Project 1
Project-1
Choose any three topologies and develop the models in Simulink.
The project design report should include the following:
1- A Design report to show the reasoning behind your choices of inductance and capacitance levels in your design.
2- The full schematics of your converter including gate drivers, PWM chips, RC circuits, current sensors, voltage sensors, etc…
3- A complete simulation file including all the necessary waveforms and justifying all the chosen components sizing (you have to show the system ability to track the output voltage at different dynamic conditions).
4- The full specs for all the needed components in your circuit.
Solution:
In the above Buck CCM (40 to 50 V and 400 to 500V), Boost CCM (20 - 30V and 200-300V) and Sepic CCM (30-60V, 300 - 600V) are chosen.
Totally 6 topologies are designed.
Buck Converter: Buck Converter in Continuous Conduction mode.
Buck converter does DC-DC conversion.
Buck converter steps down the DC voltage. It consists of Inductor, Capacitor, and two switches which are Transistor and diode. Transistor (MOSFET or IGBT based on the application) is a switch that operates with On and Off states. ON and Off states of switch get controlled by the Gate signal.
This is the buck converter used to convert the DC to DC with step-down operation.
|
Vin |
L |
C |
|
40 |
0.00015H |
8.33* F |
|
50 |
0.00024H |
8.33* F |
The simulation circuit shows the buck converter.
The results of the simulation are as below.
It shows that the output voltage is 30V and the Capacitor voltage is the same as the output voltage.
The Inductor current has resulted as 10A.
On and off operation of the switch is with the frequency 50Khz and it is as shown below.
The Diode current and MOSFET currents are as shown below.
If the same buck converter parameters are modified as the
Vin = 400 to 500V;
Output voltage = 300V and
Power = 3KW
Below are the rating requirements for the inductor, Capacitor and Resistor. –
|
Vin |
L |
C |
|
400 |
0.0015H |
8.33* F |
|
500 |
0.0024H |
8.33* F |
MATLAB Simulation Circuit is as shown below:
Below are the responses of PWM, current in Diode and MOSFET current.
Below are the waveforms which tells that the MOSFET is ON and Off with the PWM signal. Diode is on for a period of time and MOSFET is ON in other period which is shown in the below graphs.
Inductor and Capacitor values are considered in such a way that the L and C values are high. As the input voltage range is from 40 to 50 and 400 to 500 in another Buck converter.
As per the different input values, the inductor and capacitor values are designed accordingly.
BOOST Converter_CCM:
Boost Converter:
The boost converter is the Step-up DC-DC converter. In the Boost DC-DC converter, the Output capacitor is the one that filters the pulsating current and allows DC current to flow through the output.
In continuous conduction mode, the inductor current flows continuously during the operation of the converter. The two semiconductor switches in operation are diode and Mosfet which operate with the PWM pulses. MOSFET is a switch whose gate pulses are given by the PWM pulse generator based on the Duty required to the switch.
It is considered that the frequency is considered as 30 kHz.
The schematic of Boost converter is as shown below.
The Mathematical expressions and calculations in desgning the required Inductor and Capacitor values.
Simulink file of BOOST Converter:
After the simulation is compiled, the simulation file is as shown below.
Simulation displays that the output voltage after the run simulation shows that the output voltage is reaching 40V
Other results are as shown below.
The zoomed results of the BOOST converter are shown in the above results.
It shows that Output voltage is 40V, Diode current and MOSFET current are showing that the switches are operating alternatively and PWM signal is switching on the MOSFET into ON state when the PWM signal is 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 as shown below for the Input voltage of 200V to 300 V.
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 upto 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 is greater than, less than, or Equal to the input. Output is controlled by the duty cycle of the control switch.
SEPIC converter is a boost converter followed by the inverter Buck-Boost converter.
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
Below are the output waveforms of the Circuit
Output voltage is varying between 41 to 42 v.
