Interview - Walk the talk
Senior Engineer, Hardware Design-Power Electronics,
Kislay graduated with a B.Tech in Electrical Engineering from IIT Gandhinagar.
A native of Birpur, Bihar, his interests range from adventure sports, music, literature to science. However, professionally he wants to be remembered as somebody who was part of a change and made a difference. He’s a senior electrical engineer at Ather and is our first employee. His role here is to design, develop and deploy the entire electrical power train for the next generation scooter being built by Ather.
PluginIndia.com spoke to Mr Kislay on the exciting new e-bike being developed and life at Ather energy.
Mr Kislay Pankaj
- Hi Kislay, Thanks for talking to PluginIndia.com. This will help the EV community get an idea of what it takes to work in the EV industry.
What made you join Ather Energy?
I was about to leave for a job offer in Delhi, when suddenly I got a mail from Swapnil, about wanting to talk to me regarding his company and the future of EV's. We sat at the Cafe Cofee Day outlet in Orion Mall for 2-3 hours and had a very fruitful talk.
I realized that the work Swapnil and Tarun was doing at Ather, was an opportunity to change an entire industry using technology (and science).
This is what I always wanted to do. I wanted to take the society forward by bringing in the understanding of science in a different way.
And of course, this gave me an opportunity to implement many of my EV related ideas. Hence, there was no second thoughts about it.
Fortunately, Swapnil was also impressed and he offered me to join Ather the very next day and I accepted. I am glad I did.
- What is your role in this project of developing the next generation e-bike?
Since I joined, my role has evolved a lot. But, in a crux, I am responsible for all the Power train and parts of it e.g. Charger, Motor and controller etc. The power team is working on an innovative Fast Charger these days. We are looking to develop a 2.4kW charger which can charge our Battery in almost 40 min to 80% SOC. This is an onboard charger, and hence size has to be very compact and other issues like losses and the cost has to be considered, which is a major challenge. More details about this charger can be found on Ather website.
We have plans to fully develop all modules in-house and hence the Motor and controller design is also on the plate in the future.
Apart from this I have the responsibility to expand the Power team, take care of overall Power train Integration and initiate vendor/supplier talks.
- We understand that Ather designs components inhouse, like the battery packs , integrated battery management system, the complete frame and drivetrain unit. Can you explain to our readers user how these components work together in an electric scooter?
each parts perform in sync with each other and are designed exactly as requirement, not under designed nor over designed. This approach is called vertical integration. For the scooter we are building, we have designed everything in-house except for the Motor, motor-controller and the cells.
Now, any electric scooter can be divided into 2 parts - Mechanical and Electrical Power Train. In our case we also have the Smart part. The basics of the mechanical system remains the same: Wheels, Gearbox (if any), Frame, Chasis, Body.
The Electrical Parts of any generic EV would have a Motor (as engine), a motor controller to drive the motor, the Battery pack (analogous to fuel tank), the Battery Management System (BMS) to control the Battery Pack of Lithium Ion cells and of course the charger.
The Battery is an energy source through which the Motor controller takes in the power to run the Motor at certain speeds and loads, depending upon throttle. Our Battery Pack is designed to operate for years at Indian conditions.
As Lithium ion cells can be dangerous if operated beyond safety limits, hence to have a control over it, there is the BMS which monitors and controls the charge, discharge, and the health of the battery pack. Our BMS also interacts with a central Vehicle Control Unit (VCU) for many system level operations.
And the charger does the job of refueling the Batteries. The more power the charger can run, the faster the charging time.
Our charger is also communicating to the VCU for control of charging rates , safety etc.
The concept of vertical Integration comes as in, say the charger team get inputs from the Battery and BMS team to make a charger which can pump the current as required by the battery , not more not less. Further, if there is a, say over current protection already in the BMS then I do not have to integrate it into my Charger thus saving complexity and cost.
Any design or features we do, in each module has to be discussed on a system level and implications on overall system as well as the other modules have to be discussed.
- Can you explain the differences between a charger and a controller and how do these parts help an EV? Also can you tell us about the specs of the chargers and controller, that you plan to use for the e-bike?
A charger and a controller have two very different purposes. As mentioned above, a charger is a Power Electronic Circuit which takes in the power from the grid (our home/office sockets) i.e. 230V AC 50Hz, converts it to the DC level at which the battery has to be charged. The control circuit inside the charger takes care of the CC-CV charging profile and various faults protection, say short circuit etc.
Whereas, a controller, more specifically a motor controller, is used to drive the motor. The controller is nothing but an inverter, which converts the DC from a battery to a specifically shaped AC. Most motor machines used these days, say BLDC, PMSM or Induction, requires 3 Phase AC current to run. The controller not only does this conversion but also controls the speed and torque that the motor can provide by controlling the Motor winding current Phase, magnitude and frequency.
Now the Charger function is analogous to refuelling the tank, and hence we always want to refuel as fast as we can and wherever we can. For this we need a high power on-board charger. That’s exactly what we are building at Ather. Our charger is a 2.4kW output charger capable of charging the battery pack at 1C charging rate, i.e. peak 40A of current. Hence you can charge the battery in less than an hour. We also have an additional slow charging mode for over-night charging etc. You don’t need any extra charging station for this, all you have to do is to plug-in the charger in a 5A/15A socket. Our Motor is powerful PM motor which takes in power from a nominal Battery Pack of Lithium Ion. Hence, the controller is doing this very job.
- How is the Ather charger different from other chargers?
First and foremost the kind of high power we are targeting is rare for an onboard charger. The reason is, that with current trends in the technology the charger module will be bulky and huge. The other thing is that it will dissipate a lot of heat. Even a 90% efficient charger will dissipate 240W of heat which is almost 3-4 times your Laptop charger total power o/p, for comparison. We are handling these important issues and targeting a charger which is 3-4 lesser volume than the normal trend. The challenge is to make all this happen is a price budget which is 3-4 times less than current trends for this power level.
Additionally, our charger also has a Power Factor Correction (PFC) stage. Most low power or poorly designed chargers don’t have a PFC stage, which in turn introduces noise into the grid. At a scale of million or more vehicles running (or charging), this noise or uncorrected Power has the capability of resulting into grid failures. Hence, we are putting a PFC and Filter stage which cleans the Power and hence, the grid sees a near resistive load. This ensures that even if we have millions of vehicles running the grid will not get affected due to this. Lastly, we of course have a charger which is interacting with the VCU, supplying vital stats and following instructions issues by the system
- This question is regarding DC quick charging. Many electric cars abroad and even Indian electric cars support DC quick charging where a dedicated charger delivers direct current (DC) power directly to the battery.
Also solar panels can send DC power directly to the battery pack of the vehicle for optimal charging.
Can the Ather battery pack support DC quick charging via Quick charge stations and Solar power systems?
Currently our chargers are designed to work for Indian Grid conditions i.e. 230V Ac, max 15A, 50Hz input. But some upgrades can be made in the future to take care of such needs. As far as the Battery Pack is concerned, it can of course sustain charging/ discharging of higher than the current rates but generally it will lead to lesser life of the pack. Again, going back to the vertical Integration approach, we have designed each and every part to work best and last longer, for the present needs and conditions, and hence deviations to that would be possible but with a compromise on life and reliability.
But we actually can use DC fast charging with very insignificant modifications.
- Tell us something about the work culture, and life @ Ather
While Ather is beyond that early start-up phase and things are falling in structure, but we still maintain the informal environment but hard work approach. Everyone is responsible for his own vertical and has complete ownership of that, both, in case of failure or success. We do not believe in too tight structures and hence there is freedom on the approach of your working styles. Some people like to work with music on while some like to work in the night. We respect each one’s style and only bother about the work we have, not the clothes we wear etc. (some still come to office in shorts, including me ☺ ). Any guy who loves his work and has passion in the work we do, is welcome and respected here. And of course we have, Pizza parties, team outings and birthday bashes (Yeah we still give B’day Bumps). In the end, Ather is a place for people who are passionate and enthusiastic about technology and do not want to bother about the rest of the world, but just build stuff.
- Thank you Kislay and good luck! We @ PluginIndia and the entire EV community are proud of the work you guys are doing.
We will support you and Ather in anyway we can.
Contact Ather Energy
3430, Shreyas,3rd Cross, 10th Main,
100 feet road, Indira Nagar,
Bengaluru, Karnataka – 560038
080 4190 0111
3430, Shreyas,3rd Cross, 10th Main,
100 feet road, Indira Nagar,
Bengaluru, Karnataka – 560038
080 4190 0111