三相两电平逆变器死区效应谐波分析及其补偿方法研究  

Harmonic Analysis and Compensation Method for Dead-time Effects in Three-phase Two-level Inverters

作　　者：焦宁 刘天琪[1] 王顺亮[1] 李媛[1] JIAO Ning;LIU Tianqi;WANG Shunliang;LI Yuan(School of Electrical Engineering and Information,Sichuan University,Chengdu 610065,Sichuan Province,China)

机构地区：[1]四川大学电气信息学院,四川省成都市610065

出　　处：《电网技术》2020年第6期2169-2176,共8页Power System Technology

基　　金：国家自然科学基金资助(51707126)。

摘　　要：电压源换流器在高压直流输电及新能源并网中起着至关重要的作用。为研究基于脉冲宽度调制技术(pulsewidth modulation,PWM)三相逆变器受死区影响的谐波特性,首先,基于傅里叶级数分析的方法,推导出谐波的定量计算公式。通过PWM的调制过程详细分析了死区时间对三相逆变器输出相电压波形的影响。在此基础上推导出了附加死区的谐波计算公式,定量分析了死区对谐波幅值的影响,从理论上揭示了死区效应的谐波产生机理。其次,基于所推导的谐波定量计算公式,从谐波含量理论计算的角度,提出一种在调制信号中注入补偿分量的死区效应补偿方法。最后,仿真和实验结果证明该谐波计算方法可以定量分析死区效应的影响,并验证了所提出的补偿算法能够有效补偿死区效应,验证了此定量分析的正确性和补偿方法的有效性。Voltage source converter plays an important role in the high voltage direct current transmission and new energy grid-connected power system.To study the harmonic characteristics of three-phase inverters with sinusoidal pulse width modulation(SPWM),the calculation formula based on Fourier series is deduced for quantitative evaluation harmonics.The impact of dead-time on the output phase voltage waveform of the inverter is analyzed in detail through the modulation process.Then,the influence of dead-time on harmonic amplitude is analyzed quantitatively.The harmonic expressions affected by dead-time are deduced to reveal the mechanisms of harmonics generation from dead-time effects.A compensation method by injecting offset voltage in the modulation signal is proposed,and the compensation component is obtained by the derived harmonic quantitative calculation formula.Finally,the simulation and experimental results verify the correctness of the harmonics quantitative calculation for dead-time effects,and the compensation algorithm can effectively reduce total harmonic distortion of the phase current.The validity of this quantitative analysis and the effectiveness of the compensation method is verified.

关 键 词：正弦脉宽调制 PWM逆变器 谐波 死区效应 死区补偿 

分 类 号：TM721[电气工程—电力系统及自动化]