Research on Flying Capacitor Voltage Balance Based on PI Control
With the development of new energy,the output of photovoltaic power generation accounts for an in-creasing proportion of China's total output of power generation.As an indispensable part of photovoltaic power gener-ation,photovoltaic inverter is often required to have high power density and high efficiency due to the limitation of site and other factors.Flying capacitor(FCML)multilevel topology can effectively reduce the volume of inductance,so it has a great prospect in the situation of high power density and high efficiency.However,during the actual oper-ation of the flying capacitor inverter,the voltage of the flying capacitor is often uneven.The uneven voltage of the flying capacitor will not only make the circuit lose the"frequency multiplication"effect,but also make the voltage stress at both ends of the switch tube unbalanced,resulting in the phenomenon of aircraft explosion.Therefore,this paper selects 7-level FCML as the experimental object,expands the grading ring based on PI control to 7-level FC-ML,and finally builds a 3kW prototype to verify the effectiveness of the grading ring based on PI control.
NETL
NSTL
万方数据
