Reference signal generation circuit, angle converter, and angle detection apparatus

Abstract

A reference signal generation circuit generates a reference signal used in synchronous detection for removing an excitation signal component in an angle calculation section that converts a detection angle θ obtained from two-phase resolver detection signals output from a resolver, to a digital output angle φ. The reference signal generation circuit includes a first multiplier, a second multiplier, and an adder. The first multiplier multiplies one of the resolver detection signals sin θ sin(ωt+Δω) by the sine value sin φ of the digital output angle φ obtained from the angle calculation section. The second multiplier multiplies the other resolver detection signal cos θ sin(ωt+Δω) by the cosine value cos φ of the digital output angle φ obtained from the angle calculation section. The adder adds the output of the first multiplier and the output of the second multiplier to output the sum signal sin(ωt+Δω) as the reference signal.