초록 ▼

A motor drive circuit for a three-phase motor includes a commutator that provides a driving voltage to the motor from a DC voltage source. A sequencer operates the commutator to pulse width modulate the source voltage so that the driving current has a continuously variable waveform, such as a sinuso

A motor drive circuit for a three-phase motor includes a commutator that provides a driving voltage to the motor from a DC voltage source. A sequencer operates the commutator to pulse width modulate the source voltage so that the driving current has a continuously variable waveform, such as a sinusoidal waveform. The sequencer is responsive to an error signal from a phase detector to align the driving voltage waveform with a motor current waveform. The phase detector includes a sensor that senses the motor current and provides a voltage input to first and second sample circuits. The first sample circuit provides a plurality of samples of respective instantaneous values of the sensed voltage, and the second sample circuit provides a sample of a selected instantaneous value of the sensed voltage. An error generation circuit provides an error signal based on a difference between the second sample and each of the plurality of first samples.

대표청구항 ▼

[ What is claimed is:] [1.]1. A motor drive circuit for a three-phase motor, the motor drive circuit including a commutator arranged to provide a driving voltage to the motor from a DC voltage source, a sequencer operating the commutator to pulse width modulate the source voltage so that a motor cur

[ What is claimed is:] [1.]1. A motor drive circuit for a three-phase motor, the motor drive circuit including a commutator arranged to provide a driving voltage to the motor from a DC voltage source, a sequencer operating the commutator to pulse width modulate the source voltage so that a motor current has a continuously variable waveform, the sequencer being responsive to an error signal to align the driving voltage with the motor current waveform, and a phase detector supplying the error signal to the sequencer comprising:a sensor providing a sense voltage representative of the motor current;a first sample circuit providing a plurality of first samples of respective instantaneous values of the sense voltage;a second sample circuit providing a second sample of a selected instantaneous value of the sense voltage; andan error generation circuit providing the error signal based on a difference between the second sample and each of the plurality of first samples.