基于交替单相PWM控制的三相光伏并网系统  

Three-phase PV grid-connected system based on alternating single-phase PWM control

作　　者：李小燕[1] 张代润[1] 李媛[1] 许扬[1] 

机构地区：[1]四川大学电气信息学院,四川成都610065

出　　处：《可再生能源》2012年第5期10-13,17,共5页Renewable Energy Resources

摘　　要：提出了可用于多支路型三相光伏并网逆变器的交替单相PWM控制方法。该控制方法在一个工频周期内,逆变器有6种开关模式,每种开关模式中只须对三相中的一相桥臂进行PWM控制,从而有效降低了功率管开关损耗,在多支路光伏并网结构提高能量转换效率的基础上,进一步提高系统效率。采用电流滞环PWM跟踪控制,能够简单实现逆变正弦电流输出,跟踪性能好,并网功率因数为1,系统稳定性好,电流总谐波畸变率(THD)较低,可满足并网要求。通过Matlab仿真验证了该控制方法的正确性和有效性。A novel alternating single-phase PWM control method,which can be applied to multi-string three-phase PV grid-connected inverter,is proposed.In the alternating single-phase PWM method,the inverter has six switching modes in one power frequency period.Only one of the three-phase legs is switching based on PWM control in each switching mode.Therefore,the switching loss of the power devices is reduced effectively.The system efficiency is improved further under the condition that multi-string PV grid-connected construction can improve energy conversion efficiency.Current hysteresis PWM tracking control can easily realize sinusoidal output current of inverter with good tracking performance.United power factor of grid-connected current can be obtained and the system has good stabilization.The current total harmonic distortion（THD） is lower and acceptable.The results of Matlab simulation prove the validity of the control method proposed.

关 键 词：光伏并网 逆变器 滞环PWM控制 开关损耗 多支路 

分 类 号：TK514[动力工程及工程热物理—热能工程]