Patent No. | 9,225,270 |
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Issue Date | December 29, 2015 |

Title | Current Control Device Of Synchronous Motor |

Inventorship | Kenji Takahashi, Yamanashi (JP) |

Assignee | FANUC CORPORATION, Yamanashi (JP) |

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.

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.