Research On Rotor Position Self-sensing Control Of Permanent Magnet Synchronous Motor

Depending on the advance of power electronics , micro-electronics and motor manufacture technology, along with the development of the modern control theory, PMSM has been applied widely in numerous fields such as military field, industrial field and daily life for its prominent characteristics such as high-power density and high reliability. High-performance motor control requires rotor position to implement field-oriented control. This paper focuses on princples and practical technique of PMSM rotor position self-sensing control, probes deep into estimation algorithms based on novel sliding-mode observer and high-frequency voltage injection.Firstly, the mathematical model of PMSM and sliding mode variable structure control on which the PMSM current observer is set up is expounded.In order to improve estimation performance, the traditional sign function is replaced by a saturation function and estimated back electromotive force (EMF) is fed back to the current observer, at the same time, digital phase-locked loop(DPLL) is used to detect speed and then mathematical model and implementation plans of the system are established.Secondly, based on the system mathematical model, a simulation model in matlab/ simulink is established and the modeling designing processes of PMSM,current observer and DPLL are discussed in detail. Simulation results prove using the novel sliding mode ovserver to detect the rotor position is rational.Then, the initial rotor position self-detection based on high frequency injection is investigated. The mathematical model of high frequency injection for interior PMSM is analyzed, in addation, the scheme of salient pole position extraction and N/S pole judgement is established. Simulation results proves the validity of the theories and implementation plans.Finally, based on control-core, a high-performance digital signal processor named MC56F8346 manufactured by Freescale company, and power converter, an intellectualized power model named PM200DHA060 from Mitsubishi company,the hardware of PMSM digital speed control system is designed.The software of PMSM vector control system with roror position self-sensor based on the novel sliding mode observer is designed by modular thinking, and experiment results prove that the novel algorithm can improve estimation accuracy and expand estimated range and stability in low speed case.