Current control method for zero torque ripple and maximum efficiency of brushless dc motor
| Autor: | Osamu Ichinokura, T. Jinzenji, Takeshi Shimada, Tadaaki Watanabe, Takeshi Chigiri |
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| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | IEEJ Transactions on Industry Applications. 116:1276-1282 |
| ISSN: | 1348-8163 0913-6339 |
| DOI: | 10.1541/ieejias.116.1276 |
| Popis: | Since the rare metal magnets show the high saturation flux density, the ferrite magnets of the magnetic field poles of PM (permanent magnet) motors have been substituted for them in recent years. The feature of the rare metal magnet realize small size or high power BLM (brushless dc motors). However, the ordinary magnetic field poles of the PM motors generate higher harmonic flux and cause torque ripple. They are usually removed by short pitch winding, skew slot method and so on. But these methods show a drawback to lower efficiency. This problem is important especially for high power BLM.Recently new methods have been proposed to realize zero torque ripple and high efficiency drive at the same time. The methods optimize the reference current waveform which is calculated by motor EMF (electromotive force)in advance, and current are controlled to follow up the optimized one. However, the one method assumes try and error. The other one doesn't prove that it realizes maximum efficiency and zero torque ripple drive at the same time. And they have much room to improvement to apply to BLM.This paper proposes the simultaneous equations which give the accurate relation among instantaneous torque, EMF and current, and proposes a new index CSR which evaluates the relation between copper loss and current waveform. Then the optimized current waveform to drive BLM with zero torque ripple and maximum efficiency is calculated by using new equations and CSR. For this waveform includes triplex harmonic order, normal three phase full bridge inverter can't be used. This paper proposes four arm full bridge inverter which can apply triplex order current to BLM. Experimental result proves this method is available. |
| Databáze: | OpenAIRE |
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