This paper presents the design and performance evaluation of a Type-II compensator for a dual active bridge (DAB) DC-DC converter used in electric vehicle (EV) DC fast charging applications. The system is configured to operate at a nominal power of 50 kW with a high-frequency transformer operating at 20 kHz. A comprehensive, control-oriented, small-signal model of the DAB converter is considered to facilitate the compensator design. The Type-II compensator is designed using frequency-domain techniques targeting a crossover frequency of 1 kHz with a high phase margin for improved dynamic performance. The performance of the Type-II compensator is quantitatively compared with a conventional PI controller through Software-in-the-Loop (SIL) simulations executed on the OPAL-RT real-time platform. SIL results show that the Type-II compensator achieves faster rise time, reduced settling time (0.02s), improved phase margin (66°), and enhanced disturbance rejection capabilities compared to the PI controller. Furthermore, high-frequency noise attenuation is significantly better with the Type-II compensator due to its additional high-frequency pole. These results validate the superior dynamic and robust performance of the Type-II compensator in DAB converter control scenarios, making it a viable alternative for next-generation EV charging systems.

The Dual-Active Bridge (DAB) converter’s versatility and ability to support bidirectional power flow make it a highly suitable option for modern power systems, especially in electric vehicle (EV) charging infrastructure. This paper explores phase shift control strategies for regulating power flow in DAB converters, with a particular emphasis on Single-Phase Shift (SPS) and Dual-Phase Shift (DPS) modulation techniques. The theoretical principles of power transmission within a DAB converter are detailed, and closed-loop control under both SPS and DPS modulation is demonstrated with simulation results using PLECS software. To validate these simulations, the closed-loop controllers were implemented in a 1kVA, 200V/200V DAB converter prototype, where the average efficiencies for SPS and DPS modulation were recorded at 96.69% and 97.05%, respectively. The paper concludes with a comparative analysis of the two modulation techniques.

Dynamic Wireless Charging systems for electric vehicles offers a revolutionary approach to EV charging, enabling vehicles to charge while in motion and overcoming the limitations of stationary wireless charging. Despite their efficiency and convenience, dynamic wireless charging systems introduce complex security vulnerabilities that must be addressed to ensure system reliability and safety. This paper provides a comprehensive review of the cyber-physical security challenges associated with electric vehicle dynamic wireless charging systems, examining potential threats such as cyber attacks and physical tampering. It identifies specific vulnerabilities in communication protocols, hardware, and software, and discusses various mitigation strategies such as encryption and physical layer security enhancements. Furthermore, the paper highlights recent advancements in security technologies and outlines future research directions to enhance the resilience of dynamic wireless charging systems. By addressing these security challenges, stakeholders can foster a safer environment for the deployment of dynamic wireless charging, thereby promoting the broader adoption of electric vehicles and advancing sustainable transportation solutions.

Looking at how electric vehicle charging stations are using renewable and clean energy resources such as fuel cells, solar photovoltaic and energy storage systems to reduce the impact on the grid, it is important that these resources are managed optimally. Therefore, the energy management systems (EMS) play a significant role for charging stations. In this paper, we analyze the different strategies and types of energy management systems used for electric vehicle charging stations.

The modular multilevel converter (MMC) has emerged as a captivating multilevel converter topology for medium to high-power applications. Due to aging and chemical process, the impedance characteristics of the capacitor in the submodule (SM) changes. This can result in an increase of SM capacitor voltage ripple and unequal power distribution among the SMs in the arm. Furthermore, prolonged use of degraded capacitors could interrupt the normal operation of the MMC. Existing SM capacitor voltage balancing approaches for the MMC are based on an assumption that all SMs have equal capacitance and ignore the component degradation. Hence, there is a need for closed-loop balancing control techniques that use instantaneous monitoring of capacitor parameters to enhance the reliability of the MMC. This paper addresses this gap by introducing an energy-based balancing control of SM capacitors, which effectively balances and controls the energy distribution among the SMs in the arm under the capacitor degradation. For validation of the proposed control strategy, detailed simulation studies are carried out for half-bridge SM based MMC in PLECS software platform.

The pivotal features of low self-discharge, high energy density and long calendar life lead the Lithium-ion (Li-ion) batteries as being a mainstream energy storage source in electric vehicles (EVs). A meticulous estimation of the state of charge (SOC) is indispensable for ensuring safe and reliable operations in battery powered EVs. However, SOC estimation of Li-ion battery with high accuracy have become a major challenge in the automotive industry. To fulfill reliable operation in EVs, researchers have proposed numerous SOC estimators through model based or machine learning techniques. This paper presents an improved SOC estimation of Li-ion battery using random forest (RF) regression, which is robust and effective for controlling dynamic systems. To ensure good resilience and accuracy, a Gaussian filter is adopted at the final stage to minimize the variations in the SOC estimation. The proposed SOC estimator is verified on the experimental data of the Li-ion battery under Federal test driving schedules and different operating temperatures. Results show that the proposed SOC estimator displays sufficient accuracy and outperforms the traditional artificial intelligence based approaches.

A novel topology for hybrid wireless power transfer (HPT), which uses both capacitive and inductive action, for electric vehicle charging is proposed in this paper. A three leg inverter topology is used for HPT. Two legs of the inverter, switched at 85 kHz, are used for inductive wireless power transfer (IPT) and the third leg, switched at 1 MHz, is used for capacitive wireless power transfer (CPT). Mixed switching frequency operation of the converter, is the novelty in proposed topology. Series-series compensation is used for IPT and dual LC compensation is used in CPT. The effectiveness of the proposed topology is simulated for a power level of 1 kW. IPT contributes to twice the power transfer than that of CPT.

A two-stage battery charger in battery operated electric vehicles (BEVs) and plug-in-hybrid electric vehicles (PHEVs) with wide output voltage range of 100-500 V is most suitable for all vehicle architectures. Existing battery chargers have a different limited range of output voltages of 36-48 V, 72-150 V and 200-450 V is achieved by varying the output voltage of DC/DC converters keeping a fixed voltage at DC link. A universal charger, which can address this wide range of battery pack voltages is suitable for all vehicle architectures. The most feasible way to meet this requirement of wide output voltage range is to vary the voltage at DC link with a fixed conversion voltage ratio at DC/DC converter. In this paper, we propose the use of cascaded converter in power factor correction (PFC) converters to achieve the wide DC link voltages for battery chargers. The primary focus of the paper is on the analysis and operation of boost-cascaded by buck (BoCBB) converter. The control implementation presented in the paper achieves a high input power quality, wide DC link voltages with universal input voltage ranges of 85-265 V. It also provides the degree of control freedom to operate even if the VNm (output voltage to the peak of Input) <; 0.5. Simulations of the proposed converter with 1 kW power rating are carried out in PSIM 11.0 software and the results with wide DC link voltage of 150-400 V are presented in the paper.

The modular multilevel converters (MMCs) have emerged as one of the promising topologies for medium/high power applications. The aluminum electrolytic capacitors (AECs) are usually employed in the MMC as floating capacitors due to their high volumetric efficiency and low price. The AECs are reported as one of the most fragile components in the converter, which gradually deteriorates over the time due to vaporization of the electrolyte. As a result, its capacitance decreases and equivalent series resistance (ESR) increases with ageing, which can result in an increase of submodule (SM) capacitor voltage ripple, power loss and could damage the operation of the MMC with prolonged use of the aged capacitors. Therefore, health monitoring of SM capacitors is essential to enhance the reliability of the MMC by predictive maintenance. This paper presents a new health monitoring technique for SM capacitors in the MMC utilizing inherent SM capacitor voltage fluctuations. The capacitance is estimated by second-harmonic impedance, which is evaluated using the ripple in capacitor voltage and current. The proposed method utilizes the available measurement used for the converter control and can be easily implemented in the same converter controller. The proposed scheme is verified for five-level MMC through simulation results in PLECS software.

The modular multilevel converter (MMC) employing multilevel submodules (SMs) displeys a reduced footprint size, voltage ripple and an improved efficiency compared to standard SMs. Due to capacitor voltage fluctuations in the SMs of the MMC, circulating current (CC) flows among the phase-legs. These currents can affect the system efficiency and menace the safe operation of MMC. Therefore, an active closed-loop CC controller is imperative for reliable operation of the MMC. The classical methods exhibit an awful steady-state performance, limited harmonic filtering, instability during load variations and complexity in digital implementations. This paper introduces a pseudo-derivative-feedback (PDF) based CC suppression control of the MMC in synchronous dq-frame. The design and implementation of the PDF controller are presented and adapted to minimize the CC. The theoretical analysis and numerical results obtained through simulations in PLECS software platform for seven-level flying capacitor SM based three-phase MMC are presented to verify the advantages of the PDF-based CC control.

Electric Energy Storage Systems are pivotal for cleaner and sustainable development, applications ranging from transport electrification to electric power generation from renewable sources require some form of energy storage. Supercapacitors (SC) or Electric Double Layer Capacitors (EDLCs) with their remarkably long life cycles and high power handling capabilities have a growing presence in the energy storage market. With their complementary attributes compared to batteries, EDLCs provide a potent solution for hybrid electrical energy storage and even replace batteries in certain power applications. The lower energy density and a linear voltage-charge relation, limits the use of supercapacitors. In this paper a simple and efficient method to overcome these issues and increase the energy utilization of SCs and thereby downsizing the number of SCs required for an application has been presented with simulation and experimental results.

This paper proposes an induction motor drive scheme generating multilevel twenty-four sided voltage space vector structure using single DC source. The topology consists of basic units with DC-source fed main three-level flying-capacitor (FC) inverter cascaded with two low-voltage floating-capacitor fed H-Bridge cells (CHB). The generated space vector structure has six concentric 24-sided polygons. The CHBs are modular and independent in operation performing low voltage switched filtering action canceling dominant low-order harmonics generated by the main inverter. Linear modulation index as close to base speed is achieved with 24-sided structure. Single DC source based topology allows four quadrant operation of drive system simpler. Modulation scheme with minimum switching operation for FC inverter is verified. Simulation results under steady state and transient operations for V/f scheme are presented in the paper and validated through experiment.

In the development stage of electric vehicle drive, simulation plays a vital role. It's a powerful tool which allows the developer to investigate various control strategies and test hardware systems in harmless work environment. The software simulations platform does have constraints. In that the complex mathematical operations take longer time to solve and eventually increases the overall simulation time and cannot perform the real-time operation. This simulation further needs to be converted to the target processor's language, either assembly or C- language, which will operate in the drive system. However, if a real-time simulation environment could be comprehended, then the real processor used in the system could be incorporated in the simulation. This eventually will eliminate the chance of introducing error during code translation as well as reduce simulation time. Also, the target controller could be tested within the simulation before introducing it the actual system. This paper discuss a concept of controller-in-loop simulation, which can be used to simulate the entire system in real-time. A simple dynamic model of Permanent Magnet Synchronous Motor is simulated with MATLAB/Simulink as well as on a TMS320F28069 digital signal processor from Texas Instruments Inc. Comparative study of simulation results of both the platforms, demonstrate that although MATLAB/Simulink provides excellent GUI and functionality, it fails to performs real-time simulation which can be accomplished with controller-in-simulation.

Over the last two decades, motor drives comprising of power electronic converters and advanced electric machines have deeply penetrated into the transportation sector, where new technologies are explored, in order to electrify various modes of transportation systems. Electric transportation puts much greater demand on power electronics than conventional fossil fuel powered automobiles. In many cases (e.g., hybrid internal combustion/electric drive vehicles), optimized power electronics suites are essential. Significant advances in power electronics and motor drives have helped reduce the cost and improve the efficiency of electric vehicles (EVs). This paper reviews on evolution and advancements of permanent magnet synchronous motor (PMSM) drive systems for EVs. The paper also discusses on multiphase PMSMs and multi-motor drive systems which can be revolutionized for future electric transportation applications.

In the past decade wireless power transfer with the help of magnetic field has been most popular. Contactless capacitive power transfer (CPT) system is an alternate form of wireless power transfer that is currently gaining popularly. However, capacitive power transfer systems are predominantly utilized in low power and small air gap applications applications due to low efficiency and high voltage that are developed across the coupling interface. This paper proposes two modified converters that utilize capacitive coupling for wireless electric vehicle charging applications. The proposed topologies over come the limitations of the existing wireless capacitive systems making them usable for high power applications. The paper discuss CPT systems for small and large airgap EV charging employment. The working, design and analysis of the two converters are detailed in this paper. The characteristics of the two converters that make the proposed topologies for EV charging applications are discussed. Finally, a 1kW CPT system is designed for the proposed converters and the simulations obtained agree well with the theoretical values that are calculated.

The future of transportation is inevitably all-electric, and its driving forces are electric energy storage devices. This is particularly true for urban mass transit modes, such as trains, trams, buses, and public utility trucks. Ultracapacitors (UCs) are gaining popularity in transportation storage applications to supply peak power and power transient demands, especially in mass transit electrification. The inherent low open circuit voltage is overcome by connecting UCs in series to obtain the desired DC-bus voltage. However, variations in internal parameters of these devices can lead to unbalanced voltages across each UC cell during charge-discharge cycles, which negatively affects lifetime, energy storage efficiency, and safety of the UC bank. To overcome this issue, a suitable cell balancing (power management) circuitry is employed, which enhances the lifetime and performance of the overall UC bank. This paper reviews the concepts of various UC cell balancing methods and the associated power electronic converter modules. Comparison between the various techniques are presented and different balancing methods are grouped based on their principle of operation.

The use of renewable sources of energy to charge electric vehicle (EV) batteries have drawn tremendous interest at present. The need for charging of EVs at convenient locations such as residential areas and semi commercial locations such as office parking lots and shopping malls have generated great interest in the use of solar energy for charging of the EV batteries where there is space restrictions and the need to reduce the dependency on the grid while charging, which shifts the focus towards DC charging infrastructures. Among some of the feature requirements, high power density and efficiency are important requirements. In this paper, the traditional Z source inverter(ZSI) has been modified and modeled to design a single stage DC charging converter. It uses both solar power generated from the PV array and single phase AC grid power to supply a constant charging power for the EV battery. The component sizing and the modeled topology has been shown and simulated results presented.

It is fairly well-known in circuit theory that the product of magnetic coupling coefficient and system quality factor is the single most important figure of merit (FOM) for optimizing the design of series-series-compensated resonant inductive coupling coils. Coils with high value of FOM can operate efficiently under misalignment conditions, such as poor coupling systems. This would be the case in transit systems with on-road/in-motion charging systems using inductive power transfer (IPT). Archimedean spiral coils are widely used for stationary charging of electric vehicles (EVs). This is due to ease of manufacturing, lower material cost, symmetric coupling profile, ease of experimental characterization, and very well-known magnetic characteristics. In this paper, a comprehensive analysis of Archimedean spiral coil structure has been presented, with the aim of establishing key design parameters, leading to high FOM. Knowing the key parameters in order to adjust the coupling coefficient and system quality factor gives a designer abundant options to design coils that can handle misalignment, and at the same time, minimize losses. For this purpose, 2D analysis of a range of coils with difference geometric parameters have been performed. Finite element analysis (FEA) has been used to establish key coil design parameters, in order to obtain a high value of FOM. Results of this design and analytical work will lead to efficient IPT coil design methodologies, which in turn will lead to considerable cost and energy savings. Due to their scalable and modular nature, this work is also applicable to any lumped system specifically utilizing Archimedean spiral coils.

In this paper thorough analysis of Series-Parallel resonant inductive coupling (SPRIC) has been presented using two-port network theory. Characteristic of SPRIC has been derived and plotted against load variation and frequency variation in MATLAB. Concept of forced resonance and natural resonance has been discussed. Important expressions such as current transfer ratio, voltage transfer ratio, maximum efficiency etc. has been derived and presented. To study the circuit behavior of the SPRIC a prototype has been built in the lab. Experimental results along with simulation results has been presented to verify the derived expression and characteristics of series-parallel topology.

This paper presents an approach of DC level 1 charging of an electric vehicle (EV) or plug-in hybrid electric vehicle (PHEV) making use of standalone solar photovoltaic (PV) system. In this approach it is proposed to use the DC power generated by solar panels to directly charge EV traction battery pack using solar MPPT controller algorithm and CHAdeMO DC fast charging protocol. A supervisory control algorithm is developed to handle the standalone solar conditions. With the proposed solution, any EV users with CHAdeMO DC fast charging port can charge their vehicle. An example of commercially available EV `Nissan Leaf' is considered for explaining the solution with 1 kW solar PV system. An average daily commuter distance is considered along with the survey data of different demographic solar energy harvesting capability. Calculations are made to prove that this solution can charge EVs off-the-grid, hence zero running cost.

In this paper, a single stage highly efficient photovoltaic grid interconnected charging infrastructure has been designed for off-board DC charging for electric vehicles. This paper starts with the design of a single phase H-bridge quasi-z-source inverter (qZSI), component design and the pulse width modulation technique used. Then it discusses the control techniques used to control the power flow from the photovoltaic to the grid. The versatile qZSI topology has been used for the battery charging system using traditional controls to connect a 2 kW solar array to the AC grid. An EV battery charger has been then designed using the highly efficient full bridge DC-DC converter employing primary side Zero Voltage Switching (ZVS) using the LLC topology for a wide output voltage range. Finally, the simulated performances of the power flow have been shown with and without the EV battery charger.

This paper presents a novel DC-link voltage balancing algorithm for a 3-level DC/AC traction inverter drive. In this topology, two DC-link capacitor voltages and three-phase line currents are measured, to generate the control pulses for the traction inverter, based on space-vector pulse width modulation (SV-PWM) scheme. Depending on the states of the two DC-link capacitors, redundant voltage vector sequences are used, to keep the capacitor voltages within a particular tolerance level. Phase current directions are also taken into account, because below a certain power factor level, it affects the capacitor voltage balancing capability. Simulation and experimental results are presented in this paper for a 6.0 kW interior permanent magnet synchronous machine (IPMSM) used for the electric vehicle (EV) traction applications. Both the simulation and experimental results show required performance of the proposed system.

A modified DC-link voltage balancing scheme for a three-level neutral point clamped inverter (NPC) with an interior permanent magnet machine (IPMSM) is presented. It uses two DC-link voltage sensors to take care of the voltage differences, and keep it to a required tolerance level. Switching control strategy is developed using a space-vector pulse width modulation (SV-PWM) scheme. Number of switching per switching cycle is optimised to five and changes in control strategy, depending on two capacitor voltage differences are only allowed to take place at starting of each switching cycle. It helps to reduce the switching losses. Details simulation studies are carried out in Matlab/ Simulink platform and an experimental setup is developed using dspace® based real time emulator. Simulation and experimental results show effectiveness of the proposed system.

The main objective of this paper is to study and analyze the power supply stage of a series-series (SS) fixed-frequency inductive power transfer (IPT) system, in order to suggest effective soft switching techniques to improve its performance. Because of the characteristics of the system, zero voltage switching (ZVS) operation was used and three control strategies were compared: phase-shift (PS) control, asymmetrical duty cycle (ADC) control and optimal asymmetrical voltage cancellation (o AVC) control. The o AVC control is found to be more efficient for this application. Additionally, this paper presents an inductive power transfer transformer (IPTT) prototype that was built in the laboratory, which helped validate the theoretical analysis and simulation results with practical tests. The plots and circuit simulations were obtained from MATLAB and SIMULINK respectively.

The seven papers in this special section explore the deployment of electrification in transportation systems.

This paper presents a modified DC bus voltage balancing algorithm for a neutral-point clamped (NPC) three-level inverter based motor drives for permanent magnet synchronous machines (PMSM) used in electric vehicle applications. The topology used for DC bus voltage balancing is based on nearest three vectors (N3V) with a space vector pulse width modulation scheme (SV-PWM). In this scheme, the voltage space vectors are rearranged based on the four redundant small voltage vectors, to keep the two DC link capacitor voltages in their specific tolerance bands, even during fast transient conditions of the machine. This topology provides high stability and lower switching loss compared to the conventional N3V scheme. The performance of the proposed scheme is verified by simulation and hardware experimental tests.

In this paper, three different ac-dc converter circuits are compared that can be used as energy harvesting circuits from piezoelectric sources, like periodic mechanical vibration of piezo-material cantilever beam, and used to supply voltage to charge battery energy storage devices. The study in particular investigates the effect of introducing the third and fifth harmonics along with the fundamental input on the output voltage, current and power delivered to the load. The model used for the Li-ion battery cell is also included. The comparison is done on an even basis by all circuits being open looped and having the same input parameters and load characteristics, i.e., battery model, for each circuit. The simulations were conducted using PSIM software implementing the three different energy harvesting mechanism their circuitry. The average load voltage and current was observed and the power delivered also recorded and compared. Simulation results are presented that output voltage is within 3.5 and 4.2 V. The study facilitates in understanding the nature of voltage and current response to the different approaches to the ac-dc conversion circuitry and provides an insight on the regime to store this energy produced by piezoelectricity.

This paper investigates the performance of a two level and a three level inverter drives for a permanent magnet synchronous machine (PMSM) under different switching frequencies. The experiments were conducted via a real time based system called Opal-RT. The inverters were operated at 1 kHz and 5 kHz switching frequencies. The torque was varied between 2 N.m and 4 N.m at a constant speed of 800 rpm. However the torque ripples and the copper losses between the two inverter drives were similar and the copper losses were independant of the swicthing frequency. At 5 kHz inverter switching frequency the two level inverter performed better at 4 N.m with a total current harmonic distortion of 2.55% and a torque ripple of 10%. However overall the three level inverter had low voltage and current harmonic distortion which translates to lower iron losses. Swicthing at 5 kHz frequency showed to have lower overall harmonic distortion than at 1 kHz for both inverters. The greater the capcitor voltage error the more the torque ripples even though the machine registered lower current total harmonic distortion for the three level inverter.

For the last two decades, significant improvements in charging technologies have been made. Moreover, novel applications have been proposed and tested, obtaining important and promising results. Inductive charging for electric vehicles (EV) and hybrid electric vehicles (HEV) is one of them. Because of the positive impact that this technology represents, it is important to understand the general characteristics of this novel application. This paper aims to give a general understanding of inductive charging systems for EV and plug-in HEV. The explanation of what is an inductive power transfer (IPT) transformer and how electrical power is transferred through air is also presented. The review of the electrical characteristics of an IPT transformer is shown: derivation of equations and presentation of the equivalent circuit. The analysis of the series-series (SS) compensation topology is covered. Additionally, to validate the theoretical concepts, an IPT transformer setup with a 5cm air gap is simulated. The simulation results where as expected from the theory. The power transfer capability of the system was increased from 0.05 W, with no capacitive compensation, to 87.6 W, with capacitive compensation. The plots and circuit simulations where obtained in MATLAB and SIMULINK respectively.

This paper studies different magnetization process of low cost permanent magnets used for permanent magnet synchronous machines (PMSM). Due to the limited resource availability of the rare earth materials, it is required to have an alternate solution for magnets used for permanent magnet machines. The type of magnet should be readily available and low cost. This paper gives a thorough review of the existing low cost magnets, those are generally being use in the PMSM machine and their control using power electronics converters.

This paper presents a modified stator flux estimation based direct torque control drive of a permanent magnet synchronous machine (PMSM) used in an hybrid electrical vehicle. It provides satisfactory transient and steady state performance of machine torque and speed over a wide speed variation. This utilizes a modified stator flux estimation scheme where a phase and magnitude compensator has been introduced at the output of low pass filter to compensate the error; this error keeps on changing with machine operating frequency. Detail simulation studies are carried out to verify the results in Matlab simulink platform.

Power electronic converters are playing an ever increasingly important role in today's electric vehicles. These regulated power electronic converters act as Constant Power Loads (CPLs) to the converters driving them. A CPL has a negative input impedance which results in a destabilising effect on closed-loop converters driving them. The use of power electronics in More Electric Vehicles (MEVs) is discussed, along with the CPLs they present and how they are modeled. Negative impedance instability is then discussed and the stability of various DC-DC converter topologies when loaded by CPLs is analyzed in both voltage-mode and current-mode control operating in Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM). Finally, the currently proposed control strategies that can stabilize a power electronic converter are discussed.