Design and Simulation of a Kind of Wide, High Input Voltage DC-DC Converter for PV

摘要

The working power of smart PV combined box need low voltage DC power. Taking power directly from photovoltaic modules, it can reduce costs and shorten the distance. But the high voltage of the PV module string converting to the low voltage of the smart PV combined box has many contradictions between the efficiency and the cost [1] . Therefore, a topologies--Series Connection Flyback (hereinafter referred to SCFlback) of ultra-wide input voltage converter was proposed in this paper by using two low-voltage power MOSFETs to achieve the bearing of ultra-voltage. Compared with the existing converter topology StackFETTM which is suitable for ultra-high input voltage, Smart PV combined box adopts the method of the series of the two converter so that the duty cycle is not smaller than the topology StackFETTM which is working in the similar status [2] , and it has a higher converter efficiency. Compared with the double-ended flyback topologies, flyback topology of its duty cycle can be more than 0.5, which is extremely useful for wide input. What’s more, the topology of the magnetic device, and the design of driving circuit and auxiliary power is very similar with the common Flyback converter which greatly decreases the time and difficulty of the design [3] .