Final Exam 2017S, EEE360 Energy System and Power Electronics
Please write your name on each answer sheet.
(10 points for each question)
Problem 1. DC machine
1. Principle of the dc generator
(1) what generates the magnetic filed? Is it a dc field or ac field? Why the field is needed?
(2) Why the brush is needed?
(3) Describe “how and why the electricity is generated in the rotor winding”?
(4) What is the equivalent circuit of dc generator?
(5) What is related to the value of magnetic flux?
(6) What is the induced voltage related to?
(7) What is the relationship between velocity and angular frequency?
2. Principle of the dc motor
(1) How the magnetic field is generated?
(2) How the rotor rotates?
(3) What is the equivalent circuit for the dc motor?
(4) What is the relationship between the supply dc voltage and the induced voltage?
(5) How many types of excitation the dc motor has and what are they?
Problem 2. Power Electronics
1. Devices
(1) How many types of devices are used in power electronics and what are they?
(2) Which are fully controlled device? which are half-controlled? which are non-controllable?
(3) Please sort the three devices by their current rating: thyristor, IGBT, MOSFET.
(4) How many conditions needs to be satisfied to make a thyristor turned off and what are they?
(5) Is the gate voltage of IGBT a high voltage such as 1000V or above?
(6) What are the typical voltage rating for the IGBT？
2. Circuit
(1)Please draw the circuit of single phase rectifier, three phase rectifier, single phase inverter,
three phase inverter, dc-dc boost converter, dc-dc buck converter.
(2) Please explain in text how the inverter works
3. Modulation
(1) Please describe the principle of the Sinusoidal-Pulse-Width-Modulation principle? Which
circuit is this used on?
(2) Please describe the principle of the Pulse-Width-Modulation principle? Which circuit is this
used on?
Problem 3. Electricity Generation
1. How many types of electricity generations U.S. has?
2. Fossil Power Plant
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(1) In the steam generation flow diagram above, where the gas or oil or coal get mixed with the
air?
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(2)
(3)
(4)
(5)
(6)
(7)
(8)
Where the steam is generated?
What does superheater do and what does Reheater do?
Why there is high-pressure turbine and low-pressure turbine?
How the steam be cooled?
What device they used to filter the waste and absorb the SO2?
What is the function of cooling tower?
Explain the operating principle of a steam turbine.
3. Combustion turbine
(1)
(2)
(3)
(4)
What is driving the gas turbine?
How the generated be pushed to rotate?
What is the benefits of gas turbine compared to steam turbine? (tips: size? Dynamic?)?
what is the drawback of the steam turbine?
4. Nuclear reactor power plant
(1) How many water loops the pressurized water reactor nuclear power plant has and what are
they?
(2) Why the primary loop needs a high pressure?
(3) How the turbine is driven?
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(4) How the generator is driven?
(5) What does the feedwater pump do?
(6) What does the condense do?
5. Hydropower plants
(1)
(2)
(3)
(4)
How many types of hydropower plants is in U.S.?
Explain the principle of the hydropower plant.
What is a typical value for the poles of the hydro-generator?
What is the power of hydropower plant related to?
6. Wind generation
Describe the basic principle of the wind turbine generation.
7. Solar generation
Describe the basic principle of the solar generation.
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