摘要
并网逆变器输出阻抗是判定其并网运行稳定性的重要参数,通常采用谐波电流注入法测量。但由于并网逆变器本身存在背景谐波,会影响测量结果的准确性,采用非整数谐波的偏频电流注入方法能够有效避免该问题。然而,由于实际电网运行频率在一定范围内波动,采用谐波电流源注入非整数次谐波电流时存在难以同步的问题,从而造成测量误差。针对以上问题,该文利用电压扰动与电流扰动两种阻抗测量方法的等效性,提出通过同一台电压扰动源产生基频及非整数次谐波电压进行逆变器阻抗测量的方法,以提高阻抗测量的准确性,最后通过插值获取逆变器全频段阻抗。实时数字仿真结果证明了所提测量方法的有效性和可行性。
The output impedance of a grid-connected inverter is an important parameter to determine the stability of its operation in the grid. It is usually measured by the harmonic current injection method. However, the background harmonics of the inverter may affect the accuracy of measurement results. The non-integer harmonics current injection method can effectively avoid this problem. Since the actual grid operating frequency fluctuates within a certain range, it is difficult to synchronize when using a harmonic current source to inject a non-integer harmonic current, and the method may cause measurement errors. Aiming at the above problems, this paper uses the equivalence of voltage disturbance and current disturbance, and proposes a method to measure the impedance of inverters by a voltage disturbance source. The voltage disturbance source can generate the fundamental frequency and non-integer harmonic voltage to measure the impedance of the inverter, and hence the accuracy of the impedance measurement is improved. The full-band impedance of the inverter is obtained by interpolation. The proposed measurement method is verified by the real-time digital simulation.
作者
钟佩军
孙建军
司学振
曹志煌
潘静
Zhong Peijun;Sun Jianjun;Si Xuezhen;Cao Zhihuang;Pan Jing(School of Electrical Engineering and Automation Wuhan University,Wuhan 430072 China;State Grid Electric Power Research Institute of Henan Electric Power Company,Zhengzhou 450000 China;State Grid Anhui Electric Power Co.Ltd,Hefei 230061 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2019年第22期4739-4750,共12页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(51777145)
国家电网公司总部科技项目“配电网电能质量干扰源接纳能力评估及有源型治理设备入网检测关键技术研究”资助
关键词
并网逆变器
阻抗建模
电压扰动
偏频
阻抗测量
Grid-connected inverter
impedance modeling
harmonic voltage injection
frequency shift
impedance measurement