Common-mode voltage reduction for matrix converters using all valid switch states

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

Z-domain modeling of peak current mode control for full-bridge DC-DC buck converters

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

Geometrical Visualization of Indirect Space Vector Modulation for Matrix Converters Operating with Abnormal Supplies

Matrix Converters can be sensitive to abnormal supply conditions due to the absence of energy storage elements. This sensitivity can get worse when the Matrix Converters are modulated by a traditional Indirect Space Vector Modulation that assumes the input variables are sinusoidal and balanced. Therefore, this paper proposes a methodology for the modulation of Matrix Converters without requiring any assumption of the input voltages. The method uses a geometric representation based on the Singular Value Decomposition of the switch states to synthesize the rotating vectors of the target duty-cycle matrix. Furthermore, this paper mathematically highlights the factors that have regulate the amplitude of the output voltages and utilizes them to compensate the adverse effect of the abnormal input voltages. Experimental results presented in this paper validate that the proposed method can provide sinusoidal and balanced output currents in the presence of abnormal supply conditions

Phase-shift-modulation for a current-fed isolated DC-DC converter in more electric aircraft

A Phase-Shift-Modulation (PSM) technique is proposed for an Active-Bridge-Active-Clamp (ABAC) topology. This topology is aimed for high power more-electric-aircraft applications. The proposed PSM has a complete switching harmonics cancellation on the low voltage terminal, independently of the operating conditions by effectively interleaving inductor currents. This results in a DC current at the low voltage terminal without any AC components, thus minimizing the passive filtering requirements. Additionally, when terminal voltages vary from their nominal values, the maximum power transfer capability of the ABAC converter can be greatly improved by using the proposed PSM. In this paper, the limitations of the conventional modulation technique for the ABAC converter are introduced and analysed. Then, a PSM scheme is proposed, which can provide high quality power on the low voltage terminal whilst maintaining high power transfer capability and efficiency in a wide operating range. The theoretical claims are validated by both simulation and experimental results on a 10kW 270V/28V ABAC converter

MDPI - Special Issue "Research and Technology Development in Electric Power Systems"

Dear Colleagues, The market clearly indicates that the future of the mobility will be electric. This trend grows the electric energy market volume and opens new challenges for the research community. Production, transmission, and distribution systems are critical as well as utilization systems. The research cover also new components, design, testing and fault detection methods. This Special Issue aims to present and disseminate the most recent advantages related to the theory, design, modelling, application, control, testing of Electric Power Systems and generally all related aspects. Topics of interest for publication include, but are not limited to: - Generation methods, including renewable and classical power sources - Transmission (including HV AC/DC) system design with related protection methods and circuits - Power flow analysis and smart grid management - Failure diagnosis and detection - Active power and frequency control - Electromagnetic transients - Coordination of isolation - Protections in transmission systems - Interaction between electromagnetic transients and electromechanical transients - Power converters (modelling, design, control