The Most Important Circuit for our Electrical Future! (PFC) EB#55
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Date: 2023-04-02
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Comments and reviews: 15
RedHotFiat
I used to work at a very large manufacturing facility that was built in the late 1960s. This place was so big it had it's own power substation. They had incredible milling machines to create large parts for aircraft. At some point they were experiencing a large lagging power factor issue and the utility was going to require them to pay for a major upgrade to the power lines to the facility. One of their electrical engineers said hold on. He designed a system to use synchronous motors to create a leading power factor to correct the problem. He used these motors to power air compressors for the facility since they used a lot of compressed air. In 1980 we installed a 5000v 500 horsepower synchronous motor. It was the 3rd compressor in that building. Since that time a lot of the electrical loads have been changing. The lighting all changed from fluorescent to high pressure sodium in 1982. By 1990 we were replacing those with metal halide. Now those have been replaced with LEDs. The milling machines are all going to variable frequency drives. I retired in 2012 so I don't see what's going on there anymore.
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I used to work at a very large manufacturing facility that was built in the late 1960s. This place was so big it had it's own power substation. They had incredible milling machines to create large parts for aircraft. At some point they were experiencing a large lagging power factor issue and the utility was going to require them to pay for a major upgrade to the power lines to the facility. One of their electrical engineers said hold on. He designed a system to use synchronous motors to create a leading power factor to correct the problem. He used these motors to power air compressors for the facility since they used a lot of compressed air. In 1980 we installed a 5000v 500 horsepower synchronous motor. It was the 3rd compressor in that building. Since that time a lot of the electrical loads have been changing. The lighting all changed from fluorescent to high pressure sodium in 1982. By 1990 we were replacing those with metal halide. Now those have been replaced with LEDs. The milling machines are all going to variable frequency drives. I retired in 2012 so I don't see what's going on there anymore.
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Cameron
I just want to clarify for at least US viewers that most residential consumers do not pay for their apparent power consumption, only active power (kWh and demand charge in kW) consumption. Industrial consumers have different tiered electricity costs (depending if they are a medium or large power consumer) in which they are either charged with their active or apparent power depending on their power factor (for example, if they have a power factor of less than 0. 9, then the utility would use their apparent power consumption to calculate their billing demand and/or total power consumption. Now if there is going to be stricter regulation on poor power factor (like limit on current harmonics in the video) for consumer products, that's on the manufacturers to ensure there is some sort of power factor correction on either the device or power supplies, not so much on the residential consumer to need to actively seek out power factor correction circuits.
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I just want to clarify for at least US viewers that most residential consumers do not pay for their apparent power consumption, only active power (kWh and demand charge in kW) consumption. Industrial consumers have different tiered electricity costs (depending if they are a medium or large power consumer) in which they are either charged with their active or apparent power depending on their power factor (for example, if they have a power factor of less than 0. 9, then the utility would use their apparent power consumption to calculate their billing demand and/or total power consumption. Now if there is going to be stricter regulation on poor power factor (like limit on current harmonics in the video) for consumer products, that's on the manufacturers to ensure there is some sort of power factor correction on either the device or power supplies, not so much on the residential consumer to need to actively seek out power factor correction circuits.
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23lkjdfjsdlfj
At one time you could make good money solving a similar problem. Maybe you still can? About 30 years ago industrial companies that had unbalanced inductive loads (3-phase) would pay me to balance their capacitive/inductive load. This was important because there was no way to separate inductive power delivery vs capacitive delivery. Iow, when you were using 10 kW of inductive power, the power company would also deliver 10 kW of capacitive power - even if you only needed 1 kW of capacitive power.
I wrote all of the software to solve this problem and all of the inputs I needed were provided on their power bill. Does grid tied equipment take care of this nowadays?
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At one time you could make good money solving a similar problem. Maybe you still can? About 30 years ago industrial companies that had unbalanced inductive loads (3-phase) would pay me to balance their capacitive/inductive load. This was important because there was no way to separate inductive power delivery vs capacitive delivery. Iow, when you were using 10 kW of inductive power, the power company would also deliver 10 kW of capacitive power - even if you only needed 1 kW of capacitive power.
I wrote all of the software to solve this problem and all of the inputs I needed were provided on their power bill. Does grid tied equipment take care of this nowadays?
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education
Memory aid from the old days: ELI the ICE man. (An 'ice man' is someone that delivers blocks of ice back in the pre-refrigeration days, not intended to be a prehistoric human)
ELI means Voltage (E) on an Inductor (L) comes before the Current (I) which builds up more slowly.
ICE means Current (I) through a Capacitor (C) comes before the Voltage (E) which builds up more slowly.
These are not really needed if you know how these components work, but it can help bridge the gap until trained-instinct takes over.
It's a tiny bit interesting (very tiny) that only one symbol/letter out of four ('C') matches its word's first letter ('Capacitor'.
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Memory aid from the old days: ELI the ICE man. (An 'ice man' is someone that delivers blocks of ice back in the pre-refrigeration days, not intended to be a prehistoric human)
ELI means Voltage (E) on an Inductor (L) comes before the Current (I) which builds up more slowly.
ICE means Current (I) through a Capacitor (C) comes before the Voltage (E) which builds up more slowly.
These are not really needed if you know how these components work, but it can help bridge the gap until trained-instinct takes over.
It's a tiny bit interesting (very tiny) that only one symbol/letter out of four ('C') matches its word's first letter ('Capacitor'.
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Jared
The glass analogy never works for me w. r. t. Power Factor. It explains a physical analog of real, apparent, and reactive power, how only real power is useful like the non-foamy part of the drink, but the existence of foam has no relevance to the existence of reactive power.
If we could eliminate foaming from carbonated beverages without affecting their carbonation, we would. But the same isn't true for reactive power, which is absolutely necessary for induction to take place. Similarly, a correction to power factor does not eliminate reactive power, it just offsets for it with added capacitance.
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The glass analogy never works for me w. r. t. Power Factor. It explains a physical analog of real, apparent, and reactive power, how only real power is useful like the non-foamy part of the drink, but the existence of foam has no relevance to the existence of reactive power.
If we could eliminate foaming from carbonated beverages without affecting their carbonation, we would. But the same isn't true for reactive power, which is absolutely necessary for induction to take place. Similarly, a correction to power factor does not eliminate reactive power, it just offsets for it with added capacitance.
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hieyeque1
As a future project, could you make an inverter that corrects square sine wave power produced by a standard gas generator and creates pure sine wave? I'm thinking of something you could plug in to your wall on a specific circuit that creates clean power on that circuit for sensitive electronics for a load of up to 2000 watts. Seems to me silly to have to buy a pure sine wave generator when sometimes all you need to do is clean up the power for a single circuit. This would allow the purchase of a cheap generator, but still get clean power where you need it.
Thanks
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As a future project, could you make an inverter that corrects square sine wave power produced by a standard gas generator and creates pure sine wave? I'm thinking of something you could plug in to your wall on a specific circuit that creates clean power on that circuit for sensitive electronics for a load of up to 2000 watts. Seems to me silly to have to buy a pure sine wave generator when sometimes all you need to do is clean up the power for a single circuit. This would allow the purchase of a cheap generator, but still get clean power where you need it.
Thanks
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Pentium100MHz
Active PFC, such as used in computer power supplies also tends to short and explode when the big high voltage capacitor fails. I ave seen a few of such failed power supplies and managed to repair them. Still, when it fails, it not only turns off the load, but also trips the breaker, which means other stuff turns off as well.
I can just use a bigger cable and avoid this problem. Even if it is not frequent, it is very annoying when it happens.
The power grid sees constant 0. 8 power factor from me though, because that's how the input for my big UPS works.
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Active PFC, such as used in computer power supplies also tends to short and explode when the big high voltage capacitor fails. I ave seen a few of such failed power supplies and managed to repair them. Still, when it fails, it not only turns off the load, but also trips the breaker, which means other stuff turns off as well.
I can just use a bigger cable and avoid this problem. Even if it is not frequent, it is very annoying when it happens.
The power grid sees constant 0. 8 power factor from me though, because that's how the input for my big UPS works.
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purreness
The example with burning wires is inaccurate - no matter how bad the power factor of the power supply is, the temperature of the wire connected to the power grid will only slightly differ from the power supply with a power factor of 1. This is because the heating of the wire does not occur instantly with increasing current, and poor power factor is smoothed out by thermal inertia. On the other hand, large power supplies without power factor correction can affect other power consumers in the circuit and increase the power requirements of transformers in substations.
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The example with burning wires is inaccurate - no matter how bad the power factor of the power supply is, the temperature of the wire connected to the power grid will only slightly differ from the power supply with a power factor of 1. This is because the heating of the wire does not occur instantly with increasing current, and poor power factor is smoothed out by thermal inertia. On the other hand, large power supplies without power factor correction can affect other power consumers in the circuit and increase the power requirements of transformers in substations.
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Wiz
The best approach would be to design the LED driver SMPS circuit with NO 400v capacitor, instead just modulate its PWM to match the full wave rectified 100Hz mains supply, so the current it draws from the mains mimics a resistor (PF = 1.
This will of course echo some 100Hz current ripple to the output (to the LEDs) but that doesnt really matter because humans cant see 100Hz and the output capacitor will reduce that ripple anyway.
You should try building one, it is similar amount of work to the PFC you made here.
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The best approach would be to design the LED driver SMPS circuit with NO 400v capacitor, instead just modulate its PWM to match the full wave rectified 100Hz mains supply, so the current it draws from the mains mimics a resistor (PF = 1.
This will of course echo some 100Hz current ripple to the output (to the LEDs) but that doesnt really matter because humans cant see 100Hz and the output capacitor will reduce that ripple anyway.
You should try building one, it is similar amount of work to the PFC you made here.
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Michael
I would suggest that the title of this video is very misleading. The IEC61000 EMC legislative framework has been in place since the 20th century. The mains harmonic requirements have been revised to make the standard tougher- I think that the latest standards version is something like the 4th revision.
The title of this video suggests that this is a technology that is going to be adopted where as the reality is that this is technology that was required by legislation even last century.
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I would suggest that the title of this video is very misleading. The IEC61000 EMC legislative framework has been in place since the 20th century. The mains harmonic requirements have been revised to make the standard tougher- I think that the latest standards version is something like the 4th revision.
The title of this video suggests that this is a technology that is going to be adopted where as the reality is that this is technology that was required by legislation even last century.
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chillydickie
Most devices mowadays use 5v, 12v and 18-21v range. Would be great you could make video about creating low voltage rails or power supplies for this. e. g. router + modem should really just use one power supply ( and relating to this video, with pfc. Another place would be laptops + monitors + peripherals. Was thinking it would be awesome to have something like 12vDC rail (or higher or lower) available the same way a plug point is standard around the house. Then use sepic to 5v.
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Most devices mowadays use 5v, 12v and 18-21v range. Would be great you could make video about creating low voltage rails or power supplies for this. e. g. router + modem should really just use one power supply ( and relating to this video, with pfc. Another place would be laptops + monitors + peripherals. Was thinking it would be awesome to have something like 12vDC rail (or higher or lower) available the same way a plug point is standard around the house. Then use sepic to 5v.
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Bhagath
The common household consists of lagging power factor due to at least there being a fridge, ceiling fans, exhaust fans or an AC all of which require reactive power to operate. The most simple way to deal with that is to connect a mains voltage rated capacitor of 1kvar or more as required parallel to the mains breaker.
In most skyscraper/ big buildings it is mandatory to place an APFC Panel board to monitor and control power factor between -0. 96 to +0. 96
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The common household consists of lagging power factor due to at least there being a fridge, ceiling fans, exhaust fans or an AC all of which require reactive power to operate. The most simple way to deal with that is to connect a mains voltage rated capacitor of 1kvar or more as required parallel to the mains breaker.
In most skyscraper/ big buildings it is mandatory to place an APFC Panel board to monitor and control power factor between -0. 96 to +0. 96
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nin1ten1do
well ya one BIG PFC POG mahsine inside a HOME CONECTION SPOT: :. but. well i not gona spend money for such a stuff. for more. from small powerbrick with PFC. man. can you inagine a MONEY DRAG INPUT from makers? who gona pay for it? beter spend some on electricity instead of pay for mashine what make revenue +15years. on small powerbrick. pasive one is OK. fitlers help too. this is not suitable for ALL electonics. specialy for some with SYMETRIC PSU.
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well ya one BIG PFC POG mahsine inside a HOME CONECTION SPOT: :. but. well i not gona spend money for such a stuff. for more. from small powerbrick with PFC. man. can you inagine a MONEY DRAG INPUT from makers? who gona pay for it? beter spend some on electricity instead of pay for mashine what make revenue +15years. on small powerbrick. pasive one is OK. fitlers help too. this is not suitable for ALL electonics. specialy for some with SYMETRIC PSU.
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Caffeinated
Oh yeah, I remember when learning about the power triangle (apparent power is a vector made from real and reactive power) when working with 3 phase AC. When you want to compensate for inductive loads generating unwanted reactive power, we simply put a calculated capacitor in parallel to it. But I didn't know it was such a huge deal with DC appliances. I actually never thought chargers weren't SMPSs for the most part and were MUCH more rudimentary.
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Oh yeah, I remember when learning about the power triangle (apparent power is a vector made from real and reactive power) when working with 3 phase AC. When you want to compensate for inductive loads generating unwanted reactive power, we simply put a calculated capacitor in parallel to it. But I didn't know it was such a huge deal with DC appliances. I actually never thought chargers weren't SMPSs for the most part and were MUCH more rudimentary.
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George
Congratulation for your video, extremely interesting, as I saw from your diagram, the last blue dot, seems at 64 VA for 50 watts, that is pretty close to 82% efficiency which is the theoretical efficiency for converting AC to DC. Can you give us the exact numbers. Have you made any video regarding the efficiency of the power chargers of the electric cars to show us how much energy is wasted on the charger during a car charging;
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Congratulation for your video, extremely interesting, as I saw from your diagram, the last blue dot, seems at 64 VA for 50 watts, that is pretty close to 82% efficiency which is the theoretical efficiency for converting AC to DC. Can you give us the exact numbers. Have you made any video regarding the efficiency of the power chargers of the electric cars to show us how much energy is wasted on the charger during a car charging;
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