Research Focus: Power Converter Topologies
My research centers on the design of power converter topologies, spanning DC–DC, DC–AC, and AC–DC conversion, with a particular focus on high step-up and high-gain converters for renewable energy sources and electric vehicle applications. Across my published work, this has developed into a few connected threads.
High-gain topologies for low-voltage sources
A recurring problem in renewable energy systems is that sources like PV panels and fuel cells produce a low DC voltage that needs a substantial boost before it can be used, and conventional boost converters simply cannot reach that gain efficiently at a reasonable duty cycle. Much of my early and ongoing work addresses this directly, building high step-up converters around coupled inductors, voltage multiplier cells, switched capacitors, and center-tapped windings, techniques that let a converter reach an ultra-high voltage gain without resorting to an extreme duty cycle or a large parts count.
Rather than treating each converter as a one-off design, several of these projects introduced entire families of related topologies built around a shared core idea (for example, a family of center-tapped-inductor converters, or interleaved converters using multi-winding coupled inductors), so that a designer can choose the variant that best matches their gain, cost, and complexity requirements.
Soft switching and input current quality
A second thread running through this work is reducing losses and electromagnetic interference through soft-switching techniques, using resonant tanks and a converter's own leakage inductance to achieve zero-voltage or zero-current switching on both the main switch and the output diode, which is usually the hardest component to protect from reverse-recovery losses in a high-gain design.
Alongside this, I've focused on keeping input current continuous and low-ripple, since a pulsating input current has real, harmful effects on sensitive renewable sources and disturbs their maximum-power-point tracking. Several of my designs use a genuinely current-fed input structure for exactly this reason, an important but often overlooked requirement for converters meant to sit directly behind a PV panel or fuel cell.
Scalable, multi-input, and multi-port architectures
More recently, this work has moved toward converters that can flexibly connect several sources and loads through a single power stage, rather than one converter per source. This includes extendable multi-input high step-up converters that scale to additional inputs without redesigning the existing ones, and multi-port bidirectional buck-boost converters built for EV charging stations that need to manage a grid connection, PV and wind sources, a battery or energy storage unit, and an EV, sometimes simultaneously.
That direction has led to integrated on-board EV chargers that combine multiple energy sources, grid, PV, and fuel cell, into a single reconfigurable charger, supporting vehicle-to-grid operation and regenerative braking, in some cases by repurposing a vehicle's own motor windings as the charger's power-factor-correction filter to avoid extra passive components altogether.
Benchmarking the field
Beyond individual converter designs, I've also contributed to a large comparative review of non-isolated high step-up DC–DC converters, evaluating topologies and boosting techniques across voltage gain, semiconductor stress, input current ripple, component count, and control complexity, aimed at giving researchers and engineers a consistent way to match a converter family to an application's actual requirements rather than relying on isolated, technique-specific claims.
AC–DC and DC–AC conversion
While most of the converters described above operate purely on the DC side, several of my projects extend into AC–DC and DC–AC conversion as well. Integrated on-board EV chargers, for instance, need a front-end AC–DC stage that rectifies grid power under unity power factor while also being able to run in reverse as a DC–AC inverter for vehicle-to-grid operation and regenerative braking, and I've designed and controlled these bidirectional AC–DC/DC–AC stages alongside the DC–DC stage they feed. Interlinking converters for hybrid microgrids are a similar case: the same power stage has to behave as an AC–DC rectifier or a DC–AC inverter depending on which direction power is flowing between the AC and DC subgrids.
Related systems-level work
This converter-design work sits alongside a related interest in how these converters function inside larger systems, including interlinking converters for hybrid AC/DC microgrids, where topology choices affect not just efficiency but grounding design, leakage current, and fault ride-through behavior.
Across all of these projects, the common thread is trying to extract more out of a converter's passive and active components at once, higher gain, lower stress, cleaner input current, fewer parts, simpler control, rather than treating these as separate problems to be solved one at a time.