Method and apparatus for detecting abnormality in rotation sensor

An apparatus for detecting an abnormality in a resolver which generates a signal in accordance with an angle of a rotor, comprising:

• a first R/D converter for outputting a rotation signal on the basis of an output signal of the resolver;
• a second R/D converter which is connected to the first R/D converter in parallel and outputs an electrical angle signal on the basis of an output signal of the resolver;
• and
• a unit for diagnosing whether there is an abnormality in the resolver or not from the relation between the rotation signal of the first R/D converter and the electrical angle signal of the second R/D converter.

A method of detecting an abnormality in a resolver which generates a signal in accordance with an angle of a rotor, comprising the steps of:

• supplying a reference signal having a predetermined periodic waveform to a resolver attached to a rotor;
• allowing the resolver to generate a sin signal having a waveform obtained by amplitude-modulating the reference signal by sin θ and a cos signal having a waveform obtained by amplitude-modulating the reference signal by cos θ when the angle of the rotor is θ;
• detecting the angle θ on the basis of the sin signal and the cos signal;
• outputting a rotation pulse signal and a reference position signal on the basis of the angle θ;
• and
• detecting the presence or absence of an abnormality in the signal processing unit for angle detection on the basis of the angle θ detected by the signal processing unit for angle detection and the angle θ′ calculated from the rotation pulse signal and the reference position signal of the signal processing unit for angle detection.