Further to the vector analysis in the stationary plane of the behavior of a permanent-magnet brushless dc (PM BLDC) drive, this paper proposes a method of synthesizing the current supply of the motor that ensures torque ripple-free operation of the drive. The synthesis is carried out analytically by the vector approach, and the resulting current vector is then expressed in motor phase coordinates. It comes out that the current vector has a petal-shape trajectory in the stationary plane. The operation of the drive with such a current supply is extensively examined; in particular, the torque capability for an rms value of the phase currents equal to the rated one, the requirements for the voltages to be applied across the motor terminals, and the base speed in correspondence to the supply voltage saturation are determined. At last, experimental traces obtained from an in-wheel PM BLDC drive used for the traction of light electric vehicles are included to corroborate the theoretical findings.

In general, PM BLDC motors are injected with square wave phase currents through PI-PWM control in a-b-c reference plane to ensure maximum torque-per-ampere. The operation of PM BLDC motor in a stationary plane has shown considerable simplification in design, and analysis in the control techniques. The present paper considers the injection of square wave phase current through predictive current control strategies in the stationary plane. For the evaluation of performance, cases of deadbeat predictive control, hysteresis based predictive control, and finite control-set model predictive control (FCS-MPC) methods are considered. Control schemes have been designed for 48V, 660W PM BLDC motor. Comparative evaluation is carried out in terms of the harmonic components available in the current and torque, tracking of the current trajectory in the stationary plane in the low and high-speed region, and execution time of all the control methods. Considered predictive methods are tested on an experimental prototype, and control is implemented through digital Signal Processor (DSP) TMS320F28335. Evaluation leads to the conclusion that predictive control performs better than PI-PWM for reducing commutation torque ripple, keeping current harmonics under control. It is observed that predictive control strategies in the stationary plane, improve the torque-speed characteristic to the wider utilization of constant torque zone of operation as compared to conventional strategies.

For the past few years the feasibility of contactless power transfer (CPT) is being explored extensively as a future solution for charging electric vehicles (EVs). Studies report that the main obstacles in CPT are low power efficiency, misalignment tolerance, cost, range and charging time anxiety. This paper presents a review based on existing literature of the CPT systems for EV charging. Different cases of CPT technologies, their principle of operation and equivalent circuit based analysis is carried out. A discussion on compensation strategies and their effectiveness are reviewed and discussed. The design of coil systems for some city electric cars has been referenced in general. At the end recommendations and conclusions are made based on the study and analysis of the information available in literature.

Permanent-magnet (PM) brushless direct current (BLDC) drives are utilized in a variety of applications because of their inherent features and would be even more utilized if their torque performance could be improved. Indeed, when supplied with square-wave currents, the torque-speed characteristic undergoes a drop at high speeds, and a significant torque ripple arises at both low and high speeds due to the commutation phenomena. In this paper, the sinusoidal current supply of the PM BLDC motors is investigated in depth, and an analytical formulation of the torque-speed characteristic, the torque ripple, and the base speed for such a supply are found. Based on the resulting equations, a thorough convenience analysis of the sinusoidal current supply is carried out with respect to the square-wave current in the presence of the commutation phenomena, which is hereafter termed as the real square-wave current supply. Simulation and experimental tests for a study case are given to corroborate the theoretical results. Generation of the sinusoidal current references using Hall sensors is also discussed.

This article investigates the evaluation of different charging patterns of multistep constant current-constant voltage (MSCC-CV) for fast charging of a valve regulated lead-acid battery for electric vehicles. In this article, four parameters are sensed and feedback for closed-loop operation, i.e., battery temperature, terminal voltage, state of charge (SOC), and time. The battery current is dynamically adjusted in response to these four parameters for three different charging patterns. The three charging patterns of MSCC-CV by controlling 1) SOC and temperature, 2) the terminal voltage, SOC, and maintained temperature, and 3) the charging time and SOC. Further work is carried out to investigate the effects of charging strategies on battery health. As per the experimental results, it has been demonstrated that charging pattern with four-step by regulating battery terminal voltage, SOC, and maintained temperature shortens the charging time to 3.6 h as compared to conventional constant current-CV with improved battery life and health.

The present paper considers the evaluation of temperature regulated and unregulated charging strategies to select the appropriate one to ensure extended battery life with reduced charging time. Temperature regulated pulse charging (TRPC) and temperature regulated reflex charging (TRRC) are compared with the Constant current–constant voltage (CC-CV) charging strategy. In the case of CC-CV charging temperature of the battery rises with the magnitude of the current being injected and cannot be regulated without any external cooling arrangement. Impact on the State of health (SOH) and the expected lifespan of the battery are considered as the parameters of evaluation. Temperature regulated strategies are implemented through a discrete electro-thermal model, which acts as a temperature estimator. The co-efficient of the estimators corresponds to the battery parameters such as internal resistance and thermal time constants, entropy, etc. Temperature regulation is ensured in the three identified sections of charge deposited vs magnitude of the injected current. Three sections are identified as sections where the injected current is not sufficient to raise the battery temperature to set limit or not and the level of charge submitted as compared to normal charging. Experimentation is carried with 12 V, 26 Ah Valve regulated lead-acid battery to justify that increase in temperature reference of regulation allows submission of higher charge for the same charging rate. It is demonstrated that TRPC results in a significant reduction (≈60%) in charging time as compared to CC-CV and TRRC. For the same charging time as achieved with TRPC, TRPC results in almost double the expected life of operation and better SOH as compared to CC-CV and TRRC.