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This work is concerned with conducted common-mode (CM) electromagnetic interference (EMI) emission of inverter-motor drive systems fed from a dc source. Conducted CM EMI behavior of such drive systems is analyzed by a simplified CM equivalent circuit model, from which a new method is developed to reduce CM current emission by creating a balanced Wheatstone impedance bridge around the CM voltage source. Such impedance balancing method reduces CM current filtering requirements, which usually dominates the EMI attenuation requirements in airborne motor drive systems, and can result in more compact overall system design in terms of volume and weight.

This paper presents a method to reduce common-mode (CM) electromagnetic interference (EMI) emission from electric actuators powered from PWM rectifier-inverter drives for use on more electric aircraft. An EMI model is presented first from which a simplified system CM model is developed to serve as the basis for the analysis and the development of effective CM EMI reduction methods. The proposed method is to insert a high-impedance element in series with the CM EMI voltage source, and create a low-impedance path in parallel with the high-impedance element to bypass the CM current. The method effectively reduces the amplitude of the CM voltage that drives the input and output CM current such that less filtering would be required. Experimental results from a laboratory motor drive system are presented to verify the effects of the proposed method.

This paper presents modeling and analysis of the harmonic performance of multi-pulse Transformer-Rectifier Units (TRU) and Autotransformer-Rectifier Units (ATRU) under different non-ideal operation conditions. Other than numerical simulations, the paper presents an analytical method to quantify and study the effects by describing the operation of the converters by the so-called mapping functions. Double-Fourier series method is applied to determine the Fourier representation of the mapping functions. Based on the analytical models in the frequency domain, the effects of harmonic voltage and load current harmonics are theoretically investigated.

This paper presents small-signal input impedance models for multipulse rectifiers that are widely used on more-electric aircraft (MEA) for powering variable-speed motor drives and other loads requiring dc inputs. The models are intended for MEA ac power system stability and power quality analysis using impedance-based method. Both Transformer Rectifier Units (TRU) and Autotransformer Rectifier Units (ATRU) are considered. The modeling method is based on the concept of impedance mapping which is applicable to various TRU and ATRU topologies. The basic modeling method will be reviewed, followed by application of the method to TRU and ATRU with and without inter-phase transformers. Closed-form small-signal input impedance models are then presented along with an overview of their derivation procedure. Experimental measurements from a 12-pulse TRU are also reported to validate the developed models and to illustrate TRU and ATRU input impedance characteristics.

A new method is proposed for the analysis and design of multipulse three-phase rectifiers such as 12- and 18-pulse rectifiers. The method is based on describing the voltage transformation of the multiphase transformer by a 3×N matrix when N is the number of secondary outputs of the transformer. A key advantage of the method is that the same matrix can be used to describe the current transformation through the transformer as well, avoiding the lengthy and error-prone algebra required in the existing approaches to determine the current responses of multipulse rectifiers. The transformation matrix can be further used to determine harmonic performance of the rectifier, to calculate the rectifier small-signal input impedance, as well as to identify potential triplen harmonic problems. It provides a new, general and effective mathematical tool for the analysis and design of multipulse rectifiers that are widely used in large industrial drives and aerospace systems.

This paper gives an overview of advanced power electronic circuits and control modeling techniques for power quality and dynamic stability study of airborne electrical systems. A unified modeling framework based on averaging is presented, and its applications to PWM as well as resonant and soft-switching converters are discussed in detail. Discontinuous conduction mode, peak-current control, variable-frequency PWM, and ac-dc converters with active power factor correction are among the specific topics discussed. Feasibility of automatic model generation by means of a symbolic analysis program package is also demonstrated. Compatibility among models of converters operated at significantly different switching frequencies is identified as a key issue for average-based analysis of large power electronic systems that requires future study.