The performance analysis of dual-inverter three phase fed induction motor with open-end winding using various PWM schemes

Induction motor with scheme open end winding (OEW) has attract many attention in the recent time as a compromising alternative of multi-level inverter. The structure contains of simplicity in generating multi-level inverter and has potential ability to obtain a better quality output due to higher number of the available switching states and voltage vectors.' Based on the method to divide the voltage references, various Pulse Width Modulation (PWM) schemes for the dual-inverter fed induction motor with OEW have been discussed in this paper. The first one is developed by equally splitting the voltage references to two inverters and termed as Equal Reference Division Pulse Width Modulation (ERD PWM). In the second PWM scheme, the voltage references are devided according to moduation index (M). At M > 0.525, one inverter is modulated using maximum voltage reference while the other one inverter is modulated proportionaly according the change of voltage reference. The PWM scheme is named as Unequal Reference Division Pulse Width Modulation (URD PWM). In the third PWM scheme, the two inverters are modulated using different method, i.e one inverter is controlled in slow switching PWM and the second inverter are modulated using fast switching PWM. Hence the thirs PWM is named as Mixed Devider Switching (MDS) PWM scheme. The results shows that the MDS PWM provide the best voltage Total Harmonic Disortion (THD) performance among the three PWM schemes. Further the speed-torque acceleration shows that the dual-inverter fed structure is able to control the speed to reach the desired speed at t = 0.25 s. The speed is able to adjust when the load is apply at t = 0.4 s. The motor current THD and the mechanical torque reveal that the MDS PWM provide the best among three PWM schemes.