Evaluation of Phase-Shift Control for a High Voltage DC Supply using Multi-Level Cockcroft-Walton Multiplier

In this paper, a phase shift-controlled multilevel 2-stage half-wave Cockcroft-Walton multiplier is proposed for DC high voltage generation. The phase shift control scheme offers a wide range of voltage gain, fast dynamic response, low stress on switching devices, and smooth controllability. However, the conventional Pulse Width Modulation (PWM) scheme has limited voltage gain due to high-duty cycles and losses in parasitic elements. The discussed control scheme facilitates the generation of a three-level voltage signal, as opposed to the conventional two-level voltage signal produced by PWM. This advancement significantly alleviates the stress imposed on switching devices. The proposed topology uses six level 2-stage Cockcroft-Walton multiplier to achieve desired voltage of 27 kV with minimum voltage drop. The dynamic performance for load regulation and line regulation of the proposed structure is also evaluated in terms of overshoot, undershoot, settling time and steady-state error. It is observed that for line regulation and load regulation, phase shift control provides a better dynamic response, high voltage gain and lesser steady-state error.