High-reliability power electronic equipment low voltage ride through control method and system

Abstract

The invention provides a high-reliability power electronic equipment low voltage ride through control method and system, and the method comprises the steps: setting an integral maintenance control strategy for an outer ring controller based on the positive and negative sequence dq axis current instruction values of power electronic equipment when the operation mode of the outer ring controller of the power electronic equipment is network construction type control, outputting positive and negative sequence dq axis current instruction values after integral holding control; outputting a corresponding voltage instruction value through an inner ring controller of the power electronic equipment on the basis of the positive and negative sequence dq axis current instruction values after integral holding control; performing low voltage ride through control on the power electronic equipment according to the voltage instruction value; in the low voltage ride-through process of the power electronic equipment, by setting the integral keeping control strategy for the outer ring controller of the power electronic equipment, the current instruction value can rapidly return to the normal level after the fault is recovered, and the ride-through speed of the fault and the success rate of the fault ride-through are improved.

Description

Technical Field

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

[0002] At present, power electronic equipment may encounter faults due to various reasons during operation. When these faults occur, if there is no fault ride-through capability, the power electronic equipment may stop running or fail, thus affecting the stability and reliability of the entire power system. Therefore, in order to ensure that power electronic equipment can operate continuously and stably when encountering faults, the equipment needs to have a certain fault ride-through capability. First, power electronic equipment with fault ride-through capability can respond to faults quickly and take appropriate measures. In this way, even if a fault occurs, the damage to the equipment can be reduced through the equipment's rapid response and self-protection mechanism. Secondly, equipment with fault ride-through capability can prevent chain reactions in the power grid. When a device fails, if it is not handled in time, it may affect the normal operation of other devices. Equipment with fault ride-through capability can take appropriate measures to prevent such chain reactions when a fault occurs, thereby ensuring the stability and reliability of the entire power system. In addition, equipment with fault ride-through capability can also reduce the impact on the power grid. When equipment fails, if there are no appropriate countermeasures, it may cause the voltage and frequency of the power grid to fluctuate, thus affecting the operational stability of the entire power grid. Equipment with fault ride-through capability can take appropriate measures to reduce the impact on the power grid and ensure the stable operation of the power grid when a fault occurs. In short, it is very important for power electronic equipment to have fault ride-through capability, which can ensure the continuous and stable operation of the equipment, reduce the impact on the power grid and the occurrence of chain reactions, and improve the stability and reliability of the entire power system.

[0003] The fault-crossing process of existing power electronic equipment often finds it difficult to quickly recover to the pre-fault state. The reason for this is that in many cases, the control outer loop will produce a long-term integral retention when a fault occurs, resulting in the current control command being difficult to recover to a normal level after the fault is recovered, which in turn makes it difficult to recover from the impact of the fault. Summary of the invention

[0004] In order to solve the problem that during the fault ride-through process of the existing power electronic equipment, the integral value is kept in a holding state for a long time, resulting in the difficulty of quickly recovering to the state before the fault after the fault is recovered, the present invention proposes a high-reliability low voltage ride-through control method for power electronic equipment, comprising:

[0005] When the operation mode of the outer loop controller of the power electronic equipment is grid-type control, an integral holding control strategy is set for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment, and the positive and negative sequence dq axis current command values ​​after integral holding control are output;

[0006] Based on the positive and negative sequence dq axis current command values ​​after the integral hold control, outputting corresponding voltage command values ​​through the inner loop controller of the power electronic equipment;

[0007] According to the voltage command value, low voltage ride-through control is performed on the power electronic equipment.

[0008] Optionally, the positive-sequence and negative-sequence dq-axis current command values ​​include: a positive-sequence dq-axis current command value and a negative-sequence dq-axis current command value;

[0009] 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;

[0010] 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;

[0011] The voltage command value corresponding to the positive-sequence d-axis current command value is the positive-sequence d-axis voltage command value;

[0012] The voltage command value corresponding to the positive-sequence q-axis current command value is the positive-sequence q-axis voltage command value;

[0013] The voltage command value corresponding to the negative-sequence d-axis current command value is a negative-sequence d-axis voltage command value;

[0014] The voltage command value corresponding to the negative-sequence q-axis current command value is a negative-sequence q-axis voltage command value.

[0015] Optionally, the step of setting an integral hold control strategy for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment, and outputting the positive and negative sequence dq axis current command values ​​after integral hold control, comprises:

[0016] Obtaining positive and negative sequence dq axis current command values ​​of the power electronic equipment;

[0017] The positive and negative sequence dq axis current command values ​​are limited by a hysteresis comparator to obtain the limited positive and negative sequence dq axis current command values;

[0018] When the positive and negative sequence dq axis current command values ​​after the limitation do not reach the upper limit of the hysteresis comparator, a saturation exit command is issued;

[0019] When the positive and negative sequence dq axis current command values ​​after limitation reach the upper limit of the hysteresis comparator, a saturation command is issued; and according to the saturation command, an integral hold control strategy is set for the outer loop controller to output the positive and negative sequence dq axis current command values ​​after integral hold control.

[0020] Optionally, setting an integral hold control strategy for the outer loop controller includes:

[0021] Obtaining the integral value of the outer loop controller according to the positive and negative sequence dq axis current command values ​​after the limitation;

[0022] The integral value of the outer loop controller is maintained at the current value until the saturation exit instruction is received, and the integral value of the outer loop controller is restored.

[0023] Optionally, the method further includes:

[0024] When the outer loop controller of the power electronic equipment is a positive sequence outer loop controller, and the operation mode of the positive sequence outer loop controller is grid-following control, obtaining the AC voltage dq axis measured value and the power command value of the power electronic equipment;

[0025] Calculating the positive-sequence dq-axis current command value output by the positive-sequence outer-loop controller under grid-following control according to the measured value of the AC voltage dq-axis and the power command value of the power electronic equipment;

[0026] Based on the positive-sequence dq-axis current command value output by the positive-sequence outer-loop controller under grid-following control, the corresponding voltage command value is output through the inner-loop controller of the power electronic equipment.

[0027] Optionally, the AC voltage dq axis measured value includes: the AC voltage d axis measured value and the AC voltage q axis measured value;

[0028] The power command value includes: an active power command value and a reactive power command value.

[0029] Optionally, the calculation formula corresponding to the positive-sequence d-axis current command value output by the positive-sequence outer loop controller under grid-following control is as follows:

[0030]

[0031] The calculation formula corresponding to the positive-sequence q-axis current command value output by the positive-sequence outer loop controller under grid-following control is as follows:

[0032]

[0033] in, Indicates the positive sequence d-axis current command value; Indicates the positive sequence q-axis current command value; ud Indicates the measured value of the AC voltage d axis; u q represents the actual measured value of the AC voltage q axis; p represents the active power command value; q′ represents the reactive power command value.

[0034] Optionally, the method further includes:

[0035] When the outer loop controller is a negative-sequence outer loop controller, and the operation mode of the negative-sequence outer loop controller is grid-following control, the negative-sequence dq-axis current command value of the power electronic equipment is set to a preset value.

[0036] Optionally, the power electronic equipment includes one or more of the following: a VSC converter, an energy storage device, a reactive power compensation device and a doubly-fed wind generator.

[0037] Optionally, the positive and negative sequence dq axis current command values ​​of the power electronic equipment are obtained by Laplace transforming the transfer function of the grid-type controller in the outer loop controller.

[0038] Based on the same inventive concept, the present invention also provides a high-reliability low voltage ride-through control system for power electronic equipment, comprising:

[0039] The outer loop control module is used to set an integral holding control strategy for the outer loop controller when the operation mode of the outer loop controller of the power electronic equipment is grid-type control, based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment, and output the positive and negative sequence dq axis current command values ​​after integral holding control;

[0040] Inner loop control module: used for outputting corresponding voltage command values ​​through the inner loop controller of the power electronic equipment based on the positive and negative sequence dq axis current command values ​​after the integral hold control;

[0041] Voltage ride-through control module: used to perform low voltage ride-through control on the power electronic equipment according to the voltage command value.

[0042] Optionally, the positive and negative sequence dq axis current command values ​​in the outer loop control module include: a positive sequence dq axis current command value and a negative sequence dq axis current command value;

[0043] 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;

[0044] 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;

[0045] The voltage command value corresponding to the positive-sequence d-axis current command value is the positive-sequence d-axis voltage command value;

[0046] The voltage command value corresponding to the positive-sequence q-axis current command value is the positive-sequence q-axis voltage command value;

[0047] The voltage command value corresponding to the negative-sequence d-axis current command value is a negative-sequence d-axis voltage command value;

[0048] The voltage command value corresponding to the negative-sequence q-axis current command value is a negative-sequence q-axis voltage command value.

[0049] Optionally, the outer loop control module is specifically used to:

[0050] Obtaining positive and negative sequence dq axis current command values ​​of the power electronic equipment;

[0051] The positive and negative sequence dq axis current command values ​​are limited by a hysteresis comparator to obtain the limited positive and negative sequence dq axis current command values;

[0052] When the positive and negative sequence dq axis current command values ​​after the limitation do not reach the upper limit of the hysteresis comparator, a saturation exit command is issued;

[0053] When the positive and negative sequence dq axis current command values ​​after limitation reach the upper limit of the hysteresis comparator, a saturation command is issued; and according to the saturation command, an integral hold control strategy is set for the outer loop controller to output the positive and negative sequence dq axis current command values ​​after integral hold control.

[0054] Optionally, the outer loop control module sets an integral hold control strategy for the outer loop controller, including:

[0055] Obtaining the integral value of the outer loop controller according to the positive and negative sequence dq axis current command values ​​after the limitation;

[0056] The integral value of the outer loop controller is maintained at the current value until the saturation exit instruction is received, and the integral value of the outer loop controller is restored.

[0057] Optionally, the outer loop control module is further used for:

[0058] When the outer loop controller of the power electronic equipment is a positive sequence outer loop controller, and the operation mode of the positive sequence outer loop controller is grid-following control, obtaining the AC voltage dq axis measured value and the power command value of the power electronic equipment;

[0059] Calculating the positive-sequence dq-axis current command value output by the positive-sequence outer-loop controller under grid-following control according to the measured value of the AC voltage dq-axis and the power command value of the power electronic equipment;

[0060] Based on the positive-sequence dq-axis current command value output by the positive-sequence outer-loop controller under grid-following control, the corresponding voltage command value is output through the inner-loop controller of the power electronic equipment.

[0061] Optionally, the AC voltage dq axis measured value in the outer loop control module includes: the AC voltage d axis measured value and the AC voltage q axis measured value;

[0062] The power command value includes: an active power command value and a reactive power command value.

[0063] Optionally, the calculation formula corresponding to the positive-sequence d-axis current command value output by the positive-sequence outer-loop controller in the outer-loop control module under the grid-following control is as follows:

[0064]

[0065] The calculation formula corresponding to the positive-sequence q-axis current command value output by the positive-sequence outer loop controller under grid-following control is as follows:

[0066]

[0067] in, Indicates the positive sequence d-axis current command value; Indicates the positive sequence q-axis current command value; u d Indicates the measured value of the AC voltage d axis; u q represents the actual measured value of the AC voltage q axis; p represents the active power command value; q′ represents the reactive power command value.

[0068] Optionally, the outer loop control module is further used to:

[0069] When the outer loop controller is a negative-sequence outer loop controller, and the operation mode of the negative-sequence outer loop controller is grid-following control, the negative-sequence dq-axis current command value of the power electronic equipment is set to a preset value.

[0070] Optionally, the power electronic equipment in the outer loop control module includes one or more of the following: a VSC converter, an energy storage device, a reactive power compensation device and a doubly-fed wind turbine generator.

[0071] Optionally, the positive and negative sequence dq axis current command values ​​of the power electronic equipment in the outer loop control module are obtained by Laplace transforming the transfer function of the grid-type controller in the outer loop controller.

[0072] 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;

[0073] The memory is used to store one or more programs;

[0074] When the one or more programs are executed by the at least one processor, the high-reliability low voltage ride-through control method for power electronic equipment as described above is implemented.

[0075] 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 high-reliability power electronic equipment low voltage ride-through control method as described above is implemented.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The present invention provides a high-reliability low voltage ride-through control method and system for power electronic equipment, comprising: when the operation mode of the outer loop controller of the power electronic equipment is grid-type control, based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment, setting an integral holding control strategy for the outer loop controller, and outputting the positive and negative sequence dq axis current command values ​​after integral holding control; based on the positive and negative sequence dq axis current command values ​​after integral holding control, outputting corresponding voltage command values ​​through the inner loop controller of the power electronic equipment; performing low voltage ride-through control on the power electronic equipment according to the voltage command value; in the process of low voltage ride-through of the power electronic equipment, the present application can realize the rapid return of the current command value to a normal level after fault recovery by setting an integral holding control strategy for the outer loop controller of the power electronic equipment, which is beneficial to improving the fault ride-through speed and the success rate of fault ride-through. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 It is a flow chart of a low voltage ride through control method for high reliability power electronic equipment according to an embodiment of the present invention;

[0079] Figure 2 It is a schematic diagram of an architecture of setting a control mode of a power electronic equipment as a dual closed-loop control in a low voltage ride-through control method for a high-reliability power electronic equipment according to an embodiment of the present invention;

[0080] Figure 3 It is a schematic diagram of the output contents of an outer loop controller in a low voltage ride-through control method for high reliability power electronic equipment according to an embodiment of the present invention;

[0081] Figure 4 It is a schematic diagram of an outer loop control framework in a low voltage ride-through control method for high reliability power electronic equipment according to an embodiment of the present invention;

[0082] Figure 5 It is a schematic diagram of an inner loop control framework in a low voltage ride through control method for high reliability power electronic equipment according to an embodiment of the present invention;

[0083] Figure 6This is a schematic diagram of the structure of a low voltage ride-through control system for high-reliability power electronic equipment according to an embodiment of the present invention;

[0084] Figure 7 A schematic diagram of the structure of an electronic device provided by the present invention;

[0085] Figure 8 The present invention provides an overall structural diagram of an electronic device. DETAILED DESCRIPTION

[0086] The present invention provides a high-reliability low voltage ride-through control method and system for power electronic equipment. The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings.

[0087] Embodiment 1:

[0088] A high reliability low voltage ride through control method for power electronic equipment, the flow chart is as follows Figure 1 As shown, including:

[0089] Step 1: When the operation mode of the outer loop controller of the power electronic equipment is grid-type control, an integral holding control strategy is set for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment, and the positive and negative sequence dq axis current command values ​​after integral holding control are output;

[0090] Step 2: Based on the positive and negative sequence dq axis current command values ​​after integral hold control, the inner loop controller of the power electronic equipment outputs the corresponding voltage command values;

[0091] Step 3: Perform low voltage ride-through control on the power electronic equipment according to the voltage command value.

[0092] Generally, the control modes for power electronic equipment can include single closed-loop control and dual closed-loop control. Single closed-loop control has only one control loop, usually voltage control or current control, and is suitable for occasions with low requirements for dynamic performance (such as simple switching power supplies). However, since there is only one control loop, the dynamic response speed of the system is slow, and since it is difficult to achieve decoupling control, the control performance is limited. During the fault ride-through process of the power electronic equipment, it may not be able to quickly recover to the pre-fault state.

[0093] Therefore, in response to the above-mentioned problems existing in single closed-loop control, the present invention sets the control mode of the power electronic equipment to dual closed-loop control, and in order to adapt to the control of different types of power electronic equipment, the above-mentioned power electronic equipment may include one or more of the following: voltage source converter (Voltage Source Converter, also known as VSC converter), energy storage device, reactive power compensation device and doubly fed wind turbine generator. By setting an integral holding control strategy for the power electronic equipment, a non-long-term self-recovery integral environment is constructed to achieve rapid isolation and recovery of the corresponding fault state and achieve the effect of rapid fault crossing.

[0094] In one implementation, the above-mentioned dual closed-loop control includes outer loop control (implemented by an outer loop controller) and inner loop control (implemented by an inner loop controller), the outer loop control specifically includes positive sequence outer loop control and negative sequence outer loop control, and the inner loop control specifically includes positive sequence inner loop control and negative sequence inner loop control; when the outer loop control is performed on the power electronic equipment, the operation mode of the outer loop controller can adopt one of the grid-building type control and the grid-following type control; when the inner loop control is performed on the power electronic equipment, the inner loop controller can adopt constant current control;

[0095] In this implementation, if Figure 2As shown in the figure, when the power electronic equipment is subjected to low voltage ride-through control, the selection of the outer loop control and inner loop control operation mode is crucial. The outer loop control determines the overall operation characteristics of the power electronic equipment, while the inner loop control is responsible for achieving more precise current regulation. There are two main types of outer loop control operation modes: grid-building control and grid-following control. When the grid-building control mode is adopted, voltage-frequency control (Voltage-Frequency Control, also known as VF control) can be used first. VF control focuses on the control of voltage and frequency. Its control given values ​​are voltage and frequency. It is suitable for scenarios that need to maintain specific voltage and frequency, such as microgrids or island operation. When the outer loop control operation mode adopts the grid-following control mode, power control (Power Control, also known as PQ control) can be used first. The control given values ​​of PQ control are active power and reactive power. Therefore, it focuses more on the control of active power and reactive power, and is more suitable for systems closely connected to the main power grid to ensure the balance of active and reactive power of the system. The inner loop control of power electronic equipment usually adopts constant current control, which achieves faster and more accurate control response by directly adjusting the current. This control method is crucial to ensure the stable operation of power electronic equipment. Combining the outer loop control and inner loop control mentioned above can form a dual closed-loop control mode, which can adapt to various types of power electronic equipment, such as VSC converters, energy storage systems, reactive power compensation devices and doubly fed wind turbines. Dual closed-loop control combines the voltage / power control of the outer loop and the current control of the inner loop, providing a comprehensive and flexible control method for power electronic equipment to adapt to different grid conditions and operating requirements. In short, the choice of this dual closed-loop control mode enables power electronic equipment to better adapt to various application scenarios and improve the stability and efficiency of the power system.

[0096] During the process of power electronic equipment fault riding, if it is in an integral holding state for a long time, it may cause a continuous accumulation of integral environment. In this process, the limit value may have been reached. If the limit value is reached, continuous integration will cause the integral amount to be too large and difficult to recover to a normal value after the fault is restored. Therefore, the present invention sets an integral holding control strategy when the outer loop controller of the power electronic equipment adopts a grid-type control to achieve rapid recovery of the integral of the power electronic equipment. Specifically, in one implementation method, the process of setting an integral holding control strategy for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment in the above step 1 and outputting the positive and negative sequence dq axis current command values ​​after integral holding control may include:

[0097] Obtain positive and negative sequence dq axis current command values ​​of power electronic equipment;

[0098] The positive and negative sequence dq axis current command values ​​are limited by the hysteresis comparator to obtain the limited positive and negative sequence dq axis current command values;

[0099] When the positive and negative sequence dq axis current command values ​​after limitation do not reach the upper limit of the hysteresis comparator, a saturation exit command is issued;

[0100] When the positive and negative sequence dq axis current command values ​​after limitation reach the upper limit of the hysteresis comparator, a saturation command is issued; and according to the saturation command, an integral hold control strategy is set for the outer loop controller to output the positive and negative sequence dq axis current command values ​​after integral hold control;

[0101] For example, Figure 3 As shown, the above-mentioned positive and negative sequence dq axis current command values ​​include positive sequence dq axis current command values ​​and negative sequence dq axis current command values; the positive sequence dq axis current command values ​​include positive sequence d axis current command values ​​and positive sequence q axis current command values; the negative sequence dq axis current command values ​​include negative sequence d axis current command values ​​and negative sequence q axis current command values; as Figure 4 As shown, when the outer loop controller is a positive-sequence outer loop control, no matter which operation mode the outer loop controller selects (one of the following-grid control mode or the forming-grid control mode), the output of the outer loop controller is a positive-sequence dq-axis current command value; when the outer loop controller is a negative-sequence outer loop control, no matter which operation mode the outer loop controller selects (one of the following-grid control mode or the forming-grid control mode), the outer loop controller outputs a negative-sequence dq-axis current command value accordingly;

[0102] Taking the outer loop controller as the positive-sequence outer loop control as an example, when the outer loop controller adopts the grid-type control method, after the positive-sequence dq-axis current command value is obtained, the positive-sequence dq-axis current command value is limited by the hysteresis comparator. When the upper limit of the hysteresis comparator of the positive-sequence current is reached, the positive-sequence saturation command is continuously issued, which can smoothly control the current rise, reduce the current mutation, and improve the stability of the power system; when the upper limit of the hysteresis comparator of the positive-sequence current is not reached, the positive-sequence saturation exit command is issued.

[0103] Taking the outer loop controller as a negative-sequence outer loop control as an example, when the outer loop controller still adopts a meshed control method, after the negative-sequence dq-axis current command value is obtained, the negative-sequence dq-axis current command value is limited by the hysteresis comparator. When the upper limit of the hysteresis comparator of the negative-sequence current is reached, the negative-sequence saturation command is continuously issued. When the upper limit of the hysteresis comparator of the negative-sequence current is not reached, the negative-sequence saturation exit command is issued.

[0104] In the present invention, by setting the upper limit of the hysteresis comparator, it is possible to avoid excessive increase in the current command value, prevent the occurrence of over-modulation, and improve the response speed and stability of the system; by limiting the current not to exceed the maximum value, it is possible to reduce unnecessary energy losses and improve the overall efficiency of the power system; by reasonably setting the upper limit and exit command of the hysteresis comparator, it is possible to improve the dynamic performance of the power electronic converter and improve the response speed and stability of the system.

[0105] In this implementation, the positive-sequence dq-axis current command value and the negative-sequence dq-axis current command value of the power electronic equipment are obtained by Laplace transforming the transfer function of the grid-type controller in the outer loop controller;

[0106] For example, the transfer function of the above-mentioned network controller corresponds to the following expression:

[0107]

[0108] Among them, G(S1) represents the transfer function corresponding to the Laplace operator S1; Indicates that the Laplace operator is the proportional coefficient corresponding to S1; Indicates that the Laplace operator is the integral coefficient corresponding to S1; S1 is the Laplace operator; when the outer loop control is the positive sequence outer loop control, the positive sequence dq axis current command value is obtained through the output of the positive sequence current grid controller; and the input of the positive sequence current grid controller is and in, The d-axis component of the measured value of the positive sequence of the AC voltage on the grid side (that is, the measured value of the positive sequence d-axis voltage); The q-axis component of the measured value of the positive sequence of the AC voltage on the grid side (i.e., the measured value of the positive sequence q-axis voltage); when the outer loop control is the negative sequence outer loop control, the negative sequence dq-axis current command value is obtained through the output of the negative sequence current grid controller; and the input quantity of the negative sequence current grid controller is and in, The d-axis component of the measured value of the negative sequence AC voltage on the grid side (ie, the actual measured value of the negative sequence d-axis voltage); The q-axis component of the measured value of the negative sequence of the AC voltage on the grid side (that is, the actual measured value of the negative sequence q-axis voltage);

[0109] According to this example, it can be explained that when the outer loop controller adopts the grid-type control of the positive sequence current, the positive sequence dq axis current command value is obtained by Laplace transforming the transfer function of the grid-type controller of the positive sequence current, and the input quantity of the grid-type control is the d-axis and q-axis components of the positive sequence measurement value of the grid-side AC voltage. When the grid-type control strategy is adopted, once the positive sequence dq axis current command value is obtained, the system will limit it through the hysteresis comparator. When the positive sequence dq axis current command value reaches the upper limit of the hysteresis comparator, the system will continue to issue a positive sequence saturation command; when the command value is lower than the upper limit, a positive sequence saturation exit command will be issued. Such a limiting mechanism helps to ensure the stability of the power system and the precise control of the current. When the outer loop controller adopts the grid-type control of negative-sequence current, the negative-sequence dq-axis current command value is obtained by Laplace transforming the transfer function of the grid-type controller of negative-sequence current. Similar to the positive-sequence outer loop control, the input quantity of the grid-type control strategy of negative-sequence current is the d-axis and q-axis components of the negative-sequence measurement value of the grid-side AC voltage. After obtaining the negative-sequence dq-axis current command value, the system will use the hysteresis comparator to limit it again. If the command value of the negative-sequence current reaches the upper limit of the hysteresis comparator, the system will continue to issue negative-sequence saturation commands; if the command value is lower than the upper limit, a negative-sequence saturation exit command will be issued. This limiting mechanism helps to ensure that the negative-sequence current is within the controllable range, thereby maintaining the stable operation of the system.

[0110] In one implementation, the process of setting the integral hold control strategy for the outer loop controller may include:

[0111] According to the positive and negative sequence dq axis current command values ​​after limitation, the integral value of the outer loop controller is obtained;

[0112] The integral value of the outer loop controller is maintained at the current value until a saturation exit command is received, and the integral value of the outer loop controller is restored. When the network control method is adopted, a control command needs to be set in real time, which is to obtain a negative sequence saturation command or a positive sequence saturation command;

[0113] Taking the control instruction to obtain the negative-sequence saturation instruction as an example, the content of setting the integral holding control strategy for the outer loop controller specifically includes: making the integral value of the negative-sequence outer loop controller remain at the current value and no longer increase until the negative-sequence saturation exit instruction is received, then the integral value of the negative-sequence outer loop controller is restored and no longer maintains the current value; that is, when the system issues a negative-sequence saturation instruction, the integral value of the negative-sequence outer loop controller will also be locked at the current value and will no longer increase. In this way, this helps to maintain the stability of the system when the system faces negative-sequence current overload or other related problems. Only when the negative-sequence saturation state is released, that is, after receiving the negative-sequence saturation exit instruction, the integral value of the negative-sequence outer loop controller will resume its normal function. This method of managing the integral value of the outer loop controller through control instructions is very effective under the network control mode.

[0114] Taking the control instruction to obtain the positive-sequence saturation instruction as an example, the content of setting the integral holding control strategy for the outer loop controller specifically includes: making the integral value of the positive-sequence outer loop controller remain at the current value and no longer increase until the positive-sequence saturation exit instruction is received, then the integral value of the positive-sequence outer loop controller is restored and the current value is no longer maintained. That is, when the system issues a positive-sequence saturation instruction, the integral value of the positive-sequence outer loop controller will also be locked at the current value and will no longer increase. This method helps to maintain the stability of the system when the system faces positive-sequence current overload or other related problems. Only when the positive-sequence saturation state is released, that is, after receiving the positive-sequence saturation exit instruction, the integral value of the positive-sequence outer loop controller will resume its normal function. This method of managing the integral value of the outer loop controller through control instructions is very effective under the network control mode.

[0115] In this implementation, the present invention sets an integral holding control strategy for the outer loop controller of the power electronic device when the outer loop controller adopts a meshed control method, and terminates the integral holding method to achieve a rapid return of the current command value to a normal level after fault recovery. This can not only provide stability when the system is close to its operating limit, but also ensure that the controller can make appropriate responses when facing various complex situations, which is conducive to achieving rapid recovery of the integral of the power electronic equipment, improving the fault crossing speed and the success rate of fault crossing, thereby maintaining the normal operation of the system; and by setting real-time control instructions during the integral holding control process, the integral values ​​of the positive-sequence and negative-sequence outer loop controllers can be finely managed, which helps to prevent excessive growth of the controller integral value, thereby providing additional stability when the system is close to its operating limit.

[0116] In one implementation, when the operation mode adopted by the outer loop controller is different, the calculation method and processing method of the positive and negative sequence dq axis current command values ​​are also different:

[0117] Taking the outer loop controller of the power electronic equipment as a positive-sequence outer loop control as an example, and when the operation mode of the positive-sequence outer loop control is grid-following control, the positive-sequence dq-axis current command value is calculated based on the AC voltage dq-axis measured value and the power command value of the power electronic equipment; for example, the AC voltage dq-axis measured value may include: the AC voltage d-axis measured value and the AC voltage q-axis measured value; the power command value may include: the active power command value and the reactive power command value.

[0118] For example, the calculation formula corresponding to the positive-sequence d-axis current command value output by the above-mentioned positive-sequence outer loop controller under grid-following control can be as follows:

[0119]

[0120] For example, the calculation formula corresponding to the positive-sequence q-axis current command value output by the above-mentioned positive-sequence outer loop controller under grid-following control can be as follows:

[0121]

[0122] in, Indicates the positive sequence d-axis current command value; Indicates the positive sequence q-axis current command value; u d Indicates the measured value of the AC voltage d axis; u q represents the actual measured value of the AC voltage q axis; p represents the active power command value; q′ represents the reactive power command value.

[0123] In this example, when the outer loop controller adopts grid-following control, the positive sequence dq axis current command value is calculated by a specific calculation formula based on the d axis measured value and q axis measured value of the AC voltage, the active power command value and the reactive power command value. d and u q It is not zero and the voltage amplitude is limited.

[0124] Take the case where the outer loop controller of the power electronic equipment is a negative-sequence outer loop control, and when the operation mode of the negative-sequence outer loop control is grid-following control, the negative-sequence dq-axis current command value of the power electronic equipment is set to a preset value, preferably set to 0. When performing low voltage ride-through control on power electronic equipment, the processing of negative-sequence current is equally important because it is closely related to the stability and power quality of the system. In this example, the negative-sequence dq-axis current command value is directly set to 0, which means that the power electronic equipment hopes that there will be no negative-sequence current under this control mode. This is to ensure that the power electronic equipment can operate stably during grid voltage imbalance or drop, and minimize the impact on the grid.

[0125] In general, the present invention adopts different methods for calculating the positive and negative sequence dq axis current command values ​​and processing logic according to the different operation modes of the outer loop controller. For the processing of negative sequence current, the grid-following control mode directly sets its command value to 0, while the grid-building control mode calculates the positive and negative sequence dq axis current command values ​​through a special controller and uses a hysteresis comparator to limit them. The choice of these two processing methods depends on the operation mode of the outer loop controller, which aims to ensure that the power electronic equipment can maintain stable and efficient operation in the face of different types of disturbances and faults. The selection and implementation of these control strategies are crucial to ensuring the stable operation and efficient energy conversion of the power electronic system.

[0126] After the outer loop controller outputs the positive and negative sequence dq axis current command values, the positive and negative sequence dq axis current command values ​​need to be current controlled by the inner loop controller of the power electronic equipment (this process can also be expressed as the process of performing the transfer function and output of the inner loop controller according to the output of the outer loop controller), so as to achieve the tracking of the current command value output by the outer loop controller.

[0127] In one implementation, after the outer loop controller outputs the positive and negative sequence dq axis current command values, the inner loop controller of the power electronic equipment outputs the corresponding voltage command values, for example, Figure 5 As shown, the control method of the above-mentioned inner loop controller is similar to that of the outer loop controller, and can also include positive-sequence inner loop control and negative-sequence inner loop control; when the inner loop controller is subjected to positive-sequence inner loop control, a positive-sequence d-axis voltage command value and a positive-sequence q-axis voltage command value can be output; when the inner loop controller is subjected to negative-sequence inner loop control, a negative-sequence d-axis voltage command value and a negative-sequence q-axis voltage command value can be output.

[0128] Taking the positive sequence inner loop control as an example, during the setting of the inner loop controller of the positive sequence current, (positive sequence d-axis current command value), (positive sequence q-axis current command value) is set to a given value; (measured value of positive sequence d-axis current) and (measured value of positive sequence q-axis current), (measured value of positive sequence d-axis voltage) and (measured value of positive sequence q-axis voltage) as input; using the Laplace transform of the transfer function of the inner loop controller of the positive sequence current: The positive-sequence d-axis voltage command value and the positive-sequence q-axis voltage command value can be obtained; among which, Indicates that the Laplace operator is the proportional coefficient corresponding to S2; Indicates the integral coefficient corresponding to the Laplace operator S2; S2 is the Laplace operator in the positive sequence inner loop control process; G(S2) indicates the transfer function corresponding to the Laplace operator S2, which describes how the controller calculates the voltage command value based on the current error (the difference between the command value and the measured value). Proportional coefficient term Determines the immediate response of the inner loop controller to the error, while the integral term is responsible for eliminating the steady-state error. In practical applications, the inner loop controller is usually designed to respond quickly to current changes to reduce tracking errors and improve the dynamic performance of the system. At the same time, the parameters of the inner loop controller ( and ) needs to be carefully adjusted according to the specific system characteristics and requirements to achieve the best control effect. It should be noted that the inner-loop controller of the positive-sequence current works in conjunction with the outer-loop controller to achieve precise control of the positive-sequence current. The outer-loop controller is usually responsible for determining the current command value, while the inner-loop controller is responsible for implementing these command values. In this way, the entire control system can effectively manage the positive-sequence current, thereby maintaining the stable operation of the power system; in addition, in the process of setting the inner-loop controller of the positive-sequence current, the current command value is usually compared with the measured value, and the voltage command value is calculated through the controller algorithm to achieve precise control of the positive-sequence current. Specifically, the setting of the inner-loop controller of the positive-sequence current can be as follows:

[0129] (1) Command value setting: The positive-sequence d-axis current command value and the positive-sequence q-axis current command value are used as the desired positive-sequence current reference values. These values ​​are usually determined according to the system operation requirements and external control instructions.

[0130] (2) Acquisition of measured values: The measured values ​​of the positive-sequence d-axis current and the positive-sequence q-axis current are obtained through current sensors or other measurement methods. These values ​​represent the actual negative-sequence current in the system.

[0131] (3) Inner loop controller output: The positive-sequence d-axis voltage command value and the positive-sequence q-axis voltage command value are the outputs of the inner loop controller. These output values ​​will directly act on the power electronic equipment (such as the inverter) to generate appropriate voltages to drive the current tracking command value.

[0132] Taking the negative sequence inner loop control as an example, during the setting of the inner loop controller of the negative sequence current, (negative sequence d-axis current command value), (negative sequence q-axis current command value) is set to a given value; (measured value of negative sequence d-axis current), (measured value of negative sequence q-axis current), (measured value of negative sequence d-axis voltage) and (measured value of negative sequence q-axis voltage) as input; Laplace transform of the transfer function of the inner loop controller based on the negative sequence current: The positive-sequence d-axis voltage command value and the positive-sequence q-axis voltage command value can be obtained; among which, Indicates that the Laplace operator is the proportional coefficient corresponding to S3; Indicates the integral coefficient corresponding to the Laplace operator S3; S3 is the Laplace operator in the positive sequence inner loop control process; G(S3) indicates the transfer function corresponding to the Laplace operator S3, which describes how the controller calculates the voltage command value based on the current error (the difference between the command value and the measured value); where, and is the proportional coefficient and integral coefficient of the inner loop controller of the negative sequence current; the proportional coefficient term Determines the immediate response of the inner loop controller to the error, while the integral coefficient term is responsible for eliminating the steady-state error. In practical applications, the inner loop controller is usually designed to respond quickly to current changes to reduce tracking errors and improve the dynamic performance of the system. At the same time, the parameters of the inner loop controller ( and ) needs to be carefully adjusted according to the specific system characteristics and requirements to achieve the best control effect. It should be noted that the inner-loop controller of the negative-sequence current works in conjunction with the outer-loop controller to achieve precise control of the negative-sequence current. The outer-loop controller is usually responsible for determining the current command value, while the inner-loop controller is responsible for implementing these command values. In this way, the entire control system can effectively manage the negative-sequence current, thereby maintaining the stable operation of the power system; in the process of setting the inner-loop controller of the negative-sequence current, the current command value is usually compared with the measured value, and the voltage command value is calculated through the controller algorithm to achieve precise control of the negative-sequence current. Specifically, the setting of the inner-loop controller can be as follows:

[0133] (1) Command value setting: The negative-sequence d-axis current command value and the negative-sequence q-axis current command value are used as the desired negative-sequence current reference values. These values ​​are usually determined according to the system operation requirements and external control instructions.

[0134] (2) Acquisition of measured values: The measured values ​​of the negative-sequence d-axis current and the negative-sequence q-axis current are obtained through current sensors or other measurement methods. These values ​​represent the actual negative-sequence current in the system.

[0135] (3) Inner loop controller output: The negative-sequence d-axis voltage command value and the negative-sequence q-axis voltage command value are the outputs of the inner loop controller. These output values ​​will directly act on the power electronic equipment (such as the inverter) to generate appropriate voltages to drive the current tracking command value.

[0136] In this implementation, when the present invention controls the inner loop controller, by comparing the current command value with the measured value and calculating the voltage command value through the controller algorithm, it can not only realize the precise control of the positive sequence current and negative sequence current in the power electronic equipment, but also improve the performance of the power electronic equipment, including improving the dynamic response capability, improving the power quality, reducing the system loss, enhancing the flexibility and reliability of the system, optimizing the resource utilization and supporting the stability of the power grid. These effects work together to improve the performance of power electronic equipment in different application scenarios, ensuring that it can effectively cope with various challenges.

[0137] In view of the problem that during the fault crossing process of existing power electronic equipment, the integral value is kept in a maintained state for a long time, resulting in difficulty in quickly recovering to the pre-fault state after the fault is recovered, the present invention proposes a high-reliability low voltage crossing control method for power electronic equipment. By setting a dual closed-loop control mode for the power electronic equipment, and when the operation mode of the outer loop controller of the power electronic equipment is a grid-forming control, an integral holding control strategy is set for the outer loop controller to help the power electronic equipment maintain stable voltage and frequency output during a period of grid voltage imbalance or drop; by performing current control on the inner loop controller, it is ensured that the output current of the power electronic equipment can quickly and accurately track the current command value given by the outer loop controller, so that the power electronic equipment can not only adapt to various application scenarios, but also facilitate the current command value after the fault is recovered to quickly return to a normal level, thereby realizing rapid information processing and recovery of the power electronic equipment in a fault state, minimizing the impact of the fault, and improving the fault crossing speed and the success rate of fault crossing.

[0138] Embodiment 2:

[0139] The present invention based on the same inventive concept also provides a high reliability power electronic equipment low voltage ride through control system, the structural composition diagram is as follows Figure 6 As shown, including:

[0140] Outer loop control module: used for setting an integral hold control strategy for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment when the operation mode of the outer loop controller of the power electronic equipment is grid-type control, and outputting the positive and negative sequence dq axis current command values ​​after integral hold control;

[0141] Inner loop control module: used to output corresponding voltage command values ​​through the inner loop controller of power electronic equipment based on the positive and negative sequence dq axis current command values ​​after integral hold control;

[0142] Voltage ride-through control module: used to perform low voltage ride-through control on power electronic equipment according to the voltage command value.

[0143] Optionally, the positive and negative sequence dq axis current command values ​​of the power electronic equipment in the outer loop control module are obtained by Laplace transforming the transfer function of the grid-type controller in the outer loop controller.

[0144] For example, the power electronic equipment in the outer loop control module may include one or more of the following: a VSC converter, an energy storage device, a reactive power compensation device, and a doubly-fed wind turbine generator.

[0145] For example, the positive and negative sequence dq axis current command values ​​in the outer loop control module may include: a positive sequence dq axis current command value and a negative sequence dq axis current command value;

[0146] For example, the positive-sequence dq-axis current command value mentioned above includes: a positive-sequence d-axis current command value and a positive-sequence q-axis current command value;

[0147] For example, the above-mentioned 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;

[0148] For example, the voltage command value corresponding to the positive-sequence d-axis current command value is a positive-sequence d-axis voltage command value;

[0149] For example, the voltage command value corresponding to the positive-sequence q-axis current command value is a positive-sequence q-axis voltage command value;

[0150] For example, the voltage command value corresponding to the above-mentioned negative-sequence d-axis current command value is a negative-sequence d-axis voltage command value;

[0151] For example, the voltage command value corresponding to the negative-sequence q-axis current command value is a negative-sequence q-axis voltage command value.

[0152] In a possible implementation, the outer loop control module may be used to:

[0153] Obtain positive and negative sequence dq axis current command values ​​of power electronic equipment;

[0154] The positive and negative sequence dq axis current command values ​​are limited by the hysteresis comparator to obtain the limited positive and negative sequence dq axis current command values;

[0155] When the positive and negative sequence dq axis current command values ​​after limitation do not reach the upper limit of the hysteresis comparator, a saturation exit command is issued;

[0156] When the positive and negative sequence dq axis current command values ​​after limitation reach the upper limit of the hysteresis comparator, a saturation command is issued; and according to the saturation command, an integral hold control strategy is set for the outer loop controller to output the positive and negative sequence dq axis current command values ​​after integral hold control.

[0157] In a possible implementation, the process of setting the integral hold control strategy for the outer loop controller in the above-mentioned loop control module may include:

[0158] According to the positive and negative sequence dq axis current command values ​​after limitation, the integral value of the outer loop controller is obtained;

[0159] The integral value of the outer loop controller is maintained at the current value until a saturation exit instruction is received, and the integral value of the outer loop controller is restored.

[0160] In a possible implementation manner, the outer loop control module may also be used to:

[0161] When the outer loop controller is a negative-sequence outer loop controller and the operation mode of the negative-sequence outer loop controller is grid-following control, the negative-sequence dq-axis current command value of the power electronic equipment is set to a preset value.

[0162] In a possible implementation, the outer loop control module may also be used to:

[0163] When the outer loop controller of the power electronic equipment is a positive sequence outer loop controller, and the operation mode of the positive sequence outer loop controller is grid-following control, the AC voltage dq axis measured value and the power command value of the power electronic equipment are obtained;

[0164] According to the measured value of the AC voltage dq axis and the power command value of the power electronic equipment, the positive sequence dq axis current command value output by the positive sequence outer loop controller under the grid-following control is calculated;

[0165] Based on the positive-sequence dq-axis current command value output by the positive-sequence outer-loop controller under grid-following control, the corresponding voltage command value is output through the inner-loop controller of the power electronic equipment.

[0166] For example, the AC voltage dq axis measured value in the outer loop control module may include: the AC voltage d axis measured value and the AC voltage q axis measured value;

[0167] For example, the above-mentioned power command value may include: an active power command value and a reactive power command value.

[0168] For example, the calculation formula corresponding to the positive-sequence d-axis current command value output by the positive-sequence outer-loop controller in the above outer-loop control module under the grid-following control is as follows:

[0169]

[0170] For example, the calculation formula corresponding to the positive-sequence q-axis current command value output by the above-mentioned positive-sequence outer loop controller under grid-following control is as follows:

[0171]

[0172] in, Indicates the positive sequence d-axis current command value; Indicates the positive sequence q-axis current command value; u d Indicates the measured value of the AC voltage d axis; u q represents the actual measured value of the AC voltage q axis; p represents the active power command value; q′ represents the reactive power command value.

[0173] Embodiment 3:

[0174] like Figure 7As shown, the present invention also provides an electronic device, which may be a computer device, a single-chip device, a smart mobile device, etc. The electronic device 700 in this embodiment includes a processor 701 and a memory 702. The processor 701 is electrically connected to the memory 702.

[0175] The processor 701 is the control center of the electronic device 700. It uses various interfaces and lines to connect various parts of the entire electronic device. It executes various functions of the electronic device and processes data by running or calling computer programs stored in the memory 702, and calling data stored in the memory 702, thereby monitoring the electronic device as a whole.

[0176] In this embodiment, the processor 701 in the electronic device 700 will load the instructions corresponding to the processes of one or more computer programs into the memory 702 according to the following steps, and the processor 701 will run the computer program stored in the memory 702 to achieve various functions, such as: setting the control mode of the power electronic equipment to dual closed-loop control, wherein the dual closed-loop control specifically includes outer loop control and inner loop control; setting the input, output and transfer function of the positive-sequence outer loop controller; setting the input, output and transfer function of the negative-sequence outer loop controller; when the outer loop adopts grid-type control, setting an integral holding control strategy; performing the transfer function and output of the positive-sequence inner loop current controller according to the outer loop input; performing the transfer function and output of the negative-sequence inner loop current controller according to the outer loop input.

[0177] like Figure 8 As shown, in some embodiments, the electronic device 700 may further include: a display 703, a radio frequency circuit 704, an audio circuit 705, a wireless fidelity module 706, and a power supply 707. The display 703, the radio frequency circuit 704, the audio circuit 705, the wireless fidelity module 706, and the power supply 707 are electrically connected to the processor 701, respectively.

[0178] The display 703 may be used to display information input by the user or information provided to the user and various graphical user interfaces, which may be composed of graphics, text, icons, videos, and any combination thereof. The display 703 may include a display panel, and in some embodiments, the display panel may be configured in the form of a liquid crystal display (LCD) or an organic light-emitting diode (OLED).

[0179] The radio frequency circuit 704 can be used to send and receive radio frequency signals to establish wireless communication with network devices or other electronic devices through wireless communication, and to send and receive signals between network devices or other electronic devices.

[0180] The audio circuit 705 may be used to provide an audio interface between a user and the electronic device through a speaker and a microphone.

[0181] The wireless fidelity module 706 can be used for short-range wireless transmission, and can help users to send and receive emails, browse websites, and access streaming media, etc. It provides users with wireless broadband Internet access.

[0182] The power supply 707 can be used to supply power to various components of the electronic device 700. In some embodiments, the power supply 707 can be logically connected to the processor 701 through a power management system, so that the power management system can manage charging, discharging, power consumption and other functions.

[0183] although Figure 8 Not shown, the electronic device 700 may also include a camera, a Bluetooth module, etc., which will not be described in detail here.

[0184] Embodiment 4:

[0185] 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, of course, 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 high-reliability power electronic equipment in the above embodiment.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] 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. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0190] 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 high-reliability low voltage ride-through control method for power electronic equipment, characterized in that: include: When the operation mode of the outer loop controller of the power electronic equipment is grid-type control, an integral holding control strategy is set for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment, and the positive and negative sequence dq axis current command values ​​after integral holding control are output; Based on the positive and negative sequence dq axis current command values ​​after the integral hold control, outputting corresponding voltage command values ​​through the inner loop controller of the power electronic equipment; According to the voltage 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 positive and negative sequence dq axis current command values ​​include: a positive sequence dq axis current command value and a negative sequence dq axis current 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; The voltage command value corresponding to the positive-sequence d-axis current command value is the positive-sequence d-axis voltage command value; The voltage command value corresponding to the positive-sequence q-axis current command value is the positive-sequence q-axis voltage command value; The voltage command value corresponding to the negative-sequence d-axis current command value is a negative-sequence d-axis voltage command value; The voltage command value corresponding to the negative-sequence q-axis current command value is a negative-sequence q-axis voltage command value.

3. The method according to claim 2, characterized in that The method of setting an integral hold control strategy for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment and outputting the positive and negative sequence dq axis current command values ​​after integral hold control includes: Obtaining positive and negative sequence dq axis current command values ​​of the power electronic equipment; The positive and negative sequence dq axis current command values ​​are limited by a hysteresis comparator to obtain the limited positive and negative sequence dq axis current command values; When the positive and negative sequence dq axis current command values ​​after the limitation do not reach the upper limit of the hysteresis comparator, a saturation exit command is issued; When the positive and negative sequence dq axis current command values ​​after limitation reach the upper limit of the hysteresis comparator, a saturation command is issued; and according to the saturation command, an integral hold control strategy is set for the outer loop controller to output the positive and negative sequence dq axis current command values ​​after integral hold control.

4. The method according to claim 3, characterized in that The step of setting an integral holding control strategy for the outer loop controller includes: Obtaining the integral value of the outer loop controller according to the positive and negative sequence dq axis current command values ​​after the limitation; The integral value of the outer loop controller is maintained at the current value until the saturation exit instruction is received, and the integral value of the outer loop controller is restored.

5. The method according to claim 2, characterized in that The method further comprises: When the outer loop controller of the power electronic equipment is a positive sequence outer loop controller, and the operation mode of the positive sequence outer loop controller is grid-following control, obtaining the AC voltage dq axis measured value and the power command value of the power electronic equipment; Calculating the positive-sequence dq-axis current command value output by the positive-sequence outer-loop controller under grid-following control according to the measured value of the AC voltage dq-axis and the power command value of the power electronic equipment; Based on the positive-sequence dq-axis current command value output by the positive-sequence outer-loop controller under grid-following control, the corresponding voltage command value is output through the inner-loop controller of the power electronic equipment.

6. The method according to claim 5, characterized in that The AC voltage dq axis measured value includes: the AC voltage d axis measured value and the AC voltage q axis measured value; The power command value includes: an active power command value and a reactive power command value.

7. The method according to claim 6, characterized in that The calculation formula corresponding to the positive-sequence d-axis current command value output by the positive-sequence outer loop controller under grid-following control is as follows: The calculation formula corresponding to the positive-sequence q-axis current command value output by the positive-sequence outer loop controller under grid-following control is as follows: in, Indicates the positive sequence d-axis current command value; Indicates the positive sequence q-axis current command value; u d Indicates the measured value of the AC voltage d axis; u q represents the actual measured value of the AC voltage q axis; p represents the active power command value; q′ represents the reactive power command value.

8. The method according to claim 2, characterized in that The method further comprises: When the outer loop controller is a negative-sequence outer loop controller, and the operation mode of the negative-sequence outer loop controller is grid-following control, the negative-sequence dq-axis current command value of the power electronic equipment is set to a preset value.

9. The method according to claim 1, characterized in that The power electronic equipment includes one or more of the following: a VSC converter, an energy storage device, a reactive power compensation device and a doubly-fed wind turbine generator.

10. The method according to claim 1, characterized in that The positive and negative sequence dq axis current command values ​​of the power electronic equipment are obtained by Laplace transformation based on the transfer function of the grid-type controller in the outer loop controller.

11. A high-reliability low voltage ride-through control system for power electronic equipment, characterized in that: include: An outer loop control module is used to set an integral hold control strategy for the outer loop controller based on the acquired positive and negative sequence dq axis current command values ​​of the power electronic equipment when the operation mode of the outer loop controller of the power electronic equipment is grid-type control, and output the positive and negative sequence dq axis current command values ​​after integral hold control; Inner loop control module: used for outputting corresponding voltage command values ​​through the inner loop controller of the power electronic equipment based on the positive and negative sequence dq axis current command values ​​after the integral hold control; Voltage ride-through control module: used to perform low voltage ride-through control on the power electronic equipment according to the voltage command value.

12. The system according to claim 11, characterized in that The positive and negative sequence dq axis current command values ​​in the outer loop control module include: a positive sequence dq axis current command value and a negative sequence dq axis current 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; The voltage command value corresponding to the positive-sequence d-axis current command value is the positive-sequence d-axis voltage command value; The voltage command value corresponding to the positive-sequence q-axis current command value is the positive-sequence q-axis voltage command value; The voltage command value corresponding to the negative-sequence d-axis current command value is a negative-sequence d-axis voltage command value; The voltage command value corresponding to the negative-sequence q-axis current command value is a negative-sequence q-axis voltage command value.

13. The system of claim 12, wherein: The outer loop control module is specifically used for: Obtaining positive and negative sequence dq axis current command values ​​of the power electronic equipment; The positive and negative sequence dq axis current command values ​​are limited by a hysteresis comparator to obtain the limited positive and negative sequence dq axis current command values; When the positive and negative sequence dq axis current command values ​​after the limitation do not reach the upper limit of the hysteresis comparator, a saturation exit command is issued; When the positive and negative sequence dq axis current command values ​​after limitation reach the upper limit of the hysteresis comparator, a saturation command is issued; and according to the saturation command, an integral hold control strategy is set for the outer loop controller to output the positive and negative sequence dq axis current command values ​​after integral hold control.

14. 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 high-reliability low voltage ride-through control method for power electronic equipment as claimed in any one of claims 1 to 10 is implemented.

15. A computing device readable storage medium, characterized in that: An execution program is stored thereon, and when the execution program is executed, a high-reliability low voltage ride-through control method for power electronic equipment as described in any one of claims 1 to 10 is implemented.

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