Project 1 - Loss calculation for a DC/DC converter-MATLAB
Aim: Design of boost converter, and calculating the loss of different components including power switching device and deriving efficiency of boost converter. This is applicable in power supply industry, electric vehicles etc where DC-DC converter is required to boost the voltage from DC source.
Theory:
Boost Converters sometimes, also known as step-up choppers are the type of chopper circuits that provides such an output voltage that is more than the supplied input voltage. In the case of boost converters, the dc to dc conversion takes place in a way that the circuit provides a high magnitude of output voltage than the magnitude of the supply input.
It is given the name ‘boost’ because the obtained output voltage is higher than the input voltage.
Circuit Diagram of Boost Converter:
Design Steps:
Assume
Vin = 25V Vout = 50V , P = 125W. Frequency(Switching) = 50Khz (In this Project MOSFET is used).
Duty cycle D = 1-Vin/Vout = 1- (25/50) = 0.5
Iout = 125/50 = 2.5 A
Selection of Resistor, Inductor and Capacitor
L = D(1-D)^2/2*F = 20 milli Henry.
C = 400 micro-farad.
R = 50/2.5 = 20 ohms.
Simulink Model:
Plot of Output Voltage , Diode Current and Voltage, MOSFET Current and Voltage
Calculation of Losses:
1) Conduction Losses = Im^2 X Rds(on) X D = 0.13005.
2) Diode Losses = Vf X Iout X (1-D) = 5.094.
Efficiency of the converter = (Pout/Pin) = 1-(125/125.80) = 92.38.
Conclusion : Design of DC-DC boost converter was acheived according to design. Losses and efficiency was calculated.