Why do motor drives have multiple bus capacitors of small value capacitance instead of a single bus capacitor of large value?Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values?Can I replace capacitor with multiple lower value capacitors in filter?Why don't we use capacitors containing multiple kinds of dielectric in a single package?Bulk Capacitance inrush current limiting solutionsProtecting a coin cell from high current spikes - using a capacitor or not?Why do some devices use electrolytic capacitors instead of ceramics for small value components?
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Why do motor drives have multiple bus capacitors of small value capacitance instead of a single bus capacitor of large value?
Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values?Can I replace capacitor with multiple lower value capacitors in filter?Why don't we use capacitors containing multiple kinds of dielectric in a single package?Bulk Capacitance inrush current limiting solutionsProtecting a coin cell from high current spikes - using a capacitor or not?Why do some devices use electrolytic capacitors instead of ceramics for small value components?
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All professional DC, BLDC or PMSM motor controllers that I have seen (Sevcon, etc) have large numbers of DC bus capacitors connected in parallel. Their capacitances range around 100uF - 220uF. Wouldnt a single capacitor of large value like 4700uF or 10000uF be more convenient? Is it because of the large surge current whenever these controllers are connected to batteries or other high current power sources?
capacitor motordriver
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add a comment |
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All professional DC, BLDC or PMSM motor controllers that I have seen (Sevcon, etc) have large numbers of DC bus capacitors connected in parallel. Their capacitances range around 100uF - 220uF. Wouldnt a single capacitor of large value like 4700uF or 10000uF be more convenient? Is it because of the large surge current whenever these controllers are connected to batteries or other high current power sources?
capacitor motordriver
asked 8 hours ago
WinnerWinner
262 bronze badges
New contributor
Winner is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
All professional DC, BLDC or PMSM motor controllers that I have seen (Sevcon, etc) have large numbers of DC bus capacitors connected in parallel. Their capacitances range around 100uF - 220uF. Wouldnt a single capacitor of large value like 4700uF or 10000uF be more convenient? Is it because of the large surge current whenever these controllers are connected to batteries or other high current power sources?
capacitor motordriver
asked 8 hours ago
WinnerWinner
262 bronze badges
New contributor
Winner is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
All professional DC, BLDC or PMSM motor controllers that I have seen (Sevcon, etc) have large numbers of DC bus capacitors connected in parallel. Their capacitances range around 100uF - 220uF. Wouldnt a single capacitor of large value like 4700uF or 10000uF be more convenient? Is it because of the large surge current whenever these controllers are connected to batteries or other high current power sources?
capacitor motordriver
capacitor motordriver
asked 8 hours ago
WinnerWinner
262 bronze badges
New contributor
Winner is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 8 hours ago
WinnerWinner
262 bronze badges
New contributor
Winner is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 8 hours ago
WinnerWinner
262 bronze badges
New contributor
Winner is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 8 hours ago
WinnerWinner
262 bronze badges
asked 8 hours ago
WinnerWinner
262 bronze badges
262 bronze badges
New contributor
Winner is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Winner is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
$begingroup$
Sure having enough capacitance is one parameter. But capacitors have series resistance which limits how much peak current can be drawn from a capacitor. Capacitors also have series inductance which limits how fast you can get the peak current out. Having multiple smaller capacitors in parallel reduces both series resistance and inductance.
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
$endgroup$
$begingroup$
Maybe you should add that big capacitors have more inductance than small ones, so a bunch of small caps whose total capacitance equals that of a single larger cap will have lower overall inductance than the single, larger cap.
$endgroup$
– DKNguyen
2 hours ago
add a comment |
$begingroup$
Higher ripple current capability, lower ESR and sometimes better form factor (eg. shorter) to fit in a convenient spot in the enclosure are likely reasons.
More surface area of the capacitor means more power dissipation capability, all other things being equal.
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
$endgroup$
add a comment |
$begingroup$
The capacitors help in filtering and decoupling noise. But each single value of capacitor is only good at one particular frequency. It has least ESR (higher ability to mitigate noise) Using a range of values provides that good filtering ability over wide frequency range.
Reduced Heating due to ESR.
As the ripple currents flow through the capacitors to and fro, the ESR opposes the current flow (similar to resistor). The higher ESR means higher power dissipation (as heat). This effectively raises the temperature of the capacitors. Higher the temperature lower the capacitance they can provide. Hence, low ESR over multiple frequency band is one desired parameter which can be effectively received by combining multiple capacitors than one single bug capacitor.
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
$endgroup$
$begingroup$
Where did you get that impedance graph? It doesn't actually work out that way where you always get the capacitor with the best performance being dominant. There are anti-resonance spikes formed by the interactions of the LC circuit introduced by each capacitor.
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
electronics.stackexchange.com/questions/320363/…
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
@DKNguyen I wanted to only present benefit of sharing multiple of capacitors so that the effective impedance is less. I agree it comes with side effect of antiresonance too.let me not confuse. Will remove it.
$endgroup$
– Umar
7 hours ago
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Sure having enough capacitance is one parameter. But capacitors have series resistance which limits how much peak current can be drawn from a capacitor. Capacitors also have series inductance which limits how fast you can get the peak current out. Having multiple smaller capacitors in parallel reduces both series resistance and inductance.
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
$endgroup$
$begingroup$
Maybe you should add that big capacitors have more inductance than small ones, so a bunch of small caps whose total capacitance equals that of a single larger cap will have lower overall inductance than the single, larger cap.
$endgroup$
– DKNguyen
2 hours ago
add a comment |
$begingroup$
Sure having enough capacitance is one parameter. But capacitors have series resistance which limits how much peak current can be drawn from a capacitor. Capacitors also have series inductance which limits how fast you can get the peak current out. Having multiple smaller capacitors in parallel reduces both series resistance and inductance.
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
$endgroup$
$begingroup$
Maybe you should add that big capacitors have more inductance than small ones, so a bunch of small caps whose total capacitance equals that of a single larger cap will have lower overall inductance than the single, larger cap.
$endgroup$
– DKNguyen
2 hours ago
add a comment |
$begingroup$
Sure having enough capacitance is one parameter. But capacitors have series resistance which limits how much peak current can be drawn from a capacitor. Capacitors also have series inductance which limits how fast you can get the peak current out. Having multiple smaller capacitors in parallel reduces both series resistance and inductance.
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
$endgroup$
Sure having enough capacitance is one parameter. But capacitors have series resistance which limits how much peak current can be drawn from a capacitor. Capacitors also have series inductance which limits how fast you can get the peak current out. Having multiple smaller capacitors in parallel reduces both series resistance and inductance.
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
answered 8 hours ago
JustmeJustme
6,8402 gold badges7 silver badges19 bronze badges
6,8402 gold badges7 silver badges19 bronze badges
$begingroup$
Maybe you should add that big capacitors have more inductance than small ones, so a bunch of small caps whose total capacitance equals that of a single larger cap will have lower overall inductance than the single, larger cap.
$endgroup$
– DKNguyen
2 hours ago
add a comment |
$begingroup$
Maybe you should add that big capacitors have more inductance than small ones, so a bunch of small caps whose total capacitance equals that of a single larger cap will have lower overall inductance than the single, larger cap.
$endgroup$
– DKNguyen
2 hours ago
$begingroup$
Maybe you should add that big capacitors have more inductance than small ones, so a bunch of small caps whose total capacitance equals that of a single larger cap will have lower overall inductance than the single, larger cap.
$endgroup$
– DKNguyen
2 hours ago
$begingroup$
Maybe you should add that big capacitors have more inductance than small ones, so a bunch of small caps whose total capacitance equals that of a single larger cap will have lower overall inductance than the single, larger cap.
$endgroup$
– DKNguyen
2 hours ago
add a comment |
$begingroup$
Higher ripple current capability, lower ESR and sometimes better form factor (eg. shorter) to fit in a convenient spot in the enclosure are likely reasons.
More surface area of the capacitor means more power dissipation capability, all other things being equal.
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
$endgroup$
add a comment |
$begingroup$
Higher ripple current capability, lower ESR and sometimes better form factor (eg. shorter) to fit in a convenient spot in the enclosure are likely reasons.
More surface area of the capacitor means more power dissipation capability, all other things being equal.
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
$endgroup$
add a comment |
$begingroup$
Higher ripple current capability, lower ESR and sometimes better form factor (eg. shorter) to fit in a convenient spot in the enclosure are likely reasons.
More surface area of the capacitor means more power dissipation capability, all other things being equal.
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
$endgroup$
Higher ripple current capability, lower ESR and sometimes better form factor (eg. shorter) to fit in a convenient spot in the enclosure are likely reasons.
More surface area of the capacitor means more power dissipation capability, all other things being equal.
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
answered 8 hours ago
Spehro PefhanySpehro Pefhany
222k5 gold badges177 silver badges465 bronze badges
222k5 gold badges177 silver badges465 bronze badges
add a comment |
add a comment |
$begingroup$
The capacitors help in filtering and decoupling noise. But each single value of capacitor is only good at one particular frequency. It has least ESR (higher ability to mitigate noise) Using a range of values provides that good filtering ability over wide frequency range.
Reduced Heating due to ESR.
As the ripple currents flow through the capacitors to and fro, the ESR opposes the current flow (similar to resistor). The higher ESR means higher power dissipation (as heat). This effectively raises the temperature of the capacitors. Higher the temperature lower the capacitance they can provide. Hence, low ESR over multiple frequency band is one desired parameter which can be effectively received by combining multiple capacitors than one single bug capacitor.
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
$endgroup$
$begingroup$
Where did you get that impedance graph? It doesn't actually work out that way where you always get the capacitor with the best performance being dominant. There are anti-resonance spikes formed by the interactions of the LC circuit introduced by each capacitor.
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
electronics.stackexchange.com/questions/320363/…
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
@DKNguyen I wanted to only present benefit of sharing multiple of capacitors so that the effective impedance is less. I agree it comes with side effect of antiresonance too.let me not confuse. Will remove it.
$endgroup$
– Umar
7 hours ago
add a comment |
$begingroup$
The capacitors help in filtering and decoupling noise. But each single value of capacitor is only good at one particular frequency. It has least ESR (higher ability to mitigate noise) Using a range of values provides that good filtering ability over wide frequency range.
Reduced Heating due to ESR.
As the ripple currents flow through the capacitors to and fro, the ESR opposes the current flow (similar to resistor). The higher ESR means higher power dissipation (as heat). This effectively raises the temperature of the capacitors. Higher the temperature lower the capacitance they can provide. Hence, low ESR over multiple frequency band is one desired parameter which can be effectively received by combining multiple capacitors than one single bug capacitor.
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
$endgroup$
$begingroup$
Where did you get that impedance graph? It doesn't actually work out that way where you always get the capacitor with the best performance being dominant. There are anti-resonance spikes formed by the interactions of the LC circuit introduced by each capacitor.
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
electronics.stackexchange.com/questions/320363/…
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
@DKNguyen I wanted to only present benefit of sharing multiple of capacitors so that the effective impedance is less. I agree it comes with side effect of antiresonance too.let me not confuse. Will remove it.
$endgroup$
– Umar
7 hours ago
add a comment |
$begingroup$
The capacitors help in filtering and decoupling noise. But each single value of capacitor is only good at one particular frequency. It has least ESR (higher ability to mitigate noise) Using a range of values provides that good filtering ability over wide frequency range.
Reduced Heating due to ESR.
As the ripple currents flow through the capacitors to and fro, the ESR opposes the current flow (similar to resistor). The higher ESR means higher power dissipation (as heat). This effectively raises the temperature of the capacitors. Higher the temperature lower the capacitance they can provide. Hence, low ESR over multiple frequency band is one desired parameter which can be effectively received by combining multiple capacitors than one single bug capacitor.
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
$endgroup$
The capacitors help in filtering and decoupling noise. But each single value of capacitor is only good at one particular frequency. It has least ESR (higher ability to mitigate noise) Using a range of values provides that good filtering ability over wide frequency range.
Reduced Heating due to ESR.
As the ripple currents flow through the capacitors to and fro, the ESR opposes the current flow (similar to resistor). The higher ESR means higher power dissipation (as heat). This effectively raises the temperature of the capacitors. Higher the temperature lower the capacitance they can provide. Hence, low ESR over multiple frequency band is one desired parameter which can be effectively received by combining multiple capacitors than one single bug capacitor.
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
edited 7 hours ago
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
answered 7 hours ago
UmarUmar
4,9533 gold badges12 silver badges35 bronze badges
4,9533 gold badges12 silver badges35 bronze badges
$begingroup$
Where did you get that impedance graph? It doesn't actually work out that way where you always get the capacitor with the best performance being dominant. There are anti-resonance spikes formed by the interactions of the LC circuit introduced by each capacitor.
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
electronics.stackexchange.com/questions/320363/…
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
@DKNguyen I wanted to only present benefit of sharing multiple of capacitors so that the effective impedance is less. I agree it comes with side effect of antiresonance too.let me not confuse. Will remove it.
$endgroup$
– Umar
7 hours ago
add a comment |
$begingroup$
Where did you get that impedance graph? It doesn't actually work out that way where you always get the capacitor with the best performance being dominant. There are anti-resonance spikes formed by the interactions of the LC circuit introduced by each capacitor.
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
electronics.stackexchange.com/questions/320363/…
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
@DKNguyen I wanted to only present benefit of sharing multiple of capacitors so that the effective impedance is less. I agree it comes with side effect of antiresonance too.let me not confuse. Will remove it.
$endgroup$
– Umar
7 hours ago
$begingroup$
Where did you get that impedance graph? It doesn't actually work out that way where you always get the capacitor with the best performance being dominant. There are anti-resonance spikes formed by the interactions of the LC circuit introduced by each capacitor.
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
Where did you get that impedance graph? It doesn't actually work out that way where you always get the capacitor with the best performance being dominant. There are anti-resonance spikes formed by the interactions of the LC circuit introduced by each capacitor.
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
electronics.stackexchange.com/questions/320363/…
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
electronics.stackexchange.com/questions/320363/…
$endgroup$
– DKNguyen
7 hours ago
$begingroup$
@DKNguyen I wanted to only present benefit of sharing multiple of capacitors so that the effective impedance is less. I agree it comes with side effect of antiresonance too.let me not confuse. Will remove it.
$endgroup$
– Umar
7 hours ago
$begingroup$
@DKNguyen I wanted to only present benefit of sharing multiple of capacitors so that the effective impedance is less. I agree it comes with side effect of antiresonance too.let me not confuse. Will remove it.
$endgroup$
– Umar
7 hours ago
add a comment |
Winner is a new contributor. Be nice, and check out our Code of Conduct.
Winner is a new contributor. Be nice, and check out our Code of Conduct.
Winner is a new contributor. Be nice, and check out our Code of Conduct.
Winner is a new contributor. Be nice, and check out our Code of Conduct.
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