Control device, computer readable storage medium, power converter and control method thereof

Abstract

The invention discloses a control device, a computer readable storage medium, a power converter and a control method thereof, and relates to the technical field of alternating current switches. The control method is applied to a controller in the power converter. When the controller executes the control method, initialization is carried out after the power converter is powered on; then, controlling an alternating-current switch on the alternating-current side of the power converter to be in an opening state; according to the technical scheme of the invention, the switching-on control operation can be directly performed on the AC switch on the basis of the switching-off state during the subsequent startup, the state of the AC switch does not need to be detected and distinguished to execute the corresponding switching-on control operation, and the control complexity of the AC switch is also reduced. In addition, the risk caused by long action time of the alternating current switch can be effectively reduced in a power-off and power-reducing mode; in addition, through a fault classification mode, risks caused by short tripping service life of the AC switch can be effectively reduced.

Description

Technical Field

[0001] This application relates to the field of AC switch technology, and in particular to a control device, a computer-readable storage medium, a power converter, and a control method thereof. Background Technology

[0002] On the AC side of a power converter, an AC switch is typically installed to control the connection between the power converter and the external AC system it is connected to. In existing technology, the control logic for AC switches with three operating states—open, trip, and close—is quite complex, and improper control can easily lead to power converter malfunctions. Summary of the Invention

[0003] In view of the above problems, this application provides a control device, a computer-readable storage medium, a power converter, and a control method thereof to reduce the control complexity of AC switches. The specific solution is as follows:

[0004] A first aspect of this application provides a control method for a power converter, applied to a controller in the power converter, wherein an AC switch is provided on the AC side of the power converter; the control method includes:

[0005] After the power converter is powered on, it is initialized and the AC switch is controlled to be in the open state.

[0006] When the power converter is turned on, the AC switch is closed and the power converter is controlled to operate normally.

[0007] When the power converter is turned off, the following operations are performed in sequence: controlling the operating power of the power converter to be less than the preset power, performing the opening control of the AC switch, and performing the power converter to stop transmitting waves.

[0008] In one possible implementation, after closing the AC switch, the method further includes:

[0009] Within a first preset time period, determine whether the AC switch has entered the closed state;

[0010] If it is determined at any time that the AC switch has entered the closed state, then the steps to control the normal operation of the power converter are executed.

[0011] In one possible implementation, after determining whether the AC switch has entered the closed state within a first preset time, the method further includes:

[0012] If it is determined that the AC switch has not entered the closed state within the first preset time period, then the AC switch is first opened, and then the power converter is stopped from transmitting waves and the fault information is reported.

[0013] In one possible implementation, after tripping the AC switch, the method further includes:

[0014] Within a second preset time period, determine whether the AC switch has entered the open state;

[0015] If it is determined at any time that the AC switch has entered the open state, then the step of stopping the power converter from transmitting waves is executed.

[0016] If it is determined that the AC switch has not entered the open state within the second preset time period, then the step of stopping the power converter from generating waves is executed, and fault information is reported.

[0017] In one possible implementation, after controlling the power converter to operate normally, the following is also included:

[0018] When the power converter malfunctions, the AC switch is subjected to a corresponding preset disconnection operation according to the type of malfunction.

[0019] In one possible implementation, the AC switch is subjected to a corresponding preset disconnection operation based on the type of fault, including:

[0020] Determine whether the fault belongs to a preset tripping fault;

[0021] If the fault belongs to the preset trip fault, then the AC switch is tripped.

[0022] If the fault does not belong to the preset trip fault, the AC switch is put into the open state by controlling the power converter to shut down.

[0023] In one possible implementation, after tripping the AC switch, the method further includes:

[0024] The AC switch is tripped and fault information is reported.

[0025] In one possible implementation, controlling the AC switch to be in the open state includes:

[0026] First, a low voltage instruction is sent to the AC switch, and a first time interval is waited; then, a trip instruction is sent to the AC switch, and a second time interval is waited.

[0027] Alternatively, a trip command can be issued to the AC switch, and a second time period can be waited.

[0028] In one possible implementation, closing control of the AC switch is performed, and when it is necessary to subsequently perform a step to determine whether the AC switch has entered the closed state, the following steps are included:

[0029] Send an undervoltage command to the AC switch and wait for a first duration;

[0030] Send a closing command to the AC switch;

[0031] When the closing control of the AC switch does not require subsequent steps to determine whether the AC switch has entered the closed state, the following steps are included:

[0032] Send an undervoltage command to the AC switch and wait for a first duration;

[0033] A closing command is sent to the AC switch, and a third time interval is waited.

[0034] In one possible implementation, after closing the AC switch, opening the AC switch is performed. When it is necessary to perform a subsequent step to determine whether the AC switch has entered the open state, the step includes: issuing an opening command to the AC switch.

[0035] After closing the AC switch, opening the AC switch is performed. When it is not necessary to perform the step of determining whether the AC switch has entered the open state, the following steps are taken: issuing an opening command to the AC switch and waiting for a fourth time period.

[0036] In one possible implementation, tripping control of the AC switch includes:

[0037] An undervoltage command is sent to the AC switch, and the process waits for a fifth time period.

[0038] In one possible implementation, after tripping the AC switch, tripping the AC switch includes:

[0039] First, a low voltage instruction is sent to the AC switch, and a first time interval is waited; then, a trip instruction is sent to the AC switch, and a second time interval is waited.

[0040] Alternatively, a trip command can be issued to the AC switch, and a second time period can be waited.

[0041] In one possible implementation, after tripping the AC switch, the method further includes:

[0042] An undervoltage command is sent to the AC switch.

[0043] A second aspect of this application provides a power converter, including: a main circuit and a controller; wherein,

[0044] An AC switch is connected to the AC side of the main circuit;

[0045] The main circuit is controlled by the controller;

[0046] The controller employs the power converter control method described in the first aspect or any implementation thereof to control the AC switch.

[0047] In one possible implementation, the controller determines the state of the AC switch by detecting the state of the auxiliary contacts in the AC switch.

[0048] In one possible implementation, the AC switch is a molded case circuit breaker.

[0049] A third aspect of this application provides a control device including a processor and a memory, the memory being used to store programs, instructions, or code, and the processor being used to execute the programs, instructions, or code in the memory to perform the control method of the power converter as described in the first aspect or any implementation thereof.

[0050] The fourth aspect of this application provides a computer-readable storage medium storing a computer program that is loaded by a processor to execute the control method of the power converter as described in the first aspect or any implementation thereof.

[0051] Using the above technical solution, the control method for the power converter provided in this application is applied to the controller in the power converter. When executing the control method, the controller first initializes the power converter after power-on; then, it controls the AC switch on the AC side of the power converter to be in the open state. This allows for direct closing control of the AC switch from the open state during subsequent power-on, eliminating the need to detect and distinguish the state of the AC switch before performing the corresponding closing control operation, thus reducing the control complexity of the AC switch. Furthermore, when the power converter is powered off, this embodiment first controls the power converter to operate at reduced power, then controls the AC switch to open, ultimately stopping the power converter from transmitting signals. This avoids the AC side filtering components of the power converter being connected to the power grid for extended periods, thereby preventing resonance and the associated significant risks. Attached Figure Description

[0052] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0053] Figure 1 A flowchart of a control method for a power converter provided in an embodiment of this application;

[0054] Figure 2 Another flowchart of the control method for the power converter provided in the embodiments of this application;

[0055] Figure 3 Another flowchart of the control method for the power converter provided in the embodiments of this application;

[0056] Figure 4 Another flowchart of the control method for the power converter provided in the embodiments of this application;

[0057] Figure 5 A partial flowchart of the power converter control method provided in this application embodiment for power-on initialization;

[0058] Figure 6 A partial flowchart of the power converter control method provided in this application embodiment for the power-on process;

[0059] Figure 7 A partial flowchart of the power converter control method provided in the embodiments of this application for the power-off state;

[0060] Figure 8 A partial flowchart of the control method for a power converter provided in this application embodiment for a fault shutdown;

[0061] Figure 9 This is a schematic diagram of the power converter provided in the embodiments of this application;

[0062] Figure 10 This is a schematic diagram of the structure of a control device provided in this application. Detailed Implementation

[0063] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0064] The embodiments of this application are described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Those skilled in the art will understand that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this application are also applicable to similar technical problems.

[0065] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0066] The AC switch installed on the AC side of the power converter must not only be able to connect, carry, and disconnect normal currents, but also be able to connect, disconnect, and carry abnormal currents, such as short-circuit currents, for a certain period of time.

[0067] There are many types of AC switches that can meet the above requirements, such as mechanical switches like AC circuit breakers, AC relays, and AC contactors, as well as electronic switches implemented by power switching transistors such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and IGBTs (Insulated Gate Bipolar Transistors).

[0068] Taking AC circuit breakers as an example, circuit breakers generally come in two forms: frame circuit breakers and molded case circuit breakers. Currently, the mainstream AC circuit breakers are frame circuit breakers, but frame circuit breakers have the problems of large size and high cost. Molded case circuit breakers, on the other hand, are small in size and low in cost, and have a clear competitive advantage.

[0069] Regarding the control of the two types of circuit breakers, the frame circuit breaker has only two states: closed and open. It is controlled to close when the power converter is turned on and to open when the power converter is turned off or protected. The two states switch back and forth, and the control logic is relatively simple. However, the molded case circuit breaker has three working states: open, tripped, and closed. Among them, the closed and open states can switch between each other, while the tripping state can only be entered from the closed state and can only enter the open state. The control logic is relatively complex.

[0070] In other words, AC switches with three working states—open, trip, and close—have complex control logic, and improper control may lead to power converter failure.

[0071] Therefore, this application provides a control method for a power converter to reduce the control complexity of AC switches. The specific solution is as follows:

[0072] The control method of this power converter is applied to the controller in the power converter. In addition, the AC side of the power converter is provided with an AC switch. Moreover, the AC switch can be set inside or outside the power converter, as long as the AC side of the main circuit inside the power converter can be connected to external AC equipment or external AC power supply through the AC switch. There is no limitation here, and it can be determined according to the specific application environment.

[0073] See Figure 1 The control method includes:

[0074] S101. After the power converter is powered on, perform initialization and control the AC switch to be in the open state.

[0075] When the power converter is powered on, the operating state of its AC switch is unknown. Although the controller can detect the state of the auxiliary contacts in the AC switch, it cannot necessarily determine the complete operating state of the AC switch. Specifically, if the auxiliary contacts are closed, it indicates that the AC switch is in the closed state; while if the auxiliary contacts are open, it indicates that the AC switch is in the tripped or open state. That is, even if the controller can detect the state of the auxiliary contacts, it cannot distinguish between the tripped and open states.

[0076] When the power converter is turned on and the AC switch is closed, if the AC switch is in the open state, it can be directly controlled to enter the closed state; if the AC switch is in the tripped state, it needs to be controlled to enter the open state before it can be controlled to enter the closed state.

[0077] Therefore, in order to avoid distinguishing between the tripped state and the open state and to perform corresponding closing control operations in the future, this embodiment controls the AC switch to be in the open state during the initialization of the power converter.

[0078] Specifically, when controlling the AC switch to be in the open state, if the AC switch is in the tripped state, the control can perform a tripping operation on it, thus putting it into the open state; if the AC switch is in the open state, the control will maintain its open state. By controlling the AC switch to enter or maintain the open state before the power converter is turned on, it can be directly and normally transitioned from the open state to the closed state when the power converter is turned on.

[0079] The control method for the power converter provided in this embodiment, based on the above principle, allows for direct closing control of the AC switch when it is in the open state during subsequent power-on, without the need to detect and distinguish the state of the AC switch and then execute the corresponding closing control operation, thus reducing the control complexity of the AC switch.

[0080] S102. When the power converter is turned on, the AC switch is closed and the power converter is controlled to operate normally.

[0081] The process of closing the AC switch at this point is simply the normal control of the AC switch from the open state to the closed state during power-on, as described in existing technology. The specific process of controlling the normal operation of the power converter can also be found in existing technology and will not be elaborated here.

[0082] S103. When the power converter is powered off, proceed with S301, S302 and S303 in sequence.

[0083] S301, The operating power of the control power converter is less than the preset power.

[0084] S302, Perform tripping control on the AC switch.

[0085] S303, Perform a stop-wave emission control on the power converter.

[0086] That is, when the power converter is turned off, it is first controlled to operate at reduced power. When its operating power is reduced to less than the preset power, the AC switch is controlled to open, and then the power converter is stopped from sending waves, so that the power converter stops operating.

[0087] Because mechanical switches have a long opening time, if the AC switch is opened only after the power converter stops transmitting signals and stops operating, the AC side filtering components of the power converter will remain connected to the external AC equipment or power source on the other side of the AC switch for a relatively long period of time. For example, the capacitors and inductors on the AC side of the power converter may be connected to the power grid, which could lead to resonance and cause significant risks.

[0088] This embodiment first controls the power converter to operate at reduced power, then controls the AC switch to open, and finally stops the power converter from generating signals. This avoids the prolonged connection of the AC side filtering components of the power converter, thereby avoiding the aforementioned resonance risk. In other words, this embodiment effectively reduces the risk caused by the long operating time of the AC switch by shutting down and reducing power.

[0089] In practical applications, the specific value of the preset power can be set according to the power parameters that the AC switch can break. As long as the AC switch can perform a tripping action within its breaking capacity range when S302 is executed after S301, there is no limitation here.

[0090] Based on the previous embodiment, this embodiment provides another control method for a power converter. In step S102, after controlling the closing of the AC switch, it further includes... Figure 2 As shown:

[0091] S201. Within the first preset time period, determine whether the AC switch has entered the closed state.

[0092] In S102, the process of closing the AC switch is as follows: For mechanical switches, since there is a certain closing time, after closing the switch, a period of time can be waited to determine whether the closing was successful.

[0093] To determine whether the AC switch has entered the closed state, the state of its auxiliary contacts can be detected. Specifically, S201 may include: within a first preset time period, determining whether a feedback signal indicating the closure of the auxiliary contact is obtained; if the feedback signal is obtained at any time, it indicates that the AC switch has successfully entered the closed state; if the feedback signal is not obtained, it indicates that the AC switch has failed to successfully enter the closed state.

[0094] In practical applications, the specific value of the first preset duration can be determined according to the actual closing time of the AC switch used. There is no limitation here. It can be adapted to the selection of the AC switch and the electrical parameter specifications of its location. All of these are within the protection scope of this application.

[0095] If it is determined at any time that the AC switch has entered the closed state, the control power converter in S102 can be executed to operate normally.

[0096] In addition, following S201, the AC switch control method may also include Figure 2 As shown: If it is determined that the AC switch has not entered the closed state within the first preset time period, then S202 is executed.

[0097] S202. First, perform the trip control on the AC switch, then perform the stop signal transmission control on the power converter and report the fault information.

[0098] This embodiment addresses the long closing time of mechanical switches by implementing targeted measures in the control logic, thereby improving the reliability of the AC switch. Furthermore, after S201, subsequent steps are selectively executed based on different judgment results. That is, the power converter is only allowed to operate if the AC switch can normally enter the closing state; otherwise, the power converter needs to be stopped from transmitting signals and the fault reported, thus improving the safety of the power converter.

[0099] Based on the above embodiments, see Figure 3 This embodiment provides another control method, in which, after S302, the AC switch is tripped, S103 may further include... Figure 3 (in order to be in) Figure 1 As shown in the example (based on the above):

[0100] S311. Within the second preset time period, determine whether the AC switch has entered the open state.

[0101] To determine whether the AC switch has entered the open state, the state of its auxiliary contacts can be detected. Specifically, S311 may include: within a second preset time period, determining whether a feedback signal indicating that the auxiliary contact is open is obtained; if the feedback signal is obtained at any time, it means that the AC switch has successfully entered the open state; if the feedback signal is not obtained, it means that the AC switch has failed to successfully enter the open state.

[0102] In practical applications, the specific value of the second preset duration can be determined according to the actual opening time of the AC switch used. There is no limitation here. It can be adapted to the selection of the AC switch and the electrical parameter specifications of its location. All of these are within the protection scope of this application.

[0103] Furthermore, after executing S311, if it is determined at any time that the AC switch has entered the open state, then S303 can be executed, which is to stop the power converter from generating waves. If it is determined that the AC switch has not entered the open state within the second preset time period, then S304 can be executed simultaneously with or before executing S303.

[0104] S304, Report fault information.

[0105] The fault information here indicates a fault in the AC switch and can provide specific guidance for subsequent maintenance work.

[0106] Through the above S311, corresponding control logic processing can be provided to address the problem of long opening time of mechanical switches, thereby improving the reliability of the AC switch; furthermore, it can also detect whether the AC switch can open normally while ensuring the safe shutdown of the power converter, and provide timely fault prompts when it cannot open normally.

[0107] Based on the above embodiments, see Figure 4 (in order to be in) Figure 1 (Taking the example below), this embodiment provides another control method, which, after controlling the power converter to operate normally in S102, further includes:

[0108] S400. When a fault occurs in the power converter, the AC switch is operated according to the corresponding preset disconnection operation based on the type of fault.

[0109] Because the AC switch has a limited tripping life, if the power converter trips the AC switch directly whenever it encounters any fault, it may cause the AC switch to be damaged within the lifespan of the power converter. Therefore, this embodiment classifies the faults of the power converter and determines whether to perform a tripping operation based on the type of fault that has occurred.

[0110] In this S400, based on the type of fault, a corresponding preset disconnection operation is performed on the AC switch, which may specifically include... Figure 4 As shown:

[0111] S401. Determine whether the fault belongs to the preset trip fault.

[0112] In one example, when classifying faults of the power converter, only faults that may cause damage to the power converter may be recorded as belonging to the preset trip fault, while other faults that will not cause damage to the power converter may not be recorded as belonging to the preset trip fault.

[0113] After executing S401, if the fault is a preset trip fault, then execute S402. If the fault is not a preset trip fault, then execute S403.

[0114] S402, Trip control of AC switch.

[0115] S403. By controlling the power converter to shut down, the AC switch is put into the open state.

[0116] The process of controlling the power converter to shut down can be found in the above embodiments, and will not be repeated here.

[0117] In other words, in this embodiment, the controller only trips the AC switch for faults that could damage the power converter, ensuring timely disconnection of the power converter from external AC equipment or power sources connected to its AC side. For example, it quickly disconnects the power converter from its connection to the power grid, thus protecting the power converter. For faults that will not damage the power converter, the controller can issue a trip command to the AC switch. In this case, even if the shutdown time is long, it will not cause damage to the power converter. Therefore, the number of trips of the AC switch can be reduced, extending the time it takes for the AC switch to reach its trip lifespan and improving its reliability.

[0118] In other words, this embodiment can effectively reduce the risks caused by the short tripping life of AC switches by using a fault classification method.

[0119] In addition, after executing S402, the control method may also include Figure 4 As shown:

[0120] S404. Perform tripping control on the AC switch and report fault information.

[0121] By executing S403, the AC switch can be placed in the open state, ensuring that it can be closed normally the next time it is controlled. Furthermore, by reporting this fault information, maintenance personnel can obtain specific details of the current fault in the power converter, providing a reference for maintenance.

[0122] As described in the above embodiments, the AC switch can be implemented in various forms. This embodiment, based on the above embodiments, takes the undervoltage release device in the AC switch as an example and provides a detailed description of several control processes in the control method, such as:

[0123] In one example, in S101, controlling the AC switch to be in the open state can specifically include: sending an undervoltage relief command to the AC switch and waiting for a first duration; and sending an open command to the AC switch and waiting for a second duration.

[0124] The first and second durations here are for waiting for the mechanical switch to respond to the corresponding command. The values ​​of the two durations can be determined according to the specific selection of the AC switch, and are not limited here.

[0125] In practical applications, depending on the specific design of the AC switch, some models of AC switches may not require issuing the aforementioned undervoltage release command when controlling their tripping. That is, in S101, controlling the AC switch to be in the tripping state may only include: issuing a tripping command to the AC switch and waiting for a second duration. The specific control process can be determined according to the actual selection of the AC switch, and is not limited here, but is all within the protection scope of this application.

[0126] In addition, after issuing a trip command to the AC switch and waiting for a second period of time, an undervoltage command can be further issued to the AC switch to prevent the AC switch from being accidentally closed.

[0127] In practical applications, any command sent to this AC switch can continuously send corresponding signals for a certain duration, with no specific time limit. For details regarding the control process of the AC switch during power-on initialization of the power converter, please refer to [link to relevant documentation]. Figure 5 That is, after the power converter is powered on, it first continuously sends an undervoltage signal for a certain duration t1 and waits for the first duration t1'; then, it continuously sends a trip signal for a certain duration t2 and waits for the second duration t2'; then, it continuously sends an undervoltage signal for a certain duration t3, which can cause the AC switch to enter the trip state; at this time, the power converter enters the standby state and waits to receive the power-on command.

[0128] In one example, the closing control of the AC switch in S102 may specifically include: sending an undervoltage relief command to the AC switch and waiting for a first duration; and sending a closing command to the AC switch and waiting for a third duration.

[0129] The setting of this third duration is to wait for the mechanical switch to respond to the closing command, and its value is not limited.

[0130] Similar to the example above, the closing command can also be issued continuously for a certain period of time, the specific duration of which is not limited, such as several hundred milliseconds; in practical applications, the form of the closing signal is not limited, such as it can be a square wave.

[0131] In practical applications, if a subsequent step is required to determine whether the AC switch has entered the closed state, i.e., to execute the aforementioned S201, then in the step of controlling the closing of the AC switch, after issuing the closing command to the AC switch, the third time interval can be omitted. Specifically, this is because the existence of the first preset time interval in S201 can replace this waiting process. Moreover, the values ​​of the third time interval and the first preset time interval can be equal or unequal, depending on the specific application environment, and are not limited here.

[0132] In addition, in the above embodiment, after the AC switch is tripped, S202 can first send an undervoltage command to the AC switch, then stop the power converter from transmitting waves and report the fault information.

[0133] When the power converter is powered on, the controller's control logic for this AC switch can be found in [reference needed]. Figure 6 When a power-on command is received, the controller first needs to continuously send an undervoltage signal for a certain duration t4 and wait for the first duration t4'. Then, it continuously sends a closing signal for a certain duration t5. Next, it checks the status of the auxiliary contacts. If the auxiliary contacts are closed, it means that the closing action is completed and the power converter can operate normally. If the auxiliary contacts are open for the first preset duration t6, it means that the closing action has failed. In this case, it can continuously send a tripping signal for a certain duration t7 and wait for the second duration t7'. Then, it continuously sends an undervoltage signal for a certain duration t8, stops the power converter from transmitting waves, and reports the corresponding fault information.

[0134] In one example, the process of controlling the AC switch to open after closing the AC switch, i.e., S302, may specifically include: issuing an opening command to the AC switch and waiting for a fourth time period.

[0135] In practical applications, when it is necessary to perform the step of determining whether the AC switch has entered the open state, that is, when it is necessary to execute the above-mentioned S311, during the process of controlling the AC switch to open, after issuing the open command to the AC switch, it is not necessary to wait for the fourth time period. Specifically, this is because the existence of the second preset time period in S311 can replace this waiting process. Moreover, the values ​​of the fourth time period and the second preset time period can be equal or unequal, depending on the specific application environment, and are not limited here.

[0136] In addition, after S311 and before S303 and S304, an undervoltage command can also be issued to the AC switch to prevent the AC switch from being closed accidentally.

[0137] When the power converter is powered off, the controller's control logic for the AC switch can be found in [reference needed]. Figure 7 When a shutdown command is received, to avoid resonance risk, the power converter is first reduced to a preset power, and then continues to transmit waves and continuously sends a trip signal for a certain duration t9, causing the AC switch to trip. Then, the status of its auxiliary contacts is checked. If the auxiliary contacts are normally open, an undervoltage signal is continuously sent for a certain duration t10, and then the transmission stops, and the power converter shuts down normally. If the auxiliary contacts remain open for a second preset duration t11, an undervoltage signal is continuously sent for a certain duration t12, then the transmission stops, and fault information of AC switch node abnormality is reported.

[0138] In one example, S402 in the above embodiment, which controls the tripping of the AC switch, may specifically include: sending an undervoltage command to the AC switch and waiting for a fifth duration.

[0139] Furthermore, after tripping the AC switch, the AC switch is then tripped, i.e., tripping the AC switch in S404 of the above embodiment. This can specifically include: first, issuing an undervoltage release command to the AC switch and waiting for a first duration; then, issuing a tripping command to the AC switch and waiting for a second duration. Alternatively, the tripping control in S404 can simply include: issuing a tripping command to the AC switch and waiting for a second duration. This depends on the specific model of the AC switch used, and all are within the scope of protection of this application.

[0140] Similar to the above, after S403, the control method may also include: issuing an undervoltage command to the AC switch.

[0141] When the power converter fails and shuts down, the controller's control logic for the AC switch can be found in [reference needed]. Figure 8 To extend the tripping life of the AC switch and prevent its damage during the power converter's lifespan, the following procedures are followed if a fault occurs during normal operation of the power converter: For faults that may damage the power converter, an undervoltage signal is continuously sent for a certain duration t13, and the process waits for a fifth duration t13' to put the AC switch into the tripping state; then, an undervoltage signal is continuously sent for a certain duration t14, and the process waits for a first duration t14' to allow for a tripping operation; then, a tripping signal is continuously sent for a certain duration t15, and the process waits for a second duration t15'; finally, an undervoltage signal is continuously sent for a certain duration t16, and fault information is reported. For faults that will not damage the power converter, the following steps can be performed: Figure 7 The control logic during shutdown shown in the diagram will not be elaborated here.

[0142] Another embodiment of this application also provides a power converter, such as Figure 9 As shown, it includes: a main circuit 10 and a controller 20; wherein:

[0143] An AC switch 30 is connected to the AC side of the main circuit 10. In practical applications, the location of the AC switch 30 is not limited. It can be located inside the power converter, that is, on the AC side of the main circuit 10, connected to the AC side of the power converter via the AC switch 30. The AC side of the power converter is used to connect external AC equipment or an external AC power source. The external AC power source can refer to the power grid, but is not limited to this. Alternatively, the AC switch 30 can be located outside the power converter, meaning that the AC side of the main circuit 10 can be connected to one side of the AC switch 30 via the AC side of the power converter, and the other side of the AC switch 30 can be connected to the aforementioned external AC equipment or external AC power source. The choice depends on the specific application environment and is within the scope of this application.

[0144] The other side of the main circuit 10 is connected to the other side of the power converter. In practical applications, the main circuit 10 can be a DC / AC conversion circuit or an AC / AC conversion circuit. That is, one side of the main circuit 10 is the AC side, and the other side can be the DC side or the AC side, depending on the specific application environment, all of which are within the protection scope of this application. Depending on the specific structure of the main circuit 10, the power converter can be applied to different application scenarios. For example, when the main circuit 10 is a DC / AC conversion circuit, the power converter can be used as a photovoltaic inverter or an energy storage converter, etc.; when the main circuit 10 is an AC / AC conversion circuit, the power converter can be used as a wind turbine, etc., depending on the specific application environment. These are just some optional examples and are not limited to them.

[0145] The main circuit 10 is controlled by the controller 20; moreover, the controller 20 employs the power converter control method described in any of the above embodiments to control the AC switch 30. The specific process and principle of this control method can be found in the above embodiments, and will not be repeated here.

[0146] In practical applications, the controller 20 can determine the state of the AC switch 30 by detecting the state of the auxiliary contacts in the AC switch 30. The specific detection and determination process can be found in the above embodiments, and will not be repeated here.

[0147] Furthermore, as described in the above embodiments, the AC switch 30 can be implemented in various forms. For example, it can be implemented using a molded case circuit breaker. By executing the above control method, based on the small size and low cost of the molded case circuit breaker, it can control it with simple logic for various operating conditions such as initial power-on, power-on, power-off, and fault shutdown, thereby reducing the complexity of the control logic. Moreover, by reducing power during power-off, the risk caused by the long operating time of the molded case circuit breaker can be effectively reduced. In addition, by classifying faults, the risk caused by the short tripping life of the molded case circuit breaker can also be effectively reduced.

[0148] Another embodiment of this application also provides a control device, such as... Figure 10 As shown, the control device may include a memory 101 and a processor 102. The processor 102 may be connected to the power converter and may control the main circuit 10 and AC switch 30 in the power converter.

[0149] The memory 101 can specifically be RAM (random access memory), flash memory, ROM (read only memory), EPROM (Electronic Programmable ROM, a type of non-volatile read-only memory), registers, hard disks, removable disks, etc.

[0150] The memory 101 is used to store computer instructions. When the computer instructions stored in the memory 101 are executed by the processor 102, the processor 102 can be used to execute the control method of the power converter described in any of the above embodiments. The memory 101 can also store data, such as various duration information involved in the above embodiments.

[0151] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, DSL (digital subscriber line)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media, such as floppy disks, hard disks, and magnetic tapes; or, the available media can be semiconductor media, such as SSDs (solid-state disks); the available media can also be other media, without limitation.

[0152] Another embodiment of this application provides a computer-readable storage medium storing a computer program that is loaded by a processor to execute the control method of the power converter as described in any of the above embodiments.

[0153] That is, the computer-readable storage medium is used to store the methods or algorithms provided in the above embodiments. Specifically, it can be RAM, flash memory, ROM, EPROM, registers, hard disk, removable disk, or any other form of storage medium in the art.

[0154] Similar or identical parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0155] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0156] The features described above regarding the disclosed embodiments can be substituted for or combined with each other to enable those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a power converter, characterized in that, A controller applied in the power converter, wherein an AC switch is provided on the AC side of the power converter; the control method includes: After the power converter is powered on, it is initialized and the AC switch is controlled to be in the open state. When the power converter is turned on, the AC switch is closed and the power converter is controlled to operate normally. When the power converter is turned off, the following operations are performed in sequence: controlling the operating power of the power converter to be less than the preset power, performing the opening control of the AC switch, and performing the power converter to stop transmitting waves.

2. The control method for the power converter according to claim 1, characterized in that, After closing the AC switch, the following steps are also included: Within a first preset time period, determine whether the AC switch has entered the closed state; If it is determined at any time that the AC switch has entered the closed state, then the steps to control the normal operation of the power converter are executed.

3. The control method for the power converter according to claim 2, characterized in that, After determining whether the AC switch has entered the closed state within the first preset time, the method further includes: If it is determined that the AC switch has not entered the closed state within the first preset time period, then the AC switch is first opened, and then the power converter is stopped from transmitting waves and the fault information is reported.

4. The control method for the power converter according to claim 1, characterized in that, After the AC switch is tripped, the following steps are also included: Within a second preset time period, determine whether the AC switch has entered the open state; If it is determined at any time that the AC switch has entered the open state, then the step of stopping the power converter from transmitting waves is executed. If it is determined that the AC switch has not entered the open state within the second preset time period, then the step of stopping the power converter from generating waves is executed, and fault information is reported.

5. The control method for the power converter according to claim 1, characterized in that, After controlling the power converter to operate normally, the following is also included: When the power converter malfunctions, the AC switch is subjected to a corresponding preset disconnection operation according to the type of malfunction.

6. The control method for the power converter according to claim 5, characterized in that, Based on the type of fault, the AC switch is subjected to a corresponding preset disconnection operation, including: Determine whether the fault belongs to a preset tripping fault; If the fault belongs to the preset trip fault, then the AC switch is tripped. If the fault does not belong to the preset trip fault, the AC switch is put into the open state by controlling the power converter to shut down.

7. The control method for the power converter according to claim 6, characterized in that, After tripping the AC switch, the following steps are also included: The AC switch is tripped and fault information is reported.

8. The control method for the power converter according to any one of claims 1 to 7, characterized in that, Controlling the AC switch to be in the open state includes: First, a low voltage instruction is sent to the AC switch, and a first time interval is waited; then, a trip instruction is sent to the AC switch, and a second time interval is waited. Alternatively, a trip command can be issued to the AC switch, and a second time period can be waited.

9. The control method for the power converter according to any one of claims 1 to 7, characterized in that, The closing control of the AC switch, when it is necessary to perform a subsequent step of determining whether the AC switch has entered the closed state, includes: Send an undervoltage command to the AC switch and wait for a first duration; Send a closing command to the AC switch; When the closing control of the AC switch does not require subsequent steps to determine whether the AC switch has entered the closed state, the following steps are included: Send an undervoltage command to the AC switch and wait for a first duration; A closing command is sent to the AC switch, and a third time interval is waited.

10. The control method for the power converter according to any one of claims 1 to 7, characterized in that, After closing the AC switch, opening the AC switch is performed. When it is necessary to determine whether the AC switch has entered the open state in the subsequent steps, the following steps are taken: issuing an opening command to the AC switch. After closing the AC switch, opening the AC switch is performed. When it is not necessary to perform the step of determining whether the AC switch has entered the open state, the following steps are taken: issuing an opening command to the AC switch and waiting for a fourth time period.

11. The control method for the power converter according to claim 6 or 7, characterized in that, The tripping control of the AC switch includes: An undervoltage command is sent to the AC switch, and the process waits for a fifth time period.

12. The control method for the power converter according to claim 7, characterized in that, After tripping the AC switch, the AC switch is then tripped, including: First, a low voltage instruction is sent to the AC switch, and a first time interval is waited; then, a trip instruction is sent to the AC switch, and a second time interval is waited. Alternatively, a trip command can be issued to the AC switch, and a second time period can be waited.

13. The control method for the power converter according to any one of claims 1 to 7, characterized in that, After the AC switch is tripped, the following steps are also included: An undervoltage command is sent to the AC switch.

14. A power converter, characterized in that, include: Main circuit and controller; among which, An AC switch is connected to the AC side of the main circuit; The main circuit is controlled by the controller; The controller employs the control method for the power converter as described in any one of claims 1 to 13 to control the AC switch.

15. The power converter according to claim 14, characterized in that, The controller determines the state of the AC switch by detecting the state of the auxiliary contacts in the AC switch.

16. The power converter according to claim 14 or 15, characterized in that, The AC switch is a molded case circuit breaker.

17. A control device, characterized in that, It includes a processor and a memory, the memory being used to store programs, instructions, or code, and the processor being used to execute the programs, instructions, or code in the memory to perform the control method of the power converter as described in any one of claims 1 to 13.

18. A computer-readable storage medium, characterized in that, The device contains a computer program that is loaded by a processor to execute the control method for the power converter as described in any one of claims 1 to 13.

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