Faced with environmental issues caused by fossil fuel burning in the industrial and transportation sectors, innovations towards cleaner solutions to replace the ever diminishing fossil fuels have been the focus of not only researchers but governments all around the world. The hybrid electric vehicle (HEV) technology is the result of the desire to have vehicles with a better fuel economy and lower tailpipe emissions to meet the requirements of environmental policies as well as to absorb the impact of rising fuel prices. The objectives are met by combining a conventional internal combustion engine (ICE) with one or more electric motors powered by a battery pack that can be charged using an on-board generator and the regenerative braking technology to power the transmission. The challenge is to develop an efficient energy management strategy (EMS) to satisfy the objectives while not having a reduced vehicle performance. In this paper, EMSs that are proposed and developed in the recent years are revisited and reviewed. Additionally, the Plug-in HEV is discussed in a new perspective from the EMS point of view. The through-the-road (TtR) HEV with in-wheel motors (IWM) is a fairly new concept in the HEV design that features less complicated configuration with reduced hardware requirements and lower cost. Recent research findings are evaluated throughout this paper leading to a hypothetical TtR HEV materialization. A thorough discussion is made encompassing the advantages and disadvantages of the concept, its performance compared to conventional HEVs and the way forward.

A review on hybrid electric vehicles architecture and energy management strategies

In this paper, a novel platform for the single phase switched-capacitor multilevel inverters (SCMLIs) is presented. It has several advantages over the classical topologies, such as an appropriate boosting property, higher efficiency, lower number of required dc voltage sources, and other accompanying components with less complexity and lower cost. The basic structure of the proposed converter is capable of making nine-level of the output voltage under different kinds of loading conditions. Hereby, by using the same two capacitors paralleled to a single dc source, a switched-capacitor (SC) cell is made that contributes to boosting the value of the input voltage. In this case, the balanced voltage of the capacitors can be precisely provided on the basis of the series–parallel technique and the redundant switching states. Afterward, to reach the higher number of output voltage levels, two suggested SC cells are connected to each other with a new extended configuration. Therefore, by the use of a reasonable number of required power electronic devices, and also by utilizing only two isolated dc voltage sources, which their magnitudes can be designed based on either symmetric or asymmetric types, a 17- and 49-level of the output voltage are obtained. Based on the proposed extended configuration, a new generalized version of SCMLIs is also derived. To confirm the precise performance of the proposed topologies, apart from the theoretical analysis and a complete comparison, several simulation and experimental results are also given.

A New Boost Switched-Capacitor Multilevel Converter With Reduced Circuit Devices

Multilevel inverters (MLIs) are being used in wide range of power electronic applications. These converters have attracted a lot of attention during recent years and exist in different topologies with similar basic concepts. This paper presents five main submodules (SMs) to be used as the basic structures of MLIs. The paper reviews the common MLI topologies from the structural point of view. The topologies are divided into the different SMs to show conventional MLI configurations and future topologies that can be created from the main SMs. A comparative study between different topologies is performed in detail. The MLIs are categorized and investigated with from different perspectives such as the number of components, the ability to create inherent negative voltage, working in regeneration mode and using single dc source.

A General Review of Multilevel Inverters Based on Main Submodules: Structural Point of View

A comprehensive review of the key technologies for pure electric vehicles

The world is witnessing a change-over from its present centralized generation to a future with greater share of distributed generation. Hybrid energy systems are inter-connected with wind power, photovoltaic power, fuel cell and micro-turbine generator to generate power to local load and connecting to grid/micro-grids that decrease the dependence on fossil fuels. The hybrid system is a better option for construction of modern electrical grids that includes economic, environmental and social benefits. An overview of different distributed generation technologies has been presented. This paper puts forward a comprehensive review of optimal sizing, energy management, operating and control strategies and integration of different renewable energy sources to constitute a hybrid system. The feasibility of the different controllers such as microcontroller, proportional integral controller, hysteresis controller and fuzzy controller are presented. The controller is a closed loop feedback mechanism used for power regulation which achieves zero steady state error and the output signal generated from the controller produces desired output response.

A review on hybrid renewable energy systems

In recent decades, factors such as the worldwide growing concern for pollution induced climate changes, increasingly stringent emission norms for vehicles and depleting petroleum resources coupled with volatility in their prices have motivated and accelerated development of sustainable and clean alternatives for transportation systems. Electrification of vehicular technology (EVT) is considered as a promising and sustainable alternative for future transportation systems. In evolution of EVT, instability of fuel price, fuel economy, range, performance and costs are the governing factors and prime concerns for researchers, auto manufacturers and customers. These factors are decided by the design of the electric propulsion system (EPS) for vehicular application and its suitable integration with various electrical and mechanical components. In this paper, a comparative overview of EVT along with a comprehensive analysis of EPS and a brief discussion on power flow control and management algorithms for EVT is presented. The paper also highlights the ongoing technological advancements and future challenges in the roadmap of EPS for the electrification of vehicular technology.

Electric propulsion system for electric vehicular technology: A review

In this study, a multiple-input non-isolated DC/DC converter topology is presented. The proposed multiple-input DC/DC converter is proficient for energy diversification from renewable and storage energy sources individually or simultaneously. It can be operated in buck, boost and buck–boost modes of operation with the capability of bidirectional power flow to achieve desired voltage level on either side. The development of small-signal modelling based on state-space averaging has been discussed. In addition, a power management control scheme for the proposed converter has also been presented. The proposed concept has been investigated through simulation using the MATLAB/Simulink environment and validated experimentally on a laboratory prototype using dSPACE 1103 real time digital controller.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-pel.2012.0309

Multiple-input DC/DC converter topology for hybrid energy system

The interest in development of newer topologies of multilevel inverter has been increasing rapidly in past few years. Recently introduced topologies achieve higher number of output voltage steps with reduced number of switches, DC voltage sources, voltage stress across switches and losses as compared with the conventional topologies. In this study, a new structure of symmetrical multilevel inverter is proposed. The proposed structure offers reduced number of controlled switches, power diodes and DC sources as compared with classical and recently proposed topologies in the literature. Reduction of switch count and DC voltage sources reduces the size, cost, complexity and enhances overall performance. Proposed topology is capable of producing 7, 9 and 11 levels of output voltage with seven switches only. Moreover, significant reduction in voltage stress across the switches can be achieved. A comparative analysis of proposed topology with the conventional topology and recently published topologies has been made in terms of controlled switches, power diodes, driver circuit requirement, DC voltage sources and blocking voltage. Multi-carrier pulse-width modulation strategy is adopted for generating the switching pulses. Simulation study of the proposed topology has been carried out using Matlab/Simulink and feasibility of topology has been validated experimentally.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2015.0037

Hybrid topology of symmetrical multilevel inverter using less number of devices

Low reliability is one of the major concerns of multilevel inverter due to the requirement of a large number of semiconductor devices as compared to two-level inverters. Thus, in this paper, a novel topology of multilevel inverter is proposed that can tolerate both open and short-circuit faults on its switches. The proposed topology also reduces dc sources and capacitors as compared to the conventional and recently proposed fault-tolerant topologies. Two types of solutions are provided in order to make the proposed topology fault tolerant; first provides a partial solution to fault, while the second provides a complete solution to fault. In addition, a novel switching strategy is proposed to reduce the amount of capacitor voltage ripples under normal and postfault conditions. Also, the proposed switching scheme offers an additional advantage of self-voltage balancing of its capacitor voltage both under normal as well as postfault conditions. To validate the proposed concepts, simulation and experimental analysis are carried out and different results are presented to show the viability of the proposed topology under normal operation, during fault and postfault conditions.

A Single-Phase Five-Level Inverter Topology With Switch Fault-Tolerance Capabilities

In this study, two new structures of single-phase hybrid multilevel inverter are proposed for both symmetrical and asymmetrical configurations that can be employed in drives and control of electrical machines and connection of renewable energy sources. The proposed configuration uses a less number of semiconductor devices and DC sources as compared with conventional and newly developed topologies which lead to a reduction in cost and installation area. The proposed topology poses a vital advantage of self-voltage balancing of its capacitor voltage regardless of load type, load dynamics and modulation index. Also, the proposed topology is expanded in a cascaded fashion which reduces the complexity and improves the performance significantly. A wide range of comparison is done with conventional and newly developed topologies to show the superior performance of proposed topologies regarding a total number of switches and DC sources. The multi-carrier pulse-width modulation strategy is adopted for generating switching pulses for respective switches. A laboratory prototype is developed for testing the performance of the proposed topology for 9-level and 17-level inverters.

https://ietresearch.onlinelibrary.wiley.com/doi/pdf/10.1049/iet-pel.2017.0401

Lalit Kumar

Papers

Electric propulsion system for electric vehicular technology: A review

Multiple-input DC/DC converter topology for hybrid energy system

Hybrid topology of symmetrical multilevel inverter using less number of devices

A Single-Phase Five-Level Inverter Topology With Switch Fault-Tolerance Capabilities

Single-phase multilevel inverter topologies with self-voltage balancing capabilities