Enhanced two-stage (photovoltaic-diesel) pumping system using DC-link voltage based speed reference and backstepping MPPT controller

A trailer-mounted two-stage booster mechanical pumping system has been constructed for use in evacuation of large vacuum vessels in remote locations. The pumping system is composed of three nominal 1500-cm air-cooled Roots blowers and four nominal 150-cfm mechanical pumps. It includes a high conductance cryogenic baffle, a self-contained helium leak detection station with a high speed oil diffusion pump, a liquid cryogenic system for supply of cryogenic fluids to the two cryogenic traps, and dry gas for use in backfilling of vessels as required. A programmed start-up and run-down control is provided for simplified, safe operation of the pumping system. A simplified method of presenting pumping system performance and a design analysis procedure for matching of mechanical pumps to the boosters are described.

This work presents a proposal for the expansion of a water treatment system inside an underground mine, and thus optimize the water resource present in the mining operation. For this purpose, the design parameters of an existing two-stage pumping system were determined and the hydrogeological conditions of the mine were analyzed. It was determined that a 500 HP pump was necessary that can deliver a dynamic head of 75 meters. Finally, an evaluation of the economic feasibility of the expansion design towards a three-stage pumping system with sedimentary pumps was carried out for its implementation. An approximate CAPEX of the pumping system of US$ 13,571,442 was determined; and an OPEX of 0.299 US$/m 3 .Likewise, based on the estimated VPT of the mineral, the reserve report, the CAPEX of the pumping system and other projects, a NPV of the mine of US$ 65,562,057 and an IRR of 18.10% was estimated.

This article proposes an efficient control scheme for a two-stage water pumping system. The proposed method has three primary objectives. The first objective is to attain the maximum power point (MPP), which realizes using an improved MPP tracking algorithm. The second objective is to regulate the dc-link voltage, which is usually obtained by a PI controller. The PI controller is sensitive to parameter variation making the system unstable during dynamic conditions. Therefore, this article proposes a sliding mode controller (SMC) for dc-link voltage regulation. The proposed SMC also employs a continuous switching function to reduce the chattering issue. The last objective is to estimate the dc-link voltage. It is achieved using a mathematical model-based design approach considering the dynamics of the dc–dc converter. MATLAB Simulink and experimental analysis are used to validate the overall system performance. The proposed method accurately estimates and regulates the dc-link voltage with reduced oscillations under various dynamic conditions. The merit of the proposed system is to eliminate the need for a dc-link voltage sensor and speed encoder. Therefore, the proposed method is economical and efficient for water pumping applications.

A high-performance control scheme for photovoltaic pumping system under sudden irradiance and load changes

This paper presents a novel methodology for an optimal operation of a photovoltaic (PV) pumping system. It consists of Photovoltaic (PV) generator, DC motor pump and Boost converter for maximum power point tracking MPPT. The proposed control strategy involves nonlinear controller designed, using robust sliding mode design technique. To reduce the PV pumping system cost, a high gain observer is designed, it needs only the solar array voltage sensor which allows estimating on-line the unmeasured states variables of the photovoltaic pumping system. Some reliable simulation results are provided in order to demonstrate the robustness and efficiency of the proposed approach.

This paper examines a two-stage solar-powered water pumping system operated by a reluctance synchronous motor drive (RelSyMD) with the grid integration. This configuration also focuses on smart sharing of the power between solar PV array and grid supply. It consists of a bidirectional voltage source converter instead of a diode bridge rectifier, which also feeds power from DC link to the grid. Moreover, an intermediate DC-DC converter is used for optimization of PV array power, so that in spite of change in insolation, the DC link voltage is kept constant. When there is no need for water pumping, or if the power of the PV array exceeds the need of the pump, this system allows farmers to profit financially by feeding excess power to the grid. The system is simulated and modeled in the MATLAB environment. There are four distinct modes of operation recognized based on the availability of power sources and sun radiation. The response of the system in these operating conditions is simulated and results are presented in this work.

This paper presents a robust fuzzy control scheme for maximum power tracking of a photovoltaic (PV) pumping system dedicated to domestic use. This system is composed of a photovoltaic generator (PVG) supplying via a DC-DC boost converter, a DC motor coupled to a centrifugal pump. A knowledge dynamic model of the pumping system is firstly developed leading to a Takagi Sugeno (TS) representation by a simple convex polytopic transformation. This approach allows to reproduce the dynamic behavior of the system with accuracy over a wide operating range. Then, a robust T-S fuzzy MPPT controller is designed to track the reference speed and achieve an optimal operation of the photovoltaic pumping system. The proposed controller generates the optimal duty cycle to match the motor-pump impedance with the PV generator via a DC-DC converter, and thus, maximizes the quantity of water pumped daily. Finally, simulation results which take into account all changes in climatic conditions are presented for both transient and steady state operation.

Impact of shadow on the performances of a domestic photovoltaic pumping system incorporating an MPPT control: A case study in Bejaia, North Algeria

An effective control scheme of a standalone water pumping system powered by a photovoltaic (PV) source is presented in this contribution. The proposed solution aims to achieve robust control of the two stages of the pumping system. Therefore, a cascaded controller is designed for maximum power point tracking (MPPT), in which a perturb and observe (P&O) algorithm provides the optimal PV voltage. Then, a sliding mode controller (SMC) based on PWM is designed to regulate the input PV voltage. Subsequently, a fuzzy logic controller is designed to generate the reference speed which regulates the DC-bus voltage. Finally, predictive torque control (PTC) is applied to drive the induction motor (IM). In order to confirm the effectiveness of the proposed control methods, a simulation has been done within a dynamic change of irradiance.

This paper deals with the sliding mode control of photovoltaic pumping system using an indirect field oriented control of the induction motor. The pumping system is composed by a photovoltaic generator, an output DC capacitor, an inverter which supplies an induction motor which drives the shaft of a centrifugal pump. After the modeling of the different components of the pumping system the sliding mode control is choosing to be apply in this work thinks to advantages, which present compared to conventional PI controller. Then an (MPPT) algorithm of the maximum power point tracking is used to determine the speed reference of induction motor from the value of illumination. Finally, simulation and experimental results are presented to show the effectiveness of the proposed control strategies.

A single-switch nonisolated dc/dc converter for a stand-alone photovoltaic (PV)-battery-powered pump system is proposed in this paper. The converter is formed by combining a buck converter with a buck-boost converter. This integration also resulted in reduced repeated power processing, hence improving the conversion efficiency. With only a single transistor, the converter is able to perform three tasks simultaneously, namely, maximum-power-point tracking (MPPT), battery charging, and driving the pump at constant flow rate. To achieve these control objectives, the two inductors operate in different modes such that variable switching frequency control and duty cycle control can be used to manage MPPT and output voltage regulation, respectively. The battery in the converter provides a more steady dc-link voltage as compared to that of a conventional single-stage converter and hence mitigates the high voltage stress problem. Experimental results of a 14-W laboratory prototype converter with a maximum efficiency of 92% confirmed the performance of the proposed converter when used in a PV-battery pump system.

Recent day's Non-conventional Energy source plays an important role on the agriculture sector. The flow rate of most water pumping systems is mostly determined by environmental circumstances. A variety of MPPT methods and control strategies are available to estimate water pumping system efficiency under various atmospheric conditions. This paper includes a thorough examination of the various MPPT and control mechanisms utilized in solar photovoltaic pumping systems (SPVPS). The majority of the authors discussed several forms of MPPT methods and control strategies for an SPVPS system, as well as their application. For each MPPT and control strategy, there are advantages and disadvantages. As a result, a review of the literature on these MPPT and control techniques is critical for pumping applications. Different components influencing solar photo voltaic system execution for example sunlight-based irradiance, Temperature, Partial shading effects it's one of the main drawbacks of the photo voltaic system. The partial shade condition of trees positioned on the inner of the Agriculture Land has had a significant impact on the agricultural area. As a result, scientists all around the world are concentrating on the MPPT and control strategy of solar photovoltaic systems.

In this paper, we present an approach for modeling, control and optimization of a photovoltaic pumping system which contains a pv generator, DC-DC boost converter, MPPT controller, DC-AC inverter and a BLDC motor. We use an intelligent control method for searching the maximum power point (MPP). This method uses a fuzzy logic controller applied to a drive a DC-DC converter to an optimal operating point using PV panel's measured variables. The PWM signals are generated by the interaction of the motor speed closed-loop system and the current hysteresis. The motor reference current is compared with the motor speed feedback signal. The considered model has been implemented in Matlab/simulink environment. The results show the effectiveness of the proposed method to increase the performance of the water pumping system.

This paper describes the implementation of a renewable energy system that operates independently. It comprises a photovoltaic generator (PV) that supplies power to a solar pumping system, driven by a permanent magnet direct current motor (PMDC) via a DC-DC Buck converter. Consequently, the objective is to maintain steady operation with continuous power supply despite changes in two environmental parameters, including solar irradiation and absolute temperature. The maximal power extraction of the PV panel using the usual perturbation and observation (P&O) technique achieves this objective. This method must provide appropriate duty cycle control for the DC-DC buck converter when the user-selected Fixed-Step Size (FSS) is used, unfortunately, selecting an insufficient fixed-step size led to a power ripple issue with the PV panel. Incorporating a new Variable Step-Size (VSS) into the traditional P&O algorithm shows the occurrence of the enhanced P&O-MPPT control approach. The proposed technique is validated by utilizing the PROTEUS/ISIS software. For various climatic situations, the results demonstrate that the proposed control technique is preferable to the one based on the standard P&O-MPPT.

Theoretical and experimental analysis of the behaviour of a photovoltaic pumping system