Non-pulsating Input Current Research Articles

Control Scheme for a Quadratic-Based Step-Down On-Board DC/DC Converter to Be Used in Hybrid Electric Vehicles

This paper discusses a switching regulator with a quadratic-based step-down DC/DC converter designed using a reduced redundant power processing principle. This converter benefits from a non-complex topology, which aims to process energy more efficiently. The switching regulator can be used on-board in hybrid electric vehicles and has a non-pulsating input current, which is suitable to process energy from lithium-ion batteries. Design expressions and steady-state operating conditions are given for the converter. Models are obtained to design and implement a two-loop controller. The simplicity of this approach is of significant value in a method of design-oriented analysis, in which the analytic results can be used to make design choices. Loop-shaping techniques are used to design a robust controller to regulate the output voltage of the proposed converter under voltage variations on the lithium-ion batteries and the changes in load current requirements, as well as parameter uncertainties of the converter. The design conditions for the gains of the controller are derived. The models of the converter are verified through experimental results for a 300 W prototype and used to design a robust controller. Finally, closed-loop time and frequency domain tests are given to show the performance of the switching regulator.

Nonisolated DC–DC Power Converter Synthesis Using Low-Entropy Equations

There is a growing demand for novel nonisolated dc–dc power converters with the deployment of dc power distribution systems integrating renewable sources and energy storing elements. The load and source of these applications have different input and output voltage levels, and it is vital to avoid operating the interfacing power converters at extreme duty ratios. Therefore, engineers and researchers explore the power converter synthesizing techniques since the mid-1970s, fulfilling the above requirement besides the nonpulsating input and output current. Among them, the analytical synthesis method has gained popularity, although it gives rise to high-entropy equations. This article shows a simple yet powerful topology synthesis method based on the low-entropy equations that reveal the connection between the energy storing elements and switches. To this end, a set of design rules have been introduced in this article to realize the voltage-second balance equations obtained by decomposing the voltage gain polynomial using design-oriented analysis. Moreover, different decomposition levels of the gain polynomial have been discussed to embed inductors at either input or output or both ports. Furthermore, the synthesis of multitopology converters using low-entropy equations has been demonstrated. The applicability of the proposed method is validated using motivational examples and using experimental results of the selected converters.

Load-Independent Hybrid Resonant Converter for Automotive LED Driver Applications

In this article, a hybrid resonant LED driver for automotive illumination applications is proposed. The employed <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> resonant network provides load-independent output current characteristic and accomplishes full soft-switching operation of the semiconductor devices within the desired input voltage range. To provide constant frequency operation and nonpulsating input current, a continuous conduction mode boost structure is merged into the resonant network. Also, the analog dimming capability range of 50%–100% is attained for the LED string by adjusting the main switches operating duty cycle. Detailed theoretical analysis of the proposed LED driver is presented. To verify the analysis and effectiveness of the proposed topology, a 40-W laboratory prototype is designed and implemented for the input voltage range between 8–18 V.

High Step-Up Converter Based on Non-Series Energy Transfer Structure for Renewable Power Applications.

In this paper, a high step-up boost converter with a non-isolated configuration is proposed. This configuration has a quadratic voltage gain, suitable for processing energy from alternative sources. It consists of two boost converters, including a transfer capacitor connected in a non-series power transfer structure between input and output. High power efficiencies are achieved with this arrangement. Additionally, the converter has a common ground and non-pulsating input current. Design conditions and power efficiency analysis are developed. Bilinear and linear models are derived for control purposes. Experimental verification with a laboratory prototype of 500 W is provided. The proposed configuration and similar quadratic configurations are compared experimentally using the same number of components to demonstrate the power efficiency improvement. The resulting power efficiency of the prototype was above 95% at nominal load.

A Non-Pulsating Input Current Step-Up DC/DC Converter With Common Ground Structure for Photovoltaic Applications

Many of the High Gain Step-Up DC/DC converters proposed in the literature do not share common ground and have a pulsating or discontinuous input current, making the converter unsuitable for solar photovoltaic applications. In this article, a non-pulsating input current (NPIC) with a high-gain DC/DC step-up converter is proposed and analyzed in detail. The converter shares a common ground structure and a voltage conversion ratio more than twice that of the Traditional quadratic boost converter (TQBC). The converter has two switches that operate in phase, which makes it easy to control. Also, the voltage stress across all semiconductor devices is lower than the output voltage, which enhances the efficiency of the converter. The loss analysis is carried out with the PLECS software, integrating the real models of switches and diodes from the technical datasheet. To confirm and validate the functionality of the proposed converter, a 200 W hardware prototype is being developed in the laboratory. It was observed that the maximum efficiency was 94.5% with an input voltage of 16V. The converter achieves high gain at low duty cycles and has been shown to perform well in open loop conditions.

Analysis of bridgeless converter model for power factor correction

In this study, a novel single-stage bridgeless single-ended primary-inductor converter (SEPIC) model is designed to perform effective power factor correction while driving brushless direct current (BLDC) motors. The traditional SEPIC converter model produces a non-pulsating input current that operates with both conductors in a continuous-conduction mode(CCM). However, the proposed SEPIC converter is designed to function as an AC-DC converter; specifically, it is a cascade combination of the boost and buck-boost converters. Functionally, during discontinuous-condution mode (DCM), the boost converter becomes operational, whereas the buck-boost converter operates during the continuous-condution mode. Using the proposed SEPIC model, naturally the computed power factor is improved, which makes it employable for driving BLDC motors. During the implementation of the proposed model, the rotation of the permanent magnet BLDC motor was regulated through the continuous-conduction mode of operation of the bridgeless rectifier. On conducting both the simulation and hardware design process, comparisons were made based on the power factors obtained using the traditional buck-boost converters and those obtained using the SEPIC models presented herein. The SEPIC model proved its higher efficiency over the traditional converters from the viewpoint of the evaluated power factor values and minimized conduction losses. The newly modeled SEPIC model, which was designed for power factor correction, has been noted for its applicability in low power household applications. A power factor of 0.9 is obtained for the hardware implementation of the proposed converter, and a working model of the proposed converter is found to exhibit superior performance when compared with simulated models of the buck–boost converter and SEPIC.

Inherently Non-Pulsating Input Current DC-DC Converter for Battery Storage Systems

With an ever-growing number of batteries being integrated into the electric grid, bidirectional converters with non-pulsating dc input current are required to replace the existing bidirectional converters so as to extend the lifetime of such dc power suppliers. Bidirectional DC-DC converters are increasingly used in a variety of applications including uninterruptable power supplies, electric vehicles and renewable energy systems. In this study, we propose a new topology of bidirectional dc-dc converter with inherently non-pulsating input current (NPIC), which is intended to be used for battery energy storage systems. With simple modifications from the conventional converters, the proposed NPIC converter has no inherent pulsating input current in the step-down (buck) mode under both continuous and boundary conduction modes (CCM and BCM), whereas in the step-up (boost) mode, the proposed NPIC converter retains the desired voltage gain. Underpinning theories, operating principles and steady-state performances are analyzed and presented in detail, which are then corroborated by simulation and experimentation. The proposed converter topology, with simple design principle and ease for implementation, is likely to have wide-ranging applicability in interfacing electrochemically functioned dc sources to modern power systems.

PV based Agricultural Pumping System using Boost Inverter Fed Induction Motor

This paper presents a simple, cost-effective scheme for agricultural pumping system. It consists of PV array, canonical switching cell converter (CSCC), Boost inverter, and induction motor. The input power for the boost inverter is obtained from the photovoltaic (PV) based CSCC. The requirement of lower number of components and nonpulsating input current are the superior features of the CSC converter. The conversion of DC voltage obtained from the PV based CSC converter system into high voltage AC using the boost inverter is the main feature of the proposed scheme. Extraction of maximum power from the PV system is ensured in this paper by means of a P &amp; O MPPT algorithm. Because of a high step up CSC converter and boost inverter, this scheme requires fewer number of PV arrays to power the induction motor for pumping system. Effectiveness of the proposed scheme is verified through MATLAB/SIMULINK environment and necessary results are presented.

A High-Efficiency DC/DC Converter for High-Voltage-Gain, High-Current Applications

A new class of high-voltage-gain dc–dc converters for high-efficiency and transformer-less dc–dc applications, where large voltage step-up ratios are required, is presented in this paper. The converter is derived from the hybrid integration of a switched-capacitor converter and a boost converter. It features high step-up voltage conversion ratio with a moderate duty cycle, nonpulsating input current, low-voltage stress on all of the switches, easy implementation of control and driving circuits, scalability for high-current high-power applications, and low cost due to reduced components via combination of a two-stage converter into a single-stage converter. Full soft-charging operation and minimal device voltage stresses are achieved under all operating conditions. Steady-state operations of the converter are comprehensively analyzed. A 300-W prototype of a 19-time converter achieving the peak efficiency of 96.1% is built. Both simulation and experimental results validating the theoretical analysis and operation of the converter are provided.

Micro‐inverter based on single‐ended primary‐inductance converter topology with an active clamp power decoupling

The reliability and lifespan of micro-inverters are two significant features of AC-module photovoltaic systems. One of the most effective methods to enhance the reliability and life duration of micro-inverters is achieved by substituting their electrolytic power decoupling capacitor with the film capacitors. In this study, a new DC/AC inverter based on an isolated single-ended primary-inductance converter with an active clamp power decoupling is introduced. The proposed converter has no electrolytic capacitor which results in long lifetime and high reliability. Moreover, the inverter has simple structure and low number of semiconductor switches which improve the efficiency and make it cost effective. The sufficient stepping up ability for output voltage without increasing turns ratio excessively, non-pulsating input current, and appropriate isolation make the proposed micro-inverter a proper choice for grid-connected applications. The converter operating modes are discussed and design considerations are presented. Finally, experimental results of the implemented prototype validate aforementioned features and performance of the proposed micro-inverter.

A novel quadratic Boost converter with low current and voltage stress on power switch for fuel-cell system applications

This paper presents a novel quadratic Boost converter with good features: no abruptly changing on capacitors' voltage and inductors' current in the whole switching cycle which can assure no instantaneous overcurrent or overvoltage on storage elements, non-pulsating input current that can make the input filter design easier, low current and voltage stress on power switch. The basic operating principles and the mathematical model of this novel quadratic Boost converter are presented. The steady state and the small signal dynamical behaviors are analyzed and the comparisons among other quadratic Boost converters are described and concluded. Finally, the Pspice simulations and the corresponding circuit experiments are presented for confirmation.