DESC:FIELD OF INVENTION
The present invention relates to a charging system that is used for various applications. More specifically, the present invention relates to an electronic charging system for enhancing the performance and safety of a storage device or for feeding power directly to a load using an inverter. The electronic charging system is managed by a central control unit for choosing one or more sources of energy based on a user determined set level. Further, the system is provided with a switching mechanism that eliminates sparking across a switch/relay, extends life and also enhances product safety.

BACKGROUND OF INVENTION
Generally, electronic charging device charges a storage device such as a battery or directly feed power to a load using an inverter by means of anyone of the sources of energy like power grid, wind, solar etc. Interruption of any of those energy sources leads to the failure of the battery charging and after emptying the reserved battery charge, power failure occurs. So, there is a need of a charging device to identify anyone or combination of favourable source of energy and limit charging the battery (storage device) from a certain source or discharging the battery (storage device) beyond a certain point.

To identify the source or limit the charging from a source, is predicated by some of the parameters such as cost of the energy source, climatic conditions in case of renewable energy sources, etc. The toggling for the determined source of charging is done by an electro-mechanical switch, which is also termed as relay or contactor or any solid state device. Typically, they have a fixed life span which is provided in terms of their number of switching cycles. The repeated switching of the relay can cause plasma heating or electrical arcing, which produces sparks across the contacts. Therefore, this leads to the damage of the relay contacts or may also weld the contacts together and finally, result in failure in both performance and safety measures of the electronic charging device.

Some of the prior arts are:
US20120267957 titled “TRANSFER SWITCH FOR AUTOMATICALLY SWITCHING BETWEEN ALTERNATIVE ENERGY SOURCE AND UTILITY GRID” teaches about an automatic transfer switch configured for connection to a non-traditional, full-time or intermittent power source, such as a wind turbine or solar panel, selectively connects the non-traditional power source as a primary power source and a utility-derived power source as a secondary power source.

884/DEL/2011 titled "AN IMPROVED SOLAR GRID HYBRID SUBSYSTEM USED WITH POWER BACKUP SYSTEMS" teaches about an solar grid hybrid subsystem for power backup system comprises contactor and interface circuitry configured to couple with a power bus of power backup system, backup system and battery connected to each other wherein, the power from photovoltaic array or AC grid is fed to the solar charge controller and backup system. User can configure the solar grid hybrid subsystem and set the priority of the source of the power as per the requirement.

Thus, there exists a need for a charging system that can identify anyone or combination of favourable source of energy and limit the amount of energy to be drawn from a particular source, maximize the use of a certain energy source and ensure the availability of energy on emergency demand irrespective of the source. Further, there is a need for a system that can eliminate problems associated with sparking.

OBJECTS OF INVENTION
One or more of the problems of the conventional prior art may be overcome by various embodiments of the system and method of the present invention.

It is the primary object of the present invention to provide an electronic charging system for enhancing the performance and safety of a storage device such as a battery or for feeding power directly to a load using an inverter.

It is another object of the present invention, wherein the electronic charging system is managed by a central control unit for choosing one or more sources of energy based on a user determined set level; said central control unit is driven by a microprocessor or a microcontroller. The power source includes power grid, renewable energy sources including solar, wind and combination thereof or non-renewable sources.

It is another object of the present invention, wherein the system is provided with a switching mechanism that eliminates sparking across a switch/relay, extends life and also enhances product safety.

It is another object of the present invention, wherein the advantages of the system are as follows:
(i) Allows users to combine sources of renewable energy with grid power.
(ii) Provides the ability to utilize the entire quantity of the renewable power source by smart usage of the reserve storage setting feature.
(iii) Allow users to enjoy long periods of faultless operation.
(iv) Provides full utilization of the installed renewable power systems.
(v) Provides availability of a part of the storage device to fill using renewable energy when the energy source becomes available.
(vi) Managing utilization of the grid power during off-peak hours only and therefore reducing amount and cost of power drawn from the grid.

SUMMARY OF INVENTION
Thus according to the basic aspect of the present invention there is provided an electronic charging system comprising of:
Central control unit for choosing one or more power sources of energy based on a user determined set level;
Sensor;
Storage device;
Switching mechanism; and
Inverter for feeding power directly to a load,
wherein the central control unit is connected to two or more of the power sources along with the storage device and the load,
wherein the sensor is connected to the storage device and output information is relayed to the central control unit, which determines and indicate State of Charge (SoC) and State of Health (SoH) of the storage device,
wherein toggling of one or more sources of power is achieved by the switching mechanism,
wherein the switching mechanism prevents sparking and thereby ensures that the switching happens at zero point of AC signal only, and
wherein the electronic charging system prevents one or more of designated charging sources to charge the storage device or provide power to the connected loads.

In the above, the power source includes power grid, renewable energy sources including solar, wind and combination thereof or non-renewable sources.
It is another aspect of the present invention, wherein the central control unit comprising of:
Main control unit; and
Charge control units,
wherein the main control unit selects the source of power used for charging the storage device or supply to the loads independently,
wherein the charge control unit regulates the power supplied to the storage device, and
wherein priority to charge the storage device will be with renewable energy sources only until the storage has reached set reserve level.

Also, in the above the switching mechanism is an electro-mechanical switch or relay or contactor or any solid state device.

It is another aspect of the present invention, wherein the sensor determines ambient temperature used to control the charging of the storage device.

It is another aspect of the present invention, wherein reserve storage setting (high and low for each energy source) of the storage device is used to limit the amount of energy to be drawn from a particular power sources, maximize the use of a certain power sources and ensure availability of power for emergency demand irrespective of the power source.

It is another aspect of the present invention, wherein the central control unit limits charging of the storage device from one or more of the power sources until the storage device has been discharged to a certain preset or user set limit but allowing other power sources to charge it beyond the preset or user-set limit and excess power is fed to the power grid.

It is another aspect of the present invention, wherein the central control unit limits charging level of the storage device from one or more of the power sources to a preset or user set value such that affected power sources will not be able to charge the storage device beyond the preset or user set limit but allowing other power sources to continue to charge the storage device.

It is another aspect of the present invention, wherein the system charges the storage device with all the power sources or restricts the charging only from the solar power or restricts the charging from the power grid to a certain level of storage and then continues to charge only from other renewable sources of power.

It is another aspect of the present invention, wherein the system would feed the power to the load from the next available power source to get uninterrupted power, during under and over voltage conditions and thereby protecting associated devices and connected loads.

BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1: Illustrates the schematic connections in the electronic charging system of the present invention
Figure 2: Is a graphical representation which shows that the relay will close or open only when AC signal passes through zero point.
Referring to Figure 1, the electronic charging system comprises of central control unit [1] for choosing one or more power sources [2] of energy based on a user determined set level; sensor [3]; storage device [4]; switching mechanism and inverter [5] for feeding power directly to a load [6]. The power source [2] includes power grid, renewable energy sources including solar, wind and combination thereof or non-renewable sources. The solar power is provided via photovoltaic panels of appropriate sizes, wind power may be supplied by turbines or any other power source such as a diesel generator may be used as a power source [2].

The central control unit [1] is driven by a microprocessor or a microcontroller and further comprises of main control unit; and charge control units for regulating power supplied to the storage device [4] for charging. The sensor [3] is connected to the storage device [4] and output information is relayed to the central control unit [1], which determines and indicate State of Charge (SoC) and State of Health (SoH) of the storage device [4] using a variety of factors such as but not limited to voltage, currents, temperature, charging rate, discharging rate etc. The sensor [3] can accurately determine the charging and discharging currents to and from the storage device [4] to an accuracy of within 1% of its full scale. The sensor [3] is also equipped to perform coulomb counting so that the charge into and discharge out of the storage device [4] is counted accurately for SoC calculations. The sensor [3] is also equipped with a temperature measurement capability that can determine ambient temperature used to control the charging of the storage device [4].

The central control unit [1] is connected to two or more of the power sources [2] for example to both grid power and other sources of power along with the storage device [4], said storage device [4] include battery. The main control unit selects the source of power [2] used for charging the storage device [4] or supply to the loads [6] based on an algorithm. The algorithm will select the source of power [2] to the load [6] as well as to the storage device [4] independently. For example a source of wind power may also be connected or both solar and wind power may be connected or even a diesel generator may be connected. For example, during the day when solar power is available, the central control unit [1] will continue to provide power to the loads [6] directly from the solar power. In the event there is excess generation over demand, the balance could be stored in the storage device [4] or fed to the grid power [2]. In cases where the demand exceeds the generation, the balance will be drawn from the storage device [4] to satisfy the demand. This continues to toggle until the storage device [4] has reached reserve storage. Once the reserve storage is reached, any further demand can be met through the other available sources, for example grid power or diesel power or any of the other sources [2] connected.

A few possibilities can be considered when such a situation is reached: (i) choosing to charge the storage device [4] with all the available sources of power [2] including grid power or (ii) restrict the charging only from the solar power or (iii) restrict the charging from the grid to a certain level of storage and then continue to charge only from other renewable sources of power.

The reserve storage setting (high and low for each energy source) of the storage device [4] is used to limit the amount of energy to be drawn from the particular power sources [2], maximize the use of a certain power sources [2] and ensure availability of power for emergency demand irrespective of the power source [2]. The reserve storage is of great benefit to users who does not use grid power [2] to charge the storage device [4] unless the storage device [4] reaches the reserve setting and if the other sources of power [2] are unavailable. This will ensure that the priority to charge the storage device [4] will be with renewable sources of power only until the storage has reached the set reserve level. Thus there will be a high and low reserve setting for each of the power sources that are connected to the system.

The electronic charging system prevents one of more of the designated charging sources to charge the storage device [4] or provide power to the connected loads [6]. The central control unit [1] manages by limiting the plurality of power sources [2] by employing a switching algorithm with intent to maximize and minimize the use of one or more of the power sources [2] which is as follows:
a) the central control unit [1] limits charging of the storage device [4] from one or more of the power sources [2] until the storage device [4] has been discharged to a certain preset or user set limit but allowing other power sources [2] to charge it beyond the preset or user-set limit.
b) the central control unit [1] limits charging level of the storage device [4] from one or more the power sources [2] to a preset or user set value such that the affected power sources [2] will not be able to charge the storage device [4] beyond the preset or user set limit but allowing other power sources [2] to continue to charge the storage device [4].
Table 1 explains various scenarios used for charging the storage device according to the present invention.

TABLE 1:
SCENARIO IF STORAGE IS GREATER THAN RESERVE IF STORAGE IS LESS THAN RESERVE
Minimal Usage During the day (keeping storage device reserve as low as possible) Renewable provides power to load and charges storage device to 100% with remaining power. Any excess over these can be fed to grid

MAINS Not Used Renewable power charges storage device. MAINS used for load
Maximum usage during the day (keeping storage device reserve at say 50%) Renewable source and energy stored in the storage device provides power to load simultaneously. MAINS Not Used and no power fed to grid Renewable energy charges storage device. MAINS used for load
Severe Load Shedding During the day (keeping storage device reserve high say 90%) Renewable energy power to load and charges storage device with remaining power. Renewable Energy, energy stored in the storage device provides power to LOAD
Night time (keeping storage device reserve at say 50%) Energy stored in the storage device provides power to load. MAINS Not Used MAINS Provides power to load and charges storage device
Severe Load Shedding During the night (keeping storage device reserve at say 90%) Energy stored in the storage device provides power to load Energy stored in the storage device provides power to load

Figure 2 illustrates the graphical representation, which shows that the relay will close or open only when AC signal passes through zero point. The toggling of the sources of power is achieved by the switching mechanism, which is an electro-mechanical device that is called a relay or by a solid state relay. The choice of the switching mechanism is determined by the application of use as well as the ratings. The repeated switching of the relay can cause plasma heating or electrical arcing. This can lead to damage of the relay contacts and may weld contacts together. The present invention will prevent sparking across the relays and ensure that the relay will close or open only when the AC signal passes through the zero point as shown in the said figure.

The system offers additional features such as protecting associated devices as well as the loads connected to the system from over voltage and under voltage from the line. During the under and over voltage conditions, the system would feed the power to the load from the next available source according to the priority sequence and the user get uninterrupted power. It will monitor and display different electrical parameters so that the user can be aware of the performance of the device.
,CLAIMS:1. An electronic charging system comprising of:
Central control unit [1] for choosing one or more power sources [2] of energy based on a user determined set level;
Sensor [3];
Storage device [4];
Switching mechanism; and
Inverter [5] for feeding power directly to a load [6],
wherein the central control unit [1] is connected to two or more of the power sources [2] along with the storage device [4] and the load [6],
wherein the sensor [3] is connected to the storage device [4] and output information is relayed to the central control unit [1], which determines and indicate State of Charge (SoC) and State of Health (SoH) of the storage device [4],
wherein toggling of one or more sources of power [2] is achieved by the switching mechanism,
wherein the switching mechanism prevents sparking and thereby ensures that the switching happens at zero point of AC signal only, and
wherein the electronic charging system prevents one or more of designated charging sources to charge the storage device [4] or provide power to the connected loads [6].

2. The electronic charging system as claimed in claim 1, wherein the power source [2] includes power grid, renewable energy sources including solar, wind and combination thereof or non-renewable sources.

3. The electronic charging system as claimed in claim 1, wherein the central control unit [2] comprising of:
Main control unit; and
Charge control units,
wherein the main control unit selects the source of power [2] used for charging the storage device [4] or supply to the loads [6] independently,
wherein the charge control unit regulates the power supplied to the storage device [4], and
wherein priority to charge the storage device [4] will be with renewable energy sources only until the storage has reached set reserve level.

4. The electronic charging system as claimed in claim 1, wherein the switching mechanism is an electro-mechanical switch or relay or contactor or any solid state device.

5. The electronic charging system as claimed in claim 1, wherein the sensor [3] determines ambient temperature used to control the charging of the storage device [4].

6. The electronic charging system as claimed in claim 5, wherein reserve storage setting (high and low for each energy source) of the storage device [4] is used to limit the amount of energy to be drawn from a particular power sources [2], maximize the use of a certain power sources [2] and ensure availability of power for emergency demand irrespective of the power source [2].

7. The electronic charging system as claimed in claim 6, wherein the central control unit [1] limits charging of the storage device [4] from one or more of the power sources [2] until the storage device [4] has been discharged to a certain preset or user set limit but allowing other power sources [2] to charge it beyond the preset or user-set limit and excess power is fed to the power grid.

8. The electronic charging system as claimed in claim 7, wherein the central control unit [1] limits charging level of the storage device [4] from one or more of the power sources [2] to a preset or user set value such that affected power sources [2] will not be able to charge the storage device [4] beyond the preset or user set limit but allowing other power sources [2] to continue to charge the storage device [4].

9. The electronic charging system as claimed in claim 8 charges the storage device [4] with all the power sources [2] or restricts the charging only from the solar power or restricts the charging from the power grid to a certain level of storage and then continue to charge only from other renewable sources of power.

10. The electronic charging system as claimed in claim 9 would feed the power to the load [6] from the next available power source [2] to get uninterrupted power, during under and over voltage conditions and thereby protecting associated devices and connected loads [6].