单相光伏并网逆变器控制策略研究与设计

Research on Single Phase Photovoltaic Grip-Connected Inverter Control Strategy

针对光伏并网逆变器并网后其本质上为电流源的特点,采用STM32F103VET6型ARM芯片作为系统的控制核心,制造了一台5 kW单相光伏并网型逆变器。采用了固定开关频率的电流瞬时值控制技术来实现对并网电流的控制,在控制策略中加入了电压前馈来抑制电网电压对逆变器输出电流的影响,使用二阶电流预估来抵消SPWM波形延时对系统控制的影响。并且优化了最大功率点跟踪(MPPT)。实验证明,该逆变器样机性能完全达到设计要求。

The nature of the photovoltaic inverter is a current source.The 5 kW single-phase photovoltaic grid-connected inverters used STM32F103VET6-ARM chips as the control core of the system.With the current instantaneous value control technology of fixed switching frequency to achieve grid-current controlling,added voltage feed-forward in the control strategy to control the grip voltage to the inverter output current influence.Using second-order current estimate to offset the effect of delay of SPWM waveform to system control,and optimize the maximum power point tracking（MPPT）.Experiments show that the inverter prototype performances fully meet the design requirements.