单相动态电压恢复器控制策略研究

Research on Control Strategy of Single-phase Dynamic Voltage Restorer

长期以来电压暂降会引起用电设备的不正常工作,影响诊断、治疗、手术的进行,甚至会危及病人的生命。如果电压暂降发生在通信行业,会中断通信,给人们造成巨大的经济损失。为了解决微电网电压暂降和低电压的问题,动态电压恢复器(DVR)是串接于电网与负载之间用以实现快速补偿系统电压暂降的电力电子装置。基于一种新型单相半桥Ⅰ型三电平逆变器拓扑,对单相DVR的整流器与逆变器控制策略分别进行研究,利用比例积分(PI)控制器对逆变器电流内环和整流器电压外环进行反馈控制,利用准比例谐振(QPR)控制器对逆变器电压外环和整流器电流内环进行反馈控制,推导单极性正弦脉宽调制(SPWM)的发波原理。最后通过仿真验证了控制策略的可行性,通过搭建20 kVA的单相DVR实验样机,对其合理性和有效性进行了验证。

For a long time,voltage sag will cause abnormal operation of electrical equipment,affect diagnosis,treat-ment,operation,and even endanger the lives of patients.If the voltage sag occurs in the communications industry,communications will be interrupted,causing huge economic losses to people.In order to solve the problems of voltage sag and low voltage in the microgrid,a dynamic voltage restorer(DVR)is a power electronic device connected in se-ries between the micro grid and the load to quickly compensate for the system voltage sag.Based on a new single-phase half-bridge I-type three-level inverter topology,the rectifier and inverter control strategies of the single-phase DVR are studied separately,and a proportional integral(PI)controller is used to feedback control the current inner loop and the rectifier voltage outer loop,and the quasi-proportional resonance(QPR)controller is used to feedback control the inverter voltage outer loop and the rectifier current inner loop,and the principle of unipolar sinusoidal pulse width modulaton(SPWM)wave generation is derived.Finally,the feasibility of the control strategy is verified by simulation,and its rationality and effectiveness are verified by building a 20 kVA single-phase DVR experimental prototype.