Summary
Modern power systems are increasingly dominated by power electronics-based converters. Power converters are present in the prevailing renewable energy generators (wind and solar PV), energy storage interfaces, high voltage direct current (HVDC) transmission systems, Flexible Alternating Current Transmission Systems (FACTS), electrical vehicle chargers and industrial drives, among others.

 Worldwide, we are witnessing a system transformation towards a power electronics dominated system at high, medium and low voltage levels. This is changing the structure of generation, transmission and distribution systems. While the actual penetration is very significant, the trend is clearly increasing and the penetration of power electronics is going to arrive to very high ratios. These systems are characterized by full controllability, fast dynamics, limited overload capacity, and very limited inertia. 

This shift introduces new challenges, such as stability issues, complex control interactions, protection schemes, and the integration of grid-forming and grid-following converters. 

The talk will introduce the topics: 
(1) The role of power electronics and grid forming/following converters in MMC and renewable power plants; 
(2) Short-circuit calculations and grid equivalent representations; 
(3) Grid forming loads; 
(4) Hybrid AC-DC grids, including the grid-of-grids concept, with multiple AC and DC subgrids that can support each other while firewalling the propagation of severe disturbances.

Summary
Is it feasible to develop a single-stage DC-DC converter with an 800V input and 4,000A output? This keynote argues that not only is it feasible — it is the only scalable path forward.

Meeting the power demands of AI datacenters, now reaching the megawatt-per-rack scale, requires a paradigm shift in power conversion. High input voltages such as 800V (or ±400V) are essential to reduce distribution losses, while next-generation AI accelerators demand output currents exceeding 4,000A and slew rates of 4,000A/μs — specifications that push conventional multi-stage approaches to their physical limits.

Existing solutions — Intermediate Bus Architectures, IVRs, and TLVR-based regulators — face fundamental scaling limits in current density and conversion ratio. DPx is a direct power conversion architecture that eliminates the intermediate bus entirely, achieving conversion ratios exceeding 800:1 in a single stage. Built around the Segmented Winding Transformer (SWT), it enables intrinsic input voltage balancing for high-voltage stacking and intrinsic output current balancing for the parallel operation of hundreds of conversion cells — with efficiencies exceeding 90% and current densities 3x higher than conventional solutions.

Summary
Over the last five decades, power semiconductor technology has progressed from low-voltage silicon bipolar junction transistors (BJTs) to advanced wide-bandgap devices capable of operating from tens of volts to multi-kilovolt ranges with unprecedented switching performance. Key technology milestones include planar and trench power MOSFETs, fast recovery and soft-switching freewheeling diodes (FWDs), insulated gate bipolar transistors (IGBTs), superjunction structures, silicon carbide (SiC) MOSFETs and JFETs, and gallium nitride (GaN) HEMTs.

This continuous evolution has been driven by the demand for lower conduction and switching losses, higher power density, improved thermal performance, and increased reliability. Silicon-based devices enabled the large-scale deployment of efficient motor drives, switched-mode power supplies, traction systems, and renewable energy converters. The introduction of wide-bandgap semiconductors significantly increased achievable switching frequencies, junction temperatures, and breakdown electric fields while reducing passive component size and overall system losses.

Today, normally-off GaN HEMTs, bidirectional GaN switches (BDS), and advanced SiC JFET architectures are enabling a new generation of power conversion topologies, including ultra-high-frequency resonant converters, matrix converters, solid-state circuit breakers, and highly integrated multi-level architectures. These devices are no longer merely incremental component improvements; they are becoming key enablers for fundamentally new converter concepts and application domains in electrification, AI infrastructure, renewable energy, and humanoid robots.