| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect rotation angle of a rotor without increasing the number of ground wirings. SOLUTION: In the rotation angle detection devices 22, 50, an AC exciting voltage is applied to one end of an exciting coil 28, and a common ground line 46 is connected with the other end of the coil 28. In output coils 30, 32, output voltages are led out from one ends, and the common ground line 46 is connected with the other ends. The output voltage is a voltage wherein an AC rotation angle voltage whose amplitude is increased and decreased depending on the rotation angle of a rotor 24 is superposed with an AC bias voltage caused by ground line impedance 48 and an exciting current. An ECU 50 stores data necessary for calculating the AC bias voltage on the basis of a relation with passing time from a reference timing. An AC bias voltage at the point when a time passes from the reference timing as far as detection of the output voltages is subtracted from the output voltages of the output coils 30, 32. The AC bias voltage is calculated from the stored data. COPYRIGHT: (C)2004,JPO
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