Boost Converter Operating Principle
The working of the Boost converter can be explained in two modes of operation :
- Switch is ON and the Diode is OFF
- Switch is OFF and Diode is ON
Switch is ON and the Diode is OFF
During this mode of operation in a boost converter, the circuit will transfer energy from the input source to the output of the load. When the switch, typically a MOSFET, is turned on, the input voltage charges the inductor, which causes it to store energy in the form of a magnetic field. During this time the output capacitor will supply power to the load to maintain a stable output voltage. The capacitor will get charged during this time since it cannot discharge through the reversed baised diode. The switch plays a important role in controlling the current flow through the circuit and switching on the regulation of the output voltage through signals. Efficient regulation ensures that the boost converter can maintain a constant output voltage despite variations or changes in the input voltage which contributes performance and its reliability.
Hence this working mode makes the boost converter efficiency in stepping up voltage levels. By effectively transferring of energy from the input source to the output load it minimizes power losses and checks that there is a continuous and proper power supply. Stability and reliability are very important which requires proper voltage regulation and transient response to store dynamic load changes. By understanding this mode of operation we come to know the role of boost converter in various applications from battery powered devices to renewable energy systems where maintaining proper voltage levels is very important for optimal performance.
Change in current([Tex]\Delta Il[/Tex])
When the switch is on the inductor is charged due to the input voltage. The change in current through the inductor during this phase can be derived using the relationship between voltage and current and inductance :
[Tex]V=L.di/dt[/Tex]
Rearranging the above equation we can write as :
[Tex]\Delta Il=V.dt/L[/Tex]
when switch is on the voltage across the inductor is equal to input voltage hence we can write V as :
[Tex]V = Vin[/Tex]
The change in time dt when switch is on the duty cycle is multiplied by the switching period can be written as :
[Tex]dt = D . T[/Tex]
L = inductance of inductor
Substituting these values into the equation :
[Tex]\Delta Il = Vin*D*T/L [/Tex]
change in current ([Tex]\Delta Il[/Tex]) through the circuit is
[Tex]\Delta Il = Vin*D*T/L [/Tex]
[Tex]\Delta Il = [/Tex][Tex]2V*0.71*10\mu s/10\mu H[/Tex]
[Tex]\Delta Il=1.4A[/Tex]
Where :
Vin is the input voltage = 2V
D is the duty cycle of the switch ([Tex]D=Vout/Vin+Vout[/Tex]) = 0.71
T is the period of the switching cycle([Tex]T=1/F[/Tex]) = [Tex]10\mu s[/Tex]
L is the inductance of the inductor = [Tex]10\mu H[/Tex]
Switch is OFF and Diode is ON
During this mode of boost converter operation the input is off as the switch is turned off. In this state the inductor was storing energy before and now it will serve as an energy source. As there will be no magnetic field present, it will start inducing a voltage in the opposite direction, effectively boosting the output voltage. This induced voltage will allow energy to flow through the diode and into the output capacitor and the load which ensures a stable output voltage and a continuous supply of power to the load. This phase is very important for maintaining stable operation of boost converter ensuring that a smooth power supply even when there is no input source is available.
Hence this operational mode shows us the ability of boost converter to efficiently manage stored energy into the inductor and maintain a constant output voltage. The boost converter makes sure that a stable and reliable power supply to many applications which includes such as battery-powered devices and renewable energy systems. Understanding this mode shows us the mechanisms behind the boost converter functionality and its role in giving stable voltage levels.
In this mode the inductor will discharge its stored energy from the output load and this output voltage is applied across the inductor. This change in current through the inductor in this mode is derived using the same relationship between voltage and current and inductance
[Tex]V=L.di/dt[/Tex]
V is the voltage across the inductor
L is the inductance of the inductor
[Tex]di/dt[/Tex] is the rate of change of current through the inductor
rearranging the above equation we can write as :
[Tex]\Delta Il=V.dt/L[/Tex]
where dt is change in time when switch is on the voltage across the inductor is equal to the input voltage (Vin) and when switch is off the voltage across the inductor is equal to the output voltage (Vout)
so V can be expressed as :
[Tex]V = Vout – Vin[/Tex]
also change is time dt is equal to switching period multiplied by duty cycle complement (1 – D) so we can write dt as
[Tex]dt = (1-D).T[/Tex]
L = inductance of inductor
Substituting these values into the equation :
[Tex]\Delta Il=(Vout−Vin)⋅(1−D)⋅T/L[/Tex]
change in current ([Tex]\Delta Il[/Tex]) through the circuit is
[Tex]\Delta Il=(Vout−Vin)⋅(1−D)⋅T/L [/Tex]
[Tex]\Delta Il= 3V*0.29*10\mu s/10\mu H[/Tex]
[Tex]\Delta Il=0.87V*10\mu s/10\mu H[/Tex]
[Tex]\Delta Il=0.87A[/Tex]
where
Vin is the input voltage = 2V
Vout is output voltage = 5V
D is the duty cycle of the switch ([Tex]D=Vout/Vin+Vout[/Tex])= 0.71
T is the period of the switching cycle([Tex]T=1/F[/Tex]) = [Tex]10\mu s[/Tex]
L is the inductance of the inductor = [Tex]10\mu H[/Tex]
Boost Converter Operating Principle
In the world of electrical engineering power conversion plays a very important role in efficiently managing energy flow across various electronic systems. Among the types of conversion techniques, the boost converter plays a very important role in voltage regulation. It is one of the simplest types of switch mode converter With its ability to step up DC voltage levels, it finds extensive useful in diverse applications ranging from portable electronics to renewable energy systems.
Table of Content
- Boost Converter
- Working
- Waveform Representation
- Application
- Advantages
- Disadvantages