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In order to achieve the purpose of extending the speed range and reducing power electronics devices for the permanent-magnet linear motor drive system, a half-centralized open-end winding (OEW) topology is studied for rail transit applications in this paper. In this topology, compared with the traditional OEW topology, the number of voltage-source-inverters (VSIs) can be reduced from four to three to drive two OEW movers and all these VSIs share a common dc bus voltage. In order to improve the steady-state performances, a four-vector phase model predictive voltage control (FV-PMPVC) is proposed in this paper. Due to the spatial distribution of phase voltage vector (PVV), an orthometric synthesis principle (OSP) is proposed to calculated the duration time for the vector synthesis, which reduces the computation burden and enhances the robustness. Comparing the existing control method, FV-PMPVC can get similar dynamic performances but better steady-state performances. Additionally, the half-centralized topology using FV-PMPVC can have same speed range while less VSIs are required. The effectiveness of FV-PMPVC is verified by experimental results. [ABSTRACT FROM AUTHOR]

This paper presents a novel active power control scheme for SRMs that are used as S/G units at MEAs; the proposed method uses a vector-controlled SAF, facilitating the acceleration of the SRM during starter mode and the efficient power control of the SRG at various operational points during generator mode. Moreover, an energy storage unit is incorporated in the SAF, aiming at enhancing the SRM's starting torque production and taking full advantage of the SRG's energy generation capability, through the appropriate phases’ magnetization regulation that is imposed by the developed adaptive SAF vector control. In addition, the proposed scheme provides enhanced FRTC during both modes of operation. The mathematical analysis is verified through MATLAB/Simulink simulations, while the performance of the S/G concept under study is evaluated via real-time CHIL tests, with the use of the dSPACE 1202 (MicroLabBox) platform and the 16-bit dsPIC30F4011 microcontroller. [ABSTRACT FROM AUTHOR]

Two-stage AC-DC converters are considered as a prominent solution for DC-type electric vehicle (EV) chargers. However, this kind of architecture suffers from high switching losses with large heatsink and DC-link capacitor volume. To relieve this issue, this paper presents a new hybrid modulation for DC-type EV chargers, where a two-phase clamped discontinuous pulse-width-modulation (DPWM) in the front-end circuit is cooperated with the variable frequency triangular-current-mode (TCM) zero voltage switching (ZVS) or its simplified implementation, i.e., boundary-ZVS (B-ZVS) strategy, in the back-end circuit. The former can stop the switching actions in the front-end stage during two-thirds of the grid period, while the AC currents are at their highest values, which can yield to the best switching loss reduction and deliver high power factor operation. Besides, TCM-ZVS or B-ZVS modulations can achieve ZVS turn-on action for all semiconductors during all operating range in the DC-DC stage to further reduce the power losses on the semiconductors. With such characteristics, the proposed strategies can reduce the switching losses of the system to the best extent, and thus allow an enhancement of the system power density by improving the power conversion efficiency. The proposed strategy is described, analyzed, validated, and benchmarked in a 5 kW SMD SiC MOSFET-based two-stage AC-DC converter. A 99% power efficiency can be achieved with the solution implementing the TCM-ZVS strategy at an output voltage of 400 V and rated power. [ABSTRACT FROM AUTHOR]

This paper presents an isolated single-stage on-board electric vehicle charger without an intermediate DC-link. Based on an isolated current-source topology, the converter features soft-switching in semiconductors regardless of load variation for the full AC line voltage range. Moreover, it requires no external snubber or clamp circuits. The power factor correction and voltage regulation are provided by a relatively simple phase shift modulation, while the amount of circulating energy is kept at minimum. The charger is distinguished by its efficiency characteristic – the maximum is achieved in the constant power charging mode. The control method, component stresses, and design constraints of the topology are analyzed. The concept is verified using a 3 kW experimental SiC-based prototype, which reaches a peak efficiency of 96.4%. Moreover, the charger has demonstrated efficiencies above 95% with the THD of 4.1% when operating in constant power mode at the maximal power. [ABSTRACT FROM AUTHOR]

LLC resonant converters are widely used in On-board Power Converter but the pumping voltage of traditional LLC converter is unavoidable under light-load conditions due to the existence of parasitic parameter. In this paper, an LLC resonant converter with damping split inductor is proposed to improve the light-load regulation capability. The original resonant inductor is divided into two parts in series. Then, a simple damping resistor connected on one part in parallel and the other part can be integrated into the transformer. Using damping split inductor, significant regulation improvements could be achieved under light-load conditions with not any change in control strategy and almost zero hardware cost. In addition, based on impedance analysis of the resonant tank, the effects of the proposed method are analyzed including voltage gain, soft switching characteristics, suppression of high frequency interference components, and system power loss. Moreover, the detailed design process and optimization conditions of the damping split inductor parameters are carefully illustrated. Eventually, the experimental results demonstrate the characteristics mentioned above for the 96 W prototype at the expense of a maximum increase in device loss of 0.85 W. [ABSTRACT FROM AUTHOR]

Most fuel cell electric vehicles require wide voltage-gain DC–DC converters to increase and equalize the relatively low voltage of fuel cell stacks with DC link bus or energy-storage devices, such as supercapacitors or batteries. This paper proposes two new non-isolated DC–DC converters suitable for such applications, which can be extended to other electric vehicles as well. The proposed converters combine the main characteristics of both quadratic Boost and Ćuk converters, offering high step-up voltage and control simplicity using only one ground referenced active power switch. Additionally, the proposed topologies present reduced voltage stress across the active power switch when compared to other boost converters. Considerations about the design of the proposed converters will also be presented. Experimental results obtained using a laboratory prototype validate the effectiveness and feasibility of the proposed topologies and its suitability for fuel cell electric vehicles. [ABSTRACT FROM AUTHOR]

Ultracapacitor (UC) based dc–dc power supplies are widely used for addressing surge power demands and to provide energy backup to critical loads. The conventional control techniques, such as unified control strategy, though ensure seamless mode transition, do not offer complete flexibility in charging and discharging controls which is crucial in UC-based backup systems. On the other hand, controls, such as independent switch control, though allow great flexibility in control, do not ensure seamless mode transition without appropriate mode-switch logic. This paper proposes a time-varying virtual resistance based mode transition control for independent switch control which not only ensures smooth, seamless transition between charging and discharging control modes but also ensures complete control over the mode transition durations. The proposed control is found to be robust to error mode identification as compared to introducing dead band between control modes. The proposed control is verified on a proof of concept experimental setup at a power level of $P_o=65$ W, voltage level of $V_g=26$ V with the dc–dc converter switching at $f_{\text{sw}}=100$ kHz. The performance comparison with PWM blocking method is also evaluated where the proposed control is found to work well. [ABSTRACT FROM AUTHOR]

In this paper, a comprehensive sliding mode control (SMC) loop design for single-phase interleaved totem pole (ILTP) power factor correction (PFC) converters in electric vehicle onboard charger applications is proposed. The major objectives of the proposed SMC are to improve the converter dynamics, ensure a tight output voltage regulation under fast load fluctuations, and maintain a unity power factor. The sliding mode coefficients are selected to ensure both small signal and large signal stability for the robustness of the converter in wide operating conditions. As verification to the proof-of-concept, a hardware prototype of a single-phase ILTP PFC is developed and tested to validate the effectiveness of loop design by the load transient tests. The steady state results exhibit a power factor >0.995 and total harmonic distortion <3% at 800 W load power. At a 25% step-change in load power, SMC achieves 80 ms settling time, which is approximately 200 ms faster than the conventional PI control. [ABSTRACT FROM AUTHOR]

A 12-V motor drive system using an onboard battery is promising in vehicle applications, e.g., to rotate an air pump to adjust its air delivery to the burner, thereby providing autonomous exhaust temperature control for the conventional diesel engine vehicle. The 12-V/1-kW motor drive system proposed in this paper consists of a series-resonant LLC MOSFET full-bridge converter, which provides high-efficiency power transfer by implementing zero voltage switching and boosts the dc bus to $\sim$300 V, and an insulated-gate bipolar transistor inverter, which provides the high-side phase currents to a 1-kW/6000-r/min brushless dc motor (BLDC). This design secures the high efficiency, low cost, and low volume. Meanwhile, with the variable output voltage of this dc/dc converter, this paper realizes a commutation torque-ripple reduction method, which will minimize the mechanical vibration. Experimental results on this prototype system demonstrate that: 1) the LLC dc/dc part efficiency is 97.6% with 92% of the inverter efficiency; and 2) the motor commutation torque ripple is reduced close to zero. [ABSTRACT FROM PUBLISHER]

In this paper, an innovative method to minimize the intermediate dc-link capacitance in a cascaded two-stage combination of a three-phase six-switch power factor correction (PFC) and phase-shifted full-bridge (PSFB) dc/dc stage is introduced and analyzed. The proposed strategy has a significant impact on the minimization of the overall system weight and volume. Fundamentally, the method is based on minimizing the switching fundamental component of the dc-link current and is established by imposing a separate constraint on the phase duty ratios without compromising the unity PFC action. Furthermore, the control loop takes care of regulating the intermediate dc-link voltage along with the final output voltage. A 6 kW laboratory prototype of the integrated three-phase PFC and PSFB dc/dc as a part of auxiliary power unit in more-electric airplanes is developed and designed to validate the proposed algorithm. The experimental results show a conversion efficiency of 95.4% at full load, input total harmonic distortion of 4.1%, power factor of 0.998, output voltage ripple of ±1%, and a reduction of dc-link capacitor by 60%. [ABSTRACT FROM AUTHOR]

This paper proposes an interleaved equalization architecture for series-connected lithium-ion battery strings, which can deliver energy from a battery module to the cells in the next adjacent battery module, resulting in an enhancement of the equalization current and efficiency. Particularly, the global equalization is achieved without the need of additional stage circuits to balance among modules, leading to a small size and low cost. A two-module equalizer based on resonant LC converter and buck converter with soft switching is implemented to verify the validity of the proposed interleaved architecture. Furthermore, a self-learning fuzzy logic control (SLFLC) algorithm is employed to online regulate the equalization period based on the voltage difference among cells and the cell voltage, not only greatly abbreviating the balancing time but also effectively preventing overequalization. The SLFLC has the outstanding advantages of high balancing precision, easy implementation, and strong robustness. Experimental results demonstrate that the proposed equalizer has good balancing performances with soft switching and high efficiency, and achieves zero-voltage gap among cells. Moreover, the proposed SLFLC algorithm abridges the total equalization time by about 27%, and reduces the equalization cycles by about 59% compared with the traditional control algorithm. [ABSTRACT FROM AUTHOR]

A nonisolated single-stage on-board charger for electric vehicles has been proposed to increase system efficiency and power density in previous works. However, its ability to achieve high efficiency is limited by variations in the electric utility and battery, especially during the step-down operation. This paper proposes an advanced control algorithm that improves system efficiency in the step-down mode by controlling each switch asymmetrically using a phase-shift control. The proposed algorithm consists of only one controller, which prevents transient states from causing variations in the controller. The algorithm decreases the magnitude and ripple of the inductor current, which improves the charging efficiency by approximately 4.1% over at the 3.7-kW full load that of the conventional algorithm in the step-down mode, and measured total harmonic distortion and power factor are 3.2% and 0.995, respectively. [ABSTRACT FROM AUTHOR]

This paper proposes a novel integrated synchronous buck converter for the auxiliary power supply system of electric vehicles, which achieves multiple independently regulated outputs with reduced switching components in comparison with the conventional separate buck converters. In order to obtain a better understanding of the proposed converter, operational principle and performance characteristics of a simplified dual-output buck converter are introduced in detail, as an example. The analysis shows that zero-voltage-switching operation and lower conduction losses could be attained. In addition, its dynamic behavior is similar to the conventional buck converter and thus the controller design is simple. Finally, experimental results based on a prototype circuit in which two inductors are integrated into one magnetic core to achieve further reduced cost are demonstrated to verify the advantages. [ABSTRACT FROM PUBLISHER]

Due to an increasing in-vehicle electric load demand, a new 48-V electric system architecture proposed by German premier car manufacturers has been gaining increasing attention recently for electrified vehicles. In this paper, a multiple-voltage bus converter for the 48-V and existing 12-V dual supply system, providing additional flexible dc bus voltages, is proposed. The proposed converter can provide a dual flexible dc voltage bus and an additional dependent voltage bus while simultaneously managing the 12-V supply net using only one single-leg switch pole and a diode. The additional dc voltage buses will provide more options to accommodate variable electric load components in a vehicle, improving their power density. Due to the multiple control objectives, the single-leg pole requires a multimode switching strategy to regulate the additional bus voltages. To improve the onboard vehicle system reliability and performance, an impedance network structure is implemented in the converter to obtain a dead-time-free pulsewidth modulation (PWM). Simulation and experimental results are presented to verify the feasibility and effectiveness of the proposed structure and control method. [ABSTRACT FROM PUBLISHER]

This paper deals with a control method that adapts the dc bus voltage of electric traction systems using permanent-magnet synchronous machine (PMSM) fed by bidirectional $Z$-source inverter (ZSI) or other improved topologies. This control allows reducing both the overestimation of the dc bus voltage and losses in the inverter. The sliding-mode control (SMC) method is used to control the $Z$-source converter, whereas flatness-based control is proposed to drive the actuator and generate the peak dc bus voltage reference. Flatness-based control is chosen because the actuator transients are well mastered. Extra shoot-through zero inverter states are inserted by means of implemented algorithm on a space-vector-modulation (SVM) scheme. Different short-circuit strategies are studied and compared according to constraint criteria. Both simulation and experimental results are presented and discussed to validate the proposed voltage adaptation strategy and the improvement on global efficiency. [ABSTRACT FROM AUTHOR]

In this paper, a control strategy is presented for a high-performance capacitively loaded loop (LLC) multiresonant dc–dc converter in a two-stage smart charger for neighborhood electric vehicle (NEV) applications. It addresses several aspects and limitations of LLC resonant dc–dc converters in battery charging applications, such as very wide output voltage range while keeping the efficiency maximized, implementation of the current mode control at the secondary side, and optimization of burst mode operation for current regulation at very low output voltage. The proposed control scheme minimizes both low- and high-frequency current ripples on the battery while maintaining stability of the dc–dc converter, thus maximizing battery life without penalizing the volume of the charger. Experimental results are presented for a prototype unit converting 390 V from the input dc link to an output voltage range of 3–72 V dc at 650 W. The prototype achieves a peak efficiency value of 96%. [ABSTRACT FROM PUBLISHER]

This paper presents the design and control of a high-efficiency multiphase dc–dc converter for a truck auxiliary power unit (APU) fed by a fuel-cell stack. The power-stage design methodology and the operation of the designed power stage used to achieve high efficiency are described in detail. To operate the designed converter as a truck APU, the mode transfer control scheme, where smooth transitions of the voltage and current control modes are necessary, is proposed, and the current controller design procedure is described. A 5-kW four-phase dc–dc converter prototype is built with the proposed power-stage configuration, and the proposed control strategy is applied to control the dc–dc converter. The efficiency of the converter is more than 99.5% at near 10% load and above 98% from 10% to 100% load range. Simulations and experimental results are provided to verify the feasibilities of dc–dc converter operation and the proposed control strategy in the truck APU application. [ABSTRACT FROM PUBLISHER]

Plug-in hybrid electric vehicles (PHEVs) will play a vital role in future sustainable transportation systems due to their potential in terms of energy security, decreased environmental impact, improved fuel economy, and better performance. Moreover, new regulations have been established to improve the collective gas mileage, cut greenhouse gas emissions, and reduce dependence on foreign oil. This paper primarily focuses on two major thrust areas of PHEVs. First, it introduces a grid-friendly bidirectional alternating current/direct current ac/dc–dc/ac rectifier/inverter for facilitating vehicle-to-grid (V2G) integration of PHEVs. Second, it presents an integrated bidirectional noninverted buck–boost converter that interfaces the energy storage device of the PHEV to the dc link in both grid-connected and driving modes. The proposed bidirectional converter has minimal grid-level disruptions in terms of power factor and total harmonic distortion, with less switching noise. The integrated bidirectional dc/dc converter assists the grid interface converter to track the charge/discharge power of the PHEV battery. In addition, while driving, the dc/dc converter provides a regulated dc link voltage to the motor drive and captures the braking energy during regenerative braking. [ABSTRACT FROM PUBLISHER]

This paper presents a high-gain boost converter (three-level converter and transformerless converter) for fuel cell (FC) vehicle applications. An original nonlinear control law based on the flatness principle for distributed dc generation is studied. Utilizing the flatness property, we propose simple solutions to the system performance and stabilization problems. The design controller parameters are straightforward and autonomous at the operating point. To validate the proposed method, a prototype FC power converter (1.2-kW three-level boost converter) is developed in the laboratory. The proposed control law is implemented with a digital estimate in a dSPACE 1104 controller card. The experimental results from the laboratory using a 1200-W and 46-A polymer electrolyte membrane FC (PEMFC) verify that this is a good control scheme. [ABSTRACT FROM PUBLISHER]