Airborne Power System Research Articles

Modified CBPWM-Controlled Semi-Two-Stage AC-DC Converter for Low-Frequency Pulsed Load

Pulsed load poses a significant challenge to the safe operation of the airborne power systems. This article proposes a semi-two-stage ac dc converter with power decoupling function for the airborne power system with pulsed load. The semi-two-stage converter provides two dc ports, in which one dc port with lower voltage is the output port connected to the pulsed load, while the other dc port is the decoupling port and interfaced with the output via a buck converter. A power flow path with single conversion stage from the ac input to the load exists, and the steady-state power can be directly fed to the load. Hence, higher efficiency can be achieved comparing to the conventional two-stage solution. After analyzing the effect of the zero-sequence components in modulation strategy on power flow control, a simple and effective carrier-based pulsewidth modulation (CBPWM) with adjustable zero-sequence injection and variable carriers is proposed to achieve the power regulation of the two dc ports. The detailed operation principle and control scheme of the semi-two-stage ac dc converter are presented, and the effectiveness and feasibility of the proposed solution for pulsed load are validated by simulation and experimental results.

Performance degradation analysis of reliability growth of airborne power supply based on logistic regression

With the improvement of reliability design of nonlinear airborne power supply system, it is more difficult to analyze the performance degradation of components under lean failure data in reliability growth test. In this paper, a state space model of performance degradation was established for nonlinear airborne power system, and the method of performance degradation modeling and analysis was studied by using nonlinear logistic regression process. Taking electrical, mechanical and thermal stress as characteristic failure loads, a nonlinear logistic regression analysis model was established to describe the performance degradation under comprehensive stress. The state of the degradation space is divided by the Markov distance, and the performance degradation trajectory is transformed into the degradation state space by using the maximum likelihood model and correlation degree model of observed variables, the degradation space trajectory of the performance of the characteristic parameters under multi-input variables is obtained. The correctness and validity of the nonlinear logistic regression model and the degradation process analysis method are verified by the test on the brushless motor reliability test platform.

Inversion of frequency in key schemes for airborne power systems

The process of formation of curves of electric voltage and current are considered for the converter devices of airborne power supply systems. It is shown that discrete principle allows to provide high quality of electric energy on the output of such devices at maximum energetic losses

Bayesian Algorithm Based on Airborne Power Supply System

The design assessment of airborne power system can be started from designing stage of the power system. It can analyse and evaluate the status of the power system. The key to the designation of evaluation system is how to evaluate the performance of the power system. With airborne power system as the research object, combined with military standard GJB181A - 2003,and through the onboard power system for co-test, it can establish a set of objective assessment strategies and methods can achieve comprehensive evaluation on the performance of airborne state of power system. Based on bayesian theory evaluation method. With 28 v low voltage dc onboard power system as an example, intercepting the multiple sets of test and analysis data to evaluate instances test and comparative analysis of the model, a comprehensive evaluation and the rationality of the evaluation result is verified by relevant experimental data.

Fault Diagnosis Expert System for Electric Power System of the Large-Scale UAVs Based on Virtual Instrument

In this paper, a test system hardware platform based on PXI bus system is proposed to test the airborne power system and typical power distribution structure of large-scale Unmanned aerial vehicles (UAV). By researching system structure, analyzing failure mode and designing fault tree, fault diagnosis expert system is designed to test the airborne power system in large-scale UAVs, where a forward reasoning expert knowledge base based on extension rule is built to solve the non-exact inference in complex system via introducing certainty factor. The experiments illustrate that the proposed system can effectively improve the intelligent level of test system and has good application prospects.

Nonlinear Current Control of Single-Phase PFC Converters

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A set of new nonlinear current control methods are presented for single-phase power factor corrected ac–dc converters. These control methods combine input current feedforward with partial feedback based on the switch current to achieve sinusoidal input current and unity input power factor. They overcome the limitations of conventional linear (average) current control in terms of control bandwidth and sensitivity to noise, resulting in high-performance input current control which can meet the most stringent harmonic current limits required by variable-frequency airborne power systems. The control methods are also ideally suited for integrated mixed-signal implementation, requiring an analog current controller which is very simple, much less sensitive to noise than conventional linear feedback control, and independent of converter and control design parameters; and a digital controller which operates with a sampling frequency much lower than the switching frequency. Detailed development of the control methods is presented along with their stability analysis and circuit implementation. A prototype converter and its operation are also presented to validate the analysis and to demonstrate the performance of the control methods. </para>

Dymola-based modeling of SRD in aircraft electrical system

A rapid-calculation nonlinear model of switched reluctance drives system (SRD) is modularly developed based on Dymola, a new object-oriented modeling software. The SRD is constructed as a subsystem model for the aircraft electrical system model library. The purpose is to build a generic, expandable, and relatively complete airborne model library, then conveniently assemble a system-level model of airborne power system to simulate its dynamic performance, and then alleviate the difficulty in design and optimization of airborne power system during the conceptual design phase.

Compact, lightweight, superconducting power generators

Many future military systems will depend heavily on high electrical power input ranging from hundreds of kilowatts up to the multimegawatt level. These weapon systems include electromagnetic launch applications as well as electrically driven directed energy weapons (DEW), such as high-power microwaves and solid-state lasers. These power generation subsystems must often be packaged using limited space and strict weight limits on either ground mobile or airborne platforms. Superconducting generators made of high-temperature superconductors (HTS) will enable megawatt-class airborne power systems that are lightweight and compact. Also discussed briefly are new advances in HTS conductors and refrigeration systems furthering the development of HTS power systems.