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

Model predictive control power management strategies for HEVs: A review

A family of nonisolated high-voltage-gain dc–dc power electronic converters is proposed. The suggested topologies can be used as multiport converters and draw continuous current from two input sources. They can also draw continuous current from a single source in an interleaved manner. This versatility makes them appealing in renewable applications such as solar farms. The proposed converters can easily achieve a gain of 20 while benefiting from a continuous input current. Such a converter can individually link a PV panel to a 400-V dc bus. The design and component selection procedures are presented. A 400-W prototype of the proposed converter with $V_{\text{in}} = 20$ and $V_{\text{out}} = 400$ V has been developed to validate the analytical results.

A DC–DC Converter With High Voltage Gain and Two Input Boost Stages

A new nonisolated multiinput multioutput dc-dc boost converter is proposed in this paper. This converter is applicable in hybridizing alternative energy sources in electric vehicles. In fact, by hybridization of energy sources, advantages of different sources are achievable. In this converter, the loads power can be flexibly distributed between input sources. Also, charging or discharging of energy storages by other input sources can be controlled properly. The proposed converter has several outputs with different voltage levels which makes it suitable for interfacing to multilevel inverters. Using of a multilevel inverter leads to reduction of voltage harmonics which, consequently, reduces torque ripple of electric motor in electric vehicles. Also, electric vehicles which using dc motor have at least two different dc voltage levels, one for ventilation system and cabin lightening and other for supplying electric motor. The proposed converter has just one inductor. Depending on charging and discharging states of the energy storage system (ESS), two different power operation modes are defined for the converter. In order to design the converter control system, small-signal model for each operation mode is extracted. The validity of the proposed converter and its control performance are verified by simulation and experimental results for different operation conditions.

A Nonisolated Multiinput Multioutput DC–DC Boost Converter for Electric Vehicle Applications

In the last two decades, emerging use of renewable and distributed energy sources in electricity grid has created new challenges for the utility regarding the power quality, voltage stabilization and efficient energy utilization. Power electronic converters are extensively utilized to interface the emerging energy systems (without and with energy storage) and smart buildings with the transmission and distribution systems. Flexible ac transmission systems (FACTSs) and voltage-source converters, with smart dynamic controllers, are emerging as a stabilization and power filtering equipment to improve the power quality. Also, distributed FACTSs play an important role in improving the power factor, energy utilization, enhancing the power quality, and ensuring efficient energy utilization and energy management in smart grids with renewable energy sources. This paper presents a literature survey of FACTS technology tools and applications for power quality and efficient renewable energy system utilization.

Review of FACTS technologies and applications for power quality in smart grids with renewable energy systems

Cost of various energy storage technologies is decreasing rapidly and the integration of these technologies into the power grid is becoming a reality with the advent of smart grid. Dynamic voltage restorer (DVR) is one product that can provide improved voltage sag and swell compensation with energy storage integration. Ultracapacitors (UCAP) have low-energy density and high-power density ideal characteristics for compensation of voltage sags and voltage swells, which are both events that require high power for short spans of time. The novel contribution of this paper lies in the integration of rechargeable UCAP-based energy storage into the DVR topology. With this integration, the UCAP-DVR system will have active power capability and will be able to independently compensate temporary voltage sags and swells without relying on the grid to compensate for faults on the grid like in the past. UCAP is integrated into dc-link of the DVR through a bidirectional dc–dc converter, which helps in providing a stiff dc-link voltage, and the integrated UCAP-DVR system helps in compensating temporary voltage sags and voltage swells, which last from 3 s to 1 min. Complexities involved in the design and control of both the dc–ac inverter and the dc–dc converter are discussed. The simulation model of the overall system is developed and compared to the experimental hardware setup.

https://ieeexplore.ieee.org/ielaam/5165391/7063283/7063313-aam.pdf

An Integrated Dynamic Voltage Restorer-Ultracapacitor Design for Improving Power Quality of the Distribution Grid

Penetration of various types of distributed energy resources (DERs) like solar, wind, and plug-in hybrid electric vehicles (PHEVs) onto the distribution grid is on the rise. There is a corresponding increase in power quality problems and intermittencies on the distribution grid. In order to reduce the intermittencies and improve the power quality of the distribution grid, an ultracapacitor (UCAP) integrated power conditioner is proposed in this paper. UCAP integration gives the power conditioner active power capability, which is useful in tackling the grid intermittencies and in improving the voltage sag and swell compensation. UCAPs have low energy density, high-power density, and fast charge/discharge rates, which are all ideal characteristics for meeting high-power low-energy events like grid intermittencies, sags/swells. In this paper, UCAP is integrated into dc-link of the power conditioner through a bidirectional dc-dc converter that helps in providing a stiff dc-link voltage. The integration helps in providing active/reactive power support, intermittency smoothing, and sag/swell compensation. Design and control of both the dc-ac inverters and the dc-dc converter are discussed. The simulation model of the overall system is developed and compared with the experimental hardware setup.

An Ultracapacitor Integrated Power Conditioner for Intermittency Smoothing and Improving Power Quality of Distribution Grid

A control scheme for a distributed Inverter Molecule™ architecture is analyzed and implemented in this paper. An Inverter Molecule is a building block for a novel distributed inverter architecture suitable for PV/Battery applications which exceeds the performance metrics obtained by Central/String- inverters with or without DC/DC optimizers or by Micro-Inverters. The proposed transformerless architecture utilizes low-voltage semiconductor devices with much higher yields than their high-voltage counterparts. A group of Inverter Molecules operate autonomously and cooperatively to maintain the grid interconnection requirements while providing maximum power control on each molecule's PV panel. This paper overviews the state-of the-art control methods implemented mostly on cascaded H-bridge derived topologies and further establishes a distributed control scheme for Inverter Molecule architecture that does not need any high bandwidth communications except a heartbeat signal at line frequency. Experimental results are presented for a lab-scaled prototype.

Design and implementation of distributed control architecture of an AC-stacked PV inverter

Grid integration of distributed energy resources (DERs) is increasing rapidly. Furthermore, smart grid technologies are making the grid more bi-directional providing opportunities to consumers to supply power back to the grid. Energy storage technologies like battery and ultracapacitor (UCAP) can be integrated through grid-tied inverters to support variable DERs such as solar and wind. In these cases, the energy storage with active power capability can improve grid performance by providing active and reactive power support. In this paper, the concept of providing active/reactive power support and renewable intermittency smoothing to the distribution grid by UCAPs is presented. UCAPs have a higher number of charge-discharge cycles and higher terminal voltage per module when compared to batteries which make them ideal for providing grid support. The UCAP is integrated into the dc-link of the active power filter (APF) through a dc-dc converter. The dc-dc converter provides a stiff dc-link voltage which improves the performance of the grid tied-inverter. Design and control of both the dc-ac inverter and the dc-dc converter are very important in this regard and presented. The simulation model of the overall system is developed and results are compared to the results from an experimental hardware setup.

An Integrated Active Power Filter–Ultracapacitor Design to Provide Intermittency Smoothing and Reactive Power Support to the Distribution Grid

Multi-input converters are becoming important in various renewable energy applications like wind energy, fuel cell systems, photovoltaic systems, and hybrid electric vehicles. In this paper, it is shown that in a double-input buck converter the dead-time of the switch commands along with the two duty ratios will have a direct impact on the amount of current drawn from the sources/inputs. This dead-time is used as an additional control variable apart from the switch commands to meet the control objective of meeting a constant load demand when the source currents are varying which is very common in hybrid energy systems. Theoretical derivations agree well with the simulation results. The new control method has good dynamic response and improves the speed of the system.

Deepak Somayajula

Papers

An Integrated Dynamic Voltage Restorer-Ultracapacitor Design for Improving Power Quality of the Distribution Grid

An Ultracapacitor Integrated Power Conditioner for Intermittency Smoothing and Improving Power Quality of Distribution Grid

Design and implementation of distributed control architecture of an AC-stacked PV inverter

An Integrated Active Power Filter–Ultracapacitor Design to Provide Intermittency Smoothing and Reactive Power Support to the Distribution Grid

Power sharing in a double-input buck converter using dead-time control