EP0867061A1 - Power supply for non-linear loads - Google Patents
Power supply for non-linear loadsInfo
- Publication number
- EP0867061A1 EP0867061A1 EP96941260A EP96941260A EP0867061A1 EP 0867061 A1 EP0867061 A1 EP 0867061A1 EP 96941260 A EP96941260 A EP 96941260A EP 96941260 A EP96941260 A EP 96941260A EP 0867061 A1 EP0867061 A1 EP 0867061A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- zero
- inductor
- power supply
- phase
- core
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/16—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
Definitions
- the present invention relates to three-phase power supplies for non ⁇ linear loads, especially to such with lamp fittings for gas discharge tubes, like high pressure sodium lamps. Electric plants with a great number of fittings in parallel are used for example in green house cultivation and for road lighting.
- a discharge tube constitutes from an electrical point of view a non- linear element, which requires a current-limiting inductor in series, and which generates an approximately square wave load voltage, causing harmonic currents in the supply network.
- the inductor makes the current from the supply highly inductive, and for phase compensation a capacitor is usually connected in parallel to the inductor plus lamp. If this is not done, the fundamental compo ⁇ nent of the supply current can be more than twice as high, as when compensated, and the power losses in the network increase con ⁇ siderably.
- Inserting capacitors in a network may cause problems because of re ⁇ sonance phenomena between them and the inductance of the net-work, mainly originating from the supply transformer of the plant.
- Resonance implies amplification of harmonic currents and gives rise to increased losses in bars, cables and transformers.
- a typical supply voltage for a lamp fitting is 230 V, corresponding to the phase voltage of a 400 V system.
- the fittings are therefore usually connected between phase and neutral in a three-phase system.
- the dominating harmonic is the third, which has the property of hav ⁇ ing the same phase position in all phases. In other words, it appears as a zero-sequence current. It adds up in the neutral conductor, which therefore carries a three times as big third harmonic current as the phase conductors, and it appears as a circulating current in the primary delta winding of the supply transformer, causing losses and heating.
- the invention aims at a solution which in a simple, inexpensive and flexible way reduces the third harmonic current to a harmless level.
- Figure 1 shows a three-phase plant of current design
- Figure 2 an equivalent diagram
- Figure 3 an equivalent diagram of a plant according to one alternative of the invention
- Figure 4 to another alternative
- Figure 5 shows the zero- inductor in a preferred version
- Figure 6 a further developcment of the invention in a preferred version.
- Figure 1 shows a three-phase plan t wilh a ⁇ /Y-0 connected trans ⁇ former 1 having the loads 2 connected between phases and neutral.
- Figure 2 shows a simplified diagram for a group of lamp fittings, drawn as one fitting 2 per phase, with lamp 3, series inductor 4 and capacitor 5.
- Figure 3 shows one version of the zero-inductor 6. It has three essentially equal windings each of them connected in series with a phase coductor all magnetizing the core in the same direction. It is so dimensioned, that its impedance for the third harmonic, generated by the lamps, is high. In consequence the main part of this current finds its way through the phase-compensating capacitors and only a minor part flows through the network.
- the zero-inductor effectively impedes a third harmonic amplification caused by a resonance between capacitors and network impedance.
- the third harmonic voltage across a winding of the inductor is in the order of 10 V when the phase voltage is 230 V.
- Figure 4 shows a power system with the neutral conductor (N) threaded through the zero-inductor 6 forming a single-turn winding. It is dimensioned in the same way as above.
- the zero-inductor encircles the inductor without breaking it, which is desirable from a safety point of view.
- Figure 5 shows a similar system wi th the three phase conductors threaded through the zero-inductor. It is dimensioned using the same principles as outlined above and it functions in the same way.
- An advantage is, that it can be placed anywhere in the network independ ⁇ ently of if it is a 4- or 5-conductor system.
- the iron core of the zero-inductor has no air gap and can be a ring core made of oriented transformer iron. It is designed for a few volts of fundamental voltage. For higher voltages it will saturate, and then the zero-inductor only represents a low impedance. This design keeps down the size of the zero-inductor to a minimum and also ensures that no large voltage asymmetries appear, if the load current becomes asymmetrical, for example when a fuse breaks.
- Figure 6 shows a further development of the invention.
- the zero- inductor 6 is provided with one or more multi-turn windings 8 connected to circuits 7 comprising capacitors.
- circuits 7 comprising capacitors.
Landscapes
- Inverter Devices (AREA)
- Circuit Arrangements For Discharge Lamps (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9504342A SE515520C2 (sv) | 1995-12-05 | 1995-12-05 | Belysningsanläggning med nollföljdsström-induktor |
SE9504342 | 1995-12-05 | ||
PCT/SE1996/001539 WO1997021264A1 (en) | 1995-12-05 | 1996-11-26 | Power supply for non-linear loads |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0867061A1 true EP0867061A1 (en) | 1998-09-30 |
Family
ID=20400470
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96941260A Withdrawn EP0867061A1 (en) | 1995-12-05 | 1996-11-26 | Power supply for non-linear loads |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0867061A1 (sv) |
JP (1) | JP2000501878A (sv) |
AU (1) | AU1045397A (sv) |
SE (1) | SE515520C2 (sv) |
WO (1) | WO1997021264A1 (sv) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1999055124A1 (de) * | 1998-04-18 | 1999-10-28 | Manfred Diez | Verfahren zum betreiben eines gasentladungsstrahlers, und anordnung zur durchführung eines solchen verfahrens |
DE10225409B4 (de) * | 2002-06-07 | 2020-03-19 | Tdk Electronics Ag | Stromkompensierte Drossel und Schaltungsanordnung mit der stromkompensierten Drossel |
JP5033215B2 (ja) * | 2010-04-19 | 2012-09-26 | 株式会社因幡電機製作所 | 道路灯 |
DE102010044621A1 (de) * | 2010-09-02 | 2012-03-08 | Siemens Aktiengesellschaft | Vorrichtung zum Unterdrücken hochfrequenter Ströme in Zuleitungen eines Umrichters |
US11136985B2 (en) | 2018-08-31 | 2021-10-05 | Baker Hughes, A Ge Company, Llc | High frequency AC noise suppression within transformers |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1727834A (en) * | 1920-05-15 | 1929-09-10 | Bbc Brown Boveri & Cie | Rectifying system |
US4651266A (en) * | 1984-02-16 | 1987-03-17 | Fanuc Ltd | High-frequency noise absorbing circuit |
JPS6130917A (ja) * | 1984-07-19 | 1986-02-13 | 富士電気化学株式会社 | 3相4線式用ノイズフイルタ |
US5323304A (en) * | 1992-01-27 | 1994-06-21 | Georator Corporation | A.C. storage module for reducing harmonic distortion in an A.C. waveform |
DK58494A (da) * | 1994-01-21 | 1995-07-22 | Martin Hansen Nr | Fremgangsmåde til strømforsyning af et belysningsanlæg samt anvendelse heraf |
FI942447A0 (fi) * | 1994-05-26 | 1994-05-26 | Abb Stroemberg Kojeet Oy | Foerfarande foer eliminering av stoerningar i ett elkraftoeverfoeringsnaet samt koppling i ett elkraftoeverfoeringsnaet |
-
1995
- 1995-12-05 SE SE9504342A patent/SE515520C2/sv not_active IP Right Cessation
-
1996
- 1996-11-26 WO PCT/SE1996/001539 patent/WO1997021264A1/en not_active Application Discontinuation
- 1996-11-26 AU AU10453/97A patent/AU1045397A/en not_active Abandoned
- 1996-11-26 JP JP9521194A patent/JP2000501878A/ja active Pending
- 1996-11-26 EP EP96941260A patent/EP0867061A1/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO9721264A1 * |
Also Published As
Publication number | Publication date |
---|---|
SE515520C2 (sv) | 2001-08-20 |
JP2000501878A (ja) | 2000-02-15 |
SE9504342L (sv) | 1997-06-06 |
SE9504342D0 (sv) | 1995-12-05 |
WO1997021264A1 (en) | 1997-06-12 |
AU1045397A (en) | 1997-06-27 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19980616 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK FR GB LI NL |
|
RBV | Designated contracting states (corrected) |
Designated state(s): AT BE CH DE DK FR GB LI NL |
|
17Q | First examination report despatched |
Effective date: 20000210 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
18D | Application deemed to be withdrawn |
Effective date: 20000621 |