【摘要】 中性点电位平衡问题是三电平逆变器在应用过程中需要考虑的一个重要问题,中性点电位不平衡不仅会增加功率开关器件的电压应力,并且在有源逆变的应用场合会造成逆变失败。首先建立三电平逆变器的数学模型,详细分析了空间矢量脉宽调制的特性和中性点电位失衡的原因,在此基础上研究了一种基于空间矢量切换技术的中性点电位平衡策略,根据实时直流电容电压和交流电流,通过正负小矢量进行等效切换完成对当前PWM信号的修正,从而实现中性点电位达到平衡状态,仿真结果验证了该方法的正确性。更多还原

【Abstract】 Neutral point potential balance is an important problem in design of three-level inverter,the imbalance of neutral point potential not only increases voltage stress of power device,but also results in inversion failure in the active inversion situation.In this paper,a mathematical model of three-level inverter is presented,and the theory of the space-vector pulse-width modulation method and the causes of neutral point potential imbalance are analyzed.Then a neural point potential balance method based on space-vector switching technology is proposed,in which the revision of the current PWM signal is completed through small voltage vector equivalent switching according to the measurement of voltage and AC current of two capacitors,leading to the neutral point potential balance.Simulation results verify the feasibility of the proposed method.更多还原