WHEEL DIAMETER MEASURING INSTRUMENT FOR ELECTRIC VEHICLE

摘要

A wheel diameter measuring instrument for measuring wheel diameters of an electric vehicle employing the velocity sensorless vector control by application of a synchronous motor. A wheel diameter measuring instrument for an electric vehicle equipped with a synchronous motor driven by a power converter which converts the direct-current voltage into the alternating-current voltage includes a voltage detector for detecting the alternating-current voltage arising due to magnetic field of the synchronous motor during coasting of the electric vehicle while the power converter stops its operation and an arithmetic operation section for computing diameters of wheels driven by the synchronous motor in accordance with the velocity information of the electric vehicle and the alternating-current voltage detected by the voltage detector.