基于TMS320F2812的三电平逆变器的研究

提出一种60°坐标的三电平中点箝位(Neutral Point Clamped,简称NPC)逆变器,仅需进行简单的坐标变换和计算就可得出参考电压矢量的作用区间以及输出电压矢量的作用时间,解决了传统空间矢量调制(SVPWM)方法需要大量三角运算以及扇区判断的缺点。采用首发矢量为正(负)小矢量的七段式调制技术的最优SVPWM算法,减小了开关损耗。根据负载电流方向和直流侧电容电压的大小,通过改变电压调整系数调整正负小矢量的作用时间来控制中点电位平衡。运用单片TMS320F2812对所提出的算法进行实验,结果验证了该方法的正确性和有效性。

Research on Three-level Inverter Based on TMS320F2812

A 60°coordinate system is proposed for the three-level neutral-point clamped(NPC) inverter,it requires only a simple coordinate trans-formation and arithmetic to determine the effetive sector of reference voltage vector and the effective time of the output voltage vectors can be also calculated.The disadvantages of traditional SVPWM algorithm are avoided.An optimal SVPWM algorithm based on 60° coordinate system is proposed,it makes use of seven-vectors modulation in which the positive or negative small vectors are used as the first output vector to reduce the switching loss.The voltage adjusting coefficient is changed to adjust the effective time of the positive and the negative small vectors,then the neutral point potential balance can be controlled,accroding to the direction of the load current and the capacitance voltage.The experiment is taken based on TMS320F2812.The results show the validity of the proposed algorithm,the conclusion of equivalency is verified,and the neutral-point voltage is in balance.