Lecture 9.1: Resonant Converter Analysis

We're finishing up the fundamental analysis of resonant converters. Specifically the resonant tank and soft switching.
0:00 - Intro and Recap
4:00 - Common Resonant Tanks
11:12 - Resonant Converter Model with tank
13:20 - Conversion Ratio
24:00 - Bode Plot Derivation - Algebra on Graph
28:40 - Input Impedance
39:30 - Transfer Function
42:35 - Inductive vs. Capacitive
45:00 - Q and Resistance
50:00 - Soft Switching
52:35 - Switching Below Resonance
59:45 - Switching Above Resonance
1:05:15 - Outro
Reference Textbook:
Fundamentals of Power Electronics - Erickson and Maksimovic

[@justingilmore1225]

OUTSTANDING EXPLANATION

[@evak7970]

Love ur videos!

[@marupuruvinodmarupuruvinod3181]

amazing lecture on resonant converters, thanks a lot sir

[@fayazbaig9345]

Very amazing lecture on resonant converters. I had a hard time understanding how the H(S) curves are being plotted, but this session made it very simple to comprehend. I would like to know why LLC resonant converter is the most diffused one compared to LCC resonant converter. Looking ahead to future sessions.

[@audiokees4045]

I did get when on resonance switching with LCC a very high Cs voltage of 3 kilovolts and amperage on startup because of output anti ripple capacitor, later dropping when output voltage is nominal value. I can clearly see a resistive action when do this, therefore I do set Fsw 0.7 to 0.85 x Fres amd use chip soft start.

[@rajasekhar2041]

excellent analysis. Just i want to ask one question Professor, 20log(Z2) is taken as 20log(Req) as both are like a kind of parallel?

[@mayurkumavat3640]

Hello sir, could you please tell us what is the difference between filters, snubbers and resonant converters?

[@jacobs7281]

Thank you for the the video @ 0.10 mentioned about previous video , if there is recording available will you please post a link

[@timmcrae3831]

The previous video is chronologically the one before this and can be found on the channel.

[@subhajitmahanta6974]

sir solve one electric vehicle question

[@shyamofmace]

At below resonance, when turn-off of switch occurs, how can the voltage across the switch rise? Because the anti parallel diode is conducting, the voltage will be clamped to 0.6 V or so.

[@timmcrae3831]

You're right, when the anti-parallel diode conducts, the FET voltage is clamped. Eventually, when the opposite pair of switches is turned on, those anti-parallel diodes will be reversed biased and the voltage across the FETs will then rise.
Maybe I don't understand where your question is coming from, but to clarify: The hard switching that occurs at Ts/2 is for switches Q2 and Q3 (including reverse recovery losses of the anti-parallel diodes).

[@shyamofmace]

@@timmcrae3831 thank you, its clear now.

[@audiokees4045]

Gan mosfets are a nice new way, no body diode anymore and much cleaner switching. What it does with zvs in resonance converters I do not now, maybe capacitance's are enough.,

[@akashkedia4618]

Hi Sir,
What is characteristic impedance, Ro ?

[@akashkedia4618]

Got it Sir, after watching the full video. Thanks a ton.