Research On Position Observation Of Permanent Magnet Synchronous Motor At Full Speed Range

In recent years,the interior permanent magnet synchronous motor(IPMSM)has been widely used for its advantages in power density and efficiency.In view of the cost,reliability,and environmental adaptability problems brought about by position sensors,the position observation and position sensorless control of permanent magnet synchronous motors have become a hot spot in recent years.In order to realize the effective observation of the position in the full speed range including the static start state,according to the IPMSM structure and electrical characteristics,the injection method is mostly used in the stationary and low speed stages,and the fundamental wave model method is used to observe the rotor position in the medium and high speed stage.Looking at the current research status,it is not difficult to find: in the zero-low speed stage,the rotating high frequency injection method has good stability,but it has the problem of low accuracy due to demodulation delay;observation in the transition area from zero low speed to medium and high speed The plan needs to be optimized,and the observation accuracy needs to be improved.In view of this,this paper has conducted an in-depth study on the rotating high frequency injection method and the composite position observation scheme in the transition area,and on this basis,discussed the position observation scheme of the permanent magnet synchronous motor in the full speed range.1.For the problem that the position estimation accuracy of the rotating high frequency injection method is affected by the control delay and the filter delay,the rotating high frequency injection method based on positive sequence component compensation is studied:(1)Reveals the deficiency of demodulation algorithm of static coordinate system based on positive and negative sequence high frequency current separation affected by motor speed.(2)A demodulation algorithm of rotating coordinate system based on positive and negative sequence high frequency current separation is proposed to overcome the influence of speed and improve the compensation and observation accuracy.(3)In order to avoid the complex filtering operation required for the separation of positive and negative sequence high frequency currents,a rotating reference frame demodulation algorithm based on high frequency current cross multiplication is further proposed,which simplifies the signal processing process and improves the operation efficiency.2.For the problem of observing the location of the transition area between zero low speed and medium high speed,the composite observation scheme based on the rotating high frequency injection method and the fundamental wave sliding mode observer method was studied:(1)Two observation schemes are needed for the transition area Between two phase-locked loop schemes and a single phase-locked loop scheme,and concluded that a single phase-locked loop has obvious advantages.(2)The accuracy of the two observation schemes by quantitative analysis of high-frequency injection volume The impact of the transition zone optimization composite observation scheme is proposed,which not only shortens the high frequency voltage range,but also improves the position observation accuracy of the transition zone.3.Taking a permanent magnet synchronous motor for commercial electric vehicle as the object,the analysis and design of this paper are comprehensively verified through simulation and experiment.