[Frigzy]

Inverter and charger are two drastically different devices. An inverter doesn't do any voltage conversion, it's just PWM-ing the input voltage. A charger is a full-blown step-up/step-down converter with a dedicated transformer. I can imagine, that an inverter can be used as a charger in some limited cases, but its input/output voltage range is going to be very restricted and efficiency is going to be poor.

 

[Frigzy]

what Frigzy said about "simple PWM" doesn't apply to AC/BLDC controllers(inverters).

Sorry, but what is the principal difference (electrically-wise) between brushed and brushless inverter except for the 3-rd half bridge?
As it gets to the charging, there are 2 main problems:
1) You get 240V in the outlet (345V DC). How on Earth are you going to step up that voltage to 420V in order to charge a 400V battery pack using, basically, 3 half-bridges? What to do with 120V (level 1) charging?
2) Since you cannot really regulate the voltage, only the duty cycle of the PWM. You have to skip a part of a sine wave in order to bring voltage down, just like a dimmer switch. The power factor of such system is going to be a disaster, no regulation authority ever would approve that for customer use. There is a reason why there is a switching transformer inside your phone charger and not just a PWM-ing transistor bridge.

 

[Frigzy]

I agree with you that stepping up voltage is probably one of the main issues here, when the charging AC input is significantly lower than what the battery pack requires. At the same time, here is what a trivial boost converter looks like :

https://tinyurl.com/ydo6e8kt

and the inverter already has the MOSFETs or IGBTs for controlling the phases and current.

Thank you for the boost converter animation - that's a good one. The inverter is still missing the main component - an inductor or a transformer. If we somehow add an inductor to the inverter, then yes - maybe it can work as a poor-man charger. Modern chargers are based on resonant topologies. It would take a quite severe modification to the inverter to enable such topology. A proper charger would have a PFC/boost stage. That can be made out of another inverter. I'm not sure if the result can still be called an inverter.
Again, I'm not saying, that it cannot be done - it totally can. But the result is going to be much inferior to a proper charger. Also, I don't know anything about the Prius inverter/converter module. However, I have a decent knowledge of Tesla components.

 

[Frigzy]

so here is an ignorant question, explain to me how the Prius Inverter/Converter is working then in the video above?

My understanding of it is: when the voltage is too high, it's skipping part of the sine wave that's coming from the motor to keep the voltage low. When the voltage is too low, it's boosting the voltage using motor windings as inductors. The efficiency of that process is poor (60-70%) and the power factor is garbage, but no one cares about the power factor within the powertrain. I'm not an expert on Prius though, maybe they put some marvel of electrical engineering in there, who knows.