两类离网光伏控制器外特性比较分析

Comparison and analysis in the out properties of two kinds of off-grid PV controller

对串联PWM型和软开关MPPT型离网光伏控制器的外特性进行了比较分析,给出了两类光伏控制器在不同阶段的电压输出波形。由于对峰值电压的受控特性不同,造成串联PWM控制器比软开关MPPT控制器的蓄电池寿命短。通过仿真得到两类光伏控制器输出功率随蓄电池电压、日照强度和温度的变化曲线。在标准条件下软开关MPPT型控制器比串联PWM型控制器的输出功率平均多26%。随着日照强度的增加或随着温度的降低,两种控制器外特性的差别更大。

The out properties are compared and analysed between serial PWM and soft switching MPPT off-grid PV controller by measurement and simulation.The out voltage waveforms in different stages of the two kinds of PV controller are given.It is pointed out that the batteries＇ life of serial PWM controller is shorter than that of soft switching MPPT controller due to their different controlled properties of the peak voltages.Two kinds of the PV controller＇s mathematical models are given.The output power curves varied with battery voltage,irradiance and temperature are calculated by emulation mode.The result shows that the output power of soft switching MPPT controller is averagely 26% higher than that of serial PWM controller under the standard conditions.The difference will be bigger with the higher irradiance or lower temperature.