Basics of Power Electronics & Practical Guide with PSIM

Explain the resistance firing circuit for SCRs, using a variable resistor network to generate gate pulses and limit current with a potential divider, ensuring proper triggering.

Explore the resistance firing circuit part 2, where a potential divider across an ac supply drives the gate, and a diode clips negative cycles to regulate the firing angle alpha.

This lecture explains the resistance firing circuit and how a rectified sine voltage across the resistor, compared to the gate threshold set by the manufacturer, defines the firing angle alpha.

Explore the types of firing circuits and the evolution of rc firing circuits, including resistance firing and full‑wave rc firing with gate‑to‑cathode signaling.

Discover how a relaxation oscillator built with a unijunction transistor (UJT) can trigger a thyristor, including the UJT structure, its negative resistance region, and practical advantages and limitations.

Explore how a relaxation oscillator using a uni-junction transistor charges and discharges a capacitor to produce pulses that trigger a thyristor, with construction and practical gate pulse applications.

Explain how an rc firing circuit charges a capacitor to gate threshold and triggers at threshold, controlling the firing angle from 0 to 180 degrees via the time constant r×c.

Delve into the construction and operation of a unijunction transistor relaxation oscillator to trigger SCRs, detailing the charging of the timing capacitor, intrinsic standoff ratio, and the resulting trigger pulses.

Explore the operation of a UJT relaxation oscillator for triggering SCRs, detailing full-wave rectified supply, voltage division with series resistor R1, and AB voltage control.

Explore the UJT relaxation oscillator for SCR triggering, including full-wave rectified DC supply, zener stabilization, RC charge-discharge dynamics, and how firing angle is controlled by resistance.

Explore triggering of SCRs using a UJT relaxation oscillator and the RAM and pedestal triggering circuit, including ramp circuits, pedestal stabilization, and pulse behavior.

Explore protection strategies for thyristors (SCRs) in power electronics, covering internal and external overvoltage, overcurrent, thermal protection, and the use of metal oxide varistors to clamp surges.

Explore SCR protection including overcurrent and leakage protections, circuit breakers, fast-acting limiters, and heat management with heatsinks to control junction temperature and prevent failure.

Understand guard strategies for thyristor (SCR) gates against overvoltage and overcurrent. Use diodes, resistors, shielded or twisted cables, and snubbers to improve gate reliability and suppress noise.

Protect thyristors from high di/dt and dv/dt using snubber circuits and duty protection, with explanations of local hotspots and relevant SCR protection topologies.

Explore the principle of DC to DC choppers, focusing on the step-down (buck) converter, its switching devices, inductor energy, and freewheeling diode to produce variable output voltage from fixed input.

Explore the theory and PSIM experiment of a step-down chopper with a resistive load, analyzing input and output voltage, duty cycle effects, freewheeling diode, inductor, and MOSFET gate drive timing.

Explore the operation of a boost (step-up) chopper, showing how duty cycle controls the output voltage while an inductor, freewheeling diode, and load shape the circuit response.

Explore a PSIM-based experiment of a step-down chopper with a resistive load, configuring a stripped-down jumper, setting duty cycle, and analyzing input and output voltages.

explains the step-up dc-dc converter operation, detailing the inductor–diode–load circuit, energy storage during on/off intervals, and the input–output relationship with duty cycle.

Cover the theory and PSIM-based experiment of a step-up chopper with a resistive load, examining input and output voltages, duty cycle, and basic circuit elements.

Explore a step-up chopper experiment in PSIM with a resistive load, using voltage probes to compare input and output waveforms and analyze a 0–180 degree duty cycle.

Explore how to regulate chopper output voltage through duty cycle and time ratio control, comparing constant-frequency PWM with variable-frequency schemes.

Explore how chopper output voltage is controlled using variable frequency and duty-cycle strategies, contrasting constant-frequency pulse-width modulation with frequency modulation schemes.

The lecture compares frequency modulation, pulse rate modulation, and current limit control for chopper output voltage, noting duty-cycle limits and the use of two preset current limits to regulate output.

Explore the advantages and disadvantages of choppers, their dc voltage regulation and duty-cycle considerations, and compare step-down and step-up jumpers for efficient energy control.

Classify ac to dc converters, focusing on rectifiers, their types, and practical considerations in power electronics using PSIM.

Explore the classification of ac to dc converters, also known as rectifiers, in part 2, with practical guidance from the basics of power electronics and PSIM.

Explore the classification of AC to DC converters and rectifiers in power electronics, with practical PSIM insights and part 3 coverage.

Explore single-phase center-tapped transformer rectifiers, where two diodes form a full-wave uncontrolled rectifier with a resistive load, yielding a DC output of 2Vm/π.

Explore single-phase half-wave rectification using a silicon controlled rectifier, analyze firing angles and gate signals, and observe the pulsating dc output across an R-load.

Explore PSIM simulation of a half-wave controlled rectifier with an R load by building the circuit, setting a firing angle, and measuring input and output voltages to obtain average output.

Explore single-phase half-wave controlled rectification with an RL load, featuring firing angle alpha, gate triggering, and the transition between conduction and open-circuit intervals.

Explore the operation of a single-phase half-wave controlled rectifier with an inductive load, deriving average and rms output voltages and analyzing conduction and extinction angles.

Explore single-phase, fully controlled bridge rectifiers with an R-load, covering circuit operation, forward voltage conditions, and gate triggering at firing angle alpha.

Explore a single-phase fully controlled full-wave rectifier using four SCRs with an RL load. Learn firing angles, wave-rectification paths, and continuous current during positive and negative half cycles.

Explains a single-phase full-wave fully controlled bridge rectifier with an RL load, detailing firing angles, gate signals, and positive/negative half-cycle conduction.

Analyze a single-phase fully controlled bridge rectifier with an RL load, focusing on D1–D4 conduction, firing angle alpha, and inductance effects on output during positive and negative cycles.

Analyze single-phase, fully controlled bridge rectifiers with an rl-load and firing angles alpha. Examine gate signals, diode conduction, and output voltage across positive and negative half cycles, part three.

Analyze a single-phase fully controlled bridge rectifier with an RL load, evaluating output voltage and current for firing angles below, at, and above 90 degrees.

Learn about the single-phase center-tapped mid-point rectifier with an assisted resistive load, including firing angle control (alpha), rectification basics, and output voltage behavior.

Explore the mid-point converter with a resistive load, including primary and secondary windings and rectification to dc. Examine negative and positive half cycles and gating signals shaping the output voltage.

Learn how single-phase semi-converters use a two-thyristor, two-diode bridge to rectify ac to dc. Study symmetrical and asymmetrical half-controlled configurations with inductive loads and firing angle alpha.

Explore single phase semi-converters as a fully controlled ac-to-dc converter using semiconductors, analyzing conduction and output behavior for an inductive load across positive and negative cycles.

Examine the single-phase full with controlled ac to dc converter, known as semi converter, and analyze its output voltage and current, waveforms, and D1/D2 conduction during alpha intervals.

Explain symmetrical semi-converters with an RL load and PSIM simulation, derive the average output voltage formula as a function of firing angle alpha, and analyze the rectified waveforms.

Demonstrates an experiment with a symmetrical semi-converter using PSIM, featuring RL load, firing-angle control, rectification, and measuring average output voltage via simulation and calculations.

Explore the theory of asymmetrical semi-converters with RL load using PSIM, detailing firing angles and two-leg rectification. Derive and validate the output voltage for a 300-volt single-phase supply.

Demonstrate an asymmetrical semi-converter with inactive load in PSIM. Set firing angles for positive half-cycle rectification, and analyze input, output voltages and the average output.

Simulate a single-phase full-wave fully controlled rectifier with a resistor load in PSIM, applying a 45° firing angle to obtain about 169 V and 16.9 A average outputs.

Simulate a single-phase full-wave fully controlled bridge rectifier with an R load in psim, configuring sinusoidal input, firing angles, and measuring output voltage and current with probes and meters.

Explore a single-phase fully controlled rectifier with an RL load using PSIM, deriving output voltage and current, and analyzing firing angles, rectification and inverter operation.

This experiment presents a single-phase full-wave fully controlled rectifier with an inductive load using PSIM, detailing firing angles and measuring input and output voltages.

Explore a single-phase full-wave fully controlled rectifier with an inductive load using PSIM, adjusting firing angle to 90 degrees to study input–output behavior and average output voltage.

Explore single-phase half-wave ac voltage controllers with resistive loads, using silicon controlled rectifiers and diodes to vary output voltage by firing angle in positive and negative half cycles.

Explore how a single-phase ac to ac converter works as a voltage controller, using SCRs in a controlled bidirectional arrangement to vary output voltage via firing angle.

Explore a half-wave ac controller with an r-load using PSIM to vary firing angle and observe the input and output voltages in a single-phase circuit.

Explore a full-wave ac voltage controller with an R load in a single-phase circuit simulated in PSIM, adjusting firing angles at 50 Hz with a 300 V input.

Learn how full-wave ac voltage controllers regulate inductive loads using SCR-based converters, firing-angle control, and transformer components to adjust output voltage and current.

Explore a full-wave ac voltage controller with inductive load in PSIM, covering circuit setup, firing angle alpha, and analysis of input and output voltage waveforms.

Explore dc to ac inverters, converting dc to ac with required voltage and frequency, and classify them by input source, output waveform, and power electronic devices.

Dr. Martin explains how to build a half-bridge inverter with a resistive load, detailing essential components—dc supply, two switches, diodes, and feedback—using MOSFETs and SCRs to generate AC from DC.