WO2014111778A1 - Power converter for charging and feeding - Google Patents

Power converter for charging and feeding Download PDF

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Publication number
WO2014111778A1
WO2014111778A1 PCT/IB2013/061408 IB2013061408W WO2014111778A1 WO 2014111778 A1 WO2014111778 A1 WO 2014111778A1 IB 2013061408 W IB2013061408 W IB 2013061408W WO 2014111778 A1 WO2014111778 A1 WO 2014111778A1
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WO
WIPO (PCT)
Prior art keywords
circuit
power converter
light
solar
switch
Prior art date
Application number
PCT/IB2013/061408
Other languages
French (fr)
Inventor
Rakeshbabu PANGULOORI
Priya Ranjan MISHRA
Original Assignee
Koninklijke Philips N.V.
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 Koninklijke Philips N.V. filed Critical Koninklijke Philips N.V.
Publication of WO2014111778A1 publication Critical patent/WO2014111778A1/en

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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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac 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
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac 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
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac 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 with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1582—Buck-boost converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
    • 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
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]

Definitions

  • Examples of such a system are chargeable devices, solar devices, light devices and parts thereof.
  • US 2009 / 0027001 Al discloses a solar powered apparatus with two power converters here in the form of two DC-DC-converters.
  • One power converter is used for charging a battery via a solar panel, the other one power converter is used for feeding fluorescent light via the battery.
  • a power converter for coupling a source circuit to a solar circuit for charging the source circuit in a first mode of the power converter and for coupling the source circuit to a light circuit to be fed by the source circuit in a second mode of the power converter, the power converter comprising
  • first terminals to be coupled to a parallel connection of first and second branches, the first branch comprising the solar circuit, and the second branch comprising the light circuit,
  • control circuit for bringing the power converter into the first and second modes.
  • the power converter By bringing the power converter into the first mode for example at first moments in time and into the second mode for example at second moments in time different from the first moments in time, at the first moments in time such as for example from dawn till dusk the source circuit is charged, and at the second moments in time such as for example from dusk till dawn the light circuit is fed, via one and the same power converter.
  • An embodiment of the power converter is defined by the control circuit comprising a comparator for comparing a detection of a solar voltage signal produced by the solar circuit with a threshold value and comprising a switch controller for in response to at least a comparison result controlling one or more switches of the power converter.
  • the detection of (an amplitude or an average value or a root mean square value etc. of) the solar voltage signal produced by the solar circuit is a good indication for the kind of mode that is required.
  • the one or more switches of the power converter allow the power converter to be controlled in different ways.
  • An embodiment of the power converter is defined by the control circuit further comprising a light controller for in response to a detection of a light current signal flowing through the light circuit and/or a detection of a light voltage signal present across the light circuit controlling the light current signal via the switch controller.
  • the detection of the light current signal flowing through the light circuit and/or the detection of the light voltage signal present across the light circuit are good indications for controlling (an amplitude or an average value or a root mean square value etc. of) the light current signal.
  • An embodiment of the power converter is defined by the control circuit further comprising a charge controller for in response to a detection of a source current signal flowing in a direction of the source circuit and/or a detection of a source voltage signal present across the source circuit and/or the detection of the solar voltage signal controlling the charging of the source circuit via the switch controller.
  • the detection of (an amplitude or an average value or a root mean square value etc. of) the source current signal flowing in a direction of the source circuit and/or the detection of (an amplitude or an average value or a root mean square value etc. of) the source voltage signal present across the source circuit and/or the detection of (an amplitude or an average value or a root mean square value etc. of) the solar voltage signal are good indications for controlling (an amplitude or an average value or a root mean square value etc. of) of the source current / voltage signal and for controlling the charging process.
  • An embodiment of the power converter is defined by further comprising - a first switch with a reverse diode, a first main contact of the first switch being coupled to one of the first terminals,
  • An embodiment of the power converter is defined by the first switch, in the first mode, being switched on and off and the second switch, in the first mode, being switched off, and the first switch, in the second mode, being switched off and the second switch, in the second mode being switched on and off.
  • An embodiment of the power converter is defined by the first mode being a buck mode and the second mode being a boost mode.
  • the buck mode operates from the first terminals to the second terminals.
  • the boost mode operates from the second terminals to the first terminals.
  • An embodiment of the power converter is defined by the second branch comprising a parallel connection of the light circuit and a first capacitor.
  • the first capacitor may form part of the light circuit.
  • An embodiment of the power converter is defined by a maximum of an amplitude of the solar voltage signal being smaller than an amplitude of a light voltage signal present across the light circuit when the light circuit is producing light, the light circuit, when receiving the maximum of the amplitude of the solar voltage signal, drawing a negligible current signal.
  • a negligible current signal is at least ten times smaller than a light current signal flowing through the light circuit when the light circuit is producing light, preferably at least a hundred times smaller, further preferably a thousand times smaller etc.
  • other solutions than this may be introduced to prevent that the solar voltage signal present across the light circuit when the light circuit is not producing light results in a too large current signal flowing through the light circuit.
  • An embodiment of the power converter is defined by a maximum of an amplitude of the solar voltage signal being larger than an amplitude of a source voltage signal present across the source circuit when the source circuit is being charged or is feeding the light circuit.
  • the amplitude of the source voltage signal present across the source circuit when the source circuit is being charged or is feeding the light circuit will be smaller than the maximum of the amplitude of the solar voltage signal and than the light voltage signal when the light circuit is producing light.
  • the light circuit may comprise for example one or more light emitting diodes of whatever kind and in whatever combination, such as for example one or more strings.
  • a method for in a first mode of a power converter charging a source circuit via a solar circuit and for in a second mode of the power converter feeding a light circuit via the source circuit, the power converter comprising first terminals to be coupled to a parallel connection of first and second branches, the first branch comprising the solar circuit, and the second branch comprising the light circuit, and the power converter comprising second terminals to be coupled to the source circuit, the method comprising the step of
  • a power converter may have different modes.
  • a basic idea is that the power converter should couple a source circuit to a solar circuit for charging the source circuit in a first mode of the power converter and should couple the source circuit to a light circuit to be fed by the source circuit in a second mode of the power converter.
  • a problem to provide an improved power converter has been solved.
  • a further advantage could be that the improved power converter may show an increased number of control options and may be simple, low cost and robust.
  • Fig. 1 shows an embodiment of a power converter
  • Fig. 2 shows power-voltage characteristics of a solar circuit for different radiation levels
  • Fig. 3 shows current-voltage characteristics of a light circuit in the form of a string of light emitting diodes
  • the power converter 1-10 comprises first terminals 1, 2 to be coupled to a parallel connection of first and second branches.
  • the first branch comprises a solar circuit 21, and the second branch comprises a light circuit 31.
  • the power converter 1-10 comprises second terminals 3, 4 to be coupled to a source circuit 41.
  • the power converter 1-10 may further comprise, as an example, a first switch 5 with a reverse diode 6. A first main contact of the first switch 5 may be coupled to one of the first terminals 1.
  • the power converter 1-10 may further comprise, as an example, an inductor 7. A first main contact of the inductor 7 may be coupled to a second main contact of the first switch 5, and a second main contact of the inductor 7 may be coupled to one of the second terminals 3.
  • the power converter 1-10 may further comprise, as an example, a second switch 8 with a bypass diode 9. A first main contact of the second switch 8 may be coupled to the second main contact of the first switch 5, and a second main contact of the second switch 8 may be coupled to the other ones of the first and second terminals 2, 4 that may be coupled to ground or another reference potential.
  • the solar circuit 21 in the first branch may be coupled serially to a rectifier circuit 22 such as a diode, and the combination may be called a solar device 20.
  • the light circuit 31 in the second branch may be coupled in parallel to a first capacitor 32, and the combination may be called a light device 30.
  • the source circuit 41 such as a battery or a cell, may be coupled in parallel to a second capacitor 42, and the combination may be called a source device 40.
  • the first and second capacitors 32, 42 have an energy storing function and/or a signal smoothing function.
  • the control circuit 10 may comprise a comparator 11 for comparing a detection of a solar voltage signal produced by the solar circuit 21 with a threshold value.
  • the control circuit 10 may further comprise a switch controller 12 coupled to control contacts of the switches 5 and 8 for in response to at least a comparison result from the comparator 11 controlling one or more of these switches 5, 8 of the power converter 1-10.
  • the comparator 11 receives (information about) the solar voltage signal from a terminal of the solar circuit 21.
  • the threshold value may for example be one third of a maximum of an amplitude of the solar voltage signal.
  • the control of the switches 5, 8 may for example be pulse width modulation etc.
  • the control circuit 10 may further comprise a light controller 13 for in response to a detection of a light current signal flowing through the light circuit 31 and/or a detection of a light voltage signal present across the light circuit 31 controlling the light current signal via the switch controller 12. Thereto, the light controller 13 receives
  • the control circuit 10 may further comprise a charge controller 14 for in response to a detection of a source current signal flowing in a direction of the source circuit 41 and/or a detection of a source voltage signal present across the source circuit 41 and/or the detection of the solar voltage signal controlling the charging of the source circuit 41 via the switch controller 12.
  • the charge controller 14 receives (information about) the source current signal from a terminal of the source circuit 41 and/or receives (information about) the source voltage signal from the same or another terminal of the source circuit 41 and receives (information about) the solar voltage signal from a terminal of the solar circuit 21.
  • the control circuit 10 may further comprise a multiplexer 15 controlled by the comparator 11 for either transporting control info from the light controller 13 or from the charge controller 14 to the switch controller 12.
  • a multiplexer 15 controlled by the comparator 11 for either transporting control info from the light controller 13 or from the charge controller 14 to the switch controller 12.
  • Other solutions for selecting the control info are not to be excluded, such as selectors etc.
  • a maximum of an amplitude of the solar voltage signal such as for example 24 Volt or 36 Volt should be smaller than an amplitude of the light voltage signal, as present across the light circuit 31 when the light circuit 31 is producing light, such as for example 64 Volt or 72 Volt.
  • the light circuit 31, when receiving the maximum of the amplitude of the solar voltage signal should draw a negligible current signal of substantially zero milli-Ampere.
  • a maximum of an amplitude of the solar voltage signal such as for example 24 Volt or 36 Volt should be larger than an amplitude of a source voltage signal, as present across the source circuit 41 when the source circuit 41 is being charged (buck mode) or is feeding the light circuit 31 (boost mode), such as 12 Volt.
  • Other examples are not to be excluded.
  • first waveforms in a first mode (buck mode) of the power converter are shown.
  • A a solar voltage signal (at about 18 Volt)
  • B a voltage signal present between the first switch 5 and the inductor 7 (switching from about 0 Volt to about 18 Volt and back)
  • C a source voltage signal (at about 12 Volt)
  • D an inductor current signal flowing in a direction of the source circuit 41 (saw-tooth from about 260 milli- Ampere to about 360 milli-Ampere and back).
  • the source circuit 41 is charged via the solar circuit 21, for example from dawn till dusk, whereby the first switch 5 is switched on and off to get the buck performance.
  • FIG. 5 second waveforms in a second mode (boost mode) of the power converter are shown.
  • A a light voltage signal (at about 48 Volt) and a light current signal (of about 500 milli-Ampere)
  • B a voltage signal present between the first switch 5 and the inductor 7 (switching from about 0 Volt to about 50 Volt and back)
  • C a source voltage signal (at about 12 Volt)
  • D an inductor current signal flowing away from the source circuit 41 (saw-tooth from about - 1,96 Ampere to about - 2, 16 Ampere and back, the minus signs indicate the opposite direction compared to the Fig. 4).
  • the light circuit 31 is fed via the source circuit 41, for example from dusk till dawn, whereby the second switch 8 is switched on and off to get the boost performance.
  • the solar voltage signal as derived from the anode of the diode of the rectifier circuit 22 may alternatively be derived from the cathode of this diode, but in that case the light circuit 31 must be switched off before detecting the solar voltage signal, otherwise this solar voltage signal is no indication for the amount of light received via the solar circuit 21.
  • power converters 1-10 couple source circuits 41 to solar circuits 21 for charging the source circuits 41 in first modes and couple the source circuit 41 to light circuits 31 to be fed by the source circuits 41 in second modes.
  • the power converters 1-10 comprise first terminals 1, 2 to be coupled to parallel connections of the solar circuits 21 and the light circuits 31, second terminals 3, 4 to be coupled to the source circuits 41 and control circuits 10 for bringing the power converters 1-10 into the modes, and may further comprise first and second switches 5, 8 and inductors 7.
  • the control circuits 10 may comprise comparators 11, switch controllers 12, light controllers 13 and charge controllers 14.
  • First modes may be buck modes
  • second modes may be boost modes. Maxima of amplitudes of the solar voltage signals may be smaller than amplitudes of light voltage signals present across the light circuits 31 when producing light. When receiving the solar voltage signal, the light circuits 31 may draw negligible current signals.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

Power converters (1-10) couple source circuits (41) to solar circuits (21) for charging the source circuits (41) in first modes and couple the source circuit (41) to light circuits (31) to be fed by the source circuits (41) in second modes. The power converters (1- 0) comprise first terminals (1, 2) to be coupled to parallel connections of the solar circuits (21) and the light circuits (31), second terminals (3, 4) to be coupled to the source circuits (41) and control circuits (10) for bringing the power converters (1-10) into the modes, and may further comprise first and second switches (5, 8) and inductors (7). The control circuits (10) may comprise comparators (11), switch controllers (12), light controllers (13) and charge controllers (14). First modes may be buck modes, second modes may be boost modes. Maxima of amplitudes of the solar voltage signals may be smaller than amplitudes of light voltage signals present across the light circuits (31) when producing light. When receiving the solar voltage signal, the light circuits (31) may draw negligible current signals.

Description

Power converter for charging and feeding
FIELD OF THE INVENTION
The invention relates to a power converter for coupling a source circuit to a solar circuit and for coupling the source circuit to a light circuit. The invention further relates to a system comprising the power converter and further comprising the source circuit and/or the solar circuit and/or the light circuit, and to a method.
Examples of such a system are chargeable devices, solar devices, light devices and parts thereof.
BACKGROUND OF THE INVENTION
US 2009 / 0027001 Al discloses a solar powered apparatus with two power converters here in the form of two DC-DC-converters. One power converter is used for charging a battery via a solar panel, the other one power converter is used for feeding fluorescent light via the battery.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved power converter.
Further objects of the invention are to provide a system and a method.
According to a first aspect, a power converter is provided for coupling a source circuit to a solar circuit for charging the source circuit in a first mode of the power converter and for coupling the source circuit to a light circuit to be fed by the source circuit in a second mode of the power converter, the power converter comprising
first terminals to be coupled to a parallel connection of first and second branches, the first branch comprising the solar circuit, and the second branch comprising the light circuit,
second terminals to be coupled to the source circuit, and
a control circuit for bringing the power converter into the first and second modes.
One side of the power converter is to be connected to a source circuit, and another side of the power converter is to be connected a solar circuit and a light circuit. In a first mode of the power converter, the source circuit is charged by the solar circuit via the power converter, from the first terminals to the second terminals. In a second mode of the power converter, the light circuit is fed by the source circuit via the power converter, from the second terminals to the first terminals. Thereto, the first terminals of the power converter are to be coupled to a parallel connection of first and second branches, the first branch comprising the solar circuit, and the second branch comprising the light circuit, and the second terminals of the power converter are to be coupled to the source circuit. By bringing the power converter into the first mode for example at first moments in time and into the second mode for example at second moments in time different from the first moments in time, at the first moments in time such as for example from dawn till dusk the source circuit is charged, and at the second moments in time such as for example from dusk till dawn the light circuit is fed, via one and the same power converter.
As a result, an improved power converter has been created whereby, compared to US 2009 / 0027001 Al, one of the two prior art power converters can be omitted, and this is a great advantage.
An embodiment of the power converter is defined by the control circuit comprising a comparator for comparing a detection of a solar voltage signal produced by the solar circuit with a threshold value and comprising a switch controller for in response to at least a comparison result controlling one or more switches of the power converter. The detection of (an amplitude or an average value or a root mean square value etc. of) the solar voltage signal produced by the solar circuit is a good indication for the kind of mode that is required. The one or more switches of the power converter allow the power converter to be controlled in different ways.
An embodiment of the power converter is defined by the control circuit further comprising a light controller for in response to a detection of a light current signal flowing through the light circuit and/or a detection of a light voltage signal present across the light circuit controlling the light current signal via the switch controller. Preferably, the detection of the light current signal flowing through the light circuit and/or the detection of the light voltage signal present across the light circuit are good indications for controlling (an amplitude or an average value or a root mean square value etc. of) the light current signal.
An embodiment of the power converter is defined by the control circuit further comprising a charge controller for in response to a detection of a source current signal flowing in a direction of the source circuit and/or a detection of a source voltage signal present across the source circuit and/or the detection of the solar voltage signal controlling the charging of the source circuit via the switch controller. Preferably, the detection of (an amplitude or an average value or a root mean square value etc. of) the source current signal flowing in a direction of the source circuit and/or the detection of (an amplitude or an average value or a root mean square value etc. of) the source voltage signal present across the source circuit and/or the detection of (an amplitude or an average value or a root mean square value etc. of) the solar voltage signal are good indications for controlling (an amplitude or an average value or a root mean square value etc. of) of the source current / voltage signal and for controlling the charging process.
An embodiment of the power converter is defined by further comprising - a first switch with a reverse diode, a first main contact of the first switch being coupled to one of the first terminals,
an inductor, a first main contact of the inductor being coupled to a second main contact of the first switch, and a second main contact of the inductor being coupled to one of the second terminals, and
- a second switch with a bypass diode, a first main contact of the second switch being coupled to the second main contact of the first switch, and a second main contact of the second switch being coupled to the other ones of the first and second terminals.
This is a simple, low cost and robust embodiment, without having excluded other embodiments of the power converter.
An embodiment of the power converter is defined by the first switch, in the first mode, being switched on and off and the second switch, in the first mode, being switched off, and the first switch, in the second mode, being switched off and the second switch, in the second mode being switched on and off. This is a simple, low cost and robust embodiment, without having excluded other controls of the switches.
An embodiment of the power converter is defined by the respective first and second switches being synchronous rectifiers in the respective second and first modes. This synchronous operation improves the power efficiency of the power converter in both modes.
An embodiment of the power converter is defined by the first mode being a buck mode and the second mode being a boost mode. The buck mode operates from the first terminals to the second terminals. The boost mode operates from the second terminals to the first terminals.
An embodiment of the power converter is defined by the first branch comprising a serial connection of the solar circuit and a rectifier circuit. Alternatively, the rectifier circuit may form part of the solar circuit. Further alternatively, other solutions than the rectifier circuit may be introduced to prevent that the light voltage signal, as present across the light circuit when the light circuit is producing light, results in a too large current signal flowing through the solar circuit.
An embodiment of the power converter is defined by the second branch comprising a parallel connection of the light circuit and a first capacitor. Alternatively, the first capacitor may form part of the light circuit.
An embodiment of the power converter is defined by the source circuit comprising a second capacitor or a battery or a cell or comprising a battery or a cell coupled in parallel to a second capacitor. The battery and the cell may be any kind of type.
An embodiment of the power converter is defined by a maximum of an amplitude of the solar voltage signal being smaller than an amplitude of a light voltage signal present across the light circuit when the light circuit is producing light, the light circuit, when receiving the maximum of the amplitude of the solar voltage signal, drawing a negligible current signal. A negligible current signal is at least ten times smaller than a light current signal flowing through the light circuit when the light circuit is producing light, preferably at least a hundred times smaller, further preferably a thousand times smaller etc. Alternatively, other solutions than this may be introduced to prevent that the solar voltage signal present across the light circuit when the light circuit is not producing light results in a too large current signal flowing through the light circuit.
An embodiment of the power converter is defined by a maximum of an amplitude of the solar voltage signal being larger than an amplitude of a source voltage signal present across the source circuit when the source circuit is being charged or is feeding the light circuit. Usually, the amplitude of the source voltage signal present across the source circuit when the source circuit is being charged or is feeding the light circuit will be smaller than the maximum of the amplitude of the solar voltage signal and than the light voltage signal when the light circuit is producing light.
The light circuit may comprise for example one or more light emitting diodes of whatever kind and in whatever combination, such as for example one or more strings.
According to a second aspect, a system is provided comprising the power converter as defined above and further comprising the source circuit and/or the solar circuit and/or the light circuit.
According to a third aspect, a method is provided for in a first mode of a power converter charging a source circuit via a solar circuit and for in a second mode of the power converter feeding a light circuit via the source circuit, the power converter comprising first terminals to be coupled to a parallel connection of first and second branches, the first branch comprising the solar circuit, and the second branch comprising the light circuit, and the power converter comprising second terminals to be coupled to the source circuit, the method comprising the step of
- bringing the power converter into the first and second modes.
An insight is that a power converter may have different modes. A basic idea is that the power converter should couple a source circuit to a solar circuit for charging the source circuit in a first mode of the power converter and should couple the source circuit to a light circuit to be fed by the source circuit in a second mode of the power converter.
A problem to provide an improved power converter has been solved. A further advantage could be that the improved power converter may show an increased number of control options and may be simple, low cost and robust.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 shows an embodiment of a power converter,
Fig. 2 shows power-voltage characteristics of a solar circuit for different radiation levels,
Fig. 3 shows current-voltage characteristics of a light circuit in the form of a string of light emitting diodes,
Fig. 4 shows first waveforms in a first mode of the power converter, and Fig. 5 shows second waveforms in a second mode of the power converter.
DETAILED DESCRIPTION OF EMBODFMENTS
In the Fig. 1, an embodiment of a power converter 1-10 is shown. The power converter 1-10 comprises first terminals 1, 2 to be coupled to a parallel connection of first and second branches. The first branch comprises a solar circuit 21, and the second branch comprises a light circuit 31. The power converter 1-10 comprises second terminals 3, 4 to be coupled to a source circuit 41.
The power converter 1-10 may further comprise, as an example, a first switch 5 with a reverse diode 6. A first main contact of the first switch 5 may be coupled to one of the first terminals 1. The power converter 1-10 may further comprise, as an example, an inductor 7. A first main contact of the inductor 7 may be coupled to a second main contact of the first switch 5, and a second main contact of the inductor 7 may be coupled to one of the second terminals 3. The power converter 1-10 may further comprise, as an example, a second switch 8 with a bypass diode 9. A first main contact of the second switch 8 may be coupled to the second main contact of the first switch 5, and a second main contact of the second switch 8 may be coupled to the other ones of the first and second terminals 2, 4 that may be coupled to ground or another reference potential.
The solar circuit 21 in the first branch may be coupled serially to a rectifier circuit 22 such as a diode, and the combination may be called a solar device 20. The light circuit 31 in the second branch may be coupled in parallel to a first capacitor 32, and the combination may be called a light device 30. The source circuit 41, such as a battery or a cell, may be coupled in parallel to a second capacitor 42, and the combination may be called a source device 40. The first and second capacitors 32, 42 have an energy storing function and/or a signal smoothing function.
The power converter 1-10 couples the source circuit 41 to the solar circuit 21 for charging the source circuit 41 in a first mode of the power converter 1-10 and couples the source circuit 41 to the light circuit 31 to be fed by the source circuit 41 in a second mode of the power converter 1-10. Thereto, the power converter 1-10 comprises a control circuit 10 for bringing the power converter 1- 10 into the first and second modes.
The control circuit 10 may comprise a comparator 11 for comparing a detection of a solar voltage signal produced by the solar circuit 21 with a threshold value. The control circuit 10 may further comprise a switch controller 12 coupled to control contacts of the switches 5 and 8 for in response to at least a comparison result from the comparator 11 controlling one or more of these switches 5, 8 of the power converter 1-10. Thereto, the comparator 11 receives (information about) the solar voltage signal from a terminal of the solar circuit 21. The threshold value may for example be one third of a maximum of an amplitude of the solar voltage signal. The control of the switches 5, 8 may for example be pulse width modulation etc.
The control circuit 10 may further comprise a light controller 13 for in response to a detection of a light current signal flowing through the light circuit 31 and/or a detection of a light voltage signal present across the light circuit 31 controlling the light current signal via the switch controller 12. Thereto, the light controller 13 receives
(information about) the light current signal from a terminal of the light circuit 31 and/or receives (information about) the light voltage signal from the same or another terminal of the light circuit 31.
The control circuit 10 may further comprise a charge controller 14 for in response to a detection of a source current signal flowing in a direction of the source circuit 41 and/or a detection of a source voltage signal present across the source circuit 41 and/or the detection of the solar voltage signal controlling the charging of the source circuit 41 via the switch controller 12. Thereto, the charge controller 14 receives (information about) the source current signal from a terminal of the source circuit 41 and/or receives (information about) the source voltage signal from the same or another terminal of the source circuit 41 and receives (information about) the solar voltage signal from a terminal of the solar circuit 21.
The control circuit 10 may further comprise a multiplexer 15 controlled by the comparator 11 for either transporting control info from the light controller 13 or from the charge controller 14 to the switch controller 12. Other solutions for selecting the control info are not to be excluded, such as selectors etc.
For example, the first switch 5 is in the first mode being switched on and off, and the second switch 8 is then kept off (off = non-conducting, on = conducting), with its bypass diode 9 still being able to perform. Then, the first switch 5 is in the second mode kept off, with its reverse diode 6 still being able to perform, and the second switch 8 is then switched on and off. The first mode may be a buck mode and the second mode may be a boost mode.
In the Fig. 2, power-voltage characteristics of the solar circuit 21 for different radiation levels are shown (vertical axis power in Watt, horizontal axis voltage in Volt, from 0 Volt to 24 Volt or 36 Volt).
In the Fig. 3, current-voltage characteristics of a light circuit 31 in the form of a string of light emitting diodes are shown (vertical axis current in milli- Ampere, horizontal axis voltage in Volt, from 0 Volt to 80 Volt, clearly until 48 Volt this light circuit 31 is not drawing any current signal and is not consuming any power).
In view of the Fig. 2 and 3, as an example only, a maximum of an amplitude of the solar voltage signal such as for example 24 Volt or 36 Volt should be smaller than an amplitude of the light voltage signal, as present across the light circuit 31 when the light circuit 31 is producing light, such as for example 64 Volt or 72 Volt. The light circuit 31, when receiving the maximum of the amplitude of the solar voltage signal, should draw a negligible current signal of substantially zero milli-Ampere. Similarly, a maximum of an amplitude of the solar voltage signal such as for example 24 Volt or 36 Volt should be larger than an amplitude of a source voltage signal, as present across the source circuit 41 when the source circuit 41 is being charged (buck mode) or is feeding the light circuit 31 (boost mode), such as 12 Volt. Other examples are not to be excluded.
In the Fig. 4, first waveforms in a first mode (buck mode) of the power converter are shown. A = a solar voltage signal (at about 18 Volt), B = a voltage signal present between the first switch 5 and the inductor 7 (switching from about 0 Volt to about 18 Volt and back), C = a source voltage signal (at about 12 Volt), and D = an inductor current signal flowing in a direction of the source circuit 41 (saw-tooth from about 260 milli- Ampere to about 360 milli-Ampere and back). Here, the source circuit 41 is charged via the solar circuit 21, for example from dawn till dusk, whereby the first switch 5 is switched on and off to get the buck performance.
In the Fig. 5, second waveforms in a second mode (boost mode) of the power converter are shown. A = a light voltage signal (at about 48 Volt) and a light current signal (of about 500 milli-Ampere), B = a voltage signal present between the first switch 5 and the inductor 7 (switching from about 0 Volt to about 50 Volt and back), C = a source voltage signal (at about 12 Volt), and D = an inductor current signal flowing away from the source circuit 41 (saw-tooth from about - 1,96 Ampere to about - 2, 16 Ampere and back, the minus signs indicate the opposite direction compared to the Fig. 4). Here, the light circuit 31 is fed via the source circuit 41, for example from dusk till dawn, whereby the second switch 8 is switched on and off to get the boost performance.
Many alternatives will be possible. For example, in the power converter 1-10, more than two switches 5, 8 may be used, and the inductor 7 may get another location. For example, in the control circuit 10, two or more blocks may be combined, and each block may be divided into parts. Each block may be realized through hardware, software or a mixture of both. Each block may comprise a processor or may form part of a processor.
The solar voltage signal as derived from the anode of the diode of the rectifier circuit 22 may alternatively be derived from the cathode of this diode, but in that case the light circuit 31 must be switched off before detecting the solar voltage signal, otherwise this solar voltage signal is no indication for the amount of light received via the solar circuit 21.
In another embodiment, the respective first and second switches 5, 8 may be used as synchronous rectifiers during respective feeding and charging. In the first mode, the first switch 5 is used as a control switch and the second switch 8 is used as a synchronous rectifier to charge the source circuit 41. In the second mode, the second switch 8 is used as a control switch and the first switch 5 is used as a synchronous rectifier to feed the light circuit 31. The first and second switches 5, 8 are switched on complementary to each other with a sufficient amount of dead time in between. This synchronous operation will improve the power efficiency of the power converter 1-10 in both modes.
Summarizing, power converters 1-10 couple source circuits 41 to solar circuits 21 for charging the source circuits 41 in first modes and couple the source circuit 41 to light circuits 31 to be fed by the source circuits 41 in second modes. The power converters 1-10 comprise first terminals 1, 2 to be coupled to parallel connections of the solar circuits 21 and the light circuits 31, second terminals 3, 4 to be coupled to the source circuits 41 and control circuits 10 for bringing the power converters 1-10 into the modes, and may further comprise first and second switches 5, 8 and inductors 7. The control circuits 10 may comprise comparators 11, switch controllers 12, light controllers 13 and charge controllers 14. First modes may be buck modes, second modes may be boost modes. Maxima of amplitudes of the solar voltage signals may be smaller than amplitudes of light voltage signals present across the light circuits 31 when producing light. When receiving the solar voltage signal, the light circuits 31 may draw negligible current signals.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:
1. A power converter (1-10) for coupling a source circuit (41) to a solar circuit (21) for charging the source circuit (41) in a first mode of the power converter and for coupling the source circuit (41) to a light circuit (31) to be fed by the source circuit (41) in a second mode of the power converter, the power converter comprising
- first terminals (1, 2) to be coupled to a parallel connection of first and second branches, the first branch comprising the solar circuit (21), and the second branch comprising the light circuit (31),
second terminals (3, 4) to be coupled to the source circuit (41), and a control circuit (10) for bringing the power converter into the first and second modes.
2. The power converter as defined in claim 1, the control circuit (10) comprising a comparator (11) for comparing a detection of a solar voltage signal produced by the solar circuit (21) with a threshold value and comprising a switch controller (12) for in response to at least a comparison result controlling one or more switches of the power converter.
3. The power converter as defined in claim 2, the control circuit (10) further comprising a light controller (13) for in response to a detection of a light current signal flowing through the light circuit (31) and/or a detection of a light voltage signal present across the light circuit (31) controlling the light current signal via the switch controller (12).
4. The power converter as defined in claim 2, the control circuit (10) further comprising a charge controller (14) for in response to a detection of a source current signal flowing in a direction of the source circuit (41) and/or a detection of a source voltage signal present across the source circuit (41) and/or the detection of the solar voltage signal controlling the charging of the source circuit (41) via the switch controller (12).
5. The power converter as defined in claim 1, further comprising
a first switch (5) with a reverse diode (6), a first main contact of the first switch (5) being coupled to one of the first terminals (1),
an inductor (7), a first main contact of the inductor (7) being coupled to a second main contact of the first switch (5), and a second main contact of the inductor (7) being coupled to one of the second terminals (3), and
- a second switch (8) with a bypass diode (9), a first main contact of the second switch (8) being coupled to the second main contact of the first switch (5), and a second main contact of the second switch (8) being coupled to the other ones of the first and second terminals (2, 4).
6. The power converter as defined in claim 5, the first switch (5), in the first mode, being switched on and off and the second switch (8), in the first mode, being switched off, and the first switch (5), in the second mode, being switched off and the second switch (8), in the second mode being switched on and off.
7. The power converter as defined in claim 5, the respective first and second switches (5, 8) being synchronous rectifiers in the respective second and first modes.
8. The power converter as defined in claim 1, the first mode being a buck mode and the second mode being a boost mode.
9. The power converter as defined in claim 1, the first branch comprising a serial connection of the solar circuit (21) and a rectifier circuit (22).
10. The power converter as defined in claim 1, the second branch comprising a parallel connection of the light circuit (31) and a first capacitor (32).
11. The power converter as defined in claim 1, the source circuit (41) comprising a second capacitor or a battery or a cell or comprising a battery or a cell coupled in parallel to a second capacitor (42).
12. The power converter as defined in claim 1, a maximum of an amplitude of the solar voltage signal being smaller than an amplitude of a light voltage signal present across the light circuit (31) when the light circuit (31) is producing light, the light circuit (31), when receiving the maximum of the amplitude of the solar voltage signal, drawing a negligible current signal.
13. The power converter as defined in claim 1, a maximum of an amplitude of the solar voltage signal being larger than an amplitude of a source voltage signal present across the source circuit (41) when the source circuit (41) is being charged or is feeding the light circuit (31).
14. A system comprising the power converter as defined in claim 1 and further comprising the source circuit (41) and/or the solar circuit (21) and/or the light circuit (31).
15. A method for in a first mode of a power converter charging a source circuit (41) via a solar circuit (21) and for in a second mode of the power converter feeding a light circuit (31) via the source circuit (41), the power converter comprising first terminals (1, 2) to be coupled to a parallel connection of first and second branches, the first branch comprising the solar circuit (21), and the second branch comprising the light circuit (31), and the power converter comprising second terminals (3, 4) to be coupled to the source circuit (41), the method comprising the step of
bringing the power converter into the first and second modes.
PCT/IB2013/061408 2013-01-17 2013-12-30 Power converter for charging and feeding WO2014111778A1 (en)

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US201361753481P 2013-01-17 2013-01-17
US61/753,481 2013-01-17

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030230334A1 (en) * 2002-06-13 2003-12-18 Koninklijke Philips Electronics N.V. Autonomous solid state lighting system
US20090027001A1 (en) 2007-07-27 2009-01-29 Haines Lance P Solar powered apparatus
US20100102773A1 (en) * 2008-10-27 2010-04-29 Laszlo Lipcsei Circuits and methods for power conversion

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030230334A1 (en) * 2002-06-13 2003-12-18 Koninklijke Philips Electronics N.V. Autonomous solid state lighting system
US20090027001A1 (en) 2007-07-27 2009-01-29 Haines Lance P Solar powered apparatus
US20100102773A1 (en) * 2008-10-27 2010-04-29 Laszlo Lipcsei Circuits and methods for power conversion

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