Inverters in Power Electronics And Drives: Practice MCQ Questions and Answers

2 practice sets · Page 1 of 1

Power Electronics And DrivesEasyPower ElectronicsInvertersSingle Phase Voltage Source Inverters

The THD of an inverter output waveform should be _________ to ensure proper operation of the load and to minimize electromagnetic interference.

Infinite

Equal

High

Very Low

Answer and explanation

Correct Answer: D — Very Low

THD measures harmonic distortion relative to the fundamental frequency. A very low THD means the output waveform closely resembles a pure sine wave, ensuring loads such as motors and transformers operate efficiently, minimizing EMI, and reducing thermal stress on components.

Power Electronics And DrivesEasyPower ElectronicsInverters

Which statement is true regarding the inverter?

The voltage waveform generated in a single phase system is unsymmetrical around the time axis and the odd harmonics are present in the resulting pulse width modulated waveform.

The voltage waveform generated in a single phase system is unsymmetrical around the time axis and the odd harmonics are absent in the resulting pulse width modulated waveform.

The voltage waveform generated in a single phase system is symmetrical around the time axis and the odd harmonics are absent in the resulting pulse width modulated waveform.

The voltage waveform generated in a single phase system is symmetrical around the time axis and the odd harmonics are present in the resulting pulse width modulated waveform.

Answer and explanation

Correct Answer: C — The voltage waveform generated in a single phase system is symmetrical around the time axis and the odd harmonics are absent in the resulting pulse width modulated waveform.

In a single-phase PWM inverter, the output voltage waveform is symmetrical around the time axis, ensuring consistent positive and negative cycles. Due to this symmetry, odd harmonics cancel out and are absent in the PWM waveform, resulting in an output that closely approximates a pure sine wave.

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Inverters in Power Electronics And Drives: Practice MCQ Questions and Answers