Title of Invention

"AN AIR CONDITIONER SYSTEM OPERABLE ON A D.C. POWER SOURCE"

Abstract This invention relates to an improved air conditioner system operable on a D.C. power source comprising atleast a first inverter (I) for supplying A.C. power to a blower motor and atleast a second inverter (II) for supplying A.C power to the compressor and fan motor for the condenser wherein each of said inverters is connected to the d.c. power source and a current protection circuit (2), a temperature control unit (13) connected to a temperature sensor (14) and inner connected with LCD display unit (3) and RS 232 interface (4).
Full Text FIELD OF INVENTION
This invention relates to an air conditioner system operable on a d.c. power source. In particular, though not limited thereto, the airconditioner system of the present invention may be used in the driver's cabin of a locomotive or any rolling stock.
PRIOR ART
Normal inverter used for supplying AC power to an air-conditioner from a DC source switches on and produces AC power on a continuous basis. The blower is switched on through an electromagnetic switch (contactor). The compressor and condenser fan are switched on through other electromagnetic switch (contactor) as per the requirement of cooling by temperature controller. If the temperature in the room rises, the blower continues to run but the compressor and condenser fan are switched on. When the set point of the temperature controller in the room is reached due to drop in temperature the compressor and condenser fan are switched off. When the temperature rises again above the set point of the controller, the compressor and condenser switch on again and thus the compressor and condenser fan continue to cycle on and off to maintain the room temperature. In winter, compressor and condenser fan are kept switched off with blower running continuously. The heaters are switched on and off through

electromagnetic switch (contactor) to heat the room as per the requirement of the temperature controller set point.
Using conventional inverter system the large inverter (capable of running compressor, condenser fan and blower) remains on whether compressors are on and off. Even for ventilation (circulation of air in the room when no heating and cooling is required), the large inverter remains on to supply power to a relatively much smaller motor of the blower. The switching on and off of the blower, compressor and condenser fan is done through electromagnetic switching devices (contactors).
Thus, air conditioning systems operable from a d.c. power are known in the art. However, such systems generally employed electromagnetic switches resulting in failure of the system due to rapid wear and tear of the electromagnetic and switching parts employed in the system.
OBJECTS OF THE INVENTION
An object of this invention is to propose an improved air conditioning system operable on a d.c. power source.

Another object of this invention is to propose an improved air conditioner system operable on a D.C. power source, which no longer incorporate electromagnetic switches and thereby reduces failure of the system.
Still another object of this invention is to propose an improved air conditioner system operable on a D.C. power source, which reduces power consumption.
Yet another object of this invention is to propose an improved air conditioner system operable on a D.C. power source, which minimizes on wear and tear.
A further object of this invention is to propose An improved air conditioner system operable on a D.C. power source, which is compact and light weight.
Further objects and advantages of this invention will be more apparent from the ensuing description.
STATEMENT OF THE INVENTION
According to this invention there is provided an improved air conditioner system operable on a D.C. power source characterized in that atleast a first inverter for supplying A.C power to a blower motor and atleast a second inverter for supplying A.C. power to the compressor and fan motor for the condenser wherein each of said inverters is connected to the d.c. power source and a current protection circuit, a temperature

control unit connected to a temperature sensor and inner connected with LCD display unit, and RS 232 interface.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING;
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawing and wherein:
Fig. 1 shows: Improved Air conditioner system of the present invention.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWING:
According to this invention, there is provided an air conditioner system provided with two-in-one inverter which is a device having two inverters on one chassis. Such type of inverters are required for operation for Air-conditioners on DC power supplies. In an air-conditioner, the blower motor runs continuously. The compressor and condenser fan switches on and off according to the need for cooling. During winter for heating, the blower continues to run and compressor remains off but instead heaters are switched on and off according to the need for heating. Now reference is made to fig. 1

The an air-conditioning system operable on a d.c. power source comprising :-(i) atleast a first inverter (1) for supplying a.c. power to the blower motor, (ii) atleast a second inverter (2) for supplying a.c. power to the compressor and fan
motor for the condenser, (iii) each of said inverters adapted to be connected to a d.c. power source, (iv) a current protection circuit for each of said inverters connected to the output of its
respective inverter, (v) a control unit having a controller connected to the air conditioning operating
circuit. In accordance with this invention the air conditioning operating circuit (2) is capable of providing a three phase low voltage a.c. power source to the load and comprises a protection circuit to check the input d.c. voltage polarity and the presence of any excess current.
The output from the protection circuit is connected to a first inverter for feeding an a.c. power to the motor of the blower. The protection circuit is also connected to a second inverter for feeding a.c. power to the compressor and fan motor of condenser, each through said current protection circuit.
Each of the inverters comprises a converter connected to the output of circuit. The converters provide a steady low voltage. The converter (11, 12) is connected to its

respective central processing unit (5, 8), which is microprocessor, and the output is applied to an isolated gate bipolar junction transistor or to a switching circuit.
A sensing unit (6, 9) provides feed back to the central processing unit (5, 8) to control the output of the respective IGBT (7, 10).
The output of each IGBT is applied to its respective motor through its current protection circuit.
A heater is provided with the system and is adapted to be directly connected to the power source. During the period that the heater is activated, the second inverter is in an off position or mode.
The system further comprises a control unit connected to the air conditioning operating circuit to provide safety protections, indications of on and fault conditions, alarms and communication to a PC through an interface.

SEQUENCE OF OPERATION
DC power source is switched ON.
Reverse polarity protection unit checks the polarity only if the polarity is
OK DC supply to the power supply unit is switched ON.
Converter -1 is ON, switching ON the inverter-1 Unit which provides
supply to the Blower motor.
Sensing unit -1 provides the Voltage and Current feed back to CPU for
maintaining the correct Voltage and checking for High Current/Single
phasing routinely.
Temperature Control Unit (13) senses the temperature through the Sensors
(14) inside the AC unit. It gives the command to Inverter-2 unit for
compressor and condenser motor operation if cooling is required and
switches ON the Heater relay (15) if heating is required.
When the inverter-2 is ON sensing unit-2 keeps a watch on Correct
Voltage, HP/LP, Excess Current, Single phasing in compressor and correct
voitage, excess current, single phasing in condenser motoT.
Excess DC current protection unit (2) provides safety in case of high DC
current.

LCD display (3) is provided to Display the operating condition and fault
conditions.
RS-232 interface (4) is provided to fault display and fault eradication
purpose by manually operating the AC unit for servicing. This also has
features to display or Log the operating conditions and fault conditions.
CPU (5) receives all the sense feedback data from sensing unit (6) and
regulates the switching of the IGBT (7) to maintain the constant operating
voltage.
CPU also switches off switching if the current, or DC voltage is Out of
Limit.
CPU sends the data to be displayed on the display unit.
The system of the present invention is disposed with the two-in-one inverter having one small inverter to operate the blower and one large capacity inverter for compressor and condenser fan. The smaller inverter remains on all the time to make the blbwer run continuously. The second larger inverter switches on only when temperature controller in the room calls for cooling to switch on the compressor and condenser fan. Further, both inverters are designed to provide a soft start i.e. voltage: and frequency increase from zero

to full gradually by maintaining a relationship between the voltage and frequency to provide smooth start of the motor from nil speed to full speed. This process does not require very heavy inrush currents to start the motor.
When a motor is started high inrush current (six time running current) is required to start the motor which puts stress on the power supply system as well as on the batteries which are providing the DC power. This phenomenon of surge in the DC source produces ripples in the DC power supply which causes reduction in life of the batteries due to jerks in the demand for power supply. With the soft start the voltage and frequency is increased slowly, therefore, the motor never draws more current than it requires to run at full speed. Therefore, there are no surges or jerks during start-up.
In a soft start system the motor is connected directly to the output of the inverter and no electromagnetic switching devices (contactors) are required. This reduces the number of components (contactors) which increases reliability, efficiency and reduction in cost at reduced power consumption. The compressor, condensers fan motor and blower motor are connected directly to the output of their respective inverter thus eliminating the contactors and potential failing devices.

The salient features of the Present invnetion
1. Less power consumption and high efficiency.
2. No contactors for compressor, condenser fan motor and blower fan motor for switching.
3. No surges in the DC supply source due to solid state switching on inverter causing ripple.
4. Increased battery life due to less ripples in the DC source.
5. Longer Battery Back-up Time since the larger inverter remains off when compressor and condenser motor are not required to run.
6. Economical operation due to reduced components.
7. Cost saving due to reduced materials (contactors wiring).
8. No cooling fans required in inverters.
9. HP trip indication (cooling stopped due to condenser block)
10. LP trip indication (Loss of gas)
11. High and low DC indication and protection.
12. High temperature protection for switching devices.

13. Reverse polarity protection for DC supply
14. Output fail and earth fault protection.
15. User indication and thermostat included.
Inverter I for blower provides soft start to motor, overload, single phasing protection and runs on all modes.
Inverter II for compressor provides soft starting features, overload, single phasing protection, and runs on cool mode.
It is to be understood that the process of the present invention is susceptible to modifications, adaptation, changes by those skilled in the art. Such modification, changes, adaptations are intended to be within the scope of the present invention, which is set forth under the following claims :-


WE CLAIM;
1. An improved air conditioner system operable on a D.C. power source characterized in that atleast a first inverter for supplying A.C power to a blower motor and atleast a second inverter for supplying A.C. power to the compressor and fan motor for the condenser wherein each of said inverters is connected to the d.c. power source and a current protection circuit, a temperature control unit connected to a temperature sensor and inner connected with LCD display unit, and RS 232 interface.
2. An improved air conditioner system operable on a D.C. power source as claimed in claim 1 wherein each of the said inverters comprises a converter connected to the output of said protection circuit.
3. An improved air conditioner system operable on a D.C. power source as claimed in claim 2 wherein the converter is connected to its respective central processing unit provided with the feed back from the respective sensing unit to control the output of the respective IGBT.
4. An improved air conditioner system operable on a D.C. power source as claimed in claim 3, wherein the output of the said IGBT is connected to its respective motor through its current protection circuit.
5. An improved air conditioner system operable on a D.C. power source as claimed in claim 1, wherein the temperature control unit is connected with a heater relay provided in the air-conditioner unit.

6. An improved air conditioner system operable on a D.C. power source as claimed in claim 5, wherein the heater relay is connected to a heating unit and the interface is provided between the temperature control unit and LCD display unit.
7. An improved air conditioner system operable on a D.C. power source as claimed in claim 1, wherein the temperature sensor is provided in the air conditioning unit.
8. An improved air conditioner system operable on a D.C. power source substantially as herein described with reference to drawing.

Documents:

577-DEL-2004-Abstract-(07-05-2008).pdf

577-del-2004-abstract.pdf

577-DEL-2004-Claims-(07-05-2008).pdf

577-del-2004-claims.pdf

577-DEL-2004-Correspondence-Others-(07-05-2008).pdf

577-del-2004-correspondence-po.pdf

577-del-2004-correspondence.pdf

577-DEL-2004-Description (Complete)-(07-05-2008).pdf

577-del-2004-description (provisional).pdf

577-del-2004-description.pdf

577-DEL-2004-Drawings-(07-05-2008).pdf

577-DEL-2004-Drawings-(15-04-2009).pdf

577-del-2004-drawings.pdf

577-DEL-2004-Form-1-(07-05-2008).pdf

577-del-2004-form-18.pdf

577-DEL-2004-Form-2-(07-05-2008).pdf

577-DEL-2004-Form-3-(07-05-2008).pdf

577-del-2004-form1.pdf

577-del-2004-form2 (provisional).pdf

577-del-2004-form2.pdf

577-del-2004-form26.pdf

577-del-2004-form4.pdf

577-del-2004-form5.pdf

577-DEL-2004-GPA-(07-05-2008).pdf


Patent Number 235194
Indian Patent Application Number 577/DEL/2004
PG Journal Number 31/2009
Publication Date 31-Jul-2009
Grant Date 27-Jun-2009
Date of Filing 24-Mar-2004
Name of Patentee SHERJANG SINGH SIDHU
Applicant Address Plot 23, Sector 6, Faridabad, Haryana, INDIA
Inventors:
# Inventor's Name Inventor's Address
1 SHERJANG SINGH SIDHU Plot 23, Sector 6, Faridabad, Haryana, INDIA
2 RONSHER SINGH SIDHU Plot 23, Sector 6 Faridabad
PCT International Classification Number F28D 5/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA