基于准Z源变换器的混合微电网及其协调控制

Hybrid Micro-grid Based on Quasi-Z-source Converter and Its Coordination Control

针对常规交直流混合微电网直流母线电压必须高于交流母线电压的问题,研究一种新型交直流混合微电网。直流母线和交流母线采用准Z源DC/AC双向变换器连接,利用Z源网络的升压功能降低直流母线的电压,实现了合理的电压匹配,适合于低压直流微电源和低压直流负载占主导的情况。Z源DC/AC变换器不需要插入死区时间,提高了微电网的可靠性。介绍了微电网的结构,建立了各部分的数学模型,给出并网和孤岛模式下的协调控制策略。最后利用仿真结果证明了新型微电网的可行性及其协调控制的有效性。

Since DC bus voltage of conventional hybrid AC/DC micro-grid has to be higher than its AC bus voltage,this paper proposed a novel hybrid AC/DC micro-grid.The DC bus and AC bus were connected via a quasi-Z-source bidirectional DC/AC converter,and the DC bus voltage was lowered by use of the voltage-boosting function of the Z-source network so as to realize rational voltage match.That approach was suitable for the case where the low-voltage DC micro source and low-voltage DC load held a dominant position.Furthermore,the reliability of the micro-grid was raised,as dead time was not needed for the operation of the Z-source DC/AC converter.This paper introduced the structure of the micro-grid,established mathematical models for each part and presented coordination control strategies for grid connection mode and island mode.Simulation results verified the validity of the novel micro-grid and the effectiveness of its coordination control.