Photovoltaic inverter capacitor selection standard

How to sizing capacitors for inverter bus link applications?

The first step in sizing capacitors for inverter bus link applications should be to understand how much bus link capacitance is required for a given inverter design. The biggest design limitation for electrolytic capacitors in inverter applications has been the amount of ripple current that the electrolytic capacitor can sustain.

How big should a DC link capacitor be?

With electric vehicles, inverters are typically optimized for two things - power density and efficiency. Thus, DC link should not be any larger than what the requirements call for. The objective of this article is to help you better understand the role of the DC link capacitor and how to properly size it based off your requirements.

What type of capacitor is best for power electronics?

Typically, aluminum electrolytic capacitors are the best option for power electronics applications requiring high capacitance (100’s of μF to Farads), up to 550 Vdc. current capacitor DC Link applications DC Link film caps meet bus voltage applications between 450 – 1300 Vdc. Custom DC Link designs available up

Does Adding capacitance improve the performance of an inverter?

So beyond a certain point, adding capacitance does little to enhance the performance of the inverter. = 308 uF That’s 16 times less capacitance than that of the electrolytic capacitor! Certainly packaging a 308 uF capacitor verses a 5,000uF capacitor makes for a smaller, lighter and more compact design.

What voltage should a capacitor be rated for?

In general, the DC voltage rating of the capacitor should be rated based on the average maximum bus voltage x 1.1 (factor of safety) . E.g. if your 100% SOC battery voltage is 400V, the voltage rating of the capacitor should be 450V or higher.

What is a good voltage rating for a film capacitor?

E.g. if your 100% SOC battery voltage is 400V, the voltage rating of the capacitor should be 450V or higher. The factor of safety can be relatively low for the voltage rating because film capacitors can withstand a DC potential of 1.3 x rated voltage for one minute without damage or breakdown.