Pulse width Modulation for Power Electronic Converters
IISc Bangalore Course , Prof. G. Narayanan
212 students enrolled
Overview of power electronic converters : Electronic switches - DC - DC converters - DC - AC voltage source inverter - Voltage source and current source inverters - Multilevel inverter - diode clamped inverter - Multilevel inverter - flying capacitor inverter.
Applications of voltage source converter : Applications of voltage source converter I (motor drives, active rectifiers) - Applications of voltage source converter II (reactive current and harmonic compensation).
Purpose of pulsewidth modulation (PWM) : Review of Fourier series - Harmonic voltages and their undesirable effects.
Pulsewidth modulation at low switching frequency : Low switching frequency operation of a VSI I (square wave operation, one switching angle per quarter) - Low switching frequency operation of a VSI II (Two switching angles per quarter) - Selective harmonic elimination and THD optimized PWM.
Triangle-comparison based PWM : Sine-triangle modulation - Third harmonic injection PWM (THIPWM) - Bus-clamping PWM
Space vector-based PWM : Concept of space vector - Conventional space vector PWM and bus-clamping PWM - A unified perspective of triangle-comparison and space vector based PWM - Advanced bus-clamping PWM.
Analysis of line current ripple : Transformation from stationary reference frame to synchronously revolving dq reference frame - Volt-second balance and instantaneous error voltage - Calculation of RMS line current ripple - Space vector-based hybrid PWM for reduced line current ripple.
Analysis of dc link current : Inverter state and dc link current - Average and RMS values of dc link current.
Analysis of torque ripple : Calculation of harmonic torques and RMS torque ripple - Hybrid PWM techniques to reduce ripple torque.
Inverter loss : Evaluation of conduction loss - Dependence of switching loss on power factor and modulation method - PWM techniques for reduced switching loss.
Effect of inverter dead-time : Effect of dead-time with continuous modulation - Effect of dead-time with discontinuous or bus-clamping PWM.
Overmodulation : Per-phase approach to overmodulation - Space vector approach to overmodulation - A perspective from the synchronously revolving d-q reference frame.
PWM for multilevel inverters : Extension of sine-triangle modulation to three-level inverters - Extension of conventional space vector modulation to three-level inverters - Analysis of line current ripple and torque ripple.
Lecture 27: Instantaneous and average dc link current in a voltage source inverter