Power Electronics MCQs (Part-7)

What does Power Factor Correction (PFC) aim to achieve in power electronics systems?

A To reduce system losses
B To match the voltage and current waveforms
C To increase the switching speed
D To increase the output voltage

Which of the following is the primary goal of harmonic analysis in power systems?

A To determine the phase angle of the current
B To analyze the effect of non-sinusoidal currents on power quality
C To measure the energy efficiency of the system
D To control the speed of electric motors

What is the primary function of Pulse Width Modulation (PWM) in power electronics?

A To reduce power factor
B To control the voltage or current delivered to the load
C To step up or step down the voltage
D To filter high-frequency noise

Which of the following is a key benefit of using PWM for motor control?

A Increased current ripple
B Smooth control of motor speed
C Decreased energy efficiency
D Increased harmonic distortion

What is the purpose of an active filter in power electronics?

A To step up the voltage
B To filter out high-frequency noise and harmonics
C To convert DC to AC
D To store energy

In renewable energy systems, why is an inverter used?

A To convert AC to DC
B To convert DC to AC for grid integration
C To store energy
D To regulate the output voltage

Which of the following factors is critical to improving energy efficiency in power electronics?

A Reducing switching losses
B Increasing the size of components
C Using higher voltage levels
D Reducing current ripple

Which device is commonly used for speed control of electric motors in industrial applications?

A Diode
B Thyristor
C MOSFET
D IGBT

What is the typical application of a DC-AC inverter in renewable energy systems?

A To step down the voltage for battery charging
B To convert DC to AC for grid synchronization
C To filter harmonics from the AC output
D To regulate the output voltage

Which of the following is the primary cause of harmonic distortion in power systems?

A Overloading of the transformer
B Non-linear loads such as rectifiers and power supplies
C Voltage spikes from switching
D High-frequency noise from the grid

What is the effect of improving the power factor in a power electronics system?

A Decreases the system’s efficiency
B Reduces losses and improves system efficiency
C Increases the amount of reactive power
D Reduces the system’s overall voltage

What is a primary consideration when designing electric drives for motor control?

A Increasing harmonic distortion
B Efficiency of the switching devices
C Maximizing voltage levels
D Reducing current flow to the motor

What is the role of an energy storage device like a capacitor or battery in power electronics systems?

A To increase current flow
B To store electrical energy for later use
C To step up voltage
D To reduce harmonics

Which of the following techniques is commonly used to mitigate the effects of harmonics in power systems?

A Increasing the system voltage
B Using filters to block harmonic frequencies
C Using higher frequency switching
D Reducing the system’s load capacity

What is the primary advantage of using MOSFETs in high-frequency switching applications?

A High power loss
B Low switching losses
C Slow switching speed
D High gate drive power requirement

What type of converter is typically used for voltage regulation in power supplies?

A Cycloconverter
B DC-DC converter
C Inverter
D Rectifier

Which component is commonly used for protecting a power electronics circuit from overvoltage conditions?

A Zener diode
B SCR
C Transformer
D Diode

What type of converter is used to change DC to a different level of DC voltage?

A Rectifier
B DC-DC converter
C Inverter
D Cycloconverter

What is the role of a filter in a power converter?

A To reduce harmonic distortion and smooth the output signal
B To step down the voltage
C To store energy
D To increase system voltage

Which device is used for frequency conversion in an AC circuit?

A Rectifier
B Cycloconverter
C Inverter
D DC-DC converter