基于TMS320F28377D的混合脉宽调制策略研究

Research on Hybrid Pulse Width Modulation Strategy Based on TMS320F28377D

牵引逆变器受开关频率的限制,电机电流含有丰富的谐波。电流谐波会引起电机发热严重,系统损耗大,同时还会导致电机转矩脉动,影响电机控制性能。为实现全速范围内逆变器输出脉冲电压的对称性,减小低次谐波对系统的影响,在此通过对特定次谐波消除脉宽调制(SHEPWM)原理的深入分析,提出了一种基于TMS320F28377D的混合脉宽调制(PWM)方法,实现了各调制方式的平滑切换。该方法可以满足控制算法和调制策略在一个CPU的两个核中独立运行,提高了程序运行的可靠性和高效性,可有效降低低次谐波,提高系统效率,简化了数字实现,具有一定的工程意义,仿真和实验结果表明了所提混合PWM策略及其切换方法的可行性和有效性。

The traction inverter is limited by the switching frequency,and the motor current contains rich harmonics.Current harmonics can cause serious motor heating,large system losses,and can also cause motor torque ripple,affecting motor control performance.In order to achieve the symmetry of the output pulse voltage of the inverter in the full speed range and reduce the impact of low-order harmonics on the system,the principle of selective harmonic elimination pulse width modulation(SHEPWM)is analyzed through in-depth analysis of specific harmonics.A hybrid pulse width modulation(PWM)method based on TMS320F28377 D is proposed,which realizes the smooth switching of each modulation mode.This method can satisfy the control algorithm and modulation mode running independently in two cores of a CPU,which improves the reliability and high efficiency,can effectively reduce low-order harmonics,improve system efficiency,simplify digital implementation.It has certain engineering significance.The simulation and experimental results show the feasibility and effectiveness of the hybrid PWM strategy and switching method proposed.