Yokogawa has moved to a modular architecture to handle the growing number of complex applications that are emerging in power testing, ranging from spotting ‘vampire power’ in AC adaptors through to arrays of inverters in solar generators.
The WT5000 marks an increase in capture rates into the megahertz region with a top sample rate of 10Msample/s and a bandwidth of 5MHz. "It's fifty times faster than the previous model, the WT3000," said Anoop Gangadharan, product marketing manager.
Yokogawa expects to have to go further over time to handle the needs of designers working with processes such as gallium nitride. These compound semiconductors favour switching speeds of tens of megahertz using topologies such as matrix conversion. At the moment, these designs are supported using high-speed oscilloscope and specialized probes. As GaN designs remain comparatively rare, particularly with novel topologies, Gangadharan said: “This unit will satisfy market demands for a good few years.”
Although the WT5000 is the same size as existing models in Yokogawa’s WT series, the new instrument takes a variety of plug-in modules that can provide up to seven input channels. The company expects this will let a single unit handle test applications that previously could only have been measured by synchronizing several separate instruments.
However, recognizing that designs in electric vehicles and renewables generation can involved monitoring multiple power phases and motor positions accurately, the company supplies dedicated clock-interface modules that synchronise up to four of the instruments. A set of internal synchronization functions make it possible to align measurements based on a number of different signal edges.
For motor evaluation inputs can include torque sensors and rotary encoders to accurately measure mechanical force and rotor position. For electrical power analysis, the WT5000 can carry out two harmonic measurement functions simultaneously, each at up the 500th order and up to 300kHz for the fundamental waveform. This makes it possible to measure the carrier frequency component from the rotational speed of the motor in the inverter drive and also to check the influence of the carrier frequency on the motor drive.