3 ms·
Semiconductors are stackable to get higher voltage. They're parallelizable for more current. Cost scales linearly with voltage and current, and is therefore
by londons_explore 2y ago
Semiconductors are stackable to get higher voltage. They're parallelizable for more current.
Cost scales linearly with voltage and current, and is therefore constant WRT to system power.
- tim333 2y agoApparently they use thyristors https://en.wikipedia.org/wiki/Thyristor#HVDC_electricity_transmission https://en.wikipedia.org/wiki/Thyristor#HVDC_electricity_tra... https://en.wikipedia.org/wiki/HVDC_converter#Thyristor_valves https://en.wikipedia.org/wiki/HVDC_converter#Thyristor_valve...
- londons_explore 2y agoThyristors require you have at least one transformer operate at AC line frequency (50/60Hz). That costs a lot, since you need enough steel to store 20 milliseconds of your total power as a magnetic field. Thyristors are on-off devices (like most semiconductors when used for power conversion), but cannot turn off without zero current, which precludes a bunch of high frequency designs which are better for harmonics and weight-of-steel. Overall, they were a popular choice in the 90's and 2010's, but I don't think we'll see any new designs installed with them.
- tim333 2y agoAh - right you are. Seems IGBTs are the thing now.
- coryrc 2y agoI've never heard of MOSFETs being used in extra-high voltage systems, but I have not been following the industry for a while. Do you have any links? I've only seen IGBTs or older technology used.