Never stop making videos i study automotive engineering at a polytechnic in Finland with a huge interest in electrical engineering. Matter of fact i'm planning on getting a master of science degree in electrical engineering in university at some point. Your content is literally the best and many of your subjects refer directly to the automotive industry so i thank you for that.

The heat pump is beyond competition

Having driven EVs for about 10 years in a place that has cold winters (New England) - by far the most efficient way to warm the occupants - is to heat the seats, and the steering wheel. And by FAR the most efficient way to defrost the windshield and mirrors etc - is to directly heat them. The windshield can have a very thin (like a few molecules) layer of silver in the glass, and you can very quickly defrost the whole windshield for a few hundred watts. A heat pump is the most efficient way to warm the air in the vehicle - and when you have good seat heaters and a direct heating windshield - then it is actually quite rare to also need to heat the air. The engineering mindset for ICE vehicles is wrongheaded for designing EVs. In ICE vehicles which waste 70-75% of the energy in the gasoline - you have tons of "free" heat, so heating the air to then heat the people or the windows - doesn't matter. But, by heating the things that need it directly (avoiding the lag time and inefficiency of transferring the heat to the air - you are most likely far better off than trying to come up with ways of wasting energy to make heat to then gather it up and then distribute it.

That sounds more like they are trying to reduce the number of easy repairs and increase the reliance on "certified" shops.

Heat the seats steering wheel and windshield directly, heating the air is a luxury.

Its trivial to dissipate heat in the stator of a induction or bldc motor without generating torque... thats a much better route. Since approx 2021 teslas can waste heat in their motor/inverter and pipe the coolant through the heat pumps cold side. This is done when the outdoor temp is too cold for the heat pump

I skipped the intro.. was confused the whole time because you kept saying that you wanted more loss and less efficiency.. I was like "am i stupid or this video makes no f*ing sense ??".. came back to the intro and now it make so much more sense XD

I realize the goal is to reduce total component count but im wondering if its worth it to run the inverters like this. I know its not sexy but just reversing the flow of the already supplied AC cooling system provides a fully functional heat pump heating system too. The bonus is that since most automotive HVAC systems are just pre designed products from third party manufacturers, they achieve economies of scale cost savings. Im stuck on efficiency benefits. Using the inverters is akin to using a resistance heater, just in a different form. Heat pumps are a more efficient method of moving energy from one place to another. When range and battery efficiency are important considerations, does it make sense to do this? Are they just trading one problem for another?

This explains why the drive inverters in my Tesla make a high pitched sound when the car is using them to heat the battery.

Nice way to add the subscribe pitch 👌👌😂

Very interesting video! I never really considered any of this as you've proven once again that my knowledge of FETs is quite lacking.

Heat Pumps underrated. Don't even think about peliter modules.

Wouldn't that be the same amount of power just with additional wear on the inverter vs the heating element

Thanks for your videos. I have often wandered exactly what causes/creates the noise/scream from the inverters of the Siemens Eurostar E320 (train).

plain resistive wire: am i a joke to you? reversible heat pump: hold my beer

You simply adapt the circuit that drives the MOSFET. You drive them from a buss with multiple voltage settings.

It sounds to me that making an inverter deliberately less efficient is another over-complication that is likely to cause more unreliability, by all means harvest the heat from the battery, inverter and motor but keep the resistive heater it's simple and works. The problem of integrating everything is that when one part breaks the whole lot is compromised. The best way to heat a cabin is to harvest the hot air emitted from politicians

Switching time, switching time, switching time, MosFet RdsON, synchronous rectifier, LowΩ inductor, LowESR capacitor, thick PCB tracks, Silver solder...

They would have to waste the same energy in the power devices that would be otherwise invested in resistive elements for heating. So what's the point? Waste energy to get rid of the resistive elements? And don't get me started on the reliability issue, which would be severely compromised, for many reasons... PS: What would make more sense would be to keep going after the highest efficiency possible, but what ever power does get wasted in heatsinks, use it, harness that heat, channel all of it inside the heating matrix, combine it with the usual resistive heating elements, but invest less power on them, just because you use the heat already generated on the power devices. This, to me at least, would make much more sense, using what you already have, and still increasing overall efficiency.

I personally like the method of increasing the f_sw the most, and i feel like you could enhance the loss slightly by using a core material that has more losses at higher frequencies, or use DC current bias and drive the inductors slightly into saturation.