Integrated onboard single‐stage battery charger for PEVs incorporating asymmetrical six‐phase induction machine
2018; Institution of Engineering and Technology; Volume: 9; Issue: 1 Linguagem: Inglês
10.1049/iet-est.2018.5015
ISSN2042-9746
AutoresK. A. Chinmaya, Girish Kumar Singh,
Tópico(s)Multilevel Inverters and Converters
ResumoIET Electrical Systems in TransportationVolume 9, Issue 1 p. 8-15 Research ArticleFree Access Integrated onboard single-stage battery charger for PEVs incorporating asymmetrical six-phase induction machine K.A. Chinmaya, Corresponding Author K.A. Chinmaya chinmay.vasista@gmail.com Department of Electrical Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 IndiaSearch for more papers by this authorGirish Kumar Singh, Girish Kumar Singh Department of Electrical Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 IndiaSearch for more papers by this author K.A. Chinmaya, Corresponding Author K.A. Chinmaya chinmay.vasista@gmail.com Department of Electrical Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 IndiaSearch for more papers by this authorGirish Kumar Singh, Girish Kumar Singh Department of Electrical Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667 IndiaSearch for more papers by this author First published: 01 March 2019 https://doi.org/10.1049/iet-est.2018.5015Citations: 17AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract This study proposes an integrated battery charger for plug-in electric vehicles (PEVs) that involves an asymmetrical six-phase induction motor as propulsion drive. Proposed power electronic interface (PEI) uses a CuK-based bidirectional DC/DC converter, which is capable of performing buck/boost function during all modes of operation. It operates as a power factor correction converter during plug-in charging mode, and a single switch inverting buck/boost converter in propulsion and regenerative braking modes. Selection of a wide range of battery voltages and adequate control over regenerative braking can be achieved with the proposed multi-functional converter. In addition, size, weight and cost of the charger are also reduced, as it involves a minimum number of components compared to existing buck/boost converters used in chargers. By utilising a six-phase induction machine drive in the propulsion system, efficiency and power density of the PEI is improved. This drive even allows for further modifications to the proposed topology. An efficient indirect field-oriented control for the six-phase machine is also demonstrated in the study. The proposed PEI is highly suitable for onboard charger and propulsion system of PEVs. A laboratory prototype of the aforementioned converter and propulsion drive has been built to validate all modes of vehicle operation. 1 Introduction Increased environmental concern among research community has led to greater attention and interest towards the electrification of the transportation sector. Plug-in electric vehicles (PEVs) and hybrid electric vehicles are being considered as future means of mainstream transportation. They are also a promising solution to curb the air pollution as battery power is used to produce clean energy for these vehicles [1]. Usually, there are two types of battery chargers for PEVs: (i) off-board chargers and (ii) onboard chargers. Off-board chargers are designed with large capacity (more than 50 kW) and mounted outside the PEVs that charges the battery within 30 min [2]. The onboard battery charger (OBC) is more desired, because they are placed in the vehicle premises; thus PEVs can be charged anywhere [3]. Typically, OBC has to be in small size, lightweight and low cost. In addition, OBC should have the capability to charge the battery with a wide variation of voltages, i.e. from 100–450 [4-6]. Most PEVs use two individual converters for their OBC [2, 7]. The first converter is used to convert AC/DC with unity power factor (UPF) operation, i.e. in plug-in charging mode. The second converter is used for boosting the battery voltage as well to control the power during propulsion and regenerative braking modes. Block diagram of a conventional OBC is shown in Fig. 1a. In this system, a large number of components are utilised, which has a negative effect on size and weight of the charger. Fig. 1Open in figure viewerPowerPoint Block diagram of (a) Conventional battery charger, (b) Integrated battery charger Number of components and size can be reduced by utilising integrated onboard chargers. These integrated chargers can be designed by either utilising inverter and motor windings in charging process, or by combining DC/DC front-end converter with power factor correction (PFC) converter. The concept of utilising motor and inverter parts in charging process is not new, connecting an inverter between the three-phase induction motor and a rechargeable battery was proposed in [8]. A three-phase open-end winding induction machine along with converter has been integrated for charging process in [9]. In this configuration, during charging process, converter is connected to one end of the machine terminals and grid to the another. During this, mechanical locking is necessary in order to avoid machine rotation. To avoid mechanical locking, a multiphase with H-bridge converter is proposed in [10]. However, midpoint needs to be accessed in this topology. Multiphase machines are usually used in high-power/high-current applications. Increased power density and reliability are the key points to consider multiphase induction machines for EVs. Higher degrees of freedom offered by the multiphase machine can be beneficial in controlling and maintenance perspective [11]. A few integrated charging topologies involving different configurations of multiphase machines have been proposed in [12-14]. Torque development in a multiphase machine during charging process can be avoided through phase transposition [15]. These topologies can achieve fast charging by connecting to the three-phase grid, in order to do so inverter and motor are involved in the charging process. Battery is charged only when the vehicle is parked. Motor inductance needs to be considered while developing the control strategies. However, with the use of machine windings in plug-in charging mode, these topologies can perform only boost operation, thus using universal power station having voltage range 90–260 V is not possible. Instead of integrating DC/AC inverter used in propulsion drive for battery charging, the bidirectional DC/DC converter connected between the battery and AC/DC PFC converter can be combined to have converter for all modes as shown in Fig. 1b. Even these types of integrated converters reduce the total number of components compared to conventional onboard chargers. As battery charging does not involve any machine windings, the converter can be designed as per the requirement of PEV. Authors in [16-18] have proposed integrated front-end converters focusing especially on battery charging in all modes of operation. Converters proposed in [16, 17] do not have buck/boost operation in all modes, thus aforementioned benefits cannot be obtained. While integrated converter in [18] uses a large number of semiconductor devices; therefore, it may not be the efficient and cost-effective solution. The authors in [17, 18] utilise a large passive filter for PFC. Input currents in these two converters are discontinuous in nature which increases the overall weight and cost of the charger. In [19, 20], SEPIC-based converters have been proposed for the battery charging using three inductors, and at least one extra inductor is also required for propulsion and regenerative braking modes. Thus, the increase of magnetic components has negative effect on weight, cost and volume of the charger. In this regard, this work presents a new integrated charger consisting of a bidirectional DC/DC converter for PEVs. Fig. 2 exhibits the proposed bidirectional DC/DC CuK converter with diode rectifier. Proposed converter has voltage stepping-up and stepping-down capabilities during all vehicular modes. This allows selection of wide range of battery voltages, and battery can be charged with universal supply voltage range (100–260 V) as well as efficient control of regenerative braking energy. It also offers several advantages in PFC applications, such as continuous input and output current, inrush current limits during transients and overload condition, and lower size of electromagnetic interference filter [21, 22]. The presence of output inductor () limits the switching ripples in current reducing the associated losses. This topology would further reduce the number of components compared to other integrated/single-stage converters. In this paper, this DC/DC converter is further referred as battery side converter (BSC). Fig. 2Open in figure viewerPowerPoint Proposed bidirectional CuK converter for integrated charger in PEVs Moreover, in propulsion drive, an asymmetrical six-phase induction machine (ASIM) with two parallel connected inverters is operated. This machine increases the efficiency and improves the performance of propulsion drive. It also provides higher power in the same machine frame. Superior qualities offered by ASIM over its three-phase counterpart can be effectively utilised for EV application. Indirect field oriented control (IFOC) is applied for closed-loop control ASIM drive. Presented topology can be further improved to involve two sources in the charging process. Details regarding this have been discussed in the future scope. From here onwards, this six-phase converter supplying ASIM is referred as drive side converter (DSC). The paper is structured as follows. Section 2 presents a detailed modelling of ASIM. In Section 3, the operation of the proposed integrated charger is discussed. Control techniques adopted for BSC and DSC are described in Section 4. In Sections 5 and 6, corresponding simulation and experimental results are exhibited to verify the proposed power electronic interface (PEI) for PEVs. A comparative study of the designed topology and its future scope is discussed in Section 7. Finally, conclusions drawn from the study are given in Section 8. 2 Modelling of ASIM Among multiphase induction machines, a configuration with two three-phase winding sets has an advantage in terms of reducing the amplitude of pulsating torque significantly. However, to achieve this improved torque waveform, two three-phase sets must be displaced by , which is not a usual symmetrical displacement observed in conventional six-phase machines. This machine is the most popular one for motoring, and generating applications. It also requires less coil insulation when compared to conventional six-phase machine [23, 24]. Due to an asymmetrical distribution of winding sets, it is generally referred as asymmetrical six-phase induction machine (ASIM). The d–q-axis equivalent circuit of the six-phase induction machine is shown in Fig. 3. The voltage equations for ASIM in arbitrary frame of reference can be written as (1) where is the arbitrary reference speed, is the flux linkage and p denotes differentiation. Fig. 3Open in figure viewerPowerPoint d–q-axis equivalent circuit of dual three-phase induction machine The torque equation of the induction machine can be expressed as (2) 3 Operation of the proposed topology The proposed topology consists of an integrated BSC coupled with six-phase DSC. BSC consists of three switches, four diodes, two inductors and three capacitors. It has three modes of operation: plug-in charging, propulsion and regenerative braking, and in each mode, converter operates in continuous conduction mode. DSC consists of two parallel converters having 12 switches driving an ASIM operated with IFOC. BSC and DSC are coupled with DC link. DSC operates only during propulsion and regenerative braking modes of operation, and it remains uninterrupted during plug-in charging mode. 3.1 Plug-in charging mode In this mode, battery is charged from the grid, so only BSC operates and DSC is in stand still. In BSC, switch is pulse-width modulation (PWM) gated, and switches and are in OFF-state. The proposed converter operates as a CuK PFC converter. Operation of converter with equivalent circuits is shown in Fig. 4a. Fig. 4Open in figure viewerPowerPoint Operating modes of the converter during (a) Plug-in charging mode, (b) Propulsion mode, (c) Regenerative braking mode In stage 1, is switched ON, energy is stored in inductor through the path –––, and capacitor C transfers its energy to output capacitor and battery through the path C––––C, inductor current increases and voltage across coupling capacitor decreases. Switch is turned-OFF in stage 2, inductor delivers its energy to capacitor C, and energy stored in inductor is transferred to capacitor . By assuming the duty ratio of converter to be , the volt-second balance of any one of the inductors among and in switching period can be written as (3) Hence, one can get voltage conversion ratio, as (4) 3.2 Propulsion mode During this mode, power flows from the battery to DC-link for propelling of motor-drive system of the vehicle. DSC operates ASIM in a closed loop. BSC switches and are in OFF-state and switch is PWM gated. Operation of the converter with propulsion mode equivalent circuits is presented in Fig. 4b. Switch is turned-ON in stage: 1, battery charges the inductor through the path –––, and current through inductor increases linearly, meanwhile capacitor discharges to supply energy to the motor through an inverter. When switch is turned-OFF in stage 2, energy stored in is transferred to DC-link capacitor through the path –––. By assuming the duty ratio of converter to be , with the volt-second balance of , one can obtain (5) The voltage conversion ratio from (3) can be expressed as (6) 3.3 Regenerative braking mode In regenerative braking mode, the drive operates in generating mode and DC-link voltage increases the power flow from drive to battery. BSC switches and are in OFF-state and switch is gated through PWM signal. In this mode, braking energy of the motor is used to charge the battery and maximises the distance covered by vehicle per charge. Operation of the converter during regenerative braking is shown in Fig. 4c. By turning-ON switch in stage 1, inductor begins to charge through the path –––. Meanwhile capacitor discharges to supply energy to the battery. Switch is turned-OFF in stage 2, releases its stored energy to the capacitor and battery. By assuming duty ratio of the converter to be , with the volt-second balance of , one can obtain (7) The voltage conversion ratio from (3) can be expressed as (8) 4 Control algorithm The control strategy is divided into two parts they are, BSC control and DSC control. BSC control focuses on charging battery from the grid in plug-in charging mode, supplying power to the motor in propulsion mode and redirecting generated power to the battery in regenerative mode. In DSC control, there are only two modes of operation, propulsion and regenerative. Both modes are operated with IFOC. The control structure of PEI during different modes of converter operation is shown in Fig. 5. Fig. 5Open in figure viewerPowerPoint Control scheme of the proposed system during different modes 4.1 Control of BSC In battery control, each mode is implemented by mode selector logic. Mode selector receives the input signals such as grid voltage (), battery voltage (), electromagnetic torque (), speed () and charging power (). During battery charging from the grid, the reference charging power is divided by instantaneous battery voltage, which is input to the outer proportional–integral (PI) controller of a two-loop closed control system. The output of this controller is a reference DC signal, which is multiplied by a unit rectified sinusoidal wave to generate final reference input to inner current PI controller . This controller is used to correct the power factor at the grid side. In order to achieve accurate current tracking and make the control system robust against supply variation, a feed-forward loop is implemented in control loop. The open-loop duty cycle from (4) is added at the output of inner current controller () to arrive final reference PWM signal to switch , as shown in Fig. 5. The objective of propulsion mode is to keep the DC-link voltage constant irrespective of any load change for satisfactory operation of inverter drive system. Therefore, the outer PI controller regulates the DC-link voltage by generating reference battery current to the inner current controller , which is provided by an average current mode controller. In regenerative braking, the reference quantity is usually torque. Therefore, torque is converted into reference charging power, and this reference power is divided by instantaneous battery voltage to generate reference battery current, which is input to current controller for battery current tracking. 4.2 Control of DSC Efficient speed control of the propulsion drive is necessary for the better performance of a PEV. An effective control strategy independently controls the torque and flux in order to operate at reference speed. ASIM can be controlled by using only one set of PI controller, however this causes a flow of unbalanced current between winding sets. To avoid this, IFOC utilised in this work employs two sets of current controllers. The d-axis flux linkages are assumed to be aligned with the rotor flux-linkage vector and q-axis flux-linkages are set to zero. The rotor flux-linkages are given by (9) The rotor currents can be rewritten with respect to (9) as (10) (11) where (12) As d-axis current is responsible for flux production, it is renamed as and q-axis current is responsible for torque production, it is renamed as . The electromagnetic torque can be given by (13) where (14) The implementation methodology of IFOC involves six PI controllers. The outer PI controller is used for speed control and flux control, which generate reference currents and . Internally, four PI controllers are used to control the direct and quadrature currents of two sets of windings in ASIM. These PI controllers generate the reference voltage for PWM converters. 5 Simulation results The simulation study of the proposed converter with 1.5 hp six-pole induction motor drive in all three modes of operation is verified in MATLAB/SIMULINK environment. The parameters (listed in Table 1) used for the simulation are acquired from the laboratory prototype developed. Table 1. Simulation circuit parameters DC/DC converter grid voltage (Vg) 220V DC-link voltage (Vhv) 400V line frequency () 50Hz nominal battery voltage (Vb) 300V L1/L2 2mH Chv/CM/Cb 550/10/2200 ASIM stator resistance [rs] 4.12 rotor resistance [rr] 8.79 stator leakage inductance [Lls] 21.6 mH rotor leakage inductance [Llr] 43.3 mH mutual inductance [Lm] 234.6 mH number of poles [P] 6 Fig. 6 shows the simulation waveforms in plug-in charging mode, during which DSC is at rest, as is the case for PWM inverter and ASIM. In this mode, the battery is charged from the grid and simultaneously converter operates under PFC mode. In Fig. 6a, the grid voltage and current are in the same phase with sinusoidal shape, which shows that the converter is operating near UPF condition. The coupling capacitor C in CuK converter is always connected between input and output in switching cycle; therefore, the voltage developed across it is the sum of rectified grid and battery voltages, as shown in Fig. 6b. The battery voltage (with 20% state of charge (SoC)) and current are shown in Figs. 6c and d, respectively. In a single-stage charger, the low-frequency component of current oscillates with twice the grid (or line) frequency. This low-frequency ripple has a negligible effect on the battery, as long as voltage ripple caused due to current ripple is lower than 1.5% of the root mean square of float voltage of the batteries [16]. Fig. 6Open in figure viewerPowerPoint Simulation results during plug-in charging operation (a) Grid voltage () and grid current (), (b) Voltage developed across coupling capacitor C (), (c) Voltage across battery (), (d) Battery current () In propulsion mode, the battery delivers power to DC-link capacitor for propelling and acceleration of the vehicle. For smooth operation of vehicle, the DC-link voltage of inverter is kept constant during any change of load torque. In this work, the DC-link voltage is selected as 400 V. Dynamic performance of PEV in propulsion mode is analysed by step changing the load torque of ASIM drive. Recorded waveforms are exhibited in Fig. 7. At t = 1.5 s load toque is changed from 0 to 5 N m and again reduced to 0 at t = 2 s, during this load change, DC-link voltage is regulated at 400 V, as shown in Fig. 7a. The corresponding change in battery voltage and current are shown in Figs. 7b and c, respectively. Fig. 7d shows the change in load torque and corresponding motor electromagnetic torque . Figs. 7e–g exhibit the commensurable waveforms of rotor flux , q-axis current , and d-axis current , respectively. As it can be seen, and are constant during load variation, only change in can be observed, hence proving the applicability of FOC in propulsion mode. Fig. 7Open in figure viewerPowerPoint Dynamic operation of converter for propulsion mode. Corresponding waveforms of (a) DC-link voltage (), (b) Voltage across battery (), (c) Battery current (), (d) Machine torque ( and ), (e) Rotor flux (), (f) Quadrature axis current (), (g) Direct axis current () In regenerative braking mode, battery is charged with braking energy of the motor. The simulated waveforms of this mode are shown in Fig. 8. In this mode, machine performs as generator, and the DC-link voltage varies with the generated power. Varying DC-link voltage during regenerative braking is shown in Fig. 8a. It operates between 300 and 350 V. Battery voltage and current are shown in Figs. 8b and c, respectively. As evident from these figures, even though there is a variation in DC-link voltage, battery is charged with constant current of 2 A. It is remaining constant even after machine stops operating in braking mode, however decrease in DC-link voltage can be observed. When DC-link voltage reaches to a pre-decided minimum value, current direction changes and the battery starts supplying to drive. Variations in duty cycle waveform with DC-link voltage variations are exhibited in Fig. 8d. When DC-link voltage is more than battery voltage, the duty signal is below 0.5, thus operating in buck mode. When DC-link voltage is lower than the battery voltage, duty signal increases above 0.5 to operate the converter in boost mode. Corresponding load torque and motor electromagnetic torque during regenerative mode are presented in Fig. 8e. Figs. 8f–h show the waveforms of q-axis current , rotor flux and d-axis current . Even during this mode and are constant during load variation, only change in can be observed, thus demonstrating the applicability of FOC in a regenerative braking mode. Fig. 8Open in figure viewerPowerPoint Dynamic operation during regenerative braking mode. Corresponding waveforms of (a) DC-link voltage (), (b) Voltage across battery (), (c) Battery current (), (d) Duty cycle, (e) Machine torque ( and ), (f) Quadrature axis current (), (g) Rotor flux (), (h) Direct axis current () 6 Experimental results An experimental prototype of the PEI for PEV was built in the laboratory. It consists of a 1.5 hp, six-pole, induction machine integrated with the CuK converter for the verification of simulation results. A field-programmable gate array based dSPACE (1104) controller is used for switching of the proposed PEI. SEMIKRON IGBT switches are utilised for the six-phase converter and bidirectional DC/DC converter. Specifications of the converter and machine used for the experiment are mentioned in Table 1. Grid voltage, battery voltage, DC-link voltage, output battery current and machine currents are measured using voltage and current sensors. The grid current and power quality are measured through FLUKE power quality analyser. Fig. 9 shows the experimental results obtained during plug-in charging mode and propulsion mode. The battery current (CH-1), grid voltage (CH-2), grid current (CH-3) and battery voltage (CH-4) are shown in Fig. 9a. As it can be seen, grid voltage and currents are in the same phase with sinusoidal shape, which indicates near UPF operation of the converter. The UPF operation relives burden on supply systems and reduces the electricity usages. The low-frequency oscillations in battery current can be observed, and this depends on filter inductor connected in series with the battery. The voltage across coupling capacitor C and current through inductor are shown in Fig. 9b. The coupling capacitor voltage is the sum of battery and rectified grid voltage, thus providing verification for simulation result in plug-in charging mode. Fig. 9Open in figure viewerPowerPoint Experimental waveforms captured (a) Battery current , grid voltage , grid current and battery voltage , (b) Waveforms of coupling capacitor voltage and inductor current during charging, (c) DC-link voltage (), battery voltage () and battery current () during transition from plug-in charging to propulsion mode, (d) Dynamics of field oriented controlled ASIM, direct-axis current (), quadrature-axis current () and electromagnetic torque () The dynamic operation during propulsion mode is tested by varying drive load torque. Corresponding changes in the battery voltage () and battery current () are presented in Fig. 9c. The DC-link voltage () is been maintained at 300 V. The electromagnetic torque (Te), direct () and quadrature axis () currents of ASIM drive during IFOC are shown in Fig. 9d. As it can be observed, varies with the variation in load torque and electromagnetic torque . is constant so as the rotor flux of ASIM. In regenerative braking mode, braking energy of the motor is used to charge the battery, which leads to long run of a vehicle per charge. With 200 V of DC-link voltage, the output waveforms in this mode are exhibited in Fig. 10a. In the figure, the battery voltage is constant 150 V, negative battery current of 2 A indicates the charging of battery from propulsion drive. Generating operation of ASIM is shown in Fig. 10b. Even in this mode, quadrature axis varies with the variation in input load torque. Direct axis current is constant so as the rotor flux of ASIM. Fig. 10Open in figure viewerPowerPoint Experimental waveforms during regenerative braking operation (a) DC-link voltage (), switching pulse (), battery voltage ()and battery current () battery voltage, (b) Dynamics of field oriented controlled ASIM, direct-axis current (), quadrature-axis current () and electromagnetic torque (), (c) ASIM currents during speed reversal in stationary reference frames and , (d) Currents in synchronous reference frames and Fig. 10c depicts the machine currents in stationary frame of reference ( and ) during speed reversal. Thirty-degree phase displacement between the current waveforms of two three-phase sets can be clearly observed. Quadrature and direct-axis currents ( and ) for variation in reference speed during IFOC is exhibited in Fig. 10d. Results obtained during grid integration, battery charging and speed reversal of ASIM during regenerative braking can be verified by comparing with similar topologies presented in [3, 14, 25]. 7 Comparative analysis and future scope A comparative study of the presented charger with conventional single-stage and existing integrated chargers is presented in Table 2. To have a fair comparison, the DC/DC converters connected between the battery and DC-link are assumed to be four-quadrant bidirectional converters. In addition to these conventional chargers, other existing integrated chargers are also included in the comparative analysis. It can be seen from Table 2, the proposed converter has least components compared to those converters, which have buck/boost operation in each mode. Table 2. Comparison study of the proposed charger with single-stage chargers Converter topologies Modes of operation Switches Diodes Inductors Plug-in charging Propulsion Regenerative braking boost PFC converter boost buck/boost buck/boost 5 5 2 inverting buck/boost converter buck/boost buck/boost buck/boost 5 5 2 SEPIC PFC converter buck/boost buck/boost buck/boost 5 5 3 CuK PFC converter buck/boost buck/boost buck/boost 5 5 3 integrated converter [16] boost buck/boost buck/boost 4 4 1 integrated converter [17] boost, buck/boosta boost buck 5 1 1 integrated converter [18] buck/boost buck/boost buck/boost 6 9 1 proposed integrated converter buck/boost buck/boost buck/boost 3 4 2 a Boost in positive half cycle and buck/boost in negative half cycle. As the proposed topology utilises a six-phase drive, it can be further modified to utilise two different sources in the charging process as shown in Fig. 11. Battery charging through six-phase machine winding with single-phase grid has been discussed in [26]. With adapting these modifications, a secondary source like solar PV cells can be connected across switch to charge the battery even during operation. Switch is operated to perform maximum power point tracking (MPPT). As this converter provides buck/boost operation in all modes, MPPT can be effectively implemented. Inductor in the input side of the converter reduces the current ripple thus improving the operating life of the battery. Fig. 11Open in figure viewerPowerPoint PEV operated with grid and PV source for battery charging 8 Conclusion In this paper, a new PEI involving an integrated DC/DC converter and a six-phase induction machine has been proposed for PEVs. As presented in the comparative analysis, the proposed charger utilises least number of components along with providing buck/boost operation in all vehicle modes. Paper also discusses the advantages of utilising a six-phase induction motor drive instead of a conventional three-phase drive. It provides a platform for future works which can be incorporated by utilising the proposed PEI. The stepping-up and stepping-down capabilities offered by the charger in all modes of vehicle operation allows for the selection of wide range of battery voltages, and the battery can be charged with universal supply voltage range (100–260 V) as well as efficient control of regenerative braking energy. A single converter is utilised to achieve all modes of vehicle operation without influencing the charging time. The charging time of the integrated CuK converter will remain same as that of the conventional CuK converter. A six-phase machine is used in the propulsion drive to improve efficiency and reliability. Even though it increases the size of the vehicle, it allows for further improvements to include another source for battery charging. Indirect field-oriented control of ASIM drive is able to perform both motoring and generating operations. The performance of PEI in each mode has been verified by both simulation as well as hardware results. Efficient closed-loop control algorithm has been developed to control BSC and DSC in all three modes of operation. The effectiveness of the BSC controller is examined by achieving UPF operation in plug-in charging mode, regulating DC-link voltage at desired value with step change of loads in propulsion mode, and recharging of battery in regenerative braking mode. Performance of DSC controller is analysed by observing the torque and speed control in propulsion and regenerative braking mode. 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