an end to power cuts
Instead of AC (AC)
This is the standard for industrial and domestic power transmission and use around the world.
This is an innovation that uses solar energy and has been conceptualized and executed by Ashok Jhunjhunwala and Bhaskar Ramamurthi, two professors in the department, who are also IIT\'sM.
Some hostels in several other departments and institutes have done the same.
By linking the concept of decentralized solar energy
DC power supply based on grid
A group of researchers from IIT based on AC power
M, led by Jhunjhunwala and Ramamurthi, has come up with an innovative solution with the potential to provide 24 × 7 power supply to all households.
In a country about 60 years old, this may change the rules of the game
70 million households still have no access to electricity at all, and most of the rest are powered off every day, ranging from hours to 10 hours12 hours.
Those familiar with these two people who have worked for the past decade and a half know that they are basically experts in communication engineering, and they are not experts in power engineering at all, it seems unlikely that people will come up with such a revolutionary solution.
24x7 access seems like an incredible dream.
In the 1990 s, the two developed wireless local loops (WLL)
Through its corDECT solution, technology is provided for wider telecom access in developing countries, which is currently widely deployed in India and 15 other countries.
In fact, in IIT-
M, Jhunjhunwala leads the remote information processing and computer network group (TeNet)
This has nothing to do with solar or other power engineering solutions.
How did they get into this?
\"About two years ago,\" Jhunjhunwala said in a speech at the recent annual meeting of the Indian Academy of Sciences in Chennai, \"when there was a severe power outage in Chennai, it lasted two hours to 12 hours.
We have had enough for 14 hours.
Bhaskar and I feel there is something that has to be done about it.
So we started to do it.
A colleague said solar energy was the solution to the problem.
We started working on solar energy to see what we could do.
Solar power projects are being implemented under various state subsidies.
But we are surprised and shocked by how poor and inefficient the whole thing is.
No one applies any thought.
Everything comes from abroad;
Just plug it in and don\'t even need your mind.
Sometimes they work, sometimes they don\'t. ”The IIT-
M technology stems from the recognition that AC power supplies for basic domestic and commercial power needs, not DC power supplies, are a very inefficient way to use energy today.
Historically, communication has become the world\'s choice to use electricity because it allows the use of Transformers to increase or reduce voltage, which makes it possible to deliver large amounts of electricity over long distances through cheap infrastructure, and the energy loss is minimal due to heat heating.
As a result, most industrial and household appliances, such as fans, electric lights and water pumps, operate on AC power supplies.
However, with the emergence of power electronics technology, the basic disadvantages of DC no longer exist.
More importantly, all the electronic devices that people use today, such as LED/LCD (light-
TV, laptop, LED lights and phone/charger are all running at low levelvoltage DC.
But the home and office are still powered by air conditioning.
Therefore, in order to use them, the AC power supply is converted to a DC power supply using a converter, adapter or charger, which are usually built into the appliance.
But Jhunjhunwala says the conversion efficiency of these interfaces is poor, ranging from 25 to 50.
Solar power, especially through photovoltaic power generation (PV)
The production of DC power supply, the battery used to store solar energy also provides only DC power supply.
With more and more scattered solar power generation using rooftop solar panels, DC-
Household appliances such as refrigerators, air conditioners, washing machines and fans use brushless DC (BLDC)
Cars have begun to appear in the market.
However, the basic power supply network infrastructure is still communication. based.
So use DC-
Even with roof solar, connected homes become difficult because the load is ACbased.
The DC power supply of the solar panel must be converted to an AC power supply and synchronized with the power grid, and then converted to a DC power supply to run the connected load.
So even if we use a solar DC power supply, DC/AC and AC/DC conversion is necessary at different stages.
If we add a battery, normally this conversion is required again for the charging and discharging of the battery due to the large fluctuations in solar energy, since the battery only stores and provides DC.
According to Jhunjhunwala, each conversion will result in 10-
Therefore, when using solar energy with battery, the loss is about 30-45 per cent.
For example, Figure 1 illustrates communication in typical cases of solar utilization↔Low DC conversion efficiency↔This will result in a huge net loss of energy. Even in off-grid homes (OGH)
With rooftop solar, the problem remains, because electronic devices like LED lights, while laptops and mobile chargers run on DC, but they are designed to be plugged into AC sockets and other power supply interfaces for the grid.
Therefore, on the electronic device side, there will be further losses because this AC/DC conversion is required again.
\"It has to change, it has to go home --
\"If the energy consumption must be reduced, the load must move in the DC direction,\" Jhunjhunwala noted . \".
For example, while the 72-watt AC fan at the lowest speed will consume about 60 w of power, the equivalent 30 w BLDC fan consumes only 9 w of power.
Similarly, for a given light output, the LED light is twice as efficient as the CFLs.
The 2 m CFL consumes about 36 W and the equivalent LED light consumes about 15 W.
LED lights can be darkened as required, further reducing power consumption.
According to him, if DC becomes the norm and electrical appliances are produced in large quantities, the cost of the electrical appliance itself will not be much different. “Use of DC-powered energy-
\"Efficient equipment will reduce consumption by 50,\" he added . \".
Solar energy can be used directly to drive the DC load, or it can charge the battery where the DC power supply can drive the load.
This is basically what IIT has done internally.
M campus to demonstrate the direct use of solar direct current for the use of electric lights, fans and other electronic devices. The solar-
DC power supply system (Figure 2)
Developed by IIT-
M has a roof PV panel, supplemented with a battery, which is designed with a 48 V/3 v output to power the local DC grid running at that voltage.
The 48 v line inside the house/building powers DC equipment and appliances.
All air conditioning↔Therefore, the DC conversion is eliminated in the system.
Obviously, this can be replicated in OGHs in an easy way with scattered roof solar energy. Two Kolkata-
According to the University and secretary-general of the informal consultation of the delegation of scientists Parthasarathi Krishna: Witnesses to Banerjee, an independent study, has also been working along a similar route, use solar energy to drive household appliances and equipment at low voltage DC.
Their particular innovation is to replace batteries with solar energy.
A charged super capacitor, also known as an electrolytic or electric double-layer capacitor (EDLC)
, This is more effective and can be charged through more
Than the traditional battery discharge cycle.
They used a set of capacitors like this, and even designed and built models of Super Capacitors
Rail cars, bicycles and ferries.
However, due to the lack of resources for large-scale
Scale test or expand its scope of development.
\"As far as we are concerned, there is no chance to enjoy happiness --
Well-equipped research labs limit our manufacturing
In a recent paper describing their work, they wrote: \"End the prototype model. The IIT-
The M technology presenter actually went further.
In the case that the grid supply is available, the system can pass from the solar energy-Power battery.
The AC power supply of the power grid is converted to DC at 48 volts (
Use AC/DC converter)
Match the solar DC to the grid.
A subsystem called OGH.
Controller for IIT
Patented equipment that integrates 48 v DC power supply from PV panels, batteries and power grids (If any)
In such a way, the dependence on the battery is minimized.
Therefore, this technology can be used both in OGH cases and in nearOGH (
12-extended access limit for power outages14 hours a day)situations. The OGH-
The controller can also measure DC power consumption. The system (Figure 2)
There are two output lines: one main 48 v line and one emergency output line.
When the power grid has a long-term power outage and there is no significant solar output due to cloudy or rainy conditions, the main line is cut below a certain emission depth (DOD)of the battery.
Emergency lines can power several devices, such as lights and fans, and can be used for a long time even if the battery is low.
The deployment of OGH, such as solar panels of 125 watts and 200-500 watt-hours (Wh)
The battery in each house will include an LED tubeliight, an LED bulb, a BLDC fan, a remote control for operating the fan and tubeliight, a socket and a mobile charger. The solution (with 100 Wh)
Designed to run the BLDC fan, tubeliight and bulb at full speed for about 10 hours in a normal day, consuming only half of the battery (Ministry of Defense 50).
In the case of a decrease in the speed of the lamp and a decrease in the brightness, the power can last longer.
Emergency lines take over once the battery is low, which can last about 24 hours. The IIT-
M worked with several manufacturers to develop the solar lights, fans, remote controls, Chargers, sockets and solar panels needed for the OGH solution.
According to Jhunjhunwala, the specifications of these devices, including the operating standards for these 48 v DC devices (
It will be made public that any manufacturer is eligible to provide these products in the tender. Except IIT-
M campus, the technology has been piloted in Gudalur, Nilgiris (20 houses)
, Irakum Island in Neol, Andhra Pradesh, Dampada in Odisha, Hanskali in West Bengal, and a police station in Chennai and an Ayurvedic Hospital are
In fact, the OGH installation of Gudalur is based on the cluster home model.
In this case, an OGH system is deployed in a cluster of two to four households, and the main components driving the cluster are deployed in one of the households.
In this deployment, the biggest challenge is to install the system in the kuccha tribal family.
Another challenge is to teach the tribal people to use the remote control to operate the LED tubeliight.
There are about 0. 25 billion houses in India.
If you install 500 W (0. 5 kW)solar panel (
Measuring about 5 m)
In every family, with sunshine (
Exposed to the Sun)
About 1,500 hours a year, the total power generation is about 190 (0. 25 billion x 05 kW x 1,500)
GW per year is roughly the annual electricity consumption in China.
\"Scattered solar energy [with DC-
Drive equipment and devices
So it can have a huge impact.
\"It has the potential to free the grid from all domestic demand,\" said Jhunjhunwala . \".
If the above DC power supply system is widely used, the energy consumption of the whole country will be greatly reduced. The IIT-
M Group wants to expand it to a 100,000 discountgrid/near-off-
Power grid housing in different parts of the country.
In order to achieve this goal, government support is necessary and the Institute has provided this innovative solution to the ministry of electricity, the Ministry of new energy and renewable energy (MNRE)
Rural Electrified Corporation (REC).
Of course, it will cost to implement, operate and maintain these DC systems.
Rough estimates based on IIT
M, in the pilot phase (100,000 homes)
Implemented, the cost per household is about Rs. 20,000-30,000 (including five-
Depending on the terrain, type of house and density.
For 100,000 units, the total cost is about Rs. 300 crore.
They hope that this will be achieved through a mix of governments (MNRE)
Funding for subsidies, state and other government agencies, private donors and corporate social responsibility obtained through the Institute (CSR)schemes. Although IIT-M’s OGH/near-
The OGH system provides uninterrupted DC (UDC)
By providing low power
In the presence of power grid connections, horizontal battery backup does not really solve the basic problem that the two professors are working to solve, that is, eliminate power outages.
\"This also does not create a pull factor for solar energy,\" Jhunjhunwala added . \".
According to him, a former Minister of Power pointed out that only half of what they did.
\"We need more innovation to address power outages while providing the necessary technological push for decentralized solar and energy --
High efficiency DC appliances.
The problem with IIT is --
What my team is asking is, not a simple back-
Solar cells on the consumer side can light up a bulb or fan at most, and what can people do on the grid power supply or sub-power supplystation end?
Idea of IIT-
M group then proposed that if implemented on a large scale, it would be possible to get rid of the power outage and have the possibility to change the rules of the game in the country\'s power scene.
Of course, in addition to technological push, policy push is needed to achieve this goal.
It is hoped that appropriate policy support will also be provided so that the idea can be implemented nationwide.
What is this breakthrough idea?
Today\'s grid supply operates in \"either\"/\"or\" mode: The grid is designed to carry all the power (
Normal 100)or zero power (load-
Fall off/power cut, 0%). The IIT-
M technology includes the introduction of a new low
AC power cord (
Ten per cent)
And provide a minimum number of DC power to all 24 × 7 households on the existing power network at 48 v.
Obviously there is a need to make some adjustments to the substation, which, according to Jhunjhunwala, will make minimal modifications to the grid without costing a lot.
This is the so-called \"brown\"out” mode.
In the substation, there will be two lines that will appear from the distribution transformer, usually the 230 V line and the 90 V line.
Only the latter will remain open.
On the consumer side, the 90 v power cord is converted to a 48 v DC line via an AC/DC converter, which will be similar to earlier OGH cases.
When the main 230 v ac line is cut off in this mode, the low power 48 v dc line is always \"on (Figure 3).
It is no stranger to having two power grid lines, as most families have separate lines of 5 and 15 amps.
This will be similar. This low-
According to the team, limited levels of power are small enough to be readily available even in the most severe power crisis.
What if consumers get any amount of power from this line, causing the grid to crash?
Jhunjhunwala pointed out that the main line should be cut automatically and instantly in one millisecond and let the other line open.
How to design this instantaneous cutting problem
Before Jhunjhunwala and Ramamurthi came up with innovative solutions, off had been bothering for months.
When there is a power outage, the voltage at the end of the substation will drop rapidly.
So when the voltage drops 2 times from 230 V. 5 (90V)
The system should signal Brown.
Cut off the main line.
Through GPRS (
General Packet Radio Service)
In the mobile network system, the substation will immediately signal to the home cluster. out.
The main line was cut off.
Turn off and retain only the 10-minute capacity line of the power supply DC, the power you can extract from it is limited by the design.
\"Voltage drop to do the normal idea --to-brown-
\"For us, the signal is eureka moment,\" said Jhunjhunwala . \".
One might also ask if a family\'s 10 cents of electricity is enough to work.
It\'s actually Brown.
The Out situation is very similar to the OGH situation, except that the DC power supply comes from the grid itself, not from solar panels or batteries.
Because people use high energy.
Like OGH, efficient DC devices can run a large number of household appliances.
According to Jhunjhunwala, 48 UDC lines provide 100 watts of power per home, which can support three lights and two fans (
Or a fan and an led TV)
And a phone charger.
If anyone wants more, solar PV can be added and battery support can be provided if needed.
The 500 watt solar PV can support five fans, three lights, two TVs, multiple mobile chargers and laptop chargers.
Uninterrupted DC power supply module for measuring DC consumption (UDPM)
This is part of the installation, use.
It is achieved through a wireless system based on Bluetooth technology.
Consumer data is transmitted via Bluetooth to an android phone connected to the watch box. This brown-
Out technology has been extensively tested and tested in IIT
M, and successfully verified in Madhuranthakam near Chennai on December 2014.
Up to 281 houses are covered, and even though the rest of the area has extended power outages, the nearby cluster is still on.
According to Jhunjhunwala, the neighborhood is also interested in this and wants to replicate the model there. Brown-
Technical installation is also underway in Telangana (Moinabad)Kerala (
Thiruvanathapuram)and Odisha. While large-
There may still be some policy and regulatory issues due to government investment involved, via OGH/near-
OGH technology, it does have the potential to reduce power supply
There is a large demand gap, and if government agencies provide the necessary support, including the normalization of DC appliances and the efficiency rating of the energy efficiency bureau, the demand gap may widen (BEE)
Even financial incentives allow manufacturers to enter the production of DC appliances on a large scale.