一种采用混合控制策略的反激型光伏微逆设计

Design of Flyback Photovoltaic Micro Inverters Using Hybrid Control Strategy

微型逆变器可直接与光伏(PV)板连接,具有结构简单、体积小、输入输出隔离等优点。为了扩展PV微逆功率范围,前级DC/DC部分可采用两个反激变换器交错并联。首先分析了反激变换器的工作原理,针对传统工作模式下反激变换器不同控制策略的功率密度与损耗等方面存在不足,设计了一台具有主从关系的临界导通模式(BCM)和断续导通模式(DCM)混合控制的微型逆变器,该控制策略可提高PV微逆的稳定性和转换效率。根据电网相位和输出功率的变化选择不同的控制策略,弥补单一控制策略下存在的不足。最后搭建了一台350 W的交错并联反激微型逆变器样机进行实验测试,实验结果验证了该控制策略的有效性与可行性。

The micro inverter can be directly connected to the photovoltaic(PV)board,and has the advantages of simple structure,small size and input output isolation.In order to expand the PV micro inverter power range,the front stage DC/DC section can be used two flyback converters in staggered parallel.Firstly,the working principle of the flvback converter is analyzed,in response to the shortcomings of power density and loss of different control strategies of flyback converter in traditional working mode,a micro inverter with a master-slave relationship of mixed control of critical conduction mode(BCM)and intermittent conduction mode(DCM)is designed,this control strategy can improve the stability and conversion efficiency of PV micro inverter.Select different control strategies based on changes in grid phase and output power to compensate for the shortcomings of a single control strategy.Finally,a 350 W interleaved parallel flyback micro inverter prototype is built for experimental testing,and the experimental results verified the effectiveness and feasibility of the control strategy.