Hitachi Automotive Systems, Ltd.

Hitachi Astemo Ltd.

Hiroyuki Mamada

Shingo Ooba

Kazuhiko Arai

A rotational angle determining device periodically samples a resolver signal output from a resolver receiving an alternating current excitation signal, the sampling being performed at a timing at which the excitation signal reaches a peak or trough value, based on a timer signal to which initial phase alignment is performed with respect to the excitation signal, and then the device performs A/D conversion of a voltage value of the sampled resolver signal, to determine the rotational angle of the rotor of the resolver. The excitation signal is periodically sampled at a predetermined timing based on the timer signal, and a presence or absence of a phase shift between the excitation and timer signals is detected based on a change in A/D converted value AD1n (n=1, 2, . . . ) obtained by A/D conversion of a voltage value of the sampled excitation signal.

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Isesaki, Japan

Hiroyuki Mamada