Improving Transient Performance of Reluctance Motors

Reluctance motors have a wide range of industrial applications. This is due to speed constancy and reliability in operation, as it is connected directly to the AC supply and operated at synchronous speed. Steady-state performance of this type of motors is extensively examined to get high output torque, improved power factor and extended stable region. Transient performance of reluctance motors has received relatively less attention. Previous emphasis was mainly on examining the effects of motor inertia, incorrect motor design parameters and number of pole slipping. A numerical technique has recently been applied to model damping and synchronizing torques of reluctance motors, and full analysis of dynamic performance is achieved [1]. This indicated that there are optimum values of electrical parameters which effectively give maximum damping to hunting oscillations and improve the dynamical performance. This leads to an extra attention being concentrated on how transient performance is affected by these electrical parameters which is the subject of this paper. The paper investigates the effects of all electrical parameters on transient performance and find out which parameters improve motor transients. Damping torque is modeled and the optimum values of electrical parameters, which give maximum damping to hunting oscillations, are given. The effects of these parameters on motor transients, following transient load increase and during starting conditions, are extensively studied. The study covers motor operation from either nominal or variable supply voltage and frequency.