Modelling and Control of a Matrix-Coupled PWM Power Converter with “All-in-One" Magnetics

Abstract

This thesis explores the modelling and control of matrix-coupled pulse width modulated (PWM) power converters. Combined with multiphase interleaving, the use of this “all-in-one” magnetic structure significantly reduces the size of the magnetic components, reduces the current ripple, and improves the transient response speed. By applying this technology to switched-mode power converter devices, they are able to achieve higher efficiency, higer power density, and faster tran sient repsonse than devices using discrete magnetics. We design and characterize a 4-phase matrix-coupled SEPIC converter with this "all-in-one" magnetic structure technology to verify the performance of this technology in this application. To control this 4-phase matrix-coupled SEPIC converter, we design and implement a hybrid digital-analog control architecture to leverage the four-phase topology to enable faster feedback response. This new control technology enables this power converter to achieve faster and more accurate tracking of a reference signals by increasing the effective sampling rate and control bandwidth of the device compared to existing controllers. We have shown that this device can support currents of up to 185 A for a 5V to 1V power conversion and achieve a maximum power density of more than 470/3 . These results are achieved while reducing our inductor size by a factor of four and achieving 9x faster transient response speeds when compared to a comparable discrete inductor device with similar output current ripple and device ratings. Combined with the hybrid digital-analog control architecture, the control is theorized to be able to track signals of up to 2x the chosen switching frequency, enabling rapid transient performance for highly dynamic loads such as high performance microcontrollers and enevelop tracking applications.