Project 1
Answer---->>>>Buck Converter
Buck converter step down DC voltage. It consists of Inductor, Capacitor and two switches which are transistor and diode.Transistor(moseft or igbt based on application) is a switch that operates with on and off state. ON and OFF states get controlled by the Gate signal.
Vout = 30V
Power = 500W
If Vin = 40V
D= Vout /Vin= 30 /40 = 0.75;
If Vin = 50V
D= 0.6
IL= P/ Vout =300 /30 = 10A
v2= Rout /P =302/ 300 = 3Ω
Ripple I=0.1 X 10 = 1A
L= Vout /(1-D)= 30 /(1-0.75)
fs =4IL =50*1000*1 = 0.00015H
Cout = (1-D) /8Lf4(∆Vout/Vout )= 8.33*10-7 F
Vin L C
40 0.00015H 8.33*F
50 0.00024H 8.33*F
The simulation circuit shows the buck converter.
The inductor current has resulted as 10A.
On and OFF operation of a switch is with the frequency 50khz and is shown in below.
The Diode current and Mosfet current is shown below.
If the same buck converter parameters are modified as the
Vin = 400 to 500V
Output voltage = 300V
Power = 5KW
Below are the rating requirments for the inductor, capacitor and rersistor.
Input: Vin = 400V to 500V
Vout = 300V
Power =5000W
If Vin =400V
D: Vout /Vin =300/400 = 0.75;
If Vin = 500V
D= 0.6
IL =P /Vout= 5000 /300 =16.66 A
Rout=(Vout)2/ P= (300)2 /5000 = 18Ω
Ripple I=0.1 X 16.66 = 1.666A
L Vout (1-D) 300*(1-0.75) fs AIL 50*1000*1 = 0.0015H
Cout (1-D) AVout Vout = 8Lf = 8.33*10-6 F
Input: Vin = 20 to 30V; Vout = 40V; Power = 600W
If Vin = 20V
D: Vout 40 Vin 20 1-D and D = 0.5;
If Vin = 30V
D: Vout 40 Vin 30 1-D and D = 0.25;
R= v2 out P = 2.67
IL Vin (1-D) 2* R = = 29.96A
L= Vin fs 4IL 3.33 10-3 H
C
(D)
AVout
Rfs Vout
For input Voltage V = 30 V
IL Vin (1-D)2* R = = 14.98A
Simulation displays that the output voltage after the run simulation shows that the output voltage is reaching 40V.
Other resukts are as shown below.
The zoomed results of the BOOST converter are shiwn in the above results.
It shows the output voltage is 40V diode current and MOSFET current are showing that the switches are operating alternatively and PWM signal is switching onn the MOSFET into ON and Mosfet is OFF when PWM signal is OFF.
The above boost converter results if the input voltages are modified the results vary as shown below.
Matlab simulation file:
Boost Converter display is as shown below:
I_Diode, Mosfet current and PWM signals are shown below for the input voltage of 200V to 300V.
output voltage is expected as 400V.And the diode and current operates with different ON and OFF situations.
Diode current is ranging upto 20A and MOSFET current is ranging upti 25A.Where the PWM pulses shows the ON and OFF states of the MOSFET.
5.sepic converter:
SEPIC COnverter:
Sepic converter is the single Ended Primary inductor converter. This is a type of DC-DC converter that operates to allow the electrical output greater than, lessthan, or equal to the input.Output is controlled by the duty cycle of the switch.
Sepic Converter is a boost converter followed by the inverter Buck-Boost Converter.
Vin is 30V to 60V;
Vout is 45v
Power P =1
D/(1-D) = Vout/Vin
So D = 0.6
As there are two inductors in the circuit the inductor _1 L1 is at the voltage input of the circuit and another inverter is at the parallel end.
From the Calculations as per the instructor, the values of L and C are designed as