Title of Invention

"POWER-CUM-BATTERY OPERATED REFRIGERATOR"

Abstract

This invention relates to a power-cum-battery operated refrigerator characterised in that: (a) an inverter module (2) is provided which is fitted on the backside of refrigerator at base plate (5) wherein the said inverter module comprises a 12V DC, 120Ah inverter battery (3) connected to said inverter module via cables, a charger circuit (8) connected to main supply and providing a DC output of 12V with controlled current of 5-6 amperes to charge the said inverter battery during AC mains operations, a MOSFET switching circuit (9) providing an output of 12V, 50Hz, AC by converting 12V, DC power of said inverter battery to AC supply when there is failure of AC mains supply; a step up transformer (10) connected to said MOSFET switching circuit and adapted to step up the 12V, 50Hz, AC output of said MOSFET circuit to 240V, 50Hz, AC, a feed back circuit (11) connected to said step up transformer which is adapted to regulate the voltage within 180 to 240V by controlling the dwell angle of the MOSFET switching, and a double pole change over relay (12), (b) a CSR (capacitor start and run) type, reciprocating compressor (7) is provided which is adapted to take start even at low voltage and run at good power factor with the help of run capacitor such as herein described; (c) a start capacitor (1) is provided which is connected in series with said CSR compressor. (

Full Text

FIELD OF INVENTION This invention relates to power-cum-battery operated refrigerator. PRIOR ART A refrigerator usually runs on main power supply. If the power supply is interrupted, cooling inside the refrigerator is not guaranteed any longer. In case of long power cuts, the food inside the refrigerator will get spoiled. According to US Patent No. 4216385, an AC/DC power supply device is known for operating a refrigerator compressor which switches over from AC operation mode AC to DC operation mode from a DC power source, through an inverter circuit. A thermostat is provided which is connected to a circuit for supplying DC voltage to the inverter circuit in the DC operation mode and a switching section is provided so that high potential points including the potential of AC power source and low potential points including the potential of DC power source do not face each other in close vicinity to prevent the AC power voltage from being unwantedly applied to the low voltage side. US Patent No. 3974660 discloses a battery powered inverter power supply for recreational vehicle refrigeration units or the like which is adapted to operate in a DC mode wherein power is supplied to the inverter and refrigeration unit from a vehicle battery and in an AC mode wherein power is supplied to the refrigeration unit from a source of normal household power. A cold control circuit is responsive to a thermostatic sensor within the refrigerated enclosure to apply battery power to the inverter power supply only when the supply is operating in the DC mode and cooling is required. A battery charger is operable during the AC mode to automatically recharge the vehicle battery. US Patent No. 4015182 discloses a refrigeration system driven by an electronically commutated DC motor for circulating a suitable coolant through a condenser then through an evaporator disposed within a chamber or compartment to be cooled. The system is used in portable refrigerating apparatus in recreational vehicles, refrigeration apparatus for trucks or other transport vehicles and for air conditioning system for automobiles and recreational vehicles. In such applications, a power source such as battery, alternator or a generator serves to energise the motor. The motor may be operated by an electronic commutating circuit responsive to the position of the rotor of the DC motor for efficiently commutating the energizing signals applied to the stator windings of he brushless DC motor. The level of energization is set in accordance with the desired temperature to be maintained by the refrigeration system, whereby the DC motor is energized to drive the compressor at a selected speed corresponding to the desired temperature. The degree of stator energization may be controlled by regulating the output of the power source, or by regulating directly the commutating circuit to control the current signals applied to the stator windings. OBJECTS OF THE PRESENT INVENTION An object of the present invention is to provide a refrigerator which will operate on regular main power supply as well as on battery. Another object of the present invention is to provide a refrigerator wherein compressor and bulb will run even in case of low voltage less than 165 volts or high voltage more than 255 volts. In such cases the system will switch over automatically from AC supply to DC supply. Still another object of the present invention is to provide a refrigerator which incorporates an electronic PCB which transforms battery DC voltage into AC suitable for household refrigerator compressors. Further object of the present invention is to provide a refrigerator which incorporates an electronic PCB which enables automatic switch over from DC to AC supply when regular AC supply becomes available. STATEMENT OF INVENTION According to this invention there is provided a power-cum-battery operated refrigerator characterised in that: (a) an inverter module is provided which is fitted on the backside of refrigerator at base plate wherein the said inverter module comprises a 12V DC, 120Ah inverter battery connected to said inverter module via cables, a charger circuit connected to main supply and providing a DC output of 12V with controlled current of 5-6 amperes to charge the said inverter battery during AC mains operations, a MOSFET switching circuit providing an output of 12V, 50Hz, AC by converting 12V, DC power of said inverter battery to AC supply when there is failure of AC mains supply; a step up transformer connected to said MOSFET switching circuit and adapted to step up the 12V, 50Hz, AC output of said MOSFET circuit to 240V, 50Hz, AC, a feed back circuit connected to said step up transformer which is adapted to regulate the voltage within 180 to 240V by controlling the dwell angle of the MOSFET switching, and a double pole change over relay, (b) a CSR (capacitor start and run) type, reciprocating compressor is provided which is adapted to take start even at low voltage and run at good power factor with the help of run capacitor such as herein described; (c) a start capacitor is provided which is connected in series with said CSR compressor. DESCRIPTION OF FIGURES The invention is illustrated with accompanying drawings which are intended to illustrate an embodiment of the present invention. These drawings are not intended to be taken restrictively to imply any limitation on the scope of the present invention. In the accompanying drawings:- Fig. 1: shows the rear-view of refrigerator; Fig. 2: shows the block diagram of inverter circuitry DESCRIPTION OF INVENTION W.R.T. DRAWINGS Referring to fig.l, the invention relates to a refrigerator which runs on regular household supply as well as on battery. The cooling of eatables kept inside the refrigerator is therefore ensured even during power cuts. Besides the conventional parts of the refrigerator namely a cabinet, a freezer compartment, a thermostat, a door, a health guard which protects food in the refrigerator from bad odour in case of door of the refrigerator remaining closed for long time, the refrigerator of the present invention incorporates a start capacitor (1) which helps the CSR (capacitor start run) compressor (7) during start by providing more torque and reducing current. This results in less burden on inverter leading to an easy start. It is connected with said CSR compressor in series with start winding. An inverter module (2) is fitted on the backside of the refrigerator at base plate (5) where said inverter module as well as the said compressor are fitted. The main function of the said inverter module is to convert 12 VDC power from battery to 240V 50Hz AC power to drive the refrigerator in case of power failure or power cuts. The said inverter module contains high and low voltage cards inside together with a serviceable fuze lying inside battery terminal cover. The inverter module is based on micro-controller, which has been specially designed for refrigerator applications. Also MOSFET are used inside the inverter for switching. It has an inbuilt battery charger using 15UF capacitor for limiting the current. A 4-pin connector is provided in front of the inverter module for interfacing with the mains power input and output the thermostat and bulb inside the refrigerator. Three LED indications are provided to indicate the present status of the inverter module and also for trouble-shooting and debugging for service person. A 12, 120Ah battery (3) is provided aside the refrigerator. It is connected to said inverter module via Red and Black colour cables provided with the refrigerator. The cable end that is to be indicated with battery and inverter is indicated by using stickers. A power cord harness (4), which is a three pin plug power cord harness is fitted on the rearsides of the refrigerator, which interfaces the said inverter module with refrigerator and also interfaces bulb, thermostat and the said CSR compressor. A PTC (positive temperature co-efficient) relay and over-load protector (OLP) (6) is used for the refrigerator. The said over-load protector (OLP) is connected in series and protects the compressor from sudden high voltage, current or temperature. The PTC relay and over-load protector are together filled with the said CSR compressor. PTC also acts as current limiter to CSR compressor incase of lock rotor condition. The CSR compressor (7) is fitted to the said base plate (5) at the bottom of backside of the refrigerator. Basically it is CSR (capacitor start and run) type, reciprocating compressor which pumps the refrigerant in cooling system tubes. The compressor is adapted to be able to take start even at low voltage and run at good power factor with the help of run capacitor. The run capacitor (13) is connected with CSR compressor to improve the power factor of compressor load. This reduces the total current flowing from inverter and results into reduction of power losses in inverter thereby the efficiency of the system improves. It gives more back up time on battery mode. Referring to fig.2, the main supply is connected to charger circuit (8). The charger circuit provides a DC output of 12V with 5-6 amperes controlled current to charge the investor battery (3) during AC mains operation. In case of AC mains failure, the DC power stored in the battery is converted to AC by MOSFET switching circuit (9). The output of the said MOSFET switching circuit is 12V, 50Hz AC. This AC output goes to step up transformer (10) which steps up the output of MOSFET circuit from 12V to 240V, 50 Hz AC. There is a feedback circuit (11) to said MOSFET circuit (9). This feedback circuit provides signals to MOSFET switching circuit to regulate the output voltage within the 180 to 240V by controlling the dwell angle of the MOSFET switching. The regulated AC supply is connected to the refrigerator through a double pole change over relay (12) which connects the load to the regulated AC output during AC mains failure when AC main supply is available, this relay disconnects the refrigerator from the investor output supply and connect to AC mains. It is to be understood that the system of present invention is susceptible to modifications, changes and adaptations by those skilled in the art. Such modifications, changes and adaptations are intended to be within the scope of the present invention, which is further set forth under the following claims: WE CLAIM; 1. A power-cum-battery operated refrigerator characterised in that: (a) an inverter module (2) is provided which is fitted on the backside of refrigerator at base plate (5) wherein the said inverter module comprises a 12V DC, 120Ah inverter battery (3) connected to said inverter module via cables, a charger circuit (8) connected to main supply and providing a DC output of 12V with controlled current of 5-6 amperes to charge the said inverter battery during AC mains operations, a MOSFET switching circuit (9) providing an output of 12V, 50Hz, AC by converting 12V, DC power of said inverter battery to AC supply when there is failure of AC mains supply; a step up transformer (10) connected to said MOSFET switching circuit and adapted to step up the 12V, 50Hz, AC output of said MOSFET circuit to 240V, 50Hz, AC, a feed back circuit (11) connected to said step up transformer which is adapted to regulate the voltage within 180 to 240V by controlling the dwell angle of the MOSFET switching, and a double pole change over relay (12), (b) a CSR (capacitor start and run) type, reciprocating compressor (7) is provided which is adapted to take start even at low voltage and run at good power factor with the help of run capacitor such as herein described; (c) a start capacitor (1) is provided which is connected in series with said CSR compressor. 2. A power-cum-battery operated refrigerator as claimed in claim 1 wherein a positive temperature co-efficient (PTC) relay and overload protector (OLP) (6) is provided which is connected in series. 3. A power-cum-battery operated refrigerator as herein described substantially and illustrated with accompanying drawings.

Documents:

1507-del-2003-abstract.pdf

1507-del-2003-claims.pdf

1507-del-2003-correspondence-others.pdf

1507-del-2003-correspondence-po.pdf

1507-del-2003-description (complete).pdf

1507-del-2003-drawings.pdf

1507-del-2003-form-1.pdf

1507-del-2003-form-19.pdf

1507-del-2003-form-2.pdf

1507-del-2003-form-3.pdf

1507-del-2003-form-5.pdf

1507-del-2003-gpa.pdf

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