International Journal of Power Electronics and Drive System (IJPEDS) Vol. 11, No. 4, December 2020, pp. 1785~1798 ISSN: 2088-8694, DOI: 10.11591/ijpeds.v11.i4.pp1785-1798  1785 Journal homepage: http://ijpeds.iaescore.com Modulation index effect on inverter based induction motor drive Akhilesh Sharma 1 , Anandh N. 2 , Sarsing Gao 3 1,3 Electrical Engineering Department, North Eastern Regional Institute of Science & Technology, Nirjuli, Arunachal Pradesh, India 2 Department of Electrical and Electronics Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, India Article Info ABSTRACT Article history: Received Jan 23, 2020 Revised Apr 26, 2020 Accepted May 31, 2020 Due to a substantial increase in the use of inverter for numerous electrical appliances starting from domestics to industrial drives, an inverter may be directly connected to the power grid system. The dependency on an inverter has been increased over the years. Hence, the proper and efficient design of the inverter will lead to higher efficiency. One of the major challenges is the generation of suitable gate pulses for power switching devices, which in turn depends on the modulation index. The selection of proper modulation index will help in the production of the rated voltage. If the modulation index is less, the duration of on-time pulses will be less and hence, the device's conduction time is also less, thereby the output voltage of the inverter is reduced. A reduced voltage, when applied to an induction motor will have lower speed and even its performance will be sluggish. The speed of the motor improves when it is operated in a closed-loop for the same modulation index. This research paper tries to bring out the effect of modulation index on speed control of an induction motor based on an inverter for both open as well as closed-loop operation. The simulated results indicate that the modulation index in the vicinity to unity will provide rated voltage for the smooth operation of the motor. Keywords: Induction Motor Modulation Index Neural Network Space Vector PWM This is an open access article under the CC BY-SA license. Corresponding Author: Akhilesh Sharma, Electrical Engineering Department, North Eastern Regional Institute of Science & Technology, Nirjuli, Papum Pare, Arunachal Pradesh 791109, India. Email: as@nerist.ac.in 1. INTRODUCTION Frequent fault on the power system, unavailability of power to remote location and availability of solar energy at such locations have increased the utility of inverter, as they serve as a standby ac power supplies from a DC source [1] to meet the load demand. Even, inverters are applied for the industrial drive during shut down or power failure due to fault. Hence, the operation of inverter plays an important role in such applications. The inverter circuit consists of many switching devices. To turn on these devices, proper triggering pulses are essential. The duration of these pulses depends on the switching frequency and its modulation index (MI) [2-7]. MI selection becomes important provided the switching frequency is constant. With the advancement in the design of inverter, they are capable of providing the power needed for industrial drives. Mostly, these drives consist of induction motors (IM) because they have special features like simple, rugged in construction with minimum maintenance need, etc. Most importantly, they can operate