PMSM Sensorless Vector Control Algorithm Research

Permanent magnet synchronous motor is small in size, high power factor, starting torque, Low noise low temperature rise, high power density,stable when operating; more diversified when putting into use and is gradually superseding the application of synchronous motor in medical equipment, national defense aerospace,domestic applianceFor precise control of permanent magnet motor we need to obtain the rotor position in real time. Traditional mechanical sensor makes system volume increases, the cost is high, thus sensorless control of permanent magnet synchronous motor technology become a hot research topic in the field of motor control. In addition, surface mounted permanent magnet synchronous motor is regarded as the research object in this paper to analyze and study motors on the basis of vector control strategy without position sensor.First of all, mounted on the permanent magnet synchronous motor rotor structure of mathematical modeling and the problem on complex three-phase static parameters, space coordinate transform, the motor mathematical model is converted into easy control of two phase rotating coordinate, simplifies the control method, based on the general application of vector control technology, make the motor to form double closed-loop system.this paper describes in detail the sliding mode observer method, provides an improving algorithm in light of the chattering problem resulting from the lag of switch of the switching surface in traditional sliding mode observer, and then combines phase-locked loop principle to make the result more stable and accurate.as for the stability problems resulting from the detection method under a full speed state, this paper adopts Popov hyper stability theory, which aims at the stability of the system on the basis of MRAS position detection, designs position observer based on MRAS, stability is verified by simulation.motor during the start-up and low speed phase back emf is hard to get this problem, combining with the characteristics of surface mounted motor rotor structure and high frequency pulse vibration signal injection method was proposed,using pulse vibration signal makes the motor with convex polarity, the output signal level convex modulation to obtain the rotor information, feasibility is verified by numerical simulation.