Design and Control of a Brushless Doubly-fed Machine for Aviation Propulsion PDF Download

Author: Peng Peng
Publisher:
ISBN:
Category : Electric machines
Languages : en
Pages : 200

Get Book

Book Description
Driven by the demand to reduce fuel consumption, operating cost and noise of civil aircraft, tremendous effects have been taken towards the more-electric aircraft (MEA) over the past few decades. The substantial difference between an MEA and a traditional aircraft is a higher ratio of electrical power to the total power. Two symbolic shifts differentiate an MEA from a traditional aircraft. The first is the elimination of the integrated drive generator (IDG) which mechanically converts variable jet engine speed to constant speed to generate voltage with constant amplitude and frequency. The main generator in a modern MEA is mechanically coupled with the turbine and generates high power with variable frequency. The second is the much less reliance on the pneumatic and hydraulic power. Loads originally powered by pneumatic and hydraulic power systems are now partially powered by electrical energy in a modern MEA. Both changes contribute to a fuel-efficient and light-weight MEA. The goal of flying an all-electric aircraft has spurred various designs of aircraft propulsion systems based on electrical power, among which the turboelectric distributed propulsion (TeDP) is considered as a good candidate with flexibility and reliability. In addition, there is growing consensus that electric machines and power electronics with high power density and excellent fault-tolerance capability are the key components in aircraft electric propulsion systems. More strict requirements are imposed on the large electric machines than on their counterparts in industrial or automotive applications. Any improvement in weight, size, power and reliability of electric machines is valued for aviation applications. Different from traditional electric machines, brushless doubly-fed machines (BDFM) have two sets of windings with different frequencies and pole pair numbers. It allows more freedom for speed and power control. A brushless doubly-fed machine with a reluctance-type rotor inherently provides excellent fault-tolerance capability for wide speed range operation. The usage of a fractionally-rated converter potentially increases the power density and reduce the cost of the entire drive system. These features enable brushless doubly-fed machines attractive candidates for aviation electrical propulsion system. This work proposes a turboelectric distributed propulsion based on brushless doubly-fed machines. The operating principle and electromagnetic analysis of a high-speed BDFM are elaborated. Mathematical modeling method, and as well as the torque and power formulas of a multi-BDFM TeDP are proposed. A vector control algorithm is proposed based on space-vector theory to achieve maximum torque per ampere operation for the TeDP. Simulation, hardware and experimental results of a designed high-speed brushless doubly-fed machine and its drive system are also presented in this work. In summary, a BDFM-based TeDP provides advantages over state-of-the-art aviation electric propulsion in terms of 1) smaller converter in power rating and size, 2) higher fault tolerant capability, 3) greater flexibility in speed and power control.