This paper presents a capacitorless active output filter (CLAOF) for high-performance VSCF motor-drive systems in aerospace applications. The topology removes all electrolytic and film capacitors and suppresses harmonics through active voltage injection using three planar 1:1 transformers driven by solid-state full bridges. The CLAOF compensates low-order and switching harmonics in real time, producing near-sinusoidal output voltages independent of load. A carrier-synchronized gating method ensures volt-second balance across each transformer, preventing magnetic bias without dc-blocking capacitors. Analysis shows that the dominant 6p±1 harmonics are effectively canceled. Eliminating capacitors greatly improves reliability, reduces weight, and increases power density, offering a scalable and fault-tolerant solution for next-generation aerospace power systems.
