Patent ID: 8825440

Claim:
A resolver signal converter comprising: a first band-pass filter designed to pass, among frequency components of a first resolver signal which is a sine wave output from a resolver, a predetermined bandwidth of which the center frequency is the frequency of an excitation signal; a first sampling synchronous rectifier configured to sample the first resolver signal which has passed through the first band-pass filter, while synchronizing the first resolver signal with a reference signal which is based on the excitation signal, and to generate a detection angle signal sine value from the sampled first resolver signal; a second band-pass filter designed to pass, among frequency components of a second resolver signal which is a cosine wave output from the resolver, a predetermined bandwidth of which the center frequency is the frequency of the excitation signal; a second sampling synchronous rectifier configured to sample the second resolver signal which has passed through the second band-pass filter, while synchronizing the second resolver signal with the reference signal, and to generate a detection angle signal cosine value from the sampled second resolver signal; and an angle calculator configured to calculate a detection angle from the detection angle signal sine value and the detection angle signal cosine value, wherein each of the first and second sampling synchronous rectifiers is configured to: sample the respective first or second resolver signal at a timing when the positive amplitude of the reference signal becomes maximum and at a timing when the negative, amplitude of the reference signal becomes maximum; either store the sampled resolver signal as it is in a case where the resolver Signal is sampled at the timing when the positive amplitude of the reference signal becomes maximum, and store the sampled resolver signal after inverting the sign of the resolver signal from minus to plus in a case where the resolver signal is sampled at the timing when the negative amplitude of the reference signal becomes maximum, or store the sampled resolver signal as it is in a case where the resolver signal is sampled at the timing when the negative amplitude of the reference signal becomes maximum, and store the sampled resolver signal after inverting the sign, of the resolver signal from plus to minus in a case where the resolver signal is sampled at the timing when the positive amplitude of the reference signal becomes maximum; and arrange the stored resolver signals in chronological order to generate the respective detection angle signal sine value and detection angle Signal cosine value.