Bidirectional DC-DC Converter Research Articles

A New Continuous Input Current Nonisolated Bidirectional Interleaved Buck-Boost DC-DC Converter

In this paper, a new interleaved bidirectional buck-boost DC-DC converter is proposed. The input current of this converter is continuous and has a low ripple, that cause reduction in the size of the input filter of the converter. Because of these features, this converter is appropriate for renewable applications such as fuel cells and photovoltaic (PV) panels for obtaining maximum power in which the continuity of the input current is essential. The operation principle of this converter is detailed, and its power losses calculation shows the positive effects of the low input current ripple on its efficiency. The input current ripple of the proposed converter and conventional interleaved buck-boost converter has been calculated in detail. In addition, the comparison results of this converter with conventional interleaved buck-boost converters and other similar structures confirm that the proposed converter without utilizing extra components achieves continuous input current with low ripple. Compared with other buck-boost structures, the low input current ripple in the presented converter causes an improvement in its efficiency. An experimental prototype is implemented in the laboratory to confirm the correctness of theoretical analyses.

DC-DC Converter Implementing Soft Switching Technique for AC Power Applications

Global warming alerts the world to switch over to using Electric Vehicle (EV) and Hybrid Electric Vehicles (HEV). The Bidirectional DC-DC Converter (BDC) plays a significant role in controlling the energy flow for the Battery Ultra-capacitor Energy Storage System (BUESS) which is used for storing energy in EV or HEV. The bidirectional DC-DC converter (BDC) plays a vital role in controlling the energy flow for BUESS. The bidirectional DC-DC converter performs the step-up and step-down operation at zero voltage switching, as it operates in buck and boost modes. Due to the uncertain nature of renewable energy resources they pose to be not suitable for standalone applications as the only source of power. This problem can be overcome with the aid of batteries and supercapacitors for storing energy. Fast charging is done by a supercapacitor and slow discharging by a battery. A hysteresis control loop achieves the design of charging and discharging status. A BDC in addition to an inverter can be opted and is implemented in MATLAB/Simulink, and is used in AC power applications.

Golden Eagle Optimized Control for a Dual Stage Photovoltaic Residential System with Electric Vehicle Charging Capability

ABSTRACT In this article, the control of a grid-connected, single-phase, dual-stage photovoltaic (PV) residential system with electric vehicle (EV)-charging capability is being presented. A residential system faces a lot of dynamic conditions such as changing atmospheric condition or random patterns of load connection or disconnection as well as power failure. In this regard, this article proposes the optimization of proportional and integral gains selection of the bidirectional DC/DC converter (BDC) PI controller through golden eagle optimization (GEO) algorithm to improve the system performance. The system is subjected to various induced dynamic conditions simulated in MATLAB Simulink environment and the performance is compared with particle swarm optimization, genetic algorithm, and gains obtained through hit and trial. In comparison with other techniques, GEO algorithm provides optimum BDC PI gains, as a result, the DC-link voltage achieves 1.5 times shorter settling time. During the non-linear load changes and voltage swell condition, the settling time is 2 times shorter. Settling time of the EV battery power shows 1.7 times reduction. The transient response of the PV power also shows dramatic improvement with 3 times faster settling time during solar insolation changes. During the sudden non-linear load changes, the momentary transients die 1.5 times faster. Moreover, a seamless control is developed to achieve a seamless transition from islanded mode to grid connected mode and vice versa. The proposed system achieves unity power factor and complies with the IEEE -519 power quality standard.

An autonomous flexible power management for hybrid AC/DC microgrid with multiple subgrids under the asymmetric AC side faults

In this paper, an autonomous flexible power management is proposed for hybrid AC/DC microgrid with multiple subgrids under the asymmetric AC side faults. First, based on the double-frequency disturbance of the DC common bus (DCB) voltage caused by asymmetric AC side faults, this paper analyzes the characteristics of the transmission power of bi-directional DC/DC converters (BDCs) and bi-directional AC/DC converters (BACs) adopt the normalized droop control (NDC). Then, interactive relationships between DCB voltage and DC subgrids bus voltage, AC subgrids bus frequency are derived. According the interactive relationships, suppression links combined with virtual component adjustment coefficients are designed for BDCs and BACs to eliminated the double-frequency disturbance of the transmission power. Meanwhile, the support links is added to the power control of BACs to maintain the frequency automatically once the energy storage (ES) in faulty AC subgrid becomes unavailable due to the line protection. Furthermore, with the autonomous flexible power management, the total load demand proportionally shared among the remaining subgrids can be accordingly attained when faulty AC subgrid or its local ES quit the operation. Finally, the system stability analysis is given and the results of Hardware-In-Loop tests verify the correctness and effectiveness of the proposed autonomous flexible power management.

RETRACTED: Control of Bidirectional DC-DC Converter for Micro-Energy Grid’s DC Feeders' Power Flow Application

Referred to by: Retraction notice to ‘Control of Bidirectional DC-DC Converter for Micro-Energy Grid’s DC Feeders' Power Flow Application' IJRED 11(2), 533-546International Journal of Renewable Energy Development, 12(6). https://doi.org/10.14710/ijred.2023.57139

Fault-Tolerant Operation of a Multimode Stacked Switch Rectifier Leg Through Built-In Circuit Redundancy

In this paper, the open-circuit fault-tolerant operation of a multi-mode stacked switch rectifier leg is presented and investigated. A fault-tolerant control technique is proposed through the built-in circuit redundancy operation of the presented multi-mode stacked switch rectifier leg. A bidirectional CLLC resonant DC-DC converter that employs the presented leg is used to demonstrate the features of the presented control scheme. The proposed control is able to allow post fault operation of the converter to continue to deliver the demanded load power with soft-switching operation in case any switch experiences an open-circuit fault. In addition, the built-in circuit redundancy of the leg allows the resonant converter to operate in different operating modes, resulting in an enhanced control in regulating the output voltage while avoiding the switching frequency to diverge far from the resonant frequency, leading to better performance and improved efficiency with the complete soft-switching operation before and after the fault. To highlight the merits of the proposed fault-tolerant control in the multi-mode stacked switch rectifier leg, experimental results are provided on a 300W resonant converter prototype with an input of 250V and an output voltage of 400V.

Control of BLDC motor and Regenerative Braking in Electric Vehicle

Abstract: With the rising economy, fuel demand also increases. In today's world, fossil fuels are the major contribution to meeting these demands. However, it is not going to be the same scenario in the next decades as the fossil fuels levels are depleting there is a need for an alternative fuel that will satisfy energy requirements and will be a sustainable source in coming years. In the automotive industry petrol and diesel have been major fuels in driving vehicles. Although electric vehicles are going to be replaced by IC engines. Electric vehicles have lower fuel costs as compared to internal combustion engines but because of limited charging stations vehicles are bound to drive within certain distances. With the implementation of regenerative braking in electric vehicles, it is possible to charge batteries when the vehicle is breaking and thus increasing driving distance. This paper presents a simulation of control of BLDC motor with regenerative braking. Keywords: Regenerative Braking, BLDC Motor, Bi-Directional DC-DC Converter, VSI, Electric Drives.

Design and Control of an Off Board Battery Charger for Electric Vehicles

The rise in the penetration of electric vehicles has led to the increased interest in the charging technologies. Controlled charging and vehicle to grid power transfer is being given much importance. This paper proposes an off board charger (three phase) for charging the batteries used in electric vehicles. The proposed charger has a bidirectional power transfer capability so as to transfer power back to the utility grid. The topology proposed is simple and less costly as it has fewer elements. The charger has two converters, a three phase ac-dc converter for conversion of ac into dc and bidirectional dc-dc converter. The technique called Vector control is used to control ac-dc converter which allows controlling of active and reactive power independently. The control strategy proposed here provides a better control and leads to a better performance while maintaining unity power factor at input. The charging algorithm designed is such that it is able to maintain voltage at dc link at desired value. The charging algorithm is designed for lithium ion batteries and the combined Constant Current Constant Voltage (CC-CV) method of charging is used because it is simple and easy to implement. The proposed electric vehicle charger changes the mode of charging with change in State of Charge (SOC). The different modes are switched and the suitable reference is generated based on the different charging characteristics of a battery. The proposed charger is modeled in MATLAB-Simulink. The working operation of both forward and reverse power transfer mode has been analyzed. The proposed charger is able to maintain the unity power factor operation. The simulation results of all modes validate the design and control of the proposed charging topology.

Modeling, Analysis, Design, and Simulation of a Bidirectional DC-DC Converter with Integrated Snow Removal Functionality for Solar PV Electric Vehicle Charger Applications

Different factors affect solar photovoltaic (PV) systems by decreasing input energy and reducing the conversion efficiency of the system. One of these factors is the effect of snow cover on PV panels, a subject lacking sufficient academic research. This paper reviews and compares current research for snow removal in solar PV modules. Additionally, this paper presents the design, analysis and modelling of a smart heating system for solar PV Electric Vehicle (EV) charging applications. The system is based on a bidirectional DC-DC converter that redirects the grid/EV-battery power into heating of the solar PV modules, thus removing snow cover, as well as providing the function of MPPT when required to charge the EV battery pack. A control scheme for each mode of operation was designed. Subsequently, a performance evaluation by simulating the system under various conditions is presented validating the usefulness of the proposed converter to be used in solar PV systems under extreme winter conditions.

Bidirectional DC-DC Converter for Electric Vehicle

The present work aims at designing and modelling of a bidirectional DC DC converter for driving a Permanent Magnet DC (PMDC) motor for Hybrid Electric Vehicle (HEV) and Electric Bikes (EV) application. Permanent Magnet Brushed DC (PMBDC) motors and Permanent Magnet Brushless DC (PMBLDC) motors are the most popular options that are used for the integration of an electric bicycle and bikes. But despite of the simple controllers and low cost of the PMDC motor its lower efficiency sets it back in choice in the present scenario as compared to the BLDC motors. The present design aims at improving the efficiency of the PMDC motor traction drive system by the incorporation of the bidirectional DC DC converter between the electrical source and the traction motor which in addition to its primary function of providing the traction energy, also facilitates the energy regeneration during braking (in the case of HEV and EV) and during the motion along down the slope(in case of a pedalled electric bicycle).

An efficient online energy distribution management system based on predictive control

An efficient online energy-distribution management system (EMS) that ensures cells operate under optimized conditions, is critical for the high performance and long-term service of large energy storage or generation systems. In this work, a novel two-level structure EMS based on model predictive control (MPC) is proposed to achieve fast energy balance with high-efficiency. The topology of the EMS is that cells are divided into several modules and each module connected in parallel with a bi-directional DC-DC converter, where the outputs of DC-DC converters are serially connected to obtain a higher DC bus voltage. Then the issues of energy deviations among cells are resolved by a two-level structure EMS which consists of an energy-distributing intra-group balance layer and a cell package current-distributing inter-group balance layer. Based on the EMS topology, an MPC is employed in each module to improve the balance speed while maintaining the stability of the DC-DC converter output voltage. Moreover, the parameters of the controller are optimized via simulation study. Finally, the EMS performance is validated by a hardware-in-loop platform and compared with existing EMS. The experimental results show that the proposed EMS can realize quick and accurate energy balance with low energy loss.

Power Electronics Converters for the Internet of Energy: A Review

This paper presents a comprehensive review of multi-port power electronics converters used for application in AC, DC, or hybrid distribution systems in an Internet of Energy scenario. In particular, multi-port solid-state transformer (SST) topologies have been addressed and classified according to their isolation capabilities and their conversion stages configurations. Non-conventional configurations have been considered. A comparison of the most relevant features and design specifications between popular topologies has been provided through a comprehensive and effective table. Potential benefits of SSTs in distribution applications have been highlighted even with reference to a network active nodes usage. This review also highlights standards and technical regulations in force for connecting SSTs to the electrical distribution system. Finally, two case studies of multi-port topologies have been presented and discussed. The first one is an isolated multi-port bidirectional dual active bridge DC-DC converter useful in fast-charging applications. The second case of study deals with a three-port AC-AC multi-level power converter in H-Bridge configuration able to replicate a network active node and capable of routing and controlling energy under different operating conditions.

A Battery Management Strategy in a Lead-Acid and Lithium-Ion Hybrid Battery Energy Storage System for Conventional Transport Vehicles

Conventional vehicles, having internal combustion engines, use lead-acid batteries (LABs) for starting, lighting, and ignition purposes. However, because of new additional features (i.e., enhanced electronics and start/stop functionalities) in these vehicles, LABs undergo deep discharges due to frequent engine cranking, which in turn affect their lifespan. Therefore, this research study seeks to improve LABs’ performance in terms of meeting the required vehicle cold cranking current (CCC) and long lifespan. The performance improvement is achieved by hybridizing a lead-acid with a lithium-ion battery at a pack level using a fully active topology approach. This topology approach connects the individual energy storage systems to their bidirectional DC-DC converter for ease of control. Besides, a battery management strategy based on fuzzy logic and a triple-loop proportional-integral (PI) controller is implemented for these conversion systems to ensure effective current sharing between lead-acid and lithium-ion batteries. A fuzzy logic controller provides a percentage reference current needed from the battery and regulates the batteries’ state-of-charge (SoC) within the desired limits. A triple-loop controller monitors and limits the hybridized system’s current sharing and voltage within the required range during cycling. The hybridized system is developed and validated using Matlab/Simulink. The battery packs are developed using the battery manufacturers’ data sheets. The results of the research, compared with a single LAB, show that by controlling the current flow and maintaining the SoC within the desired limits, the hybrid energy storage system can meet the desired vehicle cold cranking current at a reduced weight. Furthermore, the lead-acid battery lifespan based on a fatigue cycle-model is improved from two years to 8.5 years, thus improving its performance in terms of long lifespan.

Energy management system for a small-scale microgrid

In recent years, the power system has been evolved into microgrids, which are little pockets of self-contained entities. Different distributed, interconnected generation units, loads, and energy storage units make up a typical microgrid system. The increased energy efficiency of these units on microgrids is gaining popularity day by day. Because of their stochastic behavior, renewable generation causes an imbalance in the power system, which needs microgrid energy management. To solve these issues, a variety of novel approaches have been explored in the literature. For the stand-alone microgrid in this research, efficient energy management and control mechanism is adopted. A photovoltaic system, a wind turbine, and a battery energy storage device make up this stand-alone microgrid. The power stability of the hybrid system is ensured by a sophisticated controller. The main purpose of this study is to regulate the DC/DC bidirectional converter (DBC), which connects the Li-ion battery to the DC bus of the stand-alone microgrid. This paper describes the development of a wind/photovoltaic power generation system to the load, as well as MPPT techniques like perturb and observe (P&O). The system is simulated and the results are presented using MPPT techniques. There is no requirement for a specific power model in the suggested method. Only power and voltage system data are used by DBC. A stand-alone microgrid system was simulated using MATLAB.

The state-of-the-art of power electronics converters configurations in electric vehicle technologies

Today, the Internal Combustion Engine (ICE) is gradually being replaced by electric motors, which results in higher efficiency and low emission of greenhouse gases. The electric vehicle either works wholly or partially on electrical energy generated from batteries and ultra-capacitors. The battery or ultra-capacitor is either charged from the AC supply connected to a grid line in a plug-in electric vehicle or from ICE in a hybrid electric vehicle. Alternatively, the battery charges from the traction motor by regenerative braking. In the reverse direction, the energy from the battery or ultra-capacitor is injected into the AC grid line in the plug-in electric vehicle. Power electronic converters play a vital role in the conversion process from grid line to traction motor and in the reverse direction. In this paper, the role of power electronics converters in an electric vehicle is elaborated. The bidirectional DC-DC converter plays a vital role in the power conversion process of electric vehicles. The existing bidirectional DC-DC converter topologies are discussed with a comprehensive review, comparison, and application. Additionally, the advancement in power electronics converters to improve the efficiency and reliability of the vehicular system is elaborated.

Hybrid Renewable Power Generation for Modeling and Controlling the Battery Storage Photovoltaic System

A major portion of the global energy demand was likely to be fulfilled by an extensive supply of renewable power. Renewable energy outputs, on the other hand, are changeable due to the dynamic nature of their sources. The integration of these variable sources of power into current power grids is proving difficult for electrical power system operators all around the world. The fundamental issue with renewable energy systems is that, due to the stochastic nature of renewable power, electricity production varies from period to period. Recent research and development on renewable technologies can ensure the islands’ long-term electricity supply. Renewable energy sources, on the other hand, are limited by their unpredictable nature and significant reliance on weather conditions. To offset this disadvantage, several renewable energy sources and converters must be joined. To balance the power generation and load power, a hybrid renewable power generation for standalone application is proposed. The solar plant model is made up of a 170 W photovoltaic (PV) panel connected in series, and conversion of energy is done using the maximum power point tracking (MPPT) algorithm, which regulates a buck-boost converter modulation. The MPPT method used in the converter’s control step is based on perturb and observe (P&O) and enhanced with a PI controller. The bidirectional buck-boost DC-DC converters (BBDC) are utilized to preserve a DC-link voltage stable. This is also storing additional hybrid energy in a large battery and is distributed to the system load; then there is a shortage of hybrid power. The load current power is regulated in terms of the frequency and enables it to be achieved using three vector control technique voltage source inverters (VSI). The results were offered to demonstrate a hybrid performance of this organization.

Control Strategy for Bidirectional DC-DC Converter Based on Cascade Connection of LC Filter and DAB Converter

Control Strategy for Bidirectional DC-DC Converter Based on Cascade Connection of LC Filter and DAB Converter

Current Source Mode Bidirectional DC/DC Converter With Multiple-Level Output Conversion Ratios Based on the Hybrid PWM Control of the Switched-Capacitor Structure

The current source (CS) mode bidirectional dc/dc converter (Bi-DCC) with multiple-level output current ratios is presented. Using the hybrid pulsewidth modulation (PWM) method to control the conversion selection mechanism realizes the multiple-level conversion options in both bidirectional energy flows. It is suitable for future all-electrical driving and braking systems in electric vehicles, supplying power to adjust the motor dynamics control during vehicle driving and collecting the energy generated during braking, especially on different road conditions. Moreover, the function that one single converter provides multiple-level conversion ratios, makes the design highly suitable for smart manufacturing as it can simplify the design by type and configuration variations. This design mainly focuses on dealing with applications directly powered by the CS, for example, the connection of photovoltaic (PV) units, CS mode motor controller, current-based power systems, and CS mode light-emitting diodes. A 300 W prototype with a conversion selection structure (CSS), which contains three switching orders and ten levels of current options, has been established. It validated multiple conversion ratio selections for step-down and step-up operation modes, high stability, and low power cost through the simulation and experiment results.

Modeling and control of a solar-thermal dish-stirling coupled PMDC generator and battery based DC microgrid in the framework of the ENERGY NEXUS

In this paper a control scheme and power management technique for solar-thermal dish-Stirling and battery based islanded DC microgrid system has been developed for the nexus of energy. This paper has used the solar-thermal dish-Stirling with battery storage in an islanded microgrid for charging purpose of battery for the first time which is also feeding the variable load. The PMDC generator provides the energy in steady state and transient time energy is fulfilled with connected battery storage. Here a charging strategy based on the PMDC generator output that alters with irradiance and temperature mostly and a battery integrated DC microgrid is developed. Unidirectional DC-DC converter is employed with solar-thermal dish-Stirling coupled PMDC generator and a bidirectional DC-DC converter connected to battery and DC grid with controller and power management strategy in varying state of charge and irradiance. A Matlab model of microgrid structure is implemented to check the feasibility along with dynamic load and irradiance.

Photovoltaic-Battery-Ultracapacitor-Diesel Hybrid Generation System for Mobile Hospital Energy Supply

This paper deals with the energy management of a hybrid power system, which consists of a photovoltaic (PV) system, diesel generators, battery, and ultracapacitor for a mobile hospital. The proposed power system can supply energy to shelter hospitals for better treatment of patients in remote states, particularly in the event of a pandemic situation such as Coronavirus Disease 2019 (COVID-19). For this reason, a hybrid power system in which a diesel generator is used with a photovoltaic energy source for reliable availability of power supply. Moreover, battery and ultracapacitor are also integrated to obtain a hybrid power generation and storage system to ensure the smooth operation of mobile hospitals irrespective of weather conditions. A boost converter is used with PV panels to operate them in either maximum power tracking mode or power curtailment mode. The battery is connected to a bidirectional reversible DC-DC converter for direct-current (DC) bus voltage regulation and state of charge control. The ultracapacitor is associated with the battery to compensate for the peak power. The diesel generator is connected in parallel with the photovoltaic generator, battery, and ultracapacitor to continuously provide the power required by the load. The integrated operation of all generation sources and storage systems is complex for shelter hospitals. Therefore, an efficient energy management algorithm is developed to manage the continuous energy flow between different elements of the hybrid power system and mobile hospital load through the control of the power converters. Finally, validation results are presented to show the effectiveness of the proposed energy management algorithm for the hybrid power system.