基于双有源桥电路的氢能双源机车双向变流器设计与应用

Design and Application of Bidirectional Converter Based on DAB for Hydrogen Energy Dual-source Locomotive

氢能双源机车使用氢燃料电池供电,与传统内燃机车和电力机车相比,不仅更加安全环保,而且运行噪声小、成本低,维护也更加方便。双向DC/DC变流器作为氢能系统的关键部件,用于将燃料电池电压转换为系统所需的工作电压,但既有双向DC/DC变流器一般采用非隔离斩波电路,存在不能实现功率流动方向的在线切换、不能冗余工作等缺点,从而限制了其在氢能双源机车上的应用。为此,文章设计了一种双向隔离DC/DC变流器,其采用双有源桥(dual active bridges,DAB)电路,软开关范围宽,变换效率高,并可实现能量的双向流动和传输方向的在线切换,具备电气隔离和热冗余功能。文章具体阐述了一种440 kW双向隔离DC/DC变流器的主电路设计和控制策略,提出了一种以电感电流峰值最小化作为优化目标的储能电感设计方法。原理仿真和试验结果验证了该设计的可行性,变流器效率最高可达96%,成功实现了大功率双向隔离变流器在氢能机车的装车应用。

Compared with traditional diesel locomotive and electric locomotive,hydrogen energy dual source locomotive uses hydrogen fuel cell for power supply,which is not only safer and more environmentally friendly,but also has low operating noise,low cost and more convenient maintenance.As a key component of hydrogen energy system,bidirectional DC/DC converter converts fuel cell voltage into working voltage required by the system,but the existing bidirectional DC/DC converter generally adopts non isolated chopper circuit,which has the disadvantages of not realizing online switching of power flow direction,not redundant operation,etc.,thus limiting its application in hydrogen energy dual source locomotive.Therefore,this paper designs a bidirectional isolated DC/DC converter,which uses dual active bridge(DAB)circuit,has wide soft switching range,high conversion efficiency,and can realize bidirectional flow of energy and online switching of transmission direction,with electrical isolation and thermal redundancy functions.This paper describes the main circuit design and control strategy of a 440 kW bi-directional isolated DC/DC converter,innovatively proposes a design method of energy storage inductor,which takes the minimum of the peak current of inductor as the optimization objective.The feasibility of the design is verified through principle simulation and test.The converter efficiency can reach 96%,which successfully realizes the loading application of high-power bi-directional isolated converter in hydrogen locomotive.