Method and apparatus for dynamic range optimization in a PWM motor drive

摘要

A system for increasing the power delivered to a brushless dc or induction motor from a sinusoidal motor drive by maximizing the dynamic range available to the motor winding excitation signals. According to one embodiment of the invention, sinusoidal excitation currents are applied to all but one of the primary windings of a brushless dc or induction motor. A variable voltage drive is applied to the one remaining winding. The voltage drive maximizes the dynamic range available to the sinusoidal excitation currents by selecting the voltage applied to that one remaining winding to be the difference between one half the dc source voltage and the instantaneous average of the highest and lowest of the motor terminal voltages.