Expo presenter addresses automotive motor and inverter test

Novi, MI. Optimization of electric motors and inverters in electric vehicle drivetrains requires continuous and synchronous acquisition of electrical and mechanical raw data for review, verification, and analysis, according to Mike Hoyer, applications engineer at HBM Test and Measurement. Speaking at the Automotive Testing Expo here October 29, he said that unfortunately, the standard methods for efficiency testing on electric drivetrains provide only inadequate results and are unable to provide complete, usable data in response to dynamic load changes.

Traditional methods, he said, address steady-state conditions, but what is needed is a way to safely and accurately make continuous and synchronous measurements of parameters such as voltage, current, torque, speed, temperature, and vibration—all leading to improved electric drivetrain efficiency—from the current 50 to 60% battery-to-road efficiency.

Typically, Hoyer said, engineers use DMMs, power analyzers, and current transformers to measure inverter electrical parameters and, for instance, torque transducers to measure motor mechanical parameters. However, with it is difficult to synchronize the measurements, continuous raw data is not available for further analysis, and measurement algorithms aren’t well documented—often leading to anomalous results such as efficiency being greater than 1.

He presented a wish list of what would be needed to solve the problems of traditional techniques: simple system configuration; reliable acquisition and simultaneous sampling of electrical and mechanical parameters; the ability to record acquired data to disk in a single, open file format; and modern software interfaces. HBM’s eDrive, he concluded, facilitates the test of electric motors and drives by enabling the dynamic, synchronous measurement of voltage, current, torque, speed and other parameters simultaneously and continuously at high sample rates, especially during dynamic load changes.

More in Instrumentation