Hassan Ali Kojori

Three-Leg/Four-Leg Matrix Converter Generalized Modulation Strategy—Part I: A New Formulation

The generalized modulation strategy of the conventional matrix converter (MC), i.e., three-leg MC, was previously developed using the duty-cycle space vector (DCSV) representation of switch duty cycles. This paper uses the DCSV representation of switch duty cycles to develop a new formulation of the generalized modulation strategy for one-, three-, and four-leg MCs. The four-leg MC, unlike the three-leg MC, is capable of providing a neutral connection at the output side of the MC. The neutral connection enables the four-leg MC to operate as a power supply providing a balanced, regulated, and fixed-frequency voltage for balanced and unbalanced loads, including the single-phase load. The generalized modulation strategy of the four-leg MC in this paper is developed in the context of power supply applications. Using the new formulation of the generalized modulation strategy, the direct duty-cycle modulation strategies based on DCSV calculation are developed for one-, three-, and four-leg MCs, which are referred to as the DCSV-based modulation strategy of the MC. Part I of the paper formulates the DCSV-based modulation strategy of the three- and four-leg MCs.

Three-Leg/Four-Leg Matrix Converter Generalized Modulation Strategy—Part II: Implementation and Verification

Part I of this paper has proposed a duty-cycle-space-vector (DCSV)-based modulation strategy for three- and four-leg matrix converters (MCs). This paper develops a digital DCSV-based modulation strategy for the three- and four-leg MCs based on the results of Part I of this paper. The digital DCSV-based modulation strategy is implemented in a DSP-field programmable gate array (FPGA) platform. The objective is to reduce the calculation time of the modulation algorithm by performing the following: 1) reducing the total number of instructions needed to implement the modulation algorithm in the DSP and 2) implementing parts of the modulation algorithm in an FPGA to generate the switching pattern. Therefore, the calculation process of the modulation algorithm is split between the DSP and the FPGA.

Arc Fault Detection and Protection — Opportunities and Challenges

This paper presents a summary of a Honeywell collaborative IRD to provide a review and characterization of existing on-line methods of arc fault detection and protection; to summarize the critical challenges and opportunities for implementing on-line arc fault detection and protection for aerospace next generation electrical power systems including high voltage AC and variable frequency systems.

Dynamic Model and Control of an AC-AC Matrix Converter Based Micro-Turbine Generation System

This paper presents a systematic approach to develop a detailed dynamic model for a matrix converter based micro-turbine generation system, capable of direct and bi-directional AC-AC power conversion. The proposed integrated micro-turbine generator and matrix converter unit operates at a much higher generation frequency of about 2200 Hz to achieve significant cost and weight reduction. It can also provide a variable-voltage, variable-frequency power in-demand for remote military/commercial applications, or to synchronize stand-alone generator units to a local/utility grid, in the context of distributed power generation system. Detailed dynamic models of the matrix converter based micro-turbine generation system, including the thermodynamic model of the micro-turbine, are presented. The models address the limitations/drawbacks of eliminating the intermediate DC-link and the higher degree of coupling and interaction among AC sides of the system that necessitate more elaborate control algorithms and an exact dynamic model of the matrix converter.