ELEC9711 Assignment 1- due Friday, week 4, 3pm
John Fletcher
3 August 2023
You are required to submit this assignment for ELEC9711. The mark from this assignment will contribute to 10% of
your final class mark. You are expected to submit this hand-in assignment using a PDF file via the Assignment 1 link
on the ELEC9711 Moodle page before 3 pm on the Friday of week 4 T3 2023. 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: it is available on the OpenLearning site alongside this assignment.

Q1:

The circuit above is a 4th order dc-dc converter with a buck-boost transfer function and an inverted output voltage, Vo.
The design of the circuit must satisfy the following specifications:
Vo = 50 V Io = 0.5-2.5 A
Vd = 40-60 V fsw = 100 kHz (PWM)
ΔIL1 and ΔIL2 should be 5% of the dc current
in the inductor at maximum load.
Capacitor voltage ripple should be 0.5% at
rated load and minimum input voltage
(a) Calculate the maximum and minimum modulation index required, Dmax and Dmin, given the stated potential
variation in the input voltage.
[1 mark]
(b) Determine the inductances of the circuit (L1, L2) showing that the chosen values of the circuit parameters will
satisfy the specification. [Typically, you should sketch the waveforms over one switching cycle to evidence
meeting the specification.]
[3 marks]
(c) Determine the capacitances of the circuit (C1, C) showing that the chosen values of the circuit parameters will
satisfy the specification. [Typically, you should sketch the waveforms over one switching cycle to evidence
meeting the specification.]
[3 marks]
(d) Calculate the highest peak voltage and peak current in each circuit element including the switch, T, and diode,
D, for the parameter values that you calculated in (a-c).
[3 marks]
You must show any workings and state assumptions made at any stage of the calculations.