Control Theory Assignment | Online Assignment

Further Electrical and Electronic Systems (CSMM403)
Coursework 2020
Q1) 60%
A battery charger is shown below. It consists of a dc voltage source Vdc, half‐bridge power
electronics inverter, LCL filter. The output of the converter is connected to the battery with
voltage vu. The system parameters are shown below:
vdc  700v dc
1 L  1.2mH
2 L  30 H
C  60 F
200 uv  v dc
1 L
C
2 L
in v u v
1 i 2 i


2
dc v
2
dc v
c i Battery
Design a controller that controls the output current 2 i which is the current injected into the
battery. Follow the below design steps.
1) Derive the block diagram of the LCL filter showing in v as input, 2 i as output, u v as
disturbance.
2) Analyse the system stability if a single feedback loop of 2 i is used.
3) Design a stable controller. Consider using an extra feedback loop of i1 or ic.
4) Derive the closed loop transfer functions. To derive the closed loop transfer function
relating 𝑖􀬶 to 𝑖􀬶 ∗ set 𝑣􀯨 to zero in the block diagram. Similarly, to derive the closed
loop transfer function relating 𝑖􀬶 to 𝑣􀯨 set 𝑖􀬶 ∗ to zero in the block diagram.
5) Build a linear block diagram of the controller and the controlled plant into
Matlab/Simulink. By trial and error adjust the controller gain/gains to get a good
transient response with zero steady state error.
6) Build the complete system including the power electronic converter and your
designed controller using Matlab SimPowerSystem and present the results of
a) Inductor voltage
b) Inductor current
c) Capacitor current
d) Output current
Q2) 40%
a) For the control system shown below, design a compensator such that the unit
step response curve will exhibit a maximum overshoot of 30% or less and settling
time of 3 sec or less. Verify your design by Matlab results.
b) For the control system shown below, design a compensator such that the unit
step response curve will exhibit maximum overshoot of 60% or less and settling
time of 6 sec or less. Verify your design by Matlab results.