T1, 2023 – ELEC4614
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Hand-in Assignment 1
T1, 2023 – ELEC4614
22 February 2022
You are required to submit this hand-in assignment for ELEC4614. The mark from this assignment will contribute to 10% of your final class mark. You are expected to submit this hand-in assignment via the MOODLE ELEC4614 website (not the OpenLearning site) before 3pm on Friday week 4 of term. Late submissions will not be accepted. You must include a signed cover sheet declaring that the work submitted is your own work and this must be the first page of the assignment. The link for this cover sheet is found in the Assignment 1 section of the OpenLearning site.
Areas where students often lose marks:
- Not reading the question properly
- Not answering the question asked
- Not clearly showing their workings
- Not following the instructions in the question
- Not understanding the theory, or lectures
- etc
ASSIGNMENT 1 [worth 20 Marks and 10% of the final mark]
This assignment is designed to assist you in understanding datasheets for power electronic devices and identifying the important data and specifications.
During the lectures on power semiconductor devices we have discussed why MOSFETs are preferred for low voltage (<200V) applications and that IGBTs are preferred for higher voltage applications (>600V). We have also discussed that the Rds(on) of a MOSFET increases as the voltage rating increases and that the increase is nonlinear.
Using a power semiconductor device manufacturer LittelFuse’s catalogue:
https://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_power_semiconductors_ product_catalog.pdf.pdf
On page 48 of the catalogue there is a list of MOSFETs with voltage ratings from 100V to 300V. For each of the devices with voltage ratings [100V, 150V, 200V, 250V, 300V] and current rating of 120A, tabulate the Rds(on) and the conduction losses in the device assuming they operate at the current rating of the device and have a duty ratio of 0.5 (equal times spent in the ON and the OFF condition. Comment on whether Rds(on) increases with increased voltage blocking capability. [8 marks]
On the same page of the catalogue, select the 100V devices and tabulate the devices that have current ratings of [75A, 110A, 140A, 170A] and include in the table Rds,on, Qg the gate capacitance, trr, and Rthjc . What trends in these parameters can you note and what is the reason for their change? [8 marks]
Finally, on page 25, selecting a 1200V XPT IGBT how does the Vce and the RthJC change as the current rating of the IGBT increases? In 2-3 sentences explain why. [4 marks]
2023-03-09