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

Design and implementation of a dual-input single-output photovoltaic converter

In many solar inverters, a dc/dc converter is mainly located between the solar arrays and the inverter. This study presents an enhanced maximum power point tracking (MPPT) algorithm for photovoltaic (PV) systems that drives solar array voltages to track a reference value and decreases fluctuations and oscillations in PV voltage. Different from the previously presented methods, a novel MPPT method is proposed that ensures tracking accuracy by considering output voltage in addition to input voltage and currents. The proposed method detects dI/dV variations, compares the output voltage with the desired reference to shift operation mode and refreshes step size. The digital filtering, enhanced PI, and perturb-and-observe (P&O) tracking features of the proposed MPPT method make it robust to mitigate source fluctuations and sensitivity to partial shading based oscillations. In order to validate the success of the proposed method, a test rig has been installed with dual boost converters. The performance improvements have been verified by both simulation and experimental results that are compared to InCon and P&O MPPT methods. It is also confirmed by experimental results that the proposed MPPT method provides robust control capability in terms of tracking the reference voltage and rejecting the effects of various shading situations on solar arrays