WO1995033301A1 - Dispositif servant a convertir une tension alternative en tension de courant continu - Google Patents

Dispositif servant a convertir une tension alternative en tension de courant continu Download PDF

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Publication number
WO1995033301A1
WO1995033301A1 PCT/SE1995/000599 SE9500599W WO9533301A1 WO 1995033301 A1 WO1995033301 A1 WO 1995033301A1 SE 9500599 W SE9500599 W SE 9500599W WO 9533301 A1 WO9533301 A1 WO 9533301A1
Authority
WO
WIPO (PCT)
Prior art keywords
voltage
capacitor
diode
converter
switch
Prior art date
Application number
PCT/SE1995/000599
Other languages
English (en)
Inventor
Bengt Assow
Kjell Rolleberg
Original Assignee
Telefonaktiebolaget Lm Ericsson
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget Lm Ericsson filed Critical Telefonaktiebolaget Lm Ericsson
Priority to AU26343/95A priority Critical patent/AU2634395A/en
Publication of WO1995033301A1 publication Critical patent/WO1995033301A1/fr

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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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/10—Arrangements incorporating converting means for enabling loads to be operated at will from different kinds of power supplies, e.g. from ac or dc
    • 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
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

  • the present invention relates to a device for converting an alternating voltage to a direct current voltage, said device including a converter and a rectifier bridge across whose input the alternating voltage is applied.
  • a power supply unit which includes conventional peak rectification, where the rectifying and filtering circuit is comprised of a diode bridge in parallel with a capacitor, delivers a current output of short duration and a power factor which reaches to between 0.5 and 0.7.
  • the alternating voltage source is loaded over a time interval that extends from slightly before to slightly after the centre of each sinus half-wave.
  • the conduction time and therewith the power factor (i.e. the broad current consumption) of such power supply units can be increased in many different ways.
  • One method is to connect between the diode bridge and the capacitor a step up convert ⁇ er which includes a pulse controlled switching element, among other things, said step up converter functioning to provide from the voltage source a current which has the best possible sinus configuration, with the aid of pulse width control.
  • this method of procedure is complicated and causes the efficiency of the system to be lowered by several percentage units as a result of losses in the step up converter.
  • Another method uses a step down converter upstream of the converter.
  • This step-down converter functions to maintain the voltage to the converter constant, which can result in a simpler and more effective converter.
  • the converter input voltage is lowered considerably and all power must pass through the step down converter, which makes it difficult to obtain greater efficiency in this particular case.
  • Another method known to the art involves the inclusion of a choke in series with the converter.
  • a choke in order to achieve any appreciable increase in the power factor, it is necessary to use a choke of an unacceptable size.
  • the size of the choke can be made smaller by including a capacitor with which the choke may be in resonance, although the unit will then be highly frequency-sensitive and load-dependent.
  • U.S. Patent Specification No. 5,012,161 describes a power factor correction circuit which is used in an electronic ballast device for gas discharge lamps.
  • the electronic ballast device is said to include a diode bridge rectifier whose input is connected to an alternating voltage, and a diode in series with a capacitor is connected between the bridge output and the input of an electronic power circuit.
  • the electronic power circuit supplies one or more gas discharge lamps and keeps the capacitor charged at a given voltage level, by means of a transformer connected in series with a diode. In this way, voltage is supplied to the electronic power circuit by the diode bridge when the bridge output voltage is larger than the voltage level across the capacitor, and by the capacitor when the bridge output voltage is smaller than the voltage level across the capaci ⁇ tor.
  • DE-A1 4,243,943 describes an alternating current/direct current converter which includes, among other things, two series circuits connected in parallel between a diode bridge and a converter.
  • One series circuit includes a capacitor and a first diode and the other series circuit includes a second diode and a controlled switch.
  • a coil is connected between the interconnection point between the capacitor and the first diode in said one series circuit and the interconnection point between the second diode and the controlled switch in said other series circuit respectively.
  • US-A 5,146,399 describes a device which includes a converter and a diode bridge.
  • a first diode is coupled across the diode bridge output in parallel with a first controlled switch in series with a first coil which, in turn, is coupled in parallel with a capacitor in series with a second diode.
  • the converter input is connected to the interconnection point between the capacitor and the second diode by means of a second controlled switch.
  • This circuit delivers to the converter a voltage which consists in the absolute value of the voltage applied across the rectifying bridge plus a voltage stored across the capacitor (where the capacitor voltage may be zero) .
  • the object of the present invention is to provide a power supply unit for converting alternating voltage to DC-voltage, which will enable two mutually different voltage conversion functions to be combined readily and cheaply, therewith enabling the device to be used in a number of different electric networks on a worldwide basis.
  • This object is achieved with a device that includes a rectifier bridge on whose input an alternating voltage is applied and in which two series circuits are coupled in parallel across the input of the converter.
  • One series circuit includes a first capacitor and a first diode
  • the other series circuit includes a second diode and a controlled switch.
  • a coil is coupled between the interconnection point between the first capacitor and the first diode in said one series circuit and between the interconnection point between the second diode and the controlled switch in said other series circuit.
  • One output terminal of the rectifier bridge is connected to the interconnection point between the first diode and the controlled switch, while the other output terminal of said rectifier bridge is connected to a switch for selective connection of said bridge to the intercon- nection point between the first capacitor and the second diode or, alternatively, to the interconnection point between the first capacitor and the first diode.
  • the present invention When operating according to one of the voltage conversion functions, the present invention will provide a high power factor and satisfy the requirements placed on input current time variation and harmonic content for classification as a class A device in accordance with European Standard EN60555- 2.
  • Fig. 1 is a circuit diagram of a power supply unit according to one preferred embodiment of the invention.
  • Fig. 2a shows a positive half period of the input voltage and the input current of the power supply unit shown in Fig. 1 when its switch is in a position A, and also shows corre- sponding current input to a conventional power supply unit and the class areas according to European Standard EN555-2;
  • Fig. 2b shows a positive half period of the input voltage and the input current of the power supply unit shown in Fig. 1 when its switch is in a position B;
  • Fig. 3 shows two voltages as a function of the time measured in the power supply unit shown in Fig. 1 when the switch is in position A;
  • Fig. 4 illustrates voltages as a function of the time measured at the same locations as those in Fig. 3, but with the switch in position B.
  • the power supply unit converts alternating voltage to DC- voltage with an improved power factor which satisfies the requirement of power supply unit input current time variation for the unit to be classified as a class A-type apparatus in accordance with European Standard E555-2, and in one case maintains a high efficiency.
  • the preferred embodiment of the invention also enables switching between two different voltage states, for instance between 230 and 115 V, where one converter (for instance a fly back converter) in the power supply unit receives in both cases essentially the same DC- voltage when there is applied across the power supply unit in one voltage state an alternating voltage which is essen ⁇ tially twice as large as an alternating voltage that is applied in the second voltage state.
  • Fig. 1 illustrates a power supply unit according to the preferred embodiment of the invention.
  • the power supply unit includes a converter P2, which is preferably a fly back converter.
  • a load R L is connected across the output of the converter P2.
  • the power supply unit also includes a diode rectifying bridge Dl whose input is connected to an alternat ⁇ ing voltage source (mains voltage) V and a signal V in is obtained on the output of the bridge.
  • a series circuit and an auxiliary converter circuit PI (shown in broken lines) are connected between the output of the bridge Dl and the input of the converter P2.
  • the series circuit includes a first capacitor Cl and a first diode D2, while the auxiliary converter circuit PI includes a second diode D3 in series with a controlled switch T and a coil LI.
  • the coil LI is coupled between the connecting point or node 10 between the first capacitor Cl and the first diode D2 in the series circuit, and between the connecting node between the second diode D3 and the control switch T in the auxiliary converter circuit PI.
  • the series circuit and a second capacitor C2, the second diode D3 and the switch T are all coupled in parallel across the converter input, where an input voltage U C2 to the converter P2 is also shown.
  • One output terminal of the rectifier bridge Dl is connected to a connection node between the first diode D2 and the switch T, while the second output terminal is connected to a switch SWl which functions to connect the terminal selectively either to the node 10 or to the connecting node 12 between the first capacitor Cl and the second diode D3.
  • the nodes 10 and 12 correspond respectively to the two positions B and A of the switch SWl.
  • the switch SWl is shown in position A in the Figure.
  • the switch T is preferably a MOSFET-tran ⁇ istor and is controlled convention ⁇ ally by a control circuit 14, normally by a PWM control function, to either open or close the current circuit in which it is connected in the auxiliary converter circuit PI, this making or breaking of the current path being effected in response to the voltages detected in the nodes 10 and 12.
  • the control circuit 14 is also connected to the connecting node between the first diode D2 and the switch T.
  • the difference between the voltages in the nodes 10 and 12, which constitute the voltage across the first capacitor Cl, is also shown in the Figure as the voltage u Ci .
  • the auxiliary converter circuit PI forms a step down converter whose input is located at the output of the rectifier bridge Dl and whose output is located across the first capacitor Cl.
  • the auxiliary converter circuit PI forms a step up converter whose input is located at the output of the rectifier bridge Dl and whose output is located across the second capacitor C2.
  • the switch SWl is in position A, the unit according to the preferred embodiment is opera- tive at 230 V (European mains voltage), and in position B is operative at 115 V (American mains voltage).
  • Fig. 2a is a diagram which illustrates voltage/current as a function of time.
  • the diagram shows a half period of the input voltage V and the input current or the current I A taken from the mains to the inventive power supply unit .
  • the switch SWl in Fig. 1 is in position A, and also shows the time variation of a corresponding input current I ⁇ to a conventional power supply unit for the same input voltage and the same load R L .
  • the conventional power supply unit is comprised of a rectifier bridge and a converter, between which a large capacitor is coupled.
  • Fig. 2a also shows lines which are used in the division of the classification areas for classification of units in accordance with European Standard EN555-2.
  • the classification area is formed as follows: A straight line which is tangential to the maximum current output is drawn in a first interval of size ⁇ /3 around the maximum value of the input current. The remainder of the half-period is divided into a second and a third interval in which there are drawn straight lines that are parallel with the tangential line and which are located at a level which is 0.35 times the maximum current output. The lines at the different current levels are mutually connected at their common interval limits by means of straight lines extending at right angles thereto.
  • the current levels in the second and the third interval are connected to the time axis at the beginning and the end of the half-period.
  • the area that lies within these mutually connected lines is the classification area.
  • Fig. 2a shows the current output I ⁇ of the conventional power supply unit, falls completely within its classification area whose limits are referenced EN555-2 and are shown in full lines, and cannot therefore be classified as a class A unit, whereas when the switch SWl of the inventive power supply unit is in position A, the current output I x from the inventive power supply unit will lie within its classification area under less than 95% of the length of the half period, the limits of this area also being referenced EN555-2 but being shown in broken lines.
  • Fig. 2a also shows the conducting times of the two power supply units, and the input voltage levels 1, 2, 3 and 4 which control these conducting times.
  • the inventive unit conducts between the levels 1 and 2 on the input voltage curve, whereas the conventional unit conducts between the levels 3 and 4.
  • the inventive unit has a markedly longer conduction time (and therewith also a higher power factor) than the conventional unit.
  • the voltage levels 1 and 2 that control the conduction time of the inventive power supply unit will be explained in more detail below.
  • Fig. 3 shows the voltage U C2 as a function of the time when the switch SWl is in position A, together with the voltage V ln , which is a voltage of 230 V which coincides partly with the voltage U C2 and which is shown in broken lines when no such coincidence occurs.
  • Fig. 3 also shows a part of the voltage U C1 over this time period.
  • the function of the auxiliary converter circuit PI is to keep the capacitor Cl charged at a given voltage level U C1 .
  • the inventive device then functions to apply the voltage output V ln from the rectifier bridge Dl across the input of the converter P2 when this voltage V in is higher than the voltage U C1 across the capacitor Cl, and the voltage U ⁇ is applied across the input of the converter P2 when the voltage V ln is lower than the voltage U Ci .
  • the voltage U C2 is comprised of two different contributions, partly the contribution consisting of sinus wave peaks from the voltage V ln which extends from point 1 to point 2 on the voltage curve U C2 , and partly by the essential ⁇ ly linear contribution from the voltage U C1 extending from point 2 to point 1 on the voltage curve U C2 .
  • the points 1 and 2 in Fig. 3 correspond to the points 1 and 2 in Fig. 2a.
  • the voltage U C2 slowly falls when comprised of the voltage U C1 . This is because the capacitor Cl is dis ⁇ charged to supply the converter P2 with voltage.
  • the circuit When the auxiliary converter circuit PI is coupled as a step down converter, the circuit will have a much smaller power output than the converter P2 and therewith causes a very small reduction in unit efficiency.
  • the circuit also charges the capacitor Cl gently when starting up the system, which normally requires the provision of separate circuits.
  • the voltage level U C1 to which the capacitor Cl is charged by the auxiliary converter circuit PI lies in a range of 1/4-1, preferably about 2/3 of the peak value of the output voltage V in of the rectifier bridge Dl. The higher the voltage level U cl across the capacitor Cl, the more the inventive power supply unit will operate as a conventional unit, as described with reference to Fig. 2a.
  • the input current I A can be made more uniform with less distortion, by allowing the auxiliary converter circuit PI to charge the capacitor Cl for a shorter time than the time over which the converter P2 operates.
  • the capacitor Cl is charged to about 2/3 of the maximum output voltage of the rectifier bridge Dl, there is obtained a unit power factor of about 0.92-0.95.
  • Fig. 2b shows a diagram of input voltage V and input current I A to the inventive power supply unit from the mains supply when the switch SWl is in position B.
  • the form of this current output I A also satisfies European Standard EN555-2, even though this classification area is not shown in the Figure.
  • EN555-2 European Standard EN555-2
  • Fig. 4 shows voltage curves that correspond to the voltage curves shown in Fig. 3 for the inventive device, but with the switch SWl in position B.
  • the Figure shows the voltage U C2 as a function of time, together with the voltage V ln , which is a rectified voltage of 115 V.
  • the Figure also shows the voltage U C1 as the difference between V IN and U C2 .
  • the auxiliary converter circuit PI which now functions as a step up converter, charges the first capacitor Cl to the voltage level U cl , this voltage lying in the range of 75-300 V and being preferably about 200 V.
  • the voltage U Ci is preferably the same for both switching positions A and B.
  • the auxiliary converter PI charges the capacitor Cl over the full period and delivers, at the same time, the output voltage U C2 which is applied across the input of the converter P2.
  • the voltage U C1 across the capacitor Cl falls in series with the output voltage V in from the rectifier bridge Dl, meaning that the converter input voltage U c2 will be the sum of the output voltage V ln of the rectifier bridge Dl and the voltage U cl across the capacitor Cl.
  • the auxiliary converter circuit PI is more active when the switch SWl is in position B than when the switch was in position A, and the power output of the auxiliary converter circuit PI is about 2/3 of the converter power output.
  • the main function of the second capacitor C2 is to compensate for ripple currents and to filter out frequencies caused by the switch T.
  • the capacitor Cl has a much higher capacitance than the capacitor C2, the capacitance of capacitor Cl being at least 50 ⁇ F, preferably 200 ⁇ F, and at least 10 times, preferably 100 times, greater than the capacitance of the capacitor C2.

Abstract

Dans un dispositif servant à convertir une tension alternative (V) en tension de courant continu et comprenant un pont redresseur (D1) et un convertisseur (P2), deux circuits en série sont couplés en parallèle à l'entrée du convertisseur (P2). Un de ces circuits en série comprend un premier condensateur (C1) et une première diode (D2) et l'autre circuit comprend une deuxième diode (D3) et un commutateur commandé (T). Une bobine (L1) est couplée entre le n÷ud de raccordement (10) situé entre le premier condensateur (C1) et la première diode (D2) dans l'un des circuits en série, ainsi qu'entre le n÷ud de raccordement situé entre la deuxième diode (D3) et le commutateur commandé (T) dans l'autre circuit en série. Une borne de sortie du pont redresseur (D1) est connectée au n÷ud de raccordement situé entre la première diode (D2) et le commutateur commandé (T), tandis que l'autre borne de sortie du pont redresseur (D1) est connectée à un commutateur (SW1) servant à connecter sélectivement la deuxième borne de raccordement au n÷ud de raccordement (12) situé entre le premier condensateur (C1) et la deuxième diode (D3) ou, dans un autre mode de réalisation, au n÷ud de raccordement (10) situé entre le premier condensateur (C1) et la premère diode (D2).
PCT/SE1995/000599 1994-05-31 1995-05-29 Dispositif servant a convertir une tension alternative en tension de courant continu WO1995033301A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU26343/95A AU2634395A (en) 1994-05-31 1995-05-29 A device for converting an alternating voltage to direct current voltage

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9401870-2 1994-05-31
SE9401870A SE9401870L (sv) 1994-05-31 1994-05-31 Anordning för omvandling av en växelspänning till likspänning

Publications (1)

Publication Number Publication Date
WO1995033301A1 true WO1995033301A1 (fr) 1995-12-07

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1995/000599 WO1995033301A1 (fr) 1994-05-31 1995-05-29 Dispositif servant a convertir une tension alternative en tension de courant continu

Country Status (3)

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AU (1) AU2634395A (fr)
SE (1) SE9401870L (fr)
WO (1) WO1995033301A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19605493A1 (de) * 1995-02-15 1996-08-29 Matsushita Electric Works Ltd Spannungsversorgungsvorrichtung
EP0785611A2 (fr) * 1996-01-12 1997-07-23 Canon Kabushiki Kaisha Appareil d'alimentation de puissance électrique
ES2180357A1 (es) * 1999-06-25 2003-02-01 Univ Madrid Politecnica Convertidores de energia electrica alterna-continua.

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4109307A (en) * 1977-05-04 1978-08-22 Gte Sylvania Incorporated High power factor conversion circuitry
US5012161A (en) * 1989-01-05 1991-04-30 General Electric Company Power factor correction circuit
US5146399A (en) * 1989-08-14 1992-09-08 Jeff Gucyski Switching power apparatus having high factor and comprising pair of converter for obtaining fixed or variable output voltage
DE4243943A1 (en) * 1991-12-27 1993-07-01 Toko Inc AC rectifier including voltage-dropping DC=DC converter - restricts duration of flow of DC from bridge rectifier into prim. winding of transistor-switched transformer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4109307A (en) * 1977-05-04 1978-08-22 Gte Sylvania Incorporated High power factor conversion circuitry
US5012161A (en) * 1989-01-05 1991-04-30 General Electric Company Power factor correction circuit
US5146399A (en) * 1989-08-14 1992-09-08 Jeff Gucyski Switching power apparatus having high factor and comprising pair of converter for obtaining fixed or variable output voltage
DE4243943A1 (en) * 1991-12-27 1993-07-01 Toko Inc AC rectifier including voltage-dropping DC=DC converter - restricts duration of flow of DC from bridge rectifier into prim. winding of transistor-switched transformer

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19605493A1 (de) * 1995-02-15 1996-08-29 Matsushita Electric Works Ltd Spannungsversorgungsvorrichtung
DE19605493B4 (de) * 1995-02-15 2005-01-27 Matsushita Electric Works, Ltd., Kadoma Spannungsversorgungsvorrichtung
EP0785611A2 (fr) * 1996-01-12 1997-07-23 Canon Kabushiki Kaisha Appareil d'alimentation de puissance électrique
EP0785611A3 (fr) * 1996-01-12 1999-11-10 Canon Kabushiki Kaisha Appareil d'alimentation de puissance électrique
ES2180357A1 (es) * 1999-06-25 2003-02-01 Univ Madrid Politecnica Convertidores de energia electrica alterna-continua.

Also Published As

Publication number Publication date
SE9401870D0 (sv) 1994-05-31
AU2634395A (en) 1995-12-21
SE9401870L (sv) 1995-12-01

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