Patent ID: 9225270
Filing Date: 2015-12-29
Classification: H02P

Abstract:
1. A current control device of a synchronous motor, generating a current command in a predetermined sampling period on the basis of an orthogonal dq coordinate system, the current control device comprising: a provisional d-phase current command calculation unit calculating a provisional d-phase current command on the basis of a torque command, a current at no load, and a current at maximum load; a voltage amplitude calculation unit obtaining a voltage command vector, which is an output of a current control in a previous sampling period, that is one cycle prior to the present sampling period, and calculating a magnitude of the voltage command vector; a voltage ratio calculation unit determining a voltage ratio between the magnitude of the voltage command vector and a maximum output voltage of an amplifier; a target d-phase current calculation unit obtaining a d-phase current command in the previous sampling period, and calculating a target d-phase current command from the voltage ratio and the d-phase current command; a correction value calculation unit determining a correction value by passing a difference between the provisional d-phase current command in the present sampling period and the target d-phase current command through a low-pass filter; and an adder adding the correction value to the provisional d-phase current command in the present sampling period in order to calculate a new d-phase current command.