Jason Lomberg, North American Editor, PSD
Every design must invariably go through a testing phase, which makes Test & Measurement a universal industry concern. It also makes T&M an extremely diverse topic, and the September “Special Report” series covers a wide array of subjects, including digital PWM control technology, high-power test equipment for electric vehicle battery packs, power rail probes, oscilloscope probes, accurate power measurement, and battery diagnosis.
We begin with a topic familiar to all PSD readers -- accurate power measurement (the key to energy efficiency). Without it, and since power is such a pervasive issue, no product can reach market (or advance from conception to any semblance of reality).
“An engineer’s power measurement needs can vary or evolve across the development cycle. For example, isolated tests of individual components in early development stages may only need waveform analysis at limited accuracy,” says Yokogawa’s Anoop Gangadharan.
“But when a multicomponent system needs to be tested the system has to be looked at as a whole, calling for sophisticated multichannel, multi-parameter measurements.”
Pacific Power Source delves into digital PWM control technology which, in turn, has enabled higher efficiencies and smaller packaging of power electronics. This new “digital domain control architecture” offers several unique features and functions with programmable power source designs that are smaller and lighter than their predecessors.
Meanwhile, Adaptive Power Systems’ Herman van Eijkelenburg discusses using high-power test equipment to increase the battery capacity of electric vehicles while also improving electric drive train efficiencies.
“Forecasts on future sales of all electric vehicles are pointing to a growing need for large battery packs,” notes van Eijkelenburg. “These batteries must be carefully designed and thoroughly tested to meet customer expectations for driving range, durability and above all, safety. Without the right tools and equipment, testing of these batteries will be inadequate to meet these goals.”
Sticking with batteries, Andreas Mangler, Olfa Kanoun, and Thomas Günther detail a new procedure from Chemnitz University of Technology for diagnosing the state of health (SoH) and the remaining useful life (RUL) of Li-ion batteries. “The battery’s state of health has a direct effect on the capacity of the overall system,” the authors point out. “In safety-relevant applications, such as backup systems or mobile medical applications, it is essential to know that the battery will supply the required energy when it is actually needed.”
Joel Woodward, with Rohde & Schwarz, describes the advantages of power rail probes over traditional oscilloscope solutions for power integrity measurements. Normal oscilloscopes are hindered by measurement noise (exacerbated by the probe, which adds additional noise to the measurement), and as Woodward points out, “The higher the attenuation of the probe, the more noise.”
“All probes contribute to a dramatic increase in overall measurement noise, except for power rail probes,” he says.
On the other hand, oscilloscope probes can be useful for voltage and timing measurements (including jitter and noise measurements), and in “Probing Tips for High-Performance, Low-Power Circuits,” Tektronix's Andy Heltborg notes that “while connecting to the low-power device under test might be possible with a coaxial cable, many systems require an oscilloscope probe to acquire the signals.”
Enjoy our September issue, and be sure to check out more design tips for Test & Measurement (and other topics) on www.powersystemsdesign.com