120 through inductor 113 and the controllable switch SW2 that alternates between ON and OFF to the negative plate of capacitive component 120, and the residual energy is dissipated as switching losses of controllable switch SW2. The residual electrical energy in capacitive component 130 forms a current that flows from the positive plate of capacitive component 130 back to the negative plate of capacitive component 130 via a switched-on controllable switch SW1 and a controllable switch SW2 that alternately switches on and off, with the residual electrical energy dissipated as a switching loss of controllable switch SW2. It is understood that if it is necessary to discharge fuel cell 200 or other energy storage components (e.g., fuel cell 200) on the first side P1 and the second side P2, the discharge can be accomplished in a manner similar to that of capacitive components 120 and 130. Through operation during time periods S1, S2, and S3, the voltage of capacitive components 120 and 130, as well as other high-voltage components, can drop to a safe level below 60V within a short time (e.g., 5 seconds).

[0049] Figure 6 A schematic circuit diagram of a portion of the circuitry of a power converter 110A according to an embodiment of the present disclosure is shown. After time period S1, for example during time period S2 which serves as a transition phase, the voltage difference between the voltage U2 on the second side P2 after buck power conversion and the voltage U1 on the first side P1 is not higher than a threshold (i.e., voltages U2 and U1 are substantially the same or have a small difference), thereby allowing the control device 140 to increase the drive resistance of the controllable switch SW2. For example, as... Figure 6As shown, the power converter 110A includes a drive resistor assembly 116 coupled to the control terminal (e.g., the gate of an N-type MOSFET) of a controllable switch SW2 on a switch bridge arm 111. The drive resistor assembly 116 may include a resistor RD1, a resistor RD2 connected in parallel with the resistor RD1, and a switch SW5 connected in series with each other. During normal operation of the power converter 110A without power interruption and during the time period S1 of the discharge-related operation process, the control device 140 may close the switch SW5 to connect the resistors RD1 and RD2 in parallel, and the drive resistance of the controllable switch SW2 is the parallel resistance of the resistors RD1 and RD2. Further, during the time period S2 of the discharge-related operation process, the control device 140 may open the switch SW5, whereby the drive resistance of the controllable switch SW2 consists only of the resistor RD1, which is greater than the parallel resistance of the resistors RD1 and RD2. In this way, the controllable switch SW2 can be driven with a larger drive resistor during the discharge operation period S3. This higher drive resistor slows down the switching process of the switching transistor, thereby increasing switching losses to dissipate more energy. This accelerates energy dissipation and thus speeds up the discharge process. However, it is understood that the drive resistor component 116 can also be other forms, such as an adjustable resistor with a variable resistance.

[0050] Figure 7 A schematic circuit diagram of a power conversion system 100B according to an embodiment of the present disclosure is shown. Figure 7As shown, the power conversion system 100B includes a power converter 110B and capacitive components 120 and 130 located on the first side P1 and the second side P2, respectively. The power converter 110B includes a switch arm 111, a switch arm 112, and an inductor 113. Switch arm 111 includes a controllable switch SW1 and an anti-parallel diode D1 on the upper arm, and a controllable switch SW2 and an anti-parallel diode D2 on the lower arm. Switch arm 112 includes a controllable switch SW3 and an anti-parallel diode D3 on the upper arm, and a controllable switch SW4 and an anti-parallel diode D4 on the lower arm. For example, controllable switches SW1 to SW4 can be N-type MOSFETs or other types of power switching devices. Whether power is converted and flows from the first side P1 to the second side P2 or from the second side P2 to the first side P1, the power converter 110B can operate as a buck-boost power converter. For example, when power is converted and flows from the first side P1 to the second side P2, controllable switches SW1 and SW4 can be switched on and off (e.g., by PWM control), while controllable switches SW2 and SW3 are turned off or complementary on / off control is applied relative to controllable switches SW1 and SW4, thereby achieving a buck-boost conversion from the first side P1 to the second side P2. Similarly, when power is converted and flows from the second side P2 to the first side P1, controllable switches SW2 and SW3 can be switched on and off (e.g., by PWM control), while controllable switches SW1 and SW4 are turned off or complementary on / off control is applied relative to controllable switches SW2 and SW3, thereby achieving a buck-boost conversion from the second side P2 to the first side P1.

[0051] For example, when the vehicle 10 is turned off or the fuel cell 200 is powered down, the power conversion system 100B or power converter 110B is de-energized and active discharge of high-voltage components is required. The control device 140 can appropriately control the switch arms 111 and 112 to achieve the required discharge. When active discharge is required, the control device 140 can acquire the voltage U1 of the first side P1 and the voltage U2 of the second side P2, and generate control signals G1 to G4 based on voltages U1 and U2 to control the controllable switches SW1 to SW4 respectively.

[0052] Figure 8A and Figure 8B A schematic waveform diagram of voltages U1 and U2 on the first side P1 and the second side P2 of the power conversion system 100B, and control signals G1 to G4 of controllable switches SW1 to SW4, is shown when voltage U2 is higher than voltage U1. After the control device 140 determines that voltage U2 is higher than voltage U1 and the voltage difference is higher than a predetermined threshold, the control device 140 initiates an operation process related to active discharge.

[0053] The following is for reference Figure 8A The first operating procedure related to the active discharge of the power conversion system 100B is described when the voltage U2 on the second side P2 is higher than the voltage U1 on the first side P1. The first operating procedure may include time periods S1, S2 and S3.

[0054] During time period S1, control device 140 controls controllable switch SW3 to alternately switch between on and off states, controls controllable switch SW1 to be on, and controls controllable switches SW2 and SW4 to be off. As an example, control device 140 sends a signal G3 (e.g., a PWM signal) that alternates between high and low levels to the control terminal of controllable switch SW3, sends a continuous on signal G1 (e.g., a high-level signal) to the control terminal of controllable switch SW1, and sends continuous off signals G2 and G4 (e.g., low-level signals) to the control terminals of controllable switches SW2 and SW4. In this way, power converter 110A operates as a buck converter during time period S1, transferring electrical energy from the second side P2, which has a higher voltage, to the first side P1. Consequently, the voltage U2 of the second side P2 gradually decreases, while the voltage U1 of the first side P1 gradually increases. At the end of time period S1, voltages U2 and U1 reach a state where they are substantially the same or only slightly different.

[0055] During time period S2, control device 140 controls controllable switches SW1 and SW3 to be in the ON state, and controls controllable switches SW2 and SW4 to be in the OFF state. During this time period, the buck conversion operation stops, and the voltages on the first side P1 and the second side P2 are basically the same or have a small difference, so there is no current or power flow between the two sides of power converter 110A. Time period S2 exists as a transition phase after the buck operation and can be omitted in some cases.

[0056] During time period S3, control device 140 controls controllable switches SW1 and SW3 to be in the ON state, controls controllable switch SW2 to be in the OFF state, and controls controllable switch SW4 to alternate between the ON and OFF states. As an example, control device 140 sends continuous ON signals G1 and G3 (e.g., high-level signals) to the control terminals of controllable switches SW1 and SW3, sends a continuous OFF signal G2 (e.g., low-level signal) to controllable switch SW2, and sends a signal G4 (e.g., a PWM signal) that alternates between high and low levels to the control terminal of controllable switch SW4. Thus, power converter 110B begins to perform active discharge operation. The current formed by the residual energy of capacitive component 120 returns from the positive plate of capacitive component 120 through the ON controllable switch SW1, inductor 113, and the controllable switch SW4 that alternates between ON and OFF to the negative plate of capacitive component 120, and the residual energy is dissipated as switching losses of controllable switch SW4. The residual electrical energy in capacitive component 130 forms a current that flows from the positive plate of capacitive component 130 back to the negative plate of capacitive component 130 via a switched-on controllable switch SW3 and a controllable switch SW4 that alternately switches between on and off. The residual electrical energy is dissipated as a switching loss of controllable switch SW4. It is understood that if it is necessary to discharge fuel cell 200 or other energy storage components on the first side P1 and the second side P2, the discharge can be accomplished in a manner similar to that of capacitive components 120 and 130. Through operation during time periods S1, S2, and S3, the voltage of capacitive components 120 and 130, as well as other high-voltage components, can drop to a safe level below 60V within a short time (e.g., 5 seconds).

[0057] The following is for reference Figure 8B The second operation process related to the discharge of the power conversion system 100B is described when the voltage U2 on the second side P2 is higher than the voltage U1 on the first side P1.

[0058] and Figure 8A The difference is that, Figure 8BA different buck converter scheme is employed during time period S1. Specifically, during time period S1, control device 140 controls controllable switches SW2 and SW3 to alternately switch between on and off states, and controls controllable switches SW1 and SW4 to be in the off state. As an example, control device 140 sends PWM signals G2 and G3 that alternate between high and low levels to the control terminals (e.g., the gates of N-type MOSFETs) of controllable switches SW2 and SW3, and sends continuous off signals G1 and G4 (e.g., low-level signals) to the control terminals (e.g., the gates of N-type MOSFETs) of controllable switches SW1 and SW4. In this way, power converter 110B operates as a buck-boost converter with a voltage conversion ratio of less than 1 during time period S1, transferring electrical energy from the second side P2, which has a higher voltage, to the first side P1. As a result, the voltage U2 of the second side P2 gradually decreases, while the voltage U1 of the first side P1 gradually increases. At the end of time period S1, voltages U2 and U1 reach a state where they are substantially the same or have a small difference. Figure 8B The operations of time periods S2 and S3 and Figure 8A The same applies, so I will not elaborate further.

[0059] Figure 9A and Figure 9B A schematic waveform diagram of the voltages U1 and U2 on the first side P1 and the second side P2 of the power conversion system 100B, and the control signals G1 to G4 of the controllable switches SW1 to SW4, is shown when voltage U1 is higher than voltage U2. After the control device 140 determines that the voltage U1 on the first side P1 is higher than the voltage U2 on the second side P2 and the voltage difference is higher than a predetermined threshold, the control device 140 initiates a discharge-related operation process.

[0060] Figure 9A The operation process and Figure 8A The operation processes correspond accordingly, and due to the different directions of the step-down conversion, the only difference between the two is that the controlled and manageable switch in time period S1 is slightly different. For example... Figure 9A As shown, during time period S1, control device 140 controls controllable switch SW1 to alternately switch between the on and off states, controls controllable switch SW3 to be in the on state, and controls controllable switches SW2 and SW4 to be in the off state. For example, control device 140 sends signal G1 (e.g., a PWM signal) to controllable switch SW1, sends on signal G3 (e.g., a high-level signal) to controllable switch SW3, and sends off signals G2 and G4 (e.g., low-level signals) to controllable switches SW2 and SW4. Thus, power converter 110B operates as a buck converter, and... Figure 9ADuring time period S1, energy from the higher-voltage side P1 is transferred to the lower-voltage side P2. The voltage U1 of the first side P1 gradually decreases, while the voltage U2 of the second side P2 gradually increases. At the end of time period S1, voltages U1 and U2 reach a state where they are basically the same or have a small difference. Figure 9A The operations of time periods S2 and S3 and Figure 8A The same applies, so I will not elaborate further.

[0061] Figure 9B The operation process and Figure 8B The operation processes correspond accordingly, and due to the different directions of the step-down conversion, the only difference between the two is that the controlled and manageable switch in time period S1 is slightly different. For example... Figure 9B As shown, during time period S1, control device 140 controls controllable switches SW1 and SW4 to alternately switch between on and off states, and controls controllable switches SW2 and SW3 to be in the off state. For example, control device 140 sends signals G1 and G4 (e.g., PWM signals) to controllable switches SW1 and SW4, and sends off signals G2 and G3 (e.g., low-level signals) to controllable switches SW2 and SW3. Thus, power converter 110B operates as a buck-boost converter with a voltage conversion ratio of less than 1, and... Figure 9B During time period S1, energy from the higher-voltage side P1 is transferred to the lower-voltage side P2. The voltage U1 of the first side P1 gradually decreases, while the voltage U2 of the second side P2 gradually increases. At the end of time period S1, voltages U1 and U2 reach a state where they are basically the same or have a small difference. Figure 9B The operations of time periods S2 and S3 and Figure 8A and Figure 8B The same applies, so I will not elaborate further.

[0062] exist Figure 8A , Figure 8B , Figure 9A and Figure 9BIn the exemplary operation, discharge is achieved using the switching losses in the switching operation of controllable switch SW4 during time period S3. However, discharge can also be achieved using the switching losses in the switching operation of controllable switch SW2 in another switch arm 111 during time period S3. When discharging using the switching operation of controllable switch SW2, during time period S3, control device 140 controls controllable switch SW2 to alternately switch between the on and off states, controls controllable switch SW4 to be in the off state, and controls controllable switches SW1 and SW3 to be in the on state. For example, control device 140 sends a PWM signal to controllable switch SW2, sends high-level signals to controllable switches SW1 and SW3, and sends a low-level signal to controllable switch SW4. Therefore, the current generated by the residual electrical energy of the capacitive component 120 returns from the positive plate of the capacitive component 120 to the negative plate of the capacitive component 120 via the on-state controllable switch SW1 and the controllable switch SW2, which alternately switches between on and off, and the residual electrical energy is dissipated as a switching loss of the controllable switch SW2. Similarly, the current generated by the residual electrical energy of the capacitive component 130 returns from the positive plate of the capacitive component 130 to the negative plate of the capacitive component 130 via the on-state controllable switch SW3, the inductor 113, and the controllable switch SW2, which alternately switches between on and off, and the residual electrical energy is dissipated as a switching loss of the controllable switch SW2. In one embodiment, during time period S3, the switching operations for discharging can also be performed alternately by the controllable switches SW2 and SW4. For example, during the first time interval of time period S3, a PWM signal is sent to controllable switch SW2 and controllable switch SW4 is turned off, allowing the switching losses of controllable switch SW2 to dissipate energy. Then, during another time interval following the first time interval of time period S3, a PWM signal is sent to controllable switch SW4 and controllable switch SW2 is turned off, allowing the switching losses of controllable switch SW4 to dissipate energy. In this way, the controllable switches of both switching arms can be fully utilized during discharge, avoiding the risk of damage due to overheating of a single controllable switch. Furthermore, this method allows the power converter to withstand and dissipate higher discharge energy during discharge.

[0063] Figure 10 A schematic circuit diagram of a portion of the circuitry of a power converter 110B according to an embodiment of the present disclosure is shown. In the power converter 110B, after time period S1, for example during time period S2, the control device 140 may increase the drive resistance of the controllable switches SW2 and / or SW4. For example, as Figure 10As shown, the power converter 110B includes a drive resistor assembly 116 coupled to the control terminal of a controllable switch SW2 coupled to switch bridge arm 111, and / or a drive resistor assembly 117 coupled to the control terminal of a controllable switch SW4 coupled to switch bridge arm 112. Drive resistor assembly 116 may include resistor RD1 and resistor RD2 connected in parallel with resistor RD1, and switch SW5, with resistor RD2 and switch SW5 connected in series. Drive resistor assembly 117 may include resistor RD3 and resistor RD4 connected in parallel with resistor RD3, and switch SW6, with resistor RD4 and switch SW6 connected in series. During normal operation of the power converter 110B without power interruption and during time period S1 of the operation process related to discharge, control device 140 may close switches SW5 and SW6 to connect resistors RD1 and RD2 in parallel and resistors RD3 and RD4 in parallel. During time period S2, which involves the discharge-related operation, switch SW5 can be disconnected when discharging is performed using the switching operation of controllable switch SW2, and switch SW6 can be disconnected when discharging is performed using the switching operation of controllable switch SW4. In this way, controllable switches SW2 and / or SW4 can be driven with a larger drive resistance during time period S3, thereby slowing down the switching process of the switching transistors and increasing switching losses to dissipate more energy. This accelerates energy dissipation and thus speeds up the discharge process. However, it is understood that drive resistor components 116 and 117 can also be other forms, such as adjustable resistors with variable resistance.

[0064] Figures 4 to 10 An exemplary description is provided of an active discharge process in the case of a power conversion system 100 including a boost converter, a buck converter, and a buck-boost converter. However, it is understood that embodiments of this disclosure can also be implemented in other types of circuit topologies besides boost converters, buck converters, and buck-boost converters, as long as the voltage difference between the two sides can be adjusted and the power can be dissipated by utilizing the switching operation of the switch bridge arm itself.

[0065] Figure 11 A schematic block diagram of an apparatus 1100 for controlling a power converter 110 according to an embodiment of the present disclosure is shown. The apparatus 1100 can be implemented as follows: Figure 2 , Figure 4 and Figure 7 Control device 140. For example... Figure 11As shown, the device 1100 includes an acquisition unit 1110. The acquisition unit 1110 is configured to acquire voltages U1 and U2 of a first side P1 and a second side P2 after the power converter 110 is powered off. The power converter 110 includes at least one switching arm and is configured to perform DC power conversion between the first side P1 and the second side P2. The device 1100 also includes a first control unit 1120. The first control unit 1120 is configured to control at least one switching arm to perform a buck power conversion from the second side P2 to the first side P1 in response to the voltage of the second side P2 being greater than the voltage of the first side P1 and the voltage difference between the voltage of the second side P2 and the voltage of the first side P1 being higher than a predetermined threshold. Furthermore, the device 1100 also includes a second control unit 1130. The third control unit 1130 is configured to control at least one switch arm to dissipate the remaining electrical energy stored in the energy storage components of the first side P1 and the second side P2 through the switching operation of at least one controllable switch in at least one switch arm in response to the voltage difference between the voltage U2 of the second side P2 after buck power conversion and the voltage U1 of the first side P1 not exceeding a predetermined threshold.

[0066] In some embodiments of this disclosure, the second control unit 1130 controls at least one controllable switch to alternately switch between an on state and an off state, the at least one controllable switch including a controllable switch located in the lower arm of at least one switch bridge arm. In one embodiment, the second control unit 1130 generates a pulse width modulation signal for at least one controllable switch.

[0067] Those skilled in the art will understand that the various steps of the methods disclosed above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using device-executable program code, which can then be stored in a storage device for execution by the computing device. Alternatively, they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this disclosure is not limited to any particular combination of hardware and software.

[0068] It should be understood that although several devices or sub-devices of the device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more devices described above can be embodied in one device. Conversely, the features and functions of one device described above can be further divided and embodied by multiple devices.

[0069] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method (3000) for controlling a power converter (110), comprising: (3001) Obtain the voltage of the first side (P1) and the second side (P2) of the power converter (110) after power is turned off, the power converter (110) includes at least one switching bridge arm and is configured to perform DC power conversion between the first side (P1) and the second side (P2); In response to the voltage on the second side (P2) being greater than the voltage on the first side (P1) and the voltage difference between the voltage on the second side (P2) and the voltage on the first side (P1) being higher than a threshold, the at least one switching arm is controlled (3004) to perform a buck power conversion from the second side (P2) to the first side (P1); and In response to the voltage difference between the second side (P2) after buck power conversion and the first side (P1) not exceeding the threshold, the at least one switch arm is controlled (3008) to dissipate the remaining electrical energy stored in the energy storage components (120, 130, 200) of the first side (P1) and the second side (P2) through the switching operation of at least one controllable switch in the at least one switch arm.

2. The method (3000) according to claim 1, wherein controlling (3008) the at least one switch arm to dissipate the remaining electrical energy stored in the energy storage components (120, 130, 200) of the first side (P1) and the second side (P2) through switching operation of at least one controllable switch in the at least one switch arm comprises: The at least one controllable switch is controlled to alternate between an on state and an off state, wherein the at least one controllable switch includes a controllable switch located in the lower arm of the at least one switch bridge arm.

3. The method (3000) according to claim 1, wherein controlling the at least one controllable switch to alternately switch between an on state and an off state comprises: Generate a pulse width modulation signal for the at least one controllable switch.

4. The method (3000) according to claim 2, further comprising: In response to the voltage difference between the second side (P2) after buck power conversion and the first side (P1) not exceeding a threshold, the driving resistance of the at least one controllable switch is increased, and the driving resistance is coupled to the control terminal of the at least one controllable switch.

5. The method (3000) according to claim 1, wherein the power converter (110) comprises a boost converter or a buck converter (110A), and the at least one switch arm comprises a first switch arm (111), the first switch arm (111) comprising a first controllable switch (SW1) and a first anti-parallel diode (D1) located on the upper arm and a second controllable switch (SW2) and a second anti-parallel diode (D2) located on the lower arm. Controlling (3004) at least one switching bridge arm to perform a buck power conversion from the second side (P2) to the first side (P1) includes: Control the first controllable switch (SW1) to alternate between the on and off states; as well as Control the second controllable switch (SW2) to be in the off state.

6. The method (3000) according to claim 5, wherein controlling (3008) the at least one switch arm to dissipate the remaining electrical energy stored in the energy storage components (120, 130, 200) of the first side (P1) and the second side (P2) through switching operation of at least one controllable switch in the at least one switch arm comprises: Control the first controllable switch (SW1) to be in the ON state; as well as Control the second controllable switch (SW2) to alternate between the on and off states.

7. The method (3000) according to claim 5, further comprising: In response to the voltage difference between the second side (P2) after buck power conversion and the first side (P1) not exceeding a threshold, the driving resistance of the second controllable switch (SW2) is increased, and the driving resistance is coupled to the control terminal of the second controllable switch (SW2).

8. The method (3000) according to claim 1, wherein the power converter (110) comprises a buck-boost converter (110B), and the at least one switching arm comprises a first switching arm (111) adjacent to the first side (P1) and a second switching arm (112) adjacent to the second side (P2), the first switching arm (111) comprising a first controllable switch (SW1) and a first anti-parallel diode (D1) located on the upper arm and a second controllable switch (SW2) and a second anti-parallel diode (D2) located on the lower arm, the second switching arm (112) comprising a third controllable switch (SW3) and a third anti-parallel diode (D3) located on the upper arm and a fourth controllable switch (SW4) and a fourth anti-parallel diode (D4) located on the lower arm, Controlling the at least one switch arm to perform a buck power conversion from the second side (P2) to the first side (P1) includes: Control the first controllable switch (SW1) to be in the ON state; Control the second controllable switch (SW2) and the fourth controllable switch (SW4) to be in the off state; as well as The third controllable switch (SW3) is controlled to alternate between the on and off states.

9. The method (3000) according to claim 1, wherein the power converter (110) comprises a buck-boost converter (110B), and the at least one switching arm comprises a first switching arm (111) adjacent to the first side (P1) and a second switching arm (112) adjacent to the second side (P2), the first switching arm (111) comprising a first controllable switch (SW1) and a first anti-parallel diode (D1) located on the upper arm and a second controllable switch (SW2) and a second anti-parallel diode (D2) located on the lower arm, the second switching arm (112) comprising a third controllable switch (SW3) and a third anti-parallel diode (D3) located on the upper arm and a fourth controllable switch (SW4) and a fourth anti-parallel diode (D4) located on the lower arm, Controlling (3004) at least one switching bridge arm to perform a buck power conversion from the second side (P2) to the first side (P1) includes: Control the first controllable switch (SW1) and the fourth controllable switch (SW4) to be in the off state; as well as The second controllable switch (SW2) and the third controllable switch (SW3) are controlled to alternately switch between the on and off states.

10. The method (3000) according to claim 8 or 9, wherein controlling (3008) the at least one switch arm to dissipate the remaining electrical energy stored in the energy storage components (120, 130, 200) of the first side (P1) and the second side (P2) through switching operation of at least one controllable switch in the at least one switch arm comprises: Control the first controllable switch (SW1) and the third controllable switch (SW3) to be in the ON state; as well as Control the second controllable switch (SW2) to be in the off state and control the fourth controllable switch (SW4) to alternate between the on state and the off state, or control the fourth controllable switch (SW4) to be in the off state and control the second controllable switch (SW2) to alternate between the on state and the off state.

11. The method (3000) according to claim 8 or 9, further comprising: In response to the voltage difference between the second side (P2) after buck power conversion and the first side (P1) not exceeding a threshold, the driving resistance of the fourth controllable switch (SW4) or the driving resistance of the second controllable switch (SW2) is increased. The driving resistance of the fourth controllable switch (SW4) is coupled to the control terminal of the fourth controllable switch (SW4), and the driving resistance of the second controllable switch (SW2) is coupled to the control terminal of the second controllable switch (SW2).

12. An apparatus (1100) for controlling a power converter (110), comprising: The acquisition unit (1110) is configured to acquire the voltages of a first side (P1) and a second side (P2) of the power converter (110) after it is powered off. The power converter (110) includes at least one switching arm and is configured to perform DC power conversion between the first side (P1) and the second side (P2). A first control unit (1120) is configured to control the at least one switching arm to perform a buck power conversion from the second side (P2) to the first side (P1) in response to the voltage of the second side (P2) being greater than the voltage of the first side (P1) and the voltage difference between the voltage of the second side (P2) and the voltage of the first side (P1) being higher than a threshold. as well as The second control unit (1130) is configured to control the at least one switch arm to dissipate the remaining electrical energy stored in the energy storage components (120, 130, 200) of the first side (P1) and the second side (P2) through the switching operation of at least one controllable switch in the at least one switch arm in response to the voltage difference between the voltage of the second side (P2) after buck power conversion and the voltage of the first side (P1) not exceeding the threshold.

13. A computer program product tangibly stored on a non-volatile computer-readable medium and comprising machine-executable instructions that, when executed, cause a machine to perform the steps of the method (3000) according to any one of claims 1 to 11.

14. A power conversion system (100), comprising: Power converter (110); as well as A control device (140) is coupled to the power converter (110) and configured to perform the method according to any one of claims 1 to 11, wherein the energy storage components (120, 130, 200) include capacitive components (120, 130).

15. A fuel cell vehicle (10), comprising: Fuel cell (200); as well as The power conversion system (100) according to claim 14 is coupled to the fuel cell (200), wherein the energy storage components (120, 130, 200) further include the fuel cell (200).

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