Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-03-14
2004-08-24
Nguyen, Tran (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S184000, C310S187000
Reexamination Certificate
active
06781273
ABSTRACT:
FIELD OF THE INVENTION
The invention related to a reluctance motor with a silent pole rotor and stator having winding on either a rotor pole or a stator pole. The invention is a new type of machine in its class because it uses the new technique, multi-circular flux loops (a series of flux loop or a series of circular flux loops), to produce reluctance torque. The invention can implement in alternating current (AC) and direct current (DC) pulse. The invention can apply with a simultaneous phase excitation without flux cancellation between phases. The invention has no a permanent magnet on both a rotor pole and a stator pole, has a simple salient pole and has no physical commutation but commutates by means of electronically commutation.
BACKGROUND OF INVENTION
The invention is built up by using the principle of reluctance torque. This invention can be named ‘a multi-circular flux motor’ the background of the technique came from a short flux loop of a reluctance machine especially a switched reluctance motor. By mean of the short flux loop the electromagnetic flux can be an individual from other flux loops or other phases and a core loss of the machine reduces. As an individual electromagnetic flux loop the motor can be constructed as a servo-machine. However, the short flux loop machine such as a 12/10 pole switched reluctance motor (see invention U.S. Pat. No. 4,883,999) has limitation of designs. The motor cannot have a low number of poles, therefore the motor has to use with a very high frequency to achieve a high speed (the 12/10 switched reluctance motor use 60 Hz to achieve 360 rpm while a 2-pole induction motor use 60 Hz to achieve 3600 rpm). Switched reluctance motor structures are difficult to apply in an AC machine unlike synchronous reluctance motors that can apply in AC machine except just they have a complex rotor which difficult to build.
The benefits over having an AC machine application are:
Using only two current sensors measure 3-phase current.
The machine runs twice times faster than using the DC pulse, for example 50 Hz AC machine run at actual 100 Hz compare to the DC pulse machine such as a switched reluctance motor, because the AC machine is a bipolar current machine while a DC pulse machine is a unipolar current machine.
Using a sinusoidal signal gets a low harmonic.
The principle of this invention can be applied in a linear motor, a rotating machine and a moving part machine. From the prior art shown in
FIG. 1
, a switched reluctance motor tooth shows flux density on both a stator and rotor tooth, the flux density thereby aligned teeth is very condensed than other area and having uneven of saturation level. Conventional switched reluctance motors are usually work by a long flux loop with a fully aligned and fully unaligned condition of their big tooth makes very hard to configure the motor structure. For example a 6/4 pole 3-phase cannot driven by a simultaneous 3-phase excitation and is not appropriate to use an alternating current with their structure. Although some of a switched reluctance motors work by a short flux loop and might be possible to drive by a simultaneous 3-phase excitation but its configuration makes the machine have many teeth. For example, the 12/10 poles 3-phase (see invention U.S. Pat. No. 4,883,999) and a characteristic of the motor type are a highly non-linear, therefore the potential of high-speed application is limited by core loss, switching loss and low inductance ratio making a low torque output and very difficult to control by the problem of a non-linear characteristic of the motor.
SUMMARY OF THE INVENTION
The invention has shared a theory to prior art in a term of reluctance torque between teeth except a winding pole of the invention has been subdivided into plural teeth and work together by a group of short flux loops. A short flux loop that use in a switched reluctance machine, its stroke angle or step distance depends on a tooth width. The way of the invention a winding tooth width can be small as need without an effect to its stroke angle or step distance. The resolution of rotation or linear movement does not depend on the winding tooth width but depends on the winding pole width. This very importance feature makes the invention unique from a conventional short flux loop in a switched reluctance machine. Subdivided teeth with windings of the invention together perform the function as one big winding pole. The invention is not an alignment of teeth but is an alignment of poles, using individual flux loop of those subdivided teeth makes an isolation of each pole and each phase independently therefore the invention can be constructed to be a new type of a machine. By means of using a subdivided tooth, a pole space between phases can be reduced as the tooth space, the invention have a high inductance ratio and the rotor core can use a lightweight material to make a low inertia rotor therefore the invention can be designed to a new type of a machine by its own ways.
The Invention Principle can be Described by the Following:
The invention comprised of a salient pole rotor and a salient pole stator. The rotor pole width is about the stator pole width. Each stator pole (a winding pole) is subdivided into plural stator teeth. All windings of the plural stator teeth of each stator pole are connected together to be one phase winding. The phase winding of each stator pole is excited to perform electromagnetic poles. All odd stator teeth of each stator pole are either North poles or South poles. All even stator teeth of each stator pole are either North poles or South poles. The electromagnetic poles of the odd stator teeth and the even stator teeth are opposite. Each stator tooth generates linking flux loops to both adjacent teeth to complete its electromagnetic flux loops. The both adjacent teeth are a right-hand adjacent tooth and a left-hand adjacent tooth. The electromagnetic flux loops of the stator tooth consist of a left-hand linking flux loop and a right-hand linking flux loop. The left-hand linking flux loop is either a left or right rotation direction. The right-hand linking flux loop is either a left or right rotation direction. The left-hand linking flux loop of the odd stator teeth and the right-hand linking flux loop of the even stator teeth are the same rotation direction. The right-hand linking flux loop of the odd teeth and the left-hand linking flux of the even teeth are the same rotation direction. The linking flux loops are joined together as a series of flux loops or a series of circular flux loops (multi-circular flux loops). The flux loop where a rotor pole-corner is aligned with the stator pole produces reluctance torque to rotate or move the rotor pole, then the next flux loop where the rotor pole-corner is increasingly aligned with the stator pole produces reluctance torque to continue rotate or move until the rotor pole is fully aligned with the stator pole. A stroke angle or a step distance does depend on the stator pole width but does not depend on the small stator teeth.
*Note: the circular flux loop is, [the flux loop] or [the left-hand linking flux loop of odd tooth + the right-hand linking flux loop of even tooth] while the multi-circular flux loops are a series of circular flux loops or a series of flux loops.
The invention using a method of the multi-circular flux loops to produce reluctance torque can be explained in simple drawings shown in
FIG. 2
, FIG.
3
and
FIG. 4
The operation of the simple invention shown in
FIG. 2
comprised with the nonpermanent magnet rotor pole (
1
a
), the non-permanent magnet stator pole (
1
b
), subdivided teeth (
2
) with windings (
5
), tooth spaces (
4
) and stator pole-ends (
3
,
10
). Every tooth of the stator pole is wound, wound inversely to each other adjacent and all are connected together in either a series or a parallel to be one phase winding. The windings are excited to generate the circular flux loop (
6
) inversely rotation direction to each other adjacent. The most effective circular flux loop (
8
) produces relucta
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