Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
__________ method is an internal method for controlling the inverter output voltage.
Series connection of inverters
Chopper method
Commutating capacitor
Pulse width modulation
Pulse width modulation
Pulse Width Modulation (PWM) is an internal control technique where the inverter's switching states are adjusted to control the output voltage magnitude and frequency. By varying the width of the output pulses, the average output voltage can be regulated without needing external components.
Pulse Width Modulation (PWM) is an internal control technique where the inverter's switching states are adjusted to control the output voltage magnitude and frequency. By varying the width of the output pulses, the average output voltage can be regulated without needing external components.
VrmsтАЛ=VsтАЛTDтАЛтАЛ тАФ RMS output voltage of a PWM inverter
VavgтАЛ=VsтАЛтЛЕD тАФ Average DC component
In PWM, the power semiconductor switches (IGBTs/MOSFETs) are turned on and off multiple times within a single half-cycle. By changing the duty cycle (the ratio of pulse width to pulse period), the fundamental component of the output voltage is controlled. This eliminates the need for bulky external voltage regulation circuitry.
PWM allows for simultaneous control of output voltage and frequency.
It significantly reduces lower-order harmonics, improving power quality.
Internal control means no external auxiliary components like choppers or tapped transformers are required.
The switching frequency of PWM is generally much higher than the fundamental output frequency.
Reduced harmonic distortion
Simplified power circuit
High efficiency due to switching control
Higher switching losses in devices
Requires complex control circuitry (microcontrollers/DSP)
Variable Frequency Drives (VFDs)
Uninterruptible Power Supplies (UPS)
Renewable energy grid-tie inverters
External methods for voltage control include using an AC voltage regulator or a DC-DC chopper before the inverter.
Option B (Chopper) is an external method usually placed between the DC source and the inverter bridge.
D is correct тАФ Pulse Width Modulation (PWM) is an internal control technique used to vary the output voltage by modulating the duration of the conducting state of the inverter switches.
Always distinguish between 'Internal Control' (performed by switching within the inverter) and 'External Control' (performed by modifying input DC or output AC via external components).