Comparative analyses and characterisation of average-value models of a brushless DC motor

Dynamic performance of a brushless DC motor is greatly influenced by a controller and the controller design relies on average-value models, which are vital in small signal and large signal analysis of electromechanical systems. Average-value model (AVM) of a brushless DC motor can be constructed by averaging motor variables or by exploring its resemblance to a DC motor. AVM can also be constructed by averaging motor currents in rotor reference frame because of its simplicity in analysis. In the present study, the appropriateness of average-value models in designing controllers for brushless DC motor were investigated by comparing the time domain parameters of the models and experimental results. Results indicated that the average-value model of the brushless DC motor derived from rotor reference frame model was highly appropriate for controller design.