Visible to the public Biblio

Filters: Author is Lu, W.  [Clear All Filters]
2019-02-14
Zhao, Z., Lu, W., Ma, J., Li, S., Zhou, L..  2018.  Fast Unloading Transient Recovery of Buck Converters Using Series-Inductor Auxiliary Circuit Based Sequence Switching Control. 2018 IEEE International Power Electronics and Application Conference and Exposition (PEAC). :1-5.

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.

2017-12-20
Lu, W., Jiang, Y., Yin, C., Tao, X., Lai, P..  2017.  Security beamforming algorithms in multibeam satellite systems. 2017 IEEE 2nd Advanced Information Technology, Electronic and Automation Control Conference (IAEAC). :1272–1277.
This paper investigates the physical layer security in a multibeam satellite communication system, where each legitimate user is surrounded by one eavesdropper. First of all, an optimization problem is formulated to maximize the sum of achievable secrecy rate, while satisfying the on-board satellite transmit power constraint. Then, two transmit beamforming(BF) schemes, namely, the zero-forcing (ZF) and the signal-to-leakage-and-noise ratio (SLNR) BF algorithms are proposed to obtain the BF weight vectors as well as power allocation coefficients. Finally, simulation results are provided to verify the validity of the two proposed methods and demonstrate that the SLNR BF algorithm outperforms the ZF BF algorithm.