A low-cost and flexible architecture of digitally controlled DC-DC converter to improve dynamic performance

Authors: ABDOLSAMAD HAMIDI, ARASH AHMADI, SHAHRAM KARIMI

Abstract: One type of DC-DC converters is dual transistor forward converter. In this article, a low-cost architecture of a digital controller for dual transistor forward converter is presented. This architecture is designed by using the finite set model predictive control technique. Based on this approach, a low-cost fixed-point arithmetic architecture with minimum functional units is presented to find the optimum switching time at each sampling point. Charge balance control method is utilized to improve the dynamic performance of the transient response. The proposed architecture is implemented and realized by using a field-programmable gate array (FPGA) platform to evaluate the precision of the fixed-point calculation. Several cases for different loading conditions for different word lengths are practically investigated and the proposed digital controller shows a minimum voltage overshoot--undershoot and short settling time under load-changing situations. Compared with other controllers, the presented work provides a better dynamic performance and lower implementation cost.

Keywords: Forward converter, digital controller, predictive control, fixed-point computations, low-cost architecture, word length

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