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Pulse Width Modulation PDF

The document discusses various methods of pulse-width modulation that can be used for voltage control of inverters, including single-pulse-width modulation, multiple-pulse-width modulation, trapezoidal modulation, sinusoidal pulse-width modulation, staircase modulation, and stepped modulation. Multiple pulse-width modulation uses several pulses in each half cycle to reduce harmonics and filter size. Sinusoidal pulse-width modulation varies the width of each pulse proportionally to a sine wave. The disadvantages of pulse-width modulation include high switching stresses on devices from load current switching and electromagnetic interference from high switching rates.

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146 views7 pages

Pulse Width Modulation PDF

The document discusses various methods of pulse-width modulation that can be used for voltage control of inverters, including single-pulse-width modulation, multiple-pulse-width modulation, trapezoidal modulation, sinusoidal pulse-width modulation, staircase modulation, and stepped modulation. Multiple pulse-width modulation uses several pulses in each half cycle to reduce harmonics and filter size. Sinusoidal pulse-width modulation varies the width of each pulse proportionally to a sine wave. The disadvantages of pulse-width modulation include high switching stresses on devices from load current switching and electromagnetic interference from high switching rates.

Uploaded by

Khairul
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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Voltage control of inverters

single-pulse-width modulation
multiple-pulse-width modulation trapezoidal modulation
sinusoidal pulse-width staircase modulation
modulation stepped modulation
modified sinusoidal pulse-width harmonic injection modulation
modulation delta modulation
phase-displacement control

Mahmood Sunny, Asst. Prof., DEEE, UU DC-AC Converters April 9, 2020 2 / 22


Pulse-width modulation

Figure: multiple-pulse-width modulation

Mahmood Sunny, Asst. Prof., DEEE, UU DC-AC Converters April 9, 2020 3 / 22


Pulse-width modulation

Multiple pulse-width modulation


several pulses in each half cycle to reduce harmonic contents and to
increase harmonic frequencies to reduce size and cost of filter
reference signal frequency controls output frequency
carrier signal frequency controls number of pulses per half cycle
modulation index controls output voltage (M = Ar /Ac )

Mahmood Sunny, Asst. Prof., DEEE, UU DC-AC Converters April 9, 2020 4 / 22


Pulse-width modulation

Figure: sinusoidal pulse-width modulation

Mahmood Sunny, Asst. Prof., DEEE, UU DC-AC Converters April 9, 2020 5 / 22


Pulse-width modulation

Figure: sinusoidal pulse-width modulation

Mahmood Sunny, Asst. Prof., DEEE, UU DC-AC Converters April 9, 2020 6 / 22


Pulse-width modulation

Sinusoidal pulse-width modulation


Width of each pulse is varied in proportion to the amplitude of a sine
wave
reference signal frequency controls output frequency
peak amplitude of reference signal controls modulation index and
output voltage
output voltage vo = Vs (g1 − g4 )
bidirectional or unidirectional carrier signal can be used

Mahmood Sunny, Asst. Prof., DEEE, UU DC-AC Converters April 9, 2020 7 / 22


Disadvantages of pulse-width modulation

switching devices are turned on and off at the load current with a
high di/dt value
switches are subjected to high voltage stress
electromagnetic interference is produced due to high di/dt and dv/dt

Mahmood Sunny, Asst. Prof., DEEE, UU DC-AC Converters April 9, 2020 8 / 22

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