Alternative Energy (Solar, Wind, Grid Stabilization)
In Alternative Energy systems, Power Ring Film Capacitors™ are the DC Link Capacitors used in inverters and in Power Conditioning Filters. Power Ring Film Capacitors™ offer long-term reliability and significantly reduce costly maintenance and repairs while maximizing the energy conversion process. Typical voltages range from 200V – 1500Vdc and ripple currents range from 40 – 500 Arms at 10 – 100khz switching frequencies.
In many applications, Aluminum Electrolytics were used extensively, however, as voltages and ripple currents rise, these may not be the best choice any longer for reliable use. In fact, even at current voltages, the Aluminum Electrolytics are considered the most unreliable component in the system and many system designers would like to eliminate their use. The linked paper by the US NREL (pdf link) has very specific reliability data on typical capacitors used for Alternative Energy systems.
The Power Ring Film Capacitor™ has much lower losses than a conventional array (see graph) and therefore has much less cooling requirement and can provide for significantly greater ripple current filtering in less space, using less weight, and costing less money. The example below demonstrates an electric drivetrain automobile application but the results are the same in alternative energy applications.
Our technical team has presented numerous papers on the use of the Power Ring Film Capacitor™ in the DC Link Application including optimum ways of connecting the capacitor to the switch bus. Please check them out on our technical papers/presentations page.
DoE Research Goal of High Temperature, Long-lifetime DC Link Film Capacitors
SBE has completed its DoE Phase I SBIR research on the topic of High Temperature, Low Cost Ripple Current Capacitors. The Phase II goal of this research is to produce a DC Link Film Capacitor which can meet the goals of a 200Arms ripple current, 450V system meeting 10,000 hour minimum lifetime requirements. This lifetime is up to 5 times longer than many Aluminum Electrolytic capacitor banks currently in the field.
The following documents present an update on this research:
- SBIR Update (pdf link)
- Status Report and Technology Overview of Leading Edge Development In the field of Increased Power Density Inverter Technology and the use of 105°C Engine Coolant for the DC Link Capacitor (pdf link)
Changing a Common Design Criteria in the Industry
Until now, it has been commonly believed that in order to achieve significant ripple current increases in a DC Link Capacitor bank, a designer needed to greatly increase overall capacitance. This often greatly increased size, weight, and cost.
As you can see, with SBE’s Power Ring Film Capacitor™, this is no longer the case. For the first time, the capacitor has been “designed for increased current” rather than the typical approach of adding more and more capacitors until the current rating is achieved. The system results can be remarkable. Please contact us for more information on how to best take advantage of these design characteristics.
Obtaining greatly increased performance using a conventional system footprint
Many customers use the Power Ring Film Capacitor as a drop in replacement for a bank of Aluminum Electrolytic or conventional Film Capacitors.
Here are some of the alternative energy applications where it is used:
- Inverter DC Link Capacitor
- Inverter Snubber Capacitor
- High Energy Storage Controller Capacitors
- Utility Grade Inverter Capacitors
- High Voltage field control capacitors
- Corona Free Capacitors
And here are some actual examples:
- A 10µF 8000Vdc capacitor designed for survivability of lighting or grid spike event.
Check out specification details (pdf link). - A 75µF capacitor in a 1200 Vdc inverter. Capacitor is designed for 50 Arms continuous service with extreme fault current survivability.
Check out specification details (pdf link).
Contact our application engineering team to discuss your requirements.