How does AC (smart) charging actually work? PWM explained!

There are several AC home chargers that can either be straightforward or smart. The latter ones take your excess solar production into account, for example, or can be regulated via external signals. But how exactly does it do that? And how does it communicate that to the car?
For AC charging there is a protocol called PWM (Pulse Width Modulation) and in this video I do a deep dive into that protocol and what it all means.
#PWM #charger #smart
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[@eubikedude]

"Neutral" rather than "Neuter" in English. Another 👍 video, thanks.

[@stereo92]

Great video!! Good explanation. Thanks.

[@filipequeiroz651]

That's very simple and useful, thanks for your disposal and time to share

[@slavric]

This is a simple and useful explanation of the protocol. Thanks for sharing.

[@StevenPeeters]

You are welcome

[@realulli]

I found it very interesting! Thanks for the video! 🙂

[@StevenPeeters]

Glad you like it

[@nivaldospindola]

Thank you from Brazil, Great Explanation

[@eddyfontaineyoutu100]

Thanks for sharing this information ! 👍👍👍 !

[@MooseOnEarth]

This is not really smart charging, but standard AC charging with simple communication via PWM. Actual smart charging is in ISO 15118, which can also be used over AC. It is a much more sophisticated protocol.

[@Tony770jr]

Nice info, thanks!

[@aor3200]

Good explanation, thank you

[@bryanandrestoalomboquinato1360]

Thanks for the information

[@mukesh4984]

Excellent video

[@paweb.1092]

12:45 How to calculate duty cycle for higher current (etc. 400Amps that are often used in DC chargers)

[@StevenPeeters]

DC charging uses a totally different protocol. PWM duty cycle between 3% and 7% forces PLC communication following ISO15118 or its predecessor DIN70121

[@paweb.1092]

​@@StevenPeetersso they still uses PWM signal but with diffrent formula or how does it work ? 😢

[@StevenPeeters]

@@paweb.1092 no, the PWM is only used to let the car know it needs to use PLC communication instead

[@bhargavkshirsagar8605]

Excellent 👍.

[@anhhoangtuan2286]

thanks for the video.

[@StevenPeeters]

You’re welcome

[@toptenzz8925]

Great explanation hattsoff

[@StevenPeeters]

Thank you for your kind words

[@NG-oo5gn]

Thankyou for sharing

[@CyrusXIII]

thank you!

[@wrightwells]

What about resistance within the plug to determine the maximum amperage of the cable used.

[@M0re85]

First of all. Thanks for the video and the explanation. Very clear! I have a question regarding the duty cycle length. In case of an Wallbox with Overload protection installation, the wallbox power adapts the maximum Amper they can supply in every moment. How this affects to the Control Pilot duty cycle signal? What says the standard? Do the states C & D accept variable duty cycle?

[@StevenPeeters]

Yes, the duty cycle can change during the charging session. That is how you can use solar power only, for example. the car will adapt to the duty cycle to determine how much power it draws

[@ukvette]

Thats a very good explanation on how EV (Tesla) charges. So the CP pin controls when, and how much the Tesla can draw power out of the wall charger. So effectivly, the power company can stop yo charging your EV if they so wish? I guess one should prevent the energy company from getting to your control pin. It might be possible to isolate the control pin, and have an external voltage control to said pin, to bypass the possibility that your energy company shuts down your EV charging.

[@StevenPeeters]

Correct. In Luxemburg ist is mandated by law that the power company can limit your charger to what they call “safe mode”. This is mesnt to alleviate the grid when it is overloaded. Kind of like when in the US the Powerwall can be made to dump power on the grid in certain areas. Just to balance the grid

[@Fraiyia]

Used pulse width modulation in synthesizer music in the 80’s also in electronics class using a 556 timer to control industrial circuits using solid state relays .

[@jeffbosch1697]

You can also use it to make LEDs dimmable.

[@Fraiyia]

@@jeffbosch1697well you can control the duty cycle and make the LEDs more efficient .

[@jeffbosch1697]

@@Fraiyia And the brightness. You can also control the speed of a DC motor with PWM.

[@Fraiyia]

@@jeffbosch1697 I am an electronics engineer . This is my field . However thank you for providing that bit of 2nd quarter electronics and industrial control , perhaps you are more accustomed to girls who studied at beauty schools and did well in home ec yes ?

[@jeffbosch1697]

@@Fraiyia Is the snippiness really necessary?

[@SauravKumar-yn2nv]

Hello Steven, very nice video with elaborate explaination of all state. I have a question though: what do you mean by ventilation required in state C, mostly what does ventilation mean in this context ?? or what is a CP Vent??

[@StevenPeeters]

The Ventilation required state would be for a vehicle with Lead Acid batteries. The charging process of Lead Acid batteries produces hydrogen. When an EV requests ventilation the charging point should either turn on ventilation and allow charging or go into an Error state and deny charging.

[@SauravKumar-yn2nv]

@@StevenPeeters so its actually mean ventilating the hydrogen out ?? So here the ventilation is like a air ventilation. Sorry i got so confused as i thought the term ventilation in electical component may mean drawing less current or some kind of circuit state in low power. As i am a software engineer its hard to understand it practically. Plus in my schematic i saw a circuit that says CP vent, now its hard to guess there is a fan in my ECU that turns on for ventilation, so it must mean something different??

[@StevenPeeters]

@@SauravKumar-yn2nv it is the car saying to the EVSE that the area needs to be ventilated

[@vindis79]

Thanks for the video! How would you measure available energy to set pwm signal on offgrid solar system? I can only think of light sensor and mapping the value from that to estimate what solar system outputs.

[@StevenPeeters]

You just put magnetic measuring clamps or an electronic circuit on your main line and measure positive or negative power consumption and act accordingly

[@vindis79]

@@StevenPeeters Not sure if I follow you. I have no main line. It's an offgid system. I have to create a load in order for the invertor to generate something. I don't know what the load would be. It depends how much solar panels can generate at a given moment. The load could be the solar batteries and if the inverter decides tu pull some current from them than that could be a signal to limit current for the car. Not sure though what charger would have this capacity to adjust charge current based on current flow from the solar batteries. Any ideas? Thanx.

[@StevenPeeters]

@@vindis79 you’d need a charger with an interface. Maybe an OCPP connection. You can use that system to limit the available current. The charger will then take care of the pwm signal. But you’ll have to monitor your capacity remotely though.

[@navjotsingh-bg2co]

Hi Steven.!! Thanks for the explanation it really helps me to understand the concept. However, I have a question about the CP and Earth. I just want to know why we are shorting resistance and diode with earth terminal. It shouldn’t be with Circuit ground?????

[@StevenPeeters]

Thanks for your question. However, I'm not an electronics engineer. I'm sure there is a good reason for it and someone smarter than me can answer that...

[@slavric]

@@StevenPeeters It is shorted thru the diode so the negative side of the waveform stays intact. Proper EVSE must detect that and deny charging if -12V is loaded and drops closer to GND but some don't.

[@ukvette]

​@@slavric thanks ,👍

[@HenryLoenwind]

Earth is circuit ground here for a number of reasons: 1.) J1772 (CCS1) doesn't carry neutral, only L1 and L2. (The pin often is labelled as N, but the intended use also is split-phase 240V US home installations (L1-N-L2).) 2.) Type 2 plugs are also designed for DC, and then the N pin is DC-. 3.) When used for DC as CCS, the N pin is completely missing from the plug. So short of adding a signal ground pin, the earth pin is the only constant one.

[@fotoamgamgfoto3695]

Hi! I have a type 2 one phase L1 to Schukko cable. It does not have any pwm stuff inside. just a directly connected wire instead of button to signal proximitry and a resistor for max 16Amps current setting. I plan to extend it and put 2 more chargesers on one by one on L2-N, L3-N pins. I will wire Schucko plug socket for them. Sono extra electronic and stuff needed? I will have max 16Amps at both phases on 230V AC? so 3 times 16Amp current max? My chargers are L1 1.3kW, L2 2kW, L3 2kW. I have to plug L1 first, that has CAN communication to battery to open relay. I will plug in other 2kW chargers manually to socket on L2 then L3. I think better to use both phases instead of L1-N only to be similar flow on neutral, but some charge stations like in india have one phade Type2 AC only.... I am in EU, Hungary, here 3 phase is the common and if not balanced 3 phase load it reduce max power to 3.6kW.

[@joeabad5908]

Thank you Steven for this detailed explanation. I am converting a mini suzuki pickuo to an EV. I want to access a public charger but I undrrstand it need a specific signal to activate. Can you give advise on how to trigger the public charger to provide 220 supply on the J1772 plug/connector? Godbless your channel😊

[@StevenPeeters]

Thank you for the kind words. And nice little project you hot going there. 👍 Sadly, I have no clue about the J1772 adapter. Also, a public charger will require some authentication with a badge most likely. If that is not what you mean, than please explain the situation in more detail, because then I must misunderstand the question. The BMS should take care of all communication.

[@joeabad5908]

@@StevenPeeters thank you so much for replying. J1772 is a normal plug on public chargers that fits most EV (ie Nissan Leaf) I need to turn on a public charger to charge my battery pack (EVMini Pickup-Future). I understand it needs a signal from the car/battery pack to trigger the charger to switch ON. I am looking for a simpler way to do this without having the modulator circuit in the CP terminal.

[@StevenPeeters]

@@joeabad5908 the CP state is that trigger. You need to go to state C or D for starting the charge

[@FiguresOfAntiquity]

Hey nice video. What I still dont get it what if the following scenario occurs: Charger sais car can load with 32A Car can only load with lower Ampere (lets say 16A) Is the PWM Signal then beeing changed by the car?

[@StevenPeeters]

The charger detects less current is being drawn and then adjusts the PWM to match the car's power request.

[@stefanopellini2464]

This protocol that works with pwm modulation is OCPP protocol or anotherone? Thanks

[@StevenPeeters]

PWM and OCPP are 2 totally different protocols. PWM is between charger and car. OCPP is used for communication between charger and some backend software package.

[@cristiciuc5378]

Just curious: would you consider STATE E as an error state? So , from OCPP(1.6) p.o.v. should this be FAULTED?

[@StevenPeeters]

E is indeed an error. I believe it is a communication diode error, if I remember correctly

[@camilledehaes754]

Thanks for the explanation. Looking into charging and decharging using V2L I do have some questions. As explained CP is used to communicate how much can and may be charged but in the sockets of the loading cable CP is connected to PE and PP is connected to PE via a resistor of which the impedance will show the car and the loading station the cable is 16A or 32A ready but there is no connection between PP of the car and PP of the loading station, the same for CP. Both are connected to PE. Discharging an other resistor is used between PP and PE to let the car now it may allow disharching but during disharging it is a floating system, PE is not connected to ground. I do not understand how PMW communicates with the car as there is no direct connection between CP of charger and CP of the car?

[@StevenPeeters]

V2X is not possible with AC. Onboard chargers are not capable. Needs a DC charging station to work bidirectionally

[@camilledehaes754]

​@@StevenPeeters V2L is AC and easily can be used in combination with an all in one hybrid inverter using the Gen input or with an island inverter using the Gen port or grid input and an ATS. This is not a problem at all. Most hybrid inverters even have a dry contact for making an N-bound if needed.( v2L is a floating system) I am looking into switching between charging and de-charging (V to Load, not vehicle to grid. ) without having to change the type 2 plug. During the day charging using solar pwr, during the night V2l to home. This without a very expensive bidirectional wallbox . In an MG de-charging must be activated in the car which is not usable but a BYD just needs plugging in and provide the correct resistance between PP and PE. We just have to simulate the socket has been removed and switch between different resistance. As far as I know there is no direct connection between CP or PP of the car and CP or PP of the charger.

[@DPTech_workroom]

Hello! I'm planning to assemble a charger for an E-bike battery (LG Chem 63b - 14s3p, 48-58v 180A) with a type 2 connector with 3 phase. How can I make it work correctly? I have 3 pcs. power supply 58.8v 50A (input 220v AC nearly 16A). They will be built in the bike. I'd like to charge it from home at 220v 1 Phase AC, at work using a 3 Phase 380v (it's a 3 times 220v) and using a real charging station. The home and work there is no issues, because it can be connected directly. But how can I charge on a Charging station? Are there topics to figure it out? Or with ready solution?

[@StevenPeeters]

Good luck with your project, but I'm no hardware engineer. There are several norms that charging stations need to follow. Probably something with the communication of the EV state, I would assume. But sorry, can't help you there

[@user-zo4qz8zy7o]

Hello, thank you for this explanation but i have a question. The 12V DC that gets supplied at state A, is that the same current that charges the ev? If the charger is an AC charger shouldn’t the current emitted be alternating and not direct? I don’t quite understand this part and would like an explanation, thank you in advance

[@StevenPeeters]

It is 12V AC as you can see in the graph

[@user-zo4qz8zy7o]

@@StevenPeeters okay i see. Reason why i asked this is because in a published paper they said that the evse supplies 12V of dc to the pilot line and i got confused.

[@tomasbengtsson5157]

@@user-zo4qz8zy7oNo it’s not that power that charges your EV. The EVSE (charge box) supplies only low voltage control signals on the Control Pilot wire. At the start 12V DC is normally supplied on the CP wire in state A. This indicates to the EV (vehicle) that the EVSE is connected. The EV then pulls down the 12V to 9V to request power. The EVSE then switches the DC 12 V to a pulse with modulated AC signal (+-12V) pulled down by the EV to 6V when ready to accept power. The actual power to charge your EV is supplied on the 3-phase pins, normal 400V 3-phase AC from the grid (or 230V 1-phase if you charge from a normal schuko outlet) In state A nothing is supplied on the 3-phase high power pins and no charging occurs at that state.

[@ilkosj]

I just got Ford Transit EV and I would like to install solar modules and 120Vac inverter (because is cheaper than 240Vac inverter) to provide power to the van while I'm driving or parked. What do I need to be aware of, to make this possible? I want to tap to the wires of the plug on the vehicle between the plug and Charger or BMS in the vehicle. The dealer couldn't give me enough info. Please advise.

[@StevenPeeters]

Solar has nothing to do with charging your car at all. You need a smart charger that can take your injection into account. But your solar inverter will give you AC power in your house and the charger puts that into your car

[@JK-tb8ns]

On AC charging does the EVSE comunicate with EV ? what kind of messages does it exchange? Wich protocol do they use ?

[@StevenPeeters]

No vehicle communication. Just the PWM signal

[@JK-tb8ns]

@@StevenPeeters they dont use PLC ?

[@k1zmt]

What about the voltage? Is it 230V or something else? I saw a few different voltages in the standard but I don't understand how does it get determined?

[@StevenPeeters]

One of my first videos explains the different voltages in 3-phase grids. kzbin.info/www/bejne/fojGqa19fdGEes0

[@k1zmt]

@@StevenPeeters thank you! It’s a classic 1-phase / 3-phase system. I understood now. It seems like all the logic is implemented within a car and as long as 1 phase is used there should not be any problems.

[@StevenPeeters]

@@k1zmt It is indeed the onboard charger that determine what it will and will not charge on. The wall charger itself is just a dumb power provider (unless you get a smart charger of course, but that doesn't change the car's behaviour)

[@vahagnmelikyan2906]

Do evs have other charging ports? Like plugin directly from solar?

[@StevenPeeters]

There always needs to be a charging device involved. There are other ports in the US, for example, like the Tesla connector or CCS1 for DC charging. But for Europe, type 2 is the standard for AC and CCS2 for DC, with a few cars still on CHAdeMO for DC

[@vahagnmelikyan2906]

@StevenPeeters so if I cut the wire from CP sensor and attach it to 6v+ (something like that) pwm at 10% duty cycle I'll cause the car to pull minimal amount of current? Can I just get a 200w solar panel connect it to inverter 120vAC and get one of the home ev chargers. Would the charger reduce the duty cycle when it senses the voltage dropping and send a signal to car to reduce current usage?

[@StevenPeeters]

@@vahagnmelikyan2906 no idea, but don’t do that. You’ll void the car’s warranty for everything electric (so everything basically)

[@cees1910]

Hi If i have a convert cable from type 2 to shuko how can it detect there is a car? Since i did a test with this cable and attached a grinding machine on it ,and it runs so no checking is done with the car or charger ,how is that possible cannot be save that you can do that . It was on 11 kw charger

[@StevenPeeters]

Schuko can’t detect anything. It doesn’t have the CP cable.

[@cees1910]

I know is this not dangerous, should they not take action to this at public charger stations

[@jagarcogheart]

So can a 3 phase charge point not tell a vehicle how much it is allowed to draw from each phase but only all three at once?

[@StevenPeeters]

Correct. The load should always be spread over all phases for a balanced neuter

[@Tony770jr]

Does the fast DC charging system use the same PWM?

[@StevenPeeters]

Yes and no. When DC charging, the voltage levels on the CP are still used to communicate the state of the vehicle (A/B/C/D/E/F), but the PWM will be at 5% to indicate that a different high frequency communication will be used for the charging. This way, the CCS protocol allows for much more information to be communicated, such as the state of charge, for example, which cannot be communicated with simple AC charging. When DC charging, the onboard charger is kind of bypassed as the inverter doesn't have to do any work converting AC to DC. It's a bit simplified, but the while charging procedure is different with DC.

[@Tony770jr]

@@StevenPeeters How does the communication work on these DC chargers, do you have an example?

[@StevenPeeters]

@@Tony770jr it is using digital communication like LAN communication, with packages and headers. It is quite complicated. Here is a good document if you have trouble sleeping 😉 tesla.o.auroraobjects.eu/Design_Guide_Combined_Charging_System_V3_1_1.pdf

[@kjchetan6770]

@@Tony770jr Communication in Dc charging happens via Control pilot low level communication (PWM) and high level communication (PLC powerline communication) . In case of CHademo and GBT standards communication happenes via CAN

[@gohkairen2980]

is there a way for us to create a device that allow us to send a signal via CP and control its battery management system(bms)? Currently working on a project to create a device that can allow us to cut of all power supply from the battery in order for firefighters to carry out safe operations on the EV.

[@StevenPeeters]

I think you’d need a physical connection to do that. And the situation you describe is exactly why there are cutting points indicated to cut through the high voltage wires. That is already on the cars.

[@gohkairen2980]

@@StevenPeeters cutting point varies in different ev/hybrid and that's why we wanna come out with something more universal or something that car manufacturers can implement with software updates. Hence the idea of designing some sort of plug that sends signal to cut the power electronically instead of physically. Do let me know if you think if it's feasible by sending signals from CP to either BMS or the motherboard

[@StevenPeeters]

@@gohkairen2980 in the US you now havecsome kinfmd of breakaway adapter for Tesla, marketed gor when you are being robbed. But it needs to send a stop charging manually from the screen, but then does allow to go to state A while still plugged in. But it is an additional plug you’d have to use

[@gohkairen2980]

@@StevenPeeters noted will develop a plug and see if car manufacturers are willing to program a signal that allows BMS to disconnect 12v battery

[@baronnolo7467]

Why you do any video when you are still on the screen. Can you explain it visual like drawing on paper. For this you can make a podcast.

[@StevenPeeters]

It is explained with a several drawings. Have you watched the entire video?