DC-DC converter is a solution to solve the system efficiency, especially the efficiency of high-power systems. It is a kind of power electronic device that converts DC electrical energy into DC electrical energy which is controlled by voltage or current required by load. It cuts the constant DC voltage into a series of pulse voltages by fast on-off control of power electronic devices. The average value of output voltage can be adjusted by changing the duty cycle. The output filter is used to get the current or voltage controllable DC power.