Ivan Subotic

Onboard Integrated Battery Charger for EVs Using an Asymmetrical Nine-Phase Machine

This paper considers an integrated onboard charger for electric vehicles that incorporates an asymmetrical nine-phase machine and an inverter into the charging process. The charging is from three-phase mains, and it employs exclusively the power electronic components that already exist on board the vehicle and that are mandatory for the propulsion. No new elements are introduced. Moreover, the charging is achieved without any hardware reconfiguration since the existing elements and their connections are not altered during the transfer from propulsion to the charging mode. Instead, the operating principle is based on additional degrees of freedom that exist in nine-phase machines. These degrees of freedom are employed to avoid electromagnetic torque production in the machine during the charging process, although currents flow through its stator windings. The configuration operates with a unity power factor and is capable of vehicle to grid (V2G) operation as well. A detailed theoretical analysis is given, and the control for the charging/V2G and propulsion modes is discussed. Theoretical analysis is validated by experiments for charging, V2G, and propulsion operating regimes.

Isolated Chargers for EVs Incorporating Six-Phase Machines

This paper considers two isolated solutions for fast charging of electric vehicles (EVs). The isolation is located on the grid side (off board), whereas the rest of the charging apparatus is placed on board the EV, and it entirely consists of the existing power electronics components that would be otherwise used only for propulsion. Thus, substantial savings on space, weight, and cost are achieved. The considered configurations fully incorporate either a symmetrical or an asymmetrical six-phase machine, as well as a six-phase inverter, into the charging process. Due to the nature of the connections, torque production is avoided during the charging/vehicle-to-grid (V2G) modes of operation. Thus, the machines do not have to be mechanically locked, and their rotors naturally stay at standstill. Control schemes for both configurations are elaborated, and theoretical results are validated by experiments for the two configurations in both charging and V2G modes.

An EV Drive-Train With Integrated Fast Charging Capability

This paper proposes a new class of on-board chargers for electric vehicles (EVs). Instead of being placed on-board as a separate unit, the three-phase (fast) chargers reutilize the existing components in EVs, which are already used for the propulsion. These are primarily the inverter and the machine, which however have to be multiphase (with more than three phases). The concept is valid for all multiphase propulsion drives with a prime number of phases higher than three and a single neutral point in motoring and is illustrated in detail for the five-phase inverter/five-phase machine configuration. During the charging mode, electromagnetic torque is not produced in the machine so that the rotor does not require mechanical locking. Hardware reconfiguration between propulsion and fast charging is required, but it is achieved with only two switches, which are the only two nonintegrated elements. The integrated topology is explained in this paper, together with the control scheme, and extension from five phases to higher phase numbers is illustrated using the seven-phase system as an example. Finally, the propulsion-mode operation with complete suppression of low-order harmonics, which map into the second plane, is achieved for the five-phase machine. Experimental verification of theoretical results and proposed control is provided for both charging and vehicle-to-grid mode of operation, as well as for propulsion.

On-board integrated battery chargers for electric vehicles using nine-phase machines

The paper considers on-board battery charging of electrical vehicles (EV) using a three-phase voltage source and a nine-phase propulsion motor. The nine-phase inverter and induction machine are fully integrated into the charging process. The proposed integrated on-board battery charger has an advantage of unity power factor operation with no torque production in the machine during the charging mode. Moreover, there is no need for any hardware reconfiguration between the charging and propulsion mode. The principle of the charging mode operation is based on the additional degrees of freedom that exist in nine-phase machines and that can be conveniently utilized to achieve charging through the machines stator windings with zero electromagnetic torque. Detailed theoretical analysis is reported for asymmetrical and symmetrical nine-phase systems. For both systems control in the charging mode is discussed, and the theoretical considerations are validated by simulations.

Single-Phase On-Board Integrated Battery Chargers for EVs Based on Multiphase Machines

The paper considers integration of multiphase (more than three phases) machines and converters into a single-phase charging process of electric vehicles (EVs) and, thus, complements recently introduced fast charging solutions for the studied phase numbers. One entirely novel topology, employing a five-phase machine, is introduced and assessed jointly with three other topologies that use an asymmetrical nine-phase machine, an asymmetrical six-phase machine, and a symmetrical six-phase machine. In all topologies, both charging and vehicle-to-grid (V2G) mode are viable. Moreover, all are capable of unity power factor operation. A torque is not produced in machines during charging/V2G process so that mechanical locking is not required. Hardware reconfiguration between propulsion and charging/V2G mode is either not required or minimized by using a single switch. Theoretical analysis of operating principles is given, and a control scheme, applicable to all topologies and which includes current balancing and interleaving strategy, is developed. Finally, operation of all topologies is compared by means of experiments in both charging and V2G mode, with a discussion of influence of current balancing and interleaving strategy on the overall performance.

Multiphase integrated on-board battery chargers for electrical vehicles

The paper considers on-board battery charging of electrical vehicles (EVs) using a multiphase voltage source and a multiphase propulsion motor. The multiphase inverter and the multiphase machine are fully integrated into the charging process. The proposed integrated on-board battery charger has an advantage of unity power factor operation with no torque production in the machine during the charging mode. The principle of the charging mode operation is based on the additional degrees of freedom that exist in multiphase machines. It is shown that they can be conveniently utilised to achieve charging through the machines stator winding with zero electromagnetic torque. Detailed theoretical analysis is reported for a five-phase system, with a subsequent generalization to other multiphase systems with other higher odd numbers of phases. A mathematical model of a multiphase voltage source rectifier (VSR) is developed, its control in the charging mode is discussed, and the concept is validated by simulation.

An integrated battery charger for EVs based on an asymmetrical six-phase machine

The paper considers a novel battery charger topology for electrical vehicles (EVs) that utilises an asymmetrical six-phase propulsion machine. A six-phase inverter and the machine are fully integrated into the charging process. The proposed integrated battery charger has the advantages of unity power factor operation and zero average torque production in the machine during the charging mode. The operating principles are based on the additional degrees of freedom that exist in multiphase machines and it is shown that asymmetrical six-phase machines can be conveniently utilised to achieve charging through the machines stator winding while developing zero electromagnetic torque. Detailed theoretical analysis is reported for the asymmetrical six-phase charging system. A mathematical model of the six-phase voltage source rectifier (VSR) is given, control in the charging mode is discussed, and the theoretical considerations are validated by simulations.

A review of single-phase on-board integrated battery charging topologies for electric vehicles

The paper provides an extensive overview of single-phase on-board integrated battery chargers for electric vehicles (EVs). Although commercial EVs are still to be equipped with integrated chargers, a multitude of topologies have been proposed for integration. Therefore, the need for classification arises. This paper aims to give an overview of topologies based on functionality of their integrated components. Moreover, it attempts to provide an extensive analysis of their operating principles. All the topologies are classified into three major groups. At first, topologies in which only the converter is integrated are considered. This is followed by configurations based on switched reluctance machines (SRM) in which both the converter and the machine are integrated. At last, the integration of both converter and induction machine (IM) or permanent magnet machine (PM) is elaborated within the third group. Here an example of obtained experimental results is also given. Finally, a short quantitative comparison of the topologies is provided in a table format.

An integrated battery charger for EVs based on a symmetrical six-phase machine

The paper considers a novel battery charger topology for electrical vehicles (EVs) that utilises an asymmetrical six-phase propulsion machine. A six-phase inverter and the machine are fully integrated into the charging process. The proposed integrated battery charger has the advantages of unity power factor operation and zero average torque production in the machine during the charging mode. The operating principles are based on the additional degrees of freedom that exist in multiphase machines and it is shown that asymmetrical six-phase machines can be conveniently utilised to achieve charging through the machines stator winding while developing zero electromagnetic torque. Detailed theoretical analysis is reported for the asymmetrical six-phase charging system. A mathematical model of the six-phase voltage source rectifier (VSR) is given, control in the charging mode is discussed, and the theoretical considerations are validated by simulations.

A Fast On-Board Integrated Battery Charger for EVs Using an Asymmetrical Six-Phase Machine

The paper considers a novel fast charging topology for electric vehicles (EVs). Instead of being made as a separate unit, the proposed on-board charger utilizes power electronics components that already exist inside the vehicle, namely an asymmetrical six-phase propulsion motor and a six-phase inverter. The charger can operate at unity power factor, and is capable of vehicle-to-grid (V2G) operation as well. Additional degrees of freedom of the six-phase machine are employed in order to transfer a part of excitation from the torque producing to non-torque/flux producing plane of the machine. Consequently, electromagnetic torque is not produced in the machine during the charging/V2G process, so that the rotor does not have to be mechanically locked. A theoretical analysis of the operating principles is reported, and simulation results are given for both charging and V2G mode of operation.