Research On Low-cost Rotor Position Detection And Sensorless Control For SPMSM

Permanent magnet synchronous motor(PMSM)is used widely because of its good performance and simple structure.Precise rotor position information is necessary for close-loop control,and switch-type hall position is used to cut cost and improve stability.This sensor is low-resolution,so linearity of output signals is unavoidable.Besides,sensorless control is a good choice.But SPMSM does not have saliency,so it is difficult to do sensorless control when motor speed is low.This thesis presents research of processing switch-type hall position signals to get rotor position information and surface-mounted PMSM sensorless control strategies.Firstly,power electronics topology is introduced.Then there is hall position sensor installation position automatic identification method to get hall shift angle.And simulation and experiment are applied to prove zero-order and first-order algorithms.To make better result,observer is used and rated winding current THD reduces from 2.73% to 1.61%.After doing analysis about start-up performance of three algorithms,square-wave driving is using to get bigger torque.Then fluctuating high frequency voltage injection is used to get rotor position information and PLL is replaced by robust observer for better performance when sensorless control is applied.Observer coefficients are calculated and the algorithm is proved by simulation and experiment.The result shows that convergence time reduces form 0.5s to 10 ms.Finally,slidingmode observer is applied for high speed PMSM sensorless control.The same thing is done to prove this method.