适应机车功率波动特性的高压铁路功率调节器控制策略

Control Strategy for High Voltage Railway Static Power Conditioner Adapting to Power Fluctuation Characteristics of Electric Locomotive

为了降低降压变压器的安装空间及磁饱和等因素给铁路功率调节器(railway static power conditioner,RPC)工程应用及治理效果带来的不利影响,模块化多电平换流器的铁路功率调节器(railway static power conditioner of modular multilevel converter,MMC-RPC)成为研究热点。但现有的MMC-RPC控制策略没有考虑电力机车实际负荷功率及电流波动特性对MMC各子模块电容电压影响,使其电容电压波动较大。为此,根据电力机车功率及负荷运行特性,采用混合PWM调制策略,既能满足开关损耗低的要求,又能适应电力机车动态运行特性下MMC-RPC各子模块电容均压波动范围。最后,通过仿真和实验结果验证了MMC-RPC输出性能相对传统二电平RPC的优越性,采用的混合PWM调制策略能够使得MMC-RPC适应电力机车实际负荷功率及电流波动特性,各子模块电容均压波动幅值均有效控制在±5%范围内。

In order to reduce the adverse effects of installation space and magnetic saturation of the step-down transformer on the engineering application and governance effects of railway static power conditioner(RPC),the railway static power conditioner of modular multilevel converter(MMC-RPC)has become a research hotspot.However,the existing MMC-RPC control strategies do not consider the influence of the actual load power and current fluctuation characteristics of electric locomotives on the capacitance voltage of each sub-module of MMC,so that the capacitor voltage fluctuates greatly.Therefore,according to the power and load characteristics of electric locomotives,a hybrid PWM modulation strategy is adopted,which can not only meet the requirements of low switching loss,but also adapt to the fluctuation range of the capacitor voltage equalization of each sub-module of MMC-RPC under the dynamic operating characteristics of electric locomotives.Finally,the simulation and experimental results verify the superiority of the MMC-RPC output performance over the traditional two-level RPC.By adopting the hybrid PWM modulation strategy,the MMC-RPC can adapt to the actual load power and current fluctuation characteristics of electric locomotives,and the fluctuation amplitude of the capacitor voltage equalization of each sub-module is effectively controlled within the range of±5%.