Daikin Industries, Ltd.

Kazunobu Ohyama

Yoshinari Asano

Keiji Aota

Shin Nakamasu

Hiroyuki Yamai

Toshinari Kondo

A rotor includes a core extending in a predetermined direction, and a plurality of magnets. The core has parts formed by magnetic materials and extending in the predetermined direction. The parts are arranged in a loop around the part, and face the part through gaps. The magnets are buried in the gaps in the form of a loop in the core. The magnets have pole faces extending in the predetermined direction. In each of the magnets, at least one of ends of the magnet protrudes forward in parallel to the predetermined direction with respect to an end of the part that is on the same side with the at least one of the ends of the magnet.

Core, rotor, motor and compressor

In a pulse-width modulation control unit for an inverter, in the case where the carrier frequency is a normal value of about 5 KHz, the control unit calculates the ON time (the PWM control pattern) at every calculation period corresponding to such a carrier frequency and divides the calculation ON time into plural pulses. This enables the control unit to present apparently such conditions that the PWM control was carried out at a higher carrier frequency (20 KHz or higher), while using a one-chip microcomputer which requires a comparatively long calculation time. Thus, the PWM control by a higher carrier frequency can be attained at a lower cost and by a simple circuit construction.

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Shiga, Japan

Kazunobu Ohyama