基于载波的三电平中点电压平衡控制策略  

A Three-Level Neutral Point Voltage Balance Control Strategy Based on Carriers of SPWM

作　　者：龚博[1] 程善美[1] 秦忆[1] 

机构地区：[1]华中科技大学控制科学与工程系,武汉430074

出　　处：《电工技术学报》2013年第6期172-177,共6页Transactions of China Electrotechnical Society

摘　　要：中点电压平衡问题是二极管钳位式三电平逆变器的固有问题,本文对此进行了深入探讨,分析了中点电压失衡的原因,从载波的角度研究了载波幅值变化对中点电压的影响,推导出中点电压波动和调制比、调节量、功率因数之间的关系,讨论了调节量、功率因数对中点电压波动的影响,提出了一种基于载波变幅的SPWM调制策略,通过保持调制波不变,改变载波的幅值来实现中点电压平衡控制。最后在基于DSP的二极管钳位型三电平逆变器试验平台上验证了上述调制方案的有效性。The neutral point voltage balancing problem is the inherent problem of the diode clamped three-level inverter. A detail discussion is presented in this paper. The causes of the unbalancing neutral point voltage are analyzed, and the impact on the neutral point potential of the carrier＇s amplitude is studied. The relationship among neutral point voltage variation, modulation index, power factor, and regulation coefficient is investigated in detail, and the influence of the regulation coefficient and power factor on neutral point voltage variation is discussed. Then an amplitude-scaled SPWM modulation scheme is proposed, and the neutral point voltage is controlled balance by changing the amplitude of carriers without changing the modulation waves. The validity of the modulation scheme is verified on the DSP-based diode clamped three-level inverter platform.

关 键 词：三电平逆变器 中点电压平衡 载波变幅 SPWM 

分 类 号：TM464[电气工程—电器]