Abstract: A motor drive system includes: a first inverter connected to one end of an open-end winding of a three-phase motor, an input voltage from a single-phase AC power source being rectified into a rectified voltage and input to the first inverter; a second inverter connected to another end of the open-end winding and including a DC link capacitor; and a control unit that controls the first inverter so that a first inverter output voltage supplied from the first inverter to the three-phase motor is in phase with a motor current flowing in the three-phase motor, controls the second inverter to supply reactive power to the three-phase motor by making a second inverter output voltage supplied from the second inverter to the three-phase motor orthogonal to the motor current in order to make an instantaneous power supplied from the DC link capacitor to the three-phase motor zero, and also controls the second inverter so that a q-axis component of the second inverter output voltage orthogonal to a d-axis component, which