Sliding Mode Control of PMSM Based on Load Observer

In order to realize speed tracking of Permanent Magnet Synchronous Motor with uncertain load, the Sliding Mode Control is applied to design tracking controller. When load changes, the speed of the closed-loop control system, which is designed according to conventional Sliding Mode Control, is different from the set speed, and the out-put of the speed tracking controller has strong chattering phenomenon. In order to minimize or eliminate the chattering phenomenon, the load observer is imported to the Sliding Mode Controller as control input signal of beforehand compensation, so that the system is provided excellent disturbance-rejection and chattering-free performance. To improve the dynamic response capability of the system, a variable switch gain SMC is designed in this paper. It has faster response speed and chattering-reduction ability. In this paper, the systems with and without load observer participated in control are compared by simulation. The effectiveness and validity of the paper are approved by the theory analysis and simulation results.