三电平逆变器空间矢量脉宽调制算法及中点电位平衡控制方法的改进

The Improvement for the SVPWM Algorithm and Midpoint Potential Balance Control Method of Three-level Inverter

针对T型三电平并网逆变器三电平空间矢量脉宽调制算法(SVPWM)及中点电位平衡策略,为降低SVPWM数字化的运算量,本文提出一种基于单载波的快速简化SVPWM算法。该算法无需复杂的扇区判断和三角函数计算,将三相正弦参考电压直接转换到两电平矢量空间,采取两电平统一PWM方法实现三电平SVPWM等效调制波和开关函数输出。为控制中点电位平衡及不同矢量调整策略对中点电位的影响,获得一种简单快速的平衡控制方法。仿真验证了快速简化SVPWM算法的正确性和有效性,并能够实现对中点电位的平衡控制。

For the T-type three-level grid-connected inverter control system,this paper mainly studied the three-level space vector pulse width modulation algorithm and its midpoint potential balance strategy.In order to reduce the computational complexity of SVPWM digitization,a fast and simplified SVPWM algorithm based on single carrier was proposed.It could convert three-phase sinusoidal reference voltage directly into two-level vector space without taking complicated sector judgment and trigonometric function calculation.The flat unified PWM method implemented a three-level SVPWM equivalent modulation wave and a switching function output.In order to control the midpoint potential balance,the influence of different vector adjustment strategies on the midpoint potential was analyzed,and a simple and fast balance control method was obtained.The simulation results verified the correctness and effectiveness of the SVPWM algorithm and simplify the balance control of the midpoint potential.