基于数字信号处理器实现特定消谐脉宽调制控制技术的研究

在大功率交流传动控制中,传统的PWM(脉宽调制)方法输出由于存在低次谐波,会使电流和转矩产生脉动,影响控制精度。以三相电压型逆变器为分析对象,提出了一种基于数字信号处理器(DSP)来实现特定次谐波消除脉宽调制(SHEPWM)控制技术。该技术是首先根据SHEPWM控制技术的基本原理建立其特定谐波消除中开关角与调制度之间的数学模型;然后通过Matlab软件对该非线性数学模型方程组进行求解,得到对应的PWM单相电压脉冲的输出波形;同时利用dsPACE半实物仿真平台对SHEPWM控制技术进行数字化实现及验证;最后通过试验平台分析验证其输出电压、电流在不同载波比下的谐波消除情况。结果表明:基于DSP实现的SHEPWM控制技术,在实际应用中能够消除低次谐波、减小电流和转矩脉动,并能提高电能控制质量。

Selected Harmonic Elimination PWM Control Technology Realized Based on DSP

In high-power AC drive control,the output of conventional PWM(pulse width modulation)method has low-order harmonics,which will cause current and torque ripple and affect the control accuracy. Taking three-phase voltage inverter as the research object,a control technology to achieve the selected harmonic elimination pulse width modulation(SHEPWM)based on digital signal processing(DSP)is proposed. Firstly,according to the basic principle of SHEPWM control technology,the mathematical model between switching angle and modulation degree in selected harmonic elimination is established;then the non-linear mathematical model equation group is solved by Matlab software, obtaining the output waveform of single-phase voltage pulse of corresponding PWM;at the same time,the SHEPWM control technology is digitalized and verified by using dsPACE semi-physical simulation platform;finally,the harmonic elimination situation of output voltage and current wave of SHEPWM under different carrier ratios is analyzed through testing platform. The results show that the SHEPWM control technology based on DSP can eliminate low-order harmonics,reduce current and torque ripple and improve the quality of power control in practical application.