Converter control method, controller and readable storage medium

Abstract

The invention provides a converter control method, a controller and a readable storage medium. The control method comprises the following steps: generating a local event every first time interval according to a local clock of the converter; loading a carrier in response to the fact that the generation of the local event reaches the preset duration; generating a PWM signal for controlling the converter based on the loaded carrier wave; dynamically updating the length of the first time interval according to a distributed clock so as to realize carrier phase shift between the converter and other converters in the new energy station; wherein the distributed clocks used by all converters in the new energy station are synchronized.

Description

Technical Field

[0001] The present disclosure generally relates to the field of power electronics technology, and more specifically, to a control method, a controller and a readable storage medium of a converter. Background Art

[0002] In large-scale grid-connected systems of new energy, the diversified access of wind power, photovoltaic power, and energy storage cannot be separated from high-power power electronic converters. When they are operated in parallel, the currents flow to each other due to the inconsistency of circuit parameters and control, which brings about circulation problems. The circulation between parallel modules will affect the normal operation of the entire system. On the one hand, it may cause the output current of the module to be distorted, and in severe cases it may exceed the tolerance range of the device, causing the entire system to collapse; on the other hand, excessive circulation will greatly increase the power loss of the system, causing serious heating of the system, which will reduce work efficiency and bring safety hazards.

[0003] In fact, the parallel system of power electronic converters is relatively complex. Existing research focuses on analyzing low-frequency circulating currents such as power frequency, DC and harmonic circulating currents, and ignores the high-frequency circulating currents of the system. Since it is difficult for the carriers of the parallel modules of power electronic converters to remain consistent, high-frequency circulating currents are inevitably introduced. Commonly used methods to suppress high-frequency circulating currents are through LCL filtering, designing appropriate hardware circuits, etc., but this undoubtedly increases the hardware cost of circuit design difficulty. Summary of the invention

[0004] An exemplary embodiment of the present disclosure provides a control method, a controller and a readable storage medium of a converter, which can effectively suppress the high-frequency circulating current problem of a parallel system of power electronic converters without the need for additional hardware equipment.

[0005] According to a first aspect of an embodiment of the present disclosure, a control method for a converter is provided, the control method comprising: generating a local event at a first time interval according to a local clock of the converter; loading a carrier in response to the local event generation reaching a preset duration; generating a PWM signal for controlling the converter based on the loaded carrier; dynamically updating the length of the first time interval according to a distributed clock to achieve carrier phase shifting between the converter and other converters in a new energy station; wherein the distributed clocks used by all converters in the new energy station are synchronized.

[0006] Optionally, the step of dynamically updating the length of the first time interval according to the distributed clock includes: generating a synchronization event every second time interval according to the distributed clock; dynamically updating the length of the first time interval so that the time interval between the local event and the synchronization event reaches a target value; wherein the target value is determined based on the phase shift angle and the period of the carrier.

[0007] Optionally, the step of dynamically updating the length of the first time interval so that the time interval between the local event and the synchronization event reaches the target value includes: based on the generation time of the most recent synchronization event and the target value, processing the length of the first time interval, wherein the processing is one of increasing, decreasing, and keeping unchanged.

[0008] Optionally, according to the local clock of the converter, the step of generating a local event every first time interval includes: according to the local clock, starting clock beat counting from the clock beat counting starting point, generating a local event and restarting the clock beat counting when the clock beat counting end point is reached; wherein the difference between the clock beat counting end point and the clock beat counting starting point is: the ratio of the current length of the first time interval to the single clock beat time of the local clock.

[0009] Optionally, the step of dynamically updating the length of the first time interval so that the time interval between the local event and the synchronization event reaches the target value includes: determining a specific count value counted by the clock beat count at the moment when the most recent synchronization event occurs; and processing the length of the first time interval based on the clock beat count starting point, the clock beat count end point, the specific count value and the target value.

[0010] Optionally, the phase shift angle is 0 degrees; wherein, based on the clock beat count starting point, the clock beat count end point, the specific count value and the target value, the step of processing the length of the first time interval includes: in response to the specific count value being less than the clock beat count end point and greater than the clock beat count midpoint, shortening the length of the first time interval; in response to the specific count value being less than or equal to the clock beat count midpoint, increasing the length of the first time interval; in response to the specific count value being equal to the clock beat count end point, keeping the length of the first time interval unchanged; wherein, the clock beat count midpoint is the midpoint between the clock beat count starting point and the clock beat count end point.

[0011] Optionally, the phase shift angle is not 0 degrees; wherein, based on the clock beat counting starting point, the clock beat counting end point, the specific count value and the target value, the step of processing the length of the first time interval includes: in response to the sum of the number of clock beats corresponding to the target value and the specific count value being not greater than the clock beat counting end point, and the sum being less than the clock beat counting end point and greater than the clock beat counting midpoint, shortening the length of the first time interval; in response to the sum being not greater than the clock beat counting midpoint, increasing the length of the first time interval; in response to the sum being equal to the clock beat counting end point, keeping the length of the first time interval unchanged; wherein the clock beat counting midpoint is the midpoint between the clock beat counting starting point and the clock beat counting end point; wherein the number of clock beats corresponding to the target value is the ratio of the target value to a single clock beat time of the local clock.

[0012] Optionally, the phase shift angle is not 0 degrees; wherein, based on the clock beat counting starting point, the clock beat counting end point, the specific count value and the target value, the step of processing the length of the first time interval also includes: in response to the sum of the number of clock beats corresponding to the target value and the specific count value being greater than the clock beat counting end point, and the difference between the sum and the clock beat counting end point being less than the clock beat counting end point and greater than the clock beat counting midpoint, shortening the length of the first time interval; in response to the sum being greater than the clock beat counting end point, and the difference being not greater than the clock beat counting midpoint, increasing the length of the first time interval; in response to the sum being greater than the clock beat counting end point, and the difference being equal to the clock beat counting end point, keeping the length of the first time interval unchanged; wherein the clock beat counting midpoint is the midpoint between the clock beat counting starting point and the clock beat counting end point; wherein the clock beat counting number corresponding to the target value is the ratio of the target value to a single clock beat time of the local clock.

[0013] Optionally, the step of increasing the length of the first time interval includes: updating the clock beat count starting point m to mj, and keeping the clock beat count end point unchanged; wherein, the step of shortening the length of the first time interval includes: updating the clock beat count starting point m to m+j, and keeping the clock beat count end point unchanged; wherein, j is a preset adjustment step.

[0014] Optionally, the carrier is a triangular carrier; and / or, the initial value of the first time interval is the period of the carrier; and / or, the second time interval is the period of the carrier.

[0015] According to a second aspect of an embodiment of the present disclosure, there is provided a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the control method of the converter as described above.

[0016] According to a third aspect of an embodiment of the present disclosure, a controller of a converter is provided, the controller comprising: a processor; and a memory storing a computer program, which, when executed by the processor, prompts the processor to execute the control method of the converter as described above.

[0017] According to the control method, controller and readable storage medium of the converter of the exemplary embodiment of the present disclosure, an adaptive and inductive carrier phase shifting method is proposed, which can realize carrier phase shifting at any angle under any state between distributed power electronic converters in new energy stations, and can effectively suppress the high-frequency circulating current problem of the parallel system of power electronic converters without the need for additional hardware equipment.

[0018] In the following description, some aspects and / or advantages of the general inventive concept will be set forth, and some other aspects and / or advantages will be known through the following description or the implementation of the general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] These and / or other aspects and advantages of the present application will become clearer and easier to understand from the following detailed description of the embodiments of the present application in conjunction with the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram showing a connection mode of a power electronic converter of a new energy station according to an exemplary embodiment of the present disclosure;

[0021] Figure 2 A flow chart showing a control method of a converter according to an exemplary embodiment of the present disclosure;

[0022] Figure 3 A flowchart showing a method of processing the length of a first time interval according to a first exemplary embodiment of the present disclosure;

[0023] Figure 4 A flowchart showing a method of processing the length of a first time interval according to a second exemplary embodiment of the present disclosure;

[0024] Figure 5 A flowchart showing a method of processing the length of a first time interval according to a third exemplary embodiment of the present disclosure;

[0025] Figure 6 A schematic diagram showing a high-speed synchronous control system platform according to an exemplary embodiment of the present disclosure;

[0026] Figure 7 A schematic diagram showing a substation operation mechanism according to an exemplary embodiment of the present disclosure;

[0027] Figure 8 A schematic diagram showing a substation carrier synchronization operation according to an exemplary embodiment of the present disclosure;

[0028] Fig. 9 An example of grid-connected current value of existing parallel non-synchronous converters is shown;

[0029] Fig.10 An example of a grid-connected current value of parallel synchronously operated converters according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0030] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like parts throughout. The embodiments will be described below with reference to the drawings in order to explain the present disclosure.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0032] It should be noted that the phrase "at least one of the items" in the present disclosure includes three types of parallel situations: "any one of the items", "a combination of any number of the items", and "all of the items". For example, "including at least one of A and B" includes the following three parallel situations: (1) including A; (2) including B; (3) including A and B. Another example is "executing at least one of step 1 and step 2" which means the following three parallel situations: (1) executing step 1; (2) executing step 2; (3) executing step 1 and step 2.

[0033] Figure 1 A schematic diagram showing a connection method of a power electronic converter of a new energy station according to an exemplary embodiment of the present disclosure is shown.

[0034] Reference Figure 1There are multiple parallel lines in the new energy station, and each line is connected to multiple power electronic converters (hereinafter referred to as converters). One side of each converter is connected to the substation of the new energy station via the corresponding transformer, and the other side is connected to the corresponding power supply equipment.

[0035] As an example, the type of power electronic converter may include but is not limited to at least one of the following items: a converter, an inverter, and a frequency converter. It should be understood that other types may also be included, and the present disclosure is not limited thereto.

[0036] As an example, the type of power supply equipment connected to the power electronic converter may include but is not limited to at least one of the following items: a wind turbine, a photovoltaic component, and an energy storage device. It should be understood that other types may also be included and the present disclosure does not limit this.

[0037] Figure 2 A flow chart showing a control method of a converter according to an exemplary embodiment of the present disclosure is shown. As an example, the control method of a converter according to an exemplary embodiment of the present disclosure may be performed by a controller of the converter.

[0038] Reference Figure 2 In step S101, a local event is generated every first time interval according to the local clock of the converter.

[0039] The local clock of the converter is the clock system of the controller of the converter itself. The local clock is based on the crystal oscillator clock count of the controller itself, and is hereinafter referred to as the LC clock.

[0040] In step S102, if the local event generation reaches the preset duration δ t , then load the carrier.

[0041] In other words, the time interval between the carrier loading time and the local event generation time is a preset time δ t , whenever a local event reaches the preset duration δ t , then the carrier is loaded. t is a fixed value, that is, the carrier loading time is based on the LC clock.

[0042] As an example, the type of carrier may include but is not limited to a triangular carrier, and the specific implementation depends on actual needs.

[0043] As an example, the initial value of the first time interval may be a period of the carrier.

[0044] In step S103 , a PWM signal for controlling the converter is generated based on the loaded carrier.

[0045] As an example, a PWM signal for controlling a three-phase power module in the converter can be generated based on the loaded carrier and the three-phase modulation wave corresponding to the converter. The three-phase power module can also be called a three-level bridge arm, a three-level topology, or an IGBT module. As an example, each three-phase power module may include a plurality of switch tubes (IGBTs) and diodes connected in reverse parallel thereto.

[0046] In step S104, the length of the first time interval is dynamically updated according to the distributed clock to achieve carrier phase shifting between the converter and other converters in the new energy station.

[0047] The clock mechanism of the power electronic converter in the new energy station means that each power electronic converter has two clock systems, a local clock system and a synchronous clock system (i.e., a distributed clock system), and the distributed clocks used by all converters in the new energy station are synchronized. As an example, each power electronic converter (i.e., substation) in the station has a distributed clock (DC) timing mechanism, and the distributed clocks of all substation SLAVERs can be synchronized with the master station DC-MASTER reference clock (e.g., the local clock of the field control) to achieve the distributed clock synchronization used by all converters in the station. The distributed clock of each converter relies on the underlying communication and computing capabilities of the controller to provide a high-precision clock synchronized with the master station, hereinafter referred to as the DC clock.

[0048] Figure 6 A schematic diagram of a high-speed synchronous control system platform according to an exemplary embodiment of the present disclosure is shown. The control method of the converter according to the exemplary embodiment of the present disclosure can be implemented based on the high-speed synchronous control system platform. Substation 1 is connected to the main station through optical fiber communication, substation 2 is connected to substation 1 through optical fiber communication, substation 3 is connected to substation 2 through optical fiber communication, and so on. Through the high-speed synchronous control system platform, the distributed clock synchronization used by all converters in the new energy station can be effectively realized. It should be understood that the high-speed synchronous control system platform architecture used can also adopt other forms, and the present disclosure does not limit this.

[0049] The same carrier loading time between substations can achieve the same carrier phase between substations. The carrier loading time between substations is separated by a certain time (the time is related to the phase shift angle), so that the carrier phase between substations differs by the phase shift angle.

[0050] As an example, step S104 may include: generating a synchronization event every second time interval according to the distributed clock; and dynamically updating the length of the first time interval so that the time interval between the local event and the synchronization event reaches a target value. The target value is determined based on the phase shift angle and the period of the carrier.

[0051] As an example, the second time interval may be a period of the carrier wave.

[0052] like Figure 7 As shown, δ t1 , δ t2 , δ tk Respectively represent the time interval between the local event and the synchronous event of substation 1, substation 2, and substation K; δ t11 , δ t12 , δ t1k They represent the time interval between the triangle carrier loading moment and the synchronization event of substation 1, substation 2, and substation K. Since the local LC clock and DC clock have different time bases, δ t1 , δ t2 , δ tk , δ t11 , δ t12 , δ t1k is the amount that drifts over time. But there exists:

[0053] δ t1k =δ t +δ tk (d-1)

[0054] From formula d-1, we can see that δ t is a constant value, and the loading time (phase) of the triangular carrier is determined by the time interval δ between the local event and the synchronous event. tk Decide, therefore, to change δ tk This can achieve a carrier phase shift of 0 to 2π between substations.

[0055] Specifically, if the length of the first time interval is changed, the time when the local event occurs will change, and the carrier loading time will also change accordingly. Therefore, the length of the first time interval can be dynamically updated to make the time interval between the local event and the synchronization event reach the target value, so as to achieve precise adjustment of the carrier loading time and realize a carrier phase shift of 0 to 2π between substations.

[0056] As an example, the target value could be Among them, T sRepresents the period of the carrier, θ is determined based on the phase shift angle and is pre-allocated according to the carrier phase shift demand (for example, θ can be scheduled and allocated by the station controller). For example, if the carrier phase shift angle between substations is 0 (that is, the carriers between substations are synchronized), then θ=0; if the carrier phase shift angle between substations is not 0 (that is, the phases of the carriers corresponding to each substation differ by a certain angle ω in sequence), for example, the carrier phase difference between substation 2 and substation 1 is ω, the carrier phase difference between substation 3 and substation 2 is ω, and so on, accordingly, substation 1 can be used as a reference, and its corresponding θ=0; substation 2 corresponds to θ=ω, so as to achieve a carrier phase difference of ω between substation 2 and substation 1; substation 3 corresponds to θ=2ω, so as to achieve a carrier phase difference of ω between substation 3 and substation 2.

[0057] Since each converter (i.e., each substation) within the new energy station executes the converter control method according to the exemplary embodiment of the present disclosure, all converters can adjust the local carrier loading time (phase) according to the synchronized distributed clock, thereby achieving a carrier phase shift of 0 to 2π between converters.

[0058] As an example, the step of dynamically updating the length of the first time interval so that the time interval between the local event and the synchronization event reaches the target value may include: periodically processing the length of the first time interval based on the time when the most recent synchronization event is generated and the target value, wherein the above-mentioned "processing" refers to one of increasing, decreasing, and keeping unchanged. In other words, whenever a synchronization event is generated, the length of the first time interval is processed based on the time when the synchronization event is generated and the target value.

[0059] As an example, step S101 may include: starting clock beat counting from the clock beat counting starting point according to the local clock, generating a local event and restarting the clock beat counting when the clock beat counting end point is reached. The difference between the clock beat counting end point and the clock beat counting starting point is: the ratio of the current length of the first time interval to the single clock beat time of the local clock. Accordingly, step S104 may include: step S1041 and step S1042. In step S1041, determine the specific count value counted by the above clock beat counting at the time of generation of the most recent synchronization event; in step S1042, based on the clock beat counting starting point, the clock beat counting end point, the specific count value and the target value, process the length of the first time interval.

[0060] The present disclosure considers that: assuming that there is δ t1 =δ t2 =δ tk =δ, such as Figure 8 As shown, then δ t11 =δ t12 =δ t1k, the time intervals between the triangular carrier waves and the synchronization events of each sub-station are the same, and the phase-shifted angle is 0π, that is, the carrier waves of each sub-station operate synchronously. To achieve δ t1 =δ t2 =δ tk =δ, let the crystal oscillator clock counting beat time of the sub-station controller (i.e., the single clock beat time of the local clock of the sub-station) be Δ t , then there is,

[0061]

[0062] N represents the number of count values in one cycle (the cycle is T s ) of the local event. Let the cycle counting starting point (i.e., the initial count value) be m, the end point be n. After each count value reaches n, a local event is generated, and the count value returns to the counting starting point again. When the synchronization event is triggered, record the count value N1 of the local event. If

[0063]

[0064] Then the next cycle counting starting point of the local event is adjusted to m + j, where j is the adjustment step. For example, 0 < j ≤ m. Thus, when the synchronization event is triggered again, the count value of the local event changes from N1 to N1 + j, approaching the count value n step by step in the positive direction; if

[0065]

[0066] Then the next cycle counting starting point of the local event is adjusted to m - j. Thus, when the synchronization event is triggered again, the count value of the local event changes from N1 to N1 - j, approaching the count value n in the reverse direction; if

[0067] N1 = n(e - 4)

[0068] Then the next cycle counting starting point of the local event remains m. Through real-time dynamic adjustment, N1 → n is achieved. At this time, the time interval δ between the local event and the synchronization event → Δ t , usually the unit of Δ t is in the nanosecond level, then it can be considered that δ t11 =δ t12 =δ t1k , and the carrier waves of each sub-station operate synchronously.

[0069] Here, when choosing the adjustment step j, the impact on the power electronic converter needs to be considered. Generally, a smaller value is chosen, such as equal to 1. At this time, the transient process of carrier phase shift can adapt to any operating condition of the power electronic converter, achieving the effect of seamless switching.

[0070] Extended to the carrier phase shift at any θ angle, let the number of crystal oscillator clock beats corresponding to the θ angle be N2,

[0071]

[0072] If N1+N2≤n, let N ′ =N1+N2; if N1+N2>n, then let N ′ =N1+N2-n, with N ′ Replace N1 and repeat the process corresponding to formulas (e-2), (e-3), and (e-4). Due to δ t1k =δ t +δ tk By changing the angle θ, carrier phase shift of any angle from 0 to 2π can be achieved between substations.

[0073] It should be understood that in the above examples, the target count value gradually approached can take any value within the period.

[0074] Based on the above analysis, the following will combine Figure 3 To describe an exemplary embodiment of step S1042 when the phase shift angle is 0 degrees, combined with Figure 4 and Figure 5 An exemplary embodiment of step S1042 when the phase shift angle is not 0 degree is described.

[0075] Figure 3 A flow chart showing a method for processing the length of a first time interval according to a first exemplary embodiment of the present disclosure is shown. In this exemplary embodiment, the phase shift angle is 0 degrees.

[0076] Reference Figure 3 In step S201, if the specific count value is smaller than the end point of the clock beat count and larger than the middle point of the clock beat count, the length of the first time interval is shortened.

[0077] The above-mentioned clock beat counting midpoint is the midpoint between the clock beat counting start point and the clock beat counting end point.

[0078] As an example, the step of reducing the length of the first time interval may include: updating the clock beat counting starting point m to m+j, and keeping the clock beat counting end point unchanged, where j is a preset adjustment step.

[0079] In step S202, if the specific count value is less than or equal to the clock beat count midpoint, the length of the first time interval is increased.

[0080] As an example, the step of increasing the length of the first time interval may include: updating the clock beat counting start point m to mj, and keeping the clock beat counting end point unchanged.

[0081] In step S203, if the specific count value is equal to the clock beat count end point, the length of the first time interval is kept unchanged.

[0082] Figure 4 A flow chart showing a method for processing the length of a first time interval according to a second exemplary embodiment of the present disclosure is shown. In this exemplary embodiment, the phase shift angle is not 0 degrees.

[0083] Reference Figure 4 In step S301, if the sum of the number of clock beats corresponding to the above-mentioned target value and the above-mentioned specific count value is not greater than the clock beat count end point, and the above-mentioned sum is less than the clock beat count end point and greater than the clock beat count midpoint, then the length of the first time interval is shortened.

[0084] The number of clock beats corresponding to the above target value is the ratio of the above target value to a single clock beat time of the local clock.

[0085] The above-mentioned clock beat counting middle point is the midpoint between the above-mentioned clock beat counting starting point and the clock beat counting end point.

[0086] As an example, the step of reducing the length of the first time interval may include: updating the clock beat counting starting point m to m+j, and keeping the clock beat counting end point unchanged, where j is a preset adjustment step.

[0087] In step S302, if the above sum is not greater than the clock beat count midpoint, the length of the first time interval is increased.

[0088] As an example, the step of increasing the length of the first time interval may include: updating the clock beat counting start point m to mj, and keeping the clock beat counting end point unchanged.

[0089] In step S303, if the above sum is equal to the end point of the clock beat counting, the length of the first time interval is kept unchanged.

[0090] Figure 5 A flow chart showing a method for processing the length of the first time interval according to a third exemplary embodiment of the present disclosure is shown. In this exemplary embodiment, the phase shift angle is not 0 degree.

[0091] Reference Figure 5 In step S401, if the sum of the number of clock beats corresponding to the target value and the specific count value is greater than the clock beat count end point, and the difference between the above sum and the clock beat count end point is less than the clock beat count end point and greater than the clock beat count midpoint, then the length of the first time interval is shortened.

[0092] The number of clock ticks corresponding to the above target value is the ratio of the target value to a single clock tick time of the local clock.

[0093] The above-mentioned clock beat counting midpoint is the midpoint between the clock beat counting starting point and the clock beat counting end point.

[0094] As an example, the step of reducing the length of the first time interval may include: updating the clock beat counting starting point m to m+j, and keeping the clock beat counting end point unchanged, where j is a preset adjustment step.

[0095] In step S402, if the sum is greater than the end point of the clock beat count and the difference is not greater than the middle point of the clock beat count, the length of the first time interval is increased.

[0096] As an example, the step of increasing the length of the first time interval may include: updating the clock beat counting start point m to mj, and keeping the clock beat counting end point unchanged.

[0097] In step S403, if the sum is greater than the end point of the clock beat count and the difference is equal to the end point of the clock beat count, the length of the first time interval is kept unchanged.

[0098] According to the exemplary embodiments of the present disclosure, a dynamic step-by-step approximation adaptive carrier phase shifting method is proposed, a dual clock system operation mechanism and an event triggering mechanism based on the dual clock system are proposed, the construction of synchronization events, local events, carrier cycles, and time intervals (phases) is proposed, and the application of the adaptive carrier phase shifting algorithm to multiple parallel power electronic converters is proposed.

[0099] Since each converter in the new energy station executes the control method of the converter according to the exemplary embodiment of the present disclosure, the carrier phase shift between the converters in the new energy station can be realized. That is, the present disclosure actually proposes a station adaptive carrier phase shift method. Specifically, based on the high-speed synchronous control system platform, an adaptive non-inductive switching carrier phase shift method is proposed, which can realize the carrier phase shift of any angle under any state between the distributed power electronic converters in the new energy station, and can effectively suppress the high-frequency circulating current problem of the power electronic converter parallel system.

[0100] According to the control method of the converter of the exemplary embodiment of the present disclosure, the test data shows that when multiple power electronic converters are operated in parallel, carrier synchronization can be achieved, and the high-frequency circulating current suppression effect is obvious. Fig. 9 and Fig.10 , two 1.25MW converters are operated in parallel, with a carrier period of 333.33us. Through oscilloscope Fourier analysis, the high-frequency harmonic circulating current drops by more than 70% after the carriers are operated synchronously, which is far below the national standard requirements.

[0101] An exemplary embodiment of the present disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to execute the control method of the converter as described in the above exemplary embodiment. The computer-readable storage medium is any data storage device that can store data read out by a computer system. Examples of computer-readable storage media include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier wave (such as data transmission through the Internet via a wired or wireless transmission path).

[0102] According to an exemplary embodiment of the present disclosure, a controller of a converter includes: a processor (not shown) and a memory (not shown), wherein the memory stores a computer program, which, when executed by the processor, prompts the processor to execute the control method of the converter as described in the above exemplary embodiment.

[0103] A converter according to an exemplary embodiment of the present disclosure includes: a controller of the converter as described in the above exemplary embodiment.

[0104] Although some exemplary embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that modifications may be made to these embodiments without departing from the scope and spirit of the present disclosure as defined by the claims and their equivalents.

Claims

1. A control method for a converter, characterized in that: The control method comprises: generating a local event at a first time interval according to a local clock of the converter; In response to the local event being generated for a preset duration, loading a carrier; Based on the loaded carrier, generating a PWM signal for controlling the converter; Dynamically updating the length of the first time interval according to the distributed clock to achieve carrier phase shifting between the converter and other converters in the new energy station; Among them, the distributed clocks used by all converters in the new energy station are synchronized.

2. The control method according to claim 1, characterized in that: The step of dynamically updating the length of the first time interval according to the distributed clocks comprises: According to the distributed clock, a synchronization event is generated every second time interval; Dynamically update the length of the first time interval so that the time interval between the local event and the synchronization event reaches a target value; The target value is determined based on the phase shift angle and the period of the carrier.

3. The control method according to claim 2, characterized in that: The step of dynamically updating the length of the first time interval so that the time interval between the local event and the synchronization event reaches the target value includes: Based on the time when the most recent synchronization event occurs and the target value, the length of the first time interval is processed, wherein the processing is one of increasing, decreasing, and keeping unchanged.

4. The control method according to claim 2 or 3, characterized in that: The step of generating a local event at a first time interval according to a local clock of the converter comprises: According to the local clock, the clock beat count starts from the clock beat count start point. When the clock beat count end point is reached, a local event is generated and the clock beat count is restarted. The difference between the clock beat counting end point and the clock beat counting start point is: the ratio of the current length of the first time interval to the single clock beat time of the local clock.

5. The control method according to claim 4, characterized in that: The step of dynamically updating the length of the first time interval so that the time interval between the local event and the synchronization event reaches the target value includes: Determine a specific count value counted by the clock beat count at the time of generation of the most recent synchronization event; The length of the first time interval is processed based on the clock tick counting start point, the clock tick counting end point, the specific count value, and the target value.

6. The control method according to claim 5, characterized in that: The phase shift angle is 0 degrees; wherein, based on the clock beat counting starting point, the clock beat counting end point, the specific count value and the target value, the step of processing the length of the first time interval comprises: In response to the specific count value being smaller than the clock beat count end point and larger than the clock beat count middle point, shortening the length of the first time interval; In response to the specific count value being less than or equal to the clock tick count midpoint, increasing the length of the first time interval; In response to the specific count value being equal to the clock beat count end point, maintaining the length of the first time interval unchanged; The clock beat counting middle point is the midpoint between the clock beat counting start point and the clock beat counting end point.

7. The control method according to claim 5, characterized in that: The phase shift angle is not 0 degrees; wherein, based on the clock beat counting starting point, the clock beat counting end point, the specific count value and the target value, the step of processing the length of the first time interval comprises: In response to the sum of the number of clock beats corresponding to the target value and the specific count value being not greater than the clock beat count end point, and the sum being less than the clock beat count end point and greater than the clock beat count midpoint, shortening the length of the first time interval; In response to the sum being not greater than the clock tick count midpoint, increasing the length of the first time interval; In response to the sum being equal to the clock tick count end point, maintaining the length of the first time interval unchanged; Wherein, the clock beat counting middle point is the midpoint between the clock beat counting start point and the clock beat counting end point; The number of clock beats corresponding to the target value is the ratio of the target value to a single clock beat time of the local clock.

8. The control method according to claim 5, characterized in that: The phase shift angle is not 0 degrees; wherein, based on the clock beat counting starting point, the clock beat counting end point, the specific count value and the target value, the step of processing the length of the first time interval further includes: In response to the sum of the number of clock beats corresponding to the target value and the specific count value being greater than the clock beat count end point, and the difference between the sum and the clock beat count end point being less than the clock beat count end point and greater than the clock beat count midpoint, shortening the length of the first time interval; In response to the sum being greater than the clock tick count end point and the difference being no greater than the clock tick count middle point, increasing the length of the first time interval; In response to the sum being greater than the clock tick count end point and the difference being equal to the clock tick count end point, maintaining the length of the first time interval unchanged; Wherein, the clock beat counting middle point is the midpoint between the clock beat counting start point and the clock beat counting end point; The number of clock beats corresponding to the target value is the ratio of the target value to a single clock beat time of the local clock.

9. The control method according to any one of claims 6 to 8, characterized in that: The step of increasing the length of the first time interval includes: updating the clock beat counting starting point m to mj, and keeping the clock beat counting end point unchanged; The step of reducing the length of the first time interval includes: updating the clock beat counting starting point m to m+j, and keeping the clock beat counting end point unchanged; Among them, j is the preset adjustment step size.

10. The control method according to claim 2 or 3, characterized in that: The carrier is a triangular carrier; And / or, the initial value of the first time interval is the period of the carrier; And / or, the second time interval is a period of the carrier.

11. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the processor is prompted to execute the control method of the converter according to any one of claims 1 to 10.

12. A controller for a converter, characterized in that: The controller comprises: processor; A memory storing a computer program, which, when executed by a processor, causes the processor to execute the control method of the converter according to any one of claims 1 to 10.

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