高性能并网逆变器数字控制技术研究

Digital control of high -performance grid -connected inverters

研制了一台高性能数字化并网逆变器实验样机。在理论分析的基础上,建立了逆变器线性控制模型,并从线性系统叠加定理和频域分析角度提出实现零稳态误差正弦电流控制的条件。为了避免频率波动对控制器性能的影响,采用带通滤波器式(BPFM)控制器对并网逆变器输出电流进行控制,克服了传统PI控制器对正弦信号跟踪出现幅值误差和相位误差较大的问题。并网逆变器数字化控制采用TMS320LF2407DSP。实验结果表明,设计的并网逆变器数字控制具有控制精度高、输出电流谐波失真小等优点。

A high-performance experimental prototype of digital grid-connected inverter is developed. Its linear control model is built,based on which the conditions for implementing zero steady- state error control of sinusoidal reference signal is proposed,applying the superposition theorem and frequency- domain analysis. In order to mitigate the negative effect of the frequency fluctuation on controller,the output current is controlled by a BPFM（Band-Pass Filter Mode ） controller,which avoids the bigger amplitude and phase errors of traditional PI controller in sinusoidal reference signal tracking. The digital grid- connected inverter adopts TMS320LF2407 DSP. Experimental results show that the designed digital control of grid-connected inverter has high control precision and low current harmonic distortion.