Patent ID: 6249095
Filing Date: 2001-06-19
Classification: H02P

Abstract:
A polyphase motor driving system comprising:a polyphase motor having a rotor provided with a rotary shaft and a plurality of permanent magnets connected to a circumference of the rotary shaft; andan annular stator surrounding the rotor and rotatably holding the rotor, said stator having n phases and n.times.m magnetic poles, where n is an integer not less than 3 and m is an integer not less than 1, a coil having a first end connected to a common terminal and wound around each of n pairs of adjacent ones of the magnetic poles so that one of each pair of the magnetic poles serves as a first polarity and the other one of each pair of the magnetic poles serves as a second polarity different from the first polarity, wherein a magnetic field to rotate the rotor is generated by applying a voltage having the phases between the common terminal and a second end of the coil of each of the pairs;means for receiving a pulse signal from a position detector which is connected to the rotary shaft of the rotor of the polyphase motor and which generates the pulse signal every time the rotor rotates by an electric angle of 360.degree./n, where n is a positive integer; andmeans for judging a present position of the rotor every time one pulse of the pulse signal is received, and for supplying a polyphase current to the polyphase motor at a timing based on the judgment, thereby switching an excitation phase of the polyphase motor and rotating the rotor.