基于混合模块化多电平变换器的储能铁路功率调节器及其控制策略

Railway power conditioner with energy storage system based on hybrid modular multilevel converter and its control strategy

针对电气化铁路系统具有负序、无功补偿能力和回收制动能量功能的装置存在成本高、控制不灵活的问题,本文提出了一种基于混合模块化多电平变换器(HMMC)的储能铁路功率调节器(RPC)拓扑及其控制策略。该拓扑可以灵活配置模块化多电平变换器各桥臂的储能子模块数目,同时储能子模块中RPC侧半桥变换器和储能系统侧半桥变换器控制独立,具有成本低、控制简单的特点。通过改进补偿电流指令生成方法,对储能电池采用直接电流控制并在均衡控制中前馈电池电流信息,能够灵活独立地控制各储能子模块的储能功率并维持子模块电容电压稳定;通过储能功率调配策略给定各储能子模块储能功率以充分利用储能系统容量,实现了负序、无功补偿和机车制动能量存储的目的。仿真结果验证了拓扑和控制策略的正确性和有效性。

In order to alleviate the shortcomings of high cost and inflexible control of equipment that is capable of compensating negative sequence current,reactive power and storing regenerative braking energy in the electric railway system,a railway power conditioner(RPC)with energy storage based on hybrid modular multilevel converter and its control strategy are proposed.For this topology,the number of energy storage sub-modules in each arm can be flexibly configured.Meanwhile,the half bridge converter on the RPC side and the energy storage system side in the energy storage sub-module can be controlled independently.Therefore,the proposed topology has low cost and simple control.The power of each energy storage sub-module can be independently controlled and the capacitor voltages of the sub-modules can be well balanced by improving the reference compensation current calculation method,adopting the direct current control for battery control and battery current feedforward control in balancing control.The reference power of each energy storage sub-module is given by the energy storage power allocation strategy to make full use of the energy storage system capacity.At the same time,the functions of compensating negative sequence current,reactive power and storing the regenerative braking energy of the locomotive are realized.The correctness and effectiveness of the topology and control strategy are verified by the simulation results.