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High reliability and fault-tolerant operation capability are the application requirements of electric vehicles(EVs). In case of the drive system suffering from inter-turn short-circuit (ITSC) fault, it is necessary to avoid the aggravation of the fault and ensure the normal output performance, this paper proposed a torque ripple minimization control strategy for ITSC fault based on the open-winding (OW) five phase fault tolerant fractional slot concentrated winding interior permanent magnet (FTFSCW-IPM) motor drive system with common DC bus. Once the ITSC fault is detected, the fault phase is active open-circuit (OC) (null the current of the normal part in the fault phase) and connected to a voltage sensor. In this way, the torque ripple minimization control strategy can deal with the OC fault and ITSC fault. For the OC fault, the equal amplitude phase current modulation strategy is adopted based on the carrier-based pulse width modulation (CPWM). For the ITSC fault, this paper proposed a feedforward compensation approach to eliminate the influence of the short-circuit loop current. The novelty of the proposed method is that the compensation can be real-time estimated using the zero-sequence voltage (ZSV) and zero-sequence current (ZSC), even the ITSC level changes. Simulation and experimental results demonstrate the effectiveness and feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

The electrification of a forced induction system (FIS) has emerged as a feasible solution for low greenhouse gas emission and high fuel economy in passenger cars and light-duty trucks. A high-speed electric motor in conjunction with the conventional FIS has numerous benefits including better transient response and higher engine output power. A single-phase brushless dc (BLDC) motor possesses a number of attractive features for this application including high efficiency, low cost, robustness, and high-speed operation capability. However, it generates higher torque ripple than that of three-phase BLDC motor due to the lack of alternate phases and phase current distortion. This paper proposes a new torque ripple minimization control technique, which has a linearly decreasing reference voltage to regulate phase current. The analytical estimation and experimental results verify that the new control technique reduces the motor vibration while improving the maximum speed and the efficiency of the motor drive. [ABSTRACT FROM AUTHOR]

Under the unbalanced condition of grid voltages, the second-order harmonic voltage ripple will appear on the DC bus of the three-phase PWM rectifier due to the existence of the negative sequence voltages. In addition, the total harmonic distortion (THD) of the grid currents will increase correspondingly. In this paper, the coupling mechanism between the DC bus voltage ripple and the grid harmonic currents is revealed. Based on the situation above, a grid harmonic current suppression method is proposed. Compared with existing methods, the proposed method has the advantages in the following three aspects. Firstly, the proposed method does not require either the extraction of positive/negative sequence or the positive/negative sequence current control, which can highly reduce the complexity of the system. Secondly, the grid current harmonics can be reduced by an improved proportional quasi resonant (IPQR) controller. Thirdly, the IPQR controller has little effect on the parameter design of the control system, which facilitates the control design. Finally, the experiments show the accuracy of the theoretical analysis and the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In single-phase AC charging system for electric vehicles (EVs), the single-phase pulse width modulation (PWM) rectifier with deadbeat predictive current control (DPCC) is characterized by fast current dynamic response and simple algorithm. However, in steady state, the performance of the DPCC is affected by the circuit parameters mismatch and control delay, which will result in the AC side power-factor degradation and the input current distortion. Moreover, the performance of dynamic response to load mutation can be improved, as the traditional DPCC adopted PI controllers in the voltage loop. In this paper, an improved deadbeat control method is proposed. In the current loop, the AC side voltage compensation parameter is proposed to improve the power factor and reduce the total harmonic distortion (THD). The voltage loop uses an active disturbance rejection controller (ADRC), which improves the dynamic performance of the system. The feasibility and effectiveness of the proposed deadbeat control method is verified by simulation and experimental results. [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]

Traditional current control methods for a single-phase rectifier in an electric traction drive system suffer from either long response time or nonzero steady-state error. A novel current vector control strategy in stationary-frame is therefore proposed, in this paper, to improve the control performance of a rectifier. The mathematic model of the single-phase two-level pulse rectifier was first analyzed by complex space vector. Then, the principle of the proposed current control method was described. Based on this, the implementation and parameter tuning method of the current control algorithm based on a space complex vector in a two-phase stationary coordinate system are presented. Moreover, two kinds of general current control algorithms are analyzed and compared with the proposed algorithm to demonstrate the advantages of the proposed algorithm. The proposed control scheme absorbs advantages of the conventional control schemes, including fast response, zero steady-state error, and active and reactive power independent control, but overcomes their shortcomings. Finally, the theoretical analysis is verified by means of simulation as well as a hardware-in-loop experimental test on an experimental laboratory setup and some comparisons with conventional current control algorithms prove the advantages of the utilized method. [ABSTRACT FROM AUTHOR]

This paper presents a single-inductor multiple-input single-output (SI-MISO) boost converter with a deadbeat-based control method. The proposed deadbeat-based control has the capability to simultaneously conduct the power regulation from multiple inputs and the output voltage regulation for the SI-MISO boost converter. The advantages of the proposed method are less component count, lower system cost, compatibility for arbitrary number of inputs, fast response, and simplicity for implementation. Hence, the SI-MISO boost converter is a promising interface for the regulation of multiple energy sources as a standalone power system, which can be utilized in electric vehicle applications. To verify the performance of the proposed deadbeat-based control method, a laboratorial prototype of the SI-MISO boost converter is built. The steady-state and dynamic operations are investigated based on the prototype. The experimental results demonstrate that input power and output voltage of the SI-MISO boost converter can be effectively regulated by the proposed control method. The comprehensive comparison with the existing methods is conducted to further illustrate the advantages of the proposed deadbeat-based method. [ABSTRACT FROM AUTHOR]

For impulse-radio ultrawideband (IR-UWB) communications, pulse overlap often occurs in indoor dense multipath environments, where the time separation between adjacent received multipaths is typically less than one pulsewidth. Moreover, due to its low power spectral density (PSD) and its overlay usage model, the IR-UWB signal is also vulnerable to narrow-band interference (NBI) of a high power level. Taking the effect of pulse overlap into account, this paper presents an optimal prerake/postrake UWB transceiver design to counteract NBI. The prerake/postrake uses rake structures at both the transmitter and the receiver. The optimum weights for the prerake and postrake are derived by maximizing the signal-to-inference-plus-noise ratio (SINR). Furthermore, an adaptive scheme is proposed to achieve the optimal solution iteratively. Simulations show that the proposed prerake/postrake and the adaptive scheme can significantly eliminate the adverse effect of NBI and thus perform well even in the presence of severe NBI. [ABSTRACT FROM PUBLISHER]

This correspondence paper explores the efficiency of common propulsion systems present in electric multirotors or drones with normal (tractor) and inverted (pusher) configuration rotors. The work fills the gap in the literature by providing extensive data on such configurations with combination of different brushless dc motors and propellers. The results will inform the development of electric multirotors that are more efficient by changing the propulsion system type. [ABSTRACT FROM AUTHOR]

High reliability is important in motor driving system for electric vehicle applications. In this paper, a fault-tolerant direct torque control for a five-phase fault-tolerant fractional-slot concentrated-winding interior-permanent-magnet (FTFSCW-IPM) motor under the open-circuit condition of a single phase is proposed, in which an analogous three-phase space vector pulse width modulation (SVPWM) control strategy is adopted. The DTC system for the five-phase PM motor based on healthy SVPWM has several advantages of improved currents and low torque and flux ripples. To achieve the fault-tolerant operation of the SVPWM-DTC system, an analogous three-phase SVPWM strategy is proposed. The proposed SVPWM fault-tolerant control scheme is achieved by the division of six sectors and the reconfiguration of six equal nonzero voltage vectors, which is quickly computed and easily realized. In addition, based on a 2-kW FTFSCW-IPM motor prototype, the good performances of the proposed fault-tolerant drive are validated by both simulations and experiments, in which the average torque and low torque ripple during fault can be maintained. Finally, the dynamic performances under healthy and fault-tolerant conditions are measured. The results show that the proposed analogous three-phase SVPWM control can offer good dynamic performance, which is comparable to the healthy SVPWM. [ABSTRACT FROM AUTHOR]

Thermal and state-of-charge (SOC) imbalance is a well-known issue that causes nonuniform aging in batteries. The modular battery based on cascaded converters is a potential solution to this problem. This paper presents bipolar control (BPC) of a modular battery and compares it with previously proposed unipolar control (UPC) mode in terms of thermal/SOC balancing performance and energy efficiency. The BPC needs four-quadrant operation of a full-bridge (FB) converter using bipolar pulsewidth modulation (PWM) inside each module, whereas UPC only needs a half-bridge (HB) converter with unipolar PWM. The BPC, unlike UPC, enables charging of some cells while discharging others. An averaged state-space electrothermal battery model is derived for a convex formulation of the balancing control problem. The control problem is formulated on a constrained linear quadratic (LQ) form and solved in a model predictive control (MPC) framework using one-step-ahead prediction. The simulation results show that BPC, without even requiring load current variations, gives better balancing performance than UPC but at the cost of reduced efficiency. The UPC requires at least current direction reversal for acceptable balancing performance. In short, the UPC is a more cost- and energy-efficient solution for electric vehicle (EV) and plug-in hybrid EV applications, whereas the BPC can be beneficial in applications involving load cycles with high current pulses of long duration. [ABSTRACT FROM PUBLISHER]

This paper presents a six-phase current reconstruction scheme for dual traction inverters in hybrid electric vehicles (HEVs) with a single dc-link current sensor. During the phase current reconstruction, one of the inverters is proposed to operate using active vectors, whereas the other inverter operates using nonactive vectors. An advanced phase-shift scheme for all pulsewidth-modulated (PWM) signals based on the sequence of duty cycles is implemented. PWM signals are considered in three types: large, medium, and small duty cycles. Then, the minimum phase-shift scheme is applied to each type of PWM signal to ensure the minimum duration of the active vector for stable current reconstruction. With this proposed phase-shift scheme, the maximum allowable modulation index and dc-link voltage utilization are improved. In addition, the relationship between the minimum required time for stable phase current reconstruction and the maximum allowable modulation index is derived theoretically. The effectiveness of the proposed method is verified by both simulation and experimental results. With this scheme, cost and volume of dual inverters in HEVs are reduced, considering the lower number of current sensors. [ABSTRACT FROM PUBLISHER]

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]

The urban rail transit system has the characteristics of wide voltage fluctuation, intermittent and strong impact load, limited heat dissipation capacity. The high-speed flywheel energy storage system (FESS) is used to provide network voltage stability and regenerative braking energy recovery due to its high power density, unlimited number of charge-discharge cycles, fast response and environmental friendliness. When considering the design of high-speed FESS converter with 3.6 kHz fundamental frequency and 330 kW rated power used in 1500 VDC urban rail transit system, the two-stage topological converter reduces the efficiency and increase the cost and size, meanwhile, the series-connected converters and the multilevel converter increase the difficulties of control and insulation, so the two-level and I-type three-level converters of high-speed FESS are designed and evaluated. Several comparisons are made by detailed experimental data from the perspective of the traction load characteristics of the 1500 VDC urban rail transit system and the technical and economical requirements of the high-speed FESS. It is found that the three-level converter has significant advantages in matching the traction load characteristics for its higher duty cycle capability, as well as improving the technical and economical performances such as efficiency, du/dt value, THD, voltage stability, and reducing the cost by 40% when compared to the two-level converter. While in the future MW class high-speed FESS development, the maximum output power capacity of the three-level FESS is relatively lower than that of the two-level FESS. The theoretical analyses were verified by experiments. [ABSTRACT FROM AUTHOR]

Aiming to shed light on the operation of fully-digital transmitters, we present the first symbol-rate baseband model that makes explicit the inter-symbol interference introduced by the RF pulse-width modulation (RF-PWM). The proposed model expresses the transmitter output as symbols plus interference, paving the way for the derivation of in-band performance metrics of the communication system. Then, we find an approximation for the error vector magnitude that allows us to evaluate the impact of the oversampling ratio, the statistics of the transmitted symbols and the shaping pulse in the transmitter performance. Another advantage of the model is that simulation times are much shorter since it does not require interpolation to appreciate the PWM distortion. To obtain the model, we first assume a generic expression of the continuous-time signal to be transmitted, in terms of the information symbols and the reconstruction filter. This allows us to express the nonlinear differential equation that models the intrinsic distortion also in terms of the sent symbols. Then, we elaborate on the formulation of the continuous-time RF-PWM distortion to procure an expression of the received signal sampled at symbol rate. The article concludes with a numerical validation of the model, and a simulation of the bit error rate of the system. [ABSTRACT FROM AUTHOR]