Sliding Mode Speed Control of Permanent Magnet Synchronous Machines

In this paper sliding mode speed control techniques of a permanent magnet synchronous machine are presented. The closed loop control structure is achieved with a cascade controller structure, where the field-oriented control's current controllers are chosen to be PI type controllers. During modelling and controller analysis the sliding mode controllers chattering behavior is analyzed in two different control approaches. In the first approach the basic switching function was replaced with a sigmoid function, and the control rule was also augmented with equivalent control that acts as a feedforward controller. The second approach is based on a variable exponential reaching rule. The current reference generation is done by a Maximum-Torque-per-Ampere method, where the reference current trajectory was obtained using the finite element calculated, saturating inductances.