光伏离网逆变器并联控制系统研究

摘要

为解决单台光伏离网逆变器容量小、可靠性低和传统逆变器并联动态性能差的问题,设计一种并联控制方法.通过对光伏离网逆变器并联功率模型的分析,基于无互联线的有功和无功功率PQ下垂特性改进的并联控制算法,量化有功功率、无功功率与输出电压幅值、相位之间的关系,运用双闭环的控制策略,设计基于DSP并联控制系统,实现逆变器并联均流控制的数字化,并搭建基于TMS320F2809的两台4 kVA逆变器无互联线并联硬件平台进行实验分析.实验结果表明:系统的并联均流效果良好,可提升光伏逆变系统的容量,提高动态性能.%A parallel control method is designed in view of low capacity and low reliability of single set PV off-grid inverter and low parallel dynamic performance of traditional inverter. The parallel control algorithm based on the analysis on the parallel power model of PV off-grid inverter and improved PQ droop characteristic of active and reactive power without interconnection line is employed to quantify the relations between active power, reactive power and output voltage amplitude and phase. With the aid of dual closed-loop control tactics,the design of parallel control system based on DSP is applied to realize the digitization of inverter parallel current sharing control,and the interconnection line-free parallel hardware platform of two 4kVA inverters based on TMS320F2809 is set up for experimental analysis. The experimental results show that the parallel current sharing system works,which is instrumental in the improvement of the capacity of PV off-grid inverter system and the enhancement of the dynamic performance.