电网谐波下并网逆变器功率脉动抑制策略

电网电压中常含有一定的5次、7次谐波,导致并网逆变器输出功率产生6倍频脉动。为提高并网逆变器的运行性能,采用了一种基于谐振调节器的直接功率脉动控制策略,以实现并网逆变器输出有功功率和无功功率无波动的目的。基于瞬时功率理论,通过改变注入系统的有功和无功电流分量,结合谐振控制器抑制功率振荡。改进后的系统工作时无需获取谐波电流与电压的正负序分量,简单实用。基于1kW光伏并网逆变器实验平台对控制策略进行验证,实验结果表明,此控制策略能有效提高光伏并网逆变器的系统动态和稳态性能。

Power pulsation control strategy for grid-connected inverter under harmonically distorted voltage conditions

A certain 5^th or 7^th harmonic voltage in the grid will result in 6 times output power ripple of the grid-connected inverter. In order to improve the performance of the grid-connected inverter, a direct power pulsation control strategy based on resonant controller is proposed in this paper to achieve smooth active power and reactive power output. On the basis of instantaneous power theory, through changing the active and reactive current with a power pulsation compensation loop, and combing resonance controller, the power pulse component of the grid-connected inverter is controlled. The simple and useful system can directly suppress the output active and reactive power fluctuation and improve the system dynamic and static performance without considering phase decomposition of harmonic current and voltage. The correctness and effectiveness of the control strategy are proved by a 1 kW grid-connected inverter experiment system.