Sliding mode control of interior permanent magnet synchronous motors

The paper presents a digital control system of speed for an interior permanent magnet synchronous motor (IPMSM), based on the sliding mode control of the electromagnetic torque. The torque controller was designed taking into consideration a model of the machine in the rotating reference frame attached to the stator flux. The feedback signals are determined by using the measured values of currents and voltages in the fixed two-phase system. The reference for the reactive torque is deduced from the orthogonal system attached to the rotor. The reactive and electromagnetic torques are controlled by nonlinear hysteresis controllers; their output signals are used for generating the control signals of the inverter, based on switching tables. The angular velocity controller is linear, of I+PI type. Real time simulations of the control system in C++ confirm the proposed solution.