WorksheetsPE Quiz 4
Total questions: 20
Worksheet time: 10mins
In a single-phase voltage source inverter operating in 120° mode, each thyristor conducts for:
60°
90°
120°
180°
In 120° conduction mode of three-phase inverter, the number of switches conducting simultaneously is:
1
2
3
4
The frequency of the triangular carrier wave in SPWM should be:
Equal to reference frequency
Lower than reference frequency
Much higher than reference frequency
Half of reference frequency
Modified Sinusoidal PWM differs from conventional SPWM by:
Using square wave reference
Injecting third harmonic to reference
Using multiple carriers
Eliminating carrier wave
In Space Vector Modulation (SVM), the number of switching states possible in a three-phase inverter is:
6
8
12
16
In SVM, the zero vectors are:
V1 and V6
V0 and V7
V2 and V5
V3 and V4
The voltage space is divided into how many sectors in SVM?
3
4
6
8
The main advantage of SVM over SPWM is:
Simpler to implement
Better DC bus utilization and reduced harmonics
Lower cost
No switching losses
In induction heating applications, inverters typically operate at:
50-60 Hz
500 Hz - 1 kHz
High frequency (1 kHz - 1 MHz)
DC
What is the function of an inverter?
Charge the battery
Convert DC from battery to AC for load
Regulate input voltage
Filter harmonics
In single-phase AC voltage controllers with resistive load, the power factor is:
Leading
Lagging
Unity
Zero
The firing angle range in AC voltage controllers for continuous conduction is:
0° to 90°
0° to 180°
90° to 180°
0° to 360°
Power factor control in AC voltage controllers refers to:
Controlling input power factor
Maintaining constant power factor at all loads
Controlling output voltage while maintaining power factor
Eliminating reactive power
Multistage sequence control in AC voltage controllers is used to:
Increase voltage levels
Reduce harmonic distortion by switching multiple cycles
Control multiple loads
Improve efficiency
A single-phase to single-phase cycloconverter can produce output frequency:
Higher than input frequency
Equal to input frequency
Lower than input frequency (typically 1/3 of input)
The output frequency of a cycloconverter is:
Higher than input frequency
Equal to input frequency
Lower than input frequency (typically 1/3 of input)
Any frequency
The number of thyristors required for a single-phase to single-phase cycloconverter is:
2
4
6
8
The main disadvantage of cycloconverters is:
High cost
Poor input power factor and high harmonic content
Low efficiency
Complex cooling requirements
Matrix converters differ from cycloconverters by:
Having no intermediate DC link or energy storage
Using more switches
Operating at lower frequencies
Being single-phase only
AC voltage controllers are commonly used in welding applications to:
Convert AC to DC
Control welding current and heat input
Increase voltage
Generate high frequency
