基于PWM分解的三电平逆变器SVPWM的DSP实现方法

THREE-LEVEL SVPWM METHOD BASED ON TWO-LEVEL PWM CELL IN DSP

三电平技术在电力输电及中高压变频场合有着广泛的应用前景。文中讨论了三电平逆变器的空间矢量控制技术和基于中点电流方向的中点电压平衡方法,根据矢量控制与载波技术的内在联系,提出了矢量控制的分解方法。利用面向控制的DSP芯片(TMS320LF2407A)内部集成的2组三相两电平载波PWM单元,实现了三电平的矢量控制技术。该方法充分利用DSP的内部资源,以单片DSP实现三电平电路的矢量控制,大大降低了控制电路硬件的复杂性,提高了系统的可靠性。实验证实所提出的方案切实可行、效果显著。

Three-level converter technique has attracted greater attention and interests recently due to its higher potential in applications. This paper discusses the method of the space-vector pulse width modulation (SVPWM) and mid-voltage balance based on direction of mid-current for three-level converters. Based on decomposition of the SVPWM, a method based on DSP is proposed. The method adopts two groups of three-phase traditional PWM cell integrated in DSP. It implements all control functions by only a single DSP chip. The method utilizes the resource of DSP sufficiently, reduces the complexity and improves the reliability of system, which is well demonstrated in the paper by experiment results.