电力电子牵引变压器中单相PWM整流器准PR控制策略

The quasi-PR control strategy for single-phase PWM rectifier used in power electronic traction transformer

电力电子变压器(Power Electronic Transformer,PET)装备在电力机车中可以满足牵引系统减重、改善电能质量等多种要求。单相脉宽调制(Pulse Width Modulation,PWM)整流器作为电力电子牵引变压器的重要组成部分,具有功率因数可控、动态响应较快的优点,但由于输出直流电压的低频波动,使其输入交流电流中产生低次谐波"污染",恶化电能质量。为此,论文为电力机车牵引系统的单相PWM整流器提出一种改进的矢量控制策略,将比例谐振(PR)控制引入电流控制环,并在分析网侧谐波电流产生原因的基础上,将低次谐波抑制功能引入到电流环控制器中,以抑制网侧电流谐波。仿真分析与实验结果验证了所提出控制策略的有效性。

Power electronic transformer（ PET） which is equipped in electric locomotive can meet the requirements of weight loss,improving power quality for traction system. Single-phase pulse width modulation（ PWM） rectifier is an important part of power electronic traction transformer,with the advantages of controllable power factor,fast dynamic response. However,due to the low-frequency fluctuations in the DC voltage,AC current will generate low-order harmonics which will ＂pollute＂the traction network and worsen the power quality. Therefore,this paper proposed an improved vector control strategy for the single-phase PWM rectifier of the electric locomotive traction system,the proportional resonant（ PR） control is introduced in the current control loop,and based on the analysis of the reason for the harmonic current produced in the network side,harmonic suppression function is introduced into the current loop controller to suppress the harmonic current. Simulation analysis and experimental results verify the effectiveness of the proposed control strategy.