WO2019233583A1

WO2019233583A1 - Method for connecting a refrigerator to a solar home system and controller

Info

Publication number: WO2019233583A1
Application number: PCT/EP2018/065030
Authority: WO
Inventors: Jingting Cher; Falco Sengebusch
Original assignee: Robert Bosch Gmbh
Priority date: 2018-06-07
Filing date: 2018-06-07
Publication date: 2019-12-12

Abstract

The present invention concerns a method for connecting a refrigerator to a solar home system, which SHS may include an existing photovoltaic module (PVM), a rechargeable battery, and a controller. The controller may include: an input for receiving energy generated by the existing PVM; a battery terminal for the rechargeable battery; an output to be electrically coupled to a load. The method may include the steps of: electrically coupling an additional PVM for providing additional energy to the input; electrically coupling the refrigerator to the output; enabling a power controller for controlling a power supplied by the output to the refrigerator; which control may be in accordance to the additional energy provided by the additional photovoltaic module. The control may be carried out by the power controller. The present invention also concerns a controller, which may be adapted for being use in the method of the present invention.

Description

METHOD FOR CONNECTING A REFRIGERATOR TO A SOLAR HOME

SYSTEM AND CONTROLLER

FIELD OF THE TECHNOLOGY

[0001] The present disclosure relates to a method for connecting a refrigerator to a solar home system (SHS). The present disclosure also relates to a controller for the solar home system.

BACKGROUND ART

[0002] Conventional solar home systems are known that convert solar energy into AC power thus being able to power, at great power expenses, conventional AC refrigerators. Also single off-grid refrigerator systems are known, comprising a photovoltaic (PV) panel, a refrigerator, a rechargeable battery and a dedicated controller. These systems are costly, in particular for many rural communities in developing countries. One of the main cost drivers are the batteries. The dedicated controller is also a cost driver.

[0003] Therefore, there is a need to provide for alternative refrigerator systems powered by a photovoltaic module.

SUMMARY

[0004] It is therefore, object of the invention to provide an improved method for connecting a refrigerator to a solar home system and to a controller. The refrigerator includes a refrigerator power load. The solar home system may include an existing photovoltaic module, a rechargeable battery, and a controller. The controller may include an input configured to receive energy generated by the existing photovoltaic module. The controller may include a battery terminal configured to be electrically connected to the rechargeable battery. The controller may include an output configured to be electrically coupled to a load. The method may include the step of electrically coupling an additional photovoltaic module to the input of the controller, wherein the additional photovoltaic module is configured to provide an additional energy. The method may include the step of electrically coupling the refrigerator to the output. The method may include the step of enabling a power controller for controlling a power supplied by the output to the refrigerator. The method may include the step of controlling the power supplied by the output to the refrigerator, which control may be in accordance to the additional energy provided by the additional photovoltaic module. The control may be carried out by the power controller.

[0005] The controller may be adapted for being use in the method of the present invention.

[0006] The controller may include an input configured to receive energy generated by an existing photovoltaic module, a battery terminal configured to be electrically connected to a rechargeable battery, and an output configured to be electrically coupled to a load. The controller may include a power controller. The controller may be adapted to receive an electrically coupling of an additional photovoltaic module to the input, wherein the additional photovoltaic module is configured to provide an additional energy. The controller may be adapted to receive an electrically coupling of a refrigerator to the output. The controller may be adapted to control a power supplied by the output to the refrigerator, in accordance to the additional energy provided by the additional photovoltaic module, for example, via the power controller.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] In the following description, various embodiments of the present disclosure are described with reference to the following drawings, in which:

[0008] Fig .1 shows a schematic of a solar home system 100 according to the state of the art, including an existing photovoltaic module 120, a rechargeable battery 130, and a controller 110;

[0009] Fig.2 shows a schematic of a solar home system 100 as in Fig.1 , but wherein a refrigerator 240 has been connected to, in accordance to various embodiments;

[0010] Fig.3 shows a schematic of a solar home system 100 as in Fig.2, according to some embodiments, wherein the controller may include a power controller 150 for controlling a power supplied by the output 142 to the refrigerator 240; [0011] Fig .4 shows a schematic of a solar home system 100 as in Fig.2, according to some embodiments, wherein the controller may include a power controller 250 for controlling a power supplied by the output 142 to the refrigerator 240.

DETAILED DESCRIPTION

[0012] The following detailed description describes specific details and embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and changes may be made without departing from the scope of the invention. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0013] Features that are described in the context of an embodiment may correspondingly be applicable to the same or similar features in the other embodiments. Features that are described in the context of an embodiment may correspondingly be applicable to the other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and/or combinations and/or alternatives as described for a feature in the context of an embodiment may correspondingly be applicable to the same or similar feature in the other embodiments. Various embodiments describe features of the controller within the context of the method, such features may be correspondingly applicable to the controller without necessarily requiring the features of the method, and vice-versa.

[0014] The invention illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising”, “including,” containing”, etc. shall be read expansively and without limitation. The word "comprise" or variations such as "comprises" or "comprising" will accordingly be understood to imply the inclusion of a stated integer or groups of integers but not the exclusion of any other integer or group of integers. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by exemplary embodiments and optional features, modification and variation of the inventions embodied herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention.

[0015] The reference signs included in parenthesis in the claims are for ease of understanding of the invention and have no limiting effect on the scope of the claims.

[0016] Fig .1 shows a schematic of a solar home system 100 according to the state of the art, including an existing photovoltaic module 120, a rechargeable battery 130, and a controller 110. The controller 110 includes an input 112 configured to receive energy generated by the existing photovoltaic module; a battery terminal 132 configured to be electrically connected to the rechargeable battery, and an output 142 configured to be electrically coupled to a load 140.

[0017] Fig.2 shows a schematic of a solar home system 100 as in Fig.1 , but wherein a refrigerator 240 has been connected to, in accordance to various embodiments.

[0018] According to various embodiments, connecting the refrigerator 240 to the solar home system 100, may include electrically coupling an additional photovoltaic module 220 to the input 112 of the controller 110. The additional photovoltaic module 220 may provide an additional energy. The additional photovoltaic module 220 may be dimensioned so that the additional energy, e.g. over a certain period of time, is sufficient to power the refrigerator, for example, such that the original capacity of the solar home system 100 for powering the load 140 is not affected.

[0019] It may be provided that the rechargeable battery 130 of the solar home system 100 is sufficiently dimensioned, such that the additional capacity may be used for storing charge for the refrigerator 240. [0020] It may be provided that the controller 110 is sufficiently dimensioned for being able to handle the additional power supplied from the additional photovoltaic module and the additional power consumed by the refrigerator.

[0021] According to various embodiments, connecting the refrigerator 240 to the solar home system 100, may include electrically coupling the refrigerator 240 to the output 142. The refrigerator 240 may be electrically coupled to the existing load circuit, for example to the same terminal as the load 140, or to a dedicated terminal, which may be configured to operate the refrigerator 240, as will be explained further below.

[0022] According to various embodiments, connecting the refrigerator 240 to the solar home system 100, may include enabling a power controller for controlling a power supplied by the output 142 to the refrigerator 240. The power controller may be internal to the controller 110, e.g. pre-existing, or may be added as an external component as will be explained further below.

[0023] According to various embodiments, connecting the refrigerator 240 to the solar home system 100, may include controlling the power supplied by the output 142 to the refrigerator 240, in accordance to the additional energy provided by the additional photovoltaic module 220, via the power controller. The power controller may control, for example limit, the power supplied to the refrigerator 240, for example so that only the additional energy, e.g. stored as additional charge in the rechargeable battery 130, may be used to power the refrigerator 240.

[0024] According to various embodiments, a refrigerator and an additional photovoltaic module may be added to an existing solar home system, wherein no or only a few additional components may be provided. For example, no additional components may be provided if the rechargeable battery is sufficiently dimensioned, and the power controller is an integrated power controller integrated in the controller.

[0025] According to various embodiments, the refrigerator may be an electrical refrigerator, for example an off-grid solar refrigerator. For example, the refrigerator may be configured to operate with the voltage level of a solar home system. For example, the refrigerator may be a compression refrigerator. [0026] According to various embodiments, the expression “electrically coupling the refrigerator to the output” may mean connecting a power inlet of a refrigerator to the output of the controller, such that the refrigerator is“powered” once the output of the controller supplies the provided power.

[0027] The invention, according to various embodiments, may provide a retrofit integration of a refrigerator to an existing solar home system.

[0028] The provision of the additional photovoltaic module may provide surplus of additional energy which is not consumed by the refrigerator, for example during peak consumption time of the load the load may benefit from the additional energy if the refrigerator is off, since a refrigerator’s power consumptions cycles over time. Fig.3 shows a schematic of a solar home system 100 as in Fig.2, according to some embodiments, wherein the controller may include a power controller 150 for controlling a power supplied by the output 142 to the refrigerator 240. The power controller 150 may be pre-existing in the controller, or the method of connecting the refrigerator 240 to the solar home system 100 may include adding at least part of a power controller 150 to the controller 110.

[0029] As illustrated in Fig.3, and according to some embodiments, the power controller 150 may be an integrated power controller 150, integrated in the controller 110, and the step of enabling a power controller may include reconfiguring the controller 110, e.g. by configuring the software and/or the hardware. The term“software” as used herein includes“firmware”.

[0030] Fig .4 shows a schematic of a solar home system 100 as in Fig.2, according to some embodiments, wherein the controller may include a power controller 250 for controlling a power supplied by the output 142 to the refrigerator 240. As illustrated in Fig.4, and according to some embodiments, the power controller 250 may be an external power controller 250, which may be external to the controller 110. The method of connecting the refrigerator 240 to the solar home system 100 may include electrically coupling the external power controller 250 in series between the output 142 and the refrigerator 240. According to some embodiments a communication link may be established between the controller 110 and the power controller 250. [0031] According to some embodiments, with the proviso of an external power controller, changes to the controller may not be required.

[0032] According to various embodiments, the method for connecting the refrigerator to a solar home system, may further comprise the step of providing a load measurement circuit configured to measure the power load of the refrigerator. This step may include adding an external load measurement circuit or configuring an existing load measurement circuit. According to some embodiments, the existing load measurement circuit may be an integral part of the power controller. Also, electrically coupling the external power controller in series between the output and the refrigerator may be carried out together with adding an external load measurement circuit if these are part of a same device including common electrical terminals.

[0033] According to some embodiments, wherein a load measurement circuit is provided, the load measurement circuit may measure a current, the current supplied to the refrigerator, via a series shunt resistor. The series shunt resistor is of known resistance. The power consumed by the refrigerator may be essentially be linearly dependent of the current supplied to the refrigerator, since the voltage is more or less constant and known. For increasing precision, the voltage, with which the refrigerator is powered may be measured and thus the power consumed by the refrigerator may be calculated. The energy consumed by the refrigerator over a certain period of time may be calculated from the power.

[0034] According to various embodiments, the method for connecting the refrigerator to a solar home system, may further comprise the step of monitoring a power balance between an integral of the additional energy and an integral of the power load of the refrigerator. The power balance may be the difference between an integral of the power provide by the additional photovoltaic module (e.g. the additional energy) and an integral of the power load of the refrigerator. The integral may over a fixed period of time, for example daily starting at pre- defined day time. Alternatively or in addition, the integral may be a rolling integral. Other calculated electric measures may be used instead of integrals, for example the averages. [0035] According to various embodiments, the power controller may be configured to carry out the step of monitoring the power balance.

[0036] According to various embodiments, the power controller may be configured to control, for example limit, the power supplied to the refrigerator in accordance to the power balance and/or a predicted power balance.

[0037] According to various embodiments, the power controller may be configured to control the power supplied to the refrigerator in accordance to a battery voltage.

[0038] According to various embodiments, the power controller may be configured to control the power supplied to the refrigerator in accordance to a charge determined or predicted by a weather data. The weather data may include the time that the solar illumination intensity is above a certain level during a fixed period of time.

[0039] According to some embodiments, the time that the solar illumination intensity is above a certain level may be at least partially calculated as the total time, during a fixed period of time, in which an electrical parameter, indicative of solar illumination intensity, of the additional photovoltaic module is above a pre- determined threshold. For example, for a day, the time that the solar illumination intensity is above a certain level may be the sum of the time that the power produced by the additional photovoltaic module is above a certain threshold, e.g. above 0.5 the power capable of being produced under full sun illumination. Examples of an electrical parameter of the additional photovoltaic module, indicative of solar illumination intensity are: the voltage; the power at the maximum power point; the current at the maximum power point; the short circuit current; or a parameter calculated from one or more of the preceding.

[0040] According to some embodiments, the time that the solar illumination intensity is above a certain level may be at least partially calculated as the total time, during a fixed period of time, in which the charging voltage of the rechargeable battery is above a pre-determ ined threshold.

[0041] According to some embodiments, the weather data may be obtained remotely, optionally via an internet connection. [0042] According to various embodiments, the power controller may be configured to control the power supplied to the refrigerator between on and off states in accordance to a pre-determ ined time schedule.

[0043] Thus, hardware can be saved when connecting the refrigerator to an existing solar home system, according to various embodiments. In some embodiments and examples given herein, no additional controller or battery are needed, in other embodiments and examples given herein, the addition of an external power controller may be sufficient.

Claims

1. A method (1 ) for connecting a refrigerator (240), with a refrigerator power load, to a solar home system (100), the solar home system (100) comprising an existing photovoltaic module (200), a rechargeable battery (130), and a controller (110), the controller (110) comprising:

an input (112) configured to receive energy generated by the existing photovoltaic module (120);

a battery terminal (132) configured to be electrically connected to the rechargeable battery (130);

an output (142) configured to be electrically coupled to a load (140);

wherein the method (1 ) comprises the steps of:

- electrically coupling an additional photovoltaic module (220) to the input (112) of the controller (110), wherein the additional photovoltaic module (220) is configured to provide an additional energy;

- electrically coupling the refrigerator (240) to the output (142);

- enabling a power controller (150, 250) for controlling a power supplied by the output (142) to the refrigerator (240);

- controlling the power supplied by the output (142) to the refrigerator (240), in accordance to the additional energy provided by the additional photovoltaic module (220) via the power controller (150, 250).

2. The method (1 ) according to claim 1 , wherein the power controller (150, 250) is an integrated power controller (150) integrated in the controller (110), and wherein the step of enabling a power controller comprises reconfiguring the controller (110).

3. The method (1 ) according to claims 1 or 2, wherein the power controller (150, 250) is an external power controller (250) which is external to the controller (110), and wherein the method further comprises: electrically coupling the external power controller (250) in series between the output (142) and the refrigerator (240).

4. The method (1 ) according to any of the previous claims, further

comprising the step of: providing a load measurement circuit configured to measure the power load of the refrigerator (240), comprising adding an external load measurement circuit or configuring an existing load measurement circuit. 5. The method (1 ) according to any of the previous claims, wherein the existing load measurement circuit is an integral part of the power controller (150, 250).

6. The method (1 ) according to any of the previous claims, further

comprising the step of: monitoring a power balance between an integral of the power provided by the additional photovoltaic module and an integral of the power load of the refrigerator (240).

7. The method (1 ) according to any of the previous claims, wherein the power controller (150, 250) is configured to carry out the step of monitoring the power balance.

8. The method (1 ) according to any of the previous claims, wherein the power controller (150, 250) is configured to control the power supplied to the refrigerator (240) in accordance to the power balance and/or a predicted power balance.

9. The method (1 ) according to any of the previous claims, wherein the power controller (150, 250) is configured to control the power supplied to the refrigerator (240) in accordance to a battery voltage.

10. The method (1 ) according to any of the previous claims, wherein the power controller (150, 250) is configured to control the power supplied to the refrigerator (240) in accordance to a charge determined or predicted by a weather data.

11. The method (1 ) according to claim 10, wherein the weather data

comprises the time that the solar illumination intensity is above a certain level during a fixed period of time.

12. The method (1 ) according to claim 11 , wherein the time that the solar illumination intensity is above a certain level is at least partially calculated as the total time, during a fixed period of time, in which an electrical parameter, indicative of solar illumination intensity, of the additional photovoltaic module (220) is above a pre-determined threshold.

13. The method (1 ) according to claim 11 or 12, wherein the time that the solar illumination intensity is above a certain level is at least partially calculated by the time, during a fixed period of time, in which the charging voltage of the rechargeable battery (130) is above a pre-determined threshold. 14. The method (1 ) according to any of claims 11 to 13, wherein the weather data is obtained remotely, optionally via an internet connection.

15. The method (1 ) according to any of the previous claims, wherein the power controller (150, 250) is configured to control the power supplied to the refrigerator (240) between on and off states in accordance to a pre- determined time schedule.

16. A controller (110), optionally adapted for the method of any of the

previous claims, the controller comprising:

an input (112) configured to receive energy generated by an existing photovoltaic module (120); a battery terminal (132) configured to be electrically connected to a rechargeable battery (130);

an output (142) configured to be electrically coupled to a load (140);

a power controller (150, 250);

and adapted to:

- receive an electrical coupling of an additional photovoltaic module (220) to the input (112), wherein the additional photovoltaic module (220) is configured to provide an additional energy;

- receive an electrical coupling of a refrigerator (240) to the output

(142); and

- control a power supplied by the output (142) to the refrigerator (240), in accordance to the additional energy provided by the additional photovoltaic module (220) via the power controller (150, 250).