Dynamic Phasor-Based Modeling and Analysis of Dual-Loop Controlled DC-DC Converters

Abstract

To design efficient and reliable direct current-based energy systems, telecommunication equipment, transportation systems, and healthcare devices, accurate DC-DC converter models are required. In addition, computationally efficient models are required to expeditiously simulate large DC systems (with multiple converters). In this paper, the dynamic phasor (DP) method is used to develop computationally efficient multi-frequency average models of dual-loop controlled DC-DC converters (buck, boost, and buck-boost) which are suitable for accurate modeling and analysis of ripples. By recognizing that high frequency components of inductor current and capacitor voltage are small compared to DC components, in addition to being equal to zero over a switching cycle, the control system is designed to target the average value of current and voltage. This simplifies the control process compared to existing DP-based closed-loop models of DC-DC converters. Small-signal modeling technique is used to obtain suitable control gains. The DP-based DC-DC converter models built on MATLAB/Simulink are validated against detailed models built on Simulink/Simscape. Simulation results confirm the effectiveness of the proposed control strategy as well as the huge computational advantage of DP-based DC-DC converter models over detailed models.