Problem 2-1 (6 points) Consider the following periodic input current (i(t) or Iin ) waveform of a
power converter circuit (shown in the bottom figure). The input voltage of the power converter is:
Vin = 169.70 sin 2513t.
vin=169.70 Sin 2513t
1. The input current (i(t)) waveform has the same frequency as the voltage.
2. i(t) in the top figure is the same as iin the bottom figure.
Q1. (2 points): What is the THD of the input voltage?
Q2. (2 points): What is the RMS value of the input current?
Q3. (2 points): What is the overall power factor of the power converter?
Problem 2-2 (6 points): A non-ideal power semiconductor switch is used in a switching dc
power supply. The switch’s leakage current is negligible. This unique switch has voltage and
current waveforms as shown below.
(a) If the switch has a duty ratio of 0.4, what is the average conduction loss over a complete
(b) What is the maximum switching frequency at which the switch can operate if the total loss
(conduction + switching) is limited to 448 W?
Problem 2-3 (6 points): Consider the following battery charger circuit.
§ The primary side of the transformer is connected to 120V (RMS) 60 Hz system (THD =
§ The transformer has a turn ratio of 2:1, and this is an ideal transformer
§ The diode used in the circuit is ideal
§ The battery voltage is steady at 12V regardless of the state of charge.
§ The average charging current (iCh) is limited to 5A
Q1. Determine the conduction period of the diode (the diode will conduct between these two
angles, and you will need these results to answer Q2 and Q3)
Q2. Determine the value of R in order to limit the average charging current to 5A.
Q3. What is the power loss across R (think about the average and RMS charging current)
Problem 2-4 (6 points): Solve problem 3-3 from the text. Do it for only Fig 3-3 (a), (b) and (e)
Problem 2-5 (6 points): Solve problem 3-4 from the text. Do it for only Fig 3-3 (a), (b) and (e)
This material may consist of step-by-step explanations on how to solve a problem or examples of proper writing, including the use of citations, references, bibliographies, and formatting. This material is made available for the sole purpose of studying and learning - misuse is strictly forbidden.