A Compound Flyback Bi-Directional Current Source High-Frequency Link DC/AC Converter

In the ways of power energy production, battery is a common and important mode. Providing power energy to AC load with battery, the DC energy must be transferred to AC power. In many converters designed to put out 50Hz low frequency AC power, for the purpose of isolation and change voltage, there is no choice but to use 50Hz low frequency transformer. With the development of high frequency switching technique and the increasing needs of reducing the size and weight of power supply, the traditional PWM inverter circuit can hardly meet the needs. So it is possible that the high frequency transformer replaces the low frequency transformer. The traditional high-frequency link DC/AC inverter composes of three main parts, the high-frequency inverter, the high-frequency rectifying circuit and the low-frequency inverter. Because of the two power transfer levels, the efficiency of this converter is not high. In the topology of traditional high-frequency link DC/AC inverter, there is a high-frequency rectifying part, so the power only can be transferred from the power supply to the load. When the load consists of var power, the inverter cannot work properly.A current source bi-directional high-frequency link DC/AC converter is proposed in this paper. Using the high frequency transformer, the voltage transform, isolation and low power transmission can all be achieved. This converter has the properties of simple topology, less components and high reliability. It can satisfy the need of low power application systems. The topology of the converter consists of a compound flyback converter, a high frequency transformer and a bi-directionalrectifying and chop circuit. The control scheme is using SPWM modulation method to control the compound flyback bi-directional current source high-frequency link DC/AC converter and using the voltage instantaneous value feedback to control the converter which works in chop mode. By this means the power can be feedback from the load to the power, so this converter can achieve the bi-direction power transfers and fit the requirement of all kinds of load including resistant, inductance and capacitive loads.The operation principles, operation modes and the control schemes of the proposed system are thoroughly analyzed and discussed in detail. The simulation results of the compound flyback bi-direction current source high-frequency link DC/AC converter topology is also given to verity the above description.