Hitachi Automotive Systems, Ltd.

Hitachi Astemo Ltd.

Shingo Ooba

Masaki Hano

Hiroyuki Mamada

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.

Rotational angle determining device and phase shift detection method therefor

The drive device measures an open-phase voltage in an energization period in pulse width modulation control, and estimates position information of a rotor based on the measured voltage value, to drive the three-phase brushless motor. This drive device is configured so that, when a voltage pulse width of a set duty cycle is less than or equal to a predetermined value, energization with a voltage pulse width of a minimum duty cycle is performed twice in one period of pulse width modulation, and energization with a voltage pulse width of a correction duty cycle is performed twice in next one period of the pulse width modulation, so that energization with a voltage pulse width of a drive duty cycle corresponding to the set duty cycle is performed, on average in two periods.

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Isesaki, Japan

Shingo Ooba