T. Wu

Accelerated simulation of complex aircraft electrical power system under normal and faulty operational scenarios

The more-electric aircraft concept (MEA) is one of the major trends in modern aircraft electric power system (EPS) engineering. The concept results in a significantly increased number of onboard loads driven by power-electronics. Development of appropriate EPS architectures, ensuring the power system integrity and assessment of overall system quality and performance under possible normal and abnormal scenarios requires extensive simulation activity. At the same time, the increased use of tightly-controlled motor drives and power electronic converters can make the simulation of the large-scale EPS impractical due to enormous computation time or numerical non-convergence due to the model complexity. Hence, there is a strong demand for accurate but time-efficient modeling techniques for MEA EPS simulations. This paper reports the development of a functional models library capable of maintaining good accuracy up to a specified frequency range. The library is applied to study the performance of a twin-generator example EPS under both normal and faulty regimes. The attained improvement in simulation time confirms the performance of the developed functional models for the study of complex MEA EPS architectures.

Accelerated functional modeling of aircraft electrical power systems including fault scenarios

The more-electric aircraft concept is a fast-developing trend in modern aircraft power systems and will result in an increase in electrical loads fed by power electronic converters. Finalizing the architectural bus paradigm for the next generation of more-electric aircraft involves extensive simulations ensuring power system integrity. Since the possible number of loads in an on-board power system can be very large, the development of accurate, effective and computational time-saving models is of great importance. This paper focuses on development of a modeling approach based-on functional representation of individual power system units. This provides for possibility of fast simulation of a full generator-load power system under both normal and fault conditions. The paper describes the modeling principle, illustrates the acceleration attainable and shows how the functional representation can handle fault scenarios.

Aircraft Power System Stability Study Including Effect of Voltage Control and Actuators Dynamic

This paper describes a stability analysis of aircraft ac frequency-wild power systems with constant power loads (CPL). In contrast to previous publications, the proposed analysis method employs the dq modeling approach instead of the state-space averaging (SSA) and average-value modeling (AVM) methods to derive power-electronic converter models for stability studies. This results in lower order models and allows the modeling of vector-controlled converter elements where the SSA and AVM methods are not easily applicable. The resulting model can be combined with models of other power system elements expressed in terms of synchronously rotating frames (generators, front-end converters, vector-controlled drives, etc.). The paper analyzes the stability of frequency-wild power systems for both load and parameter variations and takes into account controlled generator voltage dynamics and electromechanical actuator dynamics. The stability margins are assessed and compared with those for power systems with the ideal voltage source and the ideal CPLs. The study is supported by intensive time domain simulations that support the theory.

A fast dynamic phasor model of autotransformer rectifier unit for more electric aircraft

This paper presents a dynamic phasor model of the autotransformer rectifier unit (ATRU) for the more-electric aircraft power system study. This model considerably reduces the complexity in modeling of an aircraft power system making it more practical to model the electrical power system for transient and stability analysis. The developed phasor model of the ATRU is based on the development of a non-switching fundamental component model of the ATRU, in which the switching behavior of the 12-pulse diode rectifier is represented by a dc transformer. The developed phasor model is capable of accurately modeling both ac- and dc-side transients. The computation time demanded by this phasor model is significantly reduced compared to the benchmark model. Simulation results show that the dynamic phasor model of the ATRU is nearly 500 times faster than the corresponding benchmark model.

More-electric aircraft electrical power system accelerated functional modeling

The development of future more-electric aircraft (MEA) is a major trend in modern aircraft electric power system (EPS) engineering that results in a significantly increased number of onboard loads driven by power-electronics. Development of appropriate EPS architectures, ensuring the power system integrity, stability and assessment of overall system quality and performance under possible normal and abnormal scenarios requires extensive simulation activity. The increased use of power electronics can make the simulation of the large-scale EPS impractical due to enormous computation time or even numerical non-convergence due to the model complexity. Hence, there is a strong demand for accurate but time-efficient modeling techniques for MEA EPS simulations. The paper reports the development of a functional models library capable of significant improvement in simulation time whilst maintaining good accuracy up to a specified frequency range. The application of the library is demonstrated on the example study of the performance of a twin-generator example EPS under both normal and faulty regimes.

High speed modeling approach of aircraft electrical power systems under both normal and abnormal scenarios

The more-electric aircraft concept is a fast-developing trend in modern aircraft power systems and will result in an increase in electrical loads fed by power electronic converters. In order to ensure the power system integrity and investigate overall system performance under possible normal and abnormal scenarios, extensive simulation studies need to be undertaken to study the generator-load dynamic overview. The increased use of the motor drive system and power electronic converters will make the simulation study of the large-scale aircraft power system suffer from impractical computation time. Even worse, the simulation cannot be converged due to the model complexity. There is a growing need for accurate and time efficient model for the aerospace application. This paper presents the simulation study of a twin-generator aircraft power system based on the functional representation of individual power system units. Such a twin-generator aircraft power system will be studied under both normal and abnormal operation conditions. It is demonstrated that the functional model of the power system units can be integrated to study a complex aircraft power system with high simulation speed. The acceleration in computation time attainable shows the performance of the functional modeling approach.

Accelerated functional-level modeling of more-electric aircraft electrical power system

The more-electric aircraft concept (MEA) is one of the major trends in modern aircraft electric power system (EPS) engineering that results in a significantly increased number of onboard loads driven by power-electronics. Development of appropriate EPS architectures requires intensive simulations to ensure the system integrity, requested quality and performance under possible normal and abnormal scenarios. At the same time, the increased use of tightly-controlled motor drives and power electronic converters can make the simulation of the large-scale EPS impractical due to enormous computation time or numerical non-convergence due to the model complexity. This paper addresses the development of a functional models library capable of significant improvement in simulation time whilst maintaining good accuracy up to a specified frequency range. The library application is demonstrated on the example study of the performance of a twin-generator example EPS under both normal and faulty regimes.