voltage and frequency stablization circuit use in automobile

[suryaurza9]

In pwm circuit for bike, 3 wheeler auto, car etc. requirment of 12v dc input power supply.
but in a 3 wheeler auto input supply for pwm is taking form coil which give ac supply.
that supply is rectified by the bridge rectifier.
then problem is created. when high voltage capacitor is used then it provide high voltage but pwm work on 12v dc so we don't used
and when 12v capacitor is used then due to some high frequency ripple the capacitor is damage.
please tell us what we do for frequency stablization.

 

[Harald Kapp]

Showing us a circuit diagram would be great help.

when high voltage capacitor is used then it provide high voltage but pwm work on 12v dc

That is nonsense. The voltage rating of a capacitor states what voltage this capacitor will take without being damaged. It will not generate a high voltage from a lower voltage. A car's electric system is designed for 12V (DC) operation. A capacitor with at least 16V rating (25V is more advisable) should work.

and when 12v capacitor is used then due to some high frequency ripple the capacitor is damage

The damage is probably not due to the high frequency of the ripple but to overvoltage that is higher than the capacitor's rating.
If really high frequency is the problem, a capacitor with low ESR 8equivalent series resistance) is required.

 

[suryaurza9]

frequency stabilization

if we want to stable the frequency in automobile field. what we do?
for example : conversion of wind to electricity. in this field frequency stabilized using dummy load. but in automobile we can't use it because we reduce the losses and increase the efficiency.

 

[Harald Kapp]

A car's electric circuit runs on DC. What kind of "frequency stabilisation" are you talking about?