Patent ID: 6680593
Filing Date: 2004-01-20
Classification: G11B,H02P

Abstract:
A motor comprising:a rotor having a field part which generates field fluxes; Q-phase windings (Q is an integer of 3 or more); voltage supplying means, including two output terminals, for supplying a DC voltage; power supplying means having Q first power transistors and Q second power transistors, each of said Q first power transistors forming a current path between a first output terminal side of said voltage supplying means and one of said Q-phase windings, and each of said Q second power transistors forming a current path between a second output terminal side of said voltage supplying means and one of said Q-phase windings; voltage detecting means for producing a detected pulse signal which responds to terminal voltages of said Q-phase windings; phase detecting means for producing a phase pulse signal which responds to terminal voltages of said Q-phase windings; state shifting means for shifting a holding state from one state to at least one other state in sequence responding to said detected pulse signal of said voltage detecting means; activation control means for controlling active periods of said Q first power transistors and said Q second power transistors responding to said holding state of said state shifting means; commanding means for producing a command signal which responds to said phase pulse signal of said phase detecting means; and switching operation means for causing at least one power transistor among said Q first power transistors and said Q second power transistors to perform high-frequency switching responding to said command signal; wherein said activation control means causes each of said active periods of said Q first power transistors and said Q second power transistors to become larger than the period of 360/Q electrical degrees, said switching operation means produces a high-frequency switching pulse signal which responds to said command signal and switches said at least one power transistor responding to said switching pulse signal, and said phase detecting means includes: slant producing means for producing a slant voltage signal at a terminal of n capacitor, said slant voltage signal responding intermittently to a voltage difference between one of the power supplying terminal voltages and the common terminal voltage of said Q-phase windings during sampling periods and having a voltage slant during at least one rest period except said sampling periods, and phase pulse producing means for producing said phase pulse signal by comparing said slant voltage signal to a reference voltage.