In recent trends for smart materials which are evolving in the last decade such as polymer actuators have gained potential over many traditional conventional actuators for its unique properties such as lightweight, high flexibility and lower power consumption etc. These instruments are ideally considered to be capacitive load by nature and should be driven with a specific sequence of signals. A low power high voltage power supply is required for driving these loads for charging and discharging in a specified charge and discharge time with higher efficiency, low component count. A high voltage low power (HVLP) flyback converter is chosen for its low component count and transformer isolation with high switching frequency for high voltage charging and discharging of the capacitive load. The transformer parasitics such as leakage inductance and self-capacitance along with other semiconductor parasitics significantly affect the performance of the converter. Planar Transformers are popularly used over conventional wire-wound transformers for its design accuracy, high power density and low transformer parasitics.

Different transformer winding architectures are explored to choose transformer design architecture with minimum parasitics. Two planar transformer models are designed, a rectangular winding planar transformer with an ELP core geometry is evaluated for non-interleaved winding architecture with turns ratio n = 18 and a spiral winding planar transformer with turns ratio n = 20 is evaluated for a non-interleaved, partially interleaved and interleaved winding architectures for a high voltage low power flyback converter. The analytical computation for leakage inductance is derived using MMF distribution and the estimation of parasitic capacitance is determined in Finite Element Analysis (FEA) simulation using Ansys Maxwell. The frequency response analyzer (FRA) is utilised to characterise the designed transformers and the impedance parameters of the transformer models with different winding architecture are obtained.

The results obtained from analytical computation, 2D FEA and transformer characterisation measurement are compared. The designed HVLP rectangular and spiral winding PT are fabricated and tested with high voltage flyback converter prototype with capacitive load for 2.5 kV / 5 W. The effect of the transformer parasitics in the inductor current and switch voltage for two transformer models and various winding architectures are observed and verified from the experimentally observed waveforms.