International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 03 Issue: 05 | May-2016 www.irjet.net p-ISSN: 2395-0072 © 2016, IRJET | Impact Factor value: 4.45 | ISO 9001:2008 Certified Journal | Page 488 Single Phase to Three Phase MOSFET based Inverter Prof.R.R.Bhambare 1 , Prof.S.R.Kale 2 1 Associate Professor, Dept. of E&TC Engineering, SVIT Chincholi, Nasik, Maharashtra, India 2 Assistant Professor, Dept. of E&TC Engineering, SVIT Chincholi, Nasik, Maharashtra, India ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - Most of the induction motors required in industries today are working on three-phase source of alternating voltage. Three Phase A.C. supplies are not available for all the time, particularly in Rural Area. So a new scheme of Single Phase to Three Phase Inverter using MOSFET is proposed. A PWM technique is used to have a variable frequency A.C. Induction Motors. It also gives a variable speed control which deals with considerable savings in Energy and reduces cost of Electricity. Use of dedicated pulse generator (Microcontroller) IC HEF 4752 made by PHILLIPS for PWM generation and MOSFET IRF 840 is used for switching purpose to enhances the performance of the inverter. It generates six pulses required for three phase supply. The phase angle is programmed to 120 degree. The output of opto isolator is given to Darlington pair of transistors for amplification of current and voltage. A case study of kitchen ventilation system in a hotel shows that it can save energy up to 18%. Thus system can become more useful in today’s problem of energy crisis. Key Words: Frequency controlled induction motor drive P.W.M. inverter concepts 1.INTRODUCTION 1.1 Need for single Phase to Three Phase Inverter Nowadays electric supply is one of the basic needs but because of surrounding environmental conditions and practical limitations the generation of electricity is insufficient hence to fulfill the electricity requirement load shedding is executed, but it is not satisfying the complete requirement so inverter is used to obtain ac supply from a battery. In industries three phase appliances are frequently used due to their advantages over single phase power supply. If we go to have a three phase inverter which is available in the market, cost factor comes in to the picture. So we have made an attempt made to have DzSingle Phase to Three Phase MOSFET Based Inverterdz, which can save money up to great extent. This paper makes an attempt to demonstrate a variable frequency control of three phase induction motor using PWM technique, to control the speed of a three phase induction motor.[1] We aim to design and implement a variable frequency drive for three phase induction motor using PWM control technique for a three phase MOSFET based Inverter 1.2 Principle of Operation 1) To vary motor speed, we vary stator supply frequency Ǯfǯ because 2) Synchronous Speed = Ns = 120f / P. Where P = no. of poles of Induction Motor To achieve maximum torque we need to keep air gap flux constant .This is done by keeping the voltage to frequency ratio constant i.e. Vs / f = constant 1.3 Frequency controlled induction motor drive This method involves changing synchronous speed by changing frequency of a.c. supply to induction motor to cause speed variation, as the true speed of the motor is very close to synchronous speed. Either voltage source inverters or current source inverters may be used. 2. P.W.M. INVERTER CONCEPTS PWM is the method is used for switching devices to produce the effect of continuously changing analog signals. This PWM conversion has a very high electrical efficiency. In controlling either a 3 phase synchronous motor or a 3phase induction motor, it is required to receive a perfectly sinusoidal current waveform in motor windings, with relative phase displacements of 120⁰. The generation of sine wave power via a linear amplifier system is having low efficiency, up to 64%. If without using linear circuitry, fast electronic switching devices are preferred, and then the efficiency becomes greater than 95%, as per the characteristics of the semiconductor power switch.[2] Modulation of the duty ratio decides shape of Load current waveform. If the duty ratio is changing in time, then the current in an inductive load has nature of a sine wave at the modulation frequency, carrying ripple frequency .The IC HEF4752V for the A.C. motor control uses this particular method. The 1 kHz technique using SCR is highly useful for shaft output powers of more than a few kW.[3] However, using MOSFETS with switching times less than 1 µsec, the carrier frequency increases to the 20 kHz or more.[5] To avoid any D.C. in motor, and hence to avoid parasitic torque, a digital waveform generation technique should be used. As regards to micro-processor /micro-computer implementation ,the waveform is stored as a Ǯlook-upǯ table of numbers corresponding to the sine wave .To generate the 3 phases, this can be read such that the correct 120ᵒ phase relationship is maintained. The numbers from the table