ELECTRO-MECHANICAL-THERMAL MODELING AND STABILITY OF PULSED POWER LOADS ON A DC NETWORK

Modern military aircraft are developing larger pulsed power loads varying from new weapon technologies to advanced avionics and other electrical equipment. Pulsing power loads emulate a pulse width modulated signal which have non-linear destabilizing effects on the electrical system. Additionally, these devices have thermal properties that can induce electrical stability issues at low and high temperatures and various pulsing load conditions. These non-linear electrical stability issues carry through to the mechanical and thermal systems of the aircraft and can damage components. The MATLAB/Simulink workspace is used to simulate a non-linear model of an aircraft’s electrical-mechanicalthermal (EMT) system. This system includes electrical generation with constant and pulsing power loads, mechanical fluid pumping, and thermal cooling systems. The goal of the EMT model is to demonstrate the destabilizing effects caused by both the thermal coupling of the pulsing load and the large signal analysis of the PWM signal. An operational boundary of the power pulsed device is found by varying the duty cycle for a given pulse period and power load based on bus voltage transients and voltage drop limits. The system is defined metastable for a given set of parameters if the system experiences periods of stability and instability based on varying operating points. Regions of complete stability, metastability, marginal metastability, and instability are determined based on bus voltage transient tolerances. Analyzing the marginally metastable boundary layer, thermal analysis is performed at different points of equivalent average power and varying pulse energy. Post processing the results determines the most efficient operational region of the system given thermal and electrical requirements