DC inverter capacitor

What is a DC link capacitor in a power inverter?

The DC link capacitor is applied from positive to negative after rectification. In a power inverter, a DC link capacitor is placed in parallel with the input to minimize the effects of voltage variations as the load changes. The DC link capacitor also provides a low-impedance path for ripple currents generated by power switching circuits.

How do I choose the best capacitor for a power inverter?

Selection of the best capacitor for a power inverter or other DC link application usually begins with a comparison of the required capacitance and ripple currents. Make sure that the specs you are comparing are referenced to the same operational standards.

Why do inverters need a capacitor?

The capacitor helps maintain the desired voltage level by reducing the ripple generated by the inverter's switching operations. The inverter’s power rating determines how much current is drawn from the DC bus. Higher power ratings require larger capacitors to ensure adequate energy storage and voltage stabilization.

Why does a DC link capacitor have a ripple current ICAP?

We may infer from Figure 2 that the DC link capacitor’s AC ripple current Icap arises from two main contributors: (1) the incoming current from the energy source and (2) the current drawn by the inverter. Capacitors cannot pass DC current; thus, DC current only flows from the source to the inverter, bypassing the capacitor.