三相逆变器统一空间矢量PWM实现方法

Unified Space Vector PWM Implementation Method for Three-Phase Inverters

通过分析空间矢量脉宽调制(SVPWM)和载波PWM方法之间的内在关系,建立了包含各种连续和不连续SVPWM及SPWM方法的显性调制函数表达式,从而提出了基于载波的统一SVPWM实现方法。并且,在此基础上提出了一种三相逆变器统一SVPWM快速算法。该算法直接利用三相参考电压瞬时值计算PWM信号的开关状态切换时间,不需进行坐标变换、三角函数运算、扇区判断和有效矢量作用时间的计算等,因此更易于各种SVPWM方法的数字化实现。最后,对三相逆变器在SPWM和各种SVPWM控制方式下的输出电压谐波特性进行了对比分析。仿真和实验结果表明本文提出的三相逆变器统一空间矢量PWM实现方法是可行的和有效的。

The relationship between space vector pulse width modulation （SVPWM） and carrier-based PWM methods is comprehensively analyzed. The explicit modulation function expression, in which various continuous and discontinuous SVPWM strategies are intuitively embodied, is established, and a unified carrier-based SVPWM method is presented. Furthermore, a unified SVPWM fast algorithm for three-phase inverters is proposed. The proposed algorithm calculates the actual gating times for each inverter leg directly by use of three-phase reference voltages and needn＇t complex coordinate transformations, trigonometric function calculations, sector number identification, and the recombination of actual gating times, so it can be more easily implemented with a microprocessor compared with SVPWM conventional algorithm. At last, the output voltage harmonic characteristics of the three-phase inverter under the SPWM and various SVPWM control are investigated. The simulation and experimental results show that the unified SVPWM implementation method for three-phase inverters is feasible and valid.