级联多电平技术在动态电压恢复器中的研究

Cascade Multi-level Technology for Dynamic Voltage Restorer

为了改善电压跌落引起的电能质量降低,分析了电压移位脉宽调制技术后,设计了一种应用十一电平级联逆变结构的无串联变压器的动态电压恢复器(DVR)。该技术基于同相位(IPD)电压移位调制方式对级联逆变结构进行调制,系统采用了改进的"abc-dq"变换检测算法准确、快速检测系统电压的幅值和相位准确,并采用最小电压补偿策略补偿电压跌落。仿真结果表明,该技术提高了逆变器的开关频率,谐波失真小、电压变化率低,完全满足DVR对高电压质量要求的需要。

The voltage-shifted pulse width modulation technology is researched and the transformer-less DVR which applies 11-level cascaded structure based on in-phase disposition （IPD） voltage shifted modulation technology is designed. An improved ＂abc-dq＂ transaction detection algorithm which can detect the system voltage amplitude and phase accurately and rapidly is used in the system, and the minimal voltage compensation strategy is adopted to compensate voltage drop. The simulation results by the Matlab/Simulink software show that, the 11-level cascaded Hbridge transformer-less DVR based on voltage shifted pulse width modulation technology can greatly increase the inverter switching frequency, and decrease the harmonic distortion and voltage rate of change, thereby it fully meets the high quality requirements of vohage. The application of this technology can greatly enhance the performance indicators of DVR and has a high practical value.