A multi power band high voltage DC-DC converter

The conventional pulse-frequency-modulated (PFM) zero current switching (ZCS) series resonant (SR) inverter-fed high voltage (HV) dc power supplies have nearly zero switching loss. However, they have several limitations like; poor controllability at light load and large output voltage ripple at low switching frequencies. These limitations make them relatively less suitable for the applications which demand wide range of output voltage variation. To address these problems this paper proposes a multi-power-band high voltage dc-dc converter. The proposed converter has sixteen power bands (B₀ to B₁₅). It has essentially zero output power in the band B₀, lowest output power in band B₁ and highest output power in band B₁₅. Thus the output power of proposed converter increases in steps from its lowest value to highest value as power band is changed from B₁ to B₁₅. Switching frequency of converter is tuned within its narrow limits to adjust the output power within a power band. Proposed high voltage converter have several features such as wide range of control, less voltage ripple and low current stress on power switches. Simulation and experimental results confirm the excellent performance of proposed converter.