Simulation Study On Influence Of PWM Schemes On Induction Motor Iron Losses

Induction motors have the advantages of simple structure,easy manufacturing,reliable operation,etc.Iron loss is a key part of the total energy loss of the induction motor.Precise calculation of the iron loss is essential for the motor designers to use appropriate amount of electromagnetic materials,prevent the motors from being overheated,and increase the motors service life.Moreover,the global energy issue becomes increasingly serious,whilst the induction motors consume a large part of the electric energy.Therefore,energy saving for the induction motors is rather important.In this thesis,influence of pulse width modulation(PWM)schemes on the iron loss of inverter-fed induction motors is studied,and a new modulation method is proposed to reduce the energy loss of the inverter-fed induction motors.In this thesis,existing papers on the iron loss of the inverter-fed induction motors are reviewed.Then,proper definitions for the components of the iron loss in an induction motor are made;and the classical iron loss computation models and the typical PWM methods are analyzed thoroughly.Then,the influence of several PWM methods on the induction motor iron losses are investigated with Matlab Simulink and Maxwell finite element method(FEM)simulations.Using the simulation results,a novel empirical formula for predicting the iron loss with PWM power supply is given.Finally,to decrease the iron loss of the inverter-fed high-speed induction motor,a novel twin-coil dual-inverter topology and associated PWM methods are proposed.With the proposed system,the iron loss of the inverter-fed high-speed induction motor is reduced,and the efficiency is enhanced.Validations are made with the coupled electrical circuit and finite elements analysis.