A step-up chopper is supplied through a source of 200 V and operated at a duty cycle of 50%. Find the average output voltage of the chopper.
Chopper Output Voltage Calculation
A step-up chopper, also known as a boost chopper, is a power electronic converter that produces an output voltage greater than its input DC voltage. It achieves this voltage step-up by rapidly switching a semiconductor device (like a MOSFET or IGBT) to store energy in an inductor and then release it to the load at a higher voltage.
Step-Up Chopper Principle
The operation of a step-up chopper relies on the energy stored in an inductor. When the switch is ON, the inductor stores energy from the source. When the switch is OFF, the inductor's polarity reverses, and its stored energy adds to the source voltage, resulting in a higher output voltage across the load. The amount of voltage step-up is controlled by the duty cycle of the chopper.
Key Formula for Step-Up Chopper
The average output voltage (\(V_o\)) of a step-up chopper is determined by the input source voltage (\(V_s\)) and the duty cycle (\(\alpha\)). The formula for the average output voltage of a step-up chopper is:
\[V_o = \frac{V_s}{1 - \alpha}\]Where:
- \(V_o\) is the average output voltage
- \(V_s\) is the source voltage
- \(\alpha\) is the duty cycle (ratio of ON time to total switching period)
Given Parameters
From the problem statement, we have the following values:
- Source voltage (\(V_s\)) = 200 V
- Duty cycle (\(\alpha\)) = 50%
Detailed Step-by-Step Solution
To find the average output voltage of the step-up chopper, we will follow these steps:
- Convert Duty Cycle to Decimal: The duty cycle is given as a percentage, which needs to be converted into a decimal for use in the formula. \[\alpha = 50\% = \frac{50}{100} = 0.50\]
- Apply the Step-Up Chopper Formula: Substitute the given source voltage and the calculated decimal duty cycle into the average output voltage formula for a step-up chopper. \[V_o = \frac{V_s}{1 - \alpha}\] \[V_o = \frac{200}{1 - 0.50}\] \[V_o = \frac{200}{0.50}\]
- Calculate the Average Output Voltage: Perform the division to find the final output voltage. \[V_o = 400 \text{ V}\]
Final Result
Based on the calculations, the average output voltage of the step-up chopper is 400 V.
Important Questions from Choppers
Choppers are _______ converters.
A chopper is a -
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Chopper converts fixed d.c. input voltage to a controllable d.c. output voltage. The Chopper circuit require forced or load commutation to turn off the thyristors.
Reason R: The Chopper circuits are dependent upon the type of commutation and also on the direction of power flow.
In the light of the above statements, choose the most appropriate answer from the options given below
A load commutated chopper fed d.c. drive uses 100 V d.c. supply. The maximum chopper frequency is 5 kHz. The value of maximum load current is 100 A. The commutating capacitance will be :
In a lossless buck converter, an average power of 20 W to a load with a regulated 12 V output, while operating at a duty cycle of 0.8 with continuous inductor current. Following data is given :
(a) The average value of input voltage is given by 15 V
(b) The average value of input voltage is 16 V
(c) The average value of input current is 4/3 A
(d) The average value of input current is 3/4 AWhich is correct out of the following ?
