Differential Evolution Based Algorithm for Optimal Current Ripple Cancelation in an Unequal Interleaved Power Converter

This paper proposes an optimal methodology based on the Differential Evolution algorithm for obtaining the set of duty cycles of a recently proposed power electronics converter with input current ripple cancelation capability. The converter understudy was recently introduced to the state-of-the-art as the interleaved connection of two unequal converters to achieve low input current ripple. A latter contribution proposed a so-called proportional strategy. The strategy can be described as the equations to relate the duty cycles of the unequal power stages. This article proposes a third switching strategy that provides a lower input current ripple than the proportional strategy. This is made by considering duty cycles independently of each other instead of proportionally. The proposed method uses the Differential Evolution algorithm to determine the optimal switching pattern that allows high quality at the input current side, given the reactive components, the switching frequency, and power levels. The mathematical model of the converter is analyzed, and thus, the decision variables and the optimization problem are well set. The proposed methodology is validated through numerical experimentation, which shows that the proposed method achieves lower input current ripples than the proportional strategy.

A New Two Switched-Impedance Network for High Ratio Quasi-Z-Source Inverter

The increasing demand and widespread of renewable energy inherently compel the development of power electronics converter as an interface between consumers and the energy source/s. This paper presents a new two switched-impedance networks qZSI converter called High Ratio Two Switched-impedance quasi-Z-Source Inverter (HR2SZ-qZSI). Compared with the previous topology, this proposed HR2SZ-qZSI topology can achieve higher voltage gain with lower shoot-through duty ratio, and a higher boost factor. This paper also discusses comparative analysis between the previous topology and the proposed HR2SZ-qZSI topology. Furthermore, the simulation and experimental data are presented to prove the theoretical analysis of the proposed HR2SZ-qZSI topology. Despite the additional components needed, it accentuates that this proposed converter retains all features of qZSI: common ground point between the dc source and converter and smooth input current operation. Furthermore, almost all the devices rating including capacitor and diode voltage, and inductor current ripple are lower than the preceding relevant two switched-impedance qZSI family. Accordingly, this proposed HR2SZ-qZSI clearly a good power conditioning alternative for renewable generation system.

On the Existence and Uniqueness of the ODE Solution and Its Approximation Using the Means Averaging Approach for the Class of Power Electronic Converters

Power electronic converters are mathematically represented by a system of ordinary differential equations discontinuous right-hand side that does not verify the conditions of the Cauchy-Lipschitz Theorem. More generally, for the properties that characterize their discontinuous behavior, they represent a particular class of systems on which little has been investigated over the years. The purpose of the paper is to prove the existence of at least one global solution in Filippov’s sense to the Cauchy problem related to the mathematical model of a power converter and also to calculate the error in norm between this solution and the integral of its averaged approximation. The main results are the proof of this theorem and the analytical formulation that provides to calculate the cited error. The demonstration starts by a proof of local existence provided by Filippov himself and already present in the literature for a particular class of systems and this demonstration is generalized to the class of electronic power converters, exploiting the non-chattering property of this class of systems. The obtained results are extremely useful for estimating the accuracy of the averaged model used for analysis or control of the effective system. In the paper, the goodness of the analytical proof is supported by experimental tests carried out on a converter prototype representing the class of power electronics converter.

A new MPPT technique for optimal and efficient monitoring in case of environmental or load conditions variation

Due to the very high initial investment cost of photovoltaic systems and their low conversion efficiency, it is essential to operate PV generators at the point of maximum power (MPP). Within this framework, our first objective in this thesis is to develop and improve the PV system, contributing to optimizing the PV panels' energy through a DC-DC power electronics converter. For this reason, a further improvement of the incremental conductance technique is proposed to improve the MPP tracking capability of the PV system when the level of solar irradiation is suddenly increased or when the load undergoes variations. The new technique includes two processing phases: a calculation phase to improve the tracking speed and a regulation phase to improve MPP tracking efficiency. In order to evaluate its performance, the proposed new method is compared to other methods, namely the Incremental conventional conductance (INC) technique and the Modified Variable Size Incremental conductance (M-INC) technique. The results show that the proposed technique's overall tracking speed is 3.7 times faster than the conventional INC technique and 1.52 times faster than the modified INC technique. Also, the tracking power losses with the proposed technique are lower compared to other techniques. In terms of overall efficiency, the proposed technique is the most efficient with an efficiency of 94.83%, followed by the modified technique with an overall efficiency of 87.94%. In comparison, the conventional INC technique's efficiency is the lowest and does not exceed 83.33%.

A NOVEL APPROACH ON POWER ELECTRONICS CONVERTER BASED ADAPTER

Hybrid Portable Universal Adapter is very efficient and new technology which has capable of taking DC and AC input both and can provide constant DC output. This paper presents renewable energy like Solar panels as DC source and normal AC (230V RMS) source. It has controlled circuit incorporated in it to step down AC voltage without using transformer. This model can give constant DC output of 5v. This circuit has parallel converter circuit which converts AC to DC and DC to DC as well. This adapter can be carried easily and we can use it to charge our mobile phones or any power bank