单相三电平整流器的SVPWM与中点电位控制方法

Implementation of Space Voltage PWM Method and Neutral-Point Voltage Control for Single-Phase Three-Level Rectifiers

通过分析单相电压型三电平中点钳位(NPC)整流器的工作原理、传统单相三电平空间电压矢量调制(SVPWM)和中点电位控制方法的缺点,提出了一种改进的SVPWM算法和中点电位控制方法,并进行了计算机仿真和小功率实验样机试验.理论分析、计算机仿真和试验结果表明:在保证开关频率恒定的情况下,该SVPWM算法开关损耗小,输出PWM脉冲具有对称性,可使交流侧电流的高次谐波分布在2倍开关频率附近,且易于用DSP(数字化处理器)实现;无论负载是否变化,该中点电位控制方法均能有效解决中点电位不平衡的问题,具有较强的抗干扰能力,且易于实现.

An improved SVPWM （space voltage pulse width modulation） method and a novel neutral- point voltage control method were proposed by analyzing the operating principle of single-phase three- level NPC （neutral-point-clamped） voltage-source rectifiers and the disadvantages of the conventional single-phase three-level SVPWM and the neutral-point voltage control method. In addition, a computer simulation was done, and a low power prototype was designed and implemented. The theoretic analysis, computer simulation and experiment results show that in the condition of a constant frequency, the SVPWM method can obtain litter switch wasting and symmetric PWM drive signals, the high harmonic frequencies of the line current is close to twice switch frequency, and the method is easy to implement in DSP （digital signal processor）. Whether the load is variational or constant, the proposed neutral-point voltage control method can solve the neutral-point voltage problem effectively and resist disturbance strongly, and it is easy to implement.