Tirthasarathi Lodh Associate Scientist at ABB GISPL 

SUMMARY

 

I received the B.Tech. Degree in Electrical Engineering from Jadavpur University, India in 2014 and M. Tech. Degree from the Dept. of Electrical Engineering, IIT Bombay, India in 2017. The areas of study in which I received the M. Tech. Degree is single phase grid-connected and standalone solar PV microinverters and active power decoupling schemes for single-phase AC systems. I am currently Associate Research and Development Engineer at Asea Brown Boveri (ABB) Global Industries and Services Private Limited. I worked on the design of the cell electronics for the high-power devices used by ABB for the HVDC and FACTS related projects at ABB. I also worked on semiconductor loss calculation and thermal modeling for the power converter topologies for the SEMIS Tool maintained by ABB Semiconductor group.

 

RESEARCH INTERESTS

 

• Grid-connected and Standalone Solar PV Systems

• High-gain and High-Efficiency DC-DC Converters

• MMC and its Dynamic Performance Study

 

ACADEMIC STATEMENT

 

Electricity is one of the cornerstones on which modern society is built. In India, significant developments have been made in the last few decades towards making the effects of these new technologies easily accessible to the people, especially in rural India. Although there has been significant support towards research and development in the field of solar PV and other renewable energy sources from the government of India, the deployment of these technologies faces several roadblocks, poor compatibility of India's grid condition and lack of awareness about standards and regulations being only some of them. Given the ubiquitous need of introducing these new resources in rural India, I consider it my duty as a researcher in the field of Power Electronics to develop technologies that can be launched with ease in the market. 

The undergraduate courses such as Power Electronics Design, Electrical Drives offered by Jadavpur University (JU), and the postgraduate courses such as Applications of Power Electronics in Power Systems, and Power Electronics for Renewable Energy sources provided by Indian Institute of Technology Bombay (IITB) instilled in me a keen interest for this field. The exposure to the cutting-edge research being conducted on Power Electronics by the renowned professors of JU and IITB propelled me to work on several course projects, whose detailed list is included in my website (Link). During the course of these projects, I performed converter and control simulations using Matlab/Simulink, designed printed circuit boards using OrCAD, performed thermal modelling and semiconductor loss calculation using PLECS, performed component level simulations using PSpice and LTSpice, performed system level simulations using PSCAD, implemented the firmware using Code Composer Studio programming for TMS320F28335 DSP, performed real-time simulations using dSPACE. All these acquired software skills helped me immensely in the implementation of my research ideas related to the Power Electronics during my M. Tech. Project. Some of these projects required me to work in groups, which helped me develop team spirit and leadership skills. My sound conceptual background and dedication towards my goal enabled me to grasp the advanced concepts and software skills which eventually helped me to earn a CPI of 9.7/10.0 and secure 1st position among the 15 postgraduate students of Power Electronics and Power Systems (PEPS), IITB during my M. Tech.

My strong research aptitude, analytical and technical skills guided me to form of novel ideas and validate them successfully. Having grasped the fundamentals in the field of Power Electronics and Renewable energy sources, I chose to work on single phase standalone and grid-connected PV microinverter systems for my master’s thesis. I developed and successfully tested two novel topologies of reliable, compact, low-cost and efficient solar PV microinverter in the power range of 300W. One of the topologies addressed the grid-connected application for urban areas, and the other one addressed the standalone use with battery backup and remote monitoring for rural areas. I proposed Active Power Decoupling (APD) schemes for improving the reliability and overall lifespan of the `inverter. The proposed APD schemes resulted in very low voltage ripple across PV, high MPPT efficiency and low grid current total harmonic distortion (THD) along with the recovery of the transformer leakage energy. I also proposed and validated a control method for improving the efficiency of the interleaved flyback converter based microinverter. The control method judiciously chooses an appropriate combination of DCM/BCM and 1-converter/2-converter operation based upon the instantaneous power to enhance the operating efficiency. In addition to these, I proposed highly-efficient and compact topologies of transformerless microinverter having a single high-frequency switch, which eliminates the earth leakage current due to the parasitic capacitance between the PV and ground. I proposed and validated coupled inductor based highly efficient high-gain converter topologies with excellent leakage energy recovery and microinverters derived from them to connect low-voltage DC sources like PV, battery, ultra-capacitor, etc. to the utility grid. Given my strong educational and research background, I hope to contribute significantly to the field of Power Electronics.

My academic excellence and persistent hard work resulted in the selection of my paper, ‘Novel Control Scheme for an Interleaved Flyback Converter Based Solar PV Microinverter to Achieve High Efficiency’ for publication in the reputed International Journal called IEEE Transactions on Industry Applications. Another paper, ‘Parallel-Input Series-Output Interleaved Flyback Solar PV Module Integrated Inverter’ is under revision with another reputed International Journal called IET Power Electronics. Apart from these, the complete list of my 22 conference papers, published in renowned IEEE conferences like PEDES, ICRERA, ICPEICES, PIICON, etc. has been included in my website (Link). I have always attempted to make full use of the resources available to me in furthering my objectives. Currently, at ABB GISPL, I am working in the HVDC business group of the Power Grid division. This industrial experience will supplement my research, and provide me with the knowledge of economics necessary to effectively bring new technologies to market.

 

PERSONAL STATEMENT

 

I grew up in Tripura, which is a tiny northeastern state of India, rich in scenic beauty and cultural diversity. During my childhood, I studied in a Senior Basic School of a remote village in Tripura named Melaghar. My father had a transferable job. After the transfer of my father to the capital town of Tripura named Agartala, I had to appear for stringent competitive admission tests of class six. I performed excellently in those tests to get admission in Netaji Subhash Vidyaniketan, one of the best schools of Tripura. Due to the dedication towards my goal and the ability to adapt quickly in the challenging situations, I soon positioned myself among the toppers of my class. Due to the shortage of infrastructure and poor connectivity, no heavy industry could ever develop in my economically backward hilly state, whose economy relies upon the sectors like agriculture, horticulture, fishery, animal husbandry, tea, coffee, rubber, and other small-scale industries. The opportunity for higher education and a good job is insufficient in Tripura. Having a high aspiration towards life, I decided to appear for highly competitive national level examinations even though I was well aware of the absence of high-quality coaching centers in Tripura. As a result of my persistent efforts, I performed excellently to get admission in the renowned Electrical Engineering Department of Jadavpur University (JU) situated at one of the metropolitan cities of India named Kolkata. The overall educational expenses and the cost of living in JU are the cheapest, least among the renowned institutes of higher education in India. During the tenure at JU, I came up with new challenges and came in contact with the distinguished faculty members. The first challenge was to adapt to the sudden change of the teaching language from Bengali to English, which I overcame soon enough by spending extra efforts in a daily basis to make me well acquainted with the usage of English language. Here, due to my deep involvement in the studies and the experiments, I got so fascinated by the marvels of the Electrical engineering that I wanted to broaden my knowledge base by pursuing higher education. Driven by my strong passion towards electrical engineering and the urge to explore the best in the field, I joined Indian Institute of Technology Bombay (IITB), the best institute for engineering in India, which is located in the extreme west of India far away from my native village.

During my tenure at IITB, I connected with many people from different parts of India as well as the world so nicely that I have established a healthy relationship with them. India is a vastly diverse country with many linguistic, cultural and social differences. I have visited many parts of India, imbibed good customs and virtues from every culture. I could easily adjust to the local environment and mingle with the people. Due to my active involvement over the years, I have created deep bonding with the Tata Center for Technology and Design (TCTD) of Massachusetts Institute of Technology (MIT), Boston. I attended the workshops on Innovation and Entrepreneurship by MIT TCTD faculty members. I accompanied the MIT Tata Fellows to their field trips during their visit to IITB as part of their India orientation and market study for projects. I extended warm hospitality that resulted in friendly relation with many of the students from the USA belonging to the different cultural background. I had been fortunate enough to learn about the exciting projects run by the MIT TCTD through the interactive sessions, seminars and laboratory visits conducted by the distinguished researchers and faculty members at MIT during the IITB-MIT collaborative study tour held in the first week of May 2015. Through the project called Design and Fabrication of Power Electronic Controllers for Certain Home Appliance Motors, I have worked in collaboration with the research group of Prof. James L. Kirtley Jr. My association with the people from many parts of my country and around the world developed in me an urge to shape my personality in such a way that I would strive to contribute to the process of development for the mankind by innovations.

The people who face racial/gender inequalities and other financially/socially backward sections of the population, the bottom of the pyramid (BOP), are vital to the sustainable growth of the world. In a stable state of mind when the financial and social security is ensured, people tend to pursue higher education. I believe that the government has to play a significant role to improve the life condition of these people. The government has to allocate funds to be spent in the form of direct donations or subsidies to the people of BOP. The government should also take extreme care by imposing stringent rules and regulations to make sure that the total fund allocated for the BOP reaches them intact. The fund apportioned for the BOP should not be illegally taken up by any third party influenced by the widespread corruption prevalent in the country. The drawback of direct donations and subsidies is that they tend to make people lazy and create a sense of dependency upon the government. Hence, to accomplish the mighty objective of bringing the BOP people out of the poverty line and making them self-sufficient, the government should focus on growing the capability of the BOP people by providing free or low-cost training on different skill sets, which will enable them to be self-sufficient. This approach will not only sustainably improve the financial and social status of the BOP but also contribute significantly towards the overall economic growth of the country. The quality of education in rural schools is another facet which needs to be improved considerably. The education quality can be enhanced by conducting periodic reviews, teacher training programs, video lectures and interactive sessions involving accomplished faculty members from distant locations, either in person or over the internet. BOP being the significant chunk of the population of the third world countries; government spending might not be sufficient enough to tackle the complex social issues faced by them. The government should focus on spreading awareness about the enormous hidden potential and the opportunities in the BOP market as an effort to address the issue of lack of fund. This fact can attract substantial private investment in the area. The objective of engaging private funding can be achieved by encouraging research projects directly related to the BOP market in the institutes of higher education and by easing the policies for different industrial and entrepreneurial initiatives in the sector. The large customer base of the BOP market allows us to achieve high overall profit even with a low-profit-margin per product. It is equally important to educate the entrepreneurs, innovators, and investors about the challenges associated with the BOP markets and to train them about the design of new product and business models required to tackle those challenges. The BOP products are needed to be environment-friendly and at the same time meet the stringent requirements of high-reliability, low cost, and ease of use.

During the course named Technology Design and End to End Innovation, I have been trained extensively through the various case studies of the successful products and the business models for the BOP; such as Arvind Eye Care, Jaipur Foot, Portable ECG Machine by GE, Chotukul, etc. I attended the interactive sessions with distinguished personalities who have created an enormous impact through their frugal and disruptive innovations in the fields like healthcare, energy, education, and housing. Having a strong research background, knowledge of the efficient project execution methods like design thinking (DT) and lean product development(LPD), I firmly believe that I can contribute significantly to the cutting edge research required for the BOP people. My aim is to bridge the gap between the BOP and the bright minds of the country. I plan to accomplish this goal through the impactful collaborative research projects with the industry and social service organizations. My strong urge for the involvement with the various sections of the community propelled me to go for field trips to the remote parts of our country and empathize with the challenges faced by the people. During the winter of 2015, I went for a field visit to the organization called NIRMAN situated in a remote village of Maharashtra, India. This field trip helped me in understanding the challenges related to health care faced by the local inhabitants due to their stay at remote locations. During these trips, I realized how the highly dedicated, and self-motivated individuals associated with NIRMAN were able to educate and provide world-class healthcare without disturbing the local practices. I eagerly participated in sessions like daily prayers, cleaning up of the premise and plantation of trees. I even went to stay in the houses of the villagers to understand their needs and everyday challenges. I presented a list of issues and pitched tentative ideas to address them. Among them, the concept related to an efficient cookstove to reduce the firewood consumption was highly appreciated. During my tenure at TCTD IITB, I, along with the other TATA Fellows and the project engineers, used to conduct the renowned national event called KALPANA to encourage innovation among the student population of India. The event provided an ideal platform for most innovators, showcasing their talent in prototype making and poster making. This event used to receive thousands of applications from across the country. In the TCTD lab, I developed an Assistive Mobility Device for Visually Impaired People. I did background research and interviewed the end-users and stakeholders to identify the challenges faced by the visually impaired. Specifically, I visited Smt. Kumudben Dwarkadas Vora Industrial Home for Blind Women and Xavier's Resource Center for the Visually Challenged located at Mumbai. I analyzed the existing alternatives available in the market and found out the drawbacks in them. Based on the insights obtained from the user studies, I built and successfully tested a working prototype of an assistive mobility device using my knowledge of electronics and programming skills. The device uses ultrasound technology for the detection of the obstacle distance and a vibration motor - based tactile interface system that generates different vibration patterns as a function of obstacle distance to alert the user. The device significantly helps in the smooth navigation of the visually challenged people.

My parents instilled in me the ethical values like devotional working, patience, perseverance, honesty and loyalty. The stringent time constraint faced due to the necessity of completing many courses at a time prompts to go through the subject matter superficially only to fulfill the exam requirements. But, I could strongly feel that any such deflecting ideas would not help in true knowledge creation, and I would not be able to reach my long-term goal. In the face of challenging situations, I would rather strive to increase my potential and engage with higher devotion to grasp the depth of the problem. This approach yielded a successful outcome in my research projects. These successes have given me immense pleasure and served as a huge confidence booster. I now gladly look forward to engaging myself to my passion for scientific research. I firmly believe that genuinely knowledgeable personalities only can bring substantial changes in society and are always highly regarded by the people in the community. Apart from the timely execution of the part of the work assigned to me, I used to arrange regular meetings among the team members of course projects (Link) during my M. Tech. These meetings helped us to reach the root cause of a problem through collective brainstorming and plan the next course of action for every individual. During many of the brainstorming sessions, I had been able to give higher value opinions, which were greatly appreciated and readily accepted by my colleagues. I used to spend a significant portion of the day in the laboratories through which I created strong bonding and good rapport with the senior researchers. Whenever any of the group members got stuck with some critical issues, I could easily approach the senior researchers and return to my teammates with the expert suggestions, which played a vital role towards the smooth progress of the projects. Due to my goal-oriented mentality, I used to encourage my colleagues to have patience and positive thinking towards the targeted outcome even in the face of challenges. I improved the art of reaching common ground in a peaceful manner respecting the viewpoint of every individual. Apart from my research and studies, I used to engage in voluntary activities like sharing the experiences and study materials to the juniors to help them for their job interviews. I also explained the various lab facilities available at our department to the new joiners and the visiting researchers. I experienced critical reviews in my research work and realized the value addition through the process. Also, during my work tenure at ABB, I completed the training courses on Electrostatic Discharge, Electrical Safety, Fire Safety, Cardiac Pulmonary Resuscitation to make me capable enough for playing a vital role in mitigating unwanted hazardous situations in the work environment. I have taken the courses on Integrity, Anti-bribery, Business Ethics, Plagiarism conducted by ABB. The training programs have improved my insights on professional ethics.

It is an alarming fact that even in the face of the twenty-first century; many people living in remote villages and the slums of the cities don’t have access to electricity. On the other hand, conventional fossil fuel energy sources, which cause tremendous environmental pollution, are almost getting extinguished. Hence, renewable energy sources are inevitably becoming the only hope for the future. But, due to their high cost, complex source characteristics and uncertainties associated with the natural phenomenon, it is incredibly challenging to extract power from them smoothly and efficiently. Advanced power electronic circuits with advanced control methods can leverage the enormous potential associated with renewable energy sources. As a step toward this direction, during my master’s thesis, I proposed ideas to reduce the cost, improve the efficiency and reliability of the standalone solar PV microinverters, which can supply power to the remote villages where the utility grid is still not available. Having an in-depth understanding of the various socio-economic challenges of the developing nations and a holistic educational and research background supported by the industrial experience, I firmly believe that I shall be able to contribute significantly in the field of Power Electronics and bring impactful changes in the society through cutting-edge research.

 

Acknowledgments ​

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I am truly grateful to the TCTD IIT Bombay, a unique place with unique facilities where I enjoyed research in an interdisciplinary environment and which gave a fair amount of exposure of the end to end innovation process. During the span of last two years, I have grown a deep bonding with the truly enthusiastic people associated with TATA center. It’s like a second home to me where I feel like being with my family. Attending the workshops organized by TCTD helped me to explore various technologies beyond my own research field. Visiting ‘Gadchiroli’, helped me to empathize with the needs of the people in the bottom of the pyramid to some extent. The visit to MIT, where I came to know about some of the research methodologies and work culture of the world’s most prestigious institute of engineering and technology, was something like a dream comes true.  TCTD IIT Bombay has provided me an opportunity to study in one of the best institutes of the country in the field of engineering and technology. I have been fortunate enough to work with Prof. Vivek Agarwal (Fellow IEEE), a distinguished faculty in the field of power electronics. Under the esteemed guidance and suggestions of my truly motivational sir and extremely knowledgeable and helpful colleagues of Applied Power Electronics Laboratory, Electrical Engineering Department of Indian Institute of Technology Bombay, I developed some skills for the research in Power Electronics field and have been able to publish my research work in some national and internationally reputed conferences. The colleagues of APEL were always available with their valuable suggestions in all sorts of purchase, design, fabrication, software hardware and conceptual issues. I want to acknowledge the suggestions of Nataraj Pragallapati, with whom I have been working in collaboration on several research ideas and the immense help provided by Pratik Patil to establish the communication link for the Microinverter. My best wishes for Ramjith Ramachandran, who has been patient enough to understand the relevant concepts and experiments of the project and is going to take my work forward. I am really grateful to TCTD and APEL, who has been a constant source of encouragement and provided me with various opportunities to enrich the possibilities of my good academic as well as the professional career in future.