5 ms·

Inverters with constant full load capability for electric drives

74 points by cl3misch 3y ago

_Microft 3y ago
If you are wondering about the project name "Dauerpower": "Dauer-"/"andauernd" means permanent/permanently/continous and and - equally important - it rhymes with power ("d-ower"). Here [0] is a longer article by Fraunhofer on silicon carbide power electronics. Depending on how much you want to know, there are Wikipedia articles on a number of terms used in it (SiC, MOSFET, wire-bonding, micro-via, parasitic inductance, IGBT, ...; there is also an explanation of "PCB embedding" on the Fraunhofer website [1]). [0] https://blog.izm.fraunhofer.de/silicon-carbide-for-power-electronics/ https://blog.izm.fraunhofer.de/silicon-carbide-for-power-ele... [1] https://www.izm.fraunhofer.de/en/abteilungen/system_integrationinterconnectiontechnologies/arbeitsgebiete/pcb-embedding.html https://www.izm.fraunhofer.de/en/abteilungen/system_integrat...
- algo_trader 3y ago
  What is the cheapest/simplest configuration for an agricultural PV-to-always-on-e-motor (1MW)? We can serialize the PVs to get 1000v? And then feed that directly to a (suitable) drive without an inverter? Possibly even a DC motor? This cuts out half the components compared to an EV drive train, since we have much simpler cooling/packaging/response demand?
  - WJW 3y ago
    What is even the the point of that? An always-on (presumably only on during daytime?) 1 MW motor with enough solar panels to power them and something that actually requires a full megawatt would be pricy enough that the cost of an inverter would not be all that large percentage wise. Especially since you almost certainly would want to have some sort of controller for the motor anyway, which would need the same type of electronics as an inverter would need.
    - rdl 3y ago
      I would assume a huge pump of some kind.
    - jandrese 3y ago
      Probably an irrigation pump that needs to move water uphill. Water is heavy.
  - deleted 3y ago
    [deleted]
  - AYBABTME 3y ago
    What sort of agricultural PV-to-always-on-e-motor object would require 1MW continuously? That's a lot of power for agriculture purposes.
  - namibj 3y ago
    Most modern panels seem to be rated for a system voltage of up to 1500V; i.e., you're allows to connect enough in series to get up to but not beyond, as long as your MPPT can cope. And yeah, 1kV target is practical, you could run a triple half bridge inverter from that into a motor with enough stray inductance to smooth the PWM into pure sine, yeah. It can do the MPPT task at the same time, btw.
    - lazide 3y ago
      The issue is available power is almost never going to be constant enough to directly couple to a load - a cloud passes by and your motor will stall. 1PM on a sunny day, and you’ll be using 1/3 of your power, etc.
  - shkkmo 3y ago
    If your feeding DC from PV to a motor without an inverter, it will be a DC. If you hook a brushless motor straight to PV panels, the speed the motor runs at vary throughout the day as the volatage output of the panels waxes and wanes. You'll need to make sure that it the motor has sufficient cooling to not damage itself when running at full power on the hottest sunniest day. Generally, almost every type of PV or DC electric motor setup has a one or more systems that manage volatage, either in the form of a charge controller the outputs a constant(ish) voltage given the varying input voltages provided by the PV, or an ESC that outputs varying voltages to the motor to change it's rate of speed.
  - quailfarmer 3y ago
    To get good efficiency from a solar panel you must continuously track the “Maximum power point” (MPPT). You would never want to run a motor directly off the solar, you want a power converter to maximize efficiency.
- yobbo 3y ago
  Closest English cognate is probably "enduring".
  - jjtheblunt 3y ago
    in both cases, German and English, through Latin borrowing https://en.wiktionary.org/wiki/dauern https://en.wiktionary.org/wiki/dauern
tgtweak 3y ago
Cool project, I like the incorporation of 3d-printed copper heat syncs with integrated coopant channels to the specific components so that they can control coolant distribution more accurately. That has applicability in many other areas. As battery tech gets better and energy densities increase, these improvements in inverter tech are critical to keep up. This could also mean improved AC output in battery energy storage systems as wel.
pfdietz 3y ago
Inverters are becoming a larger fraction of the cost of PV systems, so improvements in the technology are welcome there as well.
CoastalCoder 3y ago
Which components in a modern house could run as, or more, efficiently if fed DC power? I'm guessing this includes: - Most electronic devices that require AC->DC power adapters. Including CPUs, GPUs, and everything powered by USB. - Electric stoves, ovens, and other simple electric heaters.
- realreality 3y ago
  > Electric stoves, ovens, and other simple electric heaters. Not really. The current would be too high on low voltage DC. And high voltage DC is dangerous.
  - user_7832 3y ago
    > And high voltage DC is dangerous. Is this also at 120V or 220V DC? Is it due to how the alternating current allows muscles to release? (Or was that just a myth?)
    - wcunning 3y ago
      It matters for switches and things releasing in a physical sense, so muscles may not come into it. Also, there are issues with high voltage DC contactors welding themselves closed in high demand EV situations because they were sized incorrectly or had poor control.
      - user_7832 3y ago
        Thanks, dangerous in the sense of damaging equipment/starting a fire? (As opposed to say shocking someone) > Also, there are issues with high voltage DC contactors welding themselves closed in high demand EV situations because they were sized incorrectly or had poor control. Would this have have made a difference if it were AC? I think AC welding is also a thing.
        wcunning 3y ago
        AC definitionally has zero voltage 60 times a second, so when you try to "disconnect" by breaking the switch, the flowing electricity doesn't hold the switch closed. It's why when you look at relays they're rated for 12VDC or 120VAC (that and the commonality of house voltage and automotive voltage). I think the true values are probably a little higher in each, but you'd find that relays cannot break contact at 120VDC where they can at 120VAC.
crmd 3y ago
> Following a simulation phase, the prototype is currently under construction and will ultimately undergo an extensive testing process at Porsche AG
kwhitefoot 3y ago
What's the real application here? It surely can't be automotive, the amount of time spent at full load is minuscule at least in cars. My old Model S has a full load output of 250 kW but the typical load is less than 30 kW. Lower power cars spend a bit more time at a higher fraction of full load but still typically far less than 50%. Of course efficiency and cooling are important but EV drives are already quite efficient and rarely operate at full load so the improvement in practice will be small. Or is the mention of automotive use relevant only because Porsche is involved in testing?
- lazide 3y ago
  100% duty cycle capable means more durable and capable of industrial use, racing, aerospace, military. Think mining haul trucks, industrial process control, towing, semi trucks, race cars, electric helicopters, water pumps, etc. also, likely capable of 150% for short bursts (military power)
  - p1mrx 3y ago
    > also, likely capable of 150% for short bursts Existing inverters are already capable of 150% for short bursts, if you define 100% to be the constant full load capacity.
    - lazide 3y ago
      At 1MW?
      - kwhitefoot 2y ago
        Why not. 1.5 MW is only six times the maximum power of my ancient 2015 Model S 70D. The inverters are tiny.
        lazide 2y ago
        ‘Only’ And not rated at 100% duty cycle probably?
1letterunixname 2y ago
Related: An article comparing Si IGBTs and SiC MOSFETs. https://www.arrow.com/en/research-and-events/articles/advantages-of-sic-mosfet-vs-si-igbt https://www.arrow.com/en/research-and-events/articles/advant...

74 points by cl3misch 3y ago

If you are wondering about the project name "Dauerpower": "Dauer-"/"andauernd" means permanent/permanently/continous and and - equally important - it rhymes with power ("d-ower"). Here [0] is a longer article by Fraunhofer on silicon carbide power electronics. Depending on how much you want to know, there are Wikipedia articles on a number of terms used in it (SiC, MOSFET, wire-bonding, micro-via, parasitic inductance, IGBT, ...; there is also an explanation of "PCB embedding" on the Fraunhofer website [1]). [0] https://blog.izm.fraunhofer.de/silicon-carbide-for-power-electronics/ https://blog.izm.fraunhofer.de/silicon-carbide-for-power-ele... [1] https://www.izm.fraunhofer.de/en/abteilungen/system_integrationinterconnectiontechnologies/arbeitsgebiete/pcb-embedding.html https://www.izm.fraunhofer.de/en/abteilungen/system_integrat...

algo_trader 3y ago
What is the cheapest/simplest configuration for an agricultural PV-to-always-on-e-motor (1MW)? We can serialize the PVs to get 1000v? And then feed that directly to a (suitable) drive without an inverter? Possibly even a DC motor? This cuts out half the components compared to an EV drive train, since we have much simpler cooling/packaging/response demand?
- WJW 3y ago
  What is even the the point of that? An always-on (presumably only on during daytime?) 1 MW motor with enough solar panels to power them and something that actually requires a full megawatt would be pricy enough that the cost of an inverter would not be all that large percentage wise. Especially since you almost certainly would want to have some sort of controller for the motor anyway, which would need the same type of electronics as an inverter would need.
  - rdl 3y ago
    I would assume a huge pump of some kind.
  - jandrese 3y ago
    Probably an irrigation pump that needs to move water uphill. Water is heavy.
- deleted 3y ago
  [deleted]
- AYBABTME 3y ago
  What sort of agricultural PV-to-always-on-e-motor object would require 1MW continuously? That's a lot of power for agriculture purposes.
- namibj 3y ago
  Most modern panels seem to be rated for a system voltage of up to 1500V; i.e., you're allows to connect enough in series to get up to but not beyond, as long as your MPPT can cope. And yeah, 1kV target is practical, you could run a triple half bridge inverter from that into a motor with enough stray inductance to smooth the PWM into pure sine, yeah. It can do the MPPT task at the same time, btw.
  - lazide 3y ago
    The issue is available power is almost never going to be constant enough to directly couple to a load - a cloud passes by and your motor will stall. 1PM on a sunny day, and you’ll be using 1/3 of your power, etc.
- shkkmo 3y ago
  If your feeding DC from PV to a motor without an inverter, it will be a DC. If you hook a brushless motor straight to PV panels, the speed the motor runs at vary throughout the day as the volatage output of the panels waxes and wanes. You'll need to make sure that it the motor has sufficient cooling to not damage itself when running at full power on the hottest sunniest day. Generally, almost every type of PV or DC electric motor setup has a one or more systems that manage volatage, either in the form of a charge controller the outputs a constant(ish) voltage given the varying input voltages provided by the PV, or an ESC that outputs varying voltages to the motor to change it's rate of speed.
- quailfarmer 3y ago
  To get good efficiency from a solar panel you must continuously track the “Maximum power point” (MPPT). You would never want to run a motor directly off the solar, you want a power converter to maximize efficiency.
yobbo 3y ago
Closest English cognate is probably "enduring".
- jjtheblunt 3y ago
  in both cases, German and English, through Latin borrowing https://en.wiktionary.org/wiki/dauern https://en.wiktionary.org/wiki/dauern

tgtweak 3y ago

Cool project, I like the incorporation of 3d-printed copper heat syncs with integrated coopant channels to the specific components so that they can control coolant distribution more accurately. That has applicability in many other areas. As battery tech gets better and energy densities increase, these improvements in inverter tech are critical to keep up. This could also mean improved AC output in battery energy storage systems as wel.

pfdietz 3y ago

Inverters are becoming a larger fraction of the cost of PV systems, so improvements in the technology are welcome there as well.

CoastalCoder 3y ago

Which components in a modern house could run as, or more, efficiently if fed DC power? I'm guessing this includes: - Most electronic devices that require AC->DC power adapters. Including CPUs, GPUs, and everything powered by USB. - Electric stoves, ovens, and other simple electric heaters.

realreality 3y ago
> Electric stoves, ovens, and other simple electric heaters. Not really. The current would be too high on low voltage DC. And high voltage DC is dangerous.
- user_7832 3y ago
  > And high voltage DC is dangerous. Is this also at 120V or 220V DC? Is it due to how the alternating current allows muscles to release? (Or was that just a myth?)
  - wcunning 3y ago
    It matters for switches and things releasing in a physical sense, so muscles may not come into it. Also, there are issues with high voltage DC contactors welding themselves closed in high demand EV situations because they were sized incorrectly or had poor control.
    - user_7832 3y ago
      Thanks, dangerous in the sense of damaging equipment/starting a fire? (As opposed to say shocking someone) > Also, there are issues with high voltage DC contactors welding themselves closed in high demand EV situations because they were sized incorrectly or had poor control. Would this have have made a difference if it were AC? I think AC welding is also a thing.
      - wcunning 3y ago
        AC definitionally has zero voltage 60 times a second, so when you try to "disconnect" by breaking the switch, the flowing electricity doesn't hold the switch closed. It's why when you look at relays they're rated for 12VDC or 120VAC (that and the commonality of house voltage and automotive voltage). I think the true values are probably a little higher in each, but you'd find that relays cannot break contact at 120VDC where they can at 120VAC.

crmd 3y ago

> Following a simulation phase, the prototype is currently under construction and will ultimately undergo an extensive testing process at Porsche AG

kwhitefoot 3y ago

What's the real application here? It surely can't be automotive, the amount of time spent at full load is minuscule at least in cars. My old Model S has a full load output of 250 kW but the typical load is less than 30 kW. Lower power cars spend a bit more time at a higher fraction of full load but still typically far less than 50%. Of course efficiency and cooling are important but EV drives are already quite efficient and rarely operate at full load so the improvement in practice will be small. Or is the mention of automotive use relevant only because Porsche is involved in testing?

lazide 3y ago
100% duty cycle capable means more durable and capable of industrial use, racing, aerospace, military. Think mining haul trucks, industrial process control, towing, semi trucks, race cars, electric helicopters, water pumps, etc. also, likely capable of 150% for short bursts (military power)
- p1mrx 3y ago
  > also, likely capable of 150% for short bursts Existing inverters are already capable of 150% for short bursts, if you define 100% to be the constant full load capacity.
  - lazide 3y ago
    At 1MW?
    - kwhitefoot 2y ago
      Why not. 1.5 MW is only six times the maximum power of my ancient 2015 Model S 70D. The inverters are tiny.
      - lazide 2y ago
        ‘Only’ And not rated at 100% duty cycle probably?

1letterunixname 2y ago

Related: An article comparing Si IGBTs and SiC MOSFETs. https://www.arrow.com/en/research-and-events/articles/advantages-of-sic-mosfet-vs-si-igbt https://www.arrow.com/en/research-and-events/articles/advant...