三电平逆变器中点电压偏移最小化的调制方法

A Modulation Method of a Three-level NPC Inverter with Minimum NP Potential Unbalance

简单阐述了三电平逆变器的空间矢量调制(SVM)和空间矢量脉宽调制(SVPWM)控制方法。由于P型和N型小矢量对中点电压具有较明显的影响,提出了一种用于二极管中点箝位(NPC)型三电平逆变器中点电压偏移最小化的方法,探讨了其控制原理,并详细论述了所提算法的实现过程。仿真和实验结果证明了该控制算法的有效性。最后在该调制方法的基础上,实现了基于零序分量叠加的SVPWM算法,以便更有效地抑制中点电压波动。

The traditional SVM algorithm and the SVPWM control method for three-level inverter are described briefly.Based on the fact that positive and negtive small vectors have an obvious effect on the neutral-point potential,a novel SVPWM method for the neutral-point-clamped three-level voltage source inverter with minimum NP potential unbalance is proposed.Then the control method of the SVPWM method is discussed.The implementation procedure of the SVPWM method mentioned is illustrated.Some work is given to the simulation of the SVPWM method and the experimental test of a prototype inverter with different modulation factors.The validity of the SVPWM method is verified by experimental results.Finally,a control algorithm with the zero-sequence signal injections is realized based on the SVPWM to improve the problem of NP potential unbalance further.