光伏高效软开关DC-DC变换器的数字化控制与实现

Digital Control and Implementation of Photovoltaic Soft-Switching DC-DC Converter With High-frequency Step-up Transformer Isolation

为满足三相光伏并网逆变器高输入电压的需求,克服其工频升压隔离变压器耗材严重的不足,本文提出了一种新型的高频变压器隔离升压软开关变换器,它通过两个升压绕组串联整流提高输出电压,一个降压绕组串联换流电感实现了全功率范围内变换器的软开关。文中首先分析了其工作原理,然后给出了一种非对称数字移相脉冲宽度调制控制策略和实现方法,最后设计并制作了工程样机。实验结果表明,该变换器控制方案合理,工作效率高。

To satisfy the need of the high input voltage in three-phase grid-connected photovoltaic（PV） inverter,overcome the shortage of power frequency isolation transformer severe material consumes.An improved boost-voltage phase-shifted full-bridge soft switching converter is presented.It has two step-up windings rectifiers in series and one step-down winding in series with a linear reactor.The former is used to increase the output voltage;the latter is used to ensure the devices soft switching in the full power scope.Firstly,its principle is analyzed with detail.Secondly,an asymmetrical digital phase-shift pulse width modulation（PWM） control scheme and the implement method are given.The last,the control software is designed,and a prototype is completed.Experimental results show that the control scheme is feasible,the converter has high efficiency.