Method, device, controller and system for determining power grid phase sequence of power converter

Abstract

The invention relates to a power grid phase sequence determination method, device, controller and system for a power converter. The method comprises the following steps: when all single-phase power converters are in a grid-connected state, sending a first instruction to a target single-phase power converter; acquiring alternating current bus messages respectively corresponding to each power grid phase sequence on the alternating current bus through an electric quantity sensor arranged on the alternating current bus corresponding to each power grid phase sequence; and determining the power grid phase sequence corresponding to the target single-phase power converter based on the AC bus message corresponding to each power grid phase sequence. By adopting the method, the grid-connected opening efficiency of the single-phase power converter can be improved.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a method, apparatus, controller and system for determining the power grid phase sequence of a power converter. Background Technology

[0002] In a three-phase photovoltaic system, multiple single-phase power converters (such as microinverters) are connected to the first, second, and third phase circuits of the three-phase power grid, respectively. To improve power generation efficiency or balance the three-phase output, it is necessary to accurately determine the grid phase sequence of each single-phase power converter in the three-phase power grid system, that is, to determine which phase circuit each single-phase power converter is connected to, so as to facilitate individual control of the single-phase power converter corresponding to each phase circuit.

[0003] The grid phase sequence determination method in related technologies involves manually recording the data when a single-phase power converter is connected to a three-phase power grid, and then configuring the topology of the single-phase power converter in the gateway controller based on the recorded data.

[0004] However, using the above-mentioned grid phase sequence determination method will result in poor initial grid connection efficiency for each single-phase power converter. Summary of the Invention

[0005] Therefore, it is necessary to provide a method, apparatus, controller, and system for determining the power grid phase sequence of a power converter to improve its commissioning efficiency, in order to address the aforementioned technical problems.

[0006] In a first aspect, this application provides a method for determining the grid phase sequence of a power converter, the method being used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system; the method includes:

[0007] When all single-phase power converters are connected to the grid, a first instruction is sent to the target single-phase power converter. The first instruction is used to instruct the corresponding single-phase power converter to output power according to the first power. The target single-phase power converter is any single-phase power converter among the single-phase power converters whose grid phase sequence is not determined.

[0008] By using the power sensors installed on the AC bus corresponding to the phase sequence of each power grid, the AC bus messages corresponding to the phase sequence of each power grid are obtained.

[0009] The grid phase sequence corresponding to the target single-phase power converter is determined based on the AC bus messages corresponding to each grid phase sequence.

[0010] In one embodiment, the first instruction is used to instruct the corresponding single-phase power converter to reduce or increase the current output power by a preset power step to obtain a first power, and output according to the first power.

[0011] The target phase sequence of the target single-phase power converter is determined based on the AC bus messages corresponding to the phase sequence of each power grid, including:

[0012] Determine the phase sequence of the power grid where the AC bus message changes from the phase sequence of each power grid;

[0013] Based on the changes in the grid phase sequence caused by the AC bus message, the grid phase sequence corresponding to the target single-phase power converter is determined.

[0014] In one embodiment, the first power is greater than the sum of powers, which is the sum of the second powers corresponding to the remaining single-phase power converters.

[0015] In one embodiment, the number of single-phase power converters corresponding to each power grid phase sequence is the same, and the first power is greater than the second power.

[0016] In one embodiment, the AC bus message includes the AC bus power; determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence includes:

[0017] Determine the phase sequence of the power grid with the largest AC bus power from each power grid phase sequence;

[0018] Based on the grid phase sequence with the highest AC bus power, the grid phase sequence corresponding to the target single-phase power converter is determined.

[0019] In one embodiment, the number of single-phase power converters corresponding to each power grid phase sequence is the same; the first power is less than the second power.

[0020] In one embodiment, the AC bus message includes AC bus power;

[0021] The grid phase sequence corresponding to the target single-phase power converter is determined based on the AC bus messages corresponding to each grid phase sequence, including:

[0022] Determine the phase sequence of the power grid with the minimum AC bus power from each power grid phase sequence;

[0023] Based on the grid phase sequence with the minimum AC bus power, the grid phase sequence corresponding to the target single-phase power converter is determined.

[0024] In one embodiment, a second command is sent to a single-phase power converter whose grid phase sequence has been determined.

[0025] In one embodiment, before sending the first command to the target single-phase power converter and the second command to the remaining single-phase power converters, the method further includes:

[0026] Send a third instruction to all single-phase power converters. The third instruction is used to instruct the corresponding single-phase power converter to output power according to the third power.

[0027] Secondly, this application provides a power grid phase sequence determination device for power converters. The device is used to determine the power grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. The device includes:

[0028] The control module is used to send a first command to the target single-phase power converter when all single-phase power converters are connected to the grid. The first command is used to instruct the corresponding single-phase power converter to output according to the first power. The target single-phase power converter is any single-phase power converter among the single-phase power converters whose grid phase sequence is not determined.

[0029] The acquisition module is used to acquire AC bus messages corresponding to each phase sequence of the power grid through the power sensors installed on the AC bus corresponding to each phase sequence of the power grid.

[0030] The determination module is used to determine the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence.

[0031] Thirdly, this application provides a controller, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method as described in the first aspect.

[0032] Fourthly, this application provides a power system, including: a plurality of single-phase power converters and a controller; the controller is communicatively connected to each of the single-phase power converters;

[0033] The controller includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method as described in the first aspect.

[0034] The aforementioned method, apparatus, controller, and system for determining the power grid phase sequence of a power converter are used to determine the power grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. With all single-phase power converters in grid-connected state, a first instruction is sent to the target single-phase power converter. This first instruction instructs the corresponding single-phase power converter to output power according to a first power output. The target single-phase power converter is any one of the single-phase power converters whose power grid phase sequence has not been determined. The system acquires AC bus messages corresponding to each power grid phase sequence using electrical sensors installed on the AC bus corresponding to each power grid phase sequence. Based on the AC bus messages corresponding to each power grid phase sequence, the power grid phase sequence corresponding to the target single-phase power converter is determined. In this way, based on the parallel connection of each single-phase power converter to the AC bus of the corresponding grid phase sequence, the changes in the output power of each single-phase power converter will be reflected on the AC bus of the corresponding grid phase sequence. Therefore, under the condition that all single-phase power converters connected to the multi-phase power grid system can be connected to the grid normally, this application takes the single-phase power converter with the grid phase sequence to be identified as the target single-phase power converter, controls the output power of the target single-phase power converter through the first command, and collects the AC bus messages corresponding to each grid phase sequence on the AC bus. Based on the analysis of the AC bus messages corresponding to each grid phase sequence and the first power, the grid phase sequence corresponding to the target single-phase power converter is determined. Using the above method, the grid phase sequence corresponding to each single-phase power converter can be accurately configured without manual recording, reducing the probability of errors caused by manual configuration, and thus improving the commissioning efficiency of single-phase power converter grid connection. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a diagram illustrating the application environment of a power grid phase sequence determination method in one embodiment.

[0037] Figure 2 This is a flowchart illustrating a power grid phase sequence determination method in one embodiment;

[0038] Figure 3 This is a flowchart illustrating the steps for determining the target phase sequence of a target single-phase power converter based on the bus messages corresponding to each power grid phase sequence in one embodiment. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0040] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure.

[0042] It is understood that the terms "first," "second," etc., as used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are used only to distinguish one element from another. For example, without departing from the scope of this disclosure, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0043] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0044] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0045] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0046] The power converters described in this application are power conversion devices used to convert electrical energy from one form to another, enabling energy transmission and control under different power requirements. Power converters can be microinverters, energy storage converters, etc. For example, a microinverter can convert DC power to AC power. The DC input of the microinverter is connected to a DC source (photovoltaic module), and the AC output of the power converter can be connected to an AC power grid and AC equipment. A single-phase power converter refers to a device with a single-phase output or input on the AC side, connected to one phase of the AC power grid or AC equipment. Single-phase power converters can be single-phase microinverters, single-phase energy storage converters, etc.

[0047] In one exemplary embodiment, the provided power converter grid phase sequence determination method can be applied to, for example, Figure 1 The application environment shown. Please refer to... Figure 1 Multiple single-phase power converters 100 are respectively connected to each phase circuit of the three-phase power grid system 300 (e.g., Figure 1 As shown in L1, L2, and L3, multiple single-phase power converters can be considered as a single-phase power converter array. Controller 200 acts as the control center of this array, connecting to each phase circuit and the zero-phase circuit N of the three-phase power grid system 300. It communicates with each single-phase power converter, monitors the operating status of all single-phase power converters, and controls their output to achieve precise power control of each phase circuit of the three-phase power grid system. It also transmits device data from each single-phase power converter to the management system and cloud network management via communication methods such as FE (Fast Ethernet), WLAN (Wireless Local Area Network), 4G, or 5G. For example, controller 200 is a gateway controller; in other examples, other types of controllers can communicate with and control the on / off states of each single-phase power converter and the multi-phase power grid system. Figure 1 Each single-phase power converter shown is connected to its corresponding phase circuit during field wiring, but the controller does not obtain the wiring relationship at this time.

[0048] In this application embodiment, the power grid phase sequence is used to characterize which phase circuit in a multiphase power grid system the single-phase power converter is connected to. During the wiring process of connecting the single-phase power converter to the multiphase power grid system, the gateway controller does not pre-configure the power grid phase sequence. Related technologies use manual recording of the power grid phase sequence when the single-phase power converter is connected to the multiphase power grid, and then configuring the topology of the single-phase power converter in the gateway controller based on the recorded data. However, the above-mentioned topology identification method is inefficient. Therefore, this application embodiment provides a method for determining the power grid phase sequence of a power converter.

[0049] In one exemplary embodiment, the power converter's grid phase sequence determination method can also be applied to other multiphase grid systems, such as two-phase grid systems, and is not limited to three-phase grid systems.

[0050] In one exemplary embodiment, such as Figure 2 As shown, a method for determining the grid phase sequence of a power converter is provided, which is used for... Figure 1 The method is illustrated using controller 200 as an example. This method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. In this embodiment, the method includes steps 202 to 206, wherein:

[0051] Step 202: With all single-phase power converters in grid-connected state, send a first instruction to the target single-phase power converter. The first instruction is used to instruct the corresponding single-phase power converter to output according to the first power.

[0052] The target single-phase power converter is any single-phase power converter among those whose grid phase sequence is not determined.

[0053] After the controller is activated, it connects all single-phase power converters to their corresponding phase circuits, ensuring that each phase circuit is connected to its corresponding single-phase power converter to verify that each single-phase power converter is functioning correctly. Only after confirming that all single-phase power converters are connected to the grid does the determination of the grid phase sequence for each single-phase power converter begin. This prevents inaccurate determination of the overall grid phase sequence if a single single-phase power converter malfunctions.

[0054] In this embodiment, the corresponding grid phase sequence of each single-phase power converter is determined; each single-phase power converter is traversed, and for each single-phase power converter, the operations shown in steps 202 to 206 are performed to determine the grid phase sequence corresponding to each single-phase power converter; the single-phase power converter currently determining the grid phase sequence is called the target single-phase power converter, and the remaining single-phase power converters that have not yet determined the grid phase sequence are called the remaining single-phase power converters.

[0055] Step 204: Obtain the AC bus messages corresponding to each phase sequence of the power grid by using the power sensors installed on the AC bus corresponding to each phase sequence of the power grid.

[0056] Among them, the AC bus message corresponding to the power grid phase sequence can reflect the output status of the single-phase power converter connected to the power grid phase sequence.

[0057] Please refer to Figure 1 A power sensor 400 is installed on the AC bus corresponding to the phase sequence of each power grid to obtain the AC bus information corresponding to each phase sequence of the power grid. For example, the power sensor 400 includes a current transformer (CT). Another example is that the power sensor 400 includes a power sensor.

[0058] For example, the AC bus message is the AC bus power; the controller determines the AC bus power corresponding to each phase sequence of the power grid based on the AC bus current collected by the current transformer. In this embodiment, the AC bus power is reactive power.

[0059] For example, the AC bus message is the AC bus current; the controller obtains the AC bus current based on the current transformers or power sensors set on each phase circuit, and uses it as the AC bus message; the greater the output power of the single-phase power converter, the greater the output current of the single-phase power converter, and the greater the AC bus current.

[0060] Step 206: Determine the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence.

[0061] The output of the target single-phase power converter is reflected on the AC bus corresponding to the phase sequence of the power grid to which the target single-phase power converter is connected. First, the output power of the target single-phase power converter is controlled, and then the AC bus message that matches the output power of the target single-phase power converter is identified from the AC bus messages corresponding to each power grid phase sequence, thus determining the power grid phase sequence corresponding to the target single-phase power converter.

[0062] The grid phase sequence determination method for power converters provided in the above embodiments is used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. The method includes: sending a first instruction to a target single-phase power converter when all single-phase power converters are in grid-connected state, the first instruction being used to instruct the corresponding single-phase power converter to output according to a first power, wherein the target single-phase power converter is any one of the single-phase power converters whose grid phase sequence has not been determined; acquiring AC bus messages corresponding to each grid phase sequence through power sensors installed on the AC bus corresponding to each grid phase sequence; and determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence. Since each single-phase power converter is connected in parallel to the AC bus corresponding to the grid phase sequence, changes in the output power of each single-phase power converter will be reflected on the AC bus corresponding to the grid phase sequence. Therefore, in this embodiment, assuming that all single-phase power converters connected to the multi-phase grid system can be normally connected to the grid, the single-phase power converter with the grid phase sequence to be identified is taken as the target single-phase power converter. The output power of the target single-phase power converter is controlled by the first command, and the bus information corresponding to each grid phase sequence on the AC bus is collected. Based on the analysis of the bus information corresponding to each grid phase sequence and the first power, the grid phase sequence corresponding to the target single-phase power converter is determined. Using the above method, the grid phase sequence corresponding to each single-phase power converter can be accurately configured without manual recording, reducing the probability of errors caused by manual configuration, thereby improving the commissioning efficiency of single-phase power converter grid connection.

[0063] The grid phase sequence determination method provided in the above embodiments can accurately identify the grid phase sequence of each single-phase power converter, thereby supporting precise power control of each phase circuit and improving the power generation revenue of the power system.

[0064] In one exemplary embodiment, based on Figure 2 In the embodiment shown, the power converter's grid phase sequence determination method provides a first instruction to instruct the corresponding single-phase power converter to reduce or increase the current output power by a preset power step size to obtain a first power, and output according to the first power.

[0065] In this embodiment, a first instruction is used to instruct the target single-phase power converter to increase or decrease its output power, while the other single-phase power converters maintain their current output power. This causes a corresponding change in the current on the AC bus corresponding to the phase sequence of the power grid to which the target single-phase power converter is connected. By monitoring which power grid phase sequence corresponds to a change in the AC bus message, the target phase sequence of the target single-phase power converter is determined.

[0066] In this embodiment, please refer to Figure 3The process of determining the target phase sequence of the target single-phase power converter based on the AC bus messages corresponding to the phase sequence of each power grid includes steps 302 and 304.

[0067] Step 302: Determine the power grid phase sequence in which the AC bus message has changed from each power grid phase sequence.

[0068] Step 304: Determine the grid phase sequence corresponding to the target single-phase power converter based on the grid phase sequence of the AC bus message changes.

[0069] In one possible implementation, the first instruction is used to instruct the corresponding single-phase power converter to increase its current output power by a preset power step size to obtain a first power, and then output the first power. In the example where the AC bus message is the AC bus power, the grid phase sequence in which the AC bus power increases is determined from each grid phase sequence. This grid phase sequence in which the AC bus power increases is determined as the grid phase sequence corresponding to the target single-phase power converter. In another implementation, the grid phase sequence in which the AC bus power increases and the increase magnitude matches the preset power step size is determined from each grid phase sequence, and this grid phase sequence is determined as the grid phase sequence corresponding to the target single-phase power converter.

[0070] In one possible implementation, the first instruction is used to instruct the corresponding single-phase power converter to reduce its current output power by a preset power step size to obtain a first power, and then output the first power. In the example where the AC bus message is the AC bus power, the grid phase sequence in which the AC bus power is reduced is determined from each grid phase sequence. This grid phase sequence in which the AC bus power decreases is determined as the grid phase sequence corresponding to the target single-phase power converter. In another implementation, the grid phase sequence in which the AC bus power decreases and the magnitude of the decrease matches the preset power step size is determined from each grid phase sequence, and this grid phase sequence is determined as the grid phase sequence corresponding to the target single-phase power converter.

[0071] Based on the aforementioned implementation method where the AC bus message is the AC bus power, those skilled in the art can clearly determine the process of determining the grid phase sequence of the target single-phase power converter based on the AC bus message corresponding to each grid phase sequence in the implementation method where the AC bus message is the AC bus current. This process will not be elaborated here.

[0072] In this embodiment, the target single-phase power converter is controlled to change based on its current output power. This change is monitored by AC bus messages corresponding to each grid phase sequence, thereby determining the grid phase sequence corresponding to the target single-phase power converter. The control logic is simple.

[0073] In one exemplary embodiment, based on Figure 2The embodiment shown further includes a grid phase sequence determination method for the power converter, which involves sending a second instruction to the remaining single-phase power converters. The second instruction instructs the corresponding single-phase power converter to output a second power, where the first power is not equal to the second power. The remaining single-phase power converters are those other than the target single-phase power converter among the single-phase power converters whose grid phase sequence has not been determined.

[0074] In this embodiment, by controlling the target single-phase power converter and the other single-phase power converters to output power of different magnitudes, and combining the AC bus messages corresponding to each grid phase sequence for analysis, the grid phase sequence matching the first power is determined, and the grid phase sequence corresponding to the target single-phase power converter is determined based on the grid phase sequence.

[0075] In one possible implementation, the first power is greater than the sum of powers, which is the cumulative value of the second power corresponding to the remaining single-phase power converters.

[0076] In this configuration, the target single-phase power converter outputs power according to the first power, while the other single-phase power converters output power according to the second power. The first power is greater than the sum of the second power values ​​of the other single-phase power converters. In this case, the power transmitted on the AC bus connected to the target single-phase power converter is greater than or equal to the first power, while the power transmitted on the other two AC buses is less than the sum of the power values. This allows the phase sequence of the power grid where the target single-phase power converter is located to be identified based on the AC bus power corresponding to each phase sequence of the power grid.

[0077] For example, the number of single-phase power converters is 30, the first power is set to 1000W, and the second power is 10W. The target single-phase power converter outputs according to the first power, that is, the output power of the target single-phase power converter is 1000W. The target single-phase power converter is connected to the L1 phase circuit. In this way, the L1 phase AC bus power is greater than or equal to 1000W, and the L2 phase AC bus power and L3 phase AC bus power are both less than 290W. Thus, based on the AC bus power corresponding to each phase sequence of the power grid, the phase sequence of the power grid for the target single-phase power converter can be clearly determined to be L1 phase.

[0078] For example, the first power is greater than zero, and the second power is equal to zero; the output power of the target single-phase power converter is greater than zero, that is, the power of the AC bus connected to the target single-phase power converter is not zero, and the power of the other two AC buses is zero. In this way, the grid phase sequence of the target single-phase power converter can be clearly determined according to the AC bus power corresponding to each grid phase sequence.

[0079] In one possible implementation, the bus message includes bus power. Determining the grid phase sequence corresponding to the target single-phase power converter based on the bus messages corresponding to each grid phase sequence includes: determining the grid phase sequence with the largest bus power from each grid phase sequence, and determining the grid phase sequence with the largest bus power as the grid phase sequence corresponding to the target single-phase power converter.

[0080] In one possible implementation, there are multiple remaining single-phase power converters, and the value of the second power can be multiple. The value of the second power corresponding to each single-phase power converter can be different. As long as the cumulative value of the second power corresponding to all remaining single-phase power converters is less than the first power, the grid phase sequence corresponding to the target single-phase power converter can be determined by the AC bus power corresponding to each grid phase sequence.

[0081] In another possible implementation, there are multiple remaining single-phase power converters, and the value of the second power is 1, with the second power value being the same for each single-phase power converter.

[0082] In one possible implementation, sending the second command to the remaining single-phase power converters is performed before sending the first command to the target single-phase power converter.

[0083] For example, there are three single-phase power converters (denoted as M1, M2, and M3). First, a second instruction is sent to each single-phase power converter, causing each single-phase power converter to output according to the second power. For single-phase power converter M1, a first instruction is sent, causing single-phase power converter M1 to output according to the first power. Single-phase power converters M2 and M3 still output according to the second power, so that the AC bus power corresponding to the phase sequence of the power grid where M1 is located is greater than the AC bus power corresponding to the other two phase sequences of the power grid. The power grid phase sequence with the largest AC bus power is determined from the phase sequences of the power grid, which is the power grid phase sequence corresponding to single-phase power converter M1, assumed to be phase L1.

[0084] Then, control the single-phase power converter M2 to output power according to the first power, and the single-phase power converter M3 to output power according to the second power. Send a second command to the single-phase power converter M1, which has already identified the grid phase sequence, so that the single-phase power converter M1 also outputs power according to the second power. Determine the grid phase sequence with the largest AC bus power from each grid phase sequence. This is the grid phase sequence corresponding to the single-phase power converter M2, which is assumed to be phase L2.

[0085] Then, control the single-phase power converter M3 to output the first power, while the single-phase power converter M1 continues to output the second power. Send a second command to the single-phase power converter M2, which has already identified the grid phase sequence, so that the single-phase power converter M2 also outputs the second power. Determine the grid phase sequence with the largest AC bus power from each grid phase sequence. This is the grid phase sequence corresponding to the single-phase power converter M3, let's assume it's phase L3.

[0086] In some embodiments, a second instruction is not sent to the single-phase power converter that has already identified the grid phase sequence, so that it continues to output power according to the first power; in this case, a grid phase sequence with the largest AC bus power may occur; in one possible implementation, the process of determining the grid phase sequence with the largest AC bus power from each grid phase sequence may include: subtracting the output power of the single-phase power converter that has already identified the grid phase sequence from the corresponding AC bus power to obtain the updated AC bus power, and determining the grid phase sequence with the largest updated AC bus power from each grid phase sequence.

[0087] In one possible implementation, the AC bus message includes the AC bus current. Determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence includes: determining the grid phase sequence with the largest AC bus current from each grid phase sequence, and determining the grid phase sequence with the largest AC bus current as the grid phase sequence corresponding to the target single-phase power converter.

[0088] In one exemplary embodiment, based on Figure 2 In the embodiment shown, the grid phase sequence determination method for the provided power converter has the same number of single-phase power converters corresponding to each grid phase sequence, and the first power is greater than the second power.

[0089] In this embodiment, the second power corresponding to each of the remaining single-phase power converters is the same. Based on the first power, the second power, and the AC bus messages, the grid phase sequence corresponding to the target single-phase power converter is determined. In embodiments where the AC bus messages include AC bus power, the process of determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence includes: determining the grid phase sequence with the largest AC bus power from among the grid phase sequences; and determining the grid phase sequence corresponding to the target single-phase power converter based on the grid phase sequence with the largest AC bus power.

[0090] Among them, a single-phase power converter that has identified the phase sequence of the power grid can output power according to the second power output or according to other power values.

[0091] In one possible implementation, the single-phase power converter that has identified the grid phase sequence is also controlled to output power according to the second power; correspondingly, the grid phase sequence with the largest AC bus power is determined from each grid phase sequence, and the grid phase sequence with the largest AC bus power is determined as the grid phase sequence corresponding to the target single-phase power converter.

[0092] In one possible implementation, the single-phase power converters whose grid phase sequence has been identified output power values ​​of other magnitudes, since the grid phase sequence corresponding to these single-phase power converters is already known. Based on the AC bus messages, the output power of the single-phase power converters whose grid phase sequence has been identified at each grid phase sequence, the number of single-phase power converters whose grid phase sequence has not been identified, the first power and the second power, the grid phase sequence corresponding to the target single-phase power converter is determined.

[0093] In one exemplary embodiment, based on Figure 2 In the embodiment shown, the grid phase sequence determination method for the provided power converter ensures that the number of single-phase power converters corresponding to each grid phase sequence is the same. The first power is less than the second power.

[0094] In this embodiment, when there are multiple other single-phase power converters, the second power corresponding to each of the other single-phase power converters is the same, and the output power of the single-phase power converter that has identified the grid phase sequence is also the second power. Thus, in this embodiment, except for the target single-phase power converter which outputs according to the first power, the remaining single-phase power converters all output according to the second power.

[0095] Determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence includes: determining the grid phase sequence with the smallest value represented by the AC bus message from each grid phase sequence, and determining this grid phase sequence as the grid phase sequence corresponding to the target single-phase power converter.

[0096] In one possible implementation, the AC bus message includes the AC bus power. Determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence includes: determining the grid phase sequence with the minimum AC bus power from each grid phase sequence, and determining the grid phase sequence with the minimum AC bus power as the grid phase sequence corresponding to the target single-phase power converter.

[0097] For example, the number of single-phase power converters is 30, and the number of single-phase power converters corresponding to each grid phase sequence is 10. The first power is set to 10W, and the second power is 100W. The target single-phase power converter outputs according to the first power, that is, the output power of the target single-phase power converter is 10W. The target single-phase power converter is connected to the L1 phase circuit. The output power of the single-phase power converter whose grid phase sequence has been identified is also the second power. In this way, the L1 phase AC bus power is 910W, and the L2 phase AC bus power and L3 phase AC bus power are both equal to 1000W. Thus, according to the AC bus power corresponding to each grid phase sequence, it can be clearly determined that the grid phase sequence of the target single-phase power converter is L1 phase.

[0098] In one possible implementation, the AC bus message includes the AC bus current. Determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence includes: determining the grid phase sequence with the smallest AC bus current from each grid phase sequence, and determining the grid phase sequence with the smallest AC bus current as the grid phase sequence corresponding to the target single-phase power converter.

[0099] In some embodiments, the grid phase sequence determination method for the provided power converter further includes: sending a second instruction to the single-phase power converter whose grid phase sequence has been determined. Thus, in the process of determining the grid phase sequence corresponding to the target single-phase power converter, all single-phase power converters other than the target single-phase power converter output power according to the second instruction, simplifying the process of determining the grid phase sequence corresponding to the target single-phase power converter based on bus messages.

[0100] In one exemplary embodiment, based on Figure 2 In the embodiment shown, the power converter grid phase sequence determination method further includes sending a third instruction to all single-phase power converters before sending the first instruction to the target single-phase power converter. The third instruction instructs the corresponding single-phase power converter to output power according to a third power output.

[0101] Thus, before traversing each single-phase power converter to determine the corresponding grid phase sequence, all single-phase power converters are controlled to output at the third power. This ensures normal communication between the single-phase power converters and the controller. Furthermore, in some scenarios, a single-phase power converter may start generating electricity at its maximum power point after detecting power generation from a connected generator. Therefore, the output power of each single-phase power converter may differ. Controlling all single-phase power converters to output at the third power ensures that all single-phase power converters have the same control starting point, improving the reliability of subsequent grid phase sequence determination. In this embodiment, the magnitude of the third power is not specifically limited.

[0102] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0103] It is understood that the term "based on" as used in this application is used to describe one or more factors that influence the determination, but does not exclude other factors that may influence the determination. For example, the phrase "determine A based on B" means that the determination of A can be based entirely or at least partially on factor B. That is, B is a factor that influences the determination of A, but does not exclude the fact that the determination of A is also based on C.

[0104] Based on the same inventive concept, this application also provides a power grid phase sequence determination device for implementing the power grid phase sequence determination method for the power converter described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations in the embodiments of the power grid phase sequence determination device for one or more power converters provided below can be found in the limitations of the power grid phase sequence determination method for power converters described above, and will not be repeated here.

[0105] In an exemplary embodiment, a power converter grid phase sequence determination device is provided for identifying the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. The grid phase sequence determination device includes: a control module, an acquisition module, and a determination module, wherein:

[0106] The control module is used to send a first command to the target single-phase power converter when all single-phase power converters are connected to the grid. The first command is used to instruct the corresponding single-phase power converter to output according to the first power. The target single-phase power converter is any single-phase power converter among the single-phase power converters whose grid phase sequence is not determined.

[0107] The acquisition module is used to acquire AC bus messages corresponding to each phase sequence of the power grid through the power sensors installed on the AC bus corresponding to each phase sequence of the power grid.

[0108] The determination module is used to determine the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each grid phase sequence.

[0109] In an exemplary embodiment, the first instruction is used to instruct the corresponding single-phase power converter to reduce or increase the current output power by a preset power step size to obtain a first power, and output according to the first power; the determining module is used to determine the grid phase sequence in which the AC bus message changes from each grid phase sequence, and determine the grid phase sequence corresponding to the target single-phase power converter based on the grid phase sequence in which the AC bus message changes.

[0110] In an exemplary embodiment, the control module is further configured to send a second instruction to the remaining single-phase power converters, the second instruction being configured to instruct the corresponding single-phase power converters to output according to a second power, the second power being not equal to the first power; the remaining single-phase power converters are single-phase power converters other than the target single-phase power converter among the single-phase power converters whose grid phase sequence is not determined.

[0111] In one exemplary embodiment, the first power is greater than the sum of powers, which is the sum of the second powers corresponding to the remaining single-phase power converters.

[0112] In one exemplary embodiment, the number of single-phase power converters corresponding to each power grid phase sequence is the same, and the first power is greater than the second power.

[0113] In an exemplary embodiment, the AC bus message includes AC bus power, and the determination module is used to determine the grid phase sequence with the largest AC bus power from each grid phase sequence; based on the grid phase sequence with the largest AC bus power, the grid phase sequence corresponding to the target single-phase power converter is determined.

[0114] In one exemplary embodiment, the number of single-phase power converters corresponding to each power grid phase sequence is the same; the first power is less than the second power.

[0115] In an exemplary embodiment, the AC bus message includes AC bus power, and the determination module is used to determine the grid phase sequence with the minimum AC bus power from each grid phase sequence; based on the grid phase sequence with the minimum AC bus power, the grid phase sequence corresponding to the target single-phase power converter is determined.

[0116] In one exemplary embodiment, the control module is used to send a second command to a single-phase power converter whose grid phase sequence has been determined.

[0117] In an exemplary embodiment, the control module is used to send a third instruction to all single-phase power converters, the third instruction being used to instruct the corresponding single-phase power converter to output power according to a third power.

[0118] The various modules in the power grid phase sequence determination device of the aforementioned power converter can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in the network device, or stored in software in the memory of the network device, so that the processor can call and execute the corresponding operations of each module.

[0119] In one exemplary embodiment, a controller is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the method embodiments described above.

[0120] In one exemplary embodiment, a power system is provided, please refer to Figure 1 The power system includes: multiple single-phase power converters and a controller. The controller is communicatively connected to each single-phase power converter; the controller includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps in the above method embodiments.

[0121] In one possible implementation, the controller communicates with each single-phase power converter via power line communication (PLC).

[0122] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the above method embodiments.

[0123] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0124] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0125] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0126] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining the power grid phase sequence of a power converter, characterized in that, The method is used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system. The method includes: When all single-phase power converters are connected to the grid, a first instruction is sent to the target single-phase power converter. The first instruction is used to instruct the corresponding single-phase power converter to output according to the first power. The target single-phase power converter is any one of the single-phase power converters whose grid phase sequence is not determined. By using the power sensors installed on the AC bus corresponding to the phase sequence of each power grid, the AC bus messages corresponding to the phase sequence of each power grid are obtained. The grid phase sequence corresponding to the target single-phase power converter is determined based on the AC bus messages corresponding to each of the grid phase sequences.

2. The method according to claim 1, characterized in that, The first instruction is used to instruct the corresponding single-phase power converter to reduce or increase the current output power by a preset power step size to obtain the first power, and output according to the first power; Determining the target phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each of the power grid phase sequences includes: Determine the power grid phase sequence in which the AC bus message changes from each of the aforementioned power grid phase sequences; Based on the change in the grid phase sequence of the AC bus message, the grid phase sequence corresponding to the target single-phase power converter is determined.

3. The method according to claim 1, characterized in that, The method further includes: A second instruction is sent to the remaining single-phase power converters. The second instruction is used to instruct the corresponding single-phase power converter to output according to the second power, which is not equal to the first power. The remaining single-phase power converters are single-phase power converters other than the target single-phase power converter among the single-phase power converters whose grid phase sequence is not determined.

4. The method according to claim 3, characterized in that, The first power is greater than the sum of powers, where the sum of powers is the accumulated value of the second power corresponding to the remaining single-phase power converters.

5. The method according to claim 3, characterized in that, The number of single-phase power converters corresponding to each power grid phase sequence is the same, and the first power is greater than the second power.

6. The method according to claim 4 or 5, characterized in that, The AC bus message includes AC bus power; determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each of the grid phase sequences includes: Determine the power grid phase sequence with the largest AC bus power from each of the aforementioned power grid phase sequences; The grid phase sequence corresponding to the target single-phase power converter is determined based on the grid phase sequence with the maximum AC bus power.

7. The method according to claim 3, characterized in that, The number of single-phase power converters corresponding to each power grid phase sequence is the same; the first power is less than the second power.

8. The method according to claim 7, characterized in that, The AC bus message includes AC bus power; Determining the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each of the grid phase sequences includes: Determine the power grid phase sequence with the minimum AC bus power from all the aforementioned power grid phase sequences; The grid phase sequence corresponding to the target single-phase power converter is determined based on the grid phase sequence with the minimum AC bus power.

9. The method according to any one of claims 3-5, 7 and 8, characterized in that, The method further includes: Send the second command to the single-phase power converter whose grid phase sequence has been determined.

10. The method according to claim 1, characterized in that, Before sending the first command to the target single-phase power converter, the method further includes: A third instruction is sent to all the single-phase power converters, the third instruction being used to instruct the corresponding single-phase power converter to output a third power.

11. A power grid phase sequence determination device for a power converter, characterized in that, The device is used to determine the grid phase sequence corresponding to each single-phase power converter connected to a multiphase power grid system, and the device includes: The control module is used to send a first instruction to the target single-phase power converter when all single-phase power converters are connected to the grid. The first instruction is used to instruct the corresponding single-phase power converter to output a first power. The target single-phase power converter is any one of the single-phase power converters whose grid phase sequence is not determined. The acquisition module is used to acquire AC bus messages corresponding to each phase sequence of the power grid through the power sensors installed on the AC bus corresponding to each phase sequence of the power grid. The determination module is used to determine the grid phase sequence corresponding to the target single-phase power converter based on the AC bus messages corresponding to each of the grid phase sequences.

12. A controller, characterized in that, It includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1 to 10.

13. An electric power system, characterized in that, The power system includes: multiple single-phase power converters and a controller; the controller is communicatively connected to each of the single-phase power converters. The controller includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method according to any one of claims 1 to 10.

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