In order to compensate for detent torques (caused by non-sinusoidal EM curves), the torque-forming q-current is entered in a table and "taught-in".
After elimination of the offsets (compensated table), the q-current is inverted and fed-in as the pre-control value of the control.
The compensation function can be described by means of compensating currents (q-current, scope signal "isqref_comp") dependent on a position (electrical angle, scope signal "epsRS"). A "teach-in" is used to import the values into a table. With parameter P 0382 CON_TCoggComp the method to be used is selected:
The interpolation between the table values is linear. The characteristic is not saved automatically; it must be saved manually. The progress of the teach process and the compensation can be tracked on the scope. The signal 55_isqCoggingTeach indicates the momentary output value of the teach table during teach mode, while 56_isqCoggingAdapt contains the momentary value from the compensation table.
Vorgehensweise: Populate table (teach EPSRS)
Vorgehensweise: Populate table (teach ABSPOS)
Vorgehensweise: Teach-in (teach EPMS)
Parameters
P. no. | Parameter name | Function |
---|---|---|
P 0380 | CON_TCoggAddTab | Taught-in values (EPSRS) |
P 0382 | CON_TCoggComp | Selection of process |
(1) | EPSRS | Compensation referred to the electrical angle; example – three-pole pair motor: The table in P 0380 CON_TCoggAddTab is populated three times within one mechanical motor revolution. The compensation is effected with the averaged table values. |
(2) | ABSPOS | Compensation referred to a freely definable position. |
(3) | EPMS | Compensation referred to one mechanical revolution |
(4) | ENCPOS | Compensation referred to one revolution of the encoder |
P 0385 | CON_TCoggTeachCon | Selection of teach function |
(1) | TeachTab(1) | Activation of Teach function EPSRS |
(2) | TeachTab(2) | Activation of Teach function APSPOS |
(3) | CalcCorTab(3) | Calculation of compensation |
(4) | RESET(4) | Reset table values |
(5) | COMPTAB(5) | Calculation of compensation APSPOS |
P 0440 | CON_TAB_TabIndex | Compensation table: Index |
P 0441 | CON_TAB_TabVal | Compensation table: Actual |
P 0442 | CON_TAB_PosStart | Compensation table: Start position |
P 0443 | CON_TAB_PosDelta | Compensation table: Position delta |
P 0445 | CON_TAB_TeachDir | Compensation table: Direction of rotation Teach mode |
P 0446 | CON_TAB_OutVal | Compensation table: Output value |
Tabelle: Detent torque compensation
Copyright © LTi DRiVES GmbH, Januar 2013, ID-Nr.: 0842.26B.1-00 DE