光储逆变器自适应分数阶重复控制

Adaptive Fractional Order Repetitive Control of Photovoltaic Energy Storage Inverters

HERIC逆变器由于其低漏电流和高效率的特点,在单相光储系统中得到普遍应用,但在非单位功率因数调制下考虑多台光储逆变器并联时,采用下垂控制引起的频率波动会导致逆变器输出电压谐波分量增多、波形畸变等问题。针对该问题,此处提出了基于二阶广义积分器的单相锁相环(SOGI-PLL)和相角补偿相结合的方法去改善波形畸变,同时提出了在固定采样频率下,基于拉格朗日插值法的有限脉冲响应(FIR)滤波器的自适应分数阶重复控制策略,来消除加入下垂控制频率波动造成的电压谐波分量。最后,搭建了实验平台对所提出的策略进行了验证,实验结果表明优化后的策略可以改善逆变器输出电压波形畸变并减小电压谐波,提高了电能质量。

HERIC inverter is widely used in single-phase photovoltaic storage systems due to its low leakage current and high efficiency.However,frequency fluctuations caused by droop control when multiple photovoltaic storage inverters connected in parallel under non unit power factor modulation,will result in problems such as increased inverter output voltage harmonics and waveform distortion.Aiming at this problem,a strategy combining single-phase phaselocked loop based on second-order generalized integrator(SOGI-PLL),and phase angle compensation is proposed to improve waveform distortion and an adaptive fractional order repetitive control strategy based on Lagrange interpolation for finite impulse response(FIR)filters at fixed sampling frequencies is proposed to eliminate voltage harmonic components caused by droop control frequency fluctuations.Finally,an experimental platform is built to validate the proposed strategy.Experimental results show that the modified strategy can improve output voltage waveform distortion of the inverter,and decrease output voltage harmonics,improve the power quality.