DC Electronic Load Research Articles

Assessment of Data Capture Conditions Effect on Reverse Electrodialysis Process Using a DC Electronic Load

Reverse electrodialysis (RED), an emerging membrane-based technology, harnesses salinity gradient energy for sustainable power generation. Accurate characterization of electrical parameters in RED stacks is crucial to monitoring its performance and exploring possible applications. In this study, a DC electronic load module (DCELM) is implemented in a constant current condition (CC mode) for characterization of lab scale RED process, using a RED prototype in-house designed and manufactured (RU1), at different data capture setups (DCS), on which the total number of steps for data capture (NS) and the number of measurements per step (ρ) are the parameters that were modified to study their effect on obtained electrical parameters in RED. NS of 10, 50, and 100 and ρ of 10 and 20 were used with this purpose. The accuracy of resulting current and voltage steps can be enhanced by increasing NS and ρ values, and according to obtained results, the higher accuracy of resulting output current and voltage steps, with low uncertainty of the average output steps (AOS) inside the operational region of power curve, was obtained using a DCS of NS = 100 and ρ = 20. The developed DCELM is a low-cost alternative to commercial electronic load devices, and the proposed methodology in this study represents an adaptative and optimizable CC mode characterization of RED process. The results obtained in this study suggest that data capture conditions have a direct influence of RED performance, and the accuracy of electrical parameters can be improved by optimizing the DCS parameters, according to the required specifications and the scale of RED prototypes.

Experimentation of MPPT Control Driving a Buck Converter with PV Module Disturbances and Variable Load in a Nanogrid

The objective of this paper is to perform a laboratory test on the performance of MPPT control in a nanogrid. The components used for tests are described, namely (i) a PV module SPP031001200 manufactured by Victron energy, a prototype of a synchronous buck converter controlled by Arduino Atmel ATmega V-2560, and a DC electronic load programmable 72-13210 manufactured by TENMATM. Among several MPPT controls, the choice falls on the methods Perturb and Observe “P&O” and Increment of the conductance “INC” which are more widely used than others. Laboratory tests with different PV module conditions and variable output voltage were performed. In full sunlight, the input power of the buck converter gives a better result with the INC method compared to the P&O method. For a PV module exposed to horizontal or vertical total shading, INC method gives a small advantage compared to the P&O method, which can be beneficial for a long time. Compared to the P&O method, INC method always gives better results due to its more complex algorithm. Due to the lack of measuring instruments, the different tests were performed without considering irradiance and temperature.

Research on DC Electronic Load System Based on PSO-PID Algorithm

At present, the control part of the DC electronic load is mainly based on analog control, that is, the control loop is controlled by an operational amplifier. Therefore, it is easy to cause slow response speed and overshoot in the process of current rise, and the improvement of response speed is of great significance to the test link. Therefore, this paper studies the digital control of DC electronic load. The DC electronic load control system has the characteristics of nonlinearity, and it is difficult to complete the theoretical modeling. Therefore, the MATLAB system identification toolbox is used to obtain the mathematical model. The traditional PID tuning method has a long time and poor effect. This paper adopts a parameter self-tuning PID controller based on particle swarm optimization algorithm. Through MATLAB simulation, the traditional PID control and particle swarm optimization PID control are simulated and compared. The results show that the digital controller has faster response speed and smaller overshoot than the conventional controller, and the system performance is significantly improved.

Interface Evolution of Solid Oxide Cells between the Electrode and the Interconnect Rib Induced with Applied Current

Herein, the interface evolution of solid oxide cells (SOCs) on the interfacial contact resistance (ICR) between the electrode and the interconnect rib at different current densities is quantitatively studied using a stainless steel 430 (SUS430)/(La,Sr) (Co,Fe)O3 (LSCF)/SUS430 sandwich structure. To simulate the actual operation of SOCs, different current densities (200, 400, 600, 800, and 1000 mA cm−2) are applied to the sandwich structure by an external power supply and a DC electronic load. Experimental results show that, under an isothermal condition for 1012 h and a thermal cycling condition for 15 times, ICR is smaller when the current density is increased. This phenomenon may be due to the softening of the oxide film on the SUS430 interconnect rib and an increase in the contact area between the SUS430 interconnect rib and the electrode LSCF. Additionally, the microstructure, surface roughness, and contact theory are analyzed in detail. The results indicate that interface contact between the electrode and the interconnect rib may be improved with suitable applied current. This work provides the understanding of possible interface evolution of SOCs induced with applied current.

Research on DC Electronic Load System Based on BP Neural Network PID Control

DC electronic load is a kind of instrument to replace the traditional dissipative resistance, which is widely used in the discharge performance test of DC power supply. However, it is difficult to achieve better control effect through analog circuit control in some test environments with high speed requirements for discharge test, and it is easy to produce overshoot. In digital circuits, however, in the actual control of DC electronic load, there are many uncertainties in the control system, such as interference and delay, which makes it difficult for the system to achieve the best control effect. This paper takes constant current mode as an example, in order to improve the effect of PID control, BP (Back Propagation) neural network is used to dynamically adjust the PID parameters online. After simulation analysis, under the ideal control environment, the adjustment time of BP-PID is only 0.0002s, which is 0.0005s higher than the traditional PID of 0.0007s. It can also reach a stable value within 0.0003s in the interference environment, with almost no overshoot. Therefore, compared with traditional PID control or analog circuit control, BP neural network PID control has better control effect on DC electronic load system.

Inductor Current Step Control with Input Voltage Feedforward for Fast Load Transient of Energy Recycling DC Electronic Load

Electronic load requires high input current slew rate for the dynamic test. An inductor current step (ICS) control (nonlinear control) cooperating with input voltage feedforward (linear control) during the transient is proposed to realize fast input current step response. The ICS control pushes the inductor current and the duty cycle to the target quiescent point within minimum time. Starting from the target quiescent point, the linear control with input voltage feedforward takes over. The advantage of proposed control is that the ICS control is able to break the low bandwidth in discontinuous conduction mode current loop, improving the input current slew rate. The input voltage feedforward can compensate the input capacitance current diversion, further improving the input current transient response. Compared with the conventional linear control, the maximum slew is increased from 32.9 to 699 A/ms, the settling time is decreased from 1.42 ms to 236 μ s, increased by 21.2 times and decreased by six times respectively, when the input current steps from 1 to 24 A at 200-V input voltage in a 5-kW prototype.

Wide Input Voltage DC Electronic Load Architecture With SiC MOSFETs for High Efficiency Energy Recycling

A SiC three-stage converter architecture of energy recycling dc electronic load with high frequency isolation is proposed. With interleaving boost converters and a LLC-DCX using 1200-V SiC MOSFETs as high frequency isolation pre-regulation stage, the proposed architecture can adapt to wide input voltage of 150-750 V with high efficiency. As the bus voltage is 780 V, a T-type three-level inverter is accepted as grid-connected stage for low leakage current, small grid current harmonics and high conversion efficiency. The transfer mechanism of second harmonic component of the input current ripple is analyzed and is well suppressed by proposed current program control. An overshoot-free soft-start control is proposed to minimize resonant current peak using the inverter reverse operation. The switching frequency reduction modulation control is proposed to solve the extremely low duty-cycle problem under high input voltage and low load condition. A seamless mode transition digital control of three-stage load is proposed with smoothly switched capability between the input current loop and input voltage loop to solve the duty-cycle mutation problem during mode transition. A 5-kW, 300-kHz SiC prototype with 150-750 V input was built. The peak full-load efficiency of three-stage architecture is 95% at 750 V input. The power density is 12.6 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> .

A Novel Two Stage Controller for a DC-DC Boost Converter to Harvest Maximum Energy from the PV Power Generation

In this article, an efficient and fast two-stage approach for controlling DC-DC boost converter using non linear sliding mode controller for a PV power plant is proposed. The control approach is based on two online methods instead of using the conventional combination of online and offline methods to harvest maximum energy and deliver an output PV voltage with reduced ripples. The proposed two-stage maximum power point tracking (MPPT) control can be integrated into many applications such as hybrid electric vehicles. Simulation results compared with the standard approaches P&amp;O prove the tracking efficiency of the proposed method under fast changing atmospheric conditions of an average 99.87% and a reduced average ripple of 0.06. The two-stage MPPT control was implemented involving the embedded dSPACE DSP in comparison to the classical P&amp;O to prove the efficiency and the validity of the control scheme. The experimental set-up system was carried out on boost converter and programmable DC electronic resistive load to highlights the robustness of the proposed controller against atmospheric changes and parametric variation.

Boundary Control With Corrected Second-Order Switching Surface for Buck Converters Connected to Capacitive Loads

Boundary control (BC) with second-order switching surface is exploited for achieving faster response time and robust operation of switching power converters. However, the system performance of the boundary-controlled converters is significantly affected when it is connected to a second-stage converter with a large input capacitor. This article studies the shortcomings in second-order BC schemes of buck converter with capacitive loads and nonlinear switching loads. Second, this article proposes a BC scheme with corrected second-order switching surface to drive buck converters cascaded to boost converters. The switching criteria of the corrected control law account for the effect of unknown load capacitance as well as the variation in filter parameters. Therefore, an outer voltage ripple feedback loop is introduced to determine the corresponding switching criteria gain factor that adjusts the overall gain, while maintaining the output voltage ripple at a specified voltage band. The proposed method is verified by both simulation and hardware experiments. A 250-W buck converter prototype has been built to validate the control scheme under different load types, including a resistive-capacitive load, a boost converter, and a commercial dc electronic load. A comparison is drawn between conventional BC and the proposed method in both simulation and experimental environment, in order to highlight the advantages of the proposed method. With this approach, the converter operates at designed BC parameters independent of load capacitance and system parameter variations.

Design of Program Control Interface of DC Charging Pile Verification Device

Design and manufacture a multi-function verification device for electric vehicle DC charging pile. This device is suitable for all levels of measurement department, charging pile Use Company and DC charger manufacturer. The accuracy of the DC charging pile verification device is 0.05, which is used for full-function verification before charging pile installation. It is mainly composed of high-precision standard electric energy meter, high-power program-controlled DC electronic load, main control unit and various functional modules. The DC charging pile verification device adopts the latest design technology and has stable and reliable performance.

Comprehensive approach for hybrid AC/DC distribution network planning using genetic algorithm

The neoteric AC/DC distribution networks are becoming more practical and cost-effective for several reasons such as high penetration of DC distributed generations (DGs) and also ever-increasing growth of sensitive DC electronic loads. Using these networks eliminates some required conversion stages which result in reduced costs and better power quality and reliability. This paper evaluates the economic efficiency of hybrid AC/DC distribution systems compared with conventional AC ones. For this purpose, a conceptual methodology for AC/DC distribution system planning is developed for making a fair comparison between AC and AC/DC distribution systems costs. The proposed methodology determines the optimal AC/DC distribution substation location and size and AC/DC feeder routing, as well as length and capacity of AC/DC feeders in both low-voltage and medium-voltage sides. The cost function comprises of investment and operational costs, including costs of construction, reliability, and loss. The proposed AC/DC planning approach is implemented in a region with no pre-assigned distribution system in different cases, and results are compared in both AC and AC/DC planning scenarios. Numerical results reveal that using hybrid AC/DC distribution systems in comparison with commonly used AC ones can lead to reduced total costs in the presence of sensitive loads and also high penetration of DGs.

A new approach for load flow calculation in AC/DC distribution networks considering the control strategies of different converters

Summary Utilization of AC/DC distribution networks has become more reasonable because of the recent developments in power electronic devices and increasing employment of DC electronic loads. In this paper, load flow calculation problem in AC/DC distribution networks is addressed. Because a large number of load buses in both AC and DC parts and high R/X ratios in the AC part of these networks can lead to the divergence of recent Jacobian matrix based methods, in this paper, a new direct approach based on backward forward sweep algorithm is presented. Comprehensive investigation considering weakly meshed and different types of converters and their control strategies is also carried out. The presented algorithm is applied to the test systems equipped with different types of converters. The results demonstrate the validity and capability of the proposed method.

Temperature Dependences on Various Types of Photovoltaic (PV) Panel

Temperature is one of the key roles in PV technology performance, since with the increases of temperature the open-circuit voltage will drop accordingly so do the electrical efficiency and power output generation. Different types of Photovoltaic (PV) panels- silicon solar panels and thin film solar panels; mono-crystalline, poly-crystalline, CIS, CIGS, CdTe, back-contact, and bi-facial solar panel under 40°C to 70°C approximately with 5°C interval have been comparatively analyzed their actual performances with uniformly distribution of light illumination from tungsten halogen light source, ±500W/m2. DC-Electronic Load and Data Logger devices with “Lab View” data program interface were used to collect all the necessary parameters in this study. Time needed to achieve a certain degree of temperature was recorded. Generally, each of the panels needed 15 minutes to 20 minutes to reach 70°C. Halogen based light source is not compatible in short wave-length in response to thin-film solar cell. Within this period of times, all the panels are facing a performance loss up to 15%. Other parameters; Pmax, Vmax, Imax, Voc, Isc, Rserries, Rshunt, Fillfactor were collected as study cases. Our study is important in determining Photovoltaic type selection and system design as for study or industrial needed under different temperature condition.

Constant Current Control of DC Electronic Load based on Boost Topology

DC electronic load has a relatively wide range of applications to test and evaluate the steady-state and transient response characteristics of emerging power sources. In this paper, a DC electronic load operating in constant current mode is presented. This device is designed based on Boost topology and can achieve high control accuracy. The experimental results show that the proposed electronic load has high precision and power scalability relative to the traditional resistive load. DOI: http://dx.doi.org/10.5755/j01.eee.20.2.6381

Design and Implementation of Intelligent Tester for LED Backlight LCD Display Driving Power

In accordance with the requirement of LED LCD driving power test and the basic principle of digital DC electronic load and combined with the trend of intelligentization, miniaturization, communication of electronic load, a new scheme of intelligent tester for LED LCD driver power based on PIC is proposed. It implements working modes of setting current, testing voltage, testing current, testing frequency, multi-channel transmission etc. Intelligent testing for ten states of LED LCD's four outputs under two power mode is supported. It can also send test data to upper computer for analysis with RS485 bus.

Fabrication of Membrane-Electrolyte Assembly with Nanocomposite for Direct Methanol Fuel Cell

This study aims to deal with the preparation of membrane-electrolyte assembly (MEA) of Pt/Ru/C nanocomposite as well as connecting to a direct methanol fuel cell and using PCB process packaging to test the efficiency of the DMFC. The components assembled in DMFC are including anode flow field plates, MEA and current collector.Using PCB boards for the anode flow field plates as well as the electicity collector plates and the type of flow field plate adopts serpentine flow field. For the efficiency of DMFC, liquid motors are used to press methanol mixed solution at specific temperature into DMFC. Besides, the cathode of DMFC adopts natural-breath method with air and uses DC electronic load to activate DMFC to investigate operating voltage and further to set constant voltage to measure current to calculate the efficiency of DMFC. Initial results of I-V curve show that self-developed MEA of Pt/Ru/C nanocomposite can enhance around 0.2% current density of DMFC after being assembled like commercial MEA

DC Load and Batteries Control Limitations for Photovoltaic Systems. Experimental Validation

This study first presents an experimental control strategy of photovoltaic (PV) system composed of: PV array, dc-dc power converters, electrolytic storage, and programmable dc electronic load. This control aims to extract maximum power from PV array and manages the power transfer through the dc load, respecting the available storage level. The designed system allows simultaneously the supply of a dc load and the charge or the discharge of the storage during the PV power production. The experimental results obtained with a dSPACE 1103 controller board show that the PV stand-alone system responds within certain limits that appear as soon as one of the storage thresholds is reached: either loss of energy produced, or insufficient energy toward the load. In urban area, it is proposed to overcome these limitations by connecting the utility grid with the PV system while maintaining the priority for self-feeding. The experimental results of this PV semi-isolated system are shown and discussed. For this first approach, the goal was to verify the technical feasibility of the suggested system controls. The final results are energetically relevant.

Fast Acting Regenerative DC Electronic Load Based on a SEPIC Converter

A fast acting regenerative dc electronic load based on the single-ended primary inductor converter (SEPIC) converter has been implemented. A simple multiloop feedback control system has been design for the SEPIC converter to realize the main function of electronic load. Instead of discharging via resistive load, the output of the converter is connected to rechargeable batteries such that discharged energy can be saved for future use. Circuit implementation of the proposed scheme is presented and experimental results are included to demonstrate the effectiveness of the proposed design.

Investigation of SmBaCuCoO5+δ double-perovskite as cathode for proton-conducting solid oxide fuel cells

Abstract SmBaCuCoO5+δ, a double-perovskite oxide, was synthesized by the modified Pechini method and developed as cathode material for proton-conducting solid oxide fuel cells. The SmBaCuCoO5+δ powders calcined at 800 °C, show the double-perovskite structure in powder XRD pattern. SmBaCuCoO5+δ has a more suitable thermal expansion coefficient than SmBaCo2O5+δ for BaCe0.7Zr0.1Y0.2O3−δ electrolyte-based solid oxide fuel cells. The single cell was tested with humidified hydrogen (∼3% H2O) as the fuel and static air as the oxidant. The performance of the cell was characterized by DC Electronic Load and AC impedance spectroscopy. The peak power densities reached 355–86 mW cm−2 in the range of 700–550 °C and the interfacial polarization resistance decreased with increasing operation temperature, from 3.1 Ω cm2 at 550 °C to 0.22 Ω cm2 at 700 °C. The high power density and low polarization demonstrate that SmBaCuCoO5+δ is a potential candidate for proton-conducting solid oxide fuel cells.

Maximum power tracking for photovoltaic power system: Development and experimental comparison of two algorithms

This work presents an experimental comparison of two algorithms developed in order to maximize the output power from a photovoltaic (PV) system for the same given set of conditions. The maximum power point tracking (MPPT) methods proposed in this study are two extended algorithms: Perturb and Observe and Incremental Conductance. The numerical modelling of the PV system shows the MPPT interest and then the extended MPPT algorithms are highlighted. In this paper, a PV system based on a boost converter as MPPT device is considered. A programmable DC electronic load is fed by two identical PV systems in which the MPPT control converter algorithms are different. This experimental platform operates under the same conditions such as changing solar radiation and cell temperature. The experimental results obtained with a dSPACE controller board show the MPPT energy efficiency of the proposed algorithms.