Attain Greater Accuracy When Measuring the Efficiency of Increasingly High-Current, High-Speed EV/HEV Inverters
December 19, 2018 – Nagano, Japan
Hioki is please do announce the release of the AC/DC Current Sensor CT6875 (rated for 500 A) and CT6876 (rated for 1000 A). The pair of pass-through current sensors deliver significant improvements in frequency band and noise resistance over their predecessors (the AC/DC Current Sensor 9709 and CT6865), making them ideally suited for use in applications such as measuring the efficiency of the increasing high-current, high-speed inverters that are used in today’s electric and hybrid vehicles (EVs and HEVs).
The automotive market’s global transition to EVs began gathering momentum during the second half of 2017. Most of the first EVs and HEVs to be introduced were compact vehicles whose development necessitated measuring currents of around 200 A, but the moveto bring electric drivetrains to larger vehicles has led to demand for the ability to measure currents of 500 A and higher. In addition, adoption of SiC/GaN elements*1 in inverters is driving increases in power conversion unit switching speeds (on/off cycle speeds) and efficiency. Consequently, the industry demands current sensors that can measure larger currents with greater precision over a wider band of frequencies and in a broader range of operating temperatures than ever before.
Legacy Hioki sensors capable of measuring currents of 500 A and greater include the AC/DC Current Sensor 9709 (rated for 500 A) and CT6865 (rated for 1000 A), but those devices offered insufficient performance to fulfill the required specifications. To address this shortfall, Hioki developed the CT6875 and CT6876 by improving the performance of those two products.
*1 Silicon carbide (SiC) and gallium nitride (GaN) are being used as replacements for silicon in the manufacture of next-generation semiconductors.
* Evaluation, design, and development of inverters and batteries for EVs and HEVs
* Evaluation, design, and development of power conditioners for solar power systems
1. Broad frequency band
The CT6875 provides a frequency band of 2 MHz, which is 20 times that of its predecessor (the 9709), while the CT6876 provides a band of 1.5 MHz, which is 75 times that of its predecessor (the CT6865).
2. Significantly improved noise resistance, even at high frequencies
Enhanced shielding enables the effects of noise such as common-mode voltage to be significantly reduced in current measurement at high frequencies.