Biblio
Interior permanent magnet (IPM)-type linear oscillating actuators (LOAs) have a higher output power density than typical LOAs. Their mover consists of a permanent magnet (PM) and an iron core, however, this configuration generates significant side forces. The device can malfunction due to eccentricity in the electromagnetic behavior. Thus, here an electromagnetic design was developed to minimize this side force. In addition, dynamic analysis was performed considering the mechanical systems of LOAs. To perform a more accurate analysis, instantaneous inductance was considered according to the mover's position.
This paper presents a sequence switching control (SSC) scheme for buck converters with a series-inductor auxiliary circuit, aiming at improving the load transient response. During an unloading transient, the series inductor is controlled as a small equivalent inductance so as to achieve a fast transient regulation. While in the steady state, the series inductor behaves as a large inductance to reduce the output current ripple. Furthermore, on the basis of the proposed variable inductance circuit, a SSC control scheme is proposed and implemented in a digital form. With the proposed control scheme the unloading transient event is divided into n+1 sub-periods, and in each sub-period, the capacitor-charge balance principle is used to determine the switching time sequence. Furthermore, its feasibility is validated in experiment with a 12V-3.3V low-voltage high-current synchronous buck converter. Experimental results demonstrate that the voltage overshoot of the proposed SSC scheme has improved more than 74% compared to that of the time-optimal control (TOC) scheme.
This paper presents the analysis and the design of a ferrite permanent magnet synchronous generator (FePMSG) with flux concentration. Despite the well-known advantages of rare earth permanent magnet synchronous generators (REPMSG), the high cost of the rare earth permanent magnets represents an important drawback, particularly in competitive markets like the wind power. To reduce the cost of permanent magnet machines it is possible to replace the expensive rare earth materials by ferrite. Once ferrite has low remanent magnetization, flux concentration techniques are used to design a cheaper generator. The designed FePMSG is compared with a reference rare earth (NdFeB) permanent magnet synchronous generator (REPMSG), both with 3 kW, 220 V and 350 rpm. The results, validated with finite element analysis, show that the FePMSG can replace the REPMSG reducing significantly the active material cost.