Q.3) An ideal boost converter is required to have a constant output voltage of 12 V at 24 W load. The input voltage varies from 2.7 to 4.5 V (as in a battery cell). Select a switching frequency of 100 kHz. The value of the inductance in the boost converter is 1.0 µH. Determine: (a) The range of duty cycle that the converter will operate with, and (b) The minimum value of the output capacitance such that the pk-to-pk load voltage ripple is less than 2 %.

Calculate the rms value of the output voltage of an AC-AC converter with the following specifications. Vs—110*sqrt(2)*sin(wt), Alpha Pi/6

A buck-boost converter operates with an input battery. It converts +12 V to –12 V at apower level of about 75 W. the switching frequency is 120 kHz. The switches have200 ns switching time. The battery has an internal series resistance of 0.2  and seriesinductance of 200 nH. (a) What is the operating value of the duty ratio? What power is lost in the battery resistance? (b) Propose an interface structure to improve operation and decrease losses. What are the duty ratio and battery         resistance loss with your interface in place?

C'uk Converter Design A C'uk converter has an input of 12 V and is to have an output of - 24 V supplying a 60 W load. Select the duty ratio, the switching frequency, the inductor sizes such that the change in inductor currents is no more than 12 percent of the average inductor current, the output ripple voltage is no more than 1.5 percent, and the ripple voltage across C1 is no more than 3 percent.

18. A dc-dc converter is to be built with the following specifications: Allowed dc input voltage range: +8 V to +18 V +24 V Output average voltage: Output voltage ripple: ±0.06 V maximum at rated load 300 W, resistive ±250 mA maximum at rated load 100 kHz Rated load: Input current ripple: Switching frequency: Common ground between input and output. a. Draw a circuit which can perform this function. b. What is the necessary range of duty ratio for each switch? c. Find circuit part values (R, L, and C) which will meet the stated specifications.

4. A DC/DC step down converter is supplied by 96 V DC supply and produces average 24 V DC output. The switching frequency is 1 kHz, Al = 10 A, R=16 Ohm a. Draw equivalent circuit and obtain the duty cycle and the value of inductance. b. How do you reduce the voltage ripple below AV=5 V.

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