To reduce noise due to voltage correction with one shunt current detection method.
A motor controller (3a) comprises: a current detection unit (21) that detects phase current of a three-phase motor 1 from a detection result of current (idc) flowing between a DC power supply 4 and an inverter 2 driving the motor 1; voltage superposition units (26, 27, and 28) that superpose a command value of a high-frequency superposition voltage (vhγ*, vhδ*) to a command value of a driving voltage for motor drive (vγ*, vδ*); a voltage correction unit (29) that corrects composite voltage of the superposition voltage and the driving voltage to allow detecting phase current for two phases; and a filter unit (23) that generates a filter current signal (iγ, iδ) by reducing a signal component of the superposition current caused by the superposition voltage contained in an original current signal based on the detection result of the current detection unit (21). The motor controller (3a) controls the motor 1 by using the filter current signal.
Inoue On
Masanori Yamamoto