Design And Implementation Of The Charge And Discharge Bi-directional DC/DC Power Conditioner

Bi-directional DC/DC power conditioner is the important component unit in DC micro-grid distributed power systems, performs as two DC/DC converters. In the ships power systems at sea, it charges batteries when new environmentally friendly fuel are enough, and makes batteries discharge to DC BUS when fuel are lack or fuel engine is prohibited used, which is significant. So this thesis researched and designed the20kW-discharge and10kW-charge bi-directional DC/DC power conditioner, which used DSPIC33F610as a controller, accepted orders from outside by CAN. The main contents are as follows:Firstly, based on explaining the power conditioner'function and specification, the main circuit design scheme was isolated full-bridge, and design ideas of each auxiliary circuit were analyzed.Secondly, analyzed the operating principle of the main circuit, brought start control way at charge and discharge mode separately, and described hardware circuits of auxiliary parts. Based on drive module, proposed a reliable and stable protective circuit.Thirdly, the mathematic model of the power conditioner was established through state-space averaged model, based on the model, PI controller is developed. MATLAB was used to simulate the controling system. Direct at discharge mode, designed discrete-time digital PI controller, which made duty cycle change stably, to prevent output voltage overshoot.Summarize the research and experiments, analyzed result and cause both in charge mode and discharge mode, finally tested the performance of the bi-directional DC/DC power conditioner.The results of this thesis show that the bi-directional DC/DC power conditioner has many characteristics.Such as good regulation ratio of the load, stabilized output, low output voltage ripple, fast response and timely protection. All of these show that the design meets the requirements of the power conditioner.