Source: http://www.google.com/patents/US6788180?dq=5,266,072
Timestamp: 2017-05-27 09:22:25
Document Index: 501486159

Matched Legal Cases: ['Application No. 60', 'Application No. 20015689', 'arts 10', 'art 16', 'arts 16', 'arts 16', 'arts 16']

Patent US6788180 - Controllable transformer - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA controllable transformer device comprising a body of a magnetic material, a primary winding wound round the body about a first axis, a secondary winding wound round the body about a second axis at right angles to the first axis, and a control winding wound the body about a third axis, coincident with...http://www.google.com/patents/US6788180?utm_source=gb-gplus-sharePatent US6788180 - Controllable transformerAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS6788180 B2Publication typeGrantApplication numberUS 10/300,752Publication dateSep 7, 2004Filing dateNov 21, 2002Priority dateNov 21, 2001Fee statusPaidAlso published asCA2467989A1, CA2467989C, CA2729421A1, CA2729421C, CN1615462A, DE60215381T2, EP1449043A1, EP1449043B1, US7061356, US20030117251, US20050110605, WO2003044613A1Publication number10300752, 300752, US 6788180 B2, US 6788180B2, US-B2-6788180, US6788180 B2, US6788180B2InventorsEspen Haugs, Frank StrandOriginal AssigneeMagtech AsExport CitationBiBTeX, EndNote, RefManPatent Citations (15), Non-Patent Citations (4), Referenced by (2), Classifications (8), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetControllable transformer
US 6788180 B2Abstract
A controllable transformer device comprising a body of a magnetic material, a primary winding wound round the body about a first axis, a secondary winding wound round the body about a second axis at right angles to the first axis, and a control winding wound the body about a third axis, coincident with the second axis. The device can be employed to provide a frequency controlled power supply.
What is claimed is: 1. A controllable transformer device comprising;
a body of a magnetic material; a primary winding wound round the body about a first axis; a secondary winding wound round the body about a second axis at right angles to the first axis; and a control winding wound around the body about a third axis, coincident with the second axis. 2. The controllable transformer according to claim 1 wherein the body comprises a hollow core with an internal winding compartment and an external winding compartment.
3. The controllable transformer according to claim 2 wherein the primary winding is arranged in the external winding compartment and the secondary winding and the control winding are arranged in the internal winding compartment.
4. The controllable transformer according to claim 2 wherein the primary winding is arranged in the internal winding compartment and the secondary and the control winding are arranged in the external winding compartment.
5. The controllable transformer according to one of the preceding claims, further comprising magnetic field connectors.
6. A method for controllable conversion of a primary alternating electrical signal to a secondary alternating electrical signal using a controllable transformer comprising a body of a magnetic material, a primary winding wound round the body about a first axis, a secondary winding wound round the body about a second axis at right angles to the first axis, and a control winding wound around the body about a third axis, coincident with the second axis, the method comprising the steps of:
supplying the primary winding with the primary alternating electrical signal; supplying the control winding with an alternating voltage which is shifted in phase relative to the primary alternating electrical signal by one of 0° and 180°; and supplying the control winding with a variable current, wherein a conversion ration of the transformer is controlled by the variable current. 7. A method according to claim 6, wherein the control winding is supplied with a pulsed AC current.
8. A method for controllable conversion of a primary alternating electrical signal to a secondary alternating electrical signal by a controllable transformer comprising a magnetic material having magnetic domains, the method comprising the steps of:
supplying a primary winding with a primary alternating signal; supplying a control winding with an alternating voltage which is shifted in phase relative to the primary alternating signal by one of 0° and 180°; adjusting the amplitude of the alternating voltage to change at least one of domain directions in the magnetic material and a magnetization angle between the primary winding and a secondary winding; introducing an inductance in a control circuit; and adding an electromagnetic force from the secondary winding to an electromagnetic force from the control winding; whereby a voltage transfer of the transformer is changed, whereby the magnetization angle between the primary winding and the secondary winding is influenced by the added electromagnetic force, whereby an effect of a direct transformative connection between the secondary winding and the control winding is suppressed, whereby a phase angle rotation between the primary winding and the secondary winding varies according to load conditions, whereby the phase angle rotation is compensated for, and whereby a controlled transformation effect is achieved by obtaining a primary winding response to a load change in a secondary load. 9. A method of aligning domains in a magnetisable core of a transformer, the transformer comprising a first winding, a second winding, and a third winding wherein the first winding and the second winding are oriented orthogonal to one another, the method comprising the steps of:
energizing the first winding; monitoring a current in the first winding; monitoring a current in the second winding; and exciting the third winding to compensate for domain changes established by the second winding. 10. A method of controlling the orientation of a field in a transformer, the method comprising the steps of:
generating a primary field in a first direction; generating a secondary field in a second direction orthogonal to the first direction; generating a control field in a third direction which is coincident to the first direction; and adjusting the control field to control a direction of the primary field.
This application claims priority to U.S. Provisional Application No. 60/633,136, filed Nov. 27, 2001, and to Norwegian Application No. 20015689, filed Nov. 21, 2001. The contents of each of these applications are incorporated herein by reference.
FIGS. 12-15 illustrate various embodiments of the magnetic field connectors in the said second embodiment of the invention.
FIGS. 16-29 illustrate various embodiments of the tubular bodies in the second embodiment of the invention.
FIGS. 30-35 illustrate different aspects of magnetic field connectors for use in the second embodiment of the invention.
FIGS. 39-41 illustrate special embodiments of magnetic field connectors for use in the third embodiment of the invention.
The invention will now be explained in principle in connection with FIGS. 1a and 1 b. In this description, the expressions “primary winding” and “secondary winding” are used to designate a winding where energy is input (i.e., the primary) and a winding which is meant for connection to a load (i.e., the secondary) as is usual in transformers. The expression “control winding” denotes a winding which controls the transformer's transformation ratio. In the device according to an embodiment the invention, the primary and the secondary windings are wound round orthogonal axes.
FIG. 1a illustrates a device comprising a body 1 of a magnetisable material that forms a closed magnetic circuit. This magnetisable body or core 1 may be annular in form or of another suitable shape. Around the body 1 is wound a first main winding 2, where the direction of the magnetic field H1 (corresponding to the direction of the flux density B1) that will be produced when the main winding 2 is excited will conform to the magnetic circuit. The main winding 2 resembles a winding in an ordinary transformer. In an embodiment the device comprises a second main winding 3, which is wound round the magnetisable body 1 in the same way as the main winding 2 and which will thereby provide a magnetic field extending substantially along the body 1 (i.e. parallel to H1, B1). Finally, the device comprises a third main winding 4, which in a preferred embodiment of the invention extends internally along the magnetic body 1. The magnetic field H2 (and thereby the flux density B2) that is created when the third main winding 4 is excited, will have a direction that is at right angles to the direction of the fields in the first and the second main winding (direction of H1, B1). According to an embodiment of the invention, the third main winding 4 constitutes a primary winding, the first main winding 2 constitutes the secondary winding and the second main winding 3 constitutes the control winding. In one embodiment, however, the turns in the main winding follow the field direction from the control field and the turns in the control winding follow the field direction of the working field.
FIGS. 1b-1 g illustrate the definition of the axes and the direction of the various windings and the magnetic body. As far as the windings are concerned, we shall call the axis the direction normal to the surface defined by each turn. The secondary winding 2 will have an axis A2, the control winding 3 an axis A3 and the primary winding 4 an axis A4.
With regard to the magnetisable body 1, the longitudinal direction will vary according to the shape. If the body is elongated, the longitudinal direction A1 will coincide with the body's longitudinal axis. If the magnetic body is square as illustrated in FIG. 1a, it will be possible to define a longitudinal direction A1 for each leg of the square. Where the body is tubular, the longitudinal direction A1 will be the tube's axis, and for an annular body the longitudinal direction A1 will follow the circumference of the ring.
As already mentioned, in FIGS 1 a and 2 a winding 4 is the primary winding and winding 2 the secondary winding while winding 3 is the control winding. FIG. 4 shows A1 as the flux area for both secondary winding 2 and control winding 3. This area may be called the area for the internal winding compartment (i.e., iws) A2 is the flux area for the primary winding 4. The area A2 may also be referred to as the area of the external winding compartment (i.e., ews). Depending on the kind of conversion and connection required, it will be possible to give the areas A1 and A2 equal or unequal dimensions.
In these FIGS. 6c and 6 d, Vp represents a voltage on the primary winding and Vs a voltage on the secondary winding. At the same time Vp denotes the winding axis of the primary winding and Vs the winding axis of the secondary winding. Flux produced or linked by the primary winding will then have the direction of Vp while flux produced or linked by the secondary winding will have the direction of Vs. In FIG. 6c the domains are aligned according to the primary voltage Vp and their magnetisation B will vary roughly as shown in the Figure. The magnetic field H produced by this primary winding will vary from positive to zero and from zero to a negative value.
In FIG. 6d, a control field Bkdc is introduced by activating the control winding and exciting it with DC. The control field is added to the primary field Bkvp, establishing a magnetisation Bkr, as illustrated. Since a constant field is added to a sinusoidal field, the sum will change sinusoidally in direction and sinusoidally in field strength. The simplified diagram 6 d illustrates that we obtain a change in domain alignment direction that becomes a product of two sinus functions. Both direction and field strength for the resulting field are changed sinusoidally. When domains change size and direction, the body's magnetisation will be altered accordingly. This induces voltages in windings where the domains are under an angle that is not orthogonal to the windings.
Bks=Bkr·Bkvp 3)
Bkp=Kvp2·sin 2 (w·t) 4)
According to an embodiment of the invention the magnetisation is controlled by means of a pulsed DC or pulsed AC control current in a secondary control winding orthogonal to the primary control winding. For example, controlling the magnetisation stepwise with increased voltage from the primary winding with an AC control current in the control winding as illustrated in FIG. 6e, the direction of the domains will be kept constant at, e.g., 30 degrees and only the field strength of the magnetisation will be changed in order to avoid a change in both strength and direction simultaneously.
For the magnetic circuit according to an embodiment of the invention, the constant domain direction will be achieved by means of an accurate dosing of the control current in relation to the primary winding's magnetisation current and ampereturn balance with the secondary winding. In an ordinary transformer as illustrated in FIG. 6g, the magnetisation current established by the primary winding will be given by the flux required to generate a counter-induced voltage Ep according to Faraday's law. I _  p = V _  p - E _  p Rp 6 ) Ep: Voltage induced in the primary winding
{overscore (I)}p={overscore (I)}fe+{overscore (I)}m 7)
Disregarding leakage fields, the common flux for primary and secondary winding is given by Φ   m = Np · Im Rcore 7 ) Np: Primary winding's number of turns
With an open secondary circuit there is only magnetisation current in the primary winding. According to Lenz's law, electromotive voltage induced in the secondary winding (i.e., emf) will be in such a direction that it will counteract the flux change that created it. When the secondary winding is connected to a load (the switch S in FIG. 6g is closed), the secondary winding's own magnetomotive force Fs (i.e., mmf) or flux Φs will immediately (in the transient sequence) be established, which will be in the opposite direction to mmf from the primary winding Fp. This result is illustrated in FIG. 6g. In a moment, the flux in the core will decrease to Φ   m = Np · im - Ns · is Rcore 8 ) where is the secondary current and Ns the number of turns in the secondary winding. The flux reduction will lead to a reduction in the induced voltage in the primary winding and thereby according to equation 6) an increase in the primary current. This increased primary current, which is the load current component in the primary current, adds its mmf vectorially to the magnetisation component Np*im, and causes an increase in the primary flux: Φ   m = Np · im + Np · ip , load - Ns · is Rcore 9 ) The primary current increases until Np·Ip, load−Ns·is and then Φm and Ep are on the same level as they were before the switch was closed. In stationary operation we will have a current in the primary winding:
{overscore (I)}p={overscore (I)}fe+{overscore (I)}m+Ip,load 10)
FIG. 6h illustrates the linear part of the magnetisation curve for a standard commercial core plate.
FIGS. 7a and 7 b illustrate the flux densities B1 (where the field H1 is established by the secondary winding) and B2 (corresponding to the primary current). The ellipse illustrates the saturation limit for the B fields, i.e. when the B field reaches the limit, this will cause the material of the magnetisable body 1 to reach saturation. The design of the ellipse's axes will be given by the field length and the permeability of the two fields B1 (H1) and B2 (H2) in the core material of the magnetisable body 1.
FIG. 9 illustrates the same embodiment of a magnetically influenced connector according to the invention, where FIG. 9a illustrates the assembled connector and FIG. 9b is an end view of the connector.
FIG. 10 illustrates a section along line II in FIG. 9b. As illustrated, for example, in FIG. 10, the magnetisable body 1 is composed inter alia of two parallel tubes 6 and 7 made of a magnetisable material. An electrically insulated conductor 8 (FIGS. 9a, 10) is passed continuously in a path through the first tube 6 and the second tube 7 a quantity of N times, where N=1, . . . r. The conductor 8 forms the primary main winding 2, with the conductor 8 extending in the opposite direction through the two tubes 6 and 7, as is clearly illustrated in FIG. 10. Even though the conductor 8 is only shown extending twice through the first tube 6 and the second tube 7, it should be self-explanatory that it is possible for the conductor 8 to extend through the respective tubes either only once or possibly several times (as indicated by the fact that the winding number N can vary from 0 to r), thereby creating a magnetic field H1 in the parallel tubes 6 and 7 when the conductor is excited. A combined control and secondary winding 4,4′, composed of the conductor 9, is wound round the first tube and the second tube (6 and 7 respectively), in such a manner that the direction of the field H2 (B2) that is created on the said tubes when the winding 4 is excited will be oppositely directed, as indicated by the arrows for the field B2 (H2) in FIG. 8. Magnetic field connectors 10, 11 are mounted at the ends of the respective tubes 6, 7 in order to interconnect the tubes fieldwise in a loop. The conductor 8 will be able to convey a load current I1 (FIG. 9a). The tubes' 6, 7 length and diameter will be determined on the basis of the power and voltage that have to be connected. The number of turns N1 on the main winding 2 will be determined by the reverse blocking ability for voltage and the cross-sectional area for the magnitude of the working flux Φ2. The number of turns N2 on the control winding 4 is determined by the conversion ratio required for the special transformer.
FIG. 11 illustrates an embodiment where the primary and the secondary main windings have been interchanged. The solution in FIG. 11 differs from that illustrated in FIGS. 9a and 10 by the fact that instead of a single insulated conductor 8, which is passed through the tubes 6 and 7, two separate oppositely directed conductors pass through the tubes 6, 7. In this embodiment, secondary conductors 8 and control conductors 8′ are employed, in order to achieve a voltage converter function in the magnetically influenced device according to the invention. The design basically resembles that illustrated in FIGS. 8, 9 and 10. The magnetisable body 1 comprises two parallel tubes 6 and 7. An electrically insulated secondary conductor 8 is passed continuously in a path through the first tube 6 and the second tube 7 a quantity of N1 times, where N1=1, . . . r. The conductor 8 extends in the opposite direction through the two tubes 6 and 7. An electrically insulated control conductor 8′ is passed continuously in a path through the first tube 6 and the second tube 7 for a quantity of N1′ times, where N1′=1, . . . r. The conductor 8′ extends in the opposite direction relative to the conductor 8 through the two tubes 6 and 7. At least one primary winding 4 and 4′ is wound round the first tube 6 and the second tube 7 respectively. As a result, the field direction created on the tubes is oppositely directed. In a similar manner as the embodiment according to FIGS. 8, 9 and 10, the magnetic field connectors 10, 11 are mounted at the end of the respective tubes 6, 7 in order to interconnect the tubes 6 and 7 fieldwise in a loop and form the magnetisable body 1. Even though for the sake of simplicity in the drawings, the conductor 8 and the conductor 8′ are illustrated with only one pass through the tubes 6 and 7, it will be immediately apparent that both the conductor 8 and the conductor 8′ can be passed through the tubes 6 and 7 for a quantity of N1 and N1′ times respectively. The length and diameter of tubes' 6 and 7 will be determined on the basis of the power and voltage that have to be converted. For a transformer with a conversion ratio (N1:N′) equal to 10:1, in practice, ten conductors will be used as conductors 8 and only one conductor 4.
FIGS. 16-29 illustrate various embodiments of a core 16, which in the embodiment illustrated in FIGS. 9, 10 and 11 forms the main part of the tubes 6 and 7. In versions of these embodiments, the tubes together with the magnetic field connectors 10 and 11 form the magnetisable body 1.
FIGS. 30 and 31 illustrate a magnetic field connector 10, 11 that can be used as a control field connector between the rectangular and square main cores 16 (illustrated in FIGS 10-11 and 20-22 respectively). This magnetic field connector comprises three parts 10′, 10″ and 19.
FIGS. 33-39 illustrate various embodiments of the magnetic field connector 10, 11, which are based on the fact that the connecting surfaces 14′ of the magnetic field connector 10, 11 are at the same angle as the end surfaces 14 as the core part 16.
In FIG. 36a an embodiment of the invention is illustrated with an assembly of magnetic field connectors 10, 11 and core parts 16. FIG. 36b illustrates the same embodiment viewed from the side.
FIGS. 37 and 38 are a sectional illustration and a view respectively illustrating a third embodiment of a magnetically influenced voltage connector device according to the invention. The device comprises (see FIG. 37b) a magnetisable body l comprising an external tube 20 and an internal tube 21 (or core parts 16, 16′) that are concentric and made of a magnetisable material. A gap 22 exists between the external tube's 20 inner wall and the internal tube's 21 outer wall. Magnetic field connectors 10, 11 conducting the tubes 20 and 21 are mounted at respective ends thereof (FIG. 37a). A compartment 23 (FIG. 37a) is placed in the gap 22 to keep the tubes 20, 21 concentric. A primary winding 4 composed of conductors 9 is wound round the internal tube 21 and is located in the gap 22. The winding axis A2 for the primary winding 4 therefore coincides with the axis A1 of the tubes 20 and 21. An electrical current-carrying or secondary winding 2 composed of the current conductor 8 is passed through the internal tube 21 along the outside of the external tube 20 N1 number of times, where N1=1, . . . r. With the primary winding 4 cooperating with the secondary winding 2 or the current-carrying conductor 8, an easily constructed, but efficient magnetically influenced transformer or switch results. An electrical current-carrying or control winding 3 composed of the current conductor 8′ is passed through the internal tube 21 and along the outside of the external tube 20 a quantity of N1 times, where N1=1, . . . , r. This embodiment of the device can also be modified so that the tubes 20, 21 do not have a round cross section but include a cross section that is selected from the group of shapes consisting of square, rectangular, triangular, etc.
FIGS. 39-41 illustrate different embodiments of the magnetic field connector 10, 11, which are specially adapted for the last-mentioned embodiment of the invention, i.e. that described in connection with FIGS. 37 and 38.
FIG. 39a is a sectional view and FIG. 39b a view from above of a magnetic field connector 10, 11 with connecting surfaces 14′ at an angle relative to the axis of the tubes 20, 21 (the core parts 16) and naturally the internal 21 and external 20 tubes will also be at the same angle to the connecting surfaces 14.
In operation, Vp (represented at the transformer terminals as VP1 and VP2, which is the AC voltage common to the two primaries (PW, PW′), resets the cores S1 and S2 when there is no transformer connection to the secondary side because CW and CW′ are deactivated. During the first part of the positive phase of Vp, the control winding (CW) of the first transformer (T3) is activated and transformative connection to the secondary winding (SW) of the first transformer (T3) is obtained, i.e., generating voltage Vs1. Following the zero passage of the negative phase, the control winding of the second transformer (T4) is activated by applying voltage Vk2 to it. The voltage Vs2 is generated voltage on the secondary winding (SW′)of the second transformer T4) and connected to the circuit. The rectification is obtained by connecting the primary winding of PW with the terminal 1 connected to L1 and terminal 2 connected to L2. The primary connection to PW′ is opposite the connection of PW; terminal 1′ is connected to L2 and terminal 2′ to L1, where L1 and L2 represent the terminals of an AC power source. The secondary windings (SW and SW′) are connected to the load in parallel to one another. At a first time, a pulsed control voltage Vk1 is applied in phase to Vp on PW. As a result, Vs1 is induced and appears on both the load and on SW′. SW′ is in high impedance mode and the current from SW is applied to the load. At the next zero crossing of the primary voltage Vp, Vk1 is removed and SW returns to high impedance., Vk2 is applied and again a voltage Vs2 appears on the load and on SW. In an alternative embodiment, Vk1 and Vk2 may be applied in phase and opposite to Vp. In yet another embodiment, Vk1 and Vk2 may be only substantially in phase with Vp.
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