Average-value model of the brushless D 120 degrees inverter system

An average-value model of a 120 degrees brushless DC motor is developed by transforming the stator variables to the rotor reference frame and expressing the average applied voltages in this reference frame over a switching interval of the inverter. The performance as predicted by the average-value model is shown to be accurate for normal operation by comparison with the performance calculated using a detailed model. The average-value model becomes less accurate when the phase-shift angle is varied markedly from normal. This model should be very useful to the control system analyst and as an educational tool, since it allows a straightforward comparison with the equations which describe the 180 degrees brushless DC motor.<
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