Matrix converter and method for controlling matrix converter

A method for controlling a matrix converter, the method comprising:

• detecting a voltage of an alternating current (AC) power supply;
• determining whether the voltage of the AC power supply is not more than a predetermined level;
• turning ON, when the voltage of the AC power supply exceeds the predetermined level, all of a plurality of unidirectional switching elements constituting a plurality of bidirectional switches that connect each phase of the AC power supply with each phase of a rotary electric machine, to performing power conversion control;
• and
• performing, when the voltage of the AC power supply is not more than the predetermined level, one operation and switching two operations to perform the power conversion control, the one operation always turning ON the unidirectional switching elements enabling a current to flow between two of the phases of the AC power supply, one of the two operations always turning ON the unidirectional switching elements enabling a current to flow between one-pair phases of the phases of the rotary electric machine, and the other of the two operations turning ON the unidirectional switching elements enabling a current to flow between two-pair phases of the phases of the rotary electric machine, among the unidirectional switching elements constituting the bidirectional switches.