Many non-traditional energy sources, such as solar panels, fuel cells, and batteries, supply direct-current (DC) power. This has led to development of DC power systems for a number of applications since conversion to alternating-current (AC) can be eliminated. For example, DC distribution is now used for computer data centers, office buildings, and ship power and propulsion. Though the source, loads, and other components in a DC power system are well understood, there may be interest in innovation with respect to protection schemes since DC systems do not have a zero crossing in its current, and circuit breakers are unable to open up a faulted component without sustaining an arc.

Researchers at the University of California, Davis, have developed an improved redox flow battery (RFB) for intermittent renewable energy applications such as wind, solar, and tidal. The device provides high-density energy storage and transfer without losing capacity over time and frequent replacement as with traditional lithium batteries.

Renewable energy sources such as solar photovoltaics (PV) and wind turbines are used for clean power generation to address the ever-increasing energy consumption. With large-scale integration of renewables, battery storage becomes essential in the grid to meet supply-demand volatility. In these scenarios, direct current (DC) grids offer multiple benefits over alternating current (AC) grids such as, improved efficiency, controllability, reliability and reduced cost. Isolated voltage boost/step-up DC-DC converters are used for interfacing PV and wind energy sources with DC grids and DC-DC converters serve such applications and environments. Existing DC-DC converter designs have known weaknesses. For example, shunt-resonant converter capacitors require a dedicated charging interval in every switching half-cycle, which does not contribute towards energy transfer and results in duty-cycle loss. Since the shunt-resonant capacitor is designed to hold resonant energy sufficient for a rated current condition, resonant energy is fixed for all loading conditions. At reduced loading, reduced resonant energy is sufficient but shunt-configuration has no means to achieve this control. Although this may be mitigated by using two additional switches, this arrangement leads to increased losses and cost. At reduced loading, duty-cycle loss increases significantly because the reduced current results in longer capacitor charging time. This severely restricts the operation range of converter. Smooth current commutation and zero-current-switching (ZCS) are also lost at overload conditions since the capacitor is designed for rated-current condition. The shunt-resonant capacitor is expected to hold its voltage/energy during the operating mode when input inductor charges. However, a leakage path exists through the transformer winding parasitics, which results in capacitor discharge. As a result, the capacitor energy must be overrated to compensate for this loss, which further aggravates all of the aforementioned issues. In another example, series-resonant capacitors must also be charged to a voltage higher than the reflected voltage across the transformer-primary. Peak voltage-rating of primary-side components (e.g., switches and input inductor) is also increased. Series-resonant capacitor also transfers energy to the output during the time interval when resonant current commutation occurs, which requires using capacitors having a higher rating. At reduced loading, the series-resonant capacitor does not have enough voltage to satisfy the resonant condition. Switching frequency may be used as an additional control parameter without using extra switches. Reduction in switching frequency results in increased charging time and hence, higher voltage, while ripple content increases and requires larger filters due to varying switching frequency. Overall, while traditional DC-DC converters like the aforementioned meets some requirements, it may be desirable to have new DC-DC converter approaches to smoothly onboard and operate PV and wind energy production with DC grids.

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Researchers at the University of California, Davis have developed an innovative synthesis approach to achieve high anisotropy L1 FeNi by combining physical vapor deposition and a high speed rapid thermal annealing (RTA).

UCLA researchers have developed an accurate low-profile shear sensing unit that is viable for both gas and liquid flows.

UCLA researchers in the Department of Mechanical and Aerospace Engineering have developed a novel biplane blade configuration that optimizes aero-structural performance for wind turbine blades and other airfoil applications.