Design of controller based economic single phase to three phase converter shaping for low cost AC motor

Project Title

Design of controller based economic single phase to three phase converter shaping for low cost AC motor

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

Various electrical equipments require 3ø voltage supply. While small workshops & rural areas don’t prefer the installation of 3ø voltage supply due to high cost. This project is based on high speed switching converter & H-bridge inverter consists on N-channel MOSFET. Each MOSFET conducts for 180º & gating signals of each phase are advanced by 120º. In this way 1ø to 3ø voltage converter will be implemented. Moreover to meet demand of industry, VFD method & SPWM will be implemented to control speed of induction motor. Process of VFD is divided into two stages, AC to DC converter & DC to AC converter. First, 1ø AC voltage of 220V is converted into DC voltage using 1ø rectifier. After rectifier power goes to capacitors which convert pulsating DC into pure DC & deliver power to inverter section. Inverter contains MOSFETS that deliver power to induction motor. Controller is used for automatic switching of transistor. As in industry, it’s a complex problem to control VAR demand of 3ø induction motor which makes power factor more lagging. Ultimately, industry has to pay penalty to utility power company for its increasing lagging loads. This project offers 1ø inverter which will reduce power bills & improve system operating characteristics by reducing excessive voltage drops.

Project Objectives

The objective of this project is to design more inductive modalities and to evaluate those modalities. Project will really helpful in understanding the vast applications and use of power electronics at small level industries. We will get the knowledge of controller, inverter circuits, the driving techniques and capability of various switching devices.The main objective is to design a circuit utilizing the modern power electronics that will help various industrial process to run economically by saving energy, and this is a better way to do but by controlling the speed and torque of electrical drives that are essential part of every industry.

Project Implementation Method

Our system consists of two parts, first is single phase Bridge converter and second is three phase inverter.In first part single phase supply is converted into dc supply by using the power diodes at this state we convert the single phase supply into pulsating dc supply. For getting a pure dc supply we pass this dc supply into filter capacitor which converts this pulsating dc supply into pure dc supply and this dc supply is now provided to the drain of the power MOSFETs. To drive the gates of the power MOSFET we generate the PWM through microcontroller. This PWM (signal) is given to the gate of the power MOSFET through Opto isolator and gate driver IC.  In order to change the frequency of the system we use a variable resister. When we change the value of the resister microcontroller sense the desired command and change the frequency of the PWM and this PWM change the switching speed of the power MOSFET and by changing the speed of switching device the system frequency will be change according to the PWM frequency.The technique which we are using in our project is variable frequency drive method we know that frequency is directly interrelated to the speed of the motor. In other words, the higher the frequency, the higher the speed. If an application does not require an electric motor to run at full speed, the VFD can be used to ramp down the frequency and voltage to meet the requirements of the electric motor's load. As the applications motor speed requirements change, the VFD can simply turn up or down the motor speed to meet the speed requirement.

Benefits of the Project

Small industries; three phase installation is costly so voltage converter using single phase supply is beneficial and cheap.

Rural areas;three phase supply is not available in rural areas so single phase to three phase voltage converters is the solution for three phase electrical appliances.

Domestic areas;only single-phase supply is given for domestic use so voltage converter is much better for efficient performance.

Technical Details of Final Deliverable

Variable frequency drive provides us with both quality and economy. These features have made industrialists to switch to variable frequency drives. VFD provides speed control by maintaining constant torque. Therefore applications that require maintaining constant torque all the times are being switched to VFD. In our project we are tried to design an economical but efficient drive. This project will be used for speed control of medium sized motors. We know that the motors seldom operates at full load and mostly operates at less than full load so our design will be used in these situations providing economy and quality. We are using sinusoidal PWM in our project so the output waveform closely replicates the Sine wave, hence loads that need pure sine wave for their operation will be connected to the VFD. Besides due to sinusoidal nature the losses are reduced considerably.

Final Deliverable of the Project HW/SW integrated systemCore Industry ManufacturingOther IndustriesCore Technology Shared EconomyOther TechnologiesSustainable Development Goals Industry, Innovation and Infrastructure, Sustainable Cities and Communities, Responsible Consumption and ProductionRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	44946
opto coupler	Equipment	1	7000	7000
gate driver	Equipment	1	3000	3000
vero board	Equipment	5	400	2000
wooden board	Equipment	3	200	600
three phase induction motor	Equipment	1	8000	8000
step down transformer	Equipment	1	1000	1000
connecting cables	Equipment	20	100	2000
resistances	Equipment	8	80	640
diodes	Equipment	5	300	1500
single phase supply	Equipment	1	2000	2000
ICs	Equipment	3	150	450
transisters	Equipment	8	100	800
other small components	Equipment	12	413	4956
printing	Miscellaneous	3	3000	9000
photocopy	Miscellaneous	10	100	1000
arduino	Equipment	5	200	1000