| Abstract |
High voltage power supply with pulse load (125 KHz and 10 % duty cycle) condition is investigated
which is of interest for applications like radar power supplies with output voltage of 22 KV. The
performance specifications with this type of power supplies are very stringent demanding tight
regulation (< 0.01 %) and high efficiency (> 85%). The solution to this problem as a single stage
converter is very difficult. In converters operating at high voltage and high frequency the insulation
failure of high voltage transformer is very common. Skin and proximity effect result in higher power
losses. Because of high turn’s ratio, the winding capacitance results in delays and large current spikes.
Hence a two level converter has been contemplated. One stage of it, namely, Base power supply
(BPS), operates at low frequency and produces majority of the output voltage and power. The other
one, namely, fast power supply (FPS), operating at high frequency and low output voltage supplies the
remaining power and takes care of the transient variations of line and load. The final output voltage is
obtained as sum of the outputs of BPS & FPS. The combination of the two stages can satisfy the pulse
load specifications. Each of the BPS & FPS use phase modulated-series resonant converter as the
power-processing unit with zero voltage switching (ZVS). The analysis of the voltage and power
division between BPS & FPS has been done for the proposed topology. It is simulated for a power
level of 600 watts and an output voltage of 1 KV as a prototype. It has been studied under various
operating conditions of line and load. Simulation results are validated by experimental results. |
