Long lifetime

The DC bus capacitors provide an energy store and de-coupling buffer between the supply network and the load
side converter. The high value of the capacitors almost eliminates the voltage ripple and stabilizes the DC bus
voltage, suppressing disturbances caused by fluctuations of the load and supply side harmonics and switching
transients.Traditionally, the capacitors used for the DC bus have been of aluminium electrolytic type as the technology is mature and relatively low cost and also achieves a high energy density.

Disadvantages of electrolytic capacitors
However, electrolytic capacitors suffer from some disadvantages:
∙ Limited ability to handle large ripple current.
∙ Limited voltage rating and ability to handle voltage surges. It is necessary to connect capacitors in series and use voltage-sharing resistors, increasing system design complexity and reducing overall reliability.
∙ Limited lifetime.
∙ Unsuitability for long-term storage as spare parts.
∙ Failure modes may result in collateral damage to other components.

Advantages of metalized film capacitors
The RMVC 5100 uses metalized film capacitors which have the following advantages, despite having a lower power
density:
∙ Limited ability to handle large ripple current.
∙ Limited voltage rating and ability to handle voltage surges. It is necessary to connect capacitors in series and use
voltage-sharing resistors, increasing system design complexity and reducing overall reliability.
∙ Limited lifetime.
∙ Unsuitability for long-term storage as spare parts.
∙ Failure modes may result in collateral damage to other components.

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