Research on High-efficiency Bidirectional dc-dc Converter for dc Distribution System

研究了一种用于二次电池、双电层电容器等储能系统的高效隔离型全桥双向DC/DC转换器。该变流器由低压侧电流型变流器、高压侧电压型变流器、两者之间的高频变压器和抑制电流换相过压的有源钳位电路组成，实现了开关器件的软开关。通过数值仿真，验证了该变流器各开关器件在升压和降压模式下的软开关。我们还使用了一个1kW的DC-DC转换器进行了实验，该转换器是直流配电系统中假设转换器的千分之一。该变流器采用IGBT智能功率模块作为开关器件，以数字信号处理器(DSP)和现场可编程门阵列(FPGA)作为控制器件。所有开关器件的软开关均为DEM…通过实验对Boost和Buck两种工作模式进行了比较，实验测得Boost模式的转换效率为83.3%，Buck模式下的转换效率为83.1%。根据损耗分析的结果，在假定变压器和电抗器的效率合理的前提下，1 MW变流器的效率估计在95%以上。此外，还对EDLC作为储能装置进行了研究。对EDLC采用了三级梯形等效电路，并推导了其传递函数。为了确定等效电路的参数，我们进行了恒流充放电实验和电阻放电实验，并将实验结果与数值模拟结果进行了比较。结果表明，在恒流工作时，三级梯形等效电路能很好地模拟实际的EDLC，而单级梯形等效电路在电阻放电实验中表现出较好的一致性。较少

A high-efficiency isolated-type full-bridge bidirectional dc/dc converter, which is employed for energy storage systems such as secondary batteries and electric double layer capacitors (EDLCs), is investigated. This converter consists of a low-voltage-side current-type converter, a high-voltage side voltage-type converter, a high frequency transformer between them, and an active clamp circuit fir suppression of overvoltage due to current commutation and realization of soft switching of switching devices.With a proposed novel control method, soft switching of every switching device of the converter was confirmed in both boost and buck operation modes through numerical simulation. We also carried out experiments using a 1 kW dc-dc converter that is a thousandth scale of an assumed converter in a dc distribution system. The converter employed an Intelligent Power Module of IGBTs as switching devices, and DSP and FPGA as control devices. Soft switching of all the switching devices were dem … More onstrated in both the boost and buck operation through the experiments.The measured conversion efficiencies are 83.3% in the boost operation and 83.1% in the buck operation, respectively. According to the results of loss analysis, the efficiency of the assumed 1 MW converter is estimated to be more than 95% on the assumption of reasonable efficiency of the transformer and reactors.In addition, the EDLC is investigated as an energy storage device. We employed a three-stage ladder type equivalent circuit for the EDLC, and derived its transfer function. To determine the parameters of the equivalent circuit, we conducted constant current charge and discharge, and resistor discharge experiments, and compared the results of experiments and numerical simulations. As a result, we found that the three-stage ladder type equivalent circuit well simulated the actual EDLC in the constant current operation, however the single-stage ladder-type equivalent circuit showed good agreement in the resistor discharge experiment. Less