Patent ID: 8084975

Claim:
A brushless motor control system that drives a brushless motor used as a starter motor of an engine, the motor control system detecting a rotor stop position when activating the brushless motor which includes a stator having coils of three phases U, V, and W, and controlling a phase voltage for energizing the coils of the respective phases U, V, and W, wherein the brushless motor includes the stator having coils of phases U, V, and W of N (N≧2) poles, in which any one phase coil among the coils of the phases U, V, and W is removed in one of the N poles, and wherein the brushless motor control system comprises: a current rise detecting circuit that, when the brushless motor is in a stop state, sequentially selects coils of two phases from the coils of the respective phases U, V, and W, applies a predetermined direct current voltage between the selected coils of the two phases, and detects a value of an electric current flowing to the selected coils of the two phases; and a rotor stop position detecting unit that determines a rotor stop position of the brushless motor based on information of the value of the electric current flowing to the respective phase coils which is detected by the current rise detecting circuit.