Phase sequence detection method, device and equipment of three-phase alternating current and readable storage medium

Abstract

The application discloses a phase sequence detection method, device and equipment of three-phase alternating current and a readable storage medium, and belongs to the technical field of electric power. The method comprises the following steps: determining the positive and negative types of the phase sequence of the three-phase alternating current on the power grid side of a filter; in the case that the positive and negative types of the phase sequence are positive sequence, determining a first phase angle difference between a first phase angle corresponding to the three-phase alternating current on the power grid side and a second phase angle corresponding to the three-phase alternating current on the side of a three-phase converter; and finally, according to the first phase angle difference and a preset first corresponding relationship, the phase sequence of the three-phase alternating current on the power grid side can be obtained accurately. Therefore, in the case that the phase sequence of the three-phase alternating current on the power grid side is disordered, measures can be taken in time to ensure the normal operation of the three-phase converter, the reliability and safety of the three-phase converter are improved, and the maintenance cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of power technology, and in particular to a method, apparatus, device, and readable storage medium for phase sequence detection of three-phase alternating current. Background Technology

[0002] Three-phase converters (such as three-phase PWM (Pulse Width Modulation) rectifiers and three-phase grid-connected inverters) are widely used in applications requiring the injection of active and reactive power into the power grid. Due to the specific control structure of three-phase converters, it is crucial that they be connected to the three-phase AC power in the grid with the correct phase sequence. Incorrect phase sequence connection will cause the three-phase converter to malfunction, thereby affecting product reliability, increasing maintenance costs, and potentially even causing safety issues.

[0003] Therefore, how to provide a solution to the above-mentioned technical problems is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a method, apparatus, device, and readable storage medium for detecting the phase sequence of three-phase alternating current. By determining the phase sequence of the three-phase alternating current on the grid side, timely measures can be taken to ensure the normal operation of the converter, which is beneficial to the reliability and safety of the converter and reduces maintenance costs.

[0005] To solve the above-mentioned technical problems, the present invention provides a phase sequence detection method for three-phase alternating current, comprising:

[0006] Determine the positive and negative phase sequence of the three-phase AC power on the grid side of the filter;

[0007] If the positive or negative type of the phase sequence is positive, then the first phase angle difference between the first phase angle corresponding to the three-phase AC power on the grid side and the second phase angle corresponding to the three-phase AC power on the three-phase converter side of the filter is determined.

[0008] Based on the first phase angle difference and the preset first correspondence, the phase sequence of the three-phase AC power on the grid side is determined;

[0009] The filter is a filter installed between the power grid and the three-phase converter, and the first correspondence is the correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the power grid side.

[0010] Preferably, the phase sequence detection method for three-phase alternating current further includes:

[0011] If the phase sequence is negative, then the three-phase AC voltage on the grid side is reversed to obtain a three-phase AC voltage with a positive phase sequence on the grid side.

[0012] The third phase angle corresponding to the three-phase AC voltage with positive phase sequence on the grid side is determined;

[0013] The second phase angle difference between the third phase angle and the second phase angle is determined;

[0014] Based on the first correspondence, the phase sequence of the three-phase AC power on the grid side corresponding to the second phase angle difference is determined;

[0015] The phase sequence corresponding to the second phase angle difference is restored by the phase sequence reversal operation to obtain the phase sequence of the three-phase AC power on the grid side.

[0016] The phase sequence reversal operation includes swapping any two phases of the three-phase AC voltage.

[0017] Preferably, the first correspondence includes:

[0018] If the phase angle difference satisfies the first phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal R, the B phase of the grid is connected to terminal S, and the C phase of the grid is connected to terminal T.

[0019] If the phase angle difference satisfies the second phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal T, the B phase of the grid is connected to terminal R, and the C phase of the grid is connected to terminal S.

[0020] If the phase angle difference satisfies the third phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal S, the B phase of the grid is connected to terminal T, and the C phase of the grid is connected to terminal R.

[0021] Wherein, the terminal R, the terminal S, and the terminal T are all terminals that connect the filter to the three-phase AC power of the power grid.

[0022] Preferably, determining the positive or negative phase sequence of the three-phase AC power on the grid side of the filter includes:

[0023] At the beginning and end of at least one mains cycle, the three-phase AC voltage on the grid side of the filter is collected to obtain multiple sets of three-phase AC voltages.

[0024] Determine the grid voltage phase angle corresponding to each group of three-phase AC voltages;

[0025] If the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is greater than the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time, then the positive and negative type of the phase sequence of the three-phase AC power on the grid side is determined to be positive.

[0026] If the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is less than or equal to the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time, then the positive or negative type of the phase sequence of the three-phase AC power on the grid side is determined to be negative.

[0027] Preferably, determining the grid voltage phase angle corresponding to each group of three-phase AC voltages includes:

[0028] Perform a Clarke transformation on each group of three-phase AC voltages to obtain the first voltage and the second voltage located in the two-phase stationary reference frame corresponding to the three-phase AC voltages.

[0029] Based on the preset second correspondence, the grid voltage phase angle at the acquisition time of the first voltage and the three-phase AC voltage corresponding to the second voltage is determined;

[0030] The second correspondence is the correspondence between the phase angle of the two-phase stationary reference voltage and the grid voltage.

[0031] Preferably, after determining the phase sequence of the three-phase alternating current on the grid side, the phase sequence detection method for the three-phase alternating current further includes:

[0032] The phase sequence of the three-phase AC power on the grid side is sent to the controller of the three-phase converter so that the controller can determine the actual voltage, actual current and actual modulation signal of each phase in the three-phase AC power of the grid based on the received phase sequence of the three-phase AC power on the grid side.

[0033] Preferably, after determining the phase sequence of the three-phase alternating current on the grid side, the phase sequence detection method for the three-phase alternating current further includes:

[0034] Determine whether the phase sequence of the three-phase AC power on the grid side is a standard phase sequence;

[0035] If the phase sequence is not standard, the control prompt will indicate the phase sequence of the three-phase AC power on the grid side and report an error.

[0036] To solve the above-mentioned technical problems, the present invention also provides a phase sequence detection device for three-phase alternating current, comprising:

[0037] The first determining module is used to determine the positive and negative phase sequence of the three-phase AC power on the grid side of the filter;

[0038] The second determining module is used to determine the first phase angle difference between the first phase angle corresponding to the three-phase AC power on the grid side and the second phase angle corresponding to the three-phase AC power on the three-phase converter side of the filter if the positive or negative type of the phase sequence is positive.

[0039] The third determining module is used to determine the phase sequence of the three-phase AC power on the grid side based on the first phase angle difference and the preset first correspondence.

[0040] The filter is a filter installed between the power grid and the three-phase converter, and the first correspondence is the correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the power grid side.

[0041] To solve the above-mentioned technical problems, the present invention also provides a phase sequence detection device for three-phase alternating current, comprising:

[0042] Memory, used to store computer programs;

[0043] A processor is configured to execute the computer program to implement the steps of the three-phase alternating current phase sequence detection method described above.

[0044] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the three-phase alternating current phase sequence detection method described above.

[0045] This invention provides a phase sequence detection method for three-phase AC power. By determining the positive or negative type of the phase sequence of the three-phase AC power on the grid side of the filter, and when the phase sequence is positive, the method determines the first phase angle difference between the first phase angle corresponding to the three-phase AC power on the grid side and the second phase angle corresponding to the three-phase AC power on the three-phase converter side. Finally, based on the first phase angle difference and a preset first correspondence, the accurate phase sequence of the three-phase AC power on the grid side can be obtained. Therefore, in the event of a disordered phase sequence of the three-phase AC power on the grid side, timely measures can be taken to ensure the normal operation of the three-phase converter, thereby improving the reliability and safety of the three-phase converter and reducing maintenance costs.

[0046] The present invention also provides a phase sequence detection device, equipment and computer-readable storage medium for three-phase alternating current, which has the same beneficial effects as the phase sequence detection method for three-phase alternating current described above. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention, the relevant technologies and the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A schematic flowchart of a phase sequence detection method for three-phase alternating current provided in an embodiment of the present invention;

[0049] Figure 2 A schematic diagram of the structure of a phase sequence detection device for three-phase alternating current provided in an embodiment of the present invention;

[0050] Figure 3 A schematic flowchart of another three-phase alternating current phase sequence detection method provided in an embodiment of the present invention;

[0051] Figure 4 A schematic diagram of the phase angle of a power grid voltage in positive sequence connection is provided in an embodiment of the present invention;

[0052] Figure 5 A schematic diagram of the phase angle of a negative-sequence connected power grid voltage is provided for an embodiment of the present invention;

[0053] Figure 6 A schematic diagram of the structure of a phase sequence detection device for three-phase alternating current provided in an embodiment of the present invention;

[0054] Figure 7 This is a schematic diagram of another phase sequence detection device for three-phase AC power provided in an embodiment of the present invention. Detailed Implementation

[0055] The core of this invention is to provide a method, device, equipment, and readable storage medium for detecting the phase sequence of three-phase alternating current. By determining the phase sequence of the three-phase alternating current on the grid side, timely measures can be taken to ensure the normal operation of the converter, which is beneficial to the reliability and safety of the converter and reduces maintenance costs.

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] Please refer to Figure 1 , Figure 1This is a flowchart illustrating a phase sequence detection method for three-phase alternating current provided by an embodiment of the present invention. The phase sequence detection method for three-phase alternating current includes:

[0058] S101: Determine the positive and negative phase sequence of the three-phase AC power on the grid side of the filter.

[0059] Optionally, the three-phase AC voltage of the filter on the grid side is collected at different times during at least one mains power cycle, and the positive and negative phase sequence of the three-phase AC power on the grid side of the filter is determined according to the relationship between the phase angles of the grid voltages corresponding to the three-phase AC voltages of the filter on the grid side collected at different times.

[0060] Optionally, the different times can be the start and end times of a mains power cycle. Based on the relationship between the phase angles of the three-phase AC voltages on the filter's grid side collected at different times, the positive and negative types of the phase sequence of the three-phase AC power on the filter's grid side are determined. This includes determining the positive and negative types of the phase sequence of the three-phase AC power on the filter's grid side based on the relationship between the phase angles of the three-phase AC voltages on the filter's grid side collected at the start and end times of a mains power cycle.

[0061] Optionally, the different times can be any different times in multiple mains power cycles. For example, if the three-phase AC voltage is collected in two mains power cycles, the different times can be the start time of the first mains power cycle, the end time of the first mains power cycle, the start time of the second mains power cycle, the end time of the second mains power cycle, and so on.

[0062] S102: If the phase sequence is positive, then determine the first phase angle difference between the first phase angle corresponding to the three-phase AC power on the grid side and the second phase angle corresponding to the three-phase AC power on the three-phase converter side of the filter.

[0063] Specifically, considering the technical problems mentioned above, and taking into account that for a filter installed between the power grid and a three-phase converter (hereinafter referred to as the converter), the difference in the phase angle of the grid voltage between the filter's grid side and the three-phase converter side (wherein the phase angle of the grid voltage can be determined by the three-phase AC voltage) can reflect the phase sequence of the three-phase AC power on the grid side, a first correspondence relationship (i.e., the correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the grid side) is pre-set in this embodiment of the invention. When the phase sequence of the three-phase AC power on the grid side is positive, the first correspondence relationship is used to determine the phase sequence of the three-phase AC power on the grid side corresponding to the difference in the phase angle of the grid voltage between the filter's grid side and the three-phase converter side. Therefore, in this step, the positive or negative type of the phase sequence of the three-phase AC power on the filter's grid side can be determined first, and different processing can be performed according to the positive or negative type of the phase sequence.

[0064] Optionally, the three-phase AC voltage on the grid side and the three-phase converter side can be collected from various locations. For example, the three-phase AC voltage on the grid side can be collected from the terminal block on the grid side, or from any location on the grid side. This embodiment of the invention does not limit the scope of the data collection.

[0065] The positive or negative phase sequence here can include either positive or negative sequence. Positive sequence means that the grid side terminals corresponding to the three-phase AC power of the ABC power grid are arranged in the RSTR direction, including three cases: (1) AR, BS, CT (2) AT, BR, CS (3) AS, BT, CR; while negative sequence means that the grid side terminals corresponding to the three-phase AC power of the ABC power grid are arranged in the TSRT direction, where R, S and T are the three grid side terminals. Normally, the three-phase AC power of the power grid and the grid side terminals should be in the standard phase sequence, which is the first case in this paragraph.

[0066] Specifically, considering the positive sequence condition, there is a clear correspondence between the phase angle of the grid voltage corresponding to the three-phase AC voltage on the grid side and the phase angle of the grid voltage corresponding to the three-phase AC voltage on the three-phase converter side, and the phase sequence of the three-phase AC power on the grid side. Therefore, the phase sequence of the three-phase AC power on the grid side can be determined based on the first correspondence between the phase angle difference under the positive sequence condition and the phase sequence of the three-phase AC power on the grid side.

[0067] S103: Determine the phase sequence of the three-phase AC power on the grid side based on the first phase angle difference and the preset first correspondence.

[0068] Among them, the filter is a filter installed between the power grid and the three-phase converter. The first correspondence is the correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the power grid side.

[0069] Specifically, with the aforementioned data foundation, the phase sequence of the three-phase AC power on the grid side corresponding to the first phase angle difference can be determined based on the preset correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the grid side, which facilitates timely correction when the phase sequence is incorrect.

[0070] Optionally, if the phase sequence of the three-phase AC power on the power grid side of the filter is negative, an alarm can be triggered so that staff can handle the situation promptly.

[0071] This invention provides a method for phase sequence detection of three-phase alternating current. By determining the positive or negative type of the phase sequence of the three-phase alternating current on the grid side of the filter, and in the case of a positive sequence, the method determines the first phase angle difference between the first phase angle of the three-phase alternating current on the grid side and the second phase angle of the three-phase alternating current on the three-phase converter side. Based on the first phase angle difference and a preset first correspondence, the accurate phase sequence of the three-phase alternating current on the grid side can be obtained. Therefore, in the event of a disordered phase sequence of the three-phase alternating current on the grid side, timely measures can be taken to ensure the normal operation of the three-phase converter, thereby improving the reliability and safety of the three-phase converter and reducing maintenance costs. Furthermore, compared to traditional methods that require dedicated hardware circuitry for phase sequence detection, this invention can detect the phase sequence of the three-phase alternating current on the grid side without relying on dedicated hardware circuitry, thus reducing detection costs.

[0072] Based on the above embodiments:

[0073] As a preferred embodiment, the phase sequence detection method for three-phase alternating current further includes:

[0074] If the phase sequence is negative, then the phase sequence is reversed on the three-phase AC voltage on the grid side to obtain the corresponding three-phase AC voltage with positive phase sequence on the grid side.

[0075] Determine the third phase angle corresponding to the three-phase AC voltage with positive phase sequence on the grid side;

[0076] Determine the difference between the third phase angle and the second phase angle;

[0077] Based on the first correspondence, the phase sequence of the three-phase AC power on the grid side corresponding to the second phase angle difference is determined;

[0078] The phase sequence corresponding to the second phase angle difference is restored by reversing the phase sequence operation to obtain the phase sequence of the three-phase AC power on the grid side.

[0079] The phase sequence reversal operation includes swapping any two phases of the three-phase AC voltage.

[0080] Specifically, a phase sequence reversal operation is performed on the three-phase AC voltage on the grid side to obtain a three-phase AC voltage with a positive phase sequence. Then, using the three-phase AC voltage on the grid side after the phase sequence reversal operation (which converts it to positive sequence), the third phase angle of the three-phase AC current on the grid side in the positive sequence condition is determined. Next, the second phase angle difference between the third phase angle and the second phase angle can be determined. Combined with the preset first correspondence, the phase sequence of the three-phase AC current on the grid side corresponding to the second phase angle difference is determined. Since the phase sequence obtained at this time is the phase sequence after the phase sequence reversal operation, the true negative phase sequence can be obtained by performing the aforementioned phase sequence reversal operation restoration operation. The following is a specific example:

[0081] For example, if the current negative phase sequence is R(A)T(B)S(C), the positive phase sequence can be obtained by swapping any two phase voltages. For example, swapping the single-phase AC voltages of terminals R and T will give the positive phase sequence TRS. That is, the three terminals of TRS are regarded as being connected one-to-one with the single-phase AC voltages of phases A, B, and C. T corresponds to phase A, R corresponds to phase B, and S corresponds to phase C. Based on this, the difference between the third phase angle and the second phase angle is calculated. Finally, based on the first correspondence, the positive phase sequence TRS can be determined. Since the initial phase sequence reversal operation swapped the positions of the first two phases, the current negative phase sequence can be determined as RTS after the restoration operation of the above phase sequence reversal operation.

[0082] As a preferred embodiment, the first correspondence includes:

[0083] If the phase angle difference satisfies the first phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal R, the B phase of the grid is connected to terminal S, and the C phase of the grid is connected to terminal T.

[0084] If the phase angle difference satisfies the second phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal T, the B phase of the grid is connected to terminal R, and the C phase of the grid is connected to terminal S.

[0085] If the phase angle difference satisfies the third phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal S, the B phase of the grid is connected to terminal T, and the C phase of the grid is connected to terminal R.

[0086] Among them, terminal R, terminal S and terminal T are all terminals for connecting the filter to the three-phase AC power of the power grid.

[0087] Specifically, the positive sequence corresponding to the phase angle difference between the grid side and the three-phase converter side under the positive sequence can be accurately determined through the first correspondence relationship mentioned above. The first to third phase sequence conditions mentioned above can be of various types. For example, considering that for the three phase sequences with positive sequence, the theoretical corresponding phase angle difference values ​​are three fixed values ​​(i.e., ①A-R, BS, CT correspond to a phase angle difference of 0; ②A-T, BR, CS correspond to a phase angle difference of one-third π; ③A-S, BT, CR correspond to a phase angle difference of two-thirds π), but in practical applications, the phase angle difference value may have a certain error. Therefore, the first to third phase sequence conditions in the embodiments of the present invention can all be the specific numerical range of the three phase angle difference values. The specific numerical range can be the theoretical phase angle difference value ± preset deviation value corresponding to the three positive sequence phase sequences. For example, for the theoretical phase angle difference value corresponding to phase sequence ①A-R, BS, CT is 0, then the first phase sequence condition corresponding to phase sequence ①A-R, BS, CT can be (0-preset deviation value, 0+preset deviation value). If the theoretical phase angle difference between phase sequence ②A-T, BR, and CS is one-third π, then the second phase sequence condition for phase sequence ②A-T, BR, and CS can be (one-third π - preset deviation value, one-third π + preset deviation value).

[0088] Specifically, the aforementioned preset deviation value can be set independently. Of course, in addition to the aforementioned "theoretical phase angle difference corresponding to the phase sequence ± preset deviation value", the forms of the first to third phase sequence conditions can also be of various other types, which are not limited in this embodiment of the invention.

[0089] For a better explanation of the embodiments of the present invention, please refer to Figure 2 , Figure 2 This is a schematic diagram of a phase sequence detection device for three-phase AC power provided in an embodiment of the present invention. The leftmost part of the diagram represents the three-phase AC power supplied by the power grid, while the rightmost rectangle represents the three-phase converter. Between the two is a filter. RST is the terminal block connecting the filter to the three-phase AC power of the power grid, while UVW is the terminal block connecting the filter to the three-phase converter. Under normal circumstances, the connection between UVW and the three-phase converter will not be incorrect, but the terminal block on the power grid side may be connected incorrectly. The standard phase sequence on the power grid side is R connected to A, S connected to B, and T connected to C.

[0090] Specifically, Figure 2 The phase sequence detection processing module can implement the steps of the three-phase AC phase sequence detection method of the present invention when executing a computer program. The phase sequence detection processing module can be implemented based on various types of processors, such as microcontrollers. The phase sequence detection processing module can be an additional processor or a control module integrated into the converter controller. The embodiments of the present invention are not limited here.

[0091] Specifically, Figure 2 U in dc For DC voltage, C dc It is a DC capacitor, and IGBT is an Insulated Gate Bipolar Transistor.

[0092] As a preferred embodiment, determining the positive and negative phase sequence of the three-phase AC power on the grid side of the filter includes:

[0093] At the beginning and end of at least one mains cycle, the three-phase AC voltage on the grid side of the filter is collected to obtain multiple sets of three-phase AC voltages.

[0094] Determine the phase angle of the grid voltage corresponding to each group of three-phase AC voltages;

[0095] If the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is greater than the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time, then the positive and negative type of the phase sequence of the three-phase AC power on the grid side is determined to be positive.

[0096] If the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is less than or equal to the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time, then the phase sequence of the three-phase AC power on the grid side is determined to be negative.

[0097] Specifically, for a better explanation of the embodiments of the present invention, please refer to... Figure 4 and Figure 5 , Figure 4 A schematic diagram of the phase angle of the grid voltage in positive sequence connection; Figure 5 The diagram shows the phase angle of the grid voltage for a negative sequence connection. The horizontal axis represents time, and the vertical axis represents the grid voltage phase angle. It can be seen that in the case of a positive sequence connection, the grid voltage phase angle increases with time within one mains cycle, while in the case of a negative sequence connection, the grid voltage phase angle decreases with time within one mains cycle. Therefore, the positive or negative phase sequence of the three-phase AC power on the grid side of the filter can be determined based on the changes in the grid voltage phase angle corresponding to at least two sets of three-phase AC voltages collected within at least one mains cycle.

[0098] Therefore, in this embodiment of the invention, the three-phase AC voltage of the filter grid side can be collected at both the earlier and later times of at least one mains power cycle. Then, by using the relationship between the grid voltage phase angle corresponding to the three-phase AC voltage collected at the earlier time and the grid voltage phase angle corresponding to the three-phase AC voltage collected at the later time, the positive or negative type of the phase sequence of the three-phase AC power on the grid side of the filter can be determined. That is, when the grid voltage phase angle corresponding to the three-phase AC voltage collected at the later time is greater than the grid voltage phase angle corresponding to the three-phase AC voltage collected at the earlier time, the positive or negative type of the phase sequence of the three-phase AC power on the grid side is determined to be positive. When the grid voltage phase angle corresponding to the three-phase AC voltage collected at the later time is less than or equal to the grid voltage phase angle corresponding to the three-phase AC voltage collected at the earlier time, the positive or negative type of the phase sequence of the three-phase AC power on the grid side is determined to be negative.

[0099] Specifically, there are various ways to determine the relationship between the grid voltage phase angle corresponding to the three-phase AC voltage collected at a later time and the grid voltage phase angle corresponding to the three-phase AC voltage collected at an earlier time. For example, the relationship can be determined by judging the positive or negative attribute of the difference between the grid voltage phase angle corresponding to the three-phase AC voltage collected at a later time and the grid voltage phase angle corresponding to the three-phase AC voltage collected at an earlier time. This embodiment of the invention does not limit the method.

[0100] Of course, in addition to this specific method, the positive and negative types of the phase sequence of the three-phase AC power on the grid side of the filter can be determined in other specific forms, which are not limited in this embodiment of the invention.

[0101] As a preferred embodiment, determining the grid voltage phase angle corresponding to each group of three-phase AC voltages includes:

[0102] Perform a Clarke transformation on each group of three-phase AC voltages to obtain the first voltage and the second voltage located in the two-phase stationary reference frame corresponding to the three-phase AC voltages.

[0103] Based on the preset second correspondence, the grid voltage phase angle at the acquisition time of the first voltage and the three-phase AC voltage corresponding to the second voltage is determined;

[0104] The second correspondence is the correspondence between the phase angle of the two-phase stationary reference voltage and the grid voltage.

[0105] Specifically, the grid voltage phase angle at the acquisition time of each group of three-phase AC voltages can be determined efficiently and accurately using the above method.

[0106] Specifically, the Clark transformation can convert three-phase AC voltage to a two-phase stationary reference frame.

[0107] For a better explanation of the embodiments of the present invention, please refer to Figure 3 , Figure 3 This is a flowchart illustrating another phase sequence detection method for three-phase alternating current provided by an embodiment of the present invention. The calculation principle of the grid voltage phase angle is introduced first:

[0108]

[0109]

[0110] Where, θ u U is the phase angle of the grid voltage. α U is the α-axis voltage in the αβ two-phase stationary reference frame. β Let U be the β-axis voltage in the αβ two-phase stationary reference frame. The first voltage can be either the α-axis voltage or the β-axis voltage, and the second voltage can be either the α-axis voltage or the β-axis voltage (for example, the first voltage can be the α-axis voltage and the second voltage can be the β-axis voltage). ab U is the line voltage of phases ab. bc U is the line voltage of phases b and c. ca Let be the line voltage of phases ca.

[0111] Based on the above principles, refer to Figure 3 Therefore, based on the line voltage corresponding to terminal RST and terminal UVW, the phase angle of the mains voltage can also be calculated, where U... rs The line voltages at terminals r and s are given; similarly, U can be determined. st U uv And U vw The meaning, Figure 3 The first rectangle in the diagram represents the Clark transform. The Clark transform yields the α-axis and β-axis voltages, which are then processed by the aforementioned θ... u The expression can be used to calculate the grid voltage phase angle, and then the phase angle difference between the grid voltage phase angle of the filter and the three-phase converter side can be calculated.

[0112] Of course, in addition to the above method, the phase angle of the grid voltage corresponding to each group of three-phase AC voltages can also be determined by other methods, which are not limited in this embodiment of the invention.

[0113] As a preferred embodiment, after determining the phase sequence of the three-phase AC power on the grid side, the phase sequence detection method for the three-phase AC power further includes:

[0114] The phase sequence of the three-phase AC power on the grid side is sent to the controller of the three-phase converter so that the controller can determine the actual voltage, actual current and actual modulation signal of each phase in the three-phase AC power of the grid based on the received phase sequence of the three-phase AC power on the grid side.

[0115] Specifically, considering that when the controller of a three-phase converter controls the three-phase converter, if it does not know the actual phase sequence, it will assume that the phase sequence is correct and proceed with control. In this case, not only may the converter fail to work properly, but safety issues may also occur. Therefore, in order to facilitate the normal operation of the three-phase converter, the phase sequence of the three-phase AC power on the grid side can be sent to the controller of the three-phase converter so that the controller can determine the actual voltage, actual current and actual modulation signal of each phase in the three-phase AC power of the grid based on the received phase sequence of the three-phase AC power on the grid side.

[0116] Specifically, the process by which the controller determines the actual voltage, current, and modulation signal of each phase in the three-phase AC power grid based on the phase sequence of the received three-phase AC power from the grid side is to correct errors in the original three-phase control parameters (i.e., voltage, current, and modulation signal) based on the true phase sequence. For example, the original voltages of the three phases ABC are Ua, Ub, and Uc, while the true phase sequence is STR. Therefore, the original Ua is actually Uc, the original Ub is actually Ua, and the original Uc is actually Ub. The correction of the current and modulation signal of each phase is similar, and this embodiment of the invention does not limit the scope of the correction.

[0117] As a preferred embodiment, after determining the phase sequence of the three-phase AC power on the grid side, the phase sequence detection method for the three-phase AC power further includes:

[0118] Determine whether the phase sequence of the three-phase AC power on the grid side is a standard phase sequence;

[0119] If the phase sequence is not standard, the control prompt will indicate the phase sequence of the three-phase AC power on the current grid side and report an error.

[0120] Specifically, considering that non-standard phase sequence of the three-phase AC power on the grid side may cause other problems, in order to facilitate staff to understand the true incorrect phase sequence in a timely and accurate manner, in this embodiment of the invention, when the phase sequence of the three-phase AC power on the grid side is not a standard phase sequence, the control prompt device can indicate the current phase sequence of the three-phase AC power on the grid side and report the error, so that staff can understand and take appropriate action in a timely manner.

[0121] Please refer to Figure 6 , Figure 6 This is a schematic diagram of a phase sequence detection device for three-phase alternating current provided in an embodiment of the present invention. The phase sequence detection device for three-phase alternating current includes:

[0122] The first determining module 61 is used to determine the positive and negative phase sequence of the three-phase AC power on the grid side of the filter.

[0123] The second determining module 62 is used to determine the first phase angle difference between the first phase angle corresponding to the three-phase AC power on the grid side and the second phase angle corresponding to the three-phase AC power on the three-phase converter side of the filter if the positive and negative type of the phase sequence is positive.

[0124] The third determining module 63 is used to determine the phase sequence of the three-phase AC power on the grid side based on the first phase angle difference and the preset first correspondence.

[0125] Among them, the filter is a filter installed between the power grid and the three-phase converter. The first correspondence is the correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the power grid side.

[0126] As a preferred embodiment, the phase sequence detection device for three-phase alternating current further includes:

[0127] The first action module is used to perform a phase sequence reversal operation on the three-phase AC voltage on the grid side if the phase sequence is negative, so as to obtain a three-phase AC voltage with a positive phase sequence on the grid side.

[0128] The fourth determining module is used to determine the third phase angle corresponding to the three-phase AC voltage with positive phase sequence on the grid side;

[0129] The fifth determining module is used to determine the second phase angle difference between the third phase angle and the second phase angle;

[0130] The sixth determining module is used to determine the phase sequence of the three-phase AC power on the grid side corresponding to the second phase angle difference based on the first correspondence.

[0131] The restoration module is used to restore the phase sequence corresponding to the second phase angle difference through the phase sequence reversal operation, so as to obtain the phase sequence of the three-phase AC power on the grid side.

[0132] The phase sequence reversal operation includes swapping any two phases of the three-phase AC voltage.

[0133] As a preferred embodiment, the first correspondence includes:

[0134] If the phase angle difference satisfies the first phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal R, the B phase of the grid is connected to terminal S, and the C phase of the grid is connected to terminal T.

[0135] If the phase angle difference satisfies the second phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal T, the B phase of the grid is connected to terminal R, and the C phase of the grid is connected to terminal S.

[0136] If the phase angle difference satisfies the third phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal S, the B phase of the grid is connected to terminal T, and the C phase of the grid is connected to terminal R.

[0137] Among them, terminal R, terminal S and terminal T are all terminals for connecting the filter to the three-phase AC power of the power grid.

[0138] In a preferred embodiment, the first determining module 61 includes:

[0139] The acquisition submodule is used to acquire the three-phase AC voltage on the grid side of the filter at both the earlier and later times of at least one mains power cycle, to obtain multiple sets of three-phase AC voltage; and to determine the grid voltage phase angle corresponding to each set of three-phase AC voltage.

[0140] The first determination submodule is used to determine the positive or negative type of the phase sequence of the three-phase AC power on the grid side as positive if the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is greater than the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time.

[0141] The second determination submodule is used to determine the positive or negative type of the phase sequence of the three-phase AC power on the grid side as negative if the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is less than or equal to the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time.

[0142] In a preferred embodiment, the acquisition submodule is used to perform Clarke transformation on each group of three-phase AC voltages to obtain the first voltage and the second voltage located in the two-phase stationary reference frame corresponding to the three-phase AC voltages; according to the preset second correspondence, the grid voltage phase angle at the acquisition time of the three-phase AC voltages corresponding to the first voltage and the second voltage is determined; wherein, the second correspondence is the correspondence between the voltage of the two-phase stationary reference frame and the grid voltage phase angle.

[0143] In a preferred embodiment, the phase sequence detection device for three-phase alternating current further includes:

[0144] The transmitting module is used to send the phase sequence of the three-phase AC power from the grid side to the controller of the three-phase converter, so that the controller can determine the actual voltage, actual current and actual modulation signal of each phase of the three-phase AC power from the grid based on the received phase sequence of the three-phase AC power from the grid side.

[0145] In a preferred embodiment, the phase sequence detection device for three-phase alternating current further includes:

[0146] The judgment module is used to determine whether the phase sequence of the three-phase AC power on the grid side is the standard phase sequence. If it is not the standard phase sequence, the third action module is triggered.

[0147] The third action module is used to control the prompter to indicate the phase sequence of the three-phase AC power on the current power grid side and to report errors.

[0148] For a description of the phase sequence detection device for three-phase AC power provided in this embodiment of the invention, please refer to the aforementioned embodiment of the phase sequence detection method for three-phase AC power. This embodiment of the invention will not be repeated here.

[0149] Please refer to Figure 7 , Figure 7 This is a schematic diagram of another phase sequence detection device for three-phase alternating current provided in an embodiment of the present invention. The phase sequence detection device for three-phase alternating current includes:

[0150] Memory 71 is used to store computer programs;

[0151] The processor 72 is used to execute a computer program to implement the steps of the three-phase alternating current phase sequence detection method as described in the foregoing embodiments.

[0152] For a description of the phase sequence detection device for three-phase AC power provided in this embodiment of the invention, please refer to the aforementioned embodiment of the phase sequence detection method for three-phase AC power. This embodiment of the invention will not be repeated here.

[0153] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the three-phase alternating current phase sequence detection method described above.

[0154] For a description of the computer-readable storage medium provided in the embodiments of the present invention, please refer to the aforementioned embodiments of the phase sequence detection method for three-phase alternating current. The embodiments of the present invention will not be repeated here.

[0155] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section. It should also be noted that in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0156] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting the phase sequence of a three-phase alternating current, characterized in that, include: Determine the positive and negative phase sequence of the three-phase AC power on the grid side of the filter; If the positive or negative type of the phase sequence is positive, then the first phase angle difference between the first phase angle corresponding to the three-phase AC power on the grid side and the second phase angle corresponding to the three-phase AC power on the three-phase converter side of the filter is determined. Based on the first phase angle difference and the preset first correspondence, the phase sequence of the three-phase AC power on the grid side is determined; The filter is a filter installed between the power grid and the three-phase converter, and the first correspondence is the correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the power grid side.

2. The phase sequence detection method for three-phase alternating current according to claim 1, characterized in that, The phase sequence detection method for three-phase alternating current also includes: If the phase sequence is negative, then the three-phase AC voltage on the grid side is reversed to obtain a three-phase AC voltage with a positive phase sequence on the grid side. The third phase angle corresponding to the three-phase AC voltage with positive phase sequence on the grid side is determined; The second phase angle difference between the third phase angle and the second phase angle is determined; Based on the first correspondence, the phase sequence of the three-phase AC power on the grid side corresponding to the second phase angle difference is determined; The phase sequence corresponding to the second phase angle difference is restored by the phase sequence reversal operation to obtain the phase sequence of the three-phase AC power on the grid side. The phase sequence reversal operation includes swapping any two phases of the three-phase AC voltage.

3. The phase sequence detection method for three-phase alternating current according to claim 2, characterized in that, The first correspondence includes: If the phase angle difference satisfies the first phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal R, the B phase of the grid is connected to terminal S, and the C phase of the grid is connected to terminal T. If the phase angle difference satisfies the second phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal T, the B phase of the grid is connected to terminal R, and the C phase of the grid is connected to terminal S. If the phase angle difference satisfies the third phase sequence condition, then the phase sequence of the three-phase AC power on the grid side is positive, the A phase of the grid is connected to terminal S, the B phase of the grid is connected to terminal T, and the C phase of the grid is connected to terminal R. Wherein, the terminal R, the terminal S, and the terminal T are all terminals that connect the filter to the three-phase AC power of the power grid.

4. The phase sequence detection method for three-phase alternating current according to claim 1, characterized in that, The positive and negative types of the phase sequence of the three-phase AC power on the grid side of the filter are determined as follows: At the beginning and end of at least one mains cycle, the three-phase AC voltage on the grid side of the filter is collected to obtain multiple sets of three-phase AC voltages. Determine the grid voltage phase angle corresponding to each group of three-phase AC voltages; If the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is greater than the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time, then the positive and negative type of the phase sequence of the three-phase AC power on the grid side is determined to be positive. If the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at a later time is less than or equal to the phase angle of the grid voltage corresponding to the three-phase AC voltage collected at an earlier time, then the positive or negative type of the phase sequence of the three-phase AC power on the grid side is determined to be negative.

5. The phase sequence detection method for three-phase alternating current according to claim 4, characterized in that, Determining the grid voltage phase angle corresponding to each group of three-phase AC voltages includes: Perform a Clarke transformation on each group of three-phase AC voltages to obtain the first voltage and the second voltage located in the two-phase stationary reference frame corresponding to the three-phase AC voltages. Based on the preset second correspondence, the grid voltage phase angle at the acquisition time of the first voltage and the three-phase AC voltage corresponding to the second voltage is determined; The second correspondence is the correspondence between the phase angle of the two-phase stationary reference voltage and the grid voltage.

6. The phase sequence detection method for three-phase alternating current according to claim 1, characterized in that, After determining the phase sequence of the three-phase alternating current on the power grid side, the three-phase alternating current phase sequence detection method further includes: The phase sequence of the three-phase AC power on the grid side is sent to the controller of the three-phase converter so that the controller can determine the actual voltage, actual current and actual modulation signal of each phase in the three-phase AC power of the grid based on the received phase sequence of the three-phase AC power on the grid side.

7. The phase sequence detection method according to any one of claims 1 to 6, characterized in that, After determining the phase sequence of the three-phase alternating current on the power grid side, the three-phase alternating current phase sequence detection method further includes: Determine whether the phase sequence of the three-phase AC power on the grid side is a standard phase sequence; If the phase sequence is not standard, the control prompt will indicate the phase sequence of the three-phase AC power on the grid side and report an error.

8. A phase sequence detection device for three-phase alternating current, characterized in that, include: The first determining module is used to determine the positive and negative phase sequence of the three-phase AC power on the grid side of the filter; The second determining module is used to determine the first phase angle difference between the first phase angle corresponding to the three-phase AC power on the grid side and the second phase angle corresponding to the three-phase AC power on the three-phase converter side of the filter if the positive or negative type of the phase sequence is positive. The third determining module is used to determine the phase sequence of the three-phase AC power on the grid side based on the first phase angle difference and the preset first correspondence. The filter is a filter installed between the power grid and the three-phase converter, and the first correspondence is the correspondence between the phase angle difference and the phase sequence of the three-phase AC power on the power grid side.

9. A phase sequence detection device for three-phase alternating current, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the three-phase alternating current phase sequence detection method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the three-phase alternating current phase sequence detection method as described in any one of claims 1 to 7.

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