GB2201558A

GB2201558A - Generator for the production of electrical energy particularly from solar energy

Info

Publication number: GB2201558A
Application number: GB08803895A
Authority: GB
Inventors: Chou Isidore Ah; Eric Jeune
Original assignee: AGENCE FSE MAITRISE EN; POLYNESIE FRANCAISE; Commissariat a lEnergie Atomique CEA
Current assignee: AGENCE FSE MAITRISE EN; POLYNESIE FRANCAISE; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 1987-02-24
Filing date: 1988-02-19
Publication date: 1988-09-01
Anticipated expiration: 2008-02-19
Also published as: GB8803895D0; FR2612010A1; GB2201558B; AU1215688A; AU608292B2; NZ223591A

Abstract

An electrical energy source 1, comprising a photovoltaic cell array, 2, 3, or battery 5 and a load 7 are interconnected by switches I1, I2 which are controlled by a circuit 17 in dependence on comparisions amongst the actual battery voltage VB, minimum and maximum desired battery voltages, and the source voltage VP sensed up stream of a diode 19. References Vm1, Vm2 in the region of and respectively lower and higher than a nominal maximum battery voltage, and Vm1, Vm2 in the region of and respectively lower and higher than a nominal minimum battery are used. Switch I1 may be opened when VB>Vm2 or VP<VB, and is closed when VB<Vm1 or VP>(VB+K), where K is chosen to prevent surging of the switch in the case of limited variations in VB and VP. Switch I2 may be opened when VB<Vm1 and closed when VB>Vm2. In a second embodiment, (Fig 5) which may be used to charge a battery during the day and energise a lamp at night, switch I1 is opened when VB>Vm2 and closed when VB<Vm1, and switch I2 is opened when VB<Vm1 and/or VP>(VB+k) and closed when VB>Vm2 and VP<VB. A third embodiment, (Fig 7), is effectively a combination of the first two, switch I1 being controlled in dependence on comparison of VB with VP, Vm1 and Vm2 and switch I2 being controlled in dependence on comparison of VB with VP, Vm1 and Vm2 <IMAGE>

Description

GENERATOR FOR THE PRODUCTION OF ELECTRICAL ENERGY PARTICULARLY FROM SOLAR ENERGY DESCRIPTION The present invention relates to a generator for producing electrical energy particularly from solar energy.

The invention applies to all electrical energy generators having means for producing energy, means for accumulating energy, means for regulating energy accumulation and an electrical output connected e.g. to use means. The invention more particularly applies to an electrical energy generator, which produces electrical energy from solar energy, the production means incorporating in this case photovoltaic cells.

In known manner, a photovoltaic cell converts the energy of photons into electrical energy. In order to obtain high voltages1 advantageously several cells of this type are connected in series, which are regrouped into photovoltaic modules,.a module having approximately 30 photovoltaic cells in series. Moreover, to obtain high currents, several modules are connected in parallel. The means for producing electrical energy from solar energy consequently have one or more modules in series and/or in parallel.

Throughout the remainder of the description the term production devices will relate to a group of one or more modules in series.

In order to be able to produce e.g. a power of approximately 400 watts, advantageously use is made of 5 production devices in parallel, each means having two modules in series of 35 photovoltaic cells in series.

Fig. 1 diagrammatically shows a known electrical energy generator, whose production means 1 comprise production devices 2 in series, each production device having several modules 2 in series. The electrical energy generator shown in Fig. 1 also comprises accumulation means 5 for accumulating energy, regulation means 9 for regulating energy accumulation and an electrical output connected to use means 7.

Each production device 2 is connected via a non-return diode 11, e.g. of silicon to regulation means 9, which are also connected to the accumulation means 5 and the use means 7.

Means 1, 5, 7 and 9 are obviously also connected to a reference potential, such as earth potential or the potential of the negative terminal of the accumulation means.

The accumulation means 5 e.g. incorporate in series one or more accumulation batteries, as a function of the maximum power produced by the production means 1 and the nominal voltage of the batteries used. Using once again the example referred to hereinbefore, in which the production means produce 400 watts power, use is made of e.g. two batteries with a nominal voltage of 12 volts.

The regulation means 9 have two functions, namely protecting the accumulation means 5 against overloads and against excessive discharges so that no-damage occurs thereto. Thus, for accumulation means 5 incorporating e.g. a battery of nominal voltage 12 v, the maximum charging voltage VM of said battery is preferably approximately 14 v and the minimum charging voltage Vm approximately 11 v. Charging the battery to a value higher than the maximum charging voltage VM causes problems such as the boiling of the liquid contained in the battery. Discharging the battery at a value below the minimum charging voltage Vm leads to problems, such as the sulphatlng of the battery.

When the effective charging voltage VB of accumulation means 5 is between the maximum charging voltage VM and the minimum charging voltage Ym, the regulation means 9 permit both accumulation in accumulation means 5 and use by use means 7 of the energy produced by production means 1. However, when the effective charging voltage of the accumulation means 5 exceeds the maximum charging voltage, the regulation means 9 only permit the use of the energy stored in the accumulation means 5. When the effective charging voltage of accumulation means 5 drops below the min-imum charging voltage, the regulation means 9 only permit the accumulation of the energy produced by production means 1 in accumulation means 5, whereas the use means 7 can no longer use energy.

The non-return diodes 11 make it possible to avoid the discharge of accumulation means 5 into production devices 2 via regulation means 9, when the voltage supplied by the production means is below the effective charging voltage of the accumulation means 5. The effective charging voltage of the accumulation means 5 corresponds to the voltage between the positive terminal and the negative terminal of the accumulation means 5.

The use of non-return diodes 11 in a -known electrical energy generator of the type described hereinbefore leads to numerous disadvantages. These are in particular an energy loss due to the voltage drops caused by the diodes. Thus, a module of 30 photovoltaic cells produces a power of approximately 25 watts and a non-return diode 11 consumes approximately 1.6 watt and, in the case of a silicon diode, leads to a voltage drop of approximately 0.8 V. Moreover, these diodes must be placed in a case so as to be protected from external effects and must be associated with coolers to prevent them heating excessively.

Thus, these different elements increase costs and also the complexity of the electrical energy generator.

The object of the present inyention is to obviate these disadvantages and in particular to provide an electrical energy generator having regulation means making it possible to regulate the energy accumulation as a function of the voltage supplied by the production -means, which makes it possibl-e not to use a diode for each production device and which also makes it possible to use energy day and/or night, e.g. in the case of a photovoltaic generator.

More specifically, the present invention relates to an electrical energy generator having electrical energy production means, energy accumulation means, regulation means for regulating energy accumul-ation and an electrical output, said regulation means being connected to the production means, to the accumulation means and to the electrical output of the generator, the latter being characterized in that the regulation means comprise first and second switches in series positioned between the production means and the generator output, the centre point of said switches in series being connected to the accumulation means and control means for controlling the first and second switches as a function of the voltage Vp supplied by the production means, the effective charging voltage VB supplied by the accumulation means and the maximum and minimum charging voltages of the accumulation means.

Advantageously, the production means have a single production device and the regulation means comprise a diode disposed between the production means and the first switch, the control means being directly connected-to said production device.

According to a variant, the energy production means have several production devices in parallel and the regulation means comprise a diode located between a production device and the first switch, the other production devices being connected to the first switch and the control means are directly connected to said production device.

The didde of the regulation means is preferably a Schottky diode, which has the characteristic of only bringing about a voltage drop of approximately 0.4 V. This diode makes it possible to avoid the discharge of the accumulation means into the production device to which same is connected, when the effective charging voltage VB of the accumulation means exceeds the voltage VP supplied by the production device. In this way, the voltage sampled by the control means directly at the output of the production device corresponds to the voltage supplied by said production device. In the case of a photovoltaic generator, this voltage is characteristic of the sunlight.

The diode used in the generator according to the invention forms part of the regulation means and is advantageously located in the same case as the other elements of the regulation means.

According to a preferred embodiment, the control means comprise: - first comparison means connected to the accumulation means and to the production means for comparing the voltage Vp supplied by the production means, the effective charging voltage VB of the accumulation means and at least one reference voltage characteristic of the maximum charging voltage VM of the accumulation means; - first amplification means connected to the first comparison means and to the first switch for amplifying the electric signal supplied by the first comparison means, said amplified signal leading to the opening or closing of the first switch; - second comparison means connected to the accumulation means for comparing the effective charging voltage of the accumulation means and at least one reference voltage characteristic of the.

minimum charging voltage Vm of the accumulation means; and - second amplification means connected to the second comparison means and to the second switch for amplifying the electric signal supplied by the second comparison means, said amplified signal leading to the opening or closing of the second switch.

For the comparison performed by the first comparison means, it is possible to use both a reference voltage such as the maximum charging voltage VM. and several reference voltages surrounding the voltage VM.

In the same way, for the comparison performed by the second comparison means, it is possible to use both reference voltage such as the minimum charging voltage Vm and several reference voltages surrounding voltage Vm Advantageously, the first comparison means compare the voltage Vp the voltage VB and first and second reference voltages VM1 and V such that VMl < VM < VM2 produced from said first comparison means, the electric signal supplied by said first comparison means and amplified by the first amplification means opening the first switch when the voltages VB, Vp and V2 are such that VB > VM2 and/or Vp < V8 and closing said first switch when the voltages VB, Vpi VMl and VM2 are such that VB < VMl and/or VP > VB+ K, in which K is chosen so as to prevent surging of the switch in the case of limited variations of the voltages VB and Vp and in that the second comparison means compare the voltage VB and first and second reference voltages Yml and Vm2 such that Vm1 < Vm < Vm2 produced from said second comparison means1 the electric signal supplied by said second comparison means and amplified by said second amplification means opening the second switch when the voltages VB and Vm1 are such that 9B < Vmi and closing said second switch when the voltages VB and Vm2 are such that VB > Vm2.

The condition VB > VM2 leading to the opening of the first switch makes it possible to avoid overloading of the accumulation means. Condition V P < VB also bringing about the opening of the first switch makes it possible to prevent any discharge of the accumulation means into the production devices connected downstream of the diode. This condition is proved e.g. in the particular case of a photovoltaic generator, when the solar energy is low and such that the voltage VP supplied proves this condition.

Condition VB < VM1 leading to the closing of the first switch permits the charging of the accumulation means without any risk of overload. Condition V VpoVB+ K leading to the closing of the first switch permits the charging of the accumulation means without any risk of the latter discharging into the production means.

Condition VB < Vml leading to the opening of the second switch makes it possible to avoid any discharging of the accumulation means with the risk of damage thereto, by making impossible any use of energy. Condition VB > Vm2 leading to the closing of the second switch particularly authorizes the discharging of the accumulation means by use of energy e.g. by the use means connected to the generator output, without any risk of damaging the accumulation means.

In the case of a photovoltaic generator, this embodiment permits a use of energy both day and night, provided that the condition VB > Vm'2 is proved.

For charging voltages VB, whose values are between the reference voltages VM1 and YM2 (VMlsVB4vM2) or reference voltages Vm1 and Vm2 tVml4VB4Vm2), the first and second switches remain in the state which they had before these conditions were proved in other words if they were open they remain open and if they were closed they remain closed.The fact of using reference voltages surrounding the maximum charging voltage and reference voltages surrounding the minimum charging voltage makes it possible to-avoid the opening or closing of switches as a result of small variations to the voltages VB and BP. Thus, these reference voltages make it possible to stabilize the control of the first and second switches.

According to another preferred embodiment, the control means comprise first comparison means connected to the accumulation means for comparing the effective charging voltage VB, accumulation means and at least one reference voltage characteristic of the maximum charging voltage VM of the accumulation means; first amplification means connected to the first comparison means and to the first switch for amplifying the electric signal supplied by the first comparison means, said amplified signal leading to the opening or closing of said first switch; second comparison means connected to the accumulation means and to the production means for comparing the voltage Vp supplied by the production means, the effective charging voltage B of the accumulation means and at least one reference voltage characteristic of the minimum charging voltage Vm of the accumulation means; and second amplification means connected to the second comparison means and to the second switch for amplifying the electric signal supplied by the second comparison means, said amplified signal leading to the opening or closing of said second switch.

The production means of said generator preferably only have a single production device, in view of the fact that the first -switch is not controlled as a function of the voltage Vp supplied by the production means.

As hereinbefore, it is possible to use for the comparison by-the first comparison means, the maximum charging voltage VM or preferably the reference voltages VM1 and VM2 and for the comparison by the second comparison means, the minimum charging voltage Vm or preferably the reference voltages Vml and Vm2.

Thus, advantageously,the first comparison means compare the voltage VB and a first and a second reference voltages VM1 and VM2 such that YM1 < VM < VM2 produced from said second comparison means, the electric signal supplied by said first comparison means amplified by the first amplification means opening the first switch when the voltages VB and VM2 are such that VB > VM2 and closing said first switch when the voltages VB and VMl are such that VB < VM1 and in that the second comparison means compare the voltage Vp, the voltage VB and a first and a second reference voltages Vml and Vm2 such that Vml < Vm < Vm2 produced from said second comparison means, the electric signal supplied by said second comparison means amplified by the second amplification means opening the second switch when the voltages VB, VP and Vml are such that VB < Vml and/or Vp > VB and closing said second switch when the voltages VB, VP, Vml and Vm2 are such that V > Vm2 and VP < VB-K, in which k is chosen so as to prevent surging of the switch in the case of minor variations to the voltages VB and VP In the particular case of a photovoltaic generator, condition V P < VB+k leading to the closing of the second switch and therefore the possibility of using energy is proved when the solar energy is low and such that the voltage Vp proves said condition.However, the condition VP > VB leading to the opening of the second switch and consequently the impossibility of using energy is proved when the solar energy is high and such that the voltage Vp proves said condition.

Thus, in the case of a photovoltaic generator, this embodiment makes it possible to use energy only at night. For example, this generator can be used for lighting up pedestal lamps at nightfall and for extinguishing them at daylight.

According to another embodiment,the control means comprise first comparison means connected to the accumulation means and to the production means for comparing the voltage Vp supplied by the production means, the effective charging voltage VB of the accumulation means and at least one reference voltage characteristic of the maximum charging voltage VM of the accumulation means; first amplification means connected to the first comparison means and to the first switch for amplifying the electric signal supplied by the first comparison means, said amplified signal leading to the opening or closing of said first switch; second comparison means connected to the accumulation means and to the production means for comparing the voltage Vp supplied by the production means, the effective charging voltage V B of the accumulation means and at least one reference voltage characteristic of the minimum charging voltage Vm of the accumulation means; and second amplification means connected to the second comparison means and to the second switch for amplifyirig the electric signal supplied by the second comparison means, saidamplified signal leading to the opening or closing of said second switch.

The production means of said generator can have several production devices, in view of the fact that the first switch is controlled in particular as a function of the voltage supplied by the production means, thus making it possible to prevent any discharge of the accumulation means into the production means.

As hereinbefore, for the comparison by the first comparison means, it is possible to use the maximum charging voltage VM or preferably the reference voltages VM1 and VM2 and for the comparison by the second comparison means the minimum charging voltage Vm or preferably the reference voltages Vml and Vm2 Thus, advantageously, the first comparison means compare the voltage Yp, the voltage V B and a first and a second reference voltages VMl and VM2 such that YMI < VM < VM2 produced from said first comparison means, the electric signal supplied by said first comparison means amplified by the first amplification means opening the first switch when the voltages VB, Vp and VM2 are such that VB > VM2 and/or V < VB and closing said first switch when the voltages VB, VP VMl and VM2 are such that Vp < VMl and/or VP > VB+ K and in that the second comparison means compare, the voltage Yp, the voltage VB and a first and a second reference voltages Vml and Vm2 such that Vmi < V < Vm2 produced m from said second comparison means, the electric signal supplied by sa-id second comparison means amplified by the second amplification means opening the second switch when the voltages VB and Vml are such that VB < Vml and/or Vp > VB and closing said second switch when the voltages VB, VP, Vml and Vm2 are such that VB > Vm2 and/or Vp < VB+ k.

In the case of a photovoltaic generator, this embodiment makes it possible to use the energy only at night e.g. for supplying pedestal lamps.

Advantageously, an energy production device has several photovoltaic cells in series. These photovoltaic cells in series are regrouped into modules, each module having e.g. 30 photovoltaic cells in series. Thus, a device comprises one or more modules in series.

Advantageously, the first switch and/or the second switch is an electromagnetic relay or a transistor, such as a MOS transistor.

Moreover, the accumulation means preferably have at least one accumulation battery.

The invention is described in greater detail hereinafter relative to non-limitative embodiments and the attached drawings, wherein show: Fig.l Already described, diagrammatically a known electrical energy generator.

Fig. 2 Diagrammatically an electrical energy generator according to the invention.

Fig. 3 Diagrammatically a first embodiment of the regulation means of an electrical energy generator according to the invention.

Fig. 4 A more detailed embodiment of the regulation means shown in Fig. 3.

Fig. 5 Diagrammatically a second embodiment of the regulation means of an electrical energy generator according to the invention.

Fig. 6 A more detailed embodiment of the regulation means shown in Fig. 5.

Fig. 7 Diagrammatically a variant of the embodiment shown in Fig. 5.

For reasons of clarity, the description is given for electrical energy generators of the photovoltaic type, in other words the electrical energy production means incorporate photovoltaic cells, but obviously these examples are not limitative.

Fig. 2 diagrammatically shows an electrical energy generator according to the invention. This generator comprises electrical energy production means 1 having several production devices 2 in parallel. Each of these devices has pliotovoltaic cells in series grouped into modules 3. A production device can have one or more modules in series. Obviously the production means 1 may only have a single production device.

This generator also comprises energy accumulation means 5, such as one or more accumulating batteries, regulatio means 15 for regulating energy accumulation and an electrical output connected e.g. to use means 7 for using the electrical energy.

The regulation means 15 are connected to production means 1, to accumulation means 5 and to use means 7. Means 1, 5, 7 and 15 are connected to a reference potential, such as earth potential, as shown in the drawing, or the potential of the negative terminal of the accumulation means.

The regulation means 15 according to the invention incorporate control means 17, a first and a second switch 11 and I2 in series and a diode 19, such as a Schottky diode Diode 19 is connected between a single production device 2 and switch 111 the other production devices, in the case where the production means have several such devices, being connected directly to the first switch downstream of diode 19.

Control means 17 are connected to the accumulation means 5, to-the production means 1 upstream of diode 19 and to switches I1 and 12. Moreover, the centre point of switches 11 and I2 is connected to the accumulation means 5 and switch I2 to use means 7.

By stopping a possible discharge of the accumulation means1 diode 19 makes it possible to take a voltage equal to the voltage supplied by the production device to which it is connected, said voltage corresponding to the voltage supplied by the production means.

Means 17 make it possible to analyze, as will be shown hereinafter, -the voltage Vp taken upstream of diode 19, the effective charging voltage VB of accumulation means 5 and reference voltages characteristic of the maximum and minimum charging voltages VM and Vm of the accumulation means 5 and are able to control as a function of these voltage values the opening or closing of switches Il and 12, so as to cause no damage to accumulation means 5 and in accordance with the desired use of the electrical energy produced by the generator.

As has been shown hereinbefore, these reference voltages are the maximum and minimum charging voltages VM and Vm or the voltages VMll VM2 and Vml, Vm2 surrounding said values (VMl < VM < VM2 and Vm1 < Vm < Vm2) To stabilize the control of the switches, the preferred reference voltage used is VMll VM2 and Vml, Vm2 Throughout the remainder of the description, reference voltages VNl, VM2, Yml, Vm2 will be used as examples.

Thus, when switches Il and 12 are closed, the energy produced by the production means 1 is stored in the accumulation means Sand can be used by the use means 7.

When switch Il is closed and switch I2 open, the energy produced by production means 1 is only accumulated in the accumulation means 5. Conversely, when switch 11 is open and switch I2 closed, no energy is accumulated in the accumulation means 5, but conversely the energy used by the use means 7 comes from the accumulation means 5.

Fig. 3 gives an embodiment of the regulation means of an electrical energy generator according to the invention. It is possible to see the control means 17, diode 19 and switches I and I2, together forming the regulation means.

In this case, the control means 17 have first comparison means 21 connected to the production means upstream of diode 19, to the accumulation means 5 and to the first amplification means 23, the latter also being connected to switch Il, The control means 17 also have second comparison means 25 connected to the accumulation means 5 and to the second amplification means 27, the latter also being connected to switch 12.

Comparison 21 compare the voltage Vp supplied by the production means 1, the effective charging voltage VB of the accumulation means 5 and the reference voltages VMl and VM2 produced by comparison means 21. Comparison means 25 compare the charging voltage VB of accumulation means 5 and the reference voltages Vml and Vm2 produced by comparison means 25.

For information purposes, for accumulation means 5 of nominal voltage 12 v, the maximum charging voltage being approximately 14 v, e.g. the two reference voltages VMl and VM2 are respectively chosen as 13.5 and 14.4 v. Moreover, as the minimum charging voltage is approximately 11.5 v, e.g. the two reference voltages Vml and Vm2 are respectively chosen as 10.5 and 12.2 v.

Thus, when voltage V B is such that VB > VM2, the electric signal from comparison means 21, amplified by amplification means 23, leads to the opening of switch Il and the same occurs if voltage Vp is such that VP < VB Conversely, when voltage VB is such that VB < VMI and/or voltage Vp is such that Vp > VB+ K, switch Il is closed by the electrical signal from the comparison means 21 and the amplification'means 23.

Moreover, when the voltage V B is such that YB < Vml, the electrical signal from the comparison means 25 amplified by the amplification means 27 leads to the opening of switch 12.

Conversely, when voltage VB is such that VB > Vm2, the signal from comparison means 25, amplified by amplification means 27, leads to the closing of said switch 12.

Fig. 4 shows in greater detail an embodiment of the regulation means 15 of Fig. 3. In the latter, the reference potential of the different elements of the generator and the use means is the potential at a reference point B connected by a diode D8 to the negative terminal of the accumulation means 5-. Diode D8 is e.g. of type lN4004.

Moreover, in this case, switches 11 and 12 are electromagnetic relays respectively having inductive coils B1 and 82* To avoid overvoltages,-diodes D1 and D2 are respectively connected to the terminals of coils B1 and B2.

Comparison means 21 incorporate a resistor R1 connected on the one hand upstream of diode 19 and on the other to a diode D3, a resistor R2 connected on the one hand to the positive terminal of accumulation means 5 (or point A) and on the other to diode D3 and to the base of a transistor T1, whose emitter is connected to point A.

Comparison means 21 also have between point A and point 8, five resistors in series R4, R5, P1, R6,R7, the collector of transistor El being connected to the centre of resistors R and 6 R7 by a resistor R3. Resistor P1 is a variable potentiometer.

Moreover, between the centre of resistors R4 and R5 and point B is connected a capacitor C1, such as an electrochemical capacitor.

Moreover, a transistor T2 is connected by its emitter tm potentiometer P1, by its collector to point A via a resistor R8 and by its base.between a resistor R9 and a diode Z1 of the Zener diode type. The other end of resistor R9 is connected to point A and the other end of diode Z1 to point B.

These comparison means are connected to the amplification means 23 by the centre of resistors R6 and R7 and by the centre of resistor R8 and the collector of transistor T2.

Amplification means 23 have a transistor T3, whose base is connected between resistor R8 and the collector of transistor T2 The emitter of transistor T3 is connected to point A and its collector is connected via two resistors in series R11 and R12 to point B. Means 23 also include a transistor T4, whose base is connected to the centre of resistors Rll and R12, whose emitter is connected to point B and whose collector is connected both to the centre of resistors R6, R7 by a resistor Rlo and to one end of the inductive coil B1 of switch 11 The other end of coil B1 is connected to point A.

Comparison means 25 have between points A and B five resistors in series R13, R14, P2, R15, R16. resistor p2 being a potentiometer. Between the centre of resistors R13, R14 and point B is connected a capacitor C2, such as an electrochemical capacitor. Moreover, a transistor T5 is connected by its emitter to potentiometer 2 by its collector to point A via a resistor R17 and by its base between a resistor R18 and a diode Z2 of the Zener diode type. Resistor R18 is also connected to point A and diode Z2 to point B.

Amplification means 27 incorporate a transistor T6, whose base is connected to the centre of resistor R17 and the collector of transistor T5. The emitter of said transistor is connected to point A and the collector is connected via two resistors in series R20 and R21 to point B. Means 27 also have a transistor T7, whose-base is connected to the centre of resistors R20 and R21, whose emitter is connected to point B and whose collector is connected both to the centre of resistors R15,R16 via a resistor R19 and to one end of inductive coil B2, the other end of the latter being connected to point A. A For information purposes, the following table 1 gives the values of the resistors and capacitors usable in said embodiment, as well as the types of transistors and diodes.

I A B L E E

R1 R2 R3 R4 R5 R6 R7 1,2k # 820 # 3,3k # 6,8k # 2,2k # 1k # 270 # R8 R9 R10 R11 R12 R13 R14 217 # 3.3k # 12k # 2.7k # 820 # 6.8k # 2,2k # R15 R16 R17 R18 R19 R20 R21 2,7k # 560 # 2,7k # 3,3k # 10k # 2.7k # 820 # #1 #2 C1 C2 D1 D2 D3 4,7k # 4,7k # 220 F 220 F 1N4148 1N4148 1N4004 Z1 Z2 T1 T2 T3 T4 T5 6,8V 6,8V 2N2905 2N1711 2N2905 2N1711 2N1711 T6 T7 2N2905 2N1711 The reference voltages VMl and VM2, Vml and Vm2 are not really reproduced by comparison means 21 and 25.In fact, a voltage divider bridge takes a fraction of the voltage of battery 5 and compares it with reference voltages produced by diodes 7 and Zener diodes Zl and Z2. The reference voltages VMl and VM2, Vml and Vm2 are represented by a fraction of their value, namely WMI and WM2, Wml and Wm2 In the same way, voltage VB of battery 5 is represented by WB.

In order to carry out the comparison of VB and VM2, transistor T2 compares voltage WB with voltage WM2 produced by the Zener diode Z1. When the comparator changes state, the amplification means 23 follow and give a return signal called the feedback signal passing through resistor R10. On clearing the threshold VM2, it is momentarily erased. Thus, the feedback signal adds a supplementary value H to the divider bridge. Thus, transistor T2 compares voltage WB+ H with VM2, which amounts to comparing We and VM2 - H. The negative feedback is calculated in such a way that WM2 - H = WMl. Consequently this amounts to comparing WB with WMl or VB with VMl. If the threshold VMl is cleared, the feedback disappears and the comparison with threshold VM2 can take place again.The reasoning is the same for the second comparison means 25.

In order to carry out the comparison between VB and Vm2 transistor T5 compares voltage WB with Wm2 which is produced by Zener diode Z2. When the comparator changes state, the amplification means 27 follow and give a return signal or feedback signal passing through resistor Rl9. On clearing threshold Vm2 it is momentarily erased and the feedback signal adds a value h to the divider bridge. Thus, transistor T5 compares voltage WB + X with Wm2, which amounts to comparing WB with Wm2 - h. The nega-tive feedback is calculated in such a way that Wm2 - h = Wml, which amounts to comparing W5 with Wml or V8 with Vml. If threshold Yml is cleared, the feedback disappears and the comparison with threshold Vm2 can take place again.

For the comparison between VB and VP, there is a direct comparison (without voltage divider bridge) by resistor R3, which modifies the divider bridge constituted by resistors R4, R5 and R6, R7.

Thus, the transistor T1 has the following action: - if VP < VB, a current passes through transistor R3 which acts on the divider bridge in a manner comparable to a large increase in V8, which leads to the action of T2 with all its consequences; - if Vp > VB + k, no- current can pass through transistor R3, which allows the divider bridge to fulfil its initial function.

Fig. 5 shows a second embodiment of the regulation means of an electrical energy generator according to the invention.

This embodiment more particularly applies to an energy generator only having one energy production device 2.

Regulation means 15, in the manner described hereinbefore, have a diode 19, a first and a second switches I1 and 12 and control means 17. Only the control means 17 differ from those described hereinbefore. These control means 17 incorporate first comparison means 29 connected to accumulation means 5 and to first amplification means 31, the latter also being connected to switch Il Moreover, the control means 17 incorporates second comparison means 33 connected to the accumulation means 5, to the production means l and to the second amplification means 35, the latter also being connected to the second switch 12.

Comparison means 29 compare the effective charging voltage V B of accumulation means 5 and the reference voltages VMI and VMZ produced by comparison means 29.

Comparison means 33 compare the voltage Vp taken upstream of diode 19 corresponding to the voltage supplied by the production means 1, the effective charging voltage VB of the accumulation means 5 and the reference voltages Yml and Vm2 produced by comparison means 33.

Thus, the control of switch 12 is particularly dependent on voltage Vp In the case of a photovoltaic generator, said voltage Vp makes it possible to analyze the lighting intensity received by the photovoltaic cells. Comparison means 33 and amplification means 35 can consequently control the opening of switch I2 at night and its closing by day, or vice versa.

In the reverse case, the generator makes it possible to supply the use means at night, such as one or more pedestal lamps 8. For this purpose, the electrical energy generator accumulates energy by day and uses its stored energy for supplying means 7 at night.

A generator according to the invention of the type shown in Fig. 5 and used e.g. for supplying means 7 at night, functions in the following way. When the voltages VB, VM1 and VM2 are such that VB > VM2, switch II is open and when VB < VMl switch I, is closed. Moreover, when these voltages VB, Vp, Vml and Vm2 are such that VB > Vml and/or Vp > VB + k, switch I2 is open and when VB > Vm2 and Vp < VB, switch I2 is closed.

Fig. 6 shows in greater detail an embodiment of the regulation means 15 described relative to Fig. 5 and making it possible to e.g. supply a pedestal Iamp 8 at night.

In the drawing, the reference potential of the different components of the electrical energy generator and of the pedestal lamp 8 is as in Fig. 4 the potential of the negative terminal of accumul-ation means 5. In this embodiment, switch Il is an electromagnetic relay of the same type as that described relative to Fig. 4 and switch I2 is a field effect transistor TM.

Thus, it is advantageous to use as a switch a field effect transistor rather than an electromagnetic relay, in view of the fact that the latter consumes much more power than a transistor.

However, the use of a transistor as the switch is only advisable if the current passing through said transistor is relatively constant, i.e. having little or no overload. This condition is proved by switch 12, when the use means 7 are constituted by a pedestal lamp.

For reasons of clarity, the positve and negative terminals of the accumulation means 5 will be respectively designated A and C.

Between point A and point C of the accumulation means 5, comparison means 29 have five resistors in series R24, R25, p3' R26, R27. A capacitor C3, such as an electrochemical capacitor, is connected between the centre of resistors R24, R25 and point C. Resistor p3 is a potentiometer. The comparison means 29 also have a transistor T9, whose emitter is connected to point C via a diode Z3 of the Zener diode type, whose collector is connected across two resistors in series R29, R28 to point A and whose base is connected to potentiometer p3. A resistor R30 is also connected between the emitter of transistor T9 and point A.

The amplification means 31 incorporate a transistor T10, whose base is connected to the centre of resistors R29 and R28, whose emitter is connected to point A and whose collector is connected to the base of a transistor Tll.A resistor R32 is also connected between the collector of -transistor T10 and the emitter of transistor Toll. The collector of transistor T11 is connected to point A and the emitter of said transistor is also connected to one end of the inductive coil B1 of switch I the other end of the coil being connected to point C.As described hereinbefore, advantageously a diode Dl is connected to the terminals of coil B The comparison means 33 have a diode D5 connected to the production means 1 upstream of diode 19 and to a resistor R22, which is itself connected to the base of a transistor . The 8 emitter of transistor T8 is connected to point A and its collector is connected to point C via a resistor R23.

Means 33 also include a transistor T12, whose base is connected to the collector of transistor T8, whose collector is connected to point A and whose emitter is connected to point C across five resistors in series R33, R34, P4, R35, R36, resistor 4 being a potentiometer. A capacitor C4, such as an electrochemical capacitor is connected between the centre of resistors R33, R34 and point C. Means 33 also include a transistor T13, whose base is connected to a potentiometer P4, whose collector is connected by two resistors in series R39, R38 to point A and whose emitter is connected by a diode Z4 of the Zener diode type to point C. A resistor R40 is connected between point A and the emitter of tr-ansistor T13.

Amplification means 35 incorporate a transistor T14, whose base is connected to the centre of resistors R39 and R38, whose emitter is connected to point A and whose collector is connected to point C by two resistors in series R42 and R43.

Moreover, the collector of this transistor is connected across a resistor R4l to the centre point of resistors R35 and R36, said centre also being connected to point C by a resistor R37 The centre of resistors R42 and R43 is connected to the gate of transistor TM constituting switch 12 and to a Zener-type diode Z5 also connected to point C. The source of transistor TM is connected to point C and its drain is connected by a resistor R44 to point A. The use means 7 incorporating a, pedestal lamp 8 are connected between the ends of resistor R44.

The position of resistor R44 and consequently the pedestal lamp 8 between switches 11 and 12,-instead of being on the other side of transistor TM, means that the latter is a N channel transistor. In the case of a P channel transistor T, resistor 44 would be located on the other side of switch I2, i.e. as in Fig. 5.

For information purposes, the following table gives the values of the resistors and capacitors usable in this embodi ment, -as- well as the types of transistors and diodes.

T A B L E @ 2

R22 R23 R24 R25 R26 R27 R28 10k # 22k # 3,3k 1k # 1k # 360 # 2,7k # R29 R30 R31 R32 R33 R34 R35 3.3k # 5,6k # 12k # 820 # 4,7k # 1.8k # 4,7k # R36 R37 R38 R39 R40 R41 R42 390 # # 3,3k # 10k # 5.6k # 2.7k # 2,2k # R43 R44 3 4 C3 C4 D5 6,8k # 10k # 2,2k # 2,2k # 470 F 470 F 1N4004 Z3 Z4 Z5 T8 T9 T10 T11 4.7V 4.7V 15V BC177 2N1711 2N2905 2N1711 T12 T13 T14 TM 2N1711 2N1711 2N2905 BUZ10 The reference voltages YMI and VM2, Vml and Vm2 are not really reproduced by the comparison means 29 and 33.Thus, a voltage divider bridge takes a fraction of the voltage from battery 5 and compares it with reference voltages produced by Zener diodes Z3 and Z4. The reference voltages VM1, VM2, Vml and Vm2 are represented by a fraction of their value. i.e.

WMl, WM2 Wml and Wm2 In the same way voltage V B of battery 5 is represented by WB.

In order to carry out the comparison of VB and VM2, transistor T9 compares voltage WB with voltage WM2, which is produced by the Zener diode Z3 When the comparator changes state, the amplif-ication means 31 follow and give a return signal, called the feedback signal passing through R31. When threshold VMl is cleared, it is momentarily erased. Thus, the feedback signal adds a supplementary value H to the divider bridge. Thus, transistor T9 compares voltage W8 + H with WM2, which amounts to comparing WB with WM2 - H. The feedback is calculated in such a way that WM2 - H WMl, which amounts to comparing WB with WM1 or VB with VMl.On clearing threshold VMl, the feedback disappears and the comparison with threshold VM2 can again take place. The reasoning is the same for the second comparison means 33.

To carry out the comparison of VB with V 2, transistor T13 compares voltage WB with voitage Wm2 produced by the Zener diode Z4 when the comparator changes state, amplification means 35 following and giving a return or feedback signal passing through R41. On clearing threshold Vm2, it is momentarily erased, so that the feedback signal adds a value h to the divider bridge.

Thus, transistor T13 compares the voltage WB + h with Wm2, which amounts to comparing WB with Wm2 - h. The feedback is calculated in such a way that Wm2 - h = Wml, which therefore amounts to comparing We with Wml or Va with V On clearing threshold V the feedback disappears and it is again possible to carry out a comparison with threshold Vm2 For the comparison between V8 and VP, there is a direct comparison (without voltage divider bridge) by transistor T8.

The latter supplies a signal which blocks or saturates transistor T12, the latter supplying the voltage divider bridge constituted by resistors R39, R34, p4, R35 and R36.

The action of transistors T8 and T12 is as follows: with Vp < VB, the voltage divider bridge is normally supplied, so that it can fulfil its initial function, whereas - if Vp > VB + k, the supply of the voltage divider bridge is interrupted and is comparable to a considerable decrease of VB, which leads to the action of transistor Tl3 with all its consequences.

Fig. 7 gives a constructional variant of the electrical energy generator of Fig. 5. In this variant, the energy production means l comprise several production devices 2 in parallel. Moreover, in order that the accumulation means 5 do not discharge into the production devices, apart from that connected to diode 19 when voltages Vp and V8 are such that VpcVB, use is made of comparison means 21 and amplification means 23 of the same type as described relative to Fig. 3, thus making it possible to compare these two voltages and amplify the signal from means 21 for controlling the switch Il@as a consequence thereof. The other means are identical to those shown in Fig. 5.

Thus, e.g. for a photovoltaic generator used for supplying pedestal lamps at night, when voltages VB, Yp, VM2 and VMl are such that VB > VM2 and/or Vp < YB, switch I1 is open and when VP > VB + K and VB < VMl switch Il is closed. Moreover, when voltages VB, VP, Vm2, Vml are such that VB < Vml or Vp > VB + k, switch I2 is open and when V8 > Vm2 and Vp < VB switch 12 is closed.

The embodiments of the electrical energy generator according to the invention are in no way limitative and constructional variants can be made thereto without passing beyond the scope of the invention.

Claims

C L A I M S

1. Electrical energy generator having electrical energy production means (1), energy accumulation means (5), regulation means (15) for regulating energy accumulation and an electrical output, said regulation means being connected to the production means (1), to the accumulation means (5) and to the electrical output of the generator, the latter being characterized in that the regulation means comprise first and second switches (Il, 12) in series positioned between the production means and the generator output, the centre point of said switches in series being connected to the accumulation means (5) and control means (17) for controlling the first and second switches as a function of the voltage VP supplied by the production means, the effective charging voltage V8 supplied by the accumulation means and the maximum and minimum charging voltages of the accumulation means.

2. Electrical energy generator according to claim 1, characterized in that the energy production means (1) have a single production device (2) and the regulation means (15) incorporate a diode (19) located between the production device and the first switch (it), the control means (17) being directly connected to said production device.

3. Electrical energy generator-according to claim 1, characterized in that the energy production means (1) have several production devices (2)'in parallel and the regulation means (15) incorporate a diode (19) located between a production device and the first switch (I1), the other production devices being connected to said switch downstream of said diode and the control means (17) are directly connected to said production device.

4. Electrical energy generator according to any one of the claims 1 to 3, characterized in that the control means (17) comprise first comparison means (25) connected to the accumulation means (5) and to the production means (1) for comparing the voltage Vp supplied by the production means, the effective charging voltage V, VB of the accumulation means (5) and at least one reference voltage characteristic of the maximum charging voltage VM of the accumulation means (5); first amplification means (23) connected to the first comparison means and to the first switch for amplifying the electric signal supplied by the first comparison means (21), said amplified signal leading to the opening or closing of the first switch second comparison means (25) connected to the accumulation means (5) for comparing the effective charging voltage of the accumulation means and at least one reference voltage characteristic of the minimum charging voltage Vm of the accumulation means; and second amplification means (27-) connected to the second comparison means (25) and to the second switch (I2) for amplifying the electric signal supplied by the second comparison means, said amplified signal leading to the opening or closing of the second switch.

5. Electrical energy genrator according to claim 4, characterized in that the first comparison means (21) compare the voltage Vp, the voltage VB and first and second reference voltages VMl and VM2, such VMl < VM < VM2 produced from said first comparison means, the electric signal supplied by said first comparison means and amplified by the first amplification means (23) opening the first switch when the voltages VB, Vp and VM2 are such that VB > VM2 and/or Vp < VB and closing said first switch when the voltages VB, Vp' VMl and VM2 are such that VB < VM1 and/or Vp > VB + K, in which K is chosen so as to prevent surging of the switch in the case of limited variations of the voltages V and Vp and in that the second comparison means (25) compare the voltage VB and first and second reference voltages YmI and Vm2 such that Vm1 < Vm < Vrn2 produced from said second comparison means, the electric signal supplied by said second comparison means and amplified by said second amplification means (27) opening the second switch when the voltages VB and Vml are such that V8 < Vm1 and closing said second switch when when the voltages V B and Vm2 are such that VB > Vm2.

6. Electrical energy generator according to any one of the claims 1 and 2, characterized in that the control means (17) comprise first comparison means (29) connected to the accumulation means (5) for comparing the effective charging voltage VB, accumulation means and at least one reference voltage characteristic of the maximum charging voltage VM of the accumulation means; first amplification means (31) connected to the first coniparison means (29) and to the first switch (I1) for amplifying the electric signal supplied by the first comparison means (33), said amplified signal leading to the opening or closing of said first switch; second comparison means connected to the accumulation means (5) and to the production means (1) for comparing the voltage VP supplied by the production means, the effective charging voltage V13 of the accumulation means and at least one reference voltage characteristic of the minimum charging voltage Vm of the accumulation means; and second amplification means (35) connected to the second comparison means (33) and to the second switch (I2) for amplifying the electric signal supplied by the second comparison means, said amplified signal leading to the opening closing of said second switch.

7. Electrical energy generator according to claim 6, characterized in that the first comparison means (29) compare the voltage VB and a first and a second reference voltages VM1 and V112 such that VMl < VM < VM2 produced from said second comparison means, the electric signal supplied by said first comparison means amplified by the first amplification means (31) opening the first switch when the voltages VB and V;;42 are such that V B > VM2 and closing said first switch when the voltages VB and V141 are such that VB < Vtdl and in that the second comparison means (33) compare the voltage VP, the voltage VB and a first and a second reference voltages Vml and Vm2 such that Vm1 < V < Vm2 produced m from said second comparison means, the electric signal supplied by said second comparison means amplified by the second amplification means (35) opening the second switch when the voltages Vg, VP and Vml are such that V8 < Vm1 and/or Vp > VB and closing said second switch when the voltages VB, VP, Vml and Vm2 are such that V@ > V@@ and V P < V B , k, In which k is chosen so as to prevent surging of the switch in the case of minor variations to the voltages VB and Vp.

8. Electrical energy generator according to any one of the claims 1 to 3,-characterized in that the control means (17) comprise first comparison means (21) connected to the accumulation means (5) and to the production means (1) for comparing the voltage Vp supplied by the production means, the effective charging voltage VB of the accumulation means (23) and at least one reference voltage characteristic of the maximum charging voltage Vn of the accumulation means; first amplification means connected to the first comparison means (21) and to the first switch (li) for amplifying the electric signal supplied by the first comparison means (33), said amplified signal leading to the opening or closing of said first switch; second comparison means connected to the accumulation means (5) and to the production means (1) for comparing the voltage Vp supplied by the production means, the effective charging voltage VB of the accumulation means and at least one reference voltage characteristic of the minimum charging voltage Vm of the accumulation means; and second amplification means (35) connected to the second comparison means (33) and to the second switch (I2) for amplifying the electric signal supplied by the second comparison means, said amplified signal leading to the opening or closing of said second switch.

9. Electrical energy generator according to claim 8, characterized in that the first comparison means (21) compare voltage Vp, voltage VB and a first and a second reference voltages VMl and VM2 such that 'V' Ml < VM < Vt2 produced from said first comparison means, the electrical signal supplied by said first comparison means and amplified by said first amplification means (23) opening the first switch when the voltages VB, Yap and VM2 are such that VB > VM2 and/or Vp < VB and closing said first switch when the voltages VB, VP VM1 and VM2 are such that VP < VMl and/or VP > VB + K, in which K is chosen so as to avoid surging of the switch in the case of small variations in tiie voltages VB and V and in that the second comparison means (33) P compare the voltage VP, the voltage VB and a first and a second reference voltages Vml and Vm2 such that Vml < Vm < Vm2 produced from said second comparison means, the electric signal supplied by said second comparison means and amplified by the second amplification means (35) -opening the second switch when the voltages VB and Vml are such that VB < Vml and/or Vp > VB and cloding said second switch when the voltages VB, Vp, Vml and Vm2 are such that VB > Vm2 and VP < VB - k, in which k is chosen in such a way as to prevent surging of the switch in the case of small variations of the voltages VB and VP

10. Electrical energy generator according to any one of the claims 1 to 9, characterized in that an energy production device has several photovoltaic modules in series.

11. Electrical energy generator according to any one of the claims 1 to 10, characterized in that the first switch (I1) and/or the second switch (12) is an electromagnetic relay.

12. Electrical energy generator according to any one of the claims 1 to 10, characterized in that the first switch (I1) and/or the second switch (I2) is a transistor.

13. Electrical energy generator according to any one of the claims 1 to 12, characterized in that the energy accumulation means (5) incorporate at least' one accumulation battery.

14. Electrical energy generator substantially as hereinbefore described with reference to Figs. 2-4 or Figs. 5 and 6 or Fig. 7 of the accompanying drawings.