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This paper presents a new space vector modulation (SVM) strategy for matrix converters to reduce the common-mode voltage (CMV). The reduction is achieved by using the switch states that connect each input phase to a different output phase, or the switch state that connects all the output phases to the input phase with minimum absolute voltage. These two types of states always produce lower peak CMV than the others, especially the former ones that result in zero CMV at the output side of matrix converters. In comparison with the existing SVM methods, this strategy has a very similar software overhead and calculation time. Simulation and experiment results are shown to validate the effectiveness of the proposed modulation method in reducing not only the peak value but also the root-mean-square value of the CMV. [ABSTRACT FROM AUTHOR]

Traditional local-averaged state-space modeling for peak current mode (PCM) controls fails to explain the subharmonic oscillation phenomenon when the spectrum is higher than half of the switching frequency. To address this problem, this paper presents a small-signal modeling method in the z-domain, and builds a discrete linear model for the current loop of a full-bridge DC-DC converter. This discrete model is converted into a second-order continuous model that is able to represent the system performance with a wider frequency range. A frequency-domain analysis shows that this model can be used to explain the subharmonic oscillations and unstable characteristics. This provides an engineering guideline for the practical design of slope compensation. The effectiveness of the proposed modeling method has been verified by simulation and experimental results with a prototype working in the Buck mode. [ABSTRACT FROM AUTHOR]

This paper discussed an active-bridge-active-clamp (ABAC) topology that is suitable for highpower more-electric-aircraft applications. Though conventional modulation techniques can be applied to ABAC converters, they present drawbacks, such as increased low-voltage (LV) current ripple and limited power transfer capability. To address these problems, a phase-shift-modulation (PSM) scheme is proposed to provide clean dc terminal current at the LV side while maintaining high power transfer capability and efficiency in a wide operating range. The proposed PSM has a complete switching harmonics cancellation on the LV terminals independent of the operating conditions. This results in high quality power without any ac components, thus minimizing passive filtering. In addition, when terminal voltages vary from their nominal values, the proposed PSM can improve the maximum power transfer capability of the ABAC converter compared to the conventional approach. The theoretical claims are validated by both simulation and experimental results on a 10-kW 270-V/28-V ABAC converter. [ABSTRACT FROM AUTHOR]

The capability of quality-of-service (QoS) provisioning is of particular importance for multi-hop wireless networks when the real-time applications boost in current days. The scheduling and delivery of data packets in a deficient method may probably cause network congestion, which will in turn decrease the capability of QoS provisioning in the network. To this end, we propose a joint QoS provisioning and congestion control scheme for multi-hop wireless network in this paper based on our previous works of Differentiated Queueing Service (DQS) and Semi-TCP, which provide per-packet granular QoS and carry out efficient hop-by-hop congestion control, respectively. While DQS and Semi-TCP are studied separately, we investigate the arising issues in the joint scheme and propose possible solutions accordingly, including a fast estimation of the latest departure time, a method to handle overdue packets, and an adaptive ACK scheme, as well as the design of a shared database cross-layer architecture for the implementation in the protocol stack. Simulation results show that our proposal improves the network performance in terms of goodput, delivery ratio, and end-to-end delay significantly, particularly in the scenario of mobile users. Our discussion and simulation results both indicate that the proposed joint scheme is flexible and adaptive to the dynamic multi-hop wireless network environment. [ABSTRACT FROM AUTHOR]