电气化铁道用多电平电能质量调节器及其控制研究

摘要

电气化铁道是直接接入高压电力系统的一个特殊用户,其负荷具有非线性、非对称性和波动性等特点.以沪杭电气化铁路某牵引变电所为研究对象,针对电气化铁道谐波、无功和负序电流的综合治理要求和特点,提出了一种新型的多电平电能质量调节器(MPQC).这种新型的电能质量调节器主要由共用直流侧电容的两组单相多电平逆变器组成,每组逆变器由两个直流侧电压为3∶1的H桥逆变器级联而成,通过电网变压器与牵引电网联接.通过分析多电平调节器的电能质量调节特点,提出了适用于单相多电平逆变器的多电平直接脉宽调制方法(MDPWM),应用了基于逆变器两侧能量平衡的多电平逆变器控制方法.仿真结果证明了这种新型的多电平电能质量调节器的可靠性较高,能同时补偿牵引电网的上、下行供电臂,满足对电气化铁道的电能质量综合治理要求,能获得良好的补偿效果.%As a particular user to power system, electrified railway connects to high-voltage power system directly, with the characteristics of non-liner, asymmetry and volatility, etc.According to the requirements and characteristics of comprehensive management of harmonies, reactive power and negative sequence currents in a certain traction substation of Shanghai-Hangzhou Electrified Railway, this paper proposes a novel Multi-level Power Quality Compensator(MPQC).This novel MPQC is composed of two single-phase cascaded inverters by sharing the DC capacitors.Each cascaded inverter is made of two cascaded H-bridge inverters and the ratio of the DC voltage is 3:1, then, connects to traction power system via grid-transformer.By analyzing the working principle of the MPQC, and researching on the Multi-level Direct Pulse Width Modulation (MDPWM) method for single phase multi-level inverter, this paper presents multi-level inverter control strategy based on energy balance.Simulation results prove this novel MQPC is reliable, can compensate the both feeders in traction power system simultaneously, and also can manage the power quality of the electrified railway comprehensively to achieve satisfactory compensation effects.