INVERTER CONTROLLER AND ON VEHICLE FLUID MACHINE

An inverter controller is configured to control an inverter circuit that drives an on-vehicle electric motor by using an on-vehicle electricity storage device. The inverter controller includes a two-phase voltage command value deriving unit that derives two-phase voltage command values on the basis of an external command value delivered from an external device and an acquisition result of a speed acquiring unit, and a three-phase voltage command value deriving unit that derives three-phase voltage command values on the basis of the two-phase voltage command values. The three-phase voltage command value deriving unit derives the three-phase voltage command values on the basis of a voltage utilization factor, which is calculated on the basis of the two-phase voltage command values and the acquisition result.