阅读说明：本技术 并网变流设备的谐振频率辨识方法、装置、设备及介质 (Method, device, equipment and medium for identifying resonant frequency of grid-connected converter equipment ) 是由 吴轩钦 董瑞勇 王国建 周志达 沈文 王二峰 于 2020-06-01 设计创作，主要内容包括：本申请公开了一种并网变流设备的谐振频率辨识方法、装置、电子设备及计算机可读存储介质,该方法包括：获取LCL滤波器的电容电压信号；提取电容电压信号的波动分量信号；将波动分量信号分别送入结构相同、中心频率不同的两个预设辨识控制器以获取输出的两个辨识变量值；基于两个辨识变量值的差值进行PI控制,以实时调整两个预设辨识控制器的中心频率,直至进入闭环稳态；确定两个预设辨识控制器在闭环稳态时的中心频率的平均值,作为并网变流设备的谐振频率。本申请利用中心频率不同的两个预设辨识控制器的辨识结果关于谐振频率的频率特性,结合PI闭环控制可有效追踪辨识并网变流设备的谐振频率,有效提高了辨识速率、精确度和实时性。(The application discloses a method and a device for identifying resonant frequency of grid-connected converter equipment, electronic equipment and a computer readable storage medium, wherein the method comprises the following steps: acquiring a capacitance voltage signal of the LCL filter; extracting a fluctuation component signal of the capacitance voltage signal; respectively sending the fluctuation component signals to two preset identification controllers with the same structure and different center frequencies to obtain two output identification variable values; performing PI control based on the difference value of the two identification variable values to adjust the center frequencies of the two preset identification controllers in real time until the closed loop stable state is reached; and determining the average value of the central frequencies of the two preset identification controllers in the closed loop steady state as the resonant frequency of the grid-connected converter equipment. The frequency characteristic of the identification result of two preset identification controllers with different center frequencies about the resonant frequency is utilized, the resonant frequency of the grid-connected converter equipment can be effectively tracked and identified by combining PI closed-loop control, and the identification rate, the accuracy and the real-time performance are effectively improved.)

1. A method for identifying resonant frequency of grid-connected converter equipment is characterized in that the grid-connected converter equipment comprises an LCL filter, and the method comprises the following steps:

acquiring a capacitance voltage signal of the LCL filter;

extracting a fluctuation component signal of the capacitance voltage signal;

respectively sending the fluctuation component signals to two preset identification controllers with the same structure and different center frequencies to obtain two output identification variable values;

performing PI control based on the difference value of the two identification variable values to adjust the center frequencies of the two preset identification controllers in real time until the closed loop stable state is achieved;

and determining the average value of the central frequencies of the two preset identification controllers in the closed loop steady state as the resonant frequency of the grid-connected converter equipment.

2. The method for identifying resonant frequency according to claim 1, wherein said extracting a fluctuation component signal of the capacitance voltage signal comprises:

extracting a fundamental wave signal of the capacitance voltage signal;

and taking the difference value of the capacitance voltage signal and the fundamental wave signal as the fluctuation component signal.

3. The method according to claim 2, wherein the extracting a fundamental wave signal of the capacitance voltage signal comprises:

extracting the fundamental wave signal according to a preset fundamental wave signal extraction formula, wherein the preset fundamental wave signal extraction formula is as follows:

wherein u is_{c_fund}Is the fundamental wave signal; u. of_cIs the capacitance voltage signal; k is a radical of_fundIs an extraction coefficient; omega_fundIs the fundamental angular frequency.

4. The method according to any one of claims 1 to 3, wherein the output expression of the first one of the two predetermined identification controllers is:

wherein x is_iden1A first identification variable value output by the first preset identification controller; u. of_{c_fluc}Is the fluctuating component signal; omega_c1A preset bandwidth for the first preset identification controller; omega_f1Identifying the center frequency of the first preset identification controller; omega_f0Is the center frequency median; Δ ω_fIs a preset frequency increment value;

the output expression of the second preset identification controller is as follows:

wherein x is_iden2A second identification variable value output by the second preset identification controller; omega_c2The preset bandwidth of the second preset identification controller; omega_f2The center frequency of the second preset identification controller.

5. The method for identifying resonant frequency according to claim 4, wherein the PI controlling based on the difference between the two identification variable values to adjust the center frequencies of the two preset identification controllers in real time until a closed loop steady state is entered comprises:

calculating PI control quantity based on the difference value of the two identification variable values according to a preset PI control formula; the preset PI control formula is as follows:

wherein, Δ ω_PIThe PI control quantity is the PI control quantity; k_PIs a preset proportionality coefficient; k_IIs a preset integral coefficient; e.g. of the type_PIIs the difference between the two identifying variable values;

updating the center frequency intermediate value based on the PI control quantity according to a preset frequency adjustment formula so as to update the center frequencies of the two preset identification controllers based on the center frequency intermediate value; the preset frequency adjustment formula is as follows:

wherein the content of the first and second substances,ω_{res_mid}presetting a reference value for the resonant frequency;L₁the inductance value of the grid-connected converter equipment side of the LCL filter is obtained; l is₂A grid side inductance value for the LCL filter; c_fIs the capacitance value of the LCL filter; l is_gIs the grid inductance.

6. The method for identifying the resonant frequency of claim 5, wherein the determining an average value of the center frequencies of the two preset identification controllers in the closed-loop steady state as the resonant frequency of the grid-connected converter device includes:

and approximately calculating the average value as the resonant frequency of the grid-connected converter equipment according to a preset calculation formula, wherein the preset calculation formula is as follows:

wherein, ω is_resIs the resonance frequency.

7. The resonant frequency identification device of the grid-connected converter equipment is characterized in that the grid-connected converter equipment comprises an LCL filter, and the device comprises:

the acquisition unit is used for acquiring a capacitance voltage signal of the LCL filter;

an extraction unit for extracting a fluctuation component signal of the capacitance voltage signal;

the identification unit is used for respectively sending the fluctuation component signals to two preset identification controllers with the same structure and different center frequencies so as to obtain two output identification variable values;

the adjusting unit is used for carrying out PI control on the basis of the difference value of the two identification variable values so as to adjust the central frequencies of the two preset identification controllers in real time until the closed loop stable state is achieved;

and the determining unit is used for determining the average value of the central frequencies of the two preset identification controllers in the closed loop steady state as the resonant frequency of the grid-connected converter equipment.

8. The apparatus for identifying a resonant frequency of claim 7, wherein the extracting unit is specifically configured to:

extracting a fundamental wave signal of the capacitance voltage signal; and taking the difference value of the capacitance voltage signal and the fundamental wave signal as the fluctuation component signal.

9. An electronic device, comprising:

a memory for storing a computer program;

a processor for executing the computer program to implement the steps of the method for identifying a resonant frequency of a grid-connected inverter device as claimed in any one of claims 1 to 6.

10. A computer-readable storage medium, in which a computer program is stored, which, when being executed by a processor, is configured to implement the steps of the method for identifying a resonant frequency of a grid-connected converter device according to any one of claims 1 to 6.