𝐁𝐢𝐝𝐢𝐫𝐞𝐜𝐭𝐢𝐨𝐧𝐚𝐥 𝐓𝐡𝐫𝐞𝐞-𝐩𝐡𝐚𝐬𝐞 𝐂𝐮𝐫𝐫𝐞𝐧𝐭 𝐒𝐨𝐮𝐫𝐜𝐞 𝐂𝐨𝐧𝐯𝐞𝐫𝐭𝐞𝐫 𝐛𝐚𝐬𝐞𝐝 𝐁𝐮𝐜𝐤-𝐛𝐨𝐨𝐬𝐭 𝐀𝐂/𝐃𝐂 𝐒𝐲𝐬𝐭𝐞𝐦 𝐮𝐬𝐢𝐧𝐠 𝐁𝐢𝐝𝐢𝐫𝐞𝐜𝐭𝐢𝐨𝐧𝐚𝐥 𝐒𝐰𝐢𝐭𝐜𝐡𝐞𝐬

• Design and hardware implementation of a 10 kW buck-boost AC/DC system, consisting of an interleaved buck converter and bidirectional switches based current-source converter, for 400 − 800 V DC to 480 Vrms applications.
• Evaluated the impact of different commutation and modulation schemes on the converter performance.
• For the hardware prototype at 480 Vrms, 10 kW output with a 400-800 V DC input and 100 kHz switching frequency, system efficiency and AC currents THD varied between 98.85 % to 98.14 % and 3.8 % to 1.3 %, respectively.
  
  

𝐓𝐡𝐫𝐞𝐞-𝐩𝐡𝐚𝐬𝐞 𝐚𝐧𝐝 𝐒𝐢𝐧𝐠𝐥𝐞-𝐩𝐡𝐚𝐬𝐞 𝐈𝐬𝐨𝐥𝐚𝐭𝐞𝐝 𝐒𝐢𝐧𝐠𝐥𝐞-𝐬𝐭𝐚𝐠𝐞 𝐀𝐂/𝐃𝐂 𝐂𝐨𝐧𝐯𝐞𝐫𝐭𝐞𝐫𝐬 𝐮𝐬𝐢𝐧𝐠 𝐌𝐨𝐧𝐨𝐥𝐢𝐭𝐡𝐢𝐜 𝐁𝐢𝐝𝐢𝐫𝐞𝐜𝐭𝐢𝐨𝐧𝐚𝐥 𝐒𝐰𝐢𝐭𝐜𝐡𝐞𝐬

• Design and hardware implementation of 2.3 kW single-phase and 10 kW three-phase, single-stage, bidirectional, isolated AC/DC converters using in-house designed and packaged monolithic SiC Bidirectional FET (BiDFET).
• Hardware design includes power stage, FPGA and DSP based control, gate drive, overvoltage and overcurrent protections, high-frequency voltage and current sensing circuits, differential-mode EMI filter, system-level protections, and thermal design.
• Single-phase converter achieved 95.3% efficiency, 4.7% current THD at 400 V DC input and 277 Vrms output at 100% load.
• Three-phase converter achieved 98.1% efficiency, 3.5% current THD at 800 V DC input and 480 Vrms output at 100% load.
  
  

𝐒𝐭𝐚𝐭𝐢𝐜 𝐚𝐧𝐝 𝐃𝐲𝐧𝐚𝐦𝐢𝐜 𝐂𝐡𝐚𝐫𝐚𝐜𝐭𝐞𝐫𝐢𝐳𝐚𝐭𝐢𝐨𝐧 𝐨𝐟 𝐌𝐨𝐧𝐨𝐥𝐢𝐭𝐡𝐢𝐜 𝐒𝐢𝐂 𝐚𝐧𝐝 𝐆𝐚𝐍 𝐁𝐢𝐝𝐢𝐫𝐞𝐜𝐭𝐢𝐨𝐧𝐚𝐥 𝐒𝐰𝐢𝐭𝐜𝐡𝐞𝐬

• Die-level and package/module-level static characterization of switches, including V-I characteristics, transconductance, gate leakage, gate voltage threshold, drain-source leakage, and parasitic capacitances using curve tracer.
• Commutation cell design, including commutation loop optimization, gate driver design (gate resistance selection optimized for tradeoffs between switching losses, overvoltage, dv/dt induced false turn-on, negative gate voltage limit with/without miller clamp or other clamping mechanisms and other system-level considerations), short-circuit fault protection,and open-circuit fault protection.
• Dynamic characterization to determine switching losses; transition times; dead-time and overlap-time requirement; and protection circuitry testing.
• Design and hardware validation of the on-chip temperature sensor in SiC BiDFETs.
  
  

𝐇𝐢𝐠𝐡-𝐏𝐨𝐰𝐞𝐫 𝐒𝐢𝐧𝐠𝐥𝐞-𝐏𝐡𝐚𝐬𝐞 𝐏𝐅𝐂 C𝐨𝐧𝐯𝐞𝐫𝐭𝐞𝐫

• Performance evaluation of Si, SiC and GaN FETs based high-power (>5kW), single-phase power factor correction (PFC) converters including conventional and bridge-less topologies.
• Design, hardware implementation, debugging and testing of high-power, wide-input, grid-connected, low-cost, high-efficiency (80 PLUS Platinum standard), low input current THD (based on IEEE 519 and FCC/CISPR recommendations), single-phase PFC converter.
• Design included power-stage, analog control, inrush current limiting circuit, EMI filter, protection circuitry, FETs gate-drive, sensor circuits, auxiliary power supply, thermal design, component selection, schematic capture, and PCB layout.
• Design validation testing included electrical performance testing in the whole input voltage and load range, and thermal performance testing in the whole input voltage range at full load.
• Hardware design met all the electrical performance indices in the whole operating range per relevant efficiency, THD and PF standards.
• Semiconductor devices’ junction temperatures were estimated by sensing the baseplate temperatures. Estimated worst-case junction temperatures for devices were 30-50C below their rated values.

• Analysis and testing of 2.5 kW Phase-Shifted Full-Bridge converter (PSFB) with Full-Wave Rectifier as output stage.
• Design, hardware implementation, debugging and testing of “Buck converter based Active Clamp” to reduce voltage stress and ringing across the secondary-side switches of PSFB converter.

• Worked towards the development and deployment of extra low voltage DC systems and microgrids in under-electrified rural areas of India.
• Designed a multiple-input, multiple-output converter to power the household essentials through intelligent use of available power from electric grid, off-grid solar PV system, and electric batteries.
• With solar PV and battery (which are inherently DC) as sources, the direct use of DC power would result in the reduction of power converter stages (AC to DC and DC to AC conversions) for feeding modern DC compatible devices (like LED lights, LED television, fans, water purifiers, laptops, mobiles etc, which have an AC to DC converter as their input stage), leading to increased reliability and better efficiency.

• Worked on world’s first retrofittable cooling backup product, for milk cooling and cold storage.
• Designed BLDC motor controller (24V, 48V, and 310V), AC/DC converters, DC/DC converters, PFC Boost converter-based power supply, gate drivers, and motor electromagnetic configuration (pole/slot ratio, stator size, rotor size, winding pattern and number of turns, and wire gauge size) for different applications: refrigerant pump, condenser fan, and ceiling fan.
• Integrated the cold storage including compressor unit, evaporator and thermal battery to off-grid solar PV system.
• Hired and managed the technical staff, consultants, and vendors.

• Worked under the guidance of Dr. Rachna Garg on a hardware research project ‘200W solar-powered battery-backed DC nanogrid using NI myRIO’.
• Developed MATLAB simulations of hardware topology and LabVIEW program of MPPT algorithm.
• Designed magnetic components like transformer and inductor.