Amplitude limiting control method and device for network construction type converter

Abstract

The invention provides an amplitude limiting control method and device for a network-forming converter, and relates to the technical field of new energy power grid control. The method comprises the following steps: carrying out amplitude limiting on an active power given value of the grid-forming converter according to a first comparison result between an active current value and the maximum current of converter hardware in an active power reference value dynamic adjustment link; obtaining the actual active power of the grid-forming converter, and determining the adjustment parameters of the adaptive rotational inertia and damping coefficient adjustment link according to a second comparison result between the actual active power and the active power reference value; and optimizing the rotation inertia constant and the damping coefficient according to the adjustment parameter and the execution period of the converter controller, and carrying out amplitude limiting control on the network-forming converter according to the optimized rotation inertia constant and the optimized damping coefficient. The device executes the method. According to the amplitude limiting control method and device for the network-building type converter provided by the embodiment of the invention, the operation stability of the network-building type converter can be ensured.

Description

Technical Field

[0001] This invention relates to the field of new energy power grid control technology, specifically to a method and device for limiting control of grid-type converters. Background Technology

[0002] With the transformation of the energy system, the power system exhibits the "dual high" characteristics of a high proportion of renewable energy and a high proportion of power electronic equipment. As the proportion of new energy equipment in the power system increases year by year, the gradual reduction of synchronous generators leads to a decrease in the support capacity of the power system. Grid-type converters have voltage and frequency support characteristics, but when voltage or frequency fluctuations occur in the power system, the operating characteristics of grid-type converters can lead to active power overshoot and oscillation problems, which can cause unit failures and shutdowns in severe cases. One advantage of grid-type converters is that their control parameters are flexible and adjustable, which allows them to improve grid-connected stability under dynamic operating conditions. For grid-type converters, a power synchronization loop is used to simulate the swaying characteristics of synchronous generators. When the system experiences disturbances, the grid-type converter can quickly respond and suppress system disturbances, improving system stability. However, due to limited unit overload capacity and power angle instability issues, grid-type converters are prone to instability and shutdown under transient disturbances, affecting their support capacity under transient conditions.

[0003] The existing technical solution is described as follows:

[0004] 1. By considering the rate of change of frequency, adaptive control of the virtual inertia of the grid-type converter is achieved, thus optimizing the overshoot and oscillation problems in the dynamic process of the system.

[0005] 2. Adaptive control of damping and inertia J optimizes the dynamic process of the grid-type converter, but the control method used is a "bar-to-bar control", which can only switch control parameters between two fixed values.

[0006] 3. An exponential adaptive function was designed to make the adaptive parameters change exponentially, avoiding abrupt changes in the parameters. However, this introduced two additional control coefficients, which increased the difficulty of parameter tuning.

[0007] 4. The optimization effects of different adaptive functions such as arctangent, exponential and "bar-bar" on the dynamic process of grid-type converters are compared, but the limiting effect of steady-state deviation is not considered.

[0008] The shortcomings of the existing technical solutions are explained as follows:

[0009] 1. Disconnect between dynamic optimization and steady-state deviation: Existing research mainly focuses on the optimization of dynamic processes of grid-type converters (such as overshoot and oscillation), while lacking research on the steady-state deviation of grid-type converters under grid frequency disturbances, resulting in insufficient balance between dynamic optimization and steady-state performance.

[0010] 2. Limitations of control methods: Some methods (such as rod-rod control) can only switch between a limited number of control parameters, lacking flexibility; while exponential adaptive functions, although smooth, introduce additional control coefficients, increasing the complexity of parameter tuning.

[0011] 3. Ignoring steady-state deviation: Existing research has not fully considered the limiting effect of steady-state deviation, which may lead to unsatisfactory steady-state performance of the system under grid frequency disturbances. Summary of the Invention

[0012] To address the problems in the prior art, embodiments of the present invention provide a method and apparatus for limiting control of a grid-type converter, which can at least partially solve the problems existing in the prior art.

[0013] On one hand, this invention proposes a limiting control method for a grid-type converter. This limiting control method is based on the optimized power synchronization unit of the grid-type converter. The optimized power synchronization unit includes a dynamic adjustment stage for the active power reference value and an adaptive adjustment stage for rotational inertia and damping coefficient. The limiting control method for the grid-type converter includes:

[0014] The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0015] Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0016] The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

[0017] The step of limiting the active power setpoint of the grid-type converter based on the first comparison result between the maximum current of the converter hardware in the dynamic adjustment link according to the active current value and the active power reference value includes:

[0018] If the active current value is determined to be less than or equal to the maximum current of the converter hardware, then the active power reference value is determined as the active power setpoint.

[0019] The step of limiting the active power setpoint of the grid-type converter based on the first comparison result includes:

[0020] If it is determined that the active current value is greater than the maximum current of the converter hardware, then the active power setpoint is determined based on the adjustment coefficient, the rated current of the converter, the active current value, and the active power reference value.

[0021] The step of determining the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment mechanism based on the second comparison result between the actual active power and the active power reference value includes:

[0022] If it is determined that the absolute value between the actual active power and the active power reference value is greater than the first preset difference, then the adjustment parameter is determined to be the second adjustment parameter used to reduce the moment of inertia and damping coefficient.

[0023] If it is determined that the absolute value between the actual active power and the reference active power value is less than or equal to a first preset difference, and the absolute value between the actual active power and the reference active power value is less than a second preset difference, then the adjustment parameter is determined to be the first adjustment parameter used to increase the moment of inertia and damping coefficient.

[0024] The optimization of the rotational inertia constant and damping coefficient based on the adjustment parameters and the converter controller execution cycle includes:

[0025] The rotational inertia constant and damping coefficient are optimized through iterative calculation based on the following expression:

[0026]

[0027] Wherein, VSG_J1 is the rotational inertia constant during the nth iteration calculation, VSG_D1 is the damping coefficient during the nth iteration calculation, K2 is the second adjustment parameter, K1 is the first adjustment parameter, and Ts is the execution cycle of the converter controller;

[0028] Amplitude-limiting optimization is performed on the rotational inertia constant and damping coefficient after iterative calculation optimization.

[0029] The step of performing amplitude limiting optimization on the iteratively calculated and optimized rotational inertia constant includes:

[0030] For the rotational constant of inertia:

[0031] If it is determined that the rotational inertia constant after iterative calculation and optimization is greater than the upper limit value of the rotational inertia constant, then the upper limit value of the rotational inertia constant is taken as the rotational inertia constant after amplitude limiting optimization.

[0032] If it is determined that the rotational inertia constant after iterative calculation and optimization is less than or equal to the upper limit of the rotational inertia constant and less than the lower limit of the rotational inertia constant, then the lower limit of the rotational inertia constant is taken as the rotational inertia constant after amplitude limiting optimization.

[0033] For the damping coefficient:

[0034] If it is determined that the damping coefficient after iterative calculation and optimization is greater than the upper limit of the damping coefficient, then the upper limit of the damping coefficient is used as the damping coefficient after the amplitude limiting optimization.

[0035] If it is determined that the damping coefficient after iterative calculation and optimization is less than or equal to the upper limit of the damping coefficient and less than the lower limit of the damping coefficient, then the lower limit of the damping coefficient is taken as the damping coefficient after amplitude limiting optimization.

[0036] On one hand, this invention proposes a limiting control device for a grid-type converter. This limiting control device is executed based on the optimized power synchronization unit of the grid-type converter. The optimized power synchronization unit includes a dynamic adjustment link for the active power reference value and an adaptive adjustment link for the moment of inertia and damping coefficient. The limiting control device for the grid-type converter includes:

[0037] The limiting unit is used to obtain the active current value of the grid-type converter and the active power reference value issued by the external controller, and to limit the active power setpoint of the grid-type converter according to the first comparison result between the active current value and the active power reference value and the maximum current of the converter hardware in the dynamic adjustment link.

[0038] The determining unit is used to obtain the actual active power of the grid-type converter and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0039] The optimization unit is used to optimize the rotational inertia constant and damping coefficient according to the adjustment parameters and the converter controller execution cycle, and to perform amplitude limiting control on the grid-type converter according to the optimized rotational inertia constant and optimized damping coefficient.

[0040] In another aspect, embodiments of the present invention provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the following method:

[0041] The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0042] Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0043] The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

[0044] This invention provides a computer-readable storage medium, comprising:

[0045] The computer-readable storage medium stores a computer program that, when executed by a processor, implements the following method:

[0046] The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0047] Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0048] The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

[0049] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the following method:

[0050] The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0051] Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0052] The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

[0053] The method and apparatus for limiting control of a grid-type converter provided in this invention obtains the active current value of the grid-type converter and the active power reference value issued by the external controller. Based on a first comparison result between the active current value and the maximum current of the converter hardware in the dynamic adjustment link of the active power reference value, the active power setpoint of the grid-type converter is limited. The actual active power of the grid-type converter is obtained, and based on a second comparison result between the actual active power and the active power reference value, the adjustment parameters of the adaptive rotational inertia and damping coefficient adjustment link are determined. The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is limited based on the optimized rotational inertia constant and optimized damping coefficient, thus ensuring the stability of the grid-type converter's operation. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0055] Figure 1 This is a flowchart illustrating a grid-type converter limiting control method according to an embodiment of the present invention.

[0056] Figure 2 This is a schematic diagram of the structure of the grid-type converter provided in an embodiment of the present invention.

[0057] Figure 3 This is a control block diagram of the power synchronization unit of a grid-type converter provided in an embodiment of the present invention.

[0058] Figure 4 This is a control block diagram of the optimized power synchronization unit of the grid-type converter provided in this embodiment of the invention.

[0059] Figure 5 This is a flowchart illustrating a grid-type converter limiting control method provided in another embodiment of the present invention.

[0060] Figure 6 This is a schematic diagram illustrating the actual active power effect under a step change in the active power reference value provided in the embodiments of the present invention.

[0061] Figure 7 This is a schematic diagram illustrating the actual active power effect under power grid phase angle jump provided in an embodiment of the present invention.

[0062] Figure 8This is a schematic diagram of the structure of a grid-type converter limiting control device provided in an embodiment of the present invention.

[0063] Figure 9 This is a schematic diagram of the physical structure of a computer device provided in an embodiment of the present invention. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0065] Figure 1 This is a flowchart illustrating a grid-type converter limiting control method according to an embodiment of the present invention, as shown below. Figure 1 As shown, the limiting control method for grid-type converters provided in this embodiment of the invention is executed based on the optimized power synchronization unit of the grid-type converter. The optimized power synchronization unit includes a dynamic adjustment link for the active power reference value and an adaptive adjustment link for the moment of inertia and damping coefficient. The limiting control method for grid-type converters includes:

[0066] Step S1: Obtain the active current value of the grid-type converter and the active power reference value issued by the external controller. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0067] Step S2: Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0068] Step S3: Optimize the rotational inertia constant and damping coefficient according to the adjustment parameters and the converter controller execution cycle, and perform amplitude limiting control on the grid-type converter according to the optimized rotational inertia constant and optimized damping coefficient.

[0069] In step S1 above, the device acquires the active current value of the grid-connected converter and the active power reference value issued by the external controller. Based on a first comparison result between the active current value and the active power reference value, the device limits the active power setpoint of the grid-connected converter's hardware in the dynamic adjustment loop. The device can be a computer device executing this method. The acquisition, storage, use, and processing of data in this application's technical solution all comply with relevant regulations. Figure 2 As shown, the control strategy for grid-type converters is explained below:

[0070] The control strategy for grid-type converters includes a power synchronization unit, a reactive power / voltage control unit, and a modulation signal control loop. Among these, V... grid Z is the grid-side voltage. grid V is the line impedance. pcc C is the grid connection point voltage, and C is the DC-side capacitor. The power synchronization unit uses a virtual synchronization control strategy to generate the internal potential phase of the grid, and the reactive power / voltage control unit generates the internal potential amplitude of the grid. By calculating the internal potential amplitude and phase of the grid-connected converter, the modulation signal required by the modulation signal control link is obtained, and the modulation signal is input to the modulation signal control link, which then generates the drive signal for the converter power devices.

[0071] A power synchronization unit can be represented by the following formula:

[0072]

[0073] Among them, P ref P is the active power setpoint received by the grid-type converter. e ω represents the active power output of the grid-connected converter. * ω is the internal potential angular frequency of the grid-type converter. N The rated angular frequency is 314 rad / s, D is the damping coefficient, and T is the rated angular frequency. J is the inertial time constant.

[0074] As shown in the above formula, the difference between the active power setpoint received by the grid-type converter and the active power output of the grid-type converter is used to generate the internal potential angle θ of the grid-type converter through the modulation signal control loop. The control block diagram of the power synchronization unit of the grid-type converter is as follows. Figure 3 As shown.

[0075] From the power synchronization unit formula and Figure 3 It is known that the swing equation of the power synchronization unit is similar to that of the synchronous generator, and it exhibits second-order system characteristics. When the system is underdamped, when there is a step increase in the active power command, the unit will experience active power oscillation and over-generation problems. When the power over-generation is too excessive, there will be a risk of shutdown.

[0076] To improve the synchronization stability of grid-type converters under active power fluctuations, this invention mainly focuses on the design of an active power reduction reference strategy based on active current, adaptive moment of inertia, and damping coefficient. The specific control block diagram is shown below. Figure 4 As shown, the box connected to the "external controller" corresponds to the "dynamic adjustment of active power reference value", and the box corresponding to the "adaptive strategy" corresponds to the "adaptive adjustment of rotational inertia and damping coefficient".

[0077] The step of limiting the active power setpoint of the grid-type converter based on the first comparison result between the maximum current of the converter hardware in the dynamic adjustment link of the active current value and the active power reference value includes:

[0078] If the active current value is determined to be less than or equal to the maximum current of the converter hardware, then the active power reference value is determined as the active power setpoint.

[0079] The step of limiting the active power setpoint of the grid-type converter based on the first comparison result includes:

[0080] If the active current value is determined to be greater than the maximum current of the converter hardware, then the active power setpoint is determined based on the adjustment coefficient, the converter rated current, the active current value, and the active power reference value. This can be expressed by the following expression:

[0081]

[0082] Among them, P ref P is the given value for active power. set I is the active power reference value. d The active current value can be further defined as the active current value after passing through a low-pass filter, I. N I is the rated current of the converter. max The maximum current of the converter hardware is denoted by k, and the adjustment coefficient is denoted by k.

[0083] As can be seen from the above formula, this method can quickly reduce the active power setpoint when the active power of the grid-type converter is excessively over-generated, and has little impact on the slow dynamic characteristics of the grid.

[0084] In step S2 above, the device acquires the actual active power of the grid-type converter, and determines the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment stage based on a second comparison result between the actual active power and the active power reference value. Determining the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment stage based on the second comparison result between the actual active power and the active power reference value includes:

[0085] If it is determined that the absolute value between the actual active power and the active power reference value is greater than the first preset difference, then the adjustment parameter is determined to be the second adjustment parameter used to reduce the moment of inertia and damping coefficient.

[0086] If it is determined that the absolute value between the actual active power and the reference active power value is less than or equal to a first preset difference, and the absolute value between the actual active power and the reference active power value is less than a second preset difference, then the adjustment parameter is determined to be the first adjustment parameter used to increase the moment of inertia and damping coefficient. Figure 5 As shown, the first preset difference is ΔP1, and the second preset difference is ΔP2.

[0087] In step S3 above, the device optimizes the rotational inertia constant and damping coefficient based on the adjustment parameters and the converter controller execution cycle, and performs amplitude limiting control on the grid-type converter based on the optimized rotational inertia constant and optimized damping coefficient. The optimization of the rotational inertia constant and damping coefficient based on the adjustment parameters and the converter controller execution cycle includes:

[0088] The rotational inertia constant and damping coefficient are optimized through iterative calculation based on the following expression:

[0089]

[0090] Where VSG_J1 is the rotational inertia constant in the nth iteration calculation, VSG_D1 is the damping coefficient in the nth iteration calculation, K2 is the second adjustment parameter, K1 is the first adjustment parameter, and Ts is the execution cycle of the converter controller. When the power system experiences large voltage or frequency disturbances, the slow dynamic characteristics of the grid will cause the generating units to experience faster active power fluctuations. Therefore, an adaptive rotational inertia and damping coefficient method is used to ensure rapid response to system changes during extreme operating conditions and reduce active power fluctuations during system disturbances. The specific implementation block diagram is as follows: Figure 5 As shown.

[0091] Since both excessively large and excessively small rotational inertia constants and damping coefficients can worsen system stability, and excessively large rotational inertia constants and damping coefficients have a greater adverse effect on stability than excessively small rotational inertia constants and damping coefficients, it is first determined whether the absolute value between the actual active power and the active power reference value is greater than the first preset difference, and then it is determined whether the absolute value between the actual active power and the active power reference value is less than the second preset difference.

[0092] The rotational inertia constant and damping coefficient, optimized through iterative calculations, are then subjected to amplitude-limiting optimization. This amplitude-limiting optimization of the rotational inertia constant and damping coefficient after iterative calculations includes:

[0093] For the rotational constant of inertia:

[0094] If it is determined that the rotational inertia constant after iterative calculation and optimization is greater than the upper limit value of the rotational inertia constant, then the upper limit value of the rotational inertia constant is taken as the rotational inertia constant after amplitude limiting optimization.

[0095] If it is determined that the rotational inertia constant after iterative calculation and optimization is less than or equal to the upper limit of the rotational inertia constant and less than the lower limit of the rotational inertia constant, then the lower limit of the rotational inertia constant is taken as the rotational inertia constant after amplitude limiting optimization.

[0096] For the damping coefficient:

[0097] If it is determined that the damping coefficient after iterative calculation and optimization is greater than the upper limit of the damping coefficient, then the upper limit of the damping coefficient is used as the damping coefficient after the amplitude limiting optimization.

[0098] If it is determined that the damping coefficient after iterative calculation and optimization is less than or equal to the upper limit of the damping coefficient and less than the lower limit of the damping coefficient, then the lower limit of the damping coefficient is taken as the damping coefficient after amplitude limiting optimization.

[0099] Similarly, since both excessively large and excessively small rotational inertia constants and damping coefficients will worsen system stability, an excessively large rotational inertia constant and damping coefficient have a greater adverse impact on stability than an excessively small one. Therefore, it is first determined whether the optimized rotational inertia constant after iterative calculation is greater than its upper limit, and then whether it is less than its lower limit. Likewise, it is first determined whether the optimized damping coefficient after iterative calculation is greater than its upper limit, and then whether it is less than its lower limit.

[0100] Limiting control of a grid-type converter based on optimized rotational inertia constant and optimized damping coefficient can include, for example, using... Figure 4 The control block diagram shown applies limiting control to the grid-type converter, where T... J D and D correspond to the optimized rotational inertia constant and optimized damping coefficient, respectively.

[0101] Furthermore, after the step of limiting the amplitude control of the grid-type converter based on the optimized rotational inertia constant and the optimized damping coefficient, simulation verification of the system phase angle change can be performed, as detailed below:

[0102] like Figure 6 As shown, the horizontal axis represents time, and the vertical axis represents the per-unit value of active power. For a basic strategy as follows... Figure 3 The original control strategies are shown below; Strategy 1 is a control strategy based solely on the dynamic adjustment method of the active power reference value based on the active current; Strategy 2 is a control strategy based on the dynamic adjustment method of the active power reference value based on the active current, and a control strategy combining the adaptive moment of inertia and damping coefficient method.

[0103] like Figure 6As shown, when the grid-type converter performs an active power step response from 0Pu to 1Pu in 7s, compared with the basic strategy, the active power regulation time under strategy 2 is shorter, and the maximum overshoot active power is reduced from 1.28Pu to 1.16Pu.

[0104] like Figure 6 As shown, when the grid-type converter performs an active power step response from 0Pu to 1Pu in 7s, compared with the basic strategy, the active power regulation time under strategy 2 is shorter, and the maximum overshoot active power is reduced from 1.28Pu to 1.16Pu.

[0105] like Figure 7 As shown, when the grid-type converter is subjected to phase angle jump disturbance test at 15s, compared with the basic strategy, the maximum active power fluctuation value under strategy 2 is reduced from 1.23Pu to 1.12Pu, and the active power fluctuation time is shorter.

[0106] Based on simulation verification results, it can be seen that the method of the present invention can improve the active power control stability of the grid converter under system disturbances.

[0107] The limiting control method for grid-type converters provided in this invention addresses the issues of limited overload capacity and power angle instability in grid-type converters, which are prone to instability and shutdown under transient disturbances. This invention employs a two-stage control approach to ensure the transient stability of the grid-type converter. It utilizes a dynamic adjustment method based on active current reference active power to reduce the risk of power angle instability and device failure under active power overload. Furthermore, it employs an adaptive method based on active power deviation control using rotational inertia and damping coefficients to improve the rapid tracking of active power under extreme operating conditions, thus ensuring the operational stability of the grid-type converter.

[0108] The limiting control method for grid-type converters provided in this invention obtains the active current value of the grid-type converter and the active power reference value issued by the external controller. Based on a first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited. The actual active power of the grid-type converter is obtained, and based on a second comparison result between the actual active power and the active power reference value, the adjustment parameters of the adaptive rotational inertia and damping coefficient adjustment loop are determined. The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle. Limiting control of the grid-type converter is then performed based on the optimized rotational inertia constant and optimized damping coefficient, ensuring the stability of the grid-type converter's operation.

[0109] Further, the step of limiting the active power setpoint of the grid-type converter based on the first comparison result between the maximum current of the converter hardware in the dynamic adjustment link according to the active current value and the active power reference value includes:

[0110] If the active current value is determined to be less than or equal to the maximum current of the converter hardware, then the active power reference value is determined as the active power setpoint. This can be referred to the above embodiment for further explanation, and will not be repeated here.

[0111] Further, the step of limiting the active power setpoint of the grid-type converter based on the first comparison result includes:

[0112] If the active current value is determined to be greater than the maximum current of the converter hardware, then the active power setpoint is determined based on the adjustment coefficient, the rated current of the converter, the active current value, and the active power reference value. This can be referred to the above embodiment for further explanation, and will not be repeated here.

[0113] Further, determining the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment mechanism based on the second comparison result between the actual active power and the active power reference value includes:

[0114] If it is determined that the absolute value between the actual active power and the active power reference value is greater than the first preset difference, then the adjustment parameter is determined to be the second adjustment parameter used to reduce the moment of inertia and damping coefficient; this can be referred to the above embodiment for explanation, and will not be repeated here.

[0115] If it is determined that the absolute value between the actual active power and the reference active power value is less than or equal to a first preset difference, and the absolute value between the actual active power and the reference active power value is less than a second preset difference, then the adjustment parameter is determined to be the first adjustment parameter used to increase the moment of inertia and damping coefficient. This can be referred to the above embodiments for explanation, and will not be repeated here.

[0116] Furthermore, the optimization of the rotational inertia constant and damping coefficient based on the adjustment parameters and the converter controller execution cycle includes:

[0117] The rotational inertia constant and damping coefficient are optimized through iterative calculation based on the following expression:

[0118]

[0119] Wherein, VSG_J1 is the rotational inertia constant during the nth iteration calculation, VSG_D1 is the damping coefficient during the nth iteration calculation, K2 is the second adjustment parameter, K1 is the first adjustment parameter, and Ts is the execution cycle of the converter controller; the above embodiments can be referred to for explanation, and will not be repeated here.

[0120] The rotational inertia constant and damping coefficient, after iterative calculation and optimization, are then subjected to amplitude-limiting optimization. This can be referred to the above embodiments for further explanation and will not be repeated here.

[0121] Furthermore, the step of performing amplitude limiting optimization on the iteratively calculated and optimized rotational inertia constant includes:

[0122] For the rotational constant of inertia:

[0123] If it is determined that the rotational inertia constant after iterative calculation and optimization is greater than the upper limit value of the rotational inertia constant, then the upper limit value of the rotational inertia constant is used as the rotational inertia constant after amplitude limiting optimization; this can be referred to the above embodiment for explanation, and will not be repeated here.

[0124] If it is determined that the rotational inertia constant after iterative calculation and optimization is less than or equal to the upper limit of the rotational inertia constant and less than the lower limit of the rotational inertia constant, then the lower limit of the rotational inertia constant is taken as the rotational inertia constant after amplitude limiting optimization; this can be referred to the above embodiments for explanation, and will not be repeated here.

[0125] For the damping coefficient:

[0126] If it is determined that the damping coefficient after iterative calculation and optimization is greater than the upper limit of the damping coefficient, then the upper limit of the damping coefficient is used as the damping coefficient after the amplitude limiting optimization; this can be referred to the above embodiment for explanation, and will not be repeated here.

[0127] If the damping coefficient after iterative calculation and optimization is determined to be less than or equal to the upper limit of the damping coefficient and less than the lower limit of the damping coefficient, then the lower limit of the damping coefficient is taken as the damping coefficient after amplitude limiting optimization. Refer to the above embodiments for further details.

[0128] Figure 8 This is a schematic diagram of the structure of a grid-type converter limiting control device provided in an embodiment of the present invention, as shown below. Figure 8 As shown, the grid-type converter limiting control device provided in this embodiment of the invention is executed based on the optimized power synchronization unit of the grid-type converter. The optimized power synchronization unit includes a dynamic adjustment link for the active power reference value and an adaptive adjustment link for the moment of inertia and damping coefficient. The grid-type converter limiting control device includes a limiting unit 801, a determining unit 802, and an optimizing unit 803, wherein:

[0129] The limiting unit 801 is used to acquire the active current value of the grid-type converter and the active power reference value issued by the external controller, and to limit the active power setpoint of the grid-type converter according to the first comparison result between the active current value and the active power reference value and the maximum current of the converter hardware in the dynamic adjustment link. The determining unit 802 is used to acquire the actual active power of the grid-type converter, and to determine the adjustment parameters of the adaptive rotational inertia and damping coefficient adjustment link according to the second comparison result between the actual active power and the active power reference value. The optimization unit 803 is used to optimize the rotational inertia constant and damping coefficient according to the adjustment parameters and the converter controller execution cycle, and to perform limiting control on the grid-type converter according to the optimized rotational inertia constant and optimized damping coefficient.

[0130] Specifically, the limiting unit 801 in the device is used to acquire the active current value of the grid-type converter and the active power reference value issued by the external controller, and limits the active power setpoint of the grid-type converter according to the first comparison result between the active current value and the active power reference value and the maximum current of the converter hardware in the dynamic adjustment link; the determining unit 802 is used to acquire the actual active power of the grid-type converter, and determines the adjustment parameters of the adaptive rotational inertia and damping coefficient adjustment link according to the second comparison result between the actual active power and the active power reference value; the optimization unit 803 is used to optimize the rotational inertia constant and damping coefficient according to the adjustment parameters and the converter controller execution cycle, and performs limiting control on the grid-type converter according to the optimized rotational inertia constant and optimized damping coefficient.

[0131] The grid-type converter limiting control device provided in this embodiment of the invention acquires the active current value of the grid-type converter and the active power reference value issued by the external controller. Based on a first comparison result between the active current value and the active power reference value, the device limits the active power setpoint of the grid-type converter in a dynamic adjustment loop. It then acquires the actual active power of the grid-type converter and determines the adjustment parameters of the adaptive rotational inertia and damping coefficient adjustment loop based on a second comparison result between the actual active power and the active power reference value. Finally, it optimizes the rotational inertia constant and damping coefficient based on the adjustment parameters and the converter controller execution cycle, and performs limiting control on the grid-type converter based on the optimized rotational inertia constant and damping coefficient, thereby ensuring the stability of the grid-type converter's operation.

[0132] The embodiments of the present invention provide a grid-type converter limiting control device that can be used to execute the processing flow of the above-described method embodiments. Its functions will not be repeated here, but can be referred to the detailed description of the above-described method embodiments.

[0133] Figure 9This is a schematic diagram of the physical structure of a computer device provided in an embodiment of the present invention, such as... Figure 9 As shown, the computer device includes: a memory 901, a processor 902, and a computer program stored in the memory 901 and executable on the processor 902. When the processor 902 executes the computer program, it implements the following method:

[0134] The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0135] Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0136] The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

[0137] This embodiment discloses a computer program product, which includes a computer program that, when executed by a processor, implements the following method:

[0138] The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0139] Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0140] The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

[0141] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the following method:

[0142] The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited.

[0143] Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value.

[0144] The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

[0145] Compared with existing technologies, the limiting control method for grid-type converters provided in this invention obtains the active current value of the grid-type converter and the active power reference value issued by the external controller. Based on a first comparison result between the active current value and the maximum current of the converter hardware in the dynamic adjustment loop, the active power setpoint of the grid-type converter is limited. The actual active power of the grid-type converter is obtained, and based on a second comparison result between the actual active power and the active power reference value, the adjustment parameters of the adaptive rotational inertia and damping coefficient adjustment loop are determined. The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle. Limiting control of the grid-type converter is then performed based on the optimized rotational inertia constant and optimized damping coefficient, ensuring the stability of the grid-type converter's operation.

[0146] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied 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.

[0147] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0148] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0149] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0150] In the description of this specification, the references to terms such as "an embodiment," "a specific embodiment," "some embodiments," "for example," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0151] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A limiting control method for a grid-type converter, characterized in that, The aforementioned limiting control method for grid-type converters is based on the optimized power synchronization unit of the grid-type converter. The optimized power synchronization unit includes a dynamic adjustment stage for the active power reference value and an adaptive adjustment stage for rotational inertia and damping coefficient. The limiting control method for grid-type converters includes: The active current value of the grid-type converter and the active power reference value issued by the external controller are obtained. Based on the first comparison result between the active current value and the active power reference value, the active power setpoint of the grid-type converter is limited. Obtain the actual active power of the grid-type converter, and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value. The rotational inertia constant and damping coefficient are optimized based on the adjustment parameters and the converter controller execution cycle, and the grid-type converter is subjected to amplitude limiting control based on the optimized rotational inertia constant and optimized damping coefficient.

2. The limiting control method for a grid-type converter according to claim 1, characterized in that, The step of limiting the active power setpoint of the grid-type converter based on the first comparison result between the maximum current of the converter hardware in the dynamic adjustment link of the active current value and the active power reference value includes: If the active current value is determined to be less than or equal to the maximum current of the converter hardware, then the active power reference value is determined as the active power setpoint.

3. The limiting control method for a grid-type converter according to claim 1, characterized in that, The step of limiting the active power setpoint of the grid-type converter based on the first comparison result includes: If it is determined that the active current value is greater than the maximum current of the converter hardware, then the active power setpoint is determined based on the adjustment coefficient, the rated current of the converter, the active current value, and the active power reference value.

4. The limiting control method for a grid-type converter according to claim 1, characterized in that, The step of determining the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment loop based on the second comparison result between the actual active power and the active power reference value includes: If it is determined that the absolute value between the actual active power and the active power reference value is greater than the first preset difference, then the adjustment parameter is determined to be the second adjustment parameter used to reduce the moment of inertia and damping coefficient. If it is determined that the absolute value between the actual active power and the reference active power value is less than or equal to a first preset difference, and the absolute value between the actual active power and the reference active power value is less than a second preset difference, then the adjustment parameter is determined to be the first adjustment parameter used to increase the moment of inertia and damping coefficient.

5. The limiting control method for a grid-type converter according to claim 4, characterized in that, The optimization of the rotational inertia constant and damping coefficient based on the adjustment parameters and the converter controller execution cycle includes: The rotational inertia constant and damping coefficient are optimized through iterative calculation based on the following expression: Wherein, VSG_J1 is the rotational inertia constant during the nth iteration calculation, VSG_D1 is the damping coefficient during the nth iteration calculation, K2 is the second adjustment parameter, K1 is the first adjustment parameter, and Ts is the execution cycle of the converter controller; Amplitude-limiting optimization is performed on the rotational inertia constant and damping coefficient after iterative calculation optimization.

6. The limiting control method for a grid-type converter according to claim 5, characterized in that, The step of performing amplitude limiting optimization on the iteratively calculated and optimized rotational inertia constant includes: For the rotational constant of inertia: If it is determined that the rotational inertia constant after iterative calculation and optimization is greater than the upper limit value of the rotational inertia constant, then the upper limit value of the rotational inertia constant is taken as the rotational inertia constant after amplitude limiting optimization. If it is determined that the rotational inertia constant after iterative calculation and optimization is less than or equal to the upper limit of the rotational inertia constant and less than the lower limit of the rotational inertia constant, then the lower limit of the rotational inertia constant is taken as the rotational inertia constant after amplitude limiting optimization. For the damping coefficient: If it is determined that the damping coefficient after iterative calculation and optimization is greater than the upper limit of the damping coefficient, then the upper limit of the damping coefficient is used as the damping coefficient after the amplitude limiting optimization. If it is determined that the damping coefficient after iterative calculation and optimization is less than or equal to the upper limit of the damping coefficient and less than the lower limit of the damping coefficient, then the lower limit of the damping coefficient is taken as the damping coefficient after amplitude limiting optimization.

7. A limiting control device for a grid-type converter, characterized in that, The limiting control device for the grid-type converter is executed based on the optimized power synchronization unit of the grid-type converter. The optimized power synchronization unit includes a dynamic adjustment link for the active power reference value and an adaptive adjustment link for the moment of inertia and damping coefficient. The limiting control device for the grid-type converter includes: The limiting unit is used to obtain the active current value of the grid-type converter and the active power reference value issued by the external controller, and to limit the active power setpoint of the grid-type converter according to the first comparison result between the active current value and the active power reference value and the maximum current of the converter hardware in the dynamic adjustment link. The determining unit is used to obtain the actual active power of the grid-type converter and determine the adjustment parameters of the adaptive moment of inertia and damping coefficient adjustment link based on the second comparison result between the actual active power and the active power reference value. The optimization unit is used to optimize the rotational inertia constant and damping coefficient according to the adjustment parameters and the converter controller execution cycle, and to perform amplitude limiting control on the grid-type converter according to the optimized rotational inertia constant and optimized damping coefficient.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method of any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method of any one of claims 1 to 6.

10. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the method of any one of claims 1 to 6.

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