微型光伏并网逆变器的研究

Research on micro-inverter for grid-connected photovoltaic system

研究了单级反激式变换电路在单相光伏并网微型逆变器中的工作原理及控制方式,引入了有源箝位软开关技术提高整机变换效率,采用双路交错并联的电路结构降低输出电流纹波,降低入网电流THD。对微逆变器进行了详细的小信号闭环系统建模、分析和控制方案设计。利用孤岛检测技术保护脱网状况下的逆变器的安全运作,使用飞思卡尔数字信号处理器作为全数字闭环控制策略的核心控制芯片。saber软件仿真及制作的1台200 W实验样机验证了该方案的可行性与高效性。

The working principle and control mode of the single-stage flyback converter circuit in the single-phase grid- connected photovoltaic （PV） system is studied. The technology of active clamp soft switch is applied to improve tlae conversion efficiency,and the output ripple current is decreased with the application of two-way interleaved circuit. The small-signal mode and control method of inverter is built and analyzed in detail. With the reduction of grid current THD,the safe operation of the inverter is ensured on off-grid status as the result of the participation of islanding detection technology, and the Freescale digital signal processor is introduced as the core control chip of the digital closed loop control. The saber software simulation together with an assembled 200 W experimental machine testified the feasibility and high efficiency of the technology.