Simulation of current control for a permanent magnet spherical stepper motor

In order to control the permanent magnet spherical stepper motor effectively and to alleviate the steady-state errors, programmable current sources were applied to control the magnitude of the currents in the stator coils instead of controlling the motor with relays. The dynamic model of the rotor expressed with Cardan angle rotation was set up in rotor-fixed coordinates frame. Current control strategy was designed to drive the rotor tracldng point-to-point motion or continuous path motion. Simulation results show high performance of the new control laws.