Self-controlled polyphase synchronous motor drive system

摘要

A self-controlled polyphase synchronous motor drive system having means for producing rotor digital timing signals representative of the position of the rotor relative to the stator, means for producing pulse width modulation control signals wherein the pulse width thereof is responsive to a motor power factor command signal, a plurality of phase control means equal in number to the number of phases of the polyphase stator and responsive to the variable pulse width modulation control signals and including means for producing a modulated analog reference signal from one of two selected stator voltages and means for summing the amplitude modulated analog reference signal with an unmodulated analog reference signal produced from the other of the two selected stator voltages and for comparing the sum thereof with a threshold voltage signal to produce as an output therefrom two motor voltage derived digital timing signals for each phase of the polyphase stator in response to the speed of the motor such that an absence of voltage digital timing signals occurs at zero motor speed and voltage digital timing signals having distortion is produced at low motor speeds and digital gating command signal generating means responsive to the voltage digital timing signals from each of the phase control means and to the rotor digital timing signals for producing digital gating command signals having a leading edge determined by one of the voltage digital timing signals or that of a selected one of the rotor digital timing signals and the width of which is equal to 360 degrees divided by the number of phases of the polyphase stator is shown.PPA commutation margin detecting circuit and rotor position sensing circuit are also shown.