A voltage commutated chopper has the following parameters: Vs = 220 V. Commutation circuit: L = 20 μH and C = 50 μF. Find the effective on period for a constant load current of 80 A and Ton = 800 μsecs

To find the effective on period (Te) for a voltage commutated chopper, we start by using the energy balance principle and the given parameters.

Given:

– Supply Voltage (Vs) = 220 V

– Commutation Inductance (L) = 20 μH = 20 × 10^-6 H

– Commutation Capacitance (C) = 50 μF = 50 × 10^-6 F

– Load Current (I) = 80 A

– On period (Ton) = 800 μs = 800 × 10^-6 s

The effective on period can generally be calculated using the formula:

[

Te = frac{L cdot I}{Vs} + Ton

]

Substituting in the known values:

1. Calculate ( frac{L cdot I}{Vs} ):

[

frac{L cdot I}{Vs} = frac{(20 times 10^{-6} , H) cdot (80 , A)}{220 , V}

]

[

= frac{1.6 times 10^{-3}}{220} = 7.27 times 10^{-6} , s

]

2. Now, add this to the Ton:

[

Te = (7.27 times 10^{-6} , s) + (800 times