Second-order sliding mode control based on super-twisting algorithm for the speed outer loop of motors

Aiming at the speed outer close-loop control for the motors, the design method of the second-order sliding mode control law based on the Super-Twisting algorithm(STA) is researched, which doesn't need the derivative or the extreme value of the speed. The stability is proved by using Lyapunov function. And the influence for the system stability and the rapidity of convergence by the proportional of the sliding mode variable is analyzed, also the commonality and the differences of the various types proportional of the sliding mode variable. Simulation results show that the introduced proportional of the sliding mode variable in STA can improve the convergence speed of the system regardless of the running state of the motor, and the STA second-order sliding mode features of the motor system is not changed. Due to the unified rotor motion equation, the analyzed result of this paper is general to the speed loop second-order sliding mode control for all kinds of motors.