Research into improving the conversion of AC power lines to high-voltage direct current (HVDC) in power grids is under way at the Department of Electrical Engineering's GISEL research group at Spain's UPV/EHU-University of the Basque Country.
According to the researchers, direct current lines are less costly to build and have lower power transmission losses than AC lines. Since most electricity currently is transmitted by AC, the researchers hope to make it easier (and less costly) to facilitate conversion from AC to HVDC in applications and locations where the latter would prove beneficial.
As a result, the GISEL group is working on new voltage source converter technology (see image below), as well as ways to make the features of three-conductor AC and two-conductor DC lines more compatible. The researchers foresee HVDC grids eventually coexisting with AC grids.
A basic three-phase, two-level voltage-source converter for HVDC.
Based on its teardown and research services, ABI Research reports that smartwatches such as the Samsung Galaxy Gear and the Z-Watch are being designed with smartphone chipsets, rather than parts optimized for wearable devices. According to the research firm, no company has developed an optimal wearable solution; the current products offer less-than-optimal battery life, size, and user experience.
In product news, Linear Technology has announced a programmable voltage supervisor that monitors up to six voltage rails from 0.2 to 13.9 V. The LTC2933 offers I2C adjustable undervoltage and overvoltage trip points and features a guaranteed threshold accuracy of ±1%. The company also introduced the LTM2987 16-channel µModule PMBus power system manager, which controls and monitors supply outputs with ±0.25% voltage accuracy.
Maxim Integrated has listed details of an eight-channel simultaneous-sampling analog front-end measurement solution for three-phase power monitoring applications. The Petaluma (MAXREFDES30#) subsystem reference design includes hardware, firmware, design files, and lab measurements. It features eight 250-ksample/sec, 16-bit simultaneous-sampling analog-input channels that accept ±10-V input signals.
Power Sources Unlimited has announced a new family of high-performance DC/DC converters that meet IEC/EN 60601-1 3rd edition and 2x MOPP medical approvals. The DIP-24 packaged THM-WI series is available in 3-W (THM 3WI), 6-W (THM 6WI) and 10-W (THM 10WI) versions.
A new series of chokes from Pulse Electronics integrates common-mode and differential-mode chokes into one component. The PA4040 integrated choke has a 31 x 24.9-mm footprint and a DC resistance of between 32 and 245 mΩ.
Finally, Vishay Intertechnology has introduced a new hi-rel series of surface-mount solid tantalum molded chip capacitors for military and aerospace applications. The new Tantamount Vishay Sprague T42 series combines a built-in fuse with capacitance values to 470 µF, voltage ratings to 75 VDC, and ESR down to 80 mΩ at +25°C and 100 kHz.