Effect of Phase Lead Compensator on Phase and Gain margins 1

[anklebreaker]

I was just wondering what was the general effect on phase and gain margins when a phase lead compensator was is added to a system.

 

[xnuke]

In general, stability margins are increased.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
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[anklebreaker]

@xnuke

Thank you for your reply. But could you please explain a bit why that happens

 

[xnuke]

As you probably know, the closer the phase angle is to -180° at the frequency when the gain is at 0 dB (the gain crossover frequency), the smaller the phase margin. Lead compensators, with a low frequency zero and a high frequency pole, have the zero frequency selected below the gain crossover frequency to add positive phase angle at the gain crossover frequency, thereby increasing the phase margin.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[anklebreaker]

@xnuke

Ohh.. I get it. Thanks a lot. I understand now