METHOD OF CONTROLLING A CURRENT OF A MOTOR AND CONTROL DEVICE OF A MOTOR

• US 20130221879A1
• Filed: 11/09/2010
• Published: 08/29/2013
• Est. Priority Date: 09/15/2009
• Status: Active Grant

• Current Assignee: Toshiba Kikai Kabushiki Kaisha (Toshiba Machine Company Limited)
• Original Assignee: Toshiba Kikai Kabushiki Kaisha (Toshiba Machine Company Limited)
• Inventors: Yokokawa, Narutoshi
• Granted Patent: US 9,054,622 B2
• Time in Patent Office: Days
• US Class Current: 318/400.02
• CPC Class Codes: H02P 21/22 Current control, e.g. using a current control loop

Abstract

The present invention is a control device of a motor, for drawing out a capacity of the motor as much as possible so as to achieve a high-speed high-output performance thereof while securing a stability, including: a converter unit configured to rectify and smooth an AC voltage, and to output a DC main circuit voltage; an inverter unit configured to pass a current for driving the motor, with the use of the main circuit voltage; a current detector configured to detect an armature current passing through the motor; a position detector disposed on the motor, the position detector being configured to detect a motor speed; and a current control unit configured to control, upon reception of a q-axis current command (Iqr), the armature current passing through the motor, by outputting a signal for driving the inverter unit, with the use of data from the current detector and data from the position detector.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. (canceled)

5. A method of controlling a current of a motor, with the use of a control device of a motor, the control device of a motor including:

a converter unit configured to rectify and smooth an AC voltage, and to output a DC main circuit voltage;

an inverter unit configured to pass a current for driving the motor, with the use of the main circuit voltage;

a current detector configured to detect an armature current passing through the motor;

a position detector disposed on the motor, the position detector being configured to detect a motor speed; and

a current control unit configured to control, upon reception of a q-axis current command (Iqr), the armature current passing through the motor, by outputting a signal for driving the inverter unit, with the use of data from the current detector and data from the position detector, wherein

the current control unit includes;

a current detection unit configured to convert a signal from the current detector to data which can be processed by the current control unit;

a three-phase to two-phase conversion unit configured to convert a three-phase current of respective phases, which has been outputted by the current detection unit, to a two-phase current;

a d-axis current command generation unit configured to generate a d-axis current command (Idr);

a limit processing unit configured to calculate, upon the reception of the q-axis current command (Iqr), the q-axis current limit value (Iqlimit) from √

(Imax̂

2−

Idr̂

2) with the use of a maximum value (Imax) of a composite current command value of q-axis and d-axis and the d-axis current command (Idr), and to make the q-axis current command (Iqr) to work such that;

when the q-axis current command (Iqr) is equal to or greater than 0 and is greater than the q-axis current limit value (Iqlimit), a q-axis current limit command value (Iqrl) is limited to the q-axis current limit value (Iqlimit) and a limit flag is turned on;

when the q-axis current command (Iqr) is equal to or greater than 0 and is equal to or less than the q-axis current limit value (Iqlimit) or when the q-axis current command (Iqr) is less than 0 and is equal to or greater than −

Iqlimit, the q-axis current limit command value (Iqrl) is made into the q-axis current command (Iqr) and the limit flag is turned off; and

when the q-axis current command (Iqr) is less than 0 and is less than −

Iqlimit, the q-axis current limit command value (Iqrl) is limited to −

Iqlimit and the limit flag is turned on;

a PI compensation unit for increasing a gain, an output value (Iqrl) of the limit processing unit subtracted by a q-axis current (Iq), which corresponds to an output value of the three-phase to two-phase conversion unit, being inputted into the PI compensation unit;

a VqLimit processing unit (for Vq) configured to limit a voltage command (Vq), which has been outputted by the PI compensation unit, to a preset limit value;

a second PI compensation unit for increasing a gain, the d-axis current command (Idr) subtracted by a d-axis current (Id), which corresponds to an output value of the three-phase to two-phase conversion unit, being inputted into the second PI compensation unit;

a VdLimit processing unit (for Vd) configured to limit a voltage command (Vq), which has been outputted by the second PI compensation unit, to a preset limit value;

a two-phase to three-phase conversion unit configured to convert a two-phase voltage (Vql and Vdl), which has been outputted by the VqLimit processing unit and the VdLimit processing unit, to a three-phase voltage, in order to actually drive the motor; and

a PWM conversion unit configured to convert a signal, which has been outputted by the two-phase to three-phase conversion unit, to a pulse.

6. The method of controlling a current of a motor according to claim 5, the method further including:

calculating an electric angular velocity (ω

) of the motor based on a signal from the position detector; and

compensating the d-axis current command (Idr) with the use of the two-phase voltage (Vql and Vdl) and the electric angular velocity (ω

).

7. A control device of a motor, the control device of a motor including:

a converter unit configured to rectify and smooth an AC voltage, and to output a DC main circuit voltage;

an inverter unit configured to pass a current for driving the motor, with the use of the main circuit voltage;

a current detector configured to detect an armature current passing through the motor;

a position detector disposed on the motor, the position detector being configured to detect a motor speed; and

a current control unit configured to control, upon reception of a q-axis current command (Iqr), the armature current passing through the motor, by outputting a signal for driving the inverter unit, with the use of data from the current detector and data from the position detector, wherein

the current control unit includes;

a current detection unit configured to convert a signal from the current detector to data which can be processed by the current control unit;

a three-phase to two-phase conversion unit configured to convert a three-phase current of respective phases, which has been outputted by the current detection unit, to a two-phase current;

a d-axis current command generation unit configured to generate a d-axis current command (Idr);

a limit processing unit configured to calculate, upon the reception of the q-axis current command (Iqr), the q-axis current limit value (Iqlimit) from √

(Imax̂

2−

Idr̂

2) with the use of a maximum value (Imax) of a composite current command value of q-axis and d-axis and the d-axis current command (Idr), and to make the q-axis current command (Iqr) to work such that;

when the q-axis current command (Iqr) is equal to or greater than 0 and is greater than the q-axis current limit value (Iqlimit), a q-axis current limit command value (Iqrl) is limited to the q-axis current limit value (Iqlimit) and a limit flag is turned on;

when the q-axis current command (Iqr) is equal to or greater than 0 and is equal to or less than the q-axis current limit value (Iqlimit) or when the q-axis current command (Iqr) is less than 0 and is equal to or greater than −

Iqlimit, the q-axis current limit command value (Iqrl) is set to the q-axis current command (Iqr) and the limit flag is turned off; and

when the q-axis current command (Iqr) is less than 0 and is less than −

Iqlimit, the q-axis current limit command value (Iqrl) is limited to −

Iqlimit and the limit flag is turned on;

a PI compensation unit for increasing a gain, an output value (Iqrl) of the limit processing unit subtracted by a q-axis current (Iq), which corresponds to an output value of the three-phase to two-phase conversion unit, being inputted into the PI compensation unit;

a VqLimit processing unit (for Vq) configured to limit a voltage command (Vq), which has been outputted by the PI compensation unit, to a preset limit value;

a second PI compensation unit for increasing a gain, the d-axis current command (Idr) subtracted by a d-axis current (Id), which corresponds to an output value of the three-phase to two-phase conversion unit, being inputted into the second PI compensation unit;

a VdLimit processing unit (for Vd) configured to limit a voltage command (Vq), which has been outputted by the second PI compensation unit, to a preset limit value;

a two-phase to three-phase conversion unit configured to convert a two-phase voltage (Vql and Vdl), which has been outputted by the VqLimit processing unit and the VdLimit processing unit, to a three-phase voltage, in order to actually drive the motor; and

a PWM conversion unit configured to convert a signal, which has been outputted by the two-phase to three-phase conversion unit, to a pulse.

8. A control device of a motor according to claim 7, wherein

the current control unit further includes a position detection unit configured to calculate an electric angular velocity (ω

) of the motor based on a signal from the position detector; and

the d-axis current command generation unit compensates the d-axis current command (Idr) with the use of the two-phase voltage (Vql and Vdl) and the electric angular velocity (ω

).