Power converter and method of controlling a power converter

Abstract

This application discloses a power converter and a control method for the power converter, belonging to the field of power converters. The power converter includes: at least two power conversion circuits; each power conversion circuit has one end connected to the DC bus input side and the other end connected to the output side; each power conversion circuit includes at least one capacitor; a controller is used to control the switching of devices within the power conversion circuits, so that the residual voltage of the capacitor in the power conversion circuits is reduced to a target threshold within a first time period. The power converter of this application can achieve rapid dissipation of the residual capacitor voltage, reduce the impact of the current generated by the residual capacitor voltage on the relays after the series / parallel relays are closed, and extend their service life; while maintaining the energy conversion efficiency of the power converter, it can also improve the start-up speed of the power converter.

Description

Technical Field

[0001] This application belongs to the field of power converters, and particularly relates to a power converter and a control method for the power converter. Background Technology

[0002] DC-DC converters are widely used in new energy systems. One end of the DC-DC converter connects to the high-voltage side DC bus, and the other end connects to the energy storage battery. Internally, a DC-DC converter includes series / parallel relays and multiple power conversion circuits. During the startup process, the series / parallel relays are engaged first, followed by the power conversion circuits. However, residual voltage within the power conversion circuits can generate inrush currents after the relays are engaged, affecting their lifespan. Related technologies primarily address the residual voltage in the power conversion circuits through passive discharge methods, such as adding loads and switching circuits. However, this method increases design costs, complicates control logic, reduces the converter's energy conversion efficiency, and negatively impacts the user experience. Summary of the Invention

[0003] This application aims to at least solve one of the technical problems existing in the prior art. To this end, this application proposes a power converter and a control method for the power converter, which reduces the impact of the current generated by the residual voltage of the capacitor on the relay after the series / parallel relay is closed, reduces the probability of contact sticking, extends the service life, and improves the start-up speed of the power converter while maintaining the energy conversion efficiency of the power converter.

[0004] In a first aspect, this application provides a power converter, which includes: At least two power conversion circuits; one end of each power conversion circuit is used to connect to the DC bus input side, and the other end is used to connect to the output side; each power conversion circuit includes at least one capacitor; A controller is used to control the switching of the switching devices in the power conversion circuit so that the residual voltage of the capacitor in the power conversion circuit is reduced to a target threshold within a first time period.

[0005] According to the power converter of this application, the capacitor is actively discharged by controlling the opening and closing of the switching devices in the power conversion circuit, so that the residual voltage of the capacitor in the power conversion circuit is reduced to the target threshold within a first time period. The residual voltage of the capacitor can be consumed quickly without adding load or setting up additional switching circuit. This reduces the impact of the current generated by the residual voltage of the capacitor on the relay after the series / parallel relay is closed, reduces the probability of contact sticking, and extends the service life. Moreover, the control logic is simple and the implementation cost is low. While maintaining the energy conversion efficiency of the power converter, it can improve the start-up speed of the power converter. It is especially suitable for off-grid energy storage systems and other systems with high requirements for backup power continuity, and has universality.

[0006] According to one embodiment of this application, the power conversion circuit includes an isolation circuit and at least one bridge circuit connected to the isolation circuit, the bridge circuit being connected in parallel with the capacitor; the controller is configured to: The switching transistors in the target bridge arm of the bridge circuit are controlled to reduce the residual voltage of the power conversion circuit to the target threshold within a first time period.

[0007] According to one embodiment of this application, the controller is used for: All switches in the first target bridge arm of the upper and lower bridge arms are disconnected, and each switch in the other bridge arm is turned on for a corresponding duration within a switching cycle, and the overlap duration of the two switches being in the on state at the same time is less than or equal to the second duration.

[0008] According to one embodiment of this application, the controller is used for: All switches in the second target bridge arm of the control left and right bridge arms are turned off, while the switches in the other bridge arm are turned on alternately within one switching cycle.

[0009] According to one embodiment of this application, a series switch is provided between the power conversion circuits, and the controller is used for: The series switch is controlled to open before the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, thereby controlling the switching devices within the power conversion circuit to open.

[0010] According to one embodiment of this application, a parallel switch is provided between the power conversion circuit and the DC bus input side, and the controller is used for: The parallel switch is controlled to open before the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, thereby controlling the switching devices within the power conversion circuit to open.

[0011] According to one embodiment of this application, a bus relay is provided between the power conversion circuit and the DC bus input side; and / or, a first relay is provided between the power conversion circuit and the output side; the controller is used for: Before the switching devices in the power conversion circuit are switched on and off, so that the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, at least one of the bus relay and the first relay is switched off.

[0012] According to one embodiment of this application, the controller is used for: When the state of charge of the energy storage battery connected to the output side is greater than the first charge threshold, and the switching device for discharging is located between the isolation circuit in the power conversion circuit and the energy storage battery, the bus relay is controlled to disconnect.

[0013] According to one embodiment of this application, the controller is used for: When the voltage of the DC bus is greater than a first voltage threshold and the switching device for discharging is located between the isolation circuit in the power conversion circuit and the DC bus side, the bus relay is controlled to disconnect.

[0014] According to one embodiment of this application, the power converter is a DC converter.

[0015] Secondly, this application provides a control method for a power converter, the power converter including at least two power conversion circuits; one end of each power conversion circuit is connected to the DC bus input side, and the other end is connected to the output side; each power conversion circuit includes at least one capacitor; the method includes: The switching devices within the power conversion circuit are controlled to reduce the residual voltage of the capacitor in the power conversion circuit to a target threshold within a first time period.

[0016] According to the control method of the power converter in this application, the capacitor is actively discharged by controlling the opening and closing of the switching devices in the power conversion circuit, so that the residual voltage of the capacitor in the power conversion circuit is reduced to the target threshold within the first time period. The residual voltage of the capacitor can be consumed quickly without adding load or setting up additional switching circuit. This reduces the impact of the current generated by the residual voltage of the capacitor on the relay after the series / parallel relay is closed, reduces the probability of contact sticking, and extends the service life. Moreover, the control logic is simple and the implementation cost is low. While maintaining the energy conversion efficiency of the power converter, it can improve the start-up speed of the power converter. It is especially suitable for off-grid energy storage systems and other systems with high requirements for backup power continuity, and has universality. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is one of the flowcharts illustrating the control method for a power converter provided in the embodiments of this application; Figure 2 This is one of the structural schematic diagrams of the power converter provided in the embodiments of this application; Figure 3 This is a second schematic diagram of the power converter provided in the embodiments of this application; Figure 4This is a second schematic flowchart of the control method for the power converter provided in the embodiments of this application; Figure 5 This is a schematic diagram of the structure of the control device for the power converter provided in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0019] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0020] The power converter, power converter control method, power converter control device, electronic device, and readable storage medium provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0021] The control method for the power converter can be applied to the terminal, and can be executed by the hardware or software in the terminal.

[0022] The power converter control method provided in this application embodiment can be executed by a functional module or functional entity in the power converter that can implement the power converter control method, or by a controller electrically connected to the power converter.

[0023] like Figure 2 As shown, the power converter includes at least two power conversion circuits and a controller. One end of each power conversion circuit is connected to the DC bus input side, and the other end is connected to the output side. Figure 3 As shown, the power conversion circuit includes: an isolation circuit, at least one bridge circuit connected to the isolation circuit, and capacitors connected in parallel with the positive and negative terminals of the bridge circuit.

[0024] like Figure 2 As shown, in some embodiments, a series switch S3 is provided between the power conversion circuits, and / or a parallel switch is provided between the power conversion circuit and the DC bus input side, such as a parallel switch S2 connected to the power conversion circuit 101 and a parallel switch S1 connected to the power conversion circuit 102.

[0025] In some embodiments, the power converter is a DC-DC converter.

[0026] It is understandable that during the startup process of a power converter, the shunt switch or series switch is usually activated first before the power conversion circuit is started. Before the shunt switch or series switch is activated, there is a residual voltage in the capacitor of the power conversion circuit, and the residual voltage may be different for different power conversion circuits.

[0027] The controller is used to control the switching of the switching devices in the power conversion circuit so that the residual voltage of the capacitor in the power conversion circuit is reduced to the target threshold within a first time period.

[0028] The target threshold is a low value. By engaging the relay only after the residual capacitor voltage is less than or equal to the target threshold, the current generated by the residual voltage can be reduced or even eliminated, thereby reducing the current surge on the relay. In some embodiments, the target threshold can be set to 0 or a value close to 0.

[0029] The first duration is a relatively short duration. This first duration is less than the time required for the residual capacitor voltage to decrease to the target threshold under passive consumption.

[0030] In some embodiments, the controller is used to control the switching of switching devices in a power conversion circuit to reduce the residual capacitor voltage of the power conversion circuit to a target threshold within a first duration; including: the controller is used to control the switching of switching devices in any one of at least two power conversion circuits to reduce the residual capacitor voltage of the power conversion circuit to a target threshold within a first duration.

[0031] In some embodiments, a series switch is provided between the power conversion circuits, and the controller is used to: The series switch is controlled to open before the residual voltage of the power conversion circuit is reduced to the target threshold within a first time period.

[0032] In this embodiment, when the series switch is closed, the power conversion circuits are connected in series and then connected to the DC bus.

[0033] In some embodiments, a parallel switch is provided between the power conversion circuit and the DC bus input side, and the controller is used to: The parallel switch is controlled to open before the residual voltage of the power conversion circuit is reduced to the target threshold within a first time period, thus controlling the switching devices within the power conversion circuit to open.

[0034] In this embodiment, with the parallel switch closed, each power conversion circuit is connected in parallel to the DC bus.

[0035] In actual operation, after the power converter starts up and both the parallel and series switches are off, the switching devices in the power conversion circuit are controlled to open and close to actively discharge the capacitor. This allows the residual voltage of the capacitor to drop rapidly to the target threshold in a short time. After the residual voltage of the capacitor drops to the target threshold, the series or parallel switches are then controlled to close to form an effective series-parallel circuit. This can reduce or even eliminate the inrush current and extend the service life of the relay.

[0036] According to the power converter provided in the embodiments of this application, the capacitor is actively discharged by controlling the opening and closing of the switching devices in the power conversion circuit, so that the residual voltage of the capacitor in the power conversion circuit is reduced to the target threshold within a first time period. The residual voltage of the capacitor can be consumed quickly without adding load or setting up additional switching circuit. This reduces the impact of the current generated by the residual voltage of the capacitor on the relay after the series / parallel switch is closed, reduces the probability of contact sticking, and extends the service life. Moreover, the control logic is simple and the implementation cost is low. While maintaining the energy conversion efficiency of the power converter, it can improve the start-up speed of the power converter. It is especially suitable for systems with high requirements for backup power continuity, such as off-grid energy storage systems, and has universality.

[0037] The specific control methods for the switching transistor are explained below.

[0038] like Figure 3 As shown, in some embodiments, the controller is used to: The switching transistors in the target bridge arm of the control bridge circuit are turned on and off so that the residual voltage of the power conversion circuit is reduced to the target threshold within the first time period.

[0039] In this embodiment, the power conversion circuit includes an isolation circuit and at least one bridge circuit connected to the isolation circuit, the bridge circuit being connected in parallel with a capacitor.

[0040] Isolation circuits may include isolation transformers and inductors; Alternatively, it may include: isolation transformer, resonant capacitor, magnetizing inductor and resonant inductor; Alternatively, it may include: an isolation transformer, a primary resonant capacitor, a primary resonant inductor, a secondary resonant inductor, and a secondary resonant capacitor.

[0041] When a power converter includes multiple power conversion circuits, the topology of the isolation circuits included in each power conversion circuit can be the same or different.

[0042] The bridge circuit used for control can be any bridge circuit connected to the isolation circuit, and can be based on user-defined settings; no limitations are imposed here. The target bridge arm is a portion of the bridge arm in the controlled bridge circuit.

[0043] like Figure 3 As shown, each bridge arm is equipped with at least one switching transistor, and each switching transistor is connected in parallel with an internal diode.

[0044] like Figure 2 As shown, the following description uses a power converter including power conversion circuit 101 and power conversion circuit 102 as an example. If power conversion circuit 101 and power conversion circuit 102 are respectively as follows... Figure 3 In the topology shown, with bridge circuits connected to both ends of the isolation circuit, namely bridge circuit 1 and bridge circuit 2, capacitor C is connected in parallel to the positive and negative ports of bridge circuit 1, and capacitor C is connected in parallel to the positive and negative ports of bridge circuit 2.

[0045] Controlling the switching on and off of the transistors within the target bridge arm of a bridge circuit can include: Control the switching of the switching transistor in the target bridge arm of the bridge circuit 1 in the power conversion circuit 101 or the power conversion circuit 102; And / or, The switching transistors in the target bridge arm of the bridge circuit 2 in the power conversion circuit 101 or power conversion circuit 102 are switched on and off.

[0046] In some embodiments, the controller is used to: All switches in the first target bridge arm of the upper and lower bridge arms are disconnected, and each switch in the other bridge arm is turned on for a corresponding duration within a switching cycle, and the overlap duration of the two switches being in the on state at the same time is less than or equal to the second duration.

[0047] In this embodiment, the first target bridge arm is either the upper or lower bridge arm, and the other bridge arm is the remaining bridge arm among the upper and lower bridge arms excluding the first target bridge arm. The first target bridge arm can be determined based on the connection relationship between the bridge circuit and the isolation circuit.

[0048] In some embodiments, the first target bridge arm is the lower bridge arm, and the other bridge arm is the upper bridge arm.

[0049] The second duration is a smaller value and can be set by the user. When the second duration is zero, the switches in the other arm alternately turn on within one switching cycle.

[0050] When the switching transistors are turned on alternately, the on-time of the switching transistors within a switching cycle can be the same or different, such as turning on with a 5:5 duration, or turning on with a 2:8 or 7:3 duration, etc. This application does not limit this.

[0051] In actual control process, such as Figure 3 As shown, taking bridge circuit 1 as an example, switch K1 and switch K2 are set in the upper bridge arm, switch K4 and switch K3 are set in the lower bridge arm, and capacitor C1 is connected in parallel with bridge circuit 1.

[0052] If the first target bridge arm is the lower bridge arm, then the switches K4 and K3 in the lower bridge arm can be controlled to remain in the off state during the switching cycle, while the switches K1 and K2 in the upper bridge arm alternately emit waves. Alternatively, the switches K1 and K2 in the upper bridge arm can be controlled to have a brief overlap of waves within a switching cycle. The residual voltage of capacitor C1 can be consumed by switching K1 and K2.

[0053] Taking bridge circuit 2 as an example, switch K5 and switch K6 are set in the upper bridge arm, switch K7 and switch K8 are set in the lower bridge arm, and capacitor C2 is connected in parallel with bridge circuit 2.

[0054] If the first target bridge arm is the upper bridge arm, then the switches in the upper bridge arm K5 and K6 can be controlled to remain in the off state during the switching cycle, while the switches in the lower bridge arm K7 and K8 alternately emit waves, or the switches in the lower bridge arm K7 and K8 can be controlled to have a brief wave overlap within a switching cycle, and the residual voltage of capacitor C2 can be consumed by switching K7 and K8.

[0055] If the first target bridge arm is the lower bridge arm, then the switches K7 and K8 in the lower bridge arm can be controlled to remain off during the switching cycle, while the switches K5 and K6 in the upper bridge arm alternately emit waves. Alternatively, the switches K5 and K6 in the upper bridge arm can be controlled to have a brief overlap in their emission within one switching cycle. The residual voltage of capacitor C2 can be consumed by switching K5 and K6.

[0056] In some embodiments, the controller is used to: The control system disconnects all switches in the second target bridge arm of the left and right bridge arms, while the switches in the other bridge arm are alternately turned on within one switching cycle.

[0057] In this embodiment, the second target bridge arm is either the left or right bridge arm, and the other bridge arm is the remaining bridge arm between the left and right bridge arms excluding the second target bridge arm.

[0058] In the other arm, each switch is turned on alternately within a switching cycle. This includes the following: the switching duration of each switch within a switching cycle can be the same or different, such as turning on with a duration of 5:5, or turning on with a duration of 2:8, 7:3, etc. This application does not limit this.

[0059] In actual control process, such as Figure 3 As shown, taking bridge circuit 1 as an example, switch K1 and switch K4 are set in the left bridge arm, switch K2 and switch K3 are set in the right bridge arm, and capacitor C1 is connected in parallel with bridge circuit 1.

[0060] If the second target bridge arm is the left bridge arm, then the switches in K1 and K4 in the left bridge arm can be controlled to remain in the off state during the switching cycle, while the switches K2 and K3 in the right bridge arm alternately emit waves. The residual voltage of capacitor C1 is consumed by the alternating emission of the switches K2 and K3.

[0061] If the second target bridge arm is the right bridge arm, then the switches K2 and K3 in the right bridge arm can be controlled to remain in the off state during the switching cycle, while the switches K1 and K4 in the left bridge arm alternately emit waves. The residual voltage of capacitor C1 is consumed by the alternating emission of the switches K1 and K4.

[0062] Taking bridge circuit 2 as an example, switch K5 and switch K8 are set in the left bridge arm, switch K6 and switch K7 are set in the right bridge arm, and capacitor C2 is connected in parallel with bridge circuit 2.

[0063] If the second target bridge arm is the left bridge arm, then the switches in K5 and K8 in the left bridge arm can be controlled to remain in the off state during the switching cycle, while the switches K6 and K7 in the right bridge arm alternately emit waves. The residual voltage of capacitor C2 is consumed by the alternating emission of switches K6 and K7.

[0064] If the second target bridge arm is the right bridge arm, then the switching transistors K6 and K7 in the right bridge arm can be controlled to remain in the off state during the switching cycle, while the switching transistors K5 and K8 in the left bridge arm alternately emit waves. The residual voltage of capacitor C2 is consumed by the alternating emission of switching transistors K5 and K8.

[0065] It should be noted that during the actual control process, it is necessary to avoid the simultaneous emitting of waveforms by the switching transistors controlling the upper and lower bridge arms, which could lead to a short circuit.

[0066] The power converter provided in the embodiments of this application controls the active discharge of the capacitor by providing a variety of control methods for the switching transistors, which has high flexibility.

[0067] like Figure 2As shown, in some embodiments, a bus relay is provided between the power conversion circuit and the DC bus input side; and / or, a first relay is provided between the power conversion circuit and the output side; the controller is used to: The switching devices within the control power conversion circuit are switched on and off so that the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, at least one of the control bus relay and the first relay is disconnected.

[0068] In this embodiment, the DC bus input side is used for DC bus connection, and the output side is connected to the energy storage battery.

[0069] In actual operation, before controlling the switching transistor to consume the residual voltage of the capacitor, the path between the DC bus, the power conversion circuit, and the energy storage battery should be cut off, so that the capacitor can be actively discharged through the switching transistor.

[0070] In some embodiments, the controller is used to: When the state of charge of the energy storage battery connected to the output side is greater than the first charge threshold, and the switching device used for discharging is located between the isolation circuit in the power conversion circuit and the energy storage battery, the control bus relay is disconnected.

[0071] In this embodiment, the first charge threshold can be based on a user-defined setting. In some embodiments, the first charge threshold can be a full charge threshold.

[0072] When the state of charge of the energy storage battery is greater than the first charge threshold, it indicates that the energy storage battery has reached a fully charged state. At this time, the energy storage battery should not be charged anymore. The bus relay should be controlled to disconnect, cutting off the energy flow path between the DC bus and the energy storage battery, and preventing energy from being absorbed from the bus to charge the energy storage battery.

[0073] In some embodiments, the controller is used to: When the voltage of the DC bus is greater than the first voltage threshold and the switching device used for discharging is located between the isolation circuit in the power conversion circuit and the DC bus side, the control bus relay is disconnected.

[0074] In this embodiment, the first voltage threshold is a relatively high voltage value. If the DC bus voltage is greater than the first voltage threshold, it indicates that the DC bus can no longer absorb external energy. Therefore, the bus relay should be controlled to disconnect, thereby cutting off the energy flow path to the DC bus and preventing the energy storage battery from discharging to the DC bus.

[0075] According to the power converter provided in the embodiments of this application, while controlling the opening and closing of the switching transistor to actively discharge the capacitor, the energy flow path can be further adjusted by combining the opening and closing control of the bus relay and the first relay to ensure that the energy storage battery is not charged when it is fully charged, the energy storage battery is not discharged when it is fully discharged, and the energy storage battery does not discharge to the DC bus when the DC bus voltage is high, thus ensuring the normal operation of the system.

[0076] This application also provides a control method for a power converter.

[0077] like Figure 1 As shown, the control method of the power converter includes step 110.

[0078] Step 110: Control the switching devices in the power conversion circuit to reduce the residual voltage of the capacitor in the power conversion circuit to the target threshold within the first time period.

[0079] In this step, the power converter includes at least two power conversion circuits; one end of each power conversion circuit is used to connect to the DC bus input side, and the other end is used to connect to the output side; the power conversion circuit includes at least one capacitor.

[0080] In some embodiments, step 110 includes: All switches in the first target bridge arm of the upper and lower bridge arms are disconnected, and each switch in the other bridge arm is turned on for a corresponding duration within a switching cycle, and the overlap duration of the two switches being in the on state at the same time is less than the second duration.

[0081] like Figure 2 As shown, in some embodiments, the power conversion circuit includes an isolation circuit and at least one bridge circuit connected to the isolation circuit, the bridge circuit being connected in parallel with a capacitor; step 110 includes: The control system disconnects all switches in the second target bridge arm of the left and right bridge arms, while the switches in the other bridge arm are alternately turned on within one switching cycle.

[0082] According to the control method of the power converter provided in the embodiments of this application, the capacitor is actively discharged by controlling the opening and closing of the switching devices in the power conversion circuit, so that the residual voltage of the capacitor in the power conversion circuit is reduced to the target threshold within a first time period. The residual voltage of the capacitor can be consumed quickly without adding load or setting up additional switching circuit. This reduces the impact of the current generated by the residual voltage of the capacitor on the relay after the series / parallel relay is closed, reduces the probability of contact sticking, and extends the service life. Moreover, the control logic is simple and the implementation cost is low. While maintaining the energy conversion efficiency of the power converter, it can improve the start-up speed of the power converter. It is especially suitable for systems with high requirements for backup power continuity, such as off-grid energy storage systems, and has universality.

[0083] In some embodiments, a series switch is provided between the power conversion circuits, and before step 110, the method includes: controlling the series switch to open.

[0084] In some embodiments, a parallel switch is provided between the power conversion circuit and the DC bus input side. Before step 110, the method includes: controlling the parallel switch to open.

[0085] In some embodiments, such as Figure 4 As shown, after step 110, the method includes: Control the closing of parallel or series switches.

[0086] In actual operation, after the power converter starts up, the series and parallel switches are kept open. Based on the control method in step 110, the switching transistor is turned on to actively discharge the capacitor until the residual voltage of the capacitor drops to the target threshold. Then, the parallel or series switch is closed to form an effective series-parallel circuit, and the power converter operates normally. Upon receiving a shutdown command, the power converter stops power conversion and the series or parallel switch is turned off.

[0087] In some embodiments, a bus relay is provided between the power conversion circuit and the DC bus input side; and / or, a first relay is provided between the power conversion circuit and the output side; prior to step 110, the method includes: At least one of the control bus relay and the first relay is disconnected.

[0088] In some embodiments, disconnecting at least one of the control bus relay and the first relay includes: When the voltage of the DC bus is greater than the first voltage threshold and the switching device used for discharging is located between the isolation circuit in the power conversion circuit and the DC bus side, the control bus relay is disconnected.

[0089] In some embodiments, disconnecting at least one of the control bus relay and the first relay includes: When the state of charge of the energy storage battery connected to the output side is greater than the first charge threshold, and the switching device used for discharging is located between the isolation circuit in the power conversion circuit and the energy storage battery, the control bus relay is disconnected.

[0090] The power converter control method provided in this application can be executed by a power converter control device. This application uses the example of a power converter control device executing the power converter control method to illustrate the power converter control device provided in this application.

[0091] This application also provides a control device for a power converter.

[0092] like Figure 5 As shown, the power converter includes at least two power conversion circuits; one end of each power conversion circuit is used to connect to the DC bus input side, and the other end is used to connect to the output side; the power conversion circuit includes at least one capacitor: first processing module 510.

[0093] The first processing module 510 is used to control the switching of the switching devices in the power conversion circuit so that the residual voltage of the capacitor in the power conversion circuit is reduced to the target threshold within a first time period.

[0094] According to the control device of the power converter provided in the embodiments of this application, the capacitor is actively discharged by controlling the opening and closing of the switching devices in the power conversion circuit, so that the residual voltage of the capacitor in the power conversion circuit is reduced to the target threshold within a first time period. The residual voltage of the capacitor can be consumed quickly without adding load or setting up additional switching circuit. This reduces the impact of the current generated by the residual voltage of the capacitor on the relay after the series / parallel relay is closed, reduces the probability of contact sticking, and extends the service life. Moreover, the control logic is simple and the implementation cost is low. While maintaining the energy conversion efficiency of the power converter, it can improve the start-up speed of the power converter. It is especially suitable for systems with high requirements for backup power continuity, such as off-grid energy storage systems, and has universality.

[0095] In some embodiments, the power conversion circuit includes an isolation circuit and at least one bridge circuit connected to the isolation circuit, the bridge circuit being connected in parallel with a capacitor; the first processing module 510 is configured to: All switches in the first target bridge arm of the upper and lower bridge arms are disconnected, and each switch in the other bridge arm is turned on for a corresponding duration within a switching cycle, and the overlap duration of the two switches being in the on state at the same time is less than the second duration.

[0096] In some embodiments, the power conversion circuit includes an isolation circuit and at least one bridge circuit connected to the isolation circuit, the bridge circuit being connected in parallel with a capacitor; the first processing module 510 is configured to: The control system disconnects all switches in the second target bridge arm of the left and right bridge arms, while the switches in the other bridge arm are alternately turned on within one switching cycle.

[0097] In some embodiments, a series switch is provided between the power conversion circuits, and the device includes a second processing module for: The series switch is controlled to open before the residual voltage of the power conversion circuit is reduced to the target threshold within a first time period.

[0098] In some embodiments, a parallel switch is provided between the power conversion circuit and the DC bus input side, and the device includes a third processing module for: The parallel switch is controlled to open before the residual voltage of the power conversion circuit is reduced to the target threshold within a first time period, thus controlling the switching devices within the power conversion circuit to open.

[0099] In some embodiments, a bus relay is provided between the power conversion circuit and the DC bus input side; and / or, a first relay is provided between the power conversion circuit and the output side; the device includes a fourth processing module for: The switching devices within the control power conversion circuit are switched on and off so that the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, at least one of the control bus relay and the first relay is disconnected.

[0100] In some embodiments, the fourth processing module is configured to: When the state of charge of the energy storage battery connected to the output side is greater than the first charge threshold, and the switching device used for discharging is located between the isolation circuit in the power conversion circuit and the energy storage battery, the control bus relay is disconnected.

[0101] In some embodiments, the fourth processing module is configured to: When the voltage of the DC bus is greater than the first voltage threshold and the switching device used for discharging is located between the isolation circuit in the power conversion circuit and the DC bus side, the control bus relay is disconnected.

[0102] The control device for the power converter in this application embodiment can be an electronic device or a component within an electronic device, such as an integrated circuit or a chip. The electronic device can be a terminal or other devices besides a terminal. For example, the electronic device can be a mobile phone, tablet computer, laptop computer, PDA, in-vehicle electronic device, mobile internet device (MID), augmented reality (AR) / virtual reality (VR) device, robot, wearable device, ultra-mobile personal computer (UMPC), netbook, or personal digital assistant (PDA), etc. It can also be a server, network attached storage (NAS), personal computer (PC), television (TV), ATM, or self-service machine, etc. This application embodiment does not specifically limit the scope of the device.

[0103] The control device for the power converter in this embodiment can be a device with an operating system. This operating system can be Android, iOS, or other possible operating systems; this embodiment does not specifically limit the specific operating system used.

[0104] The control device for the power converter provided in this application embodiment can achieve... Figure 1 and Figure 4 The various processes implemented in the method implementation examples will not be described again here to avoid repetition.

[0105] In some embodiments, such as Figure 6 As shown, this application embodiment also provides an electronic device 600, including a processor 601, a memory 602, and a computer program stored in the memory 602 and executable on the processor 601. When the program is executed by the processor 601, it implements the various processes of the control method embodiment of the power converter described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0106] It should be noted that the electronic devices in the embodiments of this application include the mobile electronic devices and non-mobile electronic devices described above.

[0107] This application also provides a non-transitory computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the various processes of the control method embodiment of the power converter described above and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0108] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0109] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the control method of the power converter described above.

[0110] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0111] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the control method embodiment of the power converter described above, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0112] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0113] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0114] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0115] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0116] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0117] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A power converter, characterized in that, include: At least two power conversion circuits; one end of each power conversion circuit is used to connect to the DC bus input side, and the other end is used to connect to the output side; each power conversion circuit includes at least one capacitor; A controller is used to control the switching of the switching devices in the power conversion circuit so that the residual voltage of the capacitor in the power conversion circuit is reduced to a target threshold within a first time period.

2. The power converter according to claim 1, characterized in that, The power conversion circuit includes an isolation circuit and at least one bridge circuit connected to the isolation circuit, the bridge circuit being connected in parallel with the capacitor; the controller is used for: The switching transistors in the target bridge arm of the bridge circuit are controlled to reduce the residual voltage of the power conversion circuit to the target threshold within a first time period.

3. The power converter according to claim 2, characterized in that, The controller is used for: All switches in the first target bridge arm of the upper and lower bridge arms are disconnected, and each switch in the other bridge arm is turned on for a corresponding duration within a switching cycle, and the overlap duration of the two switches being in the on state at the same time is less than or equal to the second duration.

4. The power converter according to claim 2, characterized in that, The controller is used for: All switches in the second target bridge arm of the control left and right bridge arms are turned off, while the switches in the other bridge arm are turned on alternately within one switching cycle.

5. The power converter according to any one of claims 1-4, characterized in that, A series switch is provided between the power conversion circuits, and the controller is used for: The series switch is controlled to open before the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, thereby controlling the switching devices within the power conversion circuit to open.

6. The power converter according to any one of claims 1-4, characterized in that, A parallel switch is provided between the power conversion circuit and the DC bus input side, and the controller is used for: The parallel switch is controlled to open before the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, thereby controlling the switching devices within the power conversion circuit to open.

7. The power converter according to any one of claims 1-4, characterized in that, A bus relay is provided between the power conversion circuit and the DC bus input side; and / or, a first relay is provided between the power conversion circuit and the output side; the controller is used for: Before the switching devices in the power conversion circuit are switched on and off, so that the residual voltage of the power conversion circuit is reduced to a target threshold within a first time period, at least one of the bus relay and the first relay is switched off.

8. The power converter according to claim 7, characterized in that, The controller is used for: When the state of charge of the energy storage battery connected to the output side is greater than the first charge threshold, and the switching device for discharging is located between the isolation circuit in the power conversion circuit and the energy storage battery, the bus relay is controlled to disconnect.

9. The power converter according to claim 7, characterized in that, The controller is used for: When the voltage of the DC bus is greater than a first voltage threshold and the switching device for discharging is located between the isolation circuit in the power conversion circuit and the DC bus side, the bus relay is controlled to disconnect.

10. The power converter according to any one of claims 1-4, characterized in that, The power converter is a DC-DC converter.

11. A control method for a power converter, characterized in that, The power converter includes at least two power conversion circuits; one end of each power conversion circuit is connected to the DC bus input side, and the other end is connected to the output side; each power conversion circuit includes at least one capacitor; the method includes: The switching devices within the power conversion circuit are controlled to reduce the residual voltage of the capacitor in the power conversion circuit to a target threshold within a first time period.

12. The control method for the power converter according to claim 11, characterized in that, The power conversion circuit includes an isolation circuit and at least one bridge circuit connected to the isolation circuit, the bridge circuit being connected in parallel with the capacitor; controlling the switching of the switching devices within the power conversion circuit includes: All switches in the first target bridge arm of the upper and lower bridge arms are disconnected, and each switch in the other bridge arm is turned on for a corresponding duration in a switching cycle, and the overlap duration of the two switches being turned on at the same time is less than the second duration. or, All switches in the second target bridge arm of the control left and right bridge arms are turned off, while the switches in the other bridge arm are turned on alternately within one switching cycle.

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