Control apparatus for rotary electric machine

A control apparatus for controlling, via a power converter for power conversion of a direct-current voltage input thereto, a multiphase rotary electric machine that has a rotating magnetic field, the control apparatus comprising:

• a command voltage generator configured to generate a command voltage with first positive and negative peaks relative to a zero voltage level for at least one phase of the multiphase rotary electric machine;
• a carrier signal generator configured to generate a cyclic carrier signal having:
• cyclic carrier pulses with second positive and negative peaks relative to the zero voltage level;
• and
• a phase synchronized with the rotating magnetic field;
• and
• a controller configured to control the carrier signal generator,
• the controller being configured to perform a comparison between the command voltage and the cyclic carrier signal to thereby perform one of:
• as a first result of the comparison, pulse-width modulation upon an amplitude of each of the first positive and negative peaks of the command voltage being within or identical to the corresponding one of the second positive and negative peaks of the cyclic carrier signal;
• or
• as a second result of the comparison, single-pulse modulation upon the amplitude of each of the first positive and negative peaks of the command voltage being outside the corresponding one of the second positive and negative peaks of the cyclic carrier signal,
• the pulse-width modulation being configured to generate, for each cycle of the command voltage, plural drive pulses for driving the power converter,
• the single-pulse modulation being configured to generate, for each cycle of the command voltage, a single positive pulse and a single negative pulse for driving the power converter,
• in the single-pulse modulation, the amplitude of each of the first positive peaks of the command voltage being higher than the amplitude of the corresponding one of the second positive peaks of the cyclic carrier signal, and the amplitude of each of the first negative peaks of the command voltage being lower than the amplitude of the corresponding one of the second negative peaks of the cyclic carrier signal.