Survey of Conventional &new Generation Advanced D.c.braking System of 3-phase Squirrel Cage Induction Motor with Vfd

Any variable frequency drive requires an efficient and controlled braking system. Therefore, different braking techniques have been the subject area of researchers to enhance the performance as well as overall life of the drives. In this paper, a literature study is made of various existing braking methods, focused on induction motor (IM) drive performance. The braking methods are compared and summarized based on speed range, braking time and efficiency of 3-phase squirrel cage IM drive. Finally, an advancedD.C. braking technique is presented where braking torque in terms of varyingD.C.signal is injected into the stator windings using fully controlled Space Vector Pulse Width Modulation pulses (SVPWM). A method has been described for providing occasional fast, smooth and controlled braking torque from a non-regenerative VFD, without additional power circuits. Simulations are performed in MATLAB/Simulink, tested and validated on Digital signal processor (DSP) based drive. Test results are presented in this paper.