Patent ID: 8773063

Claim:
A motor drive system comprising: an inverter that supplies power to a three-phase motor by supplying alternating current to three phases of the three-phase motor, the inverter including at least three upper arms and at least three lower arms, each of the at least three upper arms and each of the at least three lower arms including a switching element and a freewheeling diode that are connected in parallel; and a control unit that performs control of the switching elements included in the inverter by switching between (i) supply control of controlling the switching elements so as to cause the inverter to supply alternating current to the three phases and (ii) suspension control of controlling the switching elements so as to cause the inverter to stop the supply of alternating current to the three phases, wherein the control unit switches from the supply control to the suspension control at a timing at which the supply of alternating current to the three phases is to be stopped, and the suspension control is control of: putting and keeping, in a conduction state, a switching element of at least one upper arm, among the at least three upper arms, each corresponding to one of one or more phases through which alternating current flows in a direction entering the three-phase motor at the timing at which the supply of alternating current to the three phases is to be stopped, and putting and keeping the rest of the switching elements included in the inverter in a non-conduction state.