Electricity: motive power systems – Synchronous motor systems – Hysteresis or reluctance motor systems
Patent
1998-08-06
2000-01-11
Salata, Jonathan
Electricity: motive power systems
Synchronous motor systems
Hysteresis or reluctance motor systems
318254, H02P 736
Patent
active
06014002&
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for supplying an electronically switched variable reluctance electric motor. It also relates to a supply circuit for the same.
The supply of AC current of an electrically switched variable reluctance motor from a monophase network sector generally uses a rectifier stage and a converter stage comprising electronic switching means controlled by set values and data as to position emitted by detectors, to supply the different phases of this motor. The present invention relates more particularly to the case of electronically switched variable reluctance motors supplied by a converter comprising asymmetric half-bridges.
It is noted that in present processes for the supply of electronically switched motors, and particularly in the supply process used in an asymmetric half-bridge converter, the rectified current delivered by the rectifier stage is subjected to disturbances which can be multiples of the frequency of the sector frequency. These disturbances can lead to exceeding the values of current harmonics permitted by the standard CEI 555-2. At present, this problem is solved by filtering the supply current or the current delivered by the rectifier stage so as to eliminate the current harmonics higher than the sector frequency. There is inserted for example a filter, passive (based on filters L, C) or active (of the PFC type: "Power Factor Correction"), between the rectifier stage and the converter stage. However, the addition of highly capacitative filters (for example 1 mH, 470 .mu.F) leaves remaining the problem of uneven low frequency harmonics. With a weakly capacitative sector filter (1.5 mH, 20 .mu.F), there are observed harmonics connected to the control frequency. Moreover, the addition of a PFC filter upstream of the converter stage leads to significant and prohibitive increase in cost of the electronics when the power to be controlled exceeds several hundreds of watts.
The object of the invention is to overcome these drawbacks by providing a process for the supply of an electronically switched variable reluctance motor, using magnetization and demagnetization sequences and in which the power transferred in the course of these sequences is eventually used to compensate or eliminate the disturbances in the supply current.
These objects are achieved with a process to supply an electronically switched variable reluctance polyphase electric motor from a source of rectified voltage, comprising for each phase: each phase, and voltage is applied to each phase.
According to the invention, the process moreover comprises: of rectified voltage, magnetic energy then stored in at least one of said phases is substantially maintained in the latter.
There is to be understood more generally by disturbance of the current, any deformation of the current wave relative to a reference current wave, this deformation being adapted to be induced by any physical phenomenon, identified or not, of internal or external origin, to the drive system in question.
As to the difference in the conventional supply processes using asymmetric half-bridges, in which the energy transfers between the source and the phases are conditioned only as to angular parameters (opposition, conjunction and perhaps dephasing) and as to operational and safety set values, in the process according to the invention, these energy transfers can be retarded or inhibited so as to compensate the disturbances detected in the supply current, with the object of observing existing standards of electromagnetic compatibility.
In a preferred embodiment of the process according to the invention, the disturbances affecting the rectified supply current are detected by measuring this current and by comparing it to a reference current wave. But there could also be provided any type of estimation of the rectified supply current, not using an effective measurement of the current.
The process according to the invention preferably comprises the detection, during a magnetization sequence of one phase, a supply current higher than the amp
REFERENCES:
patent: 3639819 (1972-02-01), Wiart
patent: 5166591 (1992-11-01), Stephens et al.
patent: 5689164 (1997-11-01), Hoft et al.
patent: 5811954 (1998-09-01), Randall
patent: 5923141 (1999-07-01), McHugh
By P.C. Kjaer et al., "A New Energy Optimizing Control Strategy for Switched Reluctance Motors", 1994 IEEE, vol. 1, pp. 48-55.
By G.H. Rim et al., "A Novel Converter Topology for Switched Reluctance Motor Drives Improving Efficiency and Simplifying Control Strategy", 1994 IEEE, pp. 937-942.
Moulinex (S.A.)
Salata Jonathan
LandOfFree
Method for powering an electronically switched variable-reluctan does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for powering an electronically switched variable-reluctan, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for powering an electronically switched variable-reluctan will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1464709