BRUSHLESS MOTOR DRIVING CIRCUIT

• Main Author: NAITO, HAYATO
• Format: Patent
• Language: English; Korean
• Published: 07.04.1994
• Edition: 5
• Subjects: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORSOR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION

The coil middle point voltage of a brushless motor drive circuit is kept to a proper level and, therefore, brings forth stable and improved torque ripple correction effects even when the electric current gain of the source side and that of the sink side of the drive coils of the circuit are not well balanced. Such a brushless motor drive circuit comprises a position detecting element for detecting the rotary position of the rotor relative to the stator, a signal synthesizing circuit for synthesizing an m-phase soft switching signal out of the output of said position detecting element, a plurality of groups of transistors for switching the electric current supplied to said m-phase drive coils, a current control circuit for controlling the rate of electric current supplied to the m-phase drive coils by controlling the plurality of groups of transistors, a rate of electric current detecting resistor for detecting the drive coil current so as to negatively feed it back to said current control circuit, a circuit for supplying a reactive current to the rate of electric current detecting means during a period when the m-phase drive coils are not to be energized, an interrupting circuit for interrupting the reactive current during a period when m-phase drive coils are to be energized, a coil middle point detecting circuit for detecting the voltage applied to the middle points of the m-phase drive coils and a coil middle point feedback circuit for feeding back changes in the output of the coil middle point detecting circuit to the plurality of groups of transistors.