Patent ID: 8541964

Claim:
A brushless motor rotation-position detection system comprising: a resolver mounted in a brushless motor; a motor controller for driving the brushless motor; and a microcomputer comprising calculation means that performs calculation for controlling the motor, based on rotation-position information on the brushless motor, wherein the calculation means includes: an excitation signal supply means that supplies an excitation signal to the resolver; an analogue/digital converter that alternately applies analogue/digital conversion to a sine wave signal and a cosine wave signal outputted from the resolver after an excitation signal is supplied to the resolver; a resolver amplitude calculation means that calculates a sine wave amplitude and a cosine wave amplitude, based on the sine wave signal and the cosine wave signal obtained through the analogue/digital conversion by the analogue/digital converter; and a motor angle calculation means that calculates a motor rotation angle of the brushless motor, based on the sine wave amplitude and the cosine wave amplitude calculated by the resolver amplitude calculation means, wherein the analogue/digital converter determines whether to convert the sine wave signal or the cosine wave signal based on a counter value stored in the microcomputer.