Anandarup Das
Research AREAS
Welcome to the research profile of Anandarup Das. Here you will more information about the recent research work that we are doing here in IIT Delhi.
multilevel converter
Modular converters for example MMC and CHB have become very popular in recent years in high power applications where large number of identical small rated building blocks are used. Typical applications include grid integration of large scale PV system, battery energy support, medium voltage fast charging of EV and high power motor drives. We have been developing new modular converter topologies, modelling, control and PWM switching strategies, and building of prototype to demonstrate fundamental and advanced feautures of these converters.
We have designed and tested several modular converters at different voltage and power ratings using commercially made submodules and our own in-house PCB based submodules using IPM.
MMC/CHB for PV/battery storage
MMC and CHB are inherently modular. With PV or BESS, the arm, leg and 3-phase powers will be mismatched. We have proposed new zero sequence voltage injection techniques to counter this issue.
Modular converters for MVDC/HVDC integration
Medium voltage direct current (MVDC)-based grids have become appealing in recent years due to the high penetrations of distributed energy resources and energy storage. It can help in independent control of active and reactive power flows, decoupling grids with different frequencies, higher conversion efficiency, etc.
We have obtained several fault tolerant MVDC configurations using modular cells giving excellent performance during both AC and DC side faults.
high frequency
power electronics
High frequency power electronics can help in reducing the size of passive components and heat sink. With Silicon Carbide and GaN based devices, switching frequency of the order of MHz are not uncommon.
We have been working on SiC based Dual Active Bridge Converter (DAB) and folder/unfolder circuits where we are getting efficiency in excess of 98% for lab prototypes. These are used in Electric vehicle power-train or grid connected applications. A good amount of research and development is undergoing in our group in building gate drivers, heat sinks, in built PCB based sensors for SiC based converters along with new PCB designs for the converter.
3-phase folder-unfolder
One interesting development based on SiC devices is the folder/unfolder circuit. It creates a sinusoidal output from an inverter (no PWM) without using any output filter. The DC link capacitor is also substantially small. It can have many potential benefits like zero common mode voltage and no wave reflections at motor terminals etc. Experimental results show negligible voltage reflections even with a 100m cable.
single phase folder-unfolder
Three phase unfolder concept can be extended to single phase applications. Grid connected PV systems with single phase unfolder can drastically reduce the leakage current of the PV systems.
Dual active bridge converter
Dual active bridge converters (DAB) are considered one of the important isolated DC-DC converters of the future. We have experimentally tested resonant DAB at 3 kW power level for EV charging applications touching a peak efficiency of 98.5%.
We are in the process of increasing the power and voltage range of DAB in our labs.
Power electronics dominated GRID
A lot of development is now taking place in developing power grids dominated by power converters. Use of virtual inertia or integration of battery storage system opens up new challenges for control of converters during various grid events. We are presently working on finding suitable solutions for providing virtual inertia to the grid using modular high power converters. It has been observed that different modular converters contain substantial stored energy in the capacitors. This can be used as and when necessary by the grid whether the converter works in grid forming mode or grid following mode. A high powr multilevel converter can seamlessly work in grid forming mode.
TRaction power converters
For past few years we are involved in projects related to high speed railway traction. We have an ongoing project with National High Speed Railway Corporation in which we are developing computer simulation software for traction load flow studies, harmonic analysis, short circuit and contingency analysis etc. The project also offers new direction of development for traction power converters, harmonic mitigation techniques and fail-safe and reliable operation for high speed railway system. There is a high scope of development in India on this subject.