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Title: High performance rectification for future power networks
Author: Araujo-Vargas, Ismael
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2007
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A technology move, known as the More Electric Aircraft, is resulting in the use of electric motor drives and power electronic converters to replace the hydraulic, pneumatic and mechanical power systems that are used onboard aircraft. The application of high performance multi-pulse rectifiers as the input stage of the power conversion circuits for actuators and motor drives is becoming typical in aircraft systems, and the growing use of rectifier-front-end equipment is resulting in more stringent power quality limits being placed on load current harmonics. This Thesis describes the development of an active injection technique for a 12-pulse rectifier that uses the natural harmonic ripple of the rectifier to produce high-quality input currents. The injection technique utilises a single low-rated active device that carries approximately 2.9% of the load current, and it potentially offers two important advantages over previously reported ripple injection techniques. First, there is no need to use an injection transformer, avoiding the associated weight penalty. Second, the active device may be driven with either low-frequency pulses or high-frequency, pulse-width modulation to produce 24/36-pulse operation or multi› level PWM operation respectively. The resultant input currents are almost sinusoidal, the line current THD being 2.36%for the 24-pulse operation and 1.06%for the PWM operation. The active injection technique uses a phase-locked loop control strategy that synchronises the injector operation with the harmonic ripple frequency of the rectifier. The circuit operation, idealised waveforms, modulation strategy and design are explained together with Micro-Cap simulation and experimental results, which are presented from a 4 kW prototype to illustrate and examine the circuit performance in both 24/36-pulse and PWM operating modes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available