The energy utilization efficiency of commercial photovoltaic (PV) pumping systems can be significantly improved by employing simple perturb and observe (P&O) maximum power point tracking algorithms. Two such P&O implementation techniques, reference voltage perturbation and direct duty ratio perturbation, are commonly utilized in the literature but no clear criteria for the suitable choice of method or algorithm parameters have been presented. This paper presents a detailed theoretical and experimental comparison of the two P&O implementation techniques on the basis of system stability, performance characteristics, and energy utilization for standalone PV pumping systems. The influence of algorithm parameters on system behavior is investigated and the various advantages and drawbacks of each technique are identified for different weather conditions. Practical results obtained using a 1080-Wp PV array connected to a 1-kW permanent magnet dc motor-centrifugal pump set show very good agreement with the theoretical analysis and numerical simulations.

An efficient, cost-effective maximum power point tracking (MPPT) algorithm is required to improve the energy utilization efficiency of low power photovoltaic (PV) systems. This paper presents an experimental evaluation of the incremental conductance MPPT algorithm when employed by a standalone PV pumping system, using an experimental installation comprised of a 1080-Wp photovoltaic array connected to a 1-kW permanent magnet dc motor-centrifugal pump set. Particular focus is given to the evaluation of the two commonly utilized implementation techniques: reference voltage perturbation and direct duty ratio perturbation. The influence of algorithm parameters on system behavior is investigated and the energy utilization efficiency is calculated for different weather conditions. The performance of the incremental conductance algorithm is compared to that of the commonly used perturb and observe MPPT algorithm and the various advantages and drawbacks of each technique are identified.

The requirement for high-voltage gain step-up dc-dc converters is increasingly becoming 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 nonisolated interleaved dc-dc boost converter with zero voltage switching. 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 > 10 × voltage gains without the need to apply extreme modulation signals to the pulse width modulation circuit.

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.

This paper presents a comparative investigation of the performance characteristics of a directly connected photovoltaic (PV) pumping system and a scheme utilizing a constant voltage maximum power point tracking algorithm. A simple and accurate model is developed for each individual component of the system based on its measured characteristics and the system is simulated numerically. System performance is analyzed and energy utilization efficiency is calculated for different weather conditions. A detailed comparison identifying the advantages and drawbacks of each technique is presented. Experimental results obtained using a 1080-Wp PV array connected to a 1-kW permanent magnet dc motor-centrifugal pump set show very good agreement with the numerical simulation of the systems.

One of the most commonly utilised maximum power point tracking (MPPT) algorithms for photovoltaic (PV) generators is the incremental conductance (INC) algorithm. Yet, the operating characteristics of this algorithm at high perturbation frequencies, when the system response to MPPT perturbations is never allowed to settle, have not been addressed in the literature. This study characterises system behaviour in this operating mode experimentally for a standalone PV system with a dc motor–pump load. Results show that the INC algorithm operating at a high perturbation rate offers higher energy utilisation efficiency and better system performance despite the resulting non‐periodic waveforms of the system.