초록 ▼

The speed of a rotor in a two-winding, permanent magnet motor can be accurately controlled with a dual-polarity pulse width modulation drive signal. The phase back emf signal generated in the non-excited winding is compared against the phase of a command signal and the results of the comparison are

The speed of a rotor in a two-winding, permanent magnet motor can be accurately controlled with a dual-polarity pulse width modulation drive signal. The phase back emf signal generated in the non-excited winding is compared against the phase of a command signal and the results of the comparison are used to vary the duty cycle of the drive signal.

대표청구항 ▼

[ What is claimed is:] [1.] An apparatus for driving a two winding permanent magnet motor in response to a command signal, comprising:means for generating an alternating-polarity, variable duty-cycle, pulse width modulated drive signal for one of the windings,means for sensing the back-emf generated

[ What is claimed is:] [1.] An apparatus for driving a two winding permanent magnet motor in response to a command signal, comprising:means for generating an alternating-polarity, variable duty-cycle, pulse width modulated drive signal for one of the windings,means for sensing the back-emf generated in the other of the windings, andmeans, responsive to the command signal and the means for sensing the back-emf, for varying the duty cycle of the drive signal, said means for varying the duty cycle comprisingmeans for comparing the relative phases of the command signal and the back-emf signal,means for generating an amplitude-modulated, suppressed-carrier, square-wave signal in phase with the back-emf signal, where the amplitude modulation is proportional to the relative phase difference between the command signal and the back-emf signal; andmeans for converting the amplitude-modulated, suppressed-carrier, square-wave signal to alternating positive and negative pulses, where the width of each pulse is proportional to the amplitude of the corresponding phase of the square-wave signal, and the positive and negative pulses are in phase with the amplitude-modulated, suppressed-carrier, square-wave signal.