Power density

About: Power density is a research topic. Over the lifetime, 9534 publications have been published within this topic receiving 197264 citations. The topic is also known as: volumic power & volume power density.

A 2 kW, single-phase, 7-level, GaN inverter with an active energy buffer achieving 216 W/in3 power density and 97.6% peak efficiency

Abstract: High efficiency and compact single phase inverters are desirable in many applications such as solar energy harvesting and household appliances. This paper presents a 2 kW, 60 Hz, 450 VDC to 240 VRMS power inverter, designed and tested subject to the specifications of the Google/IEEE Little Box Challenge. The inverter features a 7-level flying capacitor multilevel converter, with low-voltage GaN switches operating at 120 kHz, the highest switching frequency to date at this power level. The inverter also includes an active buffer for twice-line-frequency power pulsation decoupling, which reduces the required capacitance by a factor of eight compared to conventional passive decoupling capacitor, while maintaining an efficiency above 99%. The inverter prototype is a self-contained box that achieves a high power density of 216 W/in3 and a peak overall efficiency of 97.6% while meeting the constraints including input current ripple, load transient, thermal and EMC specifications.

Ultrahigh power efficiency operation of common-emitter and common-base HBT's at 10 GHz

Abstract: The DC and RF characteristics of microwave power HBTs are described. Ultrahigh power-added efficiency is reported for AlGaAs-GaAs HBTs operating at 10 GHz in common-emitter (CE) and common-base (CB) modes. A record high 67.8% power-added efficiency with 11.6 dB associated gain was achieved with a CE HBT at a CW output power of 0.226 W, corresponding to a power density of 5.6 W/mm. With a CB HBT, 62.3% power-added efficiency with 11.85 dB gain and 0.385 W total CW power was demonstrated. Power saturation characteristics of CE and CB HBTs are compared. The importance of bias schemes is discussed. High-efficiency operation in near class B mode is described and compared with FET operation. An advantage of HBT over FET is the low leakage current during the off half cycle in class B operation. Stability conditions for CE and CB HBTs are discussed. >

Analysis of Piezoelectric Materials for Energy Harvesting Devices under High-g Vibrations

Abstract: We analyzed the miniaturized energy harvesting devices (each volume within 0.3 cm3) fabricated by using three types of piezoelectric materials such as lead zirconium titanate (PZT) ceramic, macro fiber composite (MFC) and poly(vinylidene fluoride) (PVDF) polymer to investigate the capability of converting mechanical vibration into electricity under larger vibration amplitudes or accelerations conditions (≥1g, gravitational acceleration). All prototypes based on a bimorph cantilever structure with a proof mass were aimed to operate at a vibration frequency of 100 Hz. PZT-based device was optimized and fabricated by considering the resonant frequency, the output power density, and the maximum operating acceleration or safety factor. PVDF- and MFC-prototypes were designed to have same resonant frequency as well as same volume of the piezoelectric materials as the PZT prototype. All three devices were measured to determine if they could generate enough power density to provide electric energy to power a wireless sensor or a microelectromechanical systems (MEMS) device without device failure.

Utility of extracting alpha particle energy by waves

Abstract: The utility of extracting CY particle power, and then diverting this power to fast fuel ions, is investigated. As power is diverted to fast ions and then to ions, a number of effects come into play, as the relative amounts of pressure taken up by electrons, fuel ions and fast CY particles shift. In addition, if the CY particle power is diverted to fast fuel ions, there is an enhanced fusion reactivity because of the non-thermal component of the ion distribution. Some useful expressions for describing these effects are derived, and it is shown that fusion reactors with power density about twice what otherwise might be obtained can be contemplated, so long as a substantial amount of the 01 particle power can be diverted. Interestingly, in this mode of operation, once the electron heat is sufficiently confined, further improvement in confinement is actually not desirable. A similar improvement in fusion power density can be obtained for advanced fuel mixtures such as D-3He, where the power of both the energetic CY particles and the energetic protons might be diverted advantageously.

Method and system for dynamically power budgeting with device specific characterization of power consumption using device driver programs

Abstract: A computer system that provides device specific power characterizations for power control and budgeting functions is disclosed. The device driver programs of the computer system or a power characterizer of the system determines device specific power characterizations for corresponding devices under device specific controlled conditions. The device specific power characterizations are stored in persistent storage for subsequent use by power control and budgeting functions.