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(6TH SEMESTER) POWER ELECTRONICS (3-1-0) MODULE-I (10 HOURS) Thyristors, Static V-I Characteristics of SCR, TRIAC, GTO & IGBT, Turn-On & Turn-OFF Mechanism of SCR, Gate Turnoff Thyristor (GTO) .Power BJTs . Power MOSFETs Insulated Gate Bipolar Transistors (IGBTs) - Basic Structure and VI Characteristics. Static, dynamic and thermal characteristics. Protection, cooling and mounting techniques. Series and Parallel operation of devices. Triggering and basics of driver circuits. Different types of commutation schemes: Natural and Forced commutation. MODULE-II (10 HOURS) 1-Phase Half & Full Wave Controlled Rectifier with various kinds of loads (R, R-L-E (motor)). Midpoint and Bridge type converters. Half Controlled and Fully Controlled Bridge circuits, different waveforms, Input Line Current Harmonics, Power factor, current distortion and displacement factorsInverter Mode of Operation. Continuous and discontinuous modes, Effect of source inductance assuming constant load current. Effect of freewheeling diode. Three phase bridge converters for different types of load with constant load current, different waveforms. 180 and 120 degree operations. MODULE-III (10 HOURS) DC-DC Converters: Classification of types of choppers, One, Two and Four quadrant operations, Step up and down choppers, Analysis of Type-A chopper, Single-and two quadrant operation with DC motor load. AC-AC Converters: Single-phase mid-point and bridge types of step-up and step-down Cycloconverters. Single phase AC Voltage regulators and its basic analysis. MODULE-IV (10 HOURS) Single-phase Half and Full bridge Inverter, Pulse Width Modulated (PWM) technique for voltage control, SPWM Technique 1-phase inverters, Auxiliary Commutated (Mc-Murray) and Complementary Commutated (Mc-Murray Bedford) Inverters, Three-phase Voltage Source Bridge type of Inverters. (120 and 180 Degree conduction modes), Current Source Inverter. Applications: UPS, SMPS, Induction Heating, Electronic Ballast, AC/DC drives speed control.
MODULE - 1
POWER ELECTRONICS The control of electric motor drives requires control of electric power. Power electronics have eased the concept of power control. Power electronics signifies the word power electronics and control or we can say the electronic that deal with power equipment for power control. Main power source Ref signal Control Circuit Digital Circuit Power Electronic circuit Load Feedback Signal Power electronics based on the switching of power semiconductor devices. With the development of power semiconductor technology, the power handling capabilities and switching speed of power devices have been improved tremendously. Power Semiconductor Devices The first SCR was developed in late 1957. Power semiconductor devices are broadly categorized into 3 types: 1. Power diodes 2. Transistors 3. Thyristors (600V,4500A) (10KV,300A,30MW) Thyristor is a four layer three junction pnpn semiconductor switching device. It has 3 terminals these are anode, cathode and gate. SCRs are solid state device, so they are compact, possess high reliability and have low loss.