Basic Research On Sensorless Control Technology Of Permanent Magnet Linear Synchronous Motor

Compared with other sophisticated systems, Permanent magnet linear synchronous motor (PMLSM) shows obvious advantage because of high thrust ability, low loss, fast response and ease maintenance. The sensorless control system of permanent magnet linear synchronous motor without sensor not only has a simple structure, high efficiency, excellent performance, and easy maintenance, but also has a small size, low cost, high reliability, and some special application. This paper resolves the key problems of sensorless PMLSM control system. A sensorless control system of PMLSM is established, the estimation algorithm, optimization and control as well as some key technologies of the PMLSM system are studied systematically by combining theoretical analysis, computer simulation with experiment. The main contents include the following sections.At first, the paper analyzes the structure and working principles of PMLSM. Based on the reference frames and transform criteria of PMLSM, mathematical models of PMLSM under three reference frames are given respectively.Second, the paper proposes the overall program of the sensorless PMLSM vector control based on sliding mode observer (SMO). The sensorless PMLSM vector control simulation system is built by the Matlab/Simulink software. Simulation results show that the controller has strong robustness and good immunity to disturbance performance.Next, the hardware and software for sensorless control system are built, and the specific circuits and flow charts are given. The composition and principle of the drive circuit, sampling circuit and protection circuit of intelligent power module (IPM), the fundamentals of the digital signal processor (DSP) and its peripheral circuits, the ways of sensorless estimation software using DSP are represented.Finally, controlling boards and software are debugged, and the control system is experimented on the PMLSM prototype. Experiments of speed and position estimation without sensor are done. The results show that experimental results agree with simulation results well, verify the availability of the theoretical study of control strategies and the simulation results, and further illustrate the feasibility of sensorless PMLSM control based on the SMO.