Re:Tesla adds bidirectional charging capability
by londons_explore on Thursday May 21, 2020 @03:46AM
(#23255829)
> The inverters are designed for power and cost efficiency, so I'd say it is unlikely that are capable at outputting anything other than the high-voltage, high-frequency power intended for the electric motor.
You could use the motor inverters for this, if only they weren't already connected to the motors. You can't have your wheels spinning just because you want to hook up an AC device.
Instead you'd use the charging inverter. Large modern chargers are combinations of MOSFETs, capacitors, and inductors, which are all components where the power flow is reversible. There is also an isolation transformer which the motor drive inverters don't have, and is important for detecting potentially dangerous faults.
This isn't true with say your laptop charger, since it's input stage typically uses diodes rather than MOSFETs for the initial rectification, which means you couldn't run the whole thing in reverse to make AC off your laptop battery, even with new firmware.
You could use the motor inverters for this, if only they weren't already connected to the motors. You can't have your wheels spinning just because you want to hook up an AC device.
Instead you'd use the charging inverter. Large modern chargers are combinations of MOSFETs, capacitors, and inductors, which are all components where the power flow is reversible. There is also an isolation transformer which the motor drive inverters don't have, and is important for detecting potentially dangerous faults.
This isn't true with say your laptop charger, since it's input stage typically uses diodes rather than MOSFETs for the initial rectification, which means you couldn't run the whole thing in reverse to make AC off your laptop battery, even with new firmware.