22-Elec-B8 Power Electronics and Drives
Worked solutions to 13 past sittings (2013–2019), 77 questions. Pick a sitting, or start from a topic below.
- December 2019
- December 2018
- May 2018
- December 2017
- May 2017
- December 2016
- May 2016
- December 2015
- December 2014
- May 2014
- December 2013
- May 2013
- Undated paper
Topics across the sittings
Topics that come up in more than one sitting, taken from the headings of our worked solutions. A topic counts once per sitting.
- Current-Source-Inverter-Fed Induction Motor (5 sittings): May 2018 Q5 · May 2017 Q5 · December 2016 Q5 · December 2015 Q5 · May 2014 Q5
- Basic Chopper (4 sittings): December 2019 Q5 · December 2017 Q4 · May 2014 Q2 · December 2013 Q4
- Bridge-Fed Separately Excited DC Motor (3 sittings): May 2017 Q6 · December 2016 Q6 · May 2013 Q6
- Current-Fed (3 sittings): May 2017 Q3 · December 2016 Q3 · December 2013 Q3
- Smoothing Reactors (3 sittings): December 2015 Q3 · December 2013 Q4 · May 2013 Q4
- Voltage-Fed Inverters (3 sittings): May 2017 Q3 · December 2016 Q3 · December 2013 Q3
- Constant Volts-per-Hertz Induction Motor Drive (2 sittings): December 2018 Q5 · December 2014 Q5
- Converters (2 sittings): May 2018 Q1 · December 2017 Q1
- Drives (2 sittings): May 2018 Q1 · December 2017 Q1
- Half-Wave Controlled Rectifier (2 sittings): December 2018 Q2 · May 2014 Q4
- Harmonic Content (2 sittings): December 2014 Q3 · May 2014 Q3
- Harmonic Sources (2 sittings): December 2015 Q2 · May 2013 Q2
- Load Currents (2 sittings): December 2014 Q3 · May 2014 Q3
- SCR Characteristics (2 sittings): May 2016 Q1 · May 2014 Q1
- SCR turn-off time (2 sittings): May 2017 Q2 · December 2016 Q2
Questions by sitting
December 2019
- Question 1: Radial distribution feeder with two loads
- Question 2: Line current of a mixed three-phase load
- Question 3: Thyristor operating regions and gate behaviour
- Question 4: Single-phase a.c. voltage controller feeding a motor
- Question 5: Basic chopper — completing the design table
December 2018
- Question 1: A.C. Voltage Controller Feeding an Induction Motor
- Question 2: SCR Turn-Off and a Half-Wave Controlled Rectifier
- Question 3: Basic Chopper Feeding an R–L Load with Back EMF
- Question 4: Harmonics of a Single-Pulse-Modulated Inverter
- Question 5: Constant Volts-per-Hertz Induction Motor Drive
- Question 6: Bridge-Fed Separately Excited D.C. Drive
May 2018
- Question 1: Part 1 — twenty short-answer items on devices, converters and drives
- Question 2: controlled half-wave rectifier feeding a dc motor armature
- Question 3: single-phase ac voltage controller feeding a motor
- Question 4: basic dc chopper with an R–L load
- Question 5: current-source-inverter-fed induction motor
- Question 6: three-phase bridge feeding a separately excited dc motor
December 2017
- Question 1: Part 1 — twenty short-answer items on devices, converters and drives
- Question 2: half-wave controlled rectifier with an R-L load
- Question 3: single-phase a.c. voltage controller feeding a motor
- Question 4: basic chopper, completing the load table
- Question 5: current-source-inverter drive, torque and slip
- Question 6: bridge-fed separately excited d.c. motor
May 2017
- Question 1: Snubbers, and an a.c. voltage controller driving an inductive motor
- Question 2: SCR turn-off time, and a half-wave controlled rectifier with an R-L load
- Question 3: Current-fed versus voltage-fed inverters, and single-pulse modulation harmonics
- Question 4: Series smoothing reactors, and a basic chopper with an R-L load
- Question 5: Under-frequency operation, and a current-source-inverter-fed induction motor
- Question 6: Types of dc drive, and a bridge-fed separately excited dc motor
December 2016
- Question 1: Snubbers, and a Full-Wave AC Voltage Controller Feeding a Motor
- Question 2: SCR Turn-Off Time, and a Half-Wave Controlled Rectifier with an Inductive Load
- Question 3: Current-Fed vs Voltage-Fed Inverters, and Single-Pulse-Modulation Harmonics
- Question 4: Series Smoothing Reactors, and a Basic Chopper Feeding an R–L Load
- Question 5: Under-Frequency Operation, and a Current-Source-Inverter-Fed Induction Motor
- Question 6: Types of DC Drive, and a Bridge-Fed Separately Excited DC Motor
May 2016
- Question 1: SCR Characteristics and a Single-Phase A.C. Voltage Controller
- Question 2: Basic Chopper with an R–L–Back-EMF Load
- Question 3: Harmonics in a Single-Pulse-Modulation Inverter
- Question 4: Inverter Auxiliaries and Chopper Ripple with a Changed Load Resistance
- Question 5: High-Frequency PWM Drives and Constant-Volts-per-Hertz Breakdown Torque
- Question 6: Three-Phase Bridge Speed Control of a Separately Excited D.C. Motor
December 2015
- Question 1: SCR Static Characteristic and A.C. Voltage Controller Delay Angles
- Question 2: Harmonic Sources and a Full-Wave Controlled Rectifier Feeding a Back E.M.F.
- Question 3: Smoothing Reactors and a Basic Step-Down Chopper
- Question 4: Single-Pulse-Modulated Inverter Feeding a Motor with Power-Factor Correction
- Question 5: High-Frequency PWM Drawbacks and a Current-Source-Inverter-Fed Induction Motor
- Question 6: Three-Phase Bridge Converter Driving a Separately Excited D.C. Motor
December 2014
- Question 1: A.C. Voltage Controller Feeding an Inductive Motor Load
- Question 2: Controlled Half-Wave Rectifier with a Back-EMF Load
- Question 3: Single-Pulse-Modulation Inverter — Harmonic Content and Load Currents
- Question 4: Basic DC Chopper — Ripple Ratio and Time-Domain Currents
- Question 5: Constant Volts-per-Hertz Induction Motor Drive
- Question 6: Three-Phase Bridge-Fed Separately Excited DC Drive
May 2014
- Question 1: SCR Characteristic and a Full-Wave a.c. Voltage Controller
- Question 2: Basic Chopper — Critical On-Time and Peak Load Current
- Question 3: Single-Pulse-Modulated Bridge Inverter — Harmonic Content and Load Currents
- Question 4: Half-Wave Controlled Rectifier — Sensitivity of the D.C. Output
- Question 5: Current-Source-Inverter-Fed Induction Motor
- Question 6: Three-Phase Bridge-Fed Separately Excited D.C. Drive
December 2013
- Question 1: Multiple-Pulse versus Sinusoidal PWM, and a Two-Pulse Uniform-PWM Inverter
- Question 2: Synchronous-Machine Reactances, Capability Curves, and Salient-Pole Power Transfer
- Question 3: Current-Fed versus Voltage-Fed Inverters, and Harmonic Analysis of a Single-Pulse-Modulated Bridge
- Question 4: Clamping Capacitors, Smoothing Reactors, and a Basic Chopper
- Question 5: Side Effects of High-Frequency PWM Drives, and Constant Volts-per-Hertz Operation
- Question 6: Converter-Fed Separately Excited DC Drive
May 2013
- Question 1: Armature Reaction and Full-Load Generated Voltage of a Round-Rotor Synchronous Generator
- Question 2: Harmonic Sources, and a Controlled Rectifier Feeding a Back-EMF Load
- Question 3: Harmonic Generation, Mitigation, and Single-Pulse Modulation of a Bridge Inverter
- Question 4: Smoothing Reactors and Shunt Capacitors, and a Basic Chopper with an R-L Load
- Question 5: Effects of High-Frequency PWM, and Constant Volts-per-Hertz Control of an Induction Motor
- Question 6: DC Drive Speed Control, and a Bridge-Fed Separately Excited DC Motor
Undated paper
- Question 1: Part 1-A — Short-Answer Theory
- Question 2: Part 1-B — Multiple Choice with Explanations
- Question 3: Controlled Half-Wave Rectifier with an R–L Load
- Question 4: Single-Phase Full-Wave a.c. Voltage Controller
- Question 5: Step-Down Chopper Table
- Question 6: Three-Phase Bridge Drive for a Separately Excited d.c. Motor