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the requirement for high voltage gain step-up DC-DC converters is becoming increasingly important in many modern power supply applications. They are an essential power conversion stage in systems such as grid connected renewables and electric vehicles. Unfortunately, achieving a low cost, high efficiency, power dense, step up converter with high voltage gain is not a trivial task; yet they are highly desirable when aiming for a green power supply solution. For this reason, this paper presents a new non-isolated interleaved dc-dc boost converter with Zero-Voltage-Switching (ZVS). The proposed converter is designed around a coupled inductor, with an active clamping circuit arrangement to recycle the coupled inductor leakage energy and reduce the voltage stress on the semiconductor devices. The lack of isolation transformer improves the power density of the system. Likewise, the interleaved circuit allows for high efficiency over a broad range of operating conditions. The theoretical behavior of the power converter is fully described, and the performance of the circuit is validated through experimental results. Importantly, the circuit is capable of achieving >10X voltage gains without the need to apply extreme modulation signals to the pulse width modulation (PWM) circuit. Index Terms-High-step-up, interleaved boost converter, non-isolated, winding coupled inductors, zero voltage switching (ZVS) I. INTRODUCTION ANY green power supply applications call for a high efficiency, high step-up dc-dc converter in the power conversion stage. Typical examples include electric drives [1], grid connected inverters [2-4], electric vehicle drive trains [5], uninterruptible power supplies system (UPS) [6], telecommunication power systems, and high intensity discharge lamps [7]. Furthermore, high voltage step up gains are increasingly required when the system is powered by low voltage energy sources such as Li-ion batteries, solar arrays and fuel cells.Theoretically, conventional non-isolated boost and buck-boost converters are the simplest pulse width modulation (PWM) controlled topologies for voltage step-up. However, these converters typically have to operate under extreme duty ratios to achieve high voltage gains. As a consequence, significant voltage and current stresses are incurred by the converter devices and poor dynamic characteristics can result in the controlled output response. Furthermore, the output diodes often sustain short, but high amplitude, current M

The high level of penetration of photovoltaic (PV) systems into electric power grids increases rapidly due to many merits of such promising technology. In the simulation investigation of PV systems, an accurate PV model is vital, where it plays an important role through the dynamic analysis of these systems. The mathematical model of the PV module is a nonlinear I-V characteristic including many unknown parameters as data provided by the PV manufacturers' are inadequate. This paper introduces a novel application of the whale optimisation algorithm (WOA) for estimating the parameters of the single, double, and three diode PV models of a PV module. The WOA-based PV models are validated by the simulation results, which are carried out under various environmental conditions using MATLAB program. The effectiveness of the WOA-based PV models is checked by comparing their results with that obtained using other optimisation methods. To obtain a realistic study, these simulation outcomes are compared with the experimental outcomes of a Kyocera KC200GT PV module. The WOA-based PV model is efficiently evaluated by comparing the absolute current error of this model with that obtained using other PV models. Using this meta-heuristic algorithm application, an accurate PV model can be obtained.

High step-up dc-dc converters are increasingly required in many industrial applications. Conventional topologies operate at extreme duty cycle, high semiconductor voltage stress, switching loss, and diode reverse recovery problems. This paper presents a new non-isolated high gain, boost converter operating with a modest duty cycle by integrating a coupled inductor and switched capacitor technique. Importantly, the structure of the high voltage side, together with the switched capacitor, reduces the voltage stress of the power switch to less than one third of the output voltage, which in turn helps to reduce the conduction loss by using a low on-resistance switch. The diode voltage stress is less than the output voltage which facilitates faster recovery. Furthermore, the converter employs a passive clamp circuit to recycle the leakage energy. The main switch achieves zero current switching (ZCS) turn-on performance and all diodes achieve (ZCS) turn off reducing reverse recovery related losses. As a result, the circuit exhibits high efficiency performance; which is essential for most modern power electronic applications. In this paper, the operational principle and performance characteristics of the proposed converter is presented and validated experimentally with a 250 W, 20 V input voltage / 190 V output voltage prototype circuit.

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The perturb and observe (P&O) algorithm is one of the most commonly utilized maximum power point tracking (MPPT) control schemes for photovoltaic (PV) generators. However, the operation of this algorithm at high perturbation frequencies, when the system response to MPPT perturbations is never allowed to settle, has not been given adequate attention in the literature. This paper characterizes system behavior in this mode of operation for standalone PV systems feeding resistive loads and motor-pump loads. Simulation and experimental results show that the P&O algorithm operating at a high perturbation frequency may offer higher energy utilization efficiency and better system performance, despite the resulting nonperiodic waveforms of the system.Index Terms-DC-DC power conversion, maximum power point tracking (MPPT), photovoltaic (PV) power systems, PV pumping. I. INTRODUCTIONA NUMBER of maximum power point tracking (MPPT) algorithms with different levels of complexity, efficiency, and implementation costs, have been proposed in the literature for standalone and grid-connected photovoltaic (PV) applications. Most of these algorithms have been comprehensively reviewed in a number of review papers [1]- [5]. The simplest and cheapest MPPT method maintains the PV array operation at a constant voltage [6] equal to its standard test conditions maximum power point (MPP) voltage provided by the manufacturer. At a small increase in implementation cost, the energy utilization efficiency can be significantly improved by employing the perturb and observe (P&O) MPPT technique. This is a simple algorithm that does not require previous knowledge of the PV generator characteristics or the measurement of solar intensity and cell temperature and is easy to implement with analog and digital circuits. The algorithm regularly perturbs the operating point of the PV generator by increasing or decreasing a con-Manuscript