Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
IMPROVED APPARATUS & METHOD IN RELATION TO VOLTAGE OPTIMIZATION
Document Type and Number:
WIPO Patent Application WO/2012/028839
Kind Code:
A2
Abstract:
A transformer based voltage optimization apparatus (201) configured for use as a component of an electrical circuit that comprises a load (202) comprises a first transformer arrangement (203) specifically configured with means to transform received electrical current supplied at a first alternating voltage (204) into electrical current at a second alternating voltage (205), the apparatus characterised in that it further comprises a second transformer arrangement (206) specifically configured with means (207) to reduce at least one frequency component of the received electrical current wherein the at least one frequency component constitutes a frequency of electrical noise.

Inventors:
MARDAPITTAS ALEX (GB)
Application Number:
PCT/GB2011/001205
Publication Date:
March 08, 2012
Filing Date:
August 11, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
EMSC UK LTD (GB)
MARDAPITTAS ALEX (GB)
International Classes:
H02M5/10
Domestic Patent References:
WO2006068495A22006-06-29
Foreign References:
US20070290670A12007-12-20
Attorney, Agent or Firm:
FRANKS & CO LIMITED et al. (Brightside Lane, Sheffield S9 2RX, GB)
Download PDF:
Claims:
Claims

1. A transformer based voltage optimization apparatus (201) configured for use as a component of an electrical circuit that comprises a load (202), said apparatus comprising: a first transformer arrangement (203) specifically configured with means to transform received electrical current supplied at a first alternating voltage (204) into electrical current at a second alternating voltage (205); said apparatus characterised by further comprising: a second transformer arrangement (206) specifically configured with means (207) to reduce at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of electrical noise.

2. A transformer based voltage optimization apparatus as claimed in claim

1 wherein said means to transform said received electrical current of said first transformer arrangement comprises a core (208), said core having a primary winding (209) and a secondary winding (210).

3. A transformer based voltage optimization apparatus as claimed in claim

2 wherein an electrically insulated screen is positioned between said primary winding and said secondary winding.

4. A transformer based voltage optimization apparatus as claimed in claim 2 or claim 3 wherein said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is lower than said first alternating voltage.

5. A transformer based voltage optimization apparatus as claimed in any of claims 2 to 4 wherein said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is higher than said first alternating voltage.

6. A transformer based voltage optimization apparatus as claimed in any of claims 1 to 5 wherein said first transformer arrangement comprises a buck- boost transformer. 7. A transformer based voltage optimization apparatus as claimed in any of claims 2 to 6 wherein said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current comprises a third winding. 8. A transformer based voltage optimization apparatus as claimed in claim

7 wherein said third winding is formed about said core that is associated with said primary and said secondary windings.

9. A transformer based voltage optimization apparatus as claimed in claim 7 wherein said third winding is formed about a second core, said second core separate from said core that is associated with said primary and said secondary windings.

10. A transformer based voltage optimization apparatus as claimed in claim 9 wherein said second transformer arrangement is configured as a stand alone unit.

11. A transformer based voltage optimization apparatus as claimed in claim 9 or claim 10 wherein: said first transformer arrangement comprises a protective casing that houses said means to transform said received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; and said second transformer arrangement is housed outside said protective casing.

12. A transformer based voltage optimization apparatus as claimed in any preceding claim wherein said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is configured to reduce a plurality of frequency components of said received electrical current.

13. A transformer based voltage optimization apparatus as claimed in any preceding claim wherein said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is further configured such that said at least one frequency component is predetermined. 14. A transformer based voltage optimization apparatus as claimed in any preceding claim wherein said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is adjustable in order to facilitate selection of said at least one frequency to be reduced.

15. A transformer based voltage optimization apparatus as claimed in any preceding claim wherein said second transformer arrangement comprises a zero sequence harmonic winding. 16. A transformer based voltage optimization apparatus as claimed in any preceding claim wherein said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is, with respect to the supply frequency, configured to reduce a harmonic frequency component of said received electrical current.

17. A transformer based voltage optimization apparatus as claimed in any preceding claim wherein said second transformer arrangement is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

18. A transformer based voltage optimization apparatus as claimed in claim 17 wherein said phase shifting process is configured to split said received electrical current into a first output current and a second output current such that each said output current is out of phase with the other.

19. A transformer based voltage optimization apparatus as claimed in claim 17 or claim 18 wherein said respective output currents are, with respect to each other, phase shifted by 180° in order to thereby cancel each other out.

20. In relation to transforming received electrical power, a method of reducing electrical noise in the output electrical power, said method characterised by comprising the steps of: transforming a received electrical current supplied at a first alternating voltage (204) into electrical current at a second alternating voltage (205); and specifically reducing at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of said electrical noise.

21. The method as claimed in claim 20 wherein said step of transforming said received electrical current is performed by a first transformer arrangement comprising a core, said core having a primary winding and a secondary winding.

22. The method as claimed in claim 21 wherein said primary winding and said secondary winding are electrically insulated from one another.

23. The method as claimed in claim 21 or claim 22 wherein said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is lower than said first alternating voltage.

24. The method as claimed in any of claims 21 , 22 or 23 wherein said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is higher than said first alternating voltage.

25. The method as claimed as claimed in any of claims 20 to 24 wherein said first transformer arrangement comprises a buck-boost transformer. 26. The method as claimed in any of claims 21 to 25 wherein said step of specifically reducing at least one frequency component of said received electrical current is performed by a third winding.

27. The method as claimed in claim 26 wherein said third winding is formed about said core that is associated with said primary and said secondary windings.

28. The method as claimed in claim 26 wherein said third winding is formed about a second core, said second core separate from said core that is associated with said primary and said secondary windings.

29. The method as claimed in claim 28 wherein said second core and said third winding are configured as part of a stand alone unit.

30. The method as claimed in as claimed in 28 or claim 29 wherein said step of transforming said received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage is performed in a separately housed unit to said step of specifically reducing said at least one frequency component of said received electrical current, said separately housed unit comprising a protective casing.

31. The method as claimed in any of claims 20 to 30 wherein said step of specifically reducing said at least one frequency component of said received electrical current reduces a plurality of frequency components of said received electrical current.

32. The method as claimed as claimed in any of claims 20 to 31 wherein said step of specifically reducing said at least one frequency component of said received electrical current reduces a frequency component that is predetermined.

33. The method as claimed in any of claims 20 to 32 wherein said step of specifically reducing said at least one frequency component of said received electrical current comprises the further step of adjustably selecting said at least one frequency to be reduced.

34. The method as claimed in any of claims 20 to 33 wherein said step of specifically reducing said at least one frequency component of said received electrical current comprises use of a transformer arrangement having a zero sequence harmonic winding.

35. The method as claimed in any of claims 20 to 34 wherein said step of specifically reducing said at least one frequency component of said received electrical current that constitutes a frequency of said electrical noise comprises, with respect to the supply frequency, reducing a harmonic frequency component of said received electrical current.

36. The method as claimed in any of claims 20 to 35 wherein said step of specifically reducing said least one frequency component of said received electrical current that constitutes a frequency of said electrical noise comprises adjusting the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

37. The method as claimed in claim 36 wherein said phase shifting process splits said received electrical current into a first output current and a second output current such that each said output current is out of phase with the other.

38. The method as claimed in claim 36 or claim 37 wherein said respective output currents are, with respect to each other, phase shifted by 180° in order to thereby cancel each other out.

39. A transformer based voltage optimization apparatus (201) configured for use as a component of an electrical circuit that comprises a load, said apparatus comprising: a first transformer arrangement specifically configured with means to transform received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage, said means to transform said received electrical current comprising a core, said core having a primary winding and a secondary winding, said apparatus characterised by further comprising: a second transformer arrangement specifically configured with means to reduce at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of electrical noise that substantially comprises a harmonic frequency of said received electrical current, said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current comprising a third winding that is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

40. In relation to transforming received electrical power, a method of reducing electrical noise in the output electrical power, said method characterised by comprising the steps of: transforming a received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; and specifically reducing at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of said electrical noise, said at least one frequency substantially comprising a harmonic frequency of said received electrical current, wherein said step of specifically reducing said at least one harmonic frequency component comprises the step of adjusting the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

41. A transformer based voltage optimization apparatus (201) configured for use as a component of an electrical circuit that comprises a load, said apparatus comprising: a first transformer arrangement specifically configured with means to transform received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage, said means to transform said received electrical current comprising a core, said core having a primary winding and a secondary winding, said apparatus characterised by further comprising: a second transformer arrangement specifically configured with means to reduce at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of electrical noise that substantially comprises a harmonic frequency of said received electrical current, said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current comprising a zero sequence harmonic winding that is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

42. In relation to transforming received electrical power, a method of reducing electrical noise in the output electrical power, said method characterised by comprising the steps of: transforming a received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; and specifically reducing at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of said electrical noise, said at least one frequency substantially comprising a harmonic frequency of said received electrical current, wherein said step of specifically reducing said at least one harmonic frequency component utilises a zero sequence harmonic winding that is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

Description:
IMPROVED APPARATUS & METHOD IN RELATION TO VOLTAGE OPTIMIZATION

Field of the Invention

The present invention relates to an improved apparatus and method in relation to voltage optimization. More particularly, but not exclusively, the invention relates to voltage optimization in relation to domestic buildings, such as, for example, family homes. Background to the Invention

It is known to install in domestic and industrial premises of one kind or another one or more transformer based voltage optimization devices in order to improve efficiency in terms of the amount of electrical power consumed from a given power supply such as a mains power supply. Typically such a power supply will comprise supply of an alternating current (a.c).

The terminology "transformer based voltage optimization device" as used herein is to be interpreted as any device comprising a transformer that transforms a first alternating voltage to a second alternating voltage. The first alternating voltage may be lower than the second alternating voltage in which case the resultant voltage is thereby increased and said to be "stepped up". Similarly the first alternating voltage may be higher than the second alternating voltage in which case the resultant voltage is thereby decreased and said to be "stepped down". Furthermore, as those skilled in the art will understand, different terminology may be used in different countries as to what is meant by a "transformer based voltage optimization device". Thus, for example, in Japan the equivalent terminology is that of "voltage power optimization device". In the United States of America the terms "voltage reduction technology", "voltage reduction device", "voltage optimization technology" and "voltage optimization device" are all used and essentially relate to the same subject matter of a "transformer based voltage optimization device" as defined above. A transformer based voltage optimization device may be installed in a wide variety of situations wherein a power supply is required to provide power to a load of one sort or another. Thus, for example, a mains power supply is typically used to provide power to physical structures including, for example, permanent (fixed) buildings, temporary buildings and a variety of other installations requiring an electrical power supply in order to enable such installations to perform their function. Typically voltage optimization equipment comprising a device of the type referred to above comprises one or a plurality of transformers for stepping up and/or for stepping down (as required) the voltage in relation to particular load application(s) that is or are present in or otherwise associated with a given installation.

There are a variety of ways in which transformer based voltage optimization devices can optimize the voltage, by way of reduction, and provide energy savings. However only a few prior art designs of such transformer based voltage optimization devices or apparatus can actually provide high enough energy savings to make them into viable products.

A typical prior art voltage optimization device may operate to reduce the voltage supplied to a given site to a level which is closely matched to the specified nominal voltage rather than the voltage which is delivered to the site by the national grid. Optimizing the voltage allows all the equipment on site to operate at its designed (optimum) voltage and hence maximum efficiency is then achieved. Differing types of electrical load react differently to voltage optimization and hence some types of electrical load lend themselves to far greater savings than others. Furthermore, as those skilled in the art will appreciate, the national grid tends to keep supply of voltages highest near to the distribution level transformers so that customers connected to the far end of the supply are kept at a reasonable voltage in view of the effect of the voltage drop across the cable network. A current approach as is used by various companies that manufacture voltage optimization equipment is to select a specific design. A popular design so selected is known as a "buck-boost" transformer. This type of transformer design is well known and has existed in the public domain for many years. However, the application of buck-boost transformer technology for the sole purpose of energy savings is relatively new.

As those skilled in the art will understand a buck-boost transformer is a single phase distribution transformer wound with typically 120, 240 or 480 Volts primary windings with isolated secondary windings typically 12, 16, 24, 36 or 48 Volts. As designed and wound, the buck-boost transformer is an isolating transformer with electrical separation between primary and secondary windings. However, the connection to operate as a buck-boost transformer requires that the secondary is connected to the feed side of the primary winding hence eliminating the electrical separation.

Depending upon the connection between the primary and secondary windings, the unit can be used to buck (reduce) or boost (increase) the Line Voltage by a small percentage (typically 10%). As those skilled in the art will be aware, common applications of the buck-boost transformer include powering motors which are wound for higher voltage than supply or stepping up line voltages to adjust for transmission losses and voltage drops across a wiring network. Although buck-boost voltage optimization units are single phase units they are commonly wound onto a common iron core and used to operate on three phase electrical power supplies. The connection between primary and secondary windings means that the unit effectively becomes an auto-transformer and hence it cannot be used for isolation purposes. Buck-boost units are used for energy optimization type applications in domestic and industrial circumstances because they tend to be smaller, lighter, and cheaper to produce than various other types of transformer. Furthermore buck-boost transformers are capable of handling kVa ratings between 5 to10 times of the rated kVa as an isolating transformer.

A circuit diagram of a typical buck-boost type transformer as is known to be used in voltage optimization applications is schematically illustrated in Fig. 1. In the example shown buck-boost transformer 101 is configured such that the primary and secondary windings are connected to step down the voltage of the electrical power supplied. Buck-boost transformer 101 comprises an iron core 102. In the example shown transformer 101 receives electrical power from a power supply, such as a high voltage ('HV') mains power supply generally indicated at 103. The incoming power supply 103 is received by transformer 101 by virtue of primary winding 104. In Fig. 1 primary winding 104 is shown as three windings 104a, 104b and 104c in view of the incoming power supply of the example being a three phase power supply. By the term "winding" it is meant a complete group of insulated conductors designed to produce a magnetic field or to be acted upon by a magnetic field. Thus, as is known to those skilled in the art, a winding may consist of a number of separate conductors connected together electrically at their ends or may consist of a single conductor that has been shaped to form a number of loops or turns. In the example shown input power supply 103 is of a higher voltage than the resulting voltage ('LV') 105 that is output from transformer 101 . The output voltage is associated with secondary winding 106 (schematically illustrated as respective windings 106a, 106b and 106c). In view of the power supply of the example being a three phase supply buck-boost transformer 101 the secondary winding '106' comprises respective windings 106a, 106b and 106c. Secondary winding '106' is configured to deliver electrical power to load 107.

Thus a common approach to voltage optimization as typically used by companies that specialize in the field is to use a buck-boost transformer based voltage optimization device. However such buck-boost type voltage optimization devices (and, for that matter, various other types of voltage optimization transformers) do not specifically take into account the ever increasing problem of electrical noise (harmonics). Thus as companies install more information technology related equipment and invest in more energy saving devices such as high frequency lighting, variable speed drives and other electronically controlled devices, the problem with harmonics (noise) is constantly increasing.

As those skilled in the art will appreciate harmonics are created from many different sources within an electrical system and can have detrimental effects upon performance, longevity and efficiency of the generating equipment, the distribution system and loads fed by the network. Modern technologies such as, for example, variable speed drives and high frequency lighting controls and switch mode power supplies, are known to be responsible for increased levels of harmonics. It is generally understood that in the not too distant future energy suppliers will start to charge or disconnect users who feed too higher level of harmonics back to the national grid as a direct result of operating these types of equipment.

Harmonics can be defined as electrical currents operating at multiples of the supply frequency of the electrical power supply. In the United Kingdom the supply frequency is 50Hz and thus a third harmonic current is defined as currents flowing at a frequency of 150Hz(3x50 Hz). Harmonics are detrimental in several ways such as poor power factor, motor failures and overloaded power transformers and supply networks. An electrical system or network will be designed to have sufficient capacity to power the loads supplied to it. Harmonics generated on the system will increase the overall load such that cables and transformers can be overloaded. Added to this increasing problem there is also the problem of the efficiency of many components that are fed from the system or network being adversely affected.

As those skilled in the art will appreciate there are only a few designs on the market that can actually provide high enough energy savings to make them into viable products. One such product is known as PowerStar ® as is manufactured and sold by the present applicant/employer of the inventors of the invention of concern in the present application.

The problem of harmonics currents as identified above is concerned with saving energy and is not to be confused with the more generally known problem of preventing introduction of harmonics into three-phase poly-wire power lines. A good example of a solution to the latter problem is disclosed in US patent application publication no. US2007/0290670 entitled "Device for reducing harmonics in three-phase poly-wire power lines" in the name of "Lee" as published on December 20, 2007. Thus US2007/0290670 concerns removal or suppression of zero-phase harmonics current such that one or more harmonics currents are thereby substantially not introduced into an electric power system. US application no. 2007/0290670 makes use of open-delta type transformers or Y-coupling transformers and has nothing as such to do with saving energy. In fact, in stark contrast to the problem of concern in the present application, the device disclosed in US2007/0290670 will actually consume additional energy as compared with a similar device that is not configured to reduce or prevent introduction of harmonics current to the power supply. In summary US2007/0290670 is for a completely different purpose to the problem addressed in the present application.

Reference is hereby also made to International patent application publication no. WO 2006/068495 in the name of "Johansen" as published on June 29, 2006. WO 2006/068495 is entitled "Booster". As seen at page 1 , lines 24-26, an object of WO 2006/068495 is the "reduction of harmonics in a three- phased voltage supply with voltage stabilization in the form of an autotransformer". Since the device disclosed in WO 2006/068495 depends on use of an "autotransformer" then an advantage is that it has only a single winding with two end terminals and is thus typically smaller, lighter and cheaper to construct and maintain as compared with various other types of transformers. However, as will be understood by those skilled in the art an autotransformer suffers from various disadvantages and in particular in view of the fact that autotransformer has only a single winding then safety can be an issue, particularly when using mains voltages. Thus it is desirable to attempt to reduce harmonics currents in a supply voltage using a transformer that has separate windings in order to isolate the primary winding from the secondary winding and therefore to enhance safety in relation to use of the transformer.

The problem of electrical noise (harmonics distortions) is an increasing problem. There is therefore a need to minimize or remove harmonics from electrical power supplies in order to enable all the electrical equipment (the 'load') on a given site to operate more efficiently whilst attempting to improve energy savings and the life expectancy of voltage optimization equipment. The latter objective is required to be achieved with a transformer that comprises separate windings in order to isolate the primary winding from the secondary winding so as to provide a device that has improved safety features as compared with known devices that are based on an "autotransformer".

Summary of the Invention

One object of the present invention is to provide a transformer based voltage optimization apparatus that provides enhanced energy savings compared with prior art devices.

Another object of the present invention is to provide a method of transforming a first voltage to a second voltage wherein energy savings are improved compared with prior art methods.

A further object of the present invention is to provide a transformer based voltage optimization apparatus that is configured to provide an output current that comprises a reduced amount of electrical noise in comparison to the electrical current as received from an electrical power supply.

Yet a further object of the present invention is to provide an apparatus and a method for transforming a first voltage to a second voltage wherein the second voltage is associated with a reduced degree of electrical noise as compared with the first voltage.

Yet a further object of the present invention is to provide a transformer based voltage optimization apparatus that is configured such that at least one frequency component of a received electrical current is reduced or suppressed in comparison to the electrical current that is output from the apparatus.

Yet a further object of the present invention is to provide a method of transforming a supplied electrical voltage into an output electrical voltage wherein at least one frequency component of the electrical current that is received is substantially or totally removed thereby creating an output electrical current that is free of or substantially free of said at least one frequency component. Yet a further object of the present invention is to provide a transformer based voltage optimization apparatus that comprises a transformer having a plurality of windings and means to reduce or suppress at least one frequency component of a received electrical current so as to provide an output current from the apparatus that comprises none or substantially less of said at least one frequency component and wherein the apparatus is configured for safe use with, in particular, a mains power supply.

According to a first aspect of the present invention, there is provided a transformer based voltage optimization apparatus configured for use as a component of an electrical circuit that comprises a load, said apparatus comprising: a first transformer arrangement specifically configured with means to transform received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; said apparatus characterised by further comprising: a second transformer arrangement specifically configured with means to reduce at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of electrical noise.

Preferably said means to transform said received electrical current of said first transformer arrangement comprises a core, said core having a primary winding and a secondary winding.

Preferably an electrically insulated screen is positioned between said primary winding and said secondary winding.

Preferably said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is lower than said first alternating voltage.

Preferably said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is higher than said first alternating voltage.

Preferably said first transformer arrangement comprises a buck-boost transformer. Preferably said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current comprises a third winding.

Preferably said third winding is formed about said core that is associated with said primary and said secondary windings. Preferably said third winding is formed about a second core, said second core separate from said core that is associated with said primary and said secondary windings. Preferably said second transformer arrangement is configured as a stand alone unit.

Preferably, in accordance with a preferred embodiment of the present invention: said first transformer arrangement comprises a protective casing that houses said means to transform said received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; and said second transformer arrangement is housed outside said protective casing.

Preferably said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is configured to reduce a plurality of frequency components of said received electrical current.

Preferably said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is further configured such that said at least one frequency component is predetermined.

Preferably said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is adjustable in order to facilitate selection of said at least one frequency to be reduced. Preferably said second transformer arrangement comprises a zero sequence harmonic winding.

Preferably said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current is, with respect to the supply frequency, configured to reduce a harmonic frequency component of said received electrical current.

Preferably said second transformer arrangement is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

Preferably said phase shifting process is configured to split said received electrical current into a first output current and a second output current such that each said output current is out of phase with the other.

Preferably said respective output currents are, with respect to each other, phase shifted by 180° in order to thereby cancel each other out. According to a second aspect of the present invention there is provided, in relation to transforming received electrical power, a method of reducing electrical noise in the output electrical power, said method characterised by comprising the steps of: transforming a received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; and specifically reducing at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of said electrical noise. Preferably said step of transforming said received electrical current is performed by a first transformer arrangement comprising a core, said core having a primary winding and a secondary winding. Preferably said primary winding and said secondary winding are electrically insulated from one another.

Preferably said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is lower than said first alternating voltage.

Preferably said primary winding and said secondary winding are connected or connectable such that said second alternating voltage is higher than said first alternating voltage.

Preferably said first transformer arrangement comprises a buck-boost transformer.

Preferably said step of specifically reducing at least one frequency component of said received electrical current is performed by a third winding.

Preferably said third winding is formed about said core that is associated with said primary and said secondary windings. More preferably said third winding is formed about a second core, said second core separate from said core that is associated with said primary and said secondary windings.

Preferably said second core and said third winding are configured as part of a stand alone unit. Preferably said step of transforming said received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage is performed in a separately housed unit to said step of specifically reducing said at least one frequency component of said received electrical current, said separately housed unit comprising a protective casing.

Preferably said step of specifically reducing said at least one frequency component of said received electrical current reduces a plurality of frequency components of said received electrical current.

Preferably said step of specifically reducing said at least one frequency component of said received electrical current reduces a frequency component that is predetermined. Preferably said step of specifically reducing said at least one frequency component of said received electrical current comprises the further step of adjustably selecting said at least one frequency to be reduced.

Preferably said step of specifically reducing said at least one frequency component of said received electrical current comprises use of a transformer arrangement having a zero sequence harmonic winding.

Preferably said step of specifically reducing said at least one frequency component of said received electrical current that constitutes a frequency of said electrical noise comprises, with respect to the supply frequency, reducing a harmonic frequency component of said received electrical current.

Preferably said step of specifically reducing said at least one frequency component of said received electrical current that constitutes a frequency of said electrical noise comprises adjusting the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process. Preferably said phase shifting process splits said received electrical current into a first output current and a second output current such that each said output current is out of phase with the other.

Preferably said respective output currents are, with respect to each other, phase shifted by 180° in order to thereby cancel each other out.

According to a third aspect of the pre3sent invention there is provided a transformer based voltage optimization apparatus (201) configured for use as a component of an electrical circuit that comprises a load, said apparatus comprising: a first transformer arrangement specifically configured with means to transform received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage, said means to transform said received electrical current comprising a core, said core having a primary winding and a secondary winding, said apparatus characterised by further comprising: a second transformer arrangement specifically configured with means to reduce at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of electrical noise that substantially comprises a harmonic frequency of said received electrical current, said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current comprising a third winding that is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process. According to a fourth aspect of the present invention there is provided, in relation to transforming received electrical power, a method of reducing electrical noise in the output electrical power, said method characterised by comprising the steps of: transforming a received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; and specifically reducing at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of said electrical noise, said at least one frequency substantially comprising a harmonic frequency of said received electrical current, wherein said step of specifically reducing said at least one harmonic frequency component comprises the step of adjusting the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

According to a fifth aspect of the present invention there is provided a transformer based voltage optimization apparatus (201 ) configured for use as a component of an electrical circuit that comprises a load, said apparatus comprising: a first transformer arrangement specifically configured with means to transform received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage, said means to transform said received electrical current comprising a core, said core having a primary winding and a secondary winding, said apparatus characterised by further comprising: a second transformer arrangement specifically configured with means to reduce at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of electrical noise that substantially comprises a harmonic frequency of said received electrical current, said means of said second transformer arrangement configured to reduce said at least one frequency component of said received electrical current comprising a zero sequence harmonic winding that is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

According to a sixth aspect of the present invention there is provided a in relation to transforming received electrical power, a method of reducing electrical noise in the output electrical power, said method characterised by comprising the steps of: transforming a received electrical current supplied at a first alternating voltage into electrical current at a second alternating voltage; and specifically reducing at least one frequency component of said received electrical current wherein said at least one frequency component constitutes a frequency of said electrical noise, said at least one frequency substantially comprising a harmonic frequency of said received electrical current, wherein said step of specifically reducing said at least one harmonic frequency component utilises a zero sequence harmonic winding that is configured to adjust the phase angle of said at least one frequency component of said received electrical current in accordance with a phase shifting process.

Brief Description of the Drawings

For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which:

Fig. 1 schematically illustrates, in the form of a circuit diagram, a typical prior art buck-boost type transformer as referred to in the earlier section entitled "Background to the Invention"; and

Fig. 2 schematically illustrates, in the form of a circuit diagram, a first transformer arrangement and a second transformer arrangement as are connected and configured in accordance with the present invention.

Detailed Description

There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description.

Fig. 2 schematically illustrates, in the form of a circuit diagram, the best mode contemplated by the inventors in relation to providing a transformer based voltage optimization device that overcomes the aforementioned problem of unwanted electrical noise. In view of further tests having been applied to the design as illustrated in Figure 2 it has been ascertained that, in comparison to known buck-boost transformer based voltage optimization devices, harmonics are reduced by up to around 90% and furthermore the improved device provides an additional 4-5% more energy savings. In the best mode contemplated a voltage optimization device as configured in accordance with the present invention comprises a first transformer arrangement in the form of a specially wound zero sequence winding in combination with a second transformer arrangement in the form of a buck-boost transformer. In the following description the terms "zero sequence winding" (HMW) and "harmonics mitigation winding" are used synonymously and are thus to be construed as having the same meaning. In accordance with Figure 2 a transformer based voltage optimization apparatus 201 as is configured in accordance with the present invention is schematically illustrated at 201. Apparatus 201 is configured for use as a component of an electrical circuit that comprises a load, the load generally indicated at 202. Apparatus 201 comprises a first transformer arrangement 203 associated with an iron core and that is specifically configured with means to transform received electrical current supplied at a first alternating voltage (generally indicated at 204 "HV") into electrical current at a second alternating voltage "LV" as is generally indicated at 205. In the example shown transformer arrangement 203 is configured such that the input voltage 204 is at a higher voltage "HV" than the output voltage at 205. In accordance with the present invention, a second transformer arrangement generally indicated at 206 is also provided, transformer arrangement 206 configured with means 207 to remove or at least reduce at least one frequency component of the received electrical current wherein the at least one frequency component constitutes a frequency of electrical noise. First transformer arrangement 203 preferably comprises a buck- boost transformer as configured for stepping down an input (first) alternating voltage. The second transformer arrangement, 206, preferably comprises a zero sequence winding type arrangement 207. Those skilled in the arts will appreciate that a zero sequence winding is otherwise known as a "zig-zag" winding which is a commonly used term for the description of a transformer that is wound for phase shifting. The "zig-zag" description comes from the standard drawings that are used for a star connected phase shifting transformer. The second transformer arrangement, generally indicated at 206, is specifically configured with means to reduce at least one frequency component of the received electrical current such that the at least one frequency component constitutes a frequency of electrical noise. In accordance with the best mode contemplated the means to reduce the at least one frequency preferably comprises a "zig-zag" winding such as that indicated at 207.

First transformer arrangement 203 comprises an iron core 208 and primary windings 209a, 209b and 209c each respectively associated with a respective conductor of the three phase power supply. Transformer arrangement 203 comprises a secondary winding arrangement 210a, 210b and 210c such that secondary winding 210a is associated with primary winding 209a, secondary winding 210b is associated with primary winding 209b and secondary winding 210c is associated with primary winding 209c. The output of transformer arrangement 203 is passed through zig-zag system 207 by respective conductor lines 211a, 211 b and 21 1c such that conductor line 21 1a is associated with load phase line 210a, conductor line 21 1b is associated with load phase conductor line 210b and conductor line 211c is associated with load phase line 210c. Zig- zag system 207 is configured such that each of its terminals are connected to the respective conductor lines 211a, 211b and 211c. Furthermore each respective conductor line 21 1a, 221 b and 21 1c comprises a line reactor or "fuse" as are respectively indicated at 212a, 212b and 212c. The zig-zag or "zero sequence winding" 206 is herein described as the

HMW (Harmonics Mitigation Winding). The HMW may be included as a third "tertiary" winding of core 208 of transformer arrangement 203. However from researching the matter it has been found that this creates increased levels of wasteful circulating currents within the core. This in turn reduces overall efficiency of the voltage optimization apparatus and also reduces the effect upon total harmonic distortions of current in the system. For this reason, in the best mode contemplated, the present invention is preferably configured such that the HMW is included as a separate unit within the main enclosure (housing) of transformer arrangement 203 or, preferably, as a separate unit that is installed next to transformer arrangement 203. As those skilled in the art will understand, in its own right transformer arrangement 203, in the form of a buck-boost transformer in the example shown, will, in itself, have a beneficial effect in relation to reducing harmonics although it is to be noted that it is not designed to act as a filter for the harmonics. The beneficial effect just described is due to the inductance of transformer arrangement 203 and this may be increased by virtue of inserting an electrically insulated screen between the primary and secondary windings. In other words inserting an electrically insulated screen between winding 209a and 210a and between winding 209b and winding 210b and between winding 209c and winding 210c.

In accordance with the present invention inclusion of the HMW greatly enhances the effect of reducing harmonics and the HMW may effectively be "tuned" or otherwise adjusted so as to provide the required benefits (reduced harmonic currents) at one or more harmonic frequencies that are typically encountered.

In the best mode contemplated, in accordance with the present invention, the preferred method of reducing or potentially eliminating harmonics comprises the technique of "phase shifting". Thus, in accordance with the best mode contemplated, the HMW uses a "phase shifting" process. In this way the electrical power supply is split into two separate outputs. Each output is out of phase with the other and creates the effect of cancellation. Thus, as those skilled in the art will thereby appreciate, the idea is to create an interference situation such that ideally the current pairs cancel each other out. To achieve total cancellation a 180° phase shift between the harmonic current pairs is required.

In view of the above those skilled in the art will appreciate that the examples given are for the purposes of illustration only. More generally the application relates to the use of two technologies in combination in order to create a single product that gives high energy savings through voltage optimization in combination with reduction of harmonic currents on a given system. Although buck-boost transformers and zig-zag transformers are independently known in the public domain their use as described in combination herein is, before the present invention, not otherwise known to the inventors and this combination has been found to provide significant benefits in relation to energy consumption and significant benefits in relation to reducing "carbon omissions".