基于Sigma-Delta调制的逆变器死区谐波抑制研究

Research on harmonic suppression of inverter dead time based on sigma-delta modulation

空间矢量调制(SVPWM)的载波信号在电压、电流频谱中产生突出的谐波,进而产生难以解决的电磁噪声,所以有学者提出了基于Sigma-Delta的调制策略。Sigma-Delta调制(SDM)由于其自身的特点,又被称为脉冲密度调制(Pulse Density Modulation)。它能够有效减少SVPWM中恒定载频引起的尖峰噪声信号。但是传统应用在三相逆变中的脉冲密度调制由于DAC采样位置的原因,使死区引起的谐波不能受到抑制。改进脉冲密度调制反馈环的位置且省去传统DAC环节,通过仿真验证对死区引起的谐波抑制效果。仿真结果显示,提出的改进方案能够有效抑制传统脉冲密度调制方案中由死区引起的5次、7次谐波。

The carrier signal of space vector modulation(SVPWM)generates prominent harmonics in the voltage and current spectrum,and then generates difficult electromagnetic noise.Therefore,some scholars have proposed modulation strategies based on Sigma-Delta.Due to the characteristics of Sigma-Delta modulation(SDM),this modulation method is also called pulse density modulation.It can effectively reduce the spike noise signal caused by constant carrier frequency in SVPWM.However,the pulse density modulation traditionally used in three-phase inverters cannot suppress the harmonics caused by the dead band due to the DAC sampling position.Improve the position of the pulse density modulation feedback loop and omit the traditional DAC link,and verify the harmonic suppression effect caused by the dead zone through simulation.Simulation results show that the proposed improved scheme can effectively suppress the 5 th and 7 th harmonics caused by the dead zone in the traditional pulse density modulation scheme.