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This study introduces a new method for real-time efficiency tracking and stable output power of Dynamic Wireless Power Transfer (DWPT) systems using variable capacitors. A preliminary detailed discussion and an analysis of the DWPT system are carried out to show how the system can optimize power transmission and efficiency when the relative positions of transmitter and receiver change using a dynamic real-time control of the variable capacitors belonging to the compensation networks. This paper shows a detailed model of the DWPT system, including magnetic coupling analysis, circuit dynamics analysis, and efficiency characteristics analysis, in order to modify the control input values as needed. By utilizing a group optimization strategy, the transmission efficiency can be quickly maximized without using a position detection module. Simulation results demonstrate the effectiveness of the proposed method under various dynamic conditions, achieving significant improvements in energy efficiency and transmission reliability of the DWPT system. This research provides a powerful method to increase the overall performances of DWPT systems, which will help the development of future wireless charging technology. [ABSTRACT FROM AUTHOR]

An experimental method is proposed to estimate all design specifications represented by circles in the Nyquist plane (e.g., phase margin, sensitivity, and closed-loop bandwidth) in case of closed-loop dc/dc switching converters. The method is based on the complete root contour (CRC) analysis in the root locus plane. All typical specifications for controller design are experimentally checked in case of a boost converter, using only input/output data. The main innovation of this paper is the automatic and systematic application of the CRC method to controlled dc-dc converters. The classic relay-based structure for an experimental estimation of the critical parameters (autotune variation) is compared with a different technique, called sinusoidal autotune variation, more efficient in the case of nonlow-pass systems. Index Terms--Circle criteria, performance evaluation, phase margin, switching converters.

A successful implementation of a low-cost PI-fuzzy controller for a CUK converter is presented in this paper. Properties of the proposed controller are robustness around the operating point, good performance of transient responses in changing load conditions and/or input voltage, and invariant dynamic performance in the face of varying output operating points. Simulations and experimental results have been obtained via a suitable variation of the scaling factors related to the input variables of the fuzzy controller. Index Terms--CUK converter, fuzzy controller, scaling factor.

In this paper an innovative brake, based on magneto-rheological fluids, is described. A system of Permanent Magnets, properly arranged in the device, has been designed to maximize the excitation field inside the fluid. The system has been analyzed by means of a 3D FEM code. The results in terms of magnetic flux density inside the fluid and the braking torque have been discussed. Furthermore, the magnetic torque necessary to perform the brake actuation has been calculated. Finally, some preliminary measurements on a prototype have been performed. [ABSTRACT FROM AUTHOR]

Accurate modeling of electrical drives for online testing is a relevant problem, because of their nonlinear behavior. Efficient modeling for simulation, performance evaluation, and testing must consider accurate as well as simple models. This paper proposes the application of auto-tune methods to identify equivalent Hammerstein models, where the nonlinear process is approximated by a static nonlinear element followed by a linear dynamic second or third-order model. The effectiveness of the presented procedure is first verified by simulation results, showing that Hammerstein models overcome the limitations inherent to small-signal linearizations. A standard implementation of such technique considers a relay adjustment for attempts in a heuristic way. In this paper, two innovations are proposed: the relay adjustment is automatically shifted and the method is applied for complex electric drives. Experimental results are shown in the case of a drive constituted by a dc/ac inverter supplying a single-phase induction motor and of a step-down chopper. Index Terms--Dynamic modeling of nonlinear systems, Hammerstein models, identification of electrical drives, relay automatic tuning.