Virtual Labs

a: Reduce the total harmonic distortion with modest filtering b: Increase the life of the batteries c: Minimize the load on the DC side d: Reduce low order harmonics and increase high order harmonics

A 3-phase grid-connected voltage source converter with DC link voltage of 1000 V is switched using sinusoidal Pulse Width Modulation (PWM) technique. If the rid phase current is 10 A and the 3-phase complex power supplied by the converter is given by (-4000 - j3000) VA, then the modulation index used in sinusoidal PWM is _________ (round off to two decimal places)?

a: Ma = 0.47 b: Ma = 0.72 c: Ma = 0.56 d: Ma = 0.95

Six MOSFETS connected in a bridge configuration (having no other power device) MUST be operated as Voltage Source Inverter (VSI)″. This statement is:

a: True, because being majority carrier devices. MOSFETs are voltage driven b: False, because it can be operated as both as Current Source Inverter (CSI) or a Voltage Source Inverter (VSI) c: True, because MOSFETs have inherently anti-parallel diodes d: False, because MOSFETs can be operated as excellent constant current sources in the saturation region

What does the modulation index value of 0 represent in SPWM?

a: The inverter is at full output voltage b: The reference waveform is not compared with the carrier waveform c: The inverter is OFF d: The inverter is at half output voltage

What is the primary reason for using SPWM in a grid-tied inverter?

a: To reduce the number of switches in the inverter b: To synchronize the inverter with the utility grid frequency c: To achieve higher efficiency in power conversion d: To generate a higher output voltage

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