Anti-fluctuation power electronic equipment low voltage ride through control method and system

Abstract

The invention provides an anti-fluctuation power electronic equipment low-voltage ride-through control method and system, and the method comprises the steps: outputting a positive-sequence dq-axis current instruction value and a negative-sequence dq-axis current instruction value of power electronic equipment through an outer-ring controller of the power electronic equipment; performing amplitude limiting on the positive-sequence dq-axis current instruction value through an inner ring controller of the power electronic equipment to obtain a positive-sequence voltage three-phase instruction value; obtaining a negative sequence voltage three-phase instruction value through an inner ring controller according to the negative sequence dq axis current reference value; according to the positive sequence voltage three-phase instruction value and the negative sequence voltage three-phase instruction value, low-voltage ride-through control is carried out on the power electronic equipment; in the low voltage ride through process of the power electronic equipment, the current control of the power electronic equipment is realized by limiting the amplitude of the positive sequence dq axis current instruction value and correcting the positive sequence current instruction value of the power electronic equipment, so that the power fluctuation is reduced before the equipment generates the power fluctuation, and the voltage fluctuation is controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a low voltage ride-through control method and system for power electronic equipment to prevent fluctuations. Background Art

[0002] At present, the significance of preventing voltage fluctuations in power electronic equipment is far-reaching. It is not only related to the stable operation of the power system, but also a key measure for the protection of various types of equipment. Voltage stability plays a vital role in the life of equipment, the continuity of production lines, and the improvement of economic benefits. By preventing voltage fluctuations, the equipment failure rate can be greatly reduced, the continuity of the production process can be ensured, and it helps to improve the economic benefits of the enterprise. Therefore, it is of great strategic significance for enterprises to pay attention to and take effective measures to prevent voltage fluctuations in power electronic equipment.

[0003] Prior to the technology of the present invention, in the prior art, during the low voltage ride-through process, it is often necessary to consider how to set the control mode of the corresponding outer loop control. Commonly used control modes include DC voltage control, active power control, reactive power control and AC voltage control. However, under different control modes, possible fluctuations are also different. However, in each control strategy, if the positive sequence current is obtained through the positive sequence component of the voltage, fluctuation deviations may occur due to low transmission power. Summary of the invention

[0004] In order to solve the problem that the positive sequence current is obtained through the positive sequence component of the voltage during the low voltage ride through process of the power electronic equipment for anti-fluctuation in the prior art, which is prone to fluctuation deviation, the present invention proposes a low voltage ride through control method for power electronic equipment for anti-fluctuation, comprising:

[0005] Outputting a positive-sequence dq-axis current command value and a negative-sequence dq-axis current command value of the power electronic equipment through an outer loop controller of the power electronic equipment;

[0006] The positive-sequence dq-axis current command value is limited by the inner loop controller of the power electronic equipment to obtain a positive-sequence voltage three-phase command value;

[0007] According to the negative-sequence dq-axis current command value, a negative-sequence voltage three-phase command value is obtained through the inner loop controller;

[0008] According to the positive-sequence voltage three-phase command value and the negative-sequence voltage three-phase command value, low voltage ride-through control is performed on the power electronic equipment.

[0009] Optionally, the outputting of the positive-sequence dq-axis current command value and the negative-sequence dq-axis current command value of the power electronic equipment through the outer loop controller of the power electronic equipment includes:

[0010] When the outer loop controller of the power electronic equipment is a positive-sequence outer loop controller, and the operation mode of the outer loop controller is grid-following control, according to the acquired positive-sequence power command value of the power electronic equipment, an command calculation strategy is adopted to calculate the positive-sequence dq-axis current command value of the power electronic equipment;

[0011] When the outer loop controller is a positive-sequence outer loop controller and the operation mode of the outer loop controller is grid-type control, the positive-sequence dq-axis current command value of the power electronic equipment is output through the outer loop controller;

[0012] When the outer loop controller is a negative-sequence outer loop controller, the negative-sequence dq-axis current command value of the power electronic equipment is output through the outer loop controller.

[0013] Optionally, the positive-sequence power command value includes: a positive-sequence active power command value and a positive-sequence reactive power command value;

[0014] The positive-sequence dq-axis current command value comprises: a positive-sequence d-axis current command value and a positive-sequence q-axis current command value;

[0015] The negative-sequence dq-axis current command value includes: a negative-sequence d-axis current command value and a negative-sequence q-axis current command value.

[0016] Optionally, the calculation formula corresponding to the instruction calculation strategy is as follows:

[0017]

[0018] Among them, i d Indicates the positive sequence d-axis current command value; i q Indicates the positive sequence q-axis current command value; u d Indicates the positive sequence voltage d-axis acquisition value; p ′ Indicates the positive sequence active power command value; u q Indicates the q-axis acquisition value of the positive sequence voltage; q ′ represents the positive sequence reactive power command value; A represents the updated intermediate limit variable.

[0019] Optionally, the updating process of the intermediate restriction variable A is as follows:

[0020] Calculating an initial intermediate limiting variable according to the acquired positive-sequence voltage d-axis acquisition value and the positive-sequence voltage q-axis acquisition value of the power electronic equipment;

[0021] When the initial intermediate limiting variable is less than or equal to a preset limiting margin, taking the limiting margin as an updated intermediate limiting variable;

[0022] When the initial intermediate limiting variable is greater than the limiting margin, the initial intermediate limiting variable is used as the updated intermediate limiting variable.

[0023] Optionally, the calculation formula corresponding to the initial intermediate restriction variable is as follows:

[0024]

[0025] Where A represents the initial intermediate restriction variable; u d Indicates the d-axis acquisition value of the positive sequence voltage; u q Indicates the q-axis sampled value of the positive sequence voltage.

[0026] Optionally, the inner loop controller of the power electronic equipment limits the positive-sequence dq-axis current command value to obtain a positive-sequence voltage three-phase command value, including:

[0027] Limiting the positive-sequence d-axis current command value by an inner-loop controller of the power electronic equipment to obtain a positive-sequence d-axis current command value after limiting;

[0028] By means of the inner loop controller, the positive-sequence q-axis current command value is limited to obtain the positive-sequence q-axis current command value after limiting;

[0029] According to the positive-sequence d-axis current command value after the limiting, the positive-sequence voltage d-axis command value is output through the proportional-integral controller;

[0030] According to the positive-sequence q-axis current command value after the limiting, the positive-sequence voltage q-axis command value is output through the proportional-integral controller;

[0031] According to the positive-sequence voltage d-axis command value and the positive-sequence voltage q-axis command value, the positive-sequence voltage three-phase command value is obtained through the coordinate system transformation in the inner loop controller.

[0032] Based on the same inventive concept, the present invention also provides a low voltage ride-through control system for power electronic equipment to prevent fluctuations, comprising:

[0033] An outer loop output module, used for outputting a positive sequence dq axis current command value and a negative sequence dq axis current command value of the power electronic equipment through an outer loop controller of the power electronic equipment;

[0034] A positive sequence inner loop output module, used to limit the positive sequence dq axis current command value through the inner loop controller of the power electronic equipment to obtain a positive sequence voltage three-phase command value;

[0035] A negative-sequence inner loop output module, used to obtain a negative-sequence voltage three-phase command value through the inner loop controller according to the negative-sequence dq-axis current command value;

[0036] A low voltage ride through control module is used to perform low voltage ride through control on the power electronic equipment according to the positive sequence voltage three-phase command value and the negative sequence voltage three-phase command value.

[0037] Optionally, the outer loop output module includes:

[0038] A grid-following control unit, configured to calculate the positive-sequence dq-axis current command value of the power electronic equipment by adopting a command calculation strategy according to the acquired positive-sequence power command value of the power electronic equipment when the outer-loop controller of the power electronic equipment is a positive-sequence outer-loop controller and the operation mode of the outer-loop controller is grid-following control;

[0039] A network control unit, configured to output the positive-sequence dq-axis current command value of the power electronic equipment through the outer loop controller when the outer loop controller is a positive-sequence outer loop controller and the operation mode of the outer loop controller is network-type control;

[0040] A negative-sequence control unit is used to output the negative-sequence dq-axis current command value of the power electronic equipment through the outer loop controller when the outer loop controller is a negative-sequence outer loop controller.

[0041] Optionally, the positive-sequence power command value in the grid-following control unit includes: a positive-sequence active power command value and a positive-sequence reactive power command value;

[0042] The positive-sequence dq-axis current command value comprises: a positive-sequence d-axis current command value and a positive-sequence q-axis current command value;

[0043] The negative-sequence dq-axis current command value includes: a negative-sequence d-axis current command value and a negative-sequence q-axis current command value.

[0044] Optionally, the calculation formula corresponding to the instruction calculation strategy in the network control unit is as follows:

[0045]

[0046] Among them, i d Indicates the positive sequence d-axis current command value; i q Indicates the positive sequence q-axis current command value; u d Indicates the positive sequence voltage d-axis acquisition value; o ′ Indicates the positive sequence active power command value; u q Indicates the q-axis acquisition value of the positive sequence voltage; q ′ represents the positive sequence reactive power command value; A represents the updated intermediate limit variable.

[0047] Optionally, the network following control unit may include:

[0048] An initial variable calculation subunit, used to calculate an initial intermediate limiting variable according to the acquired positive sequence voltage d-axis acquisition value and the positive sequence voltage q-axis acquisition value of the power electronic equipment;

[0049] A first updating subunit, configured to use the limit margin as an updated intermediate limit variable when the initial intermediate limit variable is less than or equal to a preset limit margin;

[0050] The second updating subunit is configured to use the initial intermediate limiting variable as an updated intermediate limiting variable when the initial intermediate limiting variable is greater than the limiting margin.

[0051] Optionally, the calculation formula corresponding to the initial intermediate limiting variable in the network control unit is as follows:

[0052]

[0053] Where A represents the initial intermediate restriction variable; u d Indicates the d-axis acquisition value of the positive sequence voltage; u q Indicates the q-axis sampled value of the positive sequence voltage.

[0054] Optionally, the positive sequence inner loop output module includes:

[0055] The d-axis limiting unit is used to limit the positive-sequence d-axis current command value through the inner loop controller of the power electronic equipment to obtain the positive-sequence d-axis current command value after limiting.

[0056] a q-axis limiting unit, used for limiting the positive-sequence q-axis current command value through the inner loop controller to obtain the positive-sequence q-axis current command value after limiting;

[0057] A d-axis command value output unit, used to output a positive-sequence voltage d-axis command value through the proportional-integral controller according to the positive-sequence d-axis current command value after the limiting;

[0058] A q-axis command value output unit, used to output a positive-sequence voltage q-axis command value through the proportional-integral controller according to the positive-sequence q-axis current command value after the limiting;

[0059] The coordinate system conversion unit is used to obtain the positive sequence voltage three-phase command value through the coordinate system transformation in the inner loop controller according to the positive sequence voltage d-axis command value and the positive sequence voltage q-axis command value.

[0060] In another aspect, the present invention further provides an electronic device, comprising: at least one processor and a memory; the memory and the processor are connected via a bus;

[0061] The memory is used to store one or more programs;

[0062] When the one or more programs are executed by the at least one processor, the aforementioned anti-fluctuation low voltage ride-through control method for power electronic equipment is implemented.

[0063] On the other hand, the present invention further provides a computer-readable storage medium having an execution program stored thereon, and when the execution program is executed, the aforementioned anti-fluctuation low voltage ride-through control method for power electronic equipment is implemented.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The present invention provides a low voltage ride-through control method and system for power electronic equipment with anti-fluctuation, comprising: outputting a positive-sequence dq-axis current command value and a negative-sequence dq-axis current command value of the power electronic equipment through an outer loop controller of the power electronic equipment; limiting the positive-sequence dq-axis current command value through an inner loop controller of the power electronic equipment to obtain a positive-sequence voltage three-phase command value; obtaining a negative-sequence voltage three-phase command value through the inner loop controller according to the negative-sequence dq-axis current command value; performing low voltage ride-through control on the power electronic equipment according to the positive-sequence voltage three-phase command value and the negative-sequence voltage three-phase command value; in the process of performing low voltage ride-through on the power electronic equipment, the present application limits the positive-sequence dq-axis current command value and corrects the positive-sequence current command value of the power electronic equipment to achieve current control of the power electronic equipment, so that the equipment can reduce power fluctuations before generating power fluctuations, thereby controlling voltage fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a flow chart of a low voltage ride through control method for power electronic equipment with anti-fluctuation provided by the present invention;

[0067] Figure 2 It is a schematic diagram of the control framework of an outer loop controller in a low voltage ride-through control method for power electronic equipment to prevent fluctuations provided by the present invention;

[0068] Figure 3 It is a schematic diagram of the structure of a low voltage ride-through control system for power electronic equipment to prevent fluctuations provided by the present invention;

[0069] Figure 4 The present invention provides a schematic structural diagram of an electronic device. DETAILED DESCRIPTION

[0070] The present invention provides a method and system for controlling low voltage ride-through of power electronic equipment to prevent fluctuations. The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0071] Embodiment 1:

[0072] A low voltage ride-through control method for power electronic equipment to prevent fluctuations, the flow chart is as follows Figure 1 As shown, including:

[0073] Step 1: outputting a positive-sequence dq-axis current command value and a negative-sequence dq-axis current command value of the power electronic equipment through an outer loop controller of the power electronic equipment;

[0074] Step 2: The positive-sequence dq-axis current command value is limited by the inner loop controller of the power electronic equipment to obtain the positive-sequence voltage three-phase command value;

[0075] Step 3: According to the negative-sequence dq-axis current reference value, the negative-sequence voltage three-phase command value is obtained through the inner loop controller;

[0076] Step 4: Perform low voltage ride-through control on the power electronic equipment according to the positive sequence voltage three-phase command value and the negative sequence voltage three-phase command value.

[0077] In one implementation, Figure 2 As shown, the process of outputting the positive-sequence dq-axis current command value and the negative-sequence dq-axis current command value of the power electronic equipment through the outer loop controller of the power electronic equipment in the above step 1 may include:

[0078] When the outer loop controller of the power electronic equipment is a positive-sequence outer loop controller, and the operation mode of the outer loop controller is grid-following control, the positive-sequence dq-axis current command value of the power electronic equipment is calculated by adopting the command calculation strategy according to the acquired positive-sequence power command value of the power electronic equipment;

[0079] When the outer loop controller is a positive-sequence outer loop controller, and the operation mode of the outer loop controller is grid-type control, the positive-sequence dq-axis current command value of the power electronic equipment is output through the outer loop controller;

[0080] When the outer loop controller is a negative-sequence outer loop controller, the negative-sequence dq-axis current command value of the power electronic equipment is output through the outer loop controller;

[0081] In this implementation, when the operation mode of the outer loop controller is grid-forming control, the positive-sequence power command value and reactive power command value are no longer output, and the positive-sequence d-axis current command value and the positive-sequence q-axis current command value are directly output. This direct control method is conducive to simplifying the control logic of power electronic equipment, improving the response speed and stability of the power system, and can reduce intermediate links, making the control of power electronic equipment more direct and efficient; when the operation mode of the outer loop controller is grid-following control, the positive-sequence reactive power command value and the positive-sequence active power command value are calculated by a proportional integral controller (also called a PI controller), and when calculating the positive-sequence active power reference value, the DC voltage (mode 1) or active power (mode 2) control mode is preferably used;

[0082] For example, the positive-sequence power command value mentioned above may include: a positive-sequence active power command value and a positive-sequence reactive power command value; the positive-sequence active power command value and the positive-sequence reactive power command value obtained by the present invention are generated based on two control modes, namely the above-mentioned mode 1 and mode 2. In the DC voltage control mode, the main goal of the system is to maintain the stability of the DC side voltage, which helps to ensure that the inverter or power electronic equipment can maintain a stable operating state under various operating conditions; in the active power control mode, the system outputs a predetermined active power according to the dispatch instruction or market transaction plan, which helps to improve the dispatchability of the system and ensure that the system can meet external needs. By combining these two control modes, the operating state of the system can be flexibly adjusted according to different operating conditions and needs, which can not only maintain the stability of the DC side voltage, but also meet external dispatch requirements, thereby improving the flexibility and economy of the entire system.

[0083] For example, the positive-sequence dq-axis current command value mentioned above may include: a positive-sequence d-axis current command value and a positive-sequence q-axis current command value;

[0084] For example, the negative-sequence dq-axis current command value mentioned above may include: a negative-sequence d-axis current command value and a negative-sequence q-axis current command value.

[0085] For example, the calculation formula corresponding to the above instruction calculation strategy is as follows:

[0086]

[0087] Among them, i d Indicates the positive sequence d-axis current command value; i q Indicates the positive sequence q-axis current command value; u d Indicates the positive sequence voltage d-axis acquisition value; p ′ Indicates the positive sequence active power command value; u q Indicates the q-axis acquisition value of the positive sequence voltage; q ′Represents the positive-sequence reactive power command value; A represents the updated intermediate limiting variable; the present invention can obtain the positive-sequence dq-axis current command value by adopting the command calculation strategy, but in order to prevent the abnormality caused by the non-zero positive-sequence dq-axis current command value and to adapt to the corresponding outer-loop control strategy, after obtaining the fixed DC voltage control mode (mode 1) or the fixed active power control mode (mode 2) of the outer loop, and combining the fixed reactive power control mode, the given values ​​of the positive-sequence active power and the positive-sequence reactive power can be automatically determined, thereby effectively controlling the behavior of the power electronic equipment, so that it can not only meet the requirements of the outer-loop control strategy, but also maintain the stability and reliability of the system. In this example, when the outer-loop controller adopts the grid-following control, the positive-sequence power command value is used as the input of the command calculation strategy by adopting the command calculation strategy for converting the command value; and the positive-sequence dq-axis current command value is used as the output of the command calculation strategy. Specifically, the execution logic of the command calculation strategy may include:

[0088] According to the acquired positive sequence voltage d-axis acquisition value and positive sequence voltage q-axis acquisition value of the power electronic equipment, the calculation formula is used: Calculate the initial intermediate limiting variable; where A represents the initial intermediate limiting variable; u d Indicates the d-axis acquisition value of the positive sequence voltage; u q Indicates the q-axis acquisition value of the positive sequence voltage;

[0089] When the initial intermediate limiting variable is less than or equal to a preset limiting margin (for example, represented by Y), the limiting margin Y is used as the updated intermediate limiting variable;

[0090] When the initial intermediate restriction variable is greater than the restriction margin Y, the initial intermediate restriction variable is used as the updated intermediate restriction variable.

[0091] In this implementation, when designing the outer loop controller of the power electronic equipment, it is divided into positive-sequence outer loop control and negative-sequence outer loop control. The corresponding positive-sequence outer loop control has the possibility of being obtained by calculating the active power and the reactive power. Therefore, the present invention focuses on the design of the positive-sequence outer loop control part. When performing the positive-sequence outer loop control, the optional operating mode is the grid-following control mode or the grid-forming control mode; when the grid-following control mode is adopted, the output of the above-mentioned instruction calculation strategy is used as the input of the grid-following control mode of the inner loop controller; when the grid-forming control mode is adopted, the output under this control mode is directly used as the input of the inner loop controller.

[0092] In order to effectively control the power electronic equipment, the structures of the outer loop controller and the inner loop controller are set respectively. The output of the outer loop controller is the positive-sequence dq-axis current command value and the negative-sequence dq-axis current command value. After obtaining the output of the outer loop controller, the inner loop controller will be further designed, and the positive-sequence dq-axis current command value and the negative-sequence dq-axis current command value will be used as the input of the inner loop controller. The structure of the inner loop controller includes three parts: a positive-sequence inner loop controller, a negative-sequence inner loop controller and a dq / abc coordinate system transformation.

[0093] In one implementation, the process of limiting the positive-sequence dq-axis current command value by the inner loop controller of the power electronic equipment in the above step 2 to obtain the positive-sequence voltage three-phase command value may include:

[0094] The positive-sequence d-axis current command value is limited by an inner-loop controller of the power electronic equipment to obtain a positive-sequence d-axis current command value after limiting.

[0095] The positive-sequence q-axis current command value is limited by the inner-loop controller to obtain the positive-sequence q-axis current command value after limiting;

[0096] According to the positive-sequence d-axis current command value after limiting, the positive-sequence voltage d-axis command value is output through the proportional-integral controller;

[0097] According to the positive-sequence q-axis current command value after limiting, the positive-sequence voltage q-axis command value is output through the proportional-integral controller;

[0098] According to the positive-sequence voltage d-axis command value and the positive-sequence voltage q-axis command value, the positive-sequence voltage three-phase command value is obtained through the coordinate system transformation in the inner loop controller.

[0099] In this implementation, after obtaining the positive-sequence d-axis current command value and the positive-sequence q-axis current command value output by the outer-loop controller, the positive-sequence inner-loop controller is designed. First, the positive-sequence d-axis current command value and the positive-sequence q-axis current command value are limited. Secondly, the positive-sequence controller based on the PI controller is set to output the positive-sequence voltage d-axis and q-axis command values, and then the dq to abc coordinate system is transformed to form the command value of the positive-sequence voltage abc coordinate system. Through the design of the positive-sequence inner-loop controller, the optimal limit value is set to achieve the current command during the corresponding power transmission, and stable current control is achieved. The system can better adapt to different operating conditions, such as load changes or changes in grid conditions.

[0100] In one implementation, the process of obtaining the negative-sequence voltage three-phase command value through the inner loop controller according to the negative-sequence dq-axis current command value in the above step 3 may include:

[0101] The negative-sequence dq axis current command value is controlled by a PI controller in the inner loop controller, and a negative-sequence voltage dq axis command command value is output, namely, a negative-sequence d axis voltage command value and a negative-sequence q axis voltage command value. These command values ​​are used to control the voltage output by the power electronic equipment to achieve a desired negative-sequence current;

[0102] In order to convert the negative sequence voltage dq axis command value into the corresponding three-phase voltage command value, coordinate transformation is required, which is usually achieved through the inverse transformation of Clarke Transform or Park Transform, and finally the three-phase command value of negative sequence voltage is obtained. These command values ​​can be used to control the output of negative sequence voltage by power electronic equipment to meet the control requirements of the system. Through this series of steps, it can be ensured that the power electronic equipment can effectively control the negative sequence current and meet the control requirements of the system. This process is very important for improving the stability and performance of the system, especially in the case of dealing with unbalanced loads or grid disturbances.

[0103] In view of the problem that the positive-sequence current is obtained through the positive-sequence component of the voltage during the low voltage ride-through process of the anti-fluctuation power electronic equipment in the prior art, which is prone to fluctuation deviation, the present invention proposes a low voltage ride-through control method for the anti-fluctuation power electronic equipment. The positive-sequence dq-axis current command value is limited by the positive-sequence inner-loop controller, which can avoid system instability caused by excessive current command value, realize the correction of the positive-sequence dq-axis current command in the power transmission process, realize stable current control, and thus reduce voltage fluctuation.

[0104] Embodiment 2:

[0105] Based on the same inventive concept, the present invention also provides a low voltage ride-through control system for power electronic equipment to prevent fluctuations, the structural composition diagram is as follows: Figure 3 As shown, including:

[0106] An outer loop output module, used for outputting a positive sequence dq axis current command value and a negative sequence dq axis current command value of the power electronic equipment through an outer loop controller of the power electronic equipment;

[0107] A positive sequence inner loop output module is used to limit the positive sequence dq axis current command value through the inner loop controller of the power electronic equipment to obtain the positive sequence voltage three-phase command value;

[0108] The negative sequence inner loop output module is used to obtain the negative sequence voltage three-phase command value through the inner loop controller according to the negative sequence dq axis current reference value;

[0109] The low voltage ride through control module is used to perform low voltage ride through control on power electronic equipment according to the positive sequence voltage three-phase command value and the negative sequence voltage three-phase command value.

[0110] In a possible implementation, the outer loop output module may include:

[0111] A grid-following control unit, used for calculating the positive-sequence dq-axis current command value of the power electronic equipment by adopting a command calculation strategy according to the acquired positive-sequence power command value of the power electronic equipment when the outer-loop controller of the power electronic equipment is a positive-sequence outer-loop controller and the operation mode of the outer-loop controller is grid-following control;

[0112] A network control unit, used for outputting the positive sequence dq axis current command value of the power electronic equipment through the outer loop controller when the outer loop controller is a positive sequence outer loop controller and the operation mode of the outer loop controller is network type control;

[0113] The negative-sequence control unit is used to output the negative-sequence dq-axis current command value of the power electronic equipment through the outer loop controller when the outer loop controller is a negative-sequence outer loop controller.

[0114] In this implementation, the positive-sequence power command value in the grid-following control unit may include: a positive-sequence active power command value and a positive-sequence reactive power command value;

[0115] The positive sequence dq axis current command value may include: a positive sequence d axis current command value and a positive sequence q axis current command value;

[0116] The negative-sequence dq-axis current command value may include: a negative-sequence d-axis current command value and a negative-sequence q-axis current command value.

[0117] For example, the calculation formula corresponding to the instruction calculation strategy in the above-mentioned network control unit is as follows:

[0118]

[0119] Among them, i d Indicates the positive sequence d-axis current command value; i q Indicates the positive sequence q-axis current command value; u d Indicates the positive sequence voltage d-axis acquisition value; p ′ Indicates the positive sequence active power command value; u q Indicates the q-axis acquisition value of the positive sequence voltage; q ′ represents the positive sequence reactive power command value; A represents the updated intermediate limit variable.

[0120] In this implementation, the updating process of the intermediate limiting variable A in the network control unit is as follows:

[0121] Calculate the initial intermediate limiting variable according to the acquired positive-sequence voltage d-axis acquisition value and the positive-sequence voltage q-axis acquisition value of the power electronic equipment;

[0122] When the initial intermediate restriction variable is less than or equal to the preset restriction margin, the restriction margin is used as the updated intermediate restriction variable;

[0123] When the initial intermediate restriction variable is greater than the restriction margin, the initial intermediate restriction variable is used as the updated intermediate restriction variable.

[0124] Optionally, the calculation formula corresponding to the initial intermediate limit variable in the network control unit is as follows:

[0125]

[0126] Where A represents the initial intermediate restriction variable; u d Indicates the d-axis acquisition value of the positive sequence voltage; u q Indicates the q-axis sampled value of the positive sequence voltage.

[0127] Optional, positive sequence inner loop output module, including:

[0128] The d-axis limiting unit is used to limit the positive-sequence d-axis current command value through the inner loop controller of the power electronic equipment to obtain the positive-sequence d-axis current command value after limiting.

[0129] The q-axis limiting unit is used to limit the positive-sequence q-axis current command value through the inner loop controller to obtain the positive-sequence q-axis current command value after limiting;

[0130] A d-axis command value output unit is used to output a positive-sequence voltage d-axis command value through a proportional-integral controller according to the positive-sequence d-axis current command value after limiting;

[0131] The q-axis command value output unit is used to output the positive-sequence voltage q-axis command value through a proportional-integral controller according to the positive-sequence q-axis current command value after limiting;

[0132] The coordinate system conversion unit is used to obtain the positive sequence voltage three-phase command value through the coordinate system transformation in the inner loop controller according to the positive sequence voltage d-axis command value and the positive sequence voltage q-axis command value.

[0133] In the present invention, a system suitable for different structures is realized through a series of modular designs. The system can achieve closed-loop, reliable and efficient execution through collection, analysis and control.

[0134] Embodiment 3:

[0135] The present invention also provides an electronic device, which may be a computer device, a single-chip device, an intelligent mobile device, etc. Figure 4As shown, the electronic device 400 in this embodiment includes a processor 401 and a memory 402. The processor 401 is electrically connected to the memory 402. The processor 401 is the control center of the terminal 400, and uses various interfaces and lines to connect various parts of the entire terminal, and executes various functions of the terminal and processes data by running or calling computer programs stored in the memory 402, and calling data stored in the memory 402, so as to monitor the terminal as a whole.

[0136] In this embodiment, the processor 401 in the electronic device 400 will load the instructions corresponding to the processes of one or more computer programs into the memory 402 according to the following steps, and the processor 401 will run the computer program stored in the memory 402 to achieve various functions: set the structure of the outer loop controller of the power electronic equipment, and use the positive-sequence active power command value and the reactive power command value as output; set the structure of the inner loop controller, calculate the abc command value of the positive-sequence current according to the positive-sequence active power command value and the reactive power command value, and calculate the negative-sequence abc command value according to the negative-sequence current command value; set the specific implementation method of the outer loop calculation; perform input and output settings of the command calculation strategy in the positive-sequence current command calculation module; set the internal control strategy of the command calculation strategy; and design the positive-sequence current inner loop controller.

[0137] The memory 402 may be used to store computer programs and data. The computer programs stored in the memory 402 include instructions that can be executed in the processor. The computer programs may constitute various functional modules. The processor 401 executes various functional applications and data processing by calling the computer programs stored in the memory 402.

[0138] Embodiment 4:

[0139] Based on the same inventive concept, the present invention also provides a readable storage medium, specifically an electronic device readable storage medium (Memory), which is a memory device in an electronic device for storing programs and data. It can be understood that the storage medium here can include both built-in storage media in electronic devices and extended storage media supported by electronic devices. The storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more execution programs (including program codes). It should be noted that the storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor loads and executes one or more instructions stored in the storage medium, which can implement the steps of a low voltage ride-through control method for power electronic equipment with anti-fluctuation in the above embodiment.

[0140] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0141] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0142] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0143] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the application, but these changes, modifications or equivalent substitutions are all within the protection scope of the claims to be approved.

Claims

1. A low voltage ride-through control method for power electronic equipment to prevent fluctuations, characterized in that: include: Outputting a positive-sequence dq-axis current command value and a negative-sequence dq-axis current command value of the power electronic equipment through an outer loop controller of the power electronic equipment; The positive-sequence dq-axis current command value is limited by the inner loop controller of the power electronic equipment to obtain a positive-sequence voltage three-phase command value; According to the negative-sequence dq-axis current command value, a negative-sequence voltage three-phase command value is obtained through the inner loop controller; According to the positive-sequence voltage three-phase command value and the negative-sequence voltage three-phase command value, low voltage ride-through control is performed on the power electronic equipment.

2. The method according to claim 1, characterized in that The outputting of the positive-sequence dq-axis current command value and the negative-sequence dq-axis current command value of the power electronic equipment through the outer loop controller of the power electronic equipment comprises: When the outer loop controller of the power electronic equipment is a positive-sequence outer loop controller, and the operation mode of the outer loop controller is grid-following control, according to the acquired positive-sequence power command value of the power electronic equipment, an command calculation strategy is adopted to calculate the positive-sequence dq-axis current command value of the power electronic equipment; When the outer loop controller is a positive-sequence outer loop controller, and the operation mode of the outer loop controller is grid-type control, the positive-sequence dq-axis current command value of the power electronic equipment is output through the outer loop controller; When the outer loop controller is a negative-sequence outer loop controller, the negative-sequence dq-axis current command value of the power electronic equipment is output through the outer loop controller.

3. The method according to claim 2, characterized in that The positive-sequence power command value includes: a positive-sequence active power command value and a positive-sequence reactive power command value; The positive-sequence dq-axis current command value comprises: a positive-sequence d-axis current command value and a positive-sequence q-axis current command value; The negative-sequence dq-axis current command value includes: a negative-sequence d-axis current command value and a negative-sequence q-axis current command value.

4. The method according to claim 3, characterized in that The calculation formula corresponding to the instruction calculation strategy is as follows: Among them, i d Indicates the positive sequence d-axis current command value; i q Indicates the positive sequence q-axis current command value; u d Indicates the positive sequence voltage d-axis acquisition value; p ′ Indicates the positive sequence active power command value; u q Indicates the q-axis acquisition value of the positive sequence voltage; q ′ represents the positive sequence reactive power command value; A represents the updated intermediate limit variable.

5. The method according to claim 4, characterized in that The updating process of the intermediate restriction variable A is as follows: Calculating an initial intermediate limiting variable according to the acquired positive-sequence voltage d-axis acquisition value and the positive-sequence voltage q-axis acquisition value of the power electronic equipment; When the initial intermediate limiting variable is less than or equal to a preset limiting margin, taking the limiting margin as an updated intermediate limiting variable; When the initial intermediate limiting variable is greater than the limiting margin, the initial intermediate limiting variable is used as the updated intermediate limiting variable.

6. The method according to claim 5, characterized in that The calculation formula corresponding to the initial intermediate restriction variable is as follows: Where A represents the initial intermediate restriction variable; u d Indicates the d-axis acquisition value of the positive sequence voltage; u q Indicates the q-axis acquisition value of the positive sequence voltage.

7. The method according to claim 3, characterized in that The inner loop controller of the power electronic equipment limits the positive-sequence dq-axis current command value to obtain a positive-sequence voltage three-phase command value, including: Limiting the positive-sequence d-axis current command value by an inner-loop controller of the power electronic equipment to obtain a positive-sequence d-axis current command value after limiting; By means of the inner loop controller, the positive-sequence q-axis current command value is limited to obtain the positive-sequence q-axis current command value after limiting; According to the positive-sequence d-axis current command value after the limiting, the positive-sequence voltage d-axis command value is output through the proportional-integral controller; According to the positive-sequence q-axis current command value after the limiting, the positive-sequence voltage q-axis command value is output through the proportional-integral controller; According to the positive-sequence voltage d-axis command value and the positive-sequence voltage q-axis command value, the positive-sequence voltage three-phase command value is obtained through the coordinate system transformation in the inner loop controller.

8. A low voltage ride-through control system for power electronic equipment to prevent fluctuations, characterized in that: include: An outer loop output module, used for outputting a positive sequence dq axis current command value and a negative sequence dq axis current command value of the power electronic equipment through an outer loop controller of the power electronic equipment; A positive sequence inner loop output module, used to limit the positive sequence dq axis current command value through the inner loop controller of the power electronic equipment to obtain a positive sequence voltage three-phase command value; A negative-sequence inner loop output module, used to obtain a negative-sequence voltage three-phase command value through the inner loop controller according to the negative-sequence dq-axis current command value; A low voltage ride through control module is used to perform low voltage ride through control on the power electronic equipment according to the positive sequence voltage three-phase command value and the negative sequence voltage three-phase command value.

9. The system according to claim 8, characterized in that The outer ring output module comprises: A grid-following control unit, configured to calculate the positive-sequence dq-axis current command value of the power electronic equipment by adopting a command calculation strategy according to the acquired positive-sequence power command value of the power electronic equipment when the outer-loop controller of the power electronic equipment is a positive-sequence outer-loop controller and the operation mode of the outer-loop controller is grid-following control; A network control unit, configured to output the positive-sequence dq-axis current command value of the power electronic equipment through the outer loop controller when the outer loop controller is a positive-sequence outer loop controller and the operation mode of the outer loop controller is network-type control; A negative-sequence control unit is used to output the negative-sequence dq-axis current command value of the power electronic equipment through the outer loop controller when the outer loop controller is a negative-sequence outer loop controller.

10. The system according to claim 9, characterized in that The positive-sequence power command value in the grid-following control unit includes: a positive-sequence active power command value and a positive-sequence reactive power command value; The positive-sequence dq-axis current command value comprises: a positive-sequence d-axis current command value and a positive-sequence q-axis current command value; The negative-sequence dq-axis current command value includes: a negative-sequence d-axis current command value and a negative-sequence q-axis current command value.

11. An electronic device, characterized in that: include: at least one processor and memory; The memory and the processor are connected via a bus; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, a low voltage ride-through control method for power electronic equipment against fluctuations as claimed in any one of claims 1 to 7 is implemented.

12. A computing device readable storage medium, characterized in that: An execution program is stored thereon, and when the execution program is executed, a low voltage ride-through control method for power electronic equipment against fluctuations as described in any one of claims 1 to 7 is implemented.

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