Research On The Control Strategy Of PMSM Based On Low Resolution Sensors

High-resolution rotor position information which can be obtained by usingmechanical sensors is needed in high-performance PMSM control technology. However,mechanical sensors increases system cost, tends to reduce the system reliability and limitswidely application of PMSM. Sensorless approaches can largely reduce the cost of system,but they are generally complex, stricter with parameters and limited to the speed range. Asa result, low-resolution position sensor technology becomes one of the research focuses.In this thesis low-resolution position sensor control technologies of PMSM have beenresearched. It presents the coordinates transformation and the mathematical models inthree coordinates of PMSM. After analyzing the space vector pulse width modulation(SVPWM) and its implementation, a simulation model of PMSM is established.Low-resolution position estimations based on three locked hall sensors are researched indetail and one improved algorithm is proposed to reduce the starting estimation error.Methods mentioned above are realized in PMSM simulation model. A new control methodbased on Model Reference Adaptive System (MRAS) is proposed by combining MRASobserver and low-resolution hall sensor signals. It has the advantages of both and can gethigh-resolution position estimation in each hall sector which can reduce the cumulativeerror of MRAS observer. It is also insensitive to the change of parameter. The simulationresults demonstrate that the method performances good and works well.