SELECTION OF AN APPROPRIATE NUMERICAL INTEGRATION METHOD FOR SOLVING THE OPTIMAL CONTROL PROBLEM OF AN INDUCTION MOTOR
Keywords:
Field-oriented control, induction motors, gradient based model predictive control, optimal rotor flux, energy efficiency, integrators.Abstract
The application of the gradient based model predictive control in an energy efficient control strategy of vector-controlled induction motor in transient behaviour when load conditions are changing is described in the current paper. A state-space approach is employed for the modelling a rotor-flux-oriented induction motor. The optimal control problem is defined as the minimization of the time integral of the energy losses with constraints. To this end the first-order optimality conditions are determined based on Portryagin’s Maximum Principle. The basic algorithm to solve the optimal control problem is introduced. The algorithmic options of model predictive control concerning the numerical integrations are discussed. It is shown that by appropriately choosing the numerical integration method the field-generating current optimal trajectory with the lower spikes can be obtained compared to the other embedded methods.
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