Lecture 2: Analysis Methods and Rectifiers

[@lumpyfishgravy]

I trained in the late 1980s and we didn't get this level of *applied* engineering - mostly endless screeds of theory. What I use day to day is what I picked up and taught myself. And understand: I started work before The Internet. If there wasn't a book in the library, you didn't know it. I am loving this Playlist.

[@fabio.1]

👍👍

[@ttc2chan]

Me too😅

[@wthornton7346]

You took the words right out of my mouth!

[@veganath]

As much as i loved the 80's, freedom, privacy, music, near zero racism; education was orders of magnitude more difficult to source. Definitely looking forward to the day of AI directed private tutors....we're almost there

[@lasttrimestr49califos89]

Early 70s for me, so I totally get it😊

[@ervivekchoubey]

Being an electrical engineer, it is refreshing to watch these lectures and an absolute gem helping me to fill the knowledge gaps that remain due to time constraints while taking the classes and exams. ❤

[@karolakkolo123]

Perfectly put, with the time constraints and exams sucking all time you could otherwise use to make projects and learn other useful stuff

[@jrfutube2013]

How does pulse width modulation work in a variable frequency drive that controls a variable water flow motor/pump system?

[@alfonsocastellanosbalderas9842]

Thank you so much for sharing. Being an communications and electronics engineer, I am loving this video series.

[@user-co6ww2cm9k]

Loving the ghost of a previous lecture on state machines in the chalkboard! It takes me right back to class!

[@ProgrammingwithRabih]

Thank you very much for sharing such an interesting subject. It is the best power electronics course.

[@glenmerwyn5195]

Thank you for these lectures. I can't travel to a university (I'm geographically isolated) and need to study; I'm already a Mech eng, trying to study Electrical eng. Thanks (I live in NZ)

[@mohamedbenrekia2211]

So informative.. the teacher is so good..

[@suleyman9847]

i am so happy to be able to watch these informative lectures, thx for sharing us.

[@SeniorScriptKitty]

i really appreciate the fact that this guy is using child style chalk

[@BazieleSaah]

This whole lecture went over my head, but for some reason I watched it through

[@realrenifix]

😂

[@VolleyballFamilyAndFriends]

Wow. Second lesson felt like a brain masher and this is just the fundamentals. This is a quick recap from someone very new to all of this. The behavior or output of voltage and currents tells you what is happening inside a circuit if we know the inputs. It’s helpful to simplify switch states with assumptions and check for violations to known rules. This principle builds on the Inductor and Capacitor characteristics of a Periodic Steady State circuit. Inductors in a PSS have an average Voltage of zero and Capacitors in PSS have an average Current of zero. As you analyze the circuit behavior at different points you can predict the expected Voltage and Current and compare the real behavior to your understanding. Checking for violations of Capacitors or Inductors could point out in correct assumptions about switch states. There are circuit simulators that help diagram these ideas out and check the outputs as well like LTspice.

[@Treepox]

In my mind... 21:40. If Id is positive, the Vd is zero. That been said with an ideal diode. I think Vd is mixed up with Vo (Voltage over the resistor. Pleased to see reactions on my vision on this.

[@maxiandaur8509]

That's probably a little mistake

[@RobertKennedyPersonal]

At 41:43 it's not completely clear what needs fixing. Vx has a discontinuity but it isn't clear why that's a problem because Vx isn't the voltage seen by the load. It seems like the inductor still protects the load from the ugly source-side voltage behavior. It would seem clearer to me if the problem statement here were accompanied by a plot of the load voltage and a clear statement of what problem needs to be addressed from that perspective. Or more broadly, a clearer statement of what the problem is, whether it has to do with the voltage seen at the load or not.

[@karolakkolo123]

There are many implied problems with it. First of all, it reduces your average voltage at the output unnecessarily. More importantly, because you can never precisely predict the *actual* value of L, it will decrease the output by an amount that isn't fully predictable. Another problem is that sharp changes in state like that will produce a ton of unwanted electromagnetic emissions from the circuit because of the high frequency content before the filter (this wastes some power too btw). Perhaps there are other problems I didn't think of as well

[@pratyushmundra861]

From what I can tell, the average of Vx = average Vout (through KVL with Vx, VL, and Vout - since average inductor voltage = 0). So if Vx has a discontinuity or some negative values (voltage waveform goes below 0 here), then the average output would be reduced as @karolakkolo123 mentioned in their reply. My question to you is what you meant by "it seems like the inductor still protects the load from the ugly source-side voltage behavior"? Are you saying that the negative voltage values are not seen at the load? I'm uncertain there.

[@Firebird-XD]

Two things are there to be considered 1. When d1 goes off really it would mean infinite rate of change of current in inductor which would violate physical laws of nature and induce infinite voltage across itself. 2. The (ideal) circuit would hypothetically try to do that but as soon as the voltage gets higher than the negative voltage of the source d1 would start conducting. Conducting d1 in negative half cycle is something that we don't want that's why we put d2 to give it another path. In real world a large portion of the power circuit failures happens due to this.

[@byronwatkins2565]

At 21:00, you drew the load voltage rather than the diode voltage. When Vin>0 the diode is shorted and Vd=I(0)=0. When Vin

[@hueywallop2461]

Excellent lecture, thanks. But why doesn't MIT use OBS (or similar software) to allow simultaneous display of the speaker and the projections in the video?

[@MalyBa-ig2gi]

I am loving this shows ❤

[@mboykin6047]

Wake up camera person. Show the projected illustration at the end.

[@jamescollier3]

They went on to film TED talks

[@ohsnapfit2096]

I think it just tracks humans..

[@empty_set_]

@@ohsnapfit2096 No ,they switched on the first example and then didn't on the rest.

[@bentpen2805]

Guess I gotta download LT Spice now

[@adrienferreira4666]

I watch Yale lectures and they never film the screen as well. Usually it’s for copyright purposes. There’s even disclaimers stating that some materials are protected and can’t be displayed. The university can pay authors to project their work in the classroom to the students, but don’t have the right to distribute it on KZbin.

[@ovieoyegwa6153]

studying what's happening behind the hood in electrical/Electronics engineering. Thanks for the insight.

[@ruellerz]

Is it worth having a switch that can make multiple pulses to reduce the severity or is the inductor and capacitor flawless and doesn't need this assistance?

[@rafalklepinski7372]

Good, but feels like we missed something prof. Perreault was showing on the projector near the end..

[@therApist69]

It's paywalled : )

[@fabio.1]

​@@therApist69is there an online paid version of the course?

[@therApist69]

@@fabio.1yes but it’s well known to be hard to get in and costs quite a bit… might require a loan

[@fabio.1]

@@therApist69 👍

[@ayanahmed202]

You can download LTspice for free and simulate prof. Perreault's circuit. You can see everything you need to build the circuit at 48:36.

[@Ben_Dover753]

Much gratitude for this lecture playlist.

[@egertondidikallay9449]

Wonderful lecture ! Sadly we didn't get to see the simulations at the end. The Camera was too focused on the instructor.

[@kikifaqih_]

thanks so much mit, thanks too for the subtiltle❤

[@tidin_tss]

very quickly and very briefly

[@raisingjakestudios1371]

Your pointing out of the inductance in the wall power source raises a question: What is the impedance of the Power Grid given there can be hundreds of miles of wire from generating station to home electrical outlet? More specifically, how many "grid tied" solar power converters can be attached to this grid before it becomes unstable?

[@TexasElectrician77]

I am an electrician, not an electrical engineer (a little less math and a lot more hard work) but can say the impedance is quite low on the transmission lines because power is transferred over long distances at low current (Amps-I ) and very high voltage (Volts-E). Even from a neighborhood substation, the voltage will typically be 12,470 (3 wire Delta) at several hundred amps and stepping down to single phase 240 Volt for residential, 480Y/277V for commercial applications.

[@randydiffenderfer7793]

loving the availablility of these courses, as a retired quantum chemist, can see how the people who get their hands dirty do their stuff! also loving the "carbon copy" -- wonder how many students know where *that* came from? :D :D :D

[@evertnijhof7202]

Why is it that the addition of the second diode does not make this a full wave rectifier?

[@FooclesAutoRelay]

i love this

[@Alexis-vg4pc]

Thanks for sharing

[@alimovahedi7714]

In the first lecture you mention the reason for a linear regulator is due to Po/Pin but you did not use the same technique to describe the efficiency of the second technic, please.

[@mechadense]

5:00 start with new material

[@brucebuckeye]

ELI THE ICE MAN in action!

[@kayhanince]

ELI on ICE :)

[@lasttrimestr49califos89]

That one I know, lol

[@rich4239]

great series I am a noob and am confused at about 38 minutes the supply looks like a dc voltage but I think he is talking about AC...am I confused or is it just an oops by the prof

[@jnnewman90]

He is talking about AC at that time. The symbol for the source that he drew on the board is for DC, so it was his mistake. Everyone likely knew what he was talking about because he labeled the source as Vssin(wt) which implies that it is AC (sinusoidal).

[@myronboone84]

50:40 to 50:50 fault, default.

[@SeanyKash8]

Greatly appreciated~

[@campbellmorrison8540]

I wish I could go to MIT and really attend these lectures.

[@jamescollier3]

maybe a smaller school where you can ask a question, and not be on TV

[@campbellmorrison8540]

@@jamescollier3 Yes true, I really mean any University with these sort of courses and lecturers. Im now 70 and have done my dash unfortunately.

[@DHAVALPATEL-bp6hv]

@@campbellmorrison8540 no, you are not done, just keep moving .....

[@Jptoutant]

I dont exactly get this ideal diode, why is it ON at 0V? isnt it at 2V more or less , or the only thing to consider in his explanation is infinite current capability at ON state.. the saturation point can be moved around

[@harishbharadwajp3600]

If it's 2V more or less, how is it an ideal diode? An ideal diode should not have any voltage drop across it

[@karolakkolo123]

Ideal diode model makes initial analysis easier. Real physical diodes obviously have a voltage drop and for typical current values the "on voltage" will be listed in the datasheet. You can modify analysis to account for that by having a voltage source instead of a short when the diode is on, etc. If you want to be even more exact, you can use the exponential diode equations and use some kind of iterative approach by guessing an initial voltage value and updating the state of other elements, which will generate a new voltage guess etc, but usually that's more work than necessary, and at that point you could as well just simulate it on the computer...

[@gungagalunga9040]

could someone tell me the prerequisite course to this module?

[@mitocw]

Prerequisites: 6.2500 Nanoelectronics and Computing Systems For more info, visit the course on MIT OpenCourseWare at: ocw.mit.edu/courses/6-622-power-electronics-spring-2023/ Best wishes on your studies!

[@louistiticaramel6848]

I would assume MIT 6.002 Circuits and Electronics would be a good start to get the basics

[@gungagalunga9040]

@louistiticaramel6848 that's what I thought. An A1 high school education then lol.

[@louistiticaramel6848]

@@gungagalunga9040 depends on the country you did high school in I suppose, I personnaly had 0 electronic, electrical courses in high school not even kirchhoff's law

[@gungagalunga9040]

@louistiticaramel6848 thanks. I'm on lecture 15 of 6.002. Amazing course!

[@johnpearcey]

Irritated that you didn't show his final graph where he moved along and zoomed in to the steady state operation to show the average inductor current and its value.

[@amarissimus29]

I always forget about vD. And it always gets me. Pay attention kids, it's no fun.

[@Tomty369]

Rewatch from 33:40

[@saultube44]

That's incorrect to assume that in average an inductor and capacitor will do nothing, if the current varies, and/or the voltage, they'll generate a reaction. he should have said it referring to Direct steady current and voltage

[@jackevans2386]

Why has he not taken into account the 2 diodes' voltage drops of at least 0.6V each ?

[@josephthapa529]

It's an ideal diode assumption

[@misfitfarmandhomestead3057]

He's teaching theory in ideal conditions

[@tylerdurden9614]

what about lecture 3?

[@mitocw]

kzbin.info/www/bejne/iqHGZGx4q5iMgJo&pp=gAQBiAQB

[@ErixTrochez-b2e]

Son un arsertijo entre dos puerta se vuelven x

[@QamruddinKhanlove]

CAN POSSIBLE TO CHANGED AUDIIO TO HINDI OR ANOTHER LANGUAGE ALSO

[@ervivekchoubey]

Click the captions button and select auto-translate to Hindi.

[@dahappychappy]

Maybe we should simulate it in LT Spice. To see for ourselves.

[@denverbraughler3948]

MIT needs to standardize the titles of their videos. “Lecture 1” is a thoughtless name. The title needs course ID, year, lecture number, course name, and topic.

[@SakhiGuma687]

Imagine being so entitled that the most prestigious technical college in the world posts their class lectures for free and you complain about how they format their video titles.

[@tharun410]

​@@SakhiGuma687😂😂😂😂

[@bobross6228]

They do put some of that info in the description, but yeah a cursory title glance might not be so helpful

[@ervivekchoubey]

Exactly 😂 ​@@SakhiGuma687

[@WondererWandering]

Brooo how much entitled are you.... Also you can get the whole course in a structured way on their website. If you please follow the link in the description

[@ErixTrochez-b2e]

, es e s terminación po ase bale el sero

[@anssiluukkonen3715]

Cameraman was filming just teacher when he should have shown the audience the computer screen in last few minutes of this video.

[@ErixTrochez-b2e]

Es con kien dise pas o ira

[@dominiquejones8831]

There we are. I'm late. Sorry

[@kennethcfogarty]

Poor camera …

[@philorkill]

He's to clever for me. I would have asked a ton of "dumb" questions.

[@ErixTrochez-b2e]

V 12 vivo Jesus 5

[@jan-pcro]

nice projection, i guess? 😂

[@veganath]

Please camera person keep the focus view on the content not the container(lecturer), the content is more important to the end goal of education than the container....

[@sattarpc]

Maybe I don't know but this diode state assumption discussion should be short and simple.

[@Danmaster01]

I was thinking that. He made a half wave rectifier sound like an intel processor

[@donmoore7785]

He is developing a method, using ideal diodes as an example. I like this approach.

[@senkrouf]

@@donmoore7785 the problem is that your predictions are bad, and you will try to build buck boost converter and fail miserably and wonder, why it blew up if I did the math correctly?

[@ervivekchoubey]

In high frequency power electronic converter​ of any kind, there are hundred other things that you need to take care of and you can't depend on math for them. For example, the generated Electromagnetic Interference from high switching which may interfere with other components or circuits and may cause problems or a ground fault or device thermal runaway. Only real projects can help us understand things. However we need to keep those things aside to focus on the working circuit to get the concept. @@senkrouf

[@07sanjeewakaru]

That's a general method for solving many diode system..

[@mckone9]

Camermannnnnnn

[@neuroplush7657]

It's an automatic motion-tracking camera, it's doing its best.

[@tidin_tss]

все очень кратко и очень быстро

[@sdfasd8853]

Have you seen the video application for people who want to get to MIT? They already knew that. Seriously they are wasting money.

[@CutoutClips]

This is the second lecture of the course. It's important to establish a baseline of understanding before moving to more advanced topics.

[@FreedomIsNotGoingToBeFree]

Should MIT use something from this century on the wall? I mean it is kind of scary how he is trying to hand draw things when you could have a huge screen with animated perfect examples... (which are reusable, re-viewable and asymmetric (eg. you can spend hours making them instead of minutes)).

[@benjaminrich9396]

The mic picks up the chalk scraping on the board in a way I find awful. I love these lectures but that scraping noise is killing me. Please buy some whiteboards!