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A CONTROL METHOD FOR PERMANENT MAGNET SYNCHRONOUS MOTORS WITH TRAPEZOIDAL ELECTROMOTIVE FORCE
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| Author(s) |
L. Schülting; H.-Ch. Skudelny |
| Abstract |
In this paper, a control method for a permanent magnet synchronous motor (PSM) fed by a voltage source inverter (VSI) is described. The electromotive force (EMF) has trapezoidal waveforms. Thus the current in each phase of the PSM must be constant for a third of a period in order to achieve a constant torque. The control method presented here needs only one current sensor in the DC link. During the commutation process in the VSI from one phase to the next an overcurrent occurs in some operating conditions of the drive due to the special form of current sensing. This overcurrent endangers the switches of the inverter and must be prevented. Therefore a control method is developed which considers the commutation process in the VSI. A unit called "chopper" was added to the hysteresis controller to avoid the overcurrent in the switches. This proposed controller shows the same good dynamic and steady-state behaviour as schemes sensing the load currents. General equations of the VSI are given that take into account the status of the whole current controller. Especially during the commutation process the calculations point out that the switches are reliably protected. Detailed simulation results based on the analytical study are presented and verified by laboratory tests. |
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| Filename: | Unnamed file |
| Filesize: | 3.042 MB |
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| Type |
Members Only |
| Date |
Last modified 2019-08-06 by System |
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