基于扰动观测器的永磁同步电机电流解耦及谐波抑制方法

Current Harmonic Suppression Method of Permanent Magnet Synchronous Motor Based on Disturbance Observer

在永磁同步电机电流环PI调节的矢量控制系统中,u_(dref)和u_(qref)尚不能真正实现对d-q轴电流的解耦控制,且由于逆变器的非线性和电机参数的时变性,使得相电流通常存在多种干扰,其表征为电流的谐波。首先建立了永磁同步电机在逆变器的非线性和电机参数的时变性下的实际模型;其次,分析了逆变器非线性及参数时变性的具体扰动模型;最后,提出一种扰动观测器,根据电机d-q轴电压方程,观测耦合项和扰动项,并对其补偿,以实现电流解耦及谐波抑制。通过对提出的扰动观测器的分析,说明了该方法电流解耦及谐波抑制机理,同时也给出了观测器的参数选取和稳定性证明。结果表明加入扰动观测器,实现了d-q轴电流的解耦,并使得A相电流的THD减小了16%,5次和7次谐波分别减小了26%和17%,验证了所提扰动观测器的电流解耦及谐波抑制效果。

In the vector control system of permanent magnet synchronous motor current loop PI regulation,u_(dref) and u_(qref) can not really realize the decoupling control of d-q axis current.Due to the nonlinearity of inverter and the time-varying of motor parameters,there are usually many kinds of disturbances in phase current,which are characterized by current harmonics.Firstly,the practical model of permanent magnet synchronous motor was established under the nonlinearity of inverter and the time-varying of motor parameters.Secondly,the specific disturbance model of inverter nonlinearity and time-varying parameters was analyzed.Finally,a disturbance observer was proposed.According to the d-q axis voltage equation of the motor,the voltage disturbance term and coupling term were observed and compensated to suppress all kinds of current harmonics.By analyzing the proposed disturbance observer,the current decoupling and harmonic suppression mechanism of this method were explained,and also the parameter selection and stability proof of the observer were given.The results show that by adding the disturbance observer,the decoupling of d-q axis current is realized,and the THD of phase A current is reduced by 16%,and the 5th and 7th harmonics are reduced by 26%and 17%respectively.The current decoupling and harmonic suppression effect of the proposed disturbance observer is verified.