非线性负载下的多变流器谐波电压补偿控制策略

多变流器在接入非线性负载的情况下会引起电压畸变。为解决此问题,提出一种谐波电压补偿的综合控制策略。首先,采用虚拟同步发电机控制策略模拟同步发电机的外特性,使逆变器具有惯性和阻尼特性。其次,通过级联广义积分器构建谐波分离网络来提取相应的基波和谐波电流分量。紧接着结合虚拟阻抗构建基波处的感性虚拟阻抗去改善功率均分,以谐波处的阻容性可变虚拟阻抗去改变系统的输出阻抗来补偿相应的谐波电压。然后,在虚拟同步发电机的基础上采用多谐振电压控制器对输出电压的谐波进行抑制。最后,对所提的综合控制策略进行仿真研究,结果验证了所提策略在谐波电压补偿方面的正确性。

Multi-converter harmonic voltage compensation control strategy under nonlinear loads

A multi-converter will cause voltage distortion when it is connected to nonlinear load. In order to solve this problem, a comprehensive control strategy of harmonic voltage compensation is proposed. First, a virtual synchronous generator control strategy is used to simulate the external characteristics of the synchronous generator, which makes the inverter have inertial and damping characteristics. Secondly, the cascaded generalized integrator is used to build harmonic separate network to extract the corresponding fundamental and harmonic current components. And then the inductive virtual impedance used at fundamental wave is combined to improve the average power, and the resistive and capacitive variable virtual impedance used at harmonics wave is employed to change the output impedance of the system to compensate for the harmonic voltage. Then, multi-resonant voltage controller is used to suppress the harmonics of the output voltage based on a virtual synchronous generator. Finally, the simulation of the proposed comprehensive control strategy is carried out. The results verify the correctness of the proposed strategy in harmonic voltage compensation under multi-converter. This work is supported by National Natural Science Foundation of China (No. 61364027).