Small-signal modeling of current-mode controlled modular DC-DC converters using the state-space algebraic approach

Small-signal models are useful tools to preliminary understand the dynamics of interconnected systems like modular dc-dc converters which find a wide range of industrial applications. This work proposes a state-space-based averaged small-signal model in symbolic form for a peak current-mode controlled parallel-input/parallel-output buck converter operating in the continuous-conduction mode. In modeling the converter power-stage each module is independently represented. For modeling the current-mode control the state-space algebraic approach is used to incorporate the current-mode control-law into the power-stage equations. For each module two parasitic elements in addition to the current-loop sampling action are included in the derivation. Furthermore, the control-to-output voltage transfer functions are presented in symbolic form for two cases of interest: the first when the converter has two non-identical modules to study the effect of inductor mismatch, and the second when the converter is composed of n-connected identical modules to assess the effect of varying the number of modules. All responses from PSIM cycle-by-cycle simulations are in good agreement with the mathematical model predictions up to half the switching frequency

Input current control of boost converters using current-mode controller integrated with linear quadratic regulator

The application of power electronic converter in the renewable energy systems significantly increases their efficiencies by maintaining the operation of these systems at the optimal operating points, therefore, absorbing the maximum available power from the renewable sources all the time. In this paper, the small-signal models of the open-loop, current-mode controlled boost converter are derived. In addition, both the Current Mode Control (CMC) and the Linear Quadratic Regulator (LQR) methods are combined to design a controller that forces the input current of the converter to follow accurately a reference current, which could be generated using maximum power point tracking (MPPT) algorithms. The controller performance is tested under transient conditions and with disturbance signals using MATLAB/Simulink simulation package. The simulation results indicate that both a good response and disturbance rejection are achieved in tested conditions