MODELLING AND PERFORMANCE ANALYSIS OF INDUCTION MOTOR UNDER DYNAMIC BRAKING OPERATION

Abstract

In today’s world, industries are dependent upon induction motors due to their vast applications and economical aspects like robust nature, reliable operation, efficiency, lower cost, etc. The application of these motors in mills, conveyors systems, pumps, winders, wind tunnel operation, elevators, and so on. Due to their wide area of operation and usage, it is necessary to analyze and improve the braking part of these motors. So, it is very important to implement a braking system that can meet the requirement of industrial operations. Dynamic braking is achieved by developing a stationary magnetic field in the motor. The advantage of using dynamic brakes is ease in the regulation of speed and reduction in mechanical losses. A quick braking system means the motor should be coming to rest from its speed of operation within seconds or lesser. There can be multiple varying factors like different load torques, different braking time, different braking schemes or different machine parameters. That’s the reason the implementation of an effective braking system has been an area of research over time. There are several conventional and long-known methods of braking of induction machines, which are widely known. In induction machines, the major issue has been the temperature rise as it determines the maximum loading. An optimum braking scheme controls the stopping of motor drive in a smallest time with producing minimum heating and is hence cab be used effectively where regular and quick braking is required. A set of two improved dynamic braking schemes on 3 phase induction motor is implemented in this thesis, which is able to cover the drawbacks of the existing conventional braking system and hence eliminates the requirement for the implementation of a multistage braking scheme which is complex in nature that has been implemented by many scholars over the time. The v effectiveness of this braking system is analyzed under varying parameters. The power flowing in the motor during and after braking is also important to analyze its electrical model and losses at various stages. Thus, the power flow calculation from the input terminal to the power available at the shaft is done to analyze the power of the machine during the transients and steady-state braking. The effect of sudden braking on the motor drive on winding parameter and its thermal outcome is also analyzed in the SIMULINK environment. The performance of the braking system is studied and the ceasing limit due to different braking schemes is also estimated. In this Thesis, a detailed analysis covering electrical and thermal modelling and implementation of improved dynamic braking of an induction motor is performed in SIMULINK environment.