GB2514721A - Improvements relating to power adaptors - Google Patents
Improvements relating to power adaptors Download PDFInfo
- Publication number
- GB2514721A GB2514721A GB1416190.5A GB201416190A GB2514721A GB 2514721 A GB2514721 A GB 2514721A GB 201416190 A GB201416190 A GB 201416190A GB 2514721 A GB2514721 A GB 2514721A
- Authority
- GB
- United Kingdom
- Prior art keywords
- input
- power
- power adaptor
- drawn
- current waveform
- 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.)
- Granted
Links
- 239000007787 solid Substances 0.000 claims abstract description 9
- 239000003990 capacitor Substances 0.000 claims description 18
- 238000001914 filtration Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 3
- 230000001939 inductive effect Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
- H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
- H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
- H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
- H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
- H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/539—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
-
- 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
- H05B41/20—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 having no starting switch
- H05B41/23—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 having no starting switch for lamps not having an auxiliary starting electrode
- H05B41/232—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 having no starting switch for lamps not having an auxiliary starting electrode for low-pressure lamps
-
- 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
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters
- H05B41/282—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices
-
- 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
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters
- H05B41/295—Circuit arrangements in which the lamp is fed by power derived from DC by means of a converter, e.g. by high-voltage DC using static converters with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
-
- 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
- H05B41/36—Controlling
- H05B41/38—Controlling the intensity of light
- H05B41/39—Controlling the intensity of light continuously
- H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
- H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
- H05B41/3924—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by phase control, e.g. using a triac
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Circuit Arrangement For Electric Light Sources In General (AREA)
Abstract
A power adaptor 20 comprises an input 22 for connection to a mains supply, a filtering and rectifying circuit 30, and a resonant circuit 34, including a drive circuit (42, fig. 3), that provides an output 24 suitable for driving a load. A controller is adapted to determine the waveform of the current drawn from the input by the drive circuit, and to modify the current waveform that would inherently be drawn from the input by the drive circuit to reduce variation in instantaneous output power over each mains cycle. In particular from a sinusoidal wave to a square wave or inverted sinusoidal wave. The power adaptor may be suitable for driving a solid state light source, such as an LED, or a non-solid state light source, e.g. compact fluorescent lamp.
Description
Title -Improvements relating to Power Adaptors This invention relates to power adaptors, and in particular power supplies adapted for connection to a mains supply.
Power adaptors are devices adapted to receive power from a power supply, and convert that power into a form usable by a particular load. For many applications, the power adaptor requires large storage capacitors, such as electrolytic capacitors, at the output of the power adaptor, in order to provide a smooth transfer of power to the load. The inclusion of these large storage capacitors typically result in the power adaptors being bulky, and hence significantly increase the size of devices that include the power adaptor.
In addition, where the power adaptor is adapted for inclusion in a lighting circuit, the power adaptor often needs to function with a power supply including a TRIAC dimmer circuit. For this reason, conventional power adaptors for light sources, such as solid state light sources, discharge lamps and compact fluorescent lamps, include power factor correction circuits in order to increase the proportion of the mains half-cycle in which the current drawn by the light source is greater than the threshold level of the dimmer circuit.
There has now been devised an improved power adaptor, which overcomes or substantially mitigates the above-mentioned and/or other disadvantages
associated with the prior art.
According to the invention, there is provided a power adaptor comprising an input for connection to a mains supply, a drive circuit coupled to the input that provides an output suitable for driving a load, and a controller adapted to determine the waveform of the current drawn from the input by the drive circuit, wherein the controller is adapted to modify the current waveform that would inherently be drawn from the input by the drive circuit to reduce variation in instantaneous output power over each mains cycle.
According to a further aspect of the invention, there is provided a power adaptor comprising an input for connection to a mains supply, and a drive circuit coupled to the input that provides an output suitable for driving a load, wherein the drive circuit is configured such that the waveform of the current drawn from the input by S the drive circuit is modified relative to a sinusoidal waveform, such that there is a reduction in the variation in instantaneous output power over each mains cycle, and wherein the drive circuit does not include an LCL series-parallel resonant circuit.
The power adaptor according to the invention is advantageous principally because the reduction in the variation in instantaneous output power over each mains cycle removes the need for large storage capacitors, such as electrolytic storage capacitors, at the output of the power supply. Furthermore, where the power adaptor is adapted for use in a lighting circuit, the reduction in the variation in instantaneous output power over each mains cycle may be adapted to maintain the power drawn by the light source above the threshold level of the dimmer circuit.
The current waveform drawn from the input is preferably modified by having an increased current in the regions of the zero-crossing points of the input voltage and/or a reduced current in the intermediate periods. The current waveform drawn from the input may be modified by having an increased gradient in the periods adjacent to the zero-crossing points of the input voltage. Alternatively, or in addition, the current waveform drawn from the input maybe modified by having intermediate periods between the zero-crossing points of the input voltage, in which the current waveform is either substantially constant, or a smooth curve with a local minimum.
The current waveform drawn from the input may have an approximately square-shape waveform. Most preferably, however, the current waveform drawn from the input has the approximate form of an inverted sinusoidal wave.
The instantaneous output power is preferably substantially constant over each mains cycle. This is preferably achieved without the use of large storage capacitors, such as electrolytic capacitors, at the output of the power adaptor.
S The invention is particularly advantageous where the power adaptor is suitable for driving a light source. For example, the power adaptor may be suitable for driving a solid state light source, such as one or more LEDs, or alternatively a non-solid state light source, such as a fluorescent lamp or a compact fluorescent lamp (CFL).
Where the power adaptor has a drive circuit including an LCL series-parallel resonant circuit and a controller adapted to modify the current waveform inherently drawn by the resonant circuit, as described above, the power adaptor is preferably configured substantially as described in UK patent no 2449616 in relation to power adaptors for solid-state light sources. By "LCL series-parallel resonant circuit" is meant a resonant circuit comprising a first inductor and a first capacitor in series, and a parallel load leg including a second inductor. The first inductor and first capacitor are preferably connected in series between two input terminals of the resonant circuit, and the resonant circuit preferably comprises a load leg connected in parallel across the first capacitor, wherein the load leg comprises the second inductor and an output for driving the load, which are connected in series.
In particular, the LCL resonant circuit preferably has input terminals and output terminals with a first inductor Li, connected from a first input terminal through a common point with second inductor L2, to a first output terminal, the second input terminal being directly connected to the second output terminal, and a capacitor Cl, connected between the common point between the two inductors and the direct connections between second terminals of input and output. The input terminals are preferably adapted to be driven from a high frequency inverter. Any of the first inductor, the first capacitor and the second inductor may comprise a single inductive or capacitive component or a combination of such components.
According to a further aspect of the invention, there is provided a lighting system comprising a power adaptor as described above, and a lighting unit including at least one light source.
S According to a further aspect of the invention, there is provided a lighting unit suitable for direct connection to a mains supply, the lighting unit comprising a power adaptor as described above and one or more light sources.
In presently preferred embodiments, the lighting system includes a dimmer circuit having a minimum operating current, and the lighting unit is suitable for direct connection to a mains supply including a dimmer circuit.
Preferred embodiments of the invention will now be described in greater detail, by way of illustration only, with reference to the accompanying drawings, in which Figure 1 is a schematic diagram of a lighting system according to the invention; Figure 2 is a schematic diagram of a power adaptor according to the invention that forms part of the lighting system of Figure 1; Figure 3 is a schematic diagram of a resonant circuit, including a resonance controller and a resonance drive circuit, that forms part of the power adaptor of Figure 2; Figure 4 is an alternative resonant circuit suitable for a power adaptor for a solid state light source; and Figure 5 illustrates a conventional sinusoidal current waveform that follows the voltage (Figure 5a), a square-shaped current waveform (Figure Sb) and a current waveform having the form of an inverted sinusoidal wave (Figure 5c).
Figure 1 shows a lighting system according to the invention. The lighting system is connected to a mains circuit including a mains supply L,N and a TRIAC dimmer circuit 10, and comprises a power adaptor 20 and a compact fluorescent lamp (CFL) 50. The power adaptor 20 is supplied with electrical power from the mains circuit, and is adapted to provide electrical power to the compact fluorescent lamp (CFL) 50.
Referring now to Figure 2, the power adaptor 20 comprises an input 22 for drawing electrical power from the mains circuit, and an output 24 for providing electrical power to the compact fluorescent lamp (CFL) 50. The power adaptor 20 includes a filtering and rectifying circuit 30 at the input 22, such that the AC voltage waveform drawn from the mains circuit is supplied to the remainder of the power adaptor circuitry as a full-wave rectified waveform (DC+).
The power adaptor 20 also includes a low power, auxiliary power supply 32, and a resonant circuit 34 including a resonance drive circuit 42, which is described in more detail below with reference to Figure 3. The low power, auxiliary power supply 32 provides a low power DC output (+V) for powering the integrated circuits of the resonance drive circuit 42. This provides a stable power supply to the integrated circuits of the power adaptor to ensure stable functioning of those circuits. It is noted that in other embodiments, the integrated circuits of the power adaptor are powered by connections to additional windings coupled to one of the inductors of the resonant circuit, and hence the auxiliary power supply 32 is omitted.
The resonant circuit 34, including the resonance drive circuit 42, is shown in Figure 3. The resonance drive circuit 42 includes a controller 44 adapted to control the output of the resonance drive circuit 42, as discussed in more detail below.
The resonant circuit 34 has the form of an LCL series-parallel resonant circuit (Li, Cl and L2). The resonance drive circuit 42 is adapted to drive the LCL series-parallel resonant circuit with a square wave driving signal. This square wave signal is generated by two electronic switches, eg FETs, connected to a first end of the resonant circuit, which are controlled by the controller 44. The capacitors C2 and 03 create a connection point for the second end of the resonant circuit, substantially midway in voltage between DC+ and OV.
The LCL series-parallel resonant circuit is configured substantially as described in UK patent no 2449616 in relation to power adaptors for solid-state light sources.
In this configuration, the LCL series-parallel resonant circuit would inherently draw an approximately square-shaped current waveform from the input, as shown in Figure 5b. However, in order to reduce variation in instantaneous output power over each mains cycle, the controller 44 of the resonance drive circuit 42 is adapted to modify the current waveform that would inherently be drawn from the input by the resonant circuit. In particular, the controller is adapted to cause the current waveform to have the form of an inverted sinusoidal wave, as shown in Figure Sc. This results in a reduction in the variation in instantaneous output power over each mains cycle, and hence removes the need for large storage capacitors, such as electrolytic storage capacitors, at the output of the power supply. Furthermore, the reduction in the variation in instantaneous output power over each mains cycle facilitates maintaining the power drawn by the light source above the threshold level of the dimmer circuit.
Figure 4 shows an alternative resonant circuit suitable for a power adaptor for a solid state light source. This resonant circuit is similar to the resonant circuit shown in Figure 3, save for the replacement of the LCL series-parallel resonant circuit with an LC resonant circuit, and the provision of an output 150 suitable for driving a solid state light source. Furthermore, the resonance drive circuit 142 includes a controller 144. In order to reduce variation in instantaneous output power over each mains cycle, the controller 144 of the resonance drive circuit 142 is adapted to modify the current waveform that would inherently be drawn from the input by the resonant circuit. In particular, the controller is adapted to cause the current waveform to have either a square-shaped waveform, as shown in Figure 5b, of more preferably the form of an inverted sinusoidal wave, as shown in Figure 5c.
This current waveform provides the advantages discussed above in relation to the square waveform. In particular, the power adaptor is able to transfer power to the output more uniformly, and hence significantly reduce the size of, or even eliminate the need for, the capacitor (C5) required at the output.
Claims (7)
- Claims 1. A power adaptor comprising an input for connection to a mains supply, a drive circuit coupled to the input that provides an output suitable for driving a load, and a controller adapted to modify the waveform of the current that would inherently be drawn from the input by the drive circuit, wherein the controller modifies the current waveform by having an increased current in the regions of the zero-crossing points of the input voltage and/or a reduced current in the intermediate periods, thereby reducing variation in instantaneous output power over each mains cycle.
- 2. A power adaptor as claimed in Claim 1, wherein the current waveform drawn from the input is modified by having an increased gradient in the periods adjacent to the zero-crossing points of the input voltage.
- 3. A power adaptor as claimed in Claim 1 or Claim 2, wherein the current waveform drawn from the input is modified by having intermediate periods between the zero-crossing points of the input voltage, in which the current waveform is either substantially constant, or a smooth curve with a local minimum.
- 4. A power adaptor as claimed in any preceding claim, wherein the current waveform drawn from the input has the approximate form of an inverted sinusoidal wave.
- 5. A power adaptor as claimed in any preceding claim, wherein the instantaneous output power is substantially constant over each mains cycle.
- 6. A power adaptor as claimed in Claim 5, wherein the substantially constant instantaneous output power is achieved without the use of large storage capacitors, such as electrolytic capacitors.
- 7. A power adaptor as claimed in any preceding claim, wherein the power adaptor is suitable for driving a solid state light source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1416190.5A GB2514721B (en) | 2009-10-06 | 2009-10-06 | Improvements relating to power adaptors |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1416190.5A GB2514721B (en) | 2009-10-06 | 2009-10-06 | Improvements relating to power adaptors |
| GB0917434A GB2474833A (en) | 2009-10-06 | 2009-10-06 | Power adaptor having current waveform modification. |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB201416190D0 GB201416190D0 (en) | 2014-10-29 |
| GB2514721A true GB2514721A (en) | 2014-12-03 |
| GB2514721B GB2514721B (en) | 2015-02-25 |
Family
ID=41393872
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0917434A Withdrawn GB2474833A (en) | 2009-10-06 | 2009-10-06 | Power adaptor having current waveform modification. |
| GB1416190.5A Expired - Fee Related GB2514721B (en) | 2009-10-06 | 2009-10-06 | Improvements relating to power adaptors |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0917434A Withdrawn GB2474833A (en) | 2009-10-06 | 2009-10-06 | Power adaptor having current waveform modification. |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB2474833A (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040032223A1 (en) * | 2002-06-18 | 2004-02-19 | Henry George C. | Square wave drive system |
| GB2472038A (en) * | 2009-07-22 | 2011-01-26 | Holdip Ltd | Power adaptor for discharge light source |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4544863A (en) * | 1984-03-22 | 1985-10-01 | Ken Hashimoto | Power supply apparatus for fluorescent lamp |
| TW432900B (en) * | 1997-02-13 | 2001-05-01 | Koninkl Philips Electronics Nv | Circuit arrangement |
| US5994848A (en) * | 1997-04-10 | 1999-11-30 | Philips Electronics North America Corporation | Triac dimmable, single stage compact flourescent lamp |
-
2009
- 2009-10-06 GB GB0917434A patent/GB2474833A/en not_active Withdrawn
- 2009-10-06 GB GB1416190.5A patent/GB2514721B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040032223A1 (en) * | 2002-06-18 | 2004-02-19 | Henry George C. | Square wave drive system |
| GB2472038A (en) * | 2009-07-22 | 2011-01-26 | Holdip Ltd | Power adaptor for discharge light source |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201416190D0 (en) | 2014-10-29 |
| GB0917434D0 (en) | 2009-11-18 |
| GB2514721B (en) | 2015-02-25 |
| GB2474833A (en) | 2011-05-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) |
Free format text: REGISTERED BETWEEN 20200116 AND 20200122 |
|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20201006 |