With the development of technologies in recent decades and the imposition of international standards to reduce greenhouse gas emissions, car manufacturers have turned their attention to new technologies related to electric/hybrid vehicles and electric fuel cell vehicles. This paper focuses on electric fuel cell vehicles, which optimally combine the fuel cell system with hybrid energy storage systems, represented by batteries and ultracapacitors, to meet the dynamic power demand required by the electric motor and auxiliary systems. This paper compares the latest proposed topologies for fuel cell electric vehicles and reveals the new technologies and DC/DC converters involved to generate up-to-date information for researchers and developers interested in this specialized field. From a software point of view, the latest energy management strategies are analyzed and compared with the reference strategies, taking into account performance indicators such as energy efficiency, hydrogen consumption and degradation of the subsystems involved, which is the main challenge for car developers. The advantages and disadvantages of three types of strategies (rule-based strategies, optimization-based strategies and learning-based strategies) are discussed. Thus, future software developers can focus on new control algorithms in the area of artificial intelligence developed to meet the challenges posed by new technologies for autonomous vehicles.

Fuel Cell Electric Vehicles—A Brief Review of Current Topologies and Energy Management Strategies

The usage of electric vehicles (EV) has been increasing over the last few years due to a rise in fossil fuel prices and the rate of increasing carbon dioxide (CO2) emissions. EV-charging stations are powered by existing utility power grid systems, increasing the stress on the utility grid and the load demand at the distribution side. DC grid-based EV charging is more efficient than AC distribution because of its higher reliability, power conversion efficiency, simple interfacing with renewable energy sources (RESs), and integration of energy storage units (ESU). RES-generated power storage in local ESU is an alternative solution for managing the utility grid demand. In addition, to maintain the EV charging demand at the microgrid levels, energy management and control strategies must carefully power the EV battery charging unit. In addition, charging stations require dedicated converter topologies, control strategies, and need to follow set levels and standards. Based on EV, ESU, and RES accessibility, different types of microgrid architecture and control strategies are used to ensure optimum operation at the EV-charging point. Based on the above said merits, this review paper presents different RES-connected architecture and control strategies used in EV-charging stations. It highlights the importance of different charging station architectures with current power converter topologies proposed in the literature. In addition, a comparison of microgrid-based charging station architecture with its energy management, control strategies, and charging converter controls are also presented. The different levels and types of charging stations used for EV charging, in addition to controls and connectors used, are also discussed. An experiment-based energy management strategy was developed to control power flow among the available sources and charging terminals for the effective utilization of generated renewable power. The main motive of the EMS and its control is to maximize the usage of RES consumption. This review also provides the challenges and opportunities in EV-charging, and parameters in selecting appropriate charging stations.

Electric Vehicles Charging Stations’ Architectures, Criteria, Power Converters, and Control Strategies in Microgrids

In this paper, a new high efficiency soft-switching non-isolated three-port converter (TPC) is proposed. In the conventional TPC, three switches are required to process power in different directions between inputs and output. Providing soft-switching condition for all switches using a low number of auxiliary components is a challenging task. In this paper, the conventional TPC topology is modified by changing its structure and adding a simple auxiliary circuit such that all switches operate under soft-switching condition in all operating modes. To reduce the volume of the converter, the magnetic components are integrated using a coupled inductor in the auxiliary soft-switching cell. In this paper, various converter operating modes are presented, and design considerations are discussed. Finally, a prototype 200 W, 100 V converter is implemented in the laboratory, and the theoretical analysis is validated by the experimental results.

/pdf/soft-switched-three-port-dc-dc-converter-with-simple-2r7dn7xh3g.pdf

Soft-Switched Three-Port DC-DC Converter With Simple Auxiliary Circuit

This article presents a high-gain DC-to-DC converter with a single switch, called the cubic converter, which provides very high voltage gain compared to the existing topologies such as the quadratic converter and conventional boost converter. The operation of the proposed converter at a lower duty ratio ensures lesser conduction losses. Various mathematical approaches are employed to confirm the higher voltage gain and improved efficiency of the converter. The proposed cubic boost converter (CBC) is compared with the quadratic boost converter (QBC) and other converters discussed in the literature. A generalized nth-order boost converter is also derived. To test the effectiveness of the QBC and CBC circuits, the Hardware-In-the-Loop (HIL) validation is performed using Typhoon HIL 402 real-time emulator machine. Moreover, the proposed topology is tested and compared with other topologies for maximum power point tracking (MPPT) of a solar photovoltaic (PV) array to show its effectiveness in a real-world scenario. A detailed comparison between conventional boost, QBC and CBC is presented for dynamic partial shading conditions in real-time mode using Typhoon HIL 402 real-time emulator machine.

/pdf/performance-analysis-and-hardware-in-the-loop-hil-validation-6knfqjgi6h.pdf

Performance Analysis and Hardware-in-the-Loop (HIL) Validation of Single Switch High Voltage Gain DC-DC Converters for MPP Tracking in Solar PV System

With the rapid development of modern energy applications such as renewable energy, PV systems, electric vehicles, and smart grids, DC-DC converters have become the key component to meet strict industrial demands. More advanced converters are effective in minimizing switching losses and providing an efficient energy conversion; nonetheless, the main challenge is to provide a single converter that has all the required features to deliver efficient energy for different types of modern energy systems and energy storage system integrations. This paper reviews multilevel, bidirectional, and resonant converters with respect to their constructions, classifications, merits, demerits, combined topologies, applications, and challenges; practical recommendations were also made to deliver clear ideas of the recent challenges and limited capabilities of these three converters to guide society on improving and providing a new, efficient, and economic converter that meets the strict demands of modern energy system integrations. The needs of other industrial applications, as well as the number of used elements for size and weight reduction, were also considered to achieve a power circuit that can effectively address the identified limitations. In brief, integrated bidirectional resonant DC-DC converters and multilevel inverters are expected to be well suited and highly demanded in various applications in the near future. Due to their highlighted merits, more studies are necessary for achieving a perfect level of reducing losses and components.

A Review on State-of-the-Art Power Converters: Bidirectional, Resonant, Multilevel Converters and Their Derivatives

The solar PV based power generation systems are growing faster due to the depletion of fossil fuels and environmental concerns Combining PV panels and energy buffers such as battery through multi-port converter is one of the viable solutions to deal with the intermittency of PV power The goal of this paper is to design and analyze the proposed triple port DC-DC buck-boost converter for high step-up/step-down applications It has two unidirectional ports (port-1 and port-3) and one bi-directional port (port-2) for harnessing photovoltaic energy and charging the battery At port-1, the combined structure of buck and buck-boost converter is used with a particular arrangement of switches and inductors The step-up/step-down voltage conversion ratio is higher than the conventional buck-boost converter, and the polarity of the output voltage is maintained positive The battery is added at the bi-directional port, for the storage of energy through the bi-directional boost converter The switches operate synchronously for most of the modes making the control strategy simple The characteristics and modes of operation along with a switching strategy, are elaborated Experimental results are presented which validate the agreement with the developed theoretical expectation

/pdf/non-isolated-high-gain-triple-port-dc-dc-buck-boost-518e15sph5.pdf

Non-Isolated High-Gain Triple Port DC–DC Buck-Boost Converter With Positive Output Voltage for Photovoltaic Applications

A nonisolated three-port DC–DC converter based on Cuk topology (NI-TPC) to handle the renewable sources (RS) is proposed in this paper. This converter includes two unidirectional input ports accommodating both a fuel cell (FC) and photovoltaic (PV) cell; and one output port with DC load. Due to the inductors at all the ports, it claims the advantage of continuous input and output currents. Additionally, it uses less number of switches, diodes and inductors compared with conventional ‘n-1’ separate Cuk converters. Synthesis procedure for a generalized n-port DC–DC structure is explained. The derivation law based on conventional Cuk converter, operating principle, design calculation, and analysis are presented in detail, and then the analysis is validated through simulation and a 100W prototype, verifying the performance of the proposed NI-TPC converter.

https://www.mdpi.com/2079-9292/8/2/214/pdf

Chellammal Nallaperumal

Papers

Non-Isolated High-Gain Triple Port DC–DC Buck-Boost Converter With Positive Output Voltage for Photovoltaic Applications

A Nonisolated Three-Port DC–DC Converter with Continuous Input and Output Currents Based on Cuk Topology for PV/Fuel Cell Applications