Patent ID: 8278865

Claim:
A control device that controls a plurality of inverters respectively provided corresponding to a plurality of alternating-current electric motors so as to control the plurality of alternating-current electric motors by current feedback, wherein: current detection processing to detect currents flowing in coils of each of the plurality of alternating-current electric motors is cyclically performed at times synchronized with a predetermined standard calculation cycle and mutually different from each other; the control device comprises a carrier frequency setting unit that individually selects and sets one of a plurality of carrier frequencies, each of which is a frequency of a carrier for generating switching control signals for the inverter based on a pulse width modulation method, for each of the plurality of inverters, and a switching timing table that specifies a switching timing serving as a permissible timing of switching to a different carrier frequency pair from each of a plurality of carrier frequency pairs each of which is composed of a combination of the carrier frequencies set for each of the plurality of inverters; the switching timing table is a table specifying the switching timing so that the current detection processing for each of the plurality of alternating-current electric motors is performed in accordance with a maximum value or a minimum value of the carrier that is set for the inverter corresponding to each of the alternating-current electric motors; and the carrier frequency setting unit switches the setting of the carrier frequency based on the switching timing obtained from the switching timing table.