Event

Name: Arafat Hasnain

 

Committee:

Professor Alireza Khaligh (Chair)
Professor Xin Zan
Professor Sahil Shah
Professor Behtash Babadi

Professor Patrick McCluskey, Dean's Representative

Date/time: Monday, March 11, 2025 at 1pm 

Location: AVW 1146

Title: Investigation of Dual Active Bridge (DAB) Derived Power Dense Single-Stage Isolated Inverters

Abstract:

Power electronics converters are increasingly gaining importance in renewable energy applications. Single-phase inverter, in particular, which converts direct current (DC) to alternating current (AC) power or vice versa, is one of the most promising applications of power electronics in avenues such as solar photovoltaic (PV) and electrified transportation. Traditionally, the architecture of isolated single-phase inverters requires two discrete power conversion stages, i.e. an isolated DC-DC stage with a voltage boost cascaded with an additional high voltage DC-AC stage. This Ph.D. dissertation presents a study of isolated single-stage inverters based on dual active bridge (DAB) converters, which are typically used for DC-DC conversion. By studying the impact of topological modifications using direct matrix variations, this study extends the advantages of DAB converters for compact and high-efficiency inverter applications.

The dissertation focuses on modeling DAB derived topologies in the frequency domain specifically for DC-AC applications. This approach extends the conventional modeling of DAB converters for achieving low switching loss through zero-voltage switching and minimal conduction loss while meeting the AC power tracking requirement. Through the use of optimal phase-shift modulation parameters from non-linear constrained optimization in high-frequency models, the study introduces a three-dimensional lookup table-based methodology that allows the single-stage inverter to operate effectively at grid-line frequency. The integration of bidirectional voltage and current blocking switch configurations and planar magnetics are implemented for a compact hardware design. Furthermore, the single-stage isolated converter solution is extended for bidirectional power flow, enabling it to function as a low-voltage battery charger in micromobility applications. To further enhance the power density of single-phase inverters, a novel approach of integrating second-order power decoupling in a modified DAB inverter is introduced without the usage of additional active circuitry and large DC-link capacitors. The innovations from this work contribute to the wider adoption of single-stage DAB-based inverters in addressing key challenges within renewable energy systems.