Forward–Flyback Converter With Cockcroft–Walton Voltage Multiplier in DCM: Steady-State Analysis Considering the Parasitic Capacitances to Achieve the Optimal Valley-Switching Operation With 95.11% Efficiency at 3 kV/1.5 W

Nowadays, electrohydrodynamic (EHD) cooling systems are considered a good alternative to rotary fans and heatsinks from industrial electronic applications due to their robustness, high performance, and low weight. The EHD load tested along this article demands high voltage (3 kV) and very low current (500
$\mu \text{A}$
) to produce the corona discharge and the airflow. The forward–flyback converter with Cockcroft–Walton voltage multiplier (FFCWVM) is proposed in this article as a suitable topology to supply EHD loads. The parasitic capacitances are considered throughout the steady-state analysis, leading to new operating stages and allowing for a very accurate mathematical modeling of the main resonant intervals. Consequently, the impact of a slow voltage transition in the functioning of the circuit is analyzed and the optimal valley-switching operation is calculated analytically. Finally, the theoretical analysis is validated by means of simulations and experimental results, achieving a very high efficiency (95.11%) for such low output power (1.5 W).