The use of doubly fed reluctance machines for large pumps and wind turbines
ABSTRACT Brushless doubly-fed induction machines (BDFIMs) have been extensively researched over the last 15 years because of the possibility of using a partially rated inverter in many applications with limited speed variations. However, the special cage rotor construction and substantial rotor losses is one of the key deficiencies of these machines. A similar and extremely interesting machine, the brushless doubly-fed reluctance machine (BDFRM), has been largely ignored in comparison. This was mainly due to the fact that reluctance rotor designs were not capable of generating saliency ratios large enough to make the BDFRM competitive with other machines. However recent developments in reluctance rotors, spurred on by research into synchronous reluctance machines, have resulted in high saliency ratio cageless rotors that are economic to build. This, together with the promise of higher efficiency and simpler control compared to the BDFIM, means that further investigation of the BDFRM is warranted. This paper presents a comparative theoretical analysis of the important control properties and related machine performance/inverter size trade-offs for the BDFRM in the light of its most likely applications-large pump type adjustable speed drives and variable speed constant frequency wind power generation systems.
- SourceAvailable from: openrepository.com[show abstract] [hide abstract]
ABSTRACT: Direct Torque Control (DTC) has been extensively researched and applied to most AC machines during the last two decades. Its first application to the Brushless Doubly-Fed Reluctance Machine (BDFRM), a promising cost-effective candidate for drive and generator systems with limited variable speed ranges (such as large pumps or wind turbines), has only been reported a few years ago. However, the original DTC scheme has experienced flux estimation problems and compromised performance under the maximum torque per inverter ampere (MTPIA) conditions. This deficiency at low current and torque levels may be overcome and much higher accuracy achieved by alternative estimation approaches discussed in this paper using Kalman Filter (KF) and/or Sliding Mode Observer (SMO). Computer simulations accounting for real-time constraints (e.g. measurement noise, transducer DC offset etc.) have produced realistic results similar to those one would expect from an experimental setup.Industrial Electronics, 2009. IECON '09. 35th Annual Conference of IEEE; 12/2009
- [show abstract] [hide abstract]
ABSTRACT: The paper will put a forward a description of a realistic design for a brushless doubly-fed machine that is of practical value. It takes the form a 4-pole / 8-pole machine aimed for use in a 2 MW wind turbine over a correct speed and torque range. Previous examples discussed laboratory machines and this study takes the outcomes from these studies to formulate a procedure for sizing and designing the machine. The latest design and analysis techniques are used, with practical rotor ducting considered. Control is also addressed in the paper, in particular the assessment of sensorless reactive power control. This paper is aimed at taking the machine from a small-scale laboratory example to consideration as a large-size industrial generation and therefore it represents a step-change in the literature on the machine.Industry Applications Society Annual Meeting, 2008. IAS '08. IEEE; 11/2008