A robust MPPT approach based on first-order sliding mode for triple-junction photovoltaic power system supplying electric vehicle

Abstract

This paper studies the problem of the energy system optimization for photovoltaic (PV) generator supplying the electric vehicle. The used photovoltaic generator was conceived around a high-efficiency triple-junction solar cell InGaP/InGaAs/Ge. To adopt the photovoltaic generator to the load and to track the maximum power points, a DC–DC converter feeding the electric vehicle is used. Due to the nonlinearity of the PV generator’s electrical characteristics on the one hand and meteorological conditions variations and load changes, on the other hand, robust control approach is used. It is based on the sliding mode control (SMC) technique. The maximum power point tracking (MPPT) approach for a PV system is well detailed. Moreover, a stability analysis of this approach is carried out. The PV system used in the comparative study is made up of a resistive load, a boost converter, and a high efficiency PV generator. Standard test conditions, a step change in solar radiation with a constant temperature, a step change in temperature with a constant solar radiation, a step change in load and solar radiation with a constant temperature, simultaneous step changes in load, temperature, and solar radiation, and partial shading conditions are the seven case studies that are investigated. They have the aim of evaluating the effectiveness and advantages of the SMC algorithm in comparison to those of perturb and observe (P and O) and three meta-heuristic algorithms. The latters are the particle swarm optimization (PSO), flower pollination (FPA) and the cuckoo search algorithm (CSA). Obtained results show that the SMC algorithm has the ability to sufficiently and rapidly track the maximum power points in the aforementioned cases. As a result, it is used in electric vehicles. The traction part of the electric vehicle is built around a three-phase permanent magnet motor (PMSM). The control strategy is based on indirect, field-oriented control. The conceived system and the control algorithms are all implemented in Matlab/Simulink. Significant results for a wide range of speeds, including the two operating modes under step changes in environmental conditions and under strong partial shading conditions, are presented and discussed.