ir2110 bootstrap capacitor calculation

[abc_de]

Thanks for your unforgettable support I will study and work

 

[Electro nS]

Hello
I am trying to build 3 phase inverter using pic18f4431 mcu, pwm frequency =16khz
Power circuit consist ir2110 mosfet driver, irf 840 as switching device.
I am facing problem while calculate bootstrap capacitor value.
VDD=5VOLTS, VCC=12VOLT, DC BUS VOLTAGE=342
Please any one suggest me what should be right value for bootstrap capacitor. I shall be very thankful.

i can give u equations and how to find that out , but i will talk too much and it has been asked 1million times before .

So my recommendation for this circuit use 1uF cermaic rated to above bus voltage example 400v

hope this helps :-D

 

[abc_de]

Hello
Yes I have an equation for bootstrap capacitor calculation but many of parameters are out of my mind. :thinker:
Presently I am using 3.3uf/63volt and its working fine.
You mean I have to use 1uf/400volt ??? is 63volts is low value of capacitor.

 

[red_alert]

The voltage across bootstrap capacitor does not exceed Vcc voltage (12V typically) so 63V is safe enough. If you're using an electrolytic capacitor (3.3uF) then it's better to put a ceramic one (0.1uF) in parallel.

 

[Electro nS]

Hello
Yes I have an equation for bootstrap capacitor calculation but many of parameters are out of my mind. :thinker:
Presently I am using 3.3uf/63volt and its working fine.
You mean I have to use 1uf/400volt ??? is 63volts is low value of capacitor.

sorry i meant 40v . i should be higher than Vcc not vbus ,

 

[abc_de]

thank you so much i will update very soon

 

[abc_de]

hello
red_alert and all
i had follow the spwm technique for single pahse inverter.
please suggest me i am going right or any suggestion for improvement


https://obrazki.elektroda.pl/7991531500_1424017629.jpg
https://obrazki.elektroda.pl/1229176100_1424017631.png
https://obrazki.elektroda.pl/6458394000_1424017632.png

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i am following the

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these are output wave forms

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[red_alert]

The wave forms look OK (though they're pretty unclear).

Anyway, you have to check that while one low-side switch is kept in the ON state, the other leg high-side switch is following the sine PWM signal (with an ascending then descending duty cycle) and the corresponding low-side switch is driven by a complementary signal (don't forget about dead times though).

 

[Electro nS]

hello
red_alert and all
i had follow the spwm technique for single pahse inverter.
please suggest me i am going right or any suggestion for improvement


https://obrazki.elektroda.pl/7991531500_1424017629.jpg
https://obrazki.elektroda.pl/1229176100_1424017631.png
https://obrazki.elektroda.pl/6458394000_1424017632.png

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i am following the View attachment 114295

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View attachment 114297
these are output wave forms

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View attachment 114298View attachment 114299

these results are made by isis proteus right ? why donot u try orcad pspice simulation it is more accurate and realistic . otherwise the results seem normal , but u need to try the circuit and see real life measurments .