Control device for pole-number switching electric motor

A control device for a pole-number switching electric motor applied to a system including an electric motor capable of switching a number of poles, and an inverter electrically connected to stator windings of the electric motor;

• comprising:
• a basic operation unit that, in a case where a magnitude of a current vector flowing in the stator windings is a current amplitude, and when there is a drive instruction for a number of poles before switching, operates the inverter to control the current amplitude before switching that is the current amplitude corresponding to the number of poles before switching, and when there is a drive instruction for a number of poles after switching, operates the inverter to control the current amplitude after switching that is the current amplitude corresponding to the number of poles after switching;
• and
• a switching operation unit that, in a case of an instruction to switch from the number of poles before switching to the number of poles after switching, in a pole number switching period, operates the inverter to reduce the current amplitude before switching and increase the current amplitude after switching;
• wherein
• the switching operation unit, the pole number switching period, operates the inverter so that a total value of the current amplitude before switching and the current amplitude after switching does not exceed a limiting current value.