A DC-link Voltage magnitude-based Adaptive Controller Employed BLDC Motor Driver using an Asymmetrical Bridgeless Converter for Power Quality Enhancement

This article presents an asymmetrical AC–DC converter employing an adaptive controller–based Enhanced Power Quality (EPQ) Brushless Direct Current Motor Driver (BLDCMD). The AC–DC conversion stage consists of a bridgeless buck–boost converter for the positive half-cycle and a canonical cell converter for the negative half-cycle. The coordinated use of these two converters, operating under null-current switching, eliminates the need for several bulky and expensive components, resulting in a lighter, more compact, and cost-effective circuit. Furthermore, the study presents an adaptive Proportional–Integral (PI) controller capable of automatically adjusting its control parameters in response to variations in the DC-link voltage. This adaptability helps maintain a high power factor even under fluctuating DC-link conditions. The article also provides detailed mathematical modelling and a stability analysis of the proposed AC–DC converter using Bode plots and pole-zero (P–Z) maps. To validate the performance of the BLDCMD system, both dynamic and steady-state results are thoroughly presented and discussed.