Isolated Wired and Wireless Battery Charger with Integrated Boost Converter for PHEV and EV Applications

Vehicle charging and vehicle traction drive components can be integrated for multi-functional operations, as these functions are currently operating independently. While the vehicle is parked, the hardware that is available from the traction drive can be used for charging. The only exception to this would be the dynamic vehicle-charging concept on roadways. WPT can be viewed as a revolutionary step in PEV charging because it fits the paradigm of vehicle to infrastructure (V2I) wirelessly. WPT charging is convenient and flexible not only because it has no cables and connectors that are necessary, but due more to the fact that charging becomes fully independent. This is possibly the most convenient attribute of WPT as PEV charging can be fully autonomous and may eventually eclipse conductive charging. This technology also provides an opportunity to develop an integrated charger technology that will allow for both wired and wireless charging methods. Also the integrated approach allows for higher charging power while reducing the weight and volume of the charger components in the vehicle. The main objective of this work is to design, develop, and demonstrate integrated wired and wireless chargers with boost functionality for traction drive to provide flexibility to the EV customers

Review of Electric Vehicle Charging Technologies, Configurations, and Architectures

Electric Vehicles (EVs) are projected to be one of the major contributors to energy transition in the global transportation due to their rapid expansion. The EVs will play a vital role in achieving a sustainable transportation system by reducing fossil fuel dependency and greenhouse gas (GHG) emissions. However, high level of EVs integration into the distribution grid has introduced many challenges for the power grid operation, safety, and network planning due to the increase in load demand, power quality impacts and power losses. An increasing fleet of electric mobility requires the advanced charging systems to enhance charging efficiency and utility grid support. Innovative EV charging technologies are obtaining much attention in recent research studies aimed at strengthening EV adoption while providing ancillary services. Therefore, analysis of the status of EV charging technologies is significant to accelerate EV adoption with advanced control strategies to discover a remedial solution for negative grid impacts, enhance desired charging efficiency and grid support. This paper presents a comprehensive review of the current deployment of EV charging systems, international standards, charging configurations, EV battery technologies, architecture of EV charging stations, and emerging technical challenges. The charging systems require a dedicated converter topology, a control strategy and international standards for charging and grid interconnection to ensure optimum operation and enhance grid support. An overview of different charging systems in terms of onboard and off-board chargers, AC-DC and DC-DC converter topologies, and AC and DC-based charging station architectures are evaluated

DESIGNING METHOD FOR INTEGRATED BATTERY CHARGERS IN ELECTRICAL VEHICLES

Electrical vehicles often make use of multi-phase induction motors. At the same time, the vehicles have an on-board charger, the power electronics device that converts the ac power from the mains and charges the traction battery. The traction inverter can be integrated with the charger, reducing in this way the component count, weight and cost, while the windings of the ac motor can be used as the inductors required to complete the charger topology, thus saving on passive components, iron and copper. The integrated charger performances depend on the configuration of the stator windings as well as on the topology of the power converter. The objective in charging mode is reaching a high efficiency while keeping the charging-mode electromagnetic torque at zero. In traction mode, the goals include the efficiency and the torque-per-Amps ratio. In order to compare and distinguish between the available topologies and configurations, the paper starts with the analysis of the magnetic field in the air-gap of the electric machine in both charging and traction modes. Based upon that, a novel algorithm is proposed which determines the space-time distribution of the air-gap field, eventually deriving all the relevant pulsating and revolving component of the magnetic field, thus providing the grounds for studying the losses, efficiency and torque pulsations in both charging and traction modes

A ripple reduction method for a two stages battery charger with multi-winding transformer using notch filter

This paper presents a two-stage battery charger consisting of a bridgeless Totem-pole power factor correction (TP-PFC) circuit and a full bridge converter with a multi-winding transformer. By using this transformer the cell equalizing operation can be achieved with no additional circuitry. In addition, a double-line frequency ripple reduction method is proposed to address the low frequency current ripples issues existing in both primary and secondary winding of the transformer which is caused by the voltage ripples across the intermediate DC link bus. Control and analysis of the converter at different operation modes is illustrated in detail and simulation results validate the effectiveness of the proposed converter and control algorithm

Interim results of the H2020 project FITGEN: design and integration of an e-axle for the third-generation electric vehicles

The aim of the European H2020 project FITGEN is to develop a functionally integrated e-axle, demonstrated on a full electric urban vehicle platform, fit for implementation in the third-generationelectric vehicles. The e-axle features a 6-phase synchronous internal permanent magnet electric motor driven by a Silicon-Carbide inverter, coupled with a high-speed transmission and complemented by a DC/DC converter for both high voltage operation of the electric motor as well as for superfast charging. Preliminary results shows that the adoption of formed litz wire in the stator allow for a filling factor exceeding 50%, and that the design of the motor is capable of peak performance of 135 kW / 170 Nm, achieving at maximum operational speed of 22,500 rpm and a gravimetric power density of 5.2 kW/kg (i.e. above 50% compared to the 2018 industry standard). This paper presents the interim results of the project with an in-focus look at the end-user requirements, vehicle integration, development of the inverter-motor, optimisation of the cooling system group and integration of the on-board charger

New SR drive with integrated charging capacity for plug-in hybrid electric vehicles (PHEVs)

Plug-in hybrid electric vehicles (PHEVs) provide much promise in reducing greenhouse gas emissions and, thus, are a focal point of research and development. Existing on-board charging capacity is effective but requires the use of several power conversion devices and power converters, which reduce reliability and cost efficiency. This paper presents a novel three-phase switched reluctance (SR) motor drive with integrated charging functions (including internal combustion engine and grid charging). The electrical energy flow within the drivetrain is controlled by a power electronic converter with less power switching devices and magnetic devices. It allows the desired energy conversion between the engine generator, the battery, and the SR motor under different operation modes. Battery-charging techniques are developed to operate under both motor-driving mode and standstill-charging mode. During the magnetization mode, the machine's phase windings are energized by the dc-link voltage. The power converter and the machine phase windings are controlled with a three-phase relay to enable the use of the ac-dc rectifier. The power converter can work as a buck-boost-type or a buck-type dc-dc converter for charging the battery. Simulation results in MATLAB/Simulink and experiments on a 3-kW SR motor validate the effectiveness of the proposed technologies, which may have significant economic implications and improve the PHEVs' market acceptance

An Integrated On-Board Battery Charger with a Nine-Phase PM Machine

A fully integrated on-board battery charger for electrical vehicles (EVs) has been developed recently using a nine-phase machine. All the components used for propulsion are employed in the charging process, no additional components are required, and there is no need for hardware reconfiguration between charging and propulsion modes of operation. The proposed solution can be connected directly to single-phase or three-phase grid to perform charging, so that the expensive off-board charger infrastructure is not needed. The only requirement is to use a nine-phase machine in combination with a nine-phase inverter in the powertrain of the EV. This however inevitably brings in further advantages in the propulsion mode, such as increased fault tolerance and the current subdivision into more phases. The benefits of the topology, originally developed for an induction machine, make it interesting for further investigation. Therefore, the performance of the charger is examined here using a permanent magnet synchronous machine (PMSM). The results show that the charger topology is applicable to other types of synchronous machines and is, even more importantly, independent of the angular spatial shift between the individual three-phase windings of the nine-phase machine’s stator. The results are comparable with those obtained using an induction machine and confirm the viability of the solution in conjunction with the PMSM as a propulsion motor

Efficiency Evaluation of Fully Integrated On-board EV Battery Chargers with Nine-Phase Machines

A fully integrated on-board battery charger for future electric vehicles (EVs) has been recently introduced. It re-utilizes all the propulsion components of an EV in charging/vehicle-to-grid (V2G) modes, it does not require any additional components or hardware reconfiguration, and charging/V2G modes are realized with zero electromagnetic torque production. Both fast (three-phase) and slow (single-phase) charging are possible, with unity power factor operation at the grid side. The solution is based on the use of a triple three-phase machine and a nine-phase inverter/rectifier. This paper reports on the results of efficiency evaluation for the said system. Testing is performed using both a nine-phase induction machine and a nine-phase permanent magnet (PM) machine for a range of operating conditions in charging/V2G modes, with both three-phase and single-phase grid connection. Additionally, the impact of converter interleaving on the losses and efficiency is also studied. Losses are separated for different subsystems, thus providing an insight into the importance of optimization of different EV power train components from the efficiency point of view. Promising efficiencies, in the order of 90%, are achieved although none of the system components have been optimized