Researches On Performance Optimization Methods Of Inverter Compressor Permanent Magnet Synchronous Motor

Permanent magnetic synchronous motors(PMSMs)have been widely used in refergera-tion industry for its distinguished advantages of high efficiency,high power density and simple structure.Being the core of refrigeration equipment,its control characteristics mainly reflec-t on speed control precision,stability,speed range and energy efficiency ratio(EER).Where sensorless control optimization,parameter online identification,voltage source inverter(VSI)nonlinear voltage drop compensation and speed fluctuation suppression are the technical issues to be settled,the detailed will be illustrated in the following.Firstly,for sensorless control optimization of PMSM,sliding mode observer(SMO)bas-ing on L_qmodel is constructed in this paper,aiming at the back electromotive force(EMF)harmonics from VSI nonlinear voltage drop,magnetic saturation and space flux harmonics,Adaline network is employed to eliminate EMF harmonics based on the principle of adaptive cancelation.Where its weight gain is updated based on forgetting-factor recursive least square(FF-RLS)and then the convergence ratio can be confirmed.Elimination the 5th and 7th EMF harmonics of SMO based on Adaline,which can enhance rotor position estimation precision by normalized quadrature phase locked loop.Secondly,for parameter online identification of PMSM,this paper analyses the observabil-ity and coupling of PMSM based on nonlinear Lie derivative,due to general affine projection algorithm(APA)can not make a compromise between identification precision and efficiency,adaptive regularization APA(AR-APA)is adapted to parameter online identification.Aiming at the different variation characteristics of parameter,two time scale parameter identification modle is constrained,what’s more,adaptive proportional-integral(PI)decoupling controller is employed for demonstration experiments under load torque variation and speed up operating environment.Thirdly,aiming at the issues of current harmonics,rotor position estimation error and loss owing to VSI,a revised repetitive controller(RRC)is employed to VSI nonlinear voltage drop compensation.Owing to internal model deviation form phase delay discretization,the revised Savitzky-Golay(S-G)filter cascading delay item can approach any phase delay item in contin-uous domain,what’s more,revised S-G filter has larger noise reduction ratio(NRR)and cut-off frequency compared to the same order FIR filter.The proposed VSI nonlinear voltage drop com-pensation strategy is independent to current polarity,therefore,the compensation error owing to current clamp effect can be avoided.In the end,aiming at speed fluctuation of inverter compressor PMSM in low frequency range.Owing to the small sensitivity gain of general disturbance observer(DOB),the peri-odic disturbance suppression performance is comparably poor,periodic disturbance observer(PDOB)is employed to realize periodic load torque estimation and current feedforward com-pensation,and speed fluctuation can be reduced.In PDOB’s design procedure the control system sensitivity and robustness are considered.Aiming at different operation environments,the fun-damental item can be extracted by band pass filter and its frequency is estimated by adaptive notch filter basing on Steiglitz-Mc Bride(SM)method.