三相光伏并网逆变器定频控制算法的研究与实现

摘要

In order to improve further the dynamic characteristic,as well as to realize the outputting unity power factor,based on research of thetopology prediction of three-level inverter and principle of work,the decoupled model of inverter was established in rotary two-phase coordinates. A control structure of double close-loop was constructed combined with coordinate transformation and control strategy of current decoupled. The value of the double-loop controller was given for reasonable parameters. The stability of the control structure of double close-loop was validated by frequency analysis.Regulating the switching frequency with SPWM modulation system, the simulation results and its analysis were given out to confirmthe correctness and validity of the design. The experimental verification platform was bulit with TMS320LF2407 processor and other circuit elements. The inverter side voltage and current waveforms were got under the condition of given switching frequency, respectively 2 kHz and 5 kHz. Through analysis of inverter output current waveform and PWM output waveform, the fixed switching frequency control strategy was proved feasible.%为了达到提高光伏并网逆变器动态性能的目的,以及实现单位功率因数输出的要求,从三相光伏并网逆变器的拓扑结构以及工作原理入手,建立了逆变器在两相旋转坐标系下的解耦模型.结合坐标变换和电流解耦控制策略构造了逆变器的双闭环控制结构,对控制器的取值给出了较为合理的参数,通过频率分析验证了双闭环结构的稳定性.采用SPWM调制方式对逆变器开关频率进行调节,通过仿真波形验证了固定开关频率控制算法的有效性.最后,利用TMS320LF2407搭建了实验验证平台,得到了在给定开关频率分别为2、5 kHz条件下的逆变侧电压电流波形,通过逆变器输出电流波形及PWM输出波形的分析,验证了固定开关频率控制策略的可行性.