Capacitors

North Carolina State University is currently seeking an industry partner to further develop and commercialize the novel High Power Density Switched-Capacitor Converter. Abstract: To tap the wind potential and to run the grid solely on HVDC a DC-DC converter is used to convert the low voltage rectified output of the wind turbine to high voltages.This new family of step-up SC converter can significantly reduce the required filter capacitors in switched-capacitor converter leading to high power density and reduced cost.

This technology provides materials and methods for the production of activated carbons from biochar where such activated carbons have specific area and pore volume characteristics. The activated carbons may be used for any purpose necessitating the need for them such as water purification air-cleaning solvent recovery catalyst supports and as an energy storage form. They may also be useful in the production of a super anode for a super capacitor or battery.

Problem: Electrolytic capacitors and per panel magnetics have limited lifetime and are expensive. Technology: This invention proposes per-panel Maximum Power Point Tracking (MPPT) for widespread solar arrays. A full system approach is presented utilizing switched capacitor multi-level DC-DC and a central ripple-port inverter to replace the multiple inductors used in current PV technology.

Background: Variable frequency inverter drive systems are being used more often for driving electrical machines; these are of particular importance for driving large industrial motors and traction motors for vehicles. However traditional variable frequency drives are limited by high device voltage ratings and poor output waveform quality. Thus multilevel inverters have been considered for such applications because of their improved long-term reliability reduced size improved performance and lower cost.

Background: Power conversion systems that interface between dc and single-phase ac need energy storage to provide buffering between the constant power desired by a dc source or load and the continuously varying power desired for a single-phase ac system. While electrolytic capacitors are generally used to provide high-density energy storage for buffering their limited-life and reliability are a concern. Film capacitors have much longer life and higher reliability but an order of magnitude lower peak energy density.

Background: Testing and characterization of electrochemical energy cells such as microbatteries is critical in the development of battery-powered microelectronics. Discharge and cycle testing of microbatteries may require days or weeks of continuous monitoring and often must be conducted in a closed environment such as a glovebox. Galvanostatic studies are at present the preferred method for characterizing the performance of energy cells but characterization of microbattery performance requires galvanostats with microamp or better resolution.

Background: Currently MnO2 is commonly coated onto current collectors to form very thin films with a thickness of ten to one-thousand nanometers in order to minimize the limitation of poor conductivity. Therefore the relative amount of MnO2 on current collector is always low and does not provide sufficient energy and power density.

This conversion guide is intended to assist with the safe conversion of air conditioning systems to use flammable hydrocarbon (HC) refrigerants. Converting an air conditioning system from a non-flammable to a flammable refrigerant requires special considerations, which are summarised here.

Many storage technologies have been considered in the context of utility-scale energy storage systems. These include:

Research at SDSU has developed a preparation methods for producing functional carbon composites from biochar an abundant byproduct from biofuel production. The carbon composites have shown to possess smart nano-gate properties to achieve electro-field stimuli-responsive control of ions and electrons transfer whichprevents leakage after charging as well as enables a smart control for charging and discharging of supercapacitors or superbatteries.