Brett Jordan

Coupled Inductor Characterization for a High Performance Interleaved Boost Converter

Interleaved power converter topologies have received increasing attention in recent years for high power and high performance applications. The advantages of interleaved boost converters include increased efficiency, reduced size, reduced electromagnetic emission, faster transient response, and improved reliability. The front end inductors in an interleaved boost converter are magnetically coupled to improve electrical performance and reduce size and weight. Compared to a direct coupled configuration, inverse coupling provides the advantages of lower inductor ripple current and negligible dc flux levels in the core. In this paper, we explore the possible advantages of core geometry on core losses and converter efficiency. Analysis of FEA simulation and empirical characterization data indicates a potential superiority of a square core, with symmetric 45deg energy storage corner gaps, for providing both ac flux balance and maximum dc flux cancellation when wound in an inverse coupled configuration.

High temperature operation of a dc-dc power converter utilizing SiC power devices

Performance of a 2 kW, 40 kHz, 270 V/500 V boost dc-dc power converter as a function of temperature is reported for the following power semiconductor device combinations: Si MOSFET and Si ultrafast diode, and SiC MOSFET and SiC Schottky diode. The test results clearly demonstrate the possibility of designing 200 degC power converters utilizing SiC power semiconductor devices

A comprehensive multi-mode performance analysis of interleaved boost converters

Interleaved power converter topologies have received increasing attention in recent years for high performance applications. In this paper, a comprehensive multi-mode performance analysis is presented for interleaved boost converters operating over the entire duty ratio range (0 ≤ switch duty ratio ≤ 1) under the continuous conduction mode (CCM) and two discontinuous conduction modes (DCMs). With inductor coupling factor and converter loading as parameters, key performance indicators such as the dc voltage gain, input ripple current, inductor ripple current, and output ripple voltage are presented in a normalized form to aid the converter design process. Transitions among the CCM and two DCM modes are clearly defined for the entire switch duty ratio range. Advantages of DCM operation such as reduced switching loss at the expense of undesired ringing are discussed. The comprehensive multi-mode analysis has been experimentally verified using a 250 W, 70 kHz prototype converter unit.

Performance analysis of a multi-mode interleaved boost converter

Interleaved power converter topologies have received increasing attention in recent years for high performance applications. The advantages of coupled interleaved boost converters include increased efficiency, reduced size, reduced electromagnetic emission, faster transient response, and improved reliability. In this paper, a comprehensive performance analysis is presented for a multimode interleaved boost converter operating under the continuous conduction mode (CCM) and two discontinuous conduction modes (DCMs). With inductor coupling factor and converter loading as parameters, key performance indicators such as the dc voltage gain, input ripple current, inductor ripple current, and output ripple voltage are presented in a normalized form to aid the converter design process. Transitions among the CCM and two DCM modes are clearly defined as part of the analysis. Advantages of DCM operation such as reduced switching loss at the expense of undesired ringing are discussed. The analysis presented is experimentally verified using a 250 W, 70 kHz prototype converter unit.

Lumped Node Thermal Modeling of EMA with FEA Validation

Abstract : The development of electromechanical actuators (EMAs) is the key technology to build an all-electric aircraft. One of the greatest hurdles to replacing all hydraulic actuators on an aircraft with EMAs is the acquisition, transport and rejection of waste heat generated within the EMAs. The absence of hydraulic fluids removes an attractive and effective means of acquiring and transporting the heat. To address thermal management under limited cooling options, accurate spatial and temporal information on heat generation must be obtained and carefully monitored. In military aircraft, the heat loads of EMAs are highly transient and localized. Consequently, a FEA-based thermal model should have high spatial and temporal resolution. This requires tremendous calculation resources if a whole flight mission simulation is needed. A lumped node thermal network is therefore needed which can correctly identify the hot spot locations and can perform the calculations in a much shorter time. The challenge in forming an accurate lumped node thermal network is to determine all the suitable thermal resistances and capacitances of the thermal network. In this paper we present an FEA-based lumped node network and its simulation of a mission profile. This model is based on a detailed FEA model to locate the hot spots, to determine the network parameters and to verify its effectiveness. The model can also deal with the nonlinear behavior of the EMA system introduced by phase-change materials (PCM) if thermal energy storage is needed, and temperature-dependent magnetic properties. This model can also be incorporated into lumped node magnetic and electric model to develop a full multi-physics, multi-scale simulation engine. This engine can accurately analyze the complete EMA system in a systematic scale and whole-mission duration.

Dynamic Heat Generation Modeling of High Performance Electromechanical Actuator

All-electric aircraft is a high priority goal in the avionics community. Both increased reliability and efficiency are the promised implications of this move. But thermal management has become a significant issue that must be resolved before reaching this goal. Advanced analysis technologies such as finite element method and intelligent control systems such as field oriented control are being used to better understand the source of the heat and to eliminate as much of it as possible. This paper addresses the motivation behind allelectric aircraft and gives an overview of some of the considerations in cooling, simulation and modeling, and control, with an example of one control scheme which is being developed.

Integrated Nonlinear Dynamic Modeling and Field Oriented Control of Permanent Magnet (PM) Motor for High Performance EMA

This paper describes the integrated modeling of a permanent magnet (PM) motor used in an electromechanical actuator (EMA). A nonlinear, lumped-element motor electric model is detailed. The parameters, including nonlinear inductance, rotor flux linkage, and thermal resistances, and capacitances, are tuned using FEM models of a real, commercial motor. The field-oriented control (FOC) scheme and the lumpedelement thermal model are also described.

Dynamic Testing of Electromechanical Actuators Using Time-history Data

Abstract : A commercial electromechanical actuator (EMA) is to be dynamically tested with predetermined stroke and load profiles for transient thermal and electric power behavior to validate a numerical model used for aerospace applications. The EMA will follow the stroke profile representative of a real aircraft mission duty cycle. A hydraulic press will exert a corresponding load profile onto the EMA. Specialized hydraulic load control methods must be employed to meet the accuracy requirements. Two of these methods are closed-loop linearization (CLL) and displacement induced disturbance cancellation (DIDC). These methods are implemented along with an external PID compensator, and run in real-time in a series of system identification experiments to observe controller performance.

Parabolic approximation to EMA motion profiles

Parabolic curves fit physical trajectories well because of the inherent smoothness of inertial movement; and, with only a few parameters, they can fit complex paths far more effectively than linear approximations. This paper presents a method using parabolas to approximate the motion profiles to be used in driving an electromechanical aircraft actuator. This method allows the actuator to run longer tests more efficiently. The details of the scheme are explained with emphasis on its matrix manipulation and the fidelity of the approximation to the original, complex profile.