Converter wave-enclosing control method, converter and chip

Abstract

The present application relates to a method for controlling the blocking wave of a converter, a converter and a chip. The converter includes an AC side half-bridge circuit, a filter capacitor and a controller. The filter capacitor is connected in parallel to the output end of the AC side half-bridge circuit. The method is used in the controller. The method includes: responding to the blocking wave signal corresponding to the converter, obtaining the current polarity of the AC side grid voltage, and controlling the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor. The use of the above-mentioned converter blocking wave control method can solve the voltage stress problem of the AC side half-bridge circuit during blocking wave, and avoid damage to the AC side switching devices.

Description

Technical Field

[0001] The present application relates to the technical field of converter control, and in particular to a converter envelope control method, a converter and a chip. Background Art

[0002] When blocking the converter that uses a half-bridge circuit on the AC side, if all the switches on the AC side are directly turned off, the energy stored in the transformer leakage inductance has no discharge path, which may easily cause problems such as overvoltage stress in the AC side half-bridge circuit connecting the converter to the grid, resulting in damage to the AC side switching devices.

[0003] Therefore, a method for controlling the blocking wave of a converter is urgently needed to solve the voltage stress problem of the half-bridge circuit on the AC side during blocking wave and avoid damage to the switching devices on the AC side. Summary of the invention

[0004] Based on this, it is necessary to provide a converter blocking control method, a converter and a chip that can solve the voltage stress risk of the AC side half-bridge circuit during blocking, in response to the above technical problems.

[0005] In a first aspect, the present application provides a method for controlling a converter wave capping, wherein the converter includes an AC side half-bridge circuit, a filter capacitor and a controller, the filter capacitor is connected in parallel to the output end of the AC side half-bridge circuit, and the method is used in the controller, and the method includes:

[0006] In response to the corresponding blocking wave signal of the converter, the current polarity of the AC side grid voltage is obtained, and the AC side half-bridge circuit is controlled to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor.

[0007] In one embodiment, controlling the AC side half-bridge circuit to operate according to a target freewheeling path corresponding to the current polarity includes:

[0008] When the current polarity is positive, the first switch device group is controlled to be turned on, and the second switch device group is controlled to be turned off;

[0009] When the current polarity is negative, the second switch device group is controlled to be turned on, and the first switch device group is controlled to be turned off;

[0010] The first switching device group includes two switching devices in the AC side half-bridge circuit, and the second switching device group includes another two switching devices in the AC side half-bridge circuit.

[0011] In one embodiment, the upper bridge arm circuit of the AC side half-bridge circuit includes a first switch device and a second switch device, the lower bridge arm circuit of the AC side half-bridge circuit includes a third switch device and a fourth switch device, and the second switch device and the third switch device are respectively connected to the midpoint of the bridge arm of the AC side half-bridge circuit;

[0012] Control the AC side half-bridge circuit to work according to the target freewheeling path corresponding to the current polarity, including:

[0013] When the current polarity is positive, the second switch device and the fourth switch device are controlled to be turned on, and the first switch device and the third switch device are controlled to be turned off;

[0014] When the current polarity is negative, the first switching device and the third switching device are controlled to be turned on, and the second switching device and the fourth switching device are controlled to be turned off.

[0015] In one embodiment, obtaining the current polarity of the AC side grid voltage includes:

[0016] Get the current phase of the AC side grid voltage;

[0017] The current polarity is determined based on the current phase.

[0018] In one embodiment, the method further comprises:

[0019] Get the current polarity of the AC side grid voltage, including:

[0020] Obtain the current instantaneous voltage of the AC side grid voltage;

[0021] Determine the current polarity based on the instantaneous voltage.

[0022] In one embodiment, the method further comprises:

[0023] In response to the wave-closing signal corresponding to the converter, obtaining the current power value corresponding to the half-bridge circuit on the AC side;

[0024] Based on the current power value and the capacitance of the filter capacitor, the preset duration is obtained.

[0025] In one embodiment, the preset duration ranges from 1 microsecond to 100 microseconds.

[0026] In a second aspect, the present application also provides a converter, including an AC side half-bridge circuit, a filter capacitor and a controller;

[0027] The filter capacitor is connected in parallel to the output end of the half-bridge circuit on the AC side;

[0028] The controller is used to respond to the corresponding wave-closing signal of the converter, obtain the current polarity of the AC side grid voltage, and control the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor.

[0029] In a third aspect, the present application further provides a chip including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method provided in the first aspect when executing the computer program.

[0030] The above-mentioned converter wave blocking control method, converter and chip, wherein the converter includes an AC side half-bridge circuit, a filter capacitor and a controller, the filter capacitor is connected in parallel at the output end of the AC side half-bridge circuit, and the method is used in the controller, the method includes: responding to the wave blocking signal corresponding to the converter, obtaining the current polarity of the AC side grid voltage, controlling the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor; in this way, using a filter capacitor with a larger capacitance to store leakage inductance energy can achieve rapid transfer of leakage inductance energy, reduce the voltage stress risk of the AC side switching device during the wave blocking process, and improve the reliability of the converter operation; at the same time, when selecting the target freewheeling path, consider the current polarity of the AC side grid voltage to avoid causing a short circuit in the AC side grid, thereby ensuring the safety of the converter wave blocking control. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] FIG1 is a circuit topology structure of a single-stage isolated grid-connected inverter in one embodiment;

[0033] Figure 2 A circuit topology structure of a single-stage isolated grid-connected inverter in another embodiment;

[0034] Figure 3 A schematic diagram of the control timing of the switch device in the AC side half-bridge circuit when the current polarity is positive in one embodiment;

[0035] Figure 4 A schematic diagram of the control timing of the switch device in the AC side half-bridge circuit when the current polarity is negative in one embodiment;

[0036] Figure 5 A schematic diagram of current flow direction of a target freewheeling path when the current polarity is positive in one embodiment;

[0037] Figure 6 A schematic diagram of the current flow direction of the target freewheeling path when the current polarity is negative in one embodiment;

[0038] Figure 7FIG. 4 is a flowchart of a converter envelope control method in one embodiment. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0041] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0042] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0043] It is understood that the term "based on" used in this application is used to describe one or more factors that affect the determination, and does not exclude other factors that may affect the determination. For example, the phrase "determine A based on B" means that the determination of A can be based entirely or at least partially on factor B, that is, B is a factor that affects the determination of A, but does not exclude that the determination of A is also based on C.

[0044] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0045] The converter wave-sealing control method provided in the embodiment of the present application can be used in a controller in a converter adopting a half-bridge circuit structure on the AC side, wherein the upper bridge arm and the lower bridge arm of the half-bridge circuit are both realized by a bidirectional switch, and the controller is at least connected to each switching device in the converter to control the on-off frequency, duty cycle and phase shift of each switching device. The converter can be a direct current alternating current (DC-AC) converter, such as a single-stage isolated grid-connected inverter, or an alternating current direct current (AC-DC) converter, such as a single-stage isolated rectifier.

[0046] Please refer to Figure 1 and Figure 2 , is a circuit topology of a single-stage isolated grid-connected inverter. Among them, V dc Indicates the DC side power supply voltage, V ac is the AC side grid voltage; the AC side half-bridge circuit includes an upper bridge arm circuit, a lower bridge arm circuit, and a resonant capacitor C p and resonant capacitor C n The upper bridge arm circuit is realized based on a bidirectional switch composed of switch devices Q5 and Q6, the lower bridge arm circuit is realized based on a bidirectional switch composed of switch devices Q7 and Q8, and the midpoint C of the bridge arm is connected to the leakage inductance L of the converter. r , the upper bridge arm circuit and the resonant capacitor C p Correspondingly, the lower bridge arm circuit and the resonant capacitor C n Correspondingly, the capacitor C p and capacitor C n Series, resonant capacitor C p and resonant capacitor C n The middle connection point D is connected to the transformer in the converter; the filter capacitor C o Connected in parallel at the output end of the half-bridge circuit on the AC side, the filter capacitor C o And filter resistor Z g In the technical field, if the converter is an inverter, the AC side is the output end, and the filter capacitor C o Also called output capacitance.

[0047] The controller in Figure 1 and Figure 2 Not shown in the figure, the controller can be implemented by using an MCU (Microcontroller Unit) chip; it can also be implemented based on a DSP (Digital Signal Processor) chip, an FPGA (Field-Programmable Gate Array) or a customized controller chip; the embodiments of the present application do not limit the specific implementation hardware of the controller.

[0048] Please refer to Figure 2, exemplarily, the DC side of the converter for which the converter wave-sealing control method provided in the embodiment of the present application is used can be implemented by an H-bridge circuit, wherein the first bridge arm circuit of the DC side H-bridge circuit includes a switch device Q1 and a switch device Q2, and the second bridge arm circuit includes a switch device Q3 and a switch device Q4, wherein point A and point B are load interfaces of the DC side H-bridge circuit, T r For transformer.

[0049] It should be noted that the embodiments of the present application do not limit the specific circuit structure adopted on the DC side. Figure 2 This is just an exemplary illustration.

[0050] Among them, the switching devices involved in the embodiments of the present application can also be called power switching tubes; illustratively, the switching devices can use MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or IGBT (Insulated Gate Bipolar Transistor). The present application does not limit the specific types and models of the switching devices.

[0051] In an exemplary embodiment, the converter includes an AC side half-bridge circuit, a filter capacitor and a controller. The filter capacitor is connected in parallel to the output end of the AC side half-bridge circuit. The converter provided in this embodiment is used in the controller for the converter sealing wave control method. The method includes: responding to the sealing wave signal corresponding to the converter, obtaining the current polarity of the AC side grid voltage, and controlling the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor.

[0052] The blocking signal can be based on an external shutdown command, or the controller can generate a blocking signal to shut down the converter when the converter's operating conditions meet the preset shutdown conditions. Figure 3 and Figure 4 , time t1 represents the time when the controller starts to respond to the wave-enclosing signal and perform wave-enclosing control after receiving the wave-enclosing signal.

[0053] Among them, the target freewheeling path refers to the freewheeling path that can transfer the leakage inductance energy to the filter capacitor; the target freewheeling path is constructed according to the current polarity of the AC side grid voltage, so that the leakage inductance energy can be quickly transferred to the filter capacitor, while avoiding causing a short circuit in the AC side grid.

[0054] In a possible implementation manner, the process of acquiring the current polarity of the AC side grid voltage includes: acquiring the current phase of the AC side grid voltage, and determining the current polarity according to the current phase.

[0055] Among them, the phase corresponding to the positive pole is 0° to 180°, and the phase corresponding to the negative pole is 180° to 360°. The boundary phases of the intervals such as 0°, 180° or 360°, that is, the phase of the zero-crossing point of the AC side grid voltage, can be confirmed as the positive pole or the negative pole.

[0056] In a possible implementation manner, the process of acquiring the current polarity of the AC side grid voltage includes: acquiring the current instantaneous voltage of the AC side grid voltage, and determining the current polarity according to the instantaneous voltage.

[0057] When the instantaneous voltage is positive, the current polarity is positive, and when the instantaneous voltage is negative, the current polarity is negative. When the current instantaneous voltage is 0, it can be determined as positive or negative.

[0058] The filter capacitor generally adopts a capacitor with a larger capacitance, about hundreds of nF (nanofarads) or uF (microfarads), and the resonant capacitor generally adopts a capacitor with a smaller capacitance, about tens of nF. The goal of constructing the target freewheeling path in this embodiment is to transfer the leakage inductance energy to the filter capacitor. Compared with the related art that releases the leakage inductance energy through the resonant capacitor, because the energy of the resonant capacitor is smaller, the leakage inductance energy is transferred back and forth between the leakage inductance and the resonant capacitor, and the energy release rate is slower, resulting in a large voltage stress risk for the AC side switching device during the wave closing process; in this embodiment, the leakage inductance energy is transferred to the filter capacitor. Because the capacitance of the filter capacitor is larger, it can quickly absorb the leakage inductance energy and reduce the voltage stress risk of the AC side switching device during the wave closing process.

[0059] The converter control method provided in this embodiment responds to the corresponding wave-closing signal of the converter, obtains the current polarity of the AC side grid voltage, and controls the AC side half-bridge circuit to work according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor. In this way, using a filter capacitor with a larger capacitance to store leakage inductance energy can achieve rapid transfer of leakage inductance energy, reduce the voltage stress risk of the AC side switch device during the wave-closing process, and improve the reliability of the converter operation; at the same time, when selecting the target freewheeling path, the current polarity of the AC side grid voltage is considered to avoid causing a short circuit in the AC side grid and ensure the safety of the converter wave-closing control.

[0060] After a large number of experiments, the applicant concluded that the converter wave-blocking control method provided by the embodiment of the present application can transfer the leakage inductance energy to the filter capacitor within the μs (microseconds) level, complete the discharge of the leakage inductance energy, and improve the reliability of the wave-blocking control; exemplary, the leakage inductance energy transfer time is less than 100 μs. In the prior art, the time required to release the leakage inductance energy through the resonant capacitor is generally at the ms (milliseconds) level, which is much longer than the time required by the converter wave-blocking control method provided by the embodiment of the present application.

[0061] In an exemplary embodiment, the AC side half-bridge circuit is controlled to operate according to the target freewheeling path corresponding to the current polarity, including: when the current polarity is positive, controlling the first switch device group to be turned on and controlling the second switch device group to be turned off; when the current polarity is negative, controlling the second switch device group to be turned on and controlling the first switch device group to be turned off.

[0062] The first switching device group includes two switching devices in the AC side half-bridge circuit, and the second switching device group includes another two switching devices in the AC side half-bridge circuit.

[0063] In a possible implementation of this embodiment, the upper bridge arm circuit of the AC side half-bridge circuit includes a first switch device and a second switch device, the lower bridge arm circuit of the AC side half-bridge circuit includes a third switch device and a fourth switch device, and the second switch device and the third switch device are respectively connected to the midpoint of the bridge arm of the AC side half-bridge circuit. Figure 2 The circuit topology structure, the first switch device in this embodiment is shown in Figure 1 and Figure 2 The switch device Q5 in FIG. 1 and the second switch device Figure 2 The switching device Q6 in FIG. 1 and the third switching device Figure 2 The switch device Q7 in FIG. 1 and FIG. Figure 2 The switching device Q8 in.

[0064] In this embodiment, the first switch device group includes the second switch device and the fourth switch device, and the third switch device includes the first switch device and the fourth switch device. Wherein, controlling the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity includes: when the current polarity is positive, controlling the second switch device and the fourth switch device to turn on, and controlling the first switch device and the third switch device to turn off; when the current polarity is negative, controlling the first switch device and the third switch device to turn on, and controlling the second switch device and the fourth switch device to turn off.

[0065] Please refer to Figure 3 and Figure 5 ,in, Figure 3 It is a control timing diagram of the switch device of the AC side half-bridge circuit when the current polarity is positive. Figure 5 Schematic diagram of the current flow direction of leakage inductance energy transferred according to the target freewheeling path when the current polarity is positive. Figure 3As shown, before time t1, the AC side grid voltage is in the positive half cycle, regardless of whether it is outside the zero-crossing interval at this time, the control mode of the AC side half-bridge circuit is the first mode, that is, the switch device Q6 and the switch device Q8 are constantly turned on, and the switch device Q5 and the switch device Q7 are turned on at high frequency and complementary, or it is within the zero-crossing interval. The control mode of the AC side half-bridge circuit is the second mode (the second mode is not specifically limited in this application), at time t1, the switch device Q5 and the switch device Q7 are controlled to be turned off, and the switch device Q6 and the switch device Q8 are turned on.

[0066] Please refer to Figure 5 In (a), at time t1, the leakage inductance L r The current direction at is from the leakage inductance L r Flows to point C, at which point the leakage inductance energy through the target freewheeling path is transferred to the resonant capacitor C through the anti-parallel diode in the turned-on switch device Q6 and the turned-off switch device Q5. p And filter capacitor C o ; Because the filter capacitor C o The capacitance is large, which can quickly absorb the leakage inductance energy and make the AC side half-bridge circuit safely blocked.

[0067] Please refer to Figure 5 In (b), at time t1, the leakage inductance L r The current direction at is from point C to the leakage inductance L r At this time, through the target freewheeling path, the leakage inductance energy is transferred to the resonant capacitor C through the anti-parallel diode in the turned-on switch device Q8 and the turned-off switch device Q7. n And filter capacitor C o ; Because the filter capacitor C o The capacitance is large, which can quickly absorb the leakage inductance energy and make the AC side half-bridge circuit safely blocked.

[0068] Please refer to Figure 4 and Figure 6 ,in, Figure 4 It is a control timing diagram of the switch device of the AC side half-bridge circuit when the current polarity is negative. Figure 6 Schematic diagram of the current flow direction of leakage inductance energy transferred according to the target freewheeling path when the current polarity is negative. Figure 4 As shown, before time t1, the AC side grid voltage is in the negative half cycle. At this time, whether it is outside the zero-crossing interval, the control mode of the AC side half-bridge circuit is the first mode, that is, the switch device Q5 and the switch device Q7 are constantly turned on, and the switch device Q6 and the switch device Q8 are turned on at high frequency and complementary, or it is within the zero-crossing interval. The control mode of the AC side half-bridge circuit is the second mode, at time t1, the switch device Q6 and the switch device Q8 are controlled to be turned off, and the switch device Q5 and the switch device Q7 are turned on.

[0069] Please refer to Figure 6 In (a), at time t1, the leakage inductance L r The current direction at is from the leakage inductance L r Flows to point C, at which point the leakage inductance energy through the target freewheeling path is transferred to the resonant capacitor C through the anti-parallel diode in the turned-on switch device Q7 and the turned-off switch device Q8. n And filter capacitor C o ; Because the filter capacitor C o The capacitance is large, which can quickly absorb the leakage inductance energy and make the AC side half-bridge circuit safely blocked.

[0070] Please refer to Figure 6 In (b), at time t1, the leakage inductance L r The current direction at is from point C to the leakage inductance L r At this time, through the target freewheeling path, the leakage inductance energy is transferred to the resonant capacitor C through the anti-parallel diodes in the turned-on switch device Q5 and the turned-off switch device Q6. p And filter capacitor C o ; Because the filter capacitor C o The capacitance is large, which can quickly absorb the leakage inductance energy and make the AC side half-bridge circuit safely blocked.

[0071] Combination Figure 5 It can be seen that when the AC side grid voltage is positive, regardless of the leakage inductance L r The current direction is from the leakage inductance L r Flow to point C, or from point C to leakage inductance L r , the target freewheeling path provided in this embodiment can be used to continuously flow to the filter capacitor C along the first direction. o Charging; similarly, combining Figure 6 It can be seen that when the AC side grid voltage is negative, regardless of the leakage inductance L r The current direction is from the leakage inductance L r Flow to point C, or from point C to leakage inductance L r , the target freewheeling path provided in this embodiment can be used to continuously flow to the filter capacitor C along the second direction. o Thus, the converter wave control method provided in this embodiment can continuously charge the filter capacitor C in one direction. o Charging can achieve the effect of quickly transferring the leakage inductance energy to the filter capacitor for storage, reducing the voltage stress risk of the AC side switch device during the blocking wave, and improving the reliability of the converter operation; at the same time, the converter blocking wave control method provided in this embodiment does not need to judge the leakage inductance L at the blocking wave moment. r The current direction at the point avoids the related art based on the leakage inductance L rWhen the freewheeling path is selected according to the current direction at the AC side, there may be a risk of voltage stress on the AC side switching devices due to misjudgment of the current direction.

[0072] Furthermore, even if the polarity of the AC side grid voltage is not accurately determined near the zero crossing point, since the AC side voltage value near the zero crossing point is small, the leakage inductance energy is small, and the short-term direct conduction generally does not cause stress risk to the switching device. At the same time, the target freewheeling path provided in this embodiment can still ensure that the leakage inductance energy is within the leakage inductance L. r and resonant capacitor C p Or resonant capacitor C n Bidirectional flow between them further avoids the risk of device stress.

[0073] In an exemplary embodiment, after detecting the leakage inductance L r When the current value at is less than a preset threshold, all switching devices of the AC side half-bridge circuit are controlled.

[0074] In an exemplary embodiment, a preset duration of freewheeling operation according to a target freewheeling path is preconfigured; after the AC side half-bridge circuit is controlled to operate according to the target freewheeling path for the preset duration, all switching devices of the AC side half-bridge circuit are controlled to be turned off. For example, please refer to Figure 3 and Figure 4 , at time t2, all the switching devices of the AC side half-bridge circuit are controlled to be turned off. Figure 3 and Figure 4 ΔT in is the preset time length.

[0075] In a possible implementation, the provided converter wave blocking control method also includes: obtaining a current power value corresponding to the AC side half-bridge circuit in response to a wave blocking signal corresponding to the converter; and obtaining a preset duration based on the current power value and the capacitance of the filter capacitor.

[0076] In this embodiment, the preset duration is obtained based on the current operating rate value corresponding to the AC side half-bridge circuit and the capacitance of the filter capacitor when the wave-blocking signal is received, so as to improve the accuracy of the freewheeling working duration of the wave-blocking process.

[0077] In another possible implementation, in the converter envelope control method provided, the preset duration of operation of the target freewheeling path is configured in advance based on empirical values ​​determined in a large number of experiments.

[0078] After a large number of experiments, the applicant found that the time for transferring the leakage inductance energy during the blocking process to the filter capacitor through the target freewheeling path is at the μs (microsecond) level, generally less than 100μs. Optionally, the preset time range is 1μs to 100μs; preferably, the preset time range is 1μs to 10μs. In this embodiment, the preset time of the freewheeling operation is configured in advance according to the empirical value, which can save the real-time power value collection of the AC side half-bridge circuit during the blocking process and the calculation process of the preset time, thereby improving the blocking control efficiency.

[0079] In this embodiment, the working time of the freewheeling path is controlled according to the determined preset time length, compared with the real-time acquisition of the leakage inductance L r The current value at the AC side is used to determine the method of shutting down all the switching devices of the half-bridge circuit on the AC side, without setting up an additional current sampling circuit, saving hardware resources and improving control efficiency.

[0080] In an exemplary embodiment, the converter includes an AC side half-bridge circuit, a filter capacitor and a controller, the filter capacitor is connected in parallel to the output end of the AC side half-bridge circuit, the upper bridge arm circuit of the AC side half-bridge circuit includes a first switch device and a second switch device, the lower bridge arm circuit of the AC side half-bridge circuit includes a third switch device and a fourth switch device, the second switch device and the third switch device are respectively connected to the midpoint of the bridge arm of the AC side half-bridge circuit; the converter provided in this embodiment is used in the controller, please refer to Figure 7 The method includes steps 702 to 708, wherein:

[0081] Step 702: In response to the wave-blocking signal corresponding to the converter, the current polarity of the AC side grid voltage and the current power value corresponding to the AC side half-bridge circuit are obtained.

[0082] Optionally, a current phase of the AC side grid voltage is obtained, and a current polarity is determined according to the current phase.

[0083] Optionally, the current instantaneous voltage of the AC side grid voltage is obtained, and the current polarity is determined according to the instantaneous voltage.

[0084] Step 704, obtaining a preset duration based on the current power value and the capacitance of the filter capacitor.

[0085] Step 706, determining whether the current polarity is positive.

[0086] Step 708: If the current polarity is positive, the first switch device and the third switch device are controlled to be directly turned off, and the second switch device and the fourth switch device are controlled to be turned on for a preset time and then turned off.

[0087] Step 710: If the current polarity is negative, the second switch device and the fourth switch device are controlled to be directly turned off, and the first switch device and the fourth switch device are controlled to be turned on for a preset time and then turned off.

[0088] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders, or multiple steps can be executed simultaneously. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0089] An embodiment of the present application also provides a converter, which includes an AC side half-bridge circuit, a filter capacitor and a controller; the filter capacitor is connected in parallel to the output end of the AC side half-bridge circuit; the controller is used to respond to the corresponding wave-blocking signal of the converter, obtain the current polarity of the AC side grid voltage, and control the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor.

[0090] In an exemplary embodiment, the controller is used to control the first switch device group to turn on and the second switch device group to turn off when the current polarity is positive; when the current polarity is negative, the controller is used to control the second switch device group to turn on and the first switch device group to turn off; wherein the first switch device group includes two switch devices in the AC side half-bridge circuit, and the second switch device group includes another two switch devices in the AC side half-bridge circuit.

[0091] In an exemplary embodiment, the upper bridge arm circuit of the AC side half-bridge circuit includes a first switching device and a second switching device, and the lower bridge arm circuit of the AC side half-bridge circuit includes a third switching device and a fourth switching device, and the second switching device and the third switching device are respectively connected to the midpoint of the bridge arm of the AC side half-bridge circuit; the controller is used to control the second switching device and the fourth switching device to be turned on when the current polarity is positive, and to control the first switching device and the third switching device to be turned off at the same time; when the current polarity is negative, the controller controls the first switching device and the third switching device to be turned on, and to control the second switching device and the fourth switching device to be turned off at the same time.

[0092] In an exemplary embodiment, the controller is further configured to obtain a current phase of the AC side grid voltage; and determine a current polarity according to the current phase.

[0093] In an exemplary embodiment, the controller is further configured to obtain a current instantaneous voltage of the AC side grid voltage; and determine a current polarity according to the instantaneous voltage.

[0094] In an exemplary embodiment, the controller is used to control all switching devices of the AC side half-bridge circuit to turn off after controlling the AC side half-bridge circuit to operate according to the target freewheeling path for a preset time period.

[0095] In an exemplary embodiment, the controller obtains the current power value corresponding to the AC side half-bridge circuit in response to the sealing signal corresponding to the converter; and obtains the preset duration based on the current power value and the capacitance of the filter capacitor.

[0096] In an exemplary embodiment, the preset duration ranges from 1 microsecond to 100 microseconds.

[0097] An embodiment of the present application further provides a chip, which includes a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps in the above-mentioned method embodiments when executing the computer program.

[0098] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0099] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0100] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0101] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0102] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0103] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for controlling a converter wave envelope, characterized in that: The converter comprises an AC side half-bridge circuit, a filter capacitor and a controller, the upper bridge arm circuit of the AC side half-bridge circuit comprises a first switch device and a second switch device, the lower bridge arm circuit of the AC side half-bridge circuit comprises a third switch device and a fourth switch device, the second switch device and the third switch device are respectively connected to the midpoint of the bridge arm of the AC side half-bridge circuit, the filter capacitor is connected in parallel to the output end of the AC side half-bridge circuit, the method is used in the controller, and the method comprises: In response to the wave-closing signal corresponding to the converter, the current polarity of the AC side grid voltage is obtained, and the AC side half-bridge circuit is controlled to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor; After controlling the AC side half-bridge circuit to operate according to the target freewheeling path for a preset time, all switching devices of the AC side half-bridge circuit are controlled to be turned off; The step of controlling the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity includes: When the current polarity is positive, controlling the second switch device and the fourth switch device to be turned on, and controlling the first switch device and the third switch device to be turned off; When the current polarity is negative, controlling the first switch device and the third switch device to be turned on, and controlling the second switch device and the fourth switch device to be turned off; The preset duration is determined according to the following steps: in response to the wave-closing signal corresponding to the converter, the current power value corresponding to the AC side half-bridge circuit is obtained, and the preset duration is obtained based on the current power value and the capacitance of the filter capacitor; or, The preset time length ranges from 1 microsecond to 100 microseconds.

2. The method according to claim 1, characterized in that The obtaining of the current polarity of the AC side grid voltage includes: Acquiring the current phase of the AC side grid voltage; The current polarity is determined based on the current phase.

3. The method according to claim 1, characterized in that The obtaining of the current polarity of the AC side grid voltage includes: Obtaining the current instantaneous voltage of the AC side power grid voltage; The current polarity is determined based on the instantaneous voltage.

4. A converter, characterized in that: The converter includes an AC side half-bridge circuit, a filter capacitor and a controller; The upper bridge arm circuit of the AC side half-bridge circuit includes a first switch device and a second switch device, the lower bridge arm circuit of the AC side half-bridge circuit includes a third switch device and a fourth switch device, and the second switch device and the third switch device are respectively connected to the midpoint of the bridge arm of the AC side half-bridge circuit; The filter capacitor is connected in parallel to the output end of the AC side half-bridge circuit; The controller is used to respond to the wave-closing signal corresponding to the converter, obtain the current polarity of the AC side grid voltage, control the AC side half-bridge circuit to operate according to the target freewheeling path corresponding to the current polarity to transfer the leakage inductance energy to the filter capacitor, and control all switching devices of the AC side half-bridge circuit to turn off after controlling the AC side half-bridge circuit to operate according to the target freewheeling path for a preset time; The controller is used to control the second switch device and the fourth switch device to be turned on and the first switch device and the third switch device to be turned off when the current polarity is positive, and to control the first switch device and the third switch device to be turned on and the second switch device and the fourth switch device to be turned off when the current polarity is negative; The controller is used to determine the preset duration according to the following steps: in response to the wave-closing signal corresponding to the converter, obtain the current power value corresponding to the AC side half-bridge circuit, and obtain the preset duration based on the current power value and the capacitance of the filter capacitor; or, The preset time length ranges from 1 microsecond to 100 microseconds.

5. A chip comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 3 are implemented.

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