Modeling, Control and Characterization of Aircraft Electric Power Systems

A study model of advanced aircraft electric power system (AAEPS) corresponding to B767 Aircraft is developed in the PSIM9 software environment. The performance characteristics of the system under consideration for large sharing of non-linear loads are studied. A comprehensive mathematical model describing system dynamics is derived where the GSSA technique is applied for reduced-order system approximation. The transient and steady-state performance of the hybrid PEM-FC/battery APU integrated to the aircraft electric network is analyzed while different loading scenarios are taken into account. In addition, dynamic bifurcation analysis is employed to characterize the systems stability performance under multi-parameters condition. Also, the power quality of the system is assessed under various loading configurations, and the effect of installing active/passive power filters (APF/PPF) on power quality of the system is investigated for a wide range of operating frequencies

Pulse Tripling Circuit and Twelve Pulse Rectifier Combination for Sinusoidal Input Current

In this paper, a novel pulse tripling circuit (PTC) is suggested, to upgrade a polygon autotransformer 12-pulse rectifier (12-PR) to a 36-pulse rectifier (36-PR) with a low power rating. The kVA rating of the proposed PTC is lower compared to the conventional one (about 1.57% of load power). Simulation and experimental test results show that the total harmonic distortion (THD) of the input current of the suggested 36-PR is less than 3%, which meets the IEEE 519 requirements. Also, it is shown that in comparison with other multi-pulse rectifiers (MPR), it is cost-effective, its power factor is near unity and its rating is about 24% of the load rating. Therefore, the proposed 36-PR can be considered as a practical solution for industrial applications

Analysis of Five Level Neutral Point Clamped Inverter Fed from 18 Pulse ‎Output Multiphase Rectifier for Grid Tied Applications

 تلعب محولات إلكترونيات الطاقة دورًا رئيسيًا في تطبيقات معالجة الطاقة المختلفة. في كثير من الحالات ، تنشأ الحاجة إلى استخدام محولين لتحقيق معالجة الطاقة أو التكييف أو كليهما. في هذا العمل ، تمت دراسة نظام محولين يعتمد على محولين متعدد الأطوار / متعدد المستويات. الهدف الرئيسي هو معالجة طاقة التيار المتناوب من مصدر يمكن أن يكون مصدر طاقة موزع (DER) عن طريق تحويله إلى تيار مستمر قبل حقنه في نظام تيار متردد آخر. يتم استخدام مقوم متعدد الأطوار ذو 18 نبضة للهدف الأول. يتم تحقيق مهمة المعالجة الثانية ، والتي تتضمن تحويل طاقة التيار المستمر إلى التيار المتناوب من خلال محول محايد ذو خمسة مستويات مثبتة .(NPC)  النتائج المبينة تحقق فوائد المعدل متعدد الأطوار في إنتاج جهد تيار مستمر سلس. ومن جانب أخر ، تتميز NPC ذات المستويات الخمسة بميزة مثيرة للاهتمام وهي ان الجهد الأساسي ذو قيمة عالية.Power electronics converters play a major role in various energy processing applications. In many instances the need arises to use two converters to achieve power processing, conditioning or both. In this work, two converter systems are studied, which is based on two multiphase/multilevel converters. The main objective is to process AC power from a source which can be a distributed energy source (DER) by converting it to DC before injecting it into another AC system. An 18 pulse multiphase rectifier is used for the first objective. The second processing task, which involves converting the DC power back to AC is achieved by five level neutral point clamped converter (NPC). Results verify the benefits of the multiphase rectifier in producing a smooth DC voltage. On the other side, the five level NPC revels an interesting feature of high fundamental voltage

Lightweight multiple output converter development

A high frequency, multiple output power conditioner was developed and breadboarded using an eight-stage capacitor diode voltage multiplier to provide +1200 Vdc, and a three-stage for -350 Vdc. In addition, two rectifier bridges were capacitively coupled to the eight-stage multiplier to obtain 0.5 and 0.65 a dc constant current outputs referenced to +1200 Vdc. Total power was 120 watts, with an overall efficiency of 85 percent at the 80 kHz operating frequency. All outputs were regulated to three percent or better, with complete short circuit protection. The power conditioner component weight and efficiency were compared to the equivalent four outputs of the 10 kHz conditioner for the 8 cm ion engine. Weight reduction for the four outputs was 557 grams; extrapolated in the same ratio to all nine outputs, it would be 1100 to 1400 grams

Modeling and Analysis of Power Processing Systems

The feasibility of formulating a methodology for the modeling and analysis of aerospace electrical power processing systems is investigated. It is shown that a digital computer may be used in an interactive mode for the design, modeling, analysis, and comparison of power processing systems

High reliability megawatt transformer/rectifier

The goal of the two phase program is to develop the technology and design and fabricate ultralightweight high reliability DC to DC converters for space power applications. The converters will operate from a 5000 V dc source and deliver 1 MW of power at 100 kV dc. The power weight density goal is 0.1 kg/kW. The cycle to cycle voltage stability goals was + or - 1 percent RMS. The converter is to operate at an ambient temperature of -40 C with 16 minute power pulses and one hour off time. The uniqueness of the design in Phase 1 resided in the dc switching array which operates the converter at 20 kHz using Hollotron plasma switches along with a specially designed low loss, low leakage inductance and a light weight high voltage transformer. This approach reduced considerably the number of components in the converter thereby increasing the system reliability. To achieve an optimum transformer for this application, the design uses four 25 kV secondary windings to produce the 100 kV dc output, thus reducing the transformer leakage inductance, and the ac voltage stresses. A specially designed insulation system improves the high voltage dielectric withstanding ability and reduces the insulation path thickness thereby reducing the component weight. Tradeoff studies and tests conducted on scaled-down model circuits and using representative coil insulation paths have verified the calculated transformer wave shape parameters and the insulation system safety. In Phase 1 of the program a converter design approach was developed and a preliminary transformer design was completed. A fault control circuit was designed and a thermal profile of the converter was also developed

Space electric power systems study- d-c to d-c converters for nuclear-thermionic energy sources

Direct current converters used in space electric power system for nuclear-electric power suppl

Design of DC-Link VSCF AC Electrical Power System for the Embraer 190/195 Aircraft

A proposed novel DC-Link VSCF AC-DC-AC electrical power system converter for Embraer 190/195 transport category airplane is presented. The proposed converter could replace the existing conventional system based on the CSCF IDGs. Several contemporary production airplanes already have VSCF as a major or backup source of electrical power. Problems existed with the older VSCF systems in the past; however, the switched power electronics and digital controllers have matured and can be now, in our opinion, safely integrated and replace existing constant-speed hydraulic transmissions powering CSCF AC generators. IGBT power transistors for medium-level power conversion and relatively fast efficient switching are used. Electric power generation, conversion, distribution, protection, and load management utilizing VSCF offers flexibility, redundancy, and reliability not available with a conventional CSCF IDG systems. The proposed DC-Link VSCF system for E190/195 delivers several levels of 3-ϕ AC and DC power, namely 330/270/28 VDC and 200/ 115/26 VAC utilizing 12-pulse rectifiers, Buck converters, and 3-ϕ 12-step inverters with D-Y, Y-Y, and Y-D 3-ϕ transformers. Conventional bipolar double-edge carrier-based pulse-width-modulation using three reference AC phase signals and up to 100 kHz triangular carriers are used in a manner to remove all even and many odd super-harmonics. Passive low-pass filters are used to remove higher harmonics. The RL AC loads are active in connection with the synchronous and induction AC motors and also include passive AC loads. The overall power factor exceeded 85%. Total harmonic distortions for voltages and currents are below 5%, thus satisfying the MIL-STD-704F and the IEEE Std. 519 power-quality standards, while avoiding the need for active filters. Several PI and PID controllers that regulate synchronous generator DC excitation and inverter banks were designed and tuned using the continuous–cycle tuning method to offer required performance and stability of the feedback loop. Mathworks’s SimulinkTM software was used for simulation of electrical components and circuits. Several critical scenarios of aircraft operations were simulated, such as go-around, to evaluate the transient behavior of the VSCF system

Dynamic phasor modelling of multi-generator variable frequency electrical power systems

The Dynamic Phasor (DP) concept has been widely used in modelling electrical power systems. So far, the DP concept has been restricted to modelling systems with one single electrical source at a fixed fundamental frequency; either one generator or an ideal three-phase AC source. This paper aims to extend the DP modelling methodology to a wider application area. Two major achievements have been introduced: 1. application of DPs for multi-source, multi-frequency systems; 2. modelling of systems with time-varying frequencies. These two techniques enable the use of DPs to study nearly all types of Electrical Power Systems (EPS). The developed theory is validated using a twin-generator system from the More Open Electrical Technologies (MOET) project. The accuracy and effectiveness of the developed models is confirmed by comparing the simulation results of detailed switching models and DP models under both balanced and unbalanced conditions