Studies of inverter ratings of BDFM adjustable speed drive or generator systems

Abstract

This paper discusses the inverter ratings of BrushIt can be shown (Appendix A) that for an ideal BDFM less Doubly-Fed Machine (BDFM) adjustable speed drive (ASD) operating at constant torque the control winding rating, S2, is or generator (ASG) systems. Based on the per phase equivalent related to the machine rating, Smn, by circuit model, the ratings of the two inverters in a bidirectional converter are evaluated individually. An approach to minimise the total inverter rating is presented, taking into account power = 2 factor constraints of the power grid. The effects of speed S m-f2 7-3 deviation and control winding excitation on the inverter ratings I i 3 are discussed. Predictions of inverter ratings are presented with Equation (3) has been conventionally used to determnine the experimental verification. A design example is also provided in covreraig3] 4.Hwe,asaeulofteeiwhich the total inverter rating is minimised for a practical BDFM tacnerte ragntiing [3],u[].aHoevras an resulkoate rnutnesis-a based ASG system. tne,mgeiigidcacsadlaaeidcacsi Index Terms-BDFM, inverter rating, ASD, ASG practical BDFM, calculations based on an ideal BDFM need to be modified for a full evaluation of the converter rating.

Operating charts for the Brushless Doubly-Fed Machine (BDFM)

“…Thus we have a controllable variable speed generator or drive. Because the converter only processes the slip power its rating can in principle be only a fraction of the machine rating, the size of the fraction being determined by the speed range required [2], [9], [10].…”

Study on speed sensorless vector control of Brushless Doubly-Fed Machine

“…This machine is a forthcoming low cost candidate for applications with variable speed requirements, such as the adjustable speed drive and variable speed generation [1][2]. The special design of BDFM electromagnetic has studied in many papers in recent years [3][4][5][6].A number of control algorithms have been developed for BDFM, such as direct torque control [7][8], vector control methods in rotor speed two-axis rotating coordinate mathematical model [9][10], double synchronous speed two-axis rotating coordinate mathematical model [11][12].…”

“…According to (2) and (20), the adjustable model for the flux linkage of the power winding can be given as follows: The BDFM simulates under the load at L T =20N.m and the rotor speed changed from 400 r/min at time t=1s to 600 r/min at time t=2s. Fig.4a gives the simulation result of the actual and estimated rotor speed.…”

Development of a Wound Rotor Brushless Doubly Fed Machine Based on Slot MMF Harmonics

“…Brushless doubly fed machines (BDFMs) possess many advantages and hence have attracted strong interest of research and application, especially for adjustable speed drives and variable speed generators [1][2][3][4]. The BDFM has two stator windings: a power winding with p 1 pole-pairs is connected directly to the grid, and a control winding with p 2 pole-pairs is connected via a power electronic converter, as illustrated in Fig.…”

“…The machine works in the synchronous operating mode with a constant speed, which is independent of the load. From (1), the rotor speed in rpm can be determined as As the control winding is connected to the grid via the electronic converter, the rotor speed can be adjusted by varying the converter frequency, f 2 , according to (2).…”