This paper reviews the current status and implementation of battery chargers, charging power levels, and infrastructure for plug-in electric vehicles and hybrids. Charger systems are categorized into off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports battery energy injection back to the grid. Typical on-board chargers restrict power because of weight, space, and cost constraints. They can be integrated with the electric drive to avoid these problems. The availability of charging infrastructure reduces on-board energy storage requirements and costs. On-board charger systems can be conductive or inductive. An off-board charger can be designed for high charging rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3 (fast) power levels are discussed. Future aspects such as roadbed charging are presented. Various power level chargers and infrastructure configurations are presented, compared, and evaluated based on amount of power, charging time and location, cost, equipment, and other factors.

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Review of Battery Charger Topologies, Charging Power Levels, and Infrastructure for Plug-In Electric and Hybrid Vehicles

For vehicles using grid power to charge the battery, traction circuit components are not engaged during the charging time, so there is a possibility to use them in the charger circuit to have an onboard integrated charger. The battery charger can be galvanically isolated or nonisolated from the grid. Different examples of isolated or nonisolated integrated chargers are reviewed and explained. Moreover, a novel isolated-high-power three-phase battery charger based on a split-phase permanent-magnet motor and its winding configuration is presented in this paper. The proposed charger is a bidirectional high-power charger with a unity power factor operation capability that has high efficiency.

Grid-Connected Integrated Battery Chargers in Vehicle Applications: Review and New Solution

This paper reviews the current status and implementation of battery chargers, charging power levels and infrastructure for plug-in electric vehicles and hybrids. Battery performance depends both on types and design of the batteries, and on charger characteristics and charging infrastructure. Charger systems are categorized into off-board and on-board types with unidirectional or bidirectional power flow. Unidirectional charging limits hardware requirements and simplifies interconnection issues. Bidirectional charging supports battery energy injection back to the grid. Typical onboard chargers restrict the power because of weight, space and cost constraints. They can be integrated with the electric drive for avoiding these problems. The availability of a charging infrastructure reduces on-board energy storage requirements and costs. On-board charger systems can be conductive or inductive. While conductive chargers use direct contact, inductive chargers transfer power magnetically. An off-board charger can be designed for high charging rates and is less constrained by size and weight. Level 1 (convenience), Level 2 (primary), and Level 3 (fast) power levels are discussed. These system configurations vary from country to country depending on the source and plug capacity standards. Various power level chargers and infrastructure configurations are presented, compared, and evaluated based on amount of power, charging time and location, cost, equipment, effect on the grid, and other factors.

Review of charging power levels and infrastructure for plug-in electric and hybrid vehicles

For electric and hybrid vehicles that use grid power to charge the battery, traction circuit components are not normally engaged during the charging time; hence, there is a possibility of using the traction circuit components in the charger circuit to have an onboard integrated charger. An isolated high-power integrated charger based on a special electrical machine with a double set of stator windings is described. Through the reconfiguration of the motor stator windings in the charging mode, a six-terminal machine is achieved. The so-called motor/generator acts as an isolated three-phase power source after synchronization with the utility grid in the charging mode. This rotary isolated power source constitutes a three-phase boost rectifier (battery charger) with full utilization of the inverter. The motor windings are reconfigured by a relay-based switching device for the charging and traction modes. This paper presents the mathematical model of the motor/generator and explains the system's functionality for the traction and charging modes. Furthermore, the charger grid synchronization and charge control are described. Finally, the simulation results are presented for a practically designed system with a traction power of 25 kW and a possible charge power of 12.5 kW.

An Isolated High-Power Integrated Charger in Electrified-Vehicle Applications

This paper presents a compact battery-powered switched-reluctance motor (SRM) drive for an electric vehicle with voltage-boosting and on-board power-factor-corrected-charging capabilities. Although the boost-type front-end DC/DC converter is externally equipped, the on-board charger is formed by the embedded components of SRM windings and converter. In the driving mode, the DC/DC boost converter is controlled to establish boostable well-regulated DC-link voltage for the SRM drive from the battery. During demagnetization of each stroke, the winding stored energy is automatically recovered back to the battery. Moreover, the regenerative braking is achieved by properly setting the SRM in the regenerating mode. The controls of two power stages are properly designed and digitally realized using a common digital signal processor. Good winding current and speed dynamic responses of the SRM drive are obtained. In addition, the static operation characteristics are also improved. In the charging mode, the power devices that were embedded in the SRM converter and the three motor-phase windings are used to form a buck-boost switch-mode rectifier to charge the battery from utility with good power quality. All constituted circuit components of the charger are placed on board, and only the insertion of power cords is needed.

Development of a Compact Switched-Reluctance Motor Drive for EV Propulsion With Voltage-Boosting and PFC Charging Capabilities

A number of power electronic converter circuits exist for switched reluctance motor (SRM) drives which are generally applicable to most loads. A larger number of circuits exist which are suitable for particular niche applications, but which have the potential to be the most cost-effective within that niche. Due to the variable methods of operation of these circuits and the rapid progress in this field, comparisons of these circuits have so far been limited. This paper attempts to bring together the sum total of power converter topologies so far published for SRM drives. A novel classification methodology is presented. The power converters are compared using a straightforward total semiconductor VA per phase sum, and the relative cost of the drive system elements is considered.

Power electronic converters for switched reluctance drives

A new circuit is presented which allows a switched reluctance motor to operate from AC mains or a low voltage battery supply. In addition the AC mains can be used to charge the battery. The switched reluctance motor is used as the voltage-changing transformer, potentially reducing the cost of the system. The operation of the drive is explained, and results of an experimental prototype are presented.

Forward converters for dual voltage switched reluctance motor drives

An entirely new class of dual voltage switched reluctance drives is presented. New power converter circuits are introduced, which allow a switched reluctance motor to operate from either an AC mains or a battery supply, with minimal extra power semiconductor components and no extra transformer. Battery charging is achieved without additional components. These converters offer considerable cost savings and flexibility when compared with conventional solutions to the problem of creating a system that can operate from both AC mains supply and battery.

C. Pollock

Papers

Power electronic converters for switched reluctance drives

Forward converters for dual voltage switched reluctance motor drives

New class of dual voltage converters for switched reluctance drives