31 E-Mobility Engineering | January/February 2026 Motor testing | Tech focus bus, GPS and other signals to conduct a structural evaluation of a vehicle. Recording the electrical voltages and currents coming from an electric machine can provide insights into vehicle dynamics. The introduction of electric power measurements allows correlation of powertrain values to structural dynamics and noise, vibration and harshness (NVH). Example measurements illustrate the correlation of motor power measurements to the operating conditions of the electric vehicle in which the motor is used. Mobile power measurements offer challenges for both mechanical and electrical systems. One of the primary challenges is that the electrical frequency, which dictates speed, is constantly changing. This creates a need for a cycle detection (frequency tracker) algorithm to correctly measure electrical power. Traditional power analysers were designed for measuring power lines at 50 and 60 Hz and they use a phaselocked loop (PLL) technology that takes time to settle onto a fixed frequency. This settling time is often in the order of seconds. Once the PLL has settled on a waveform, it determines the frequency and will use the time period for RMS and power measurements. If the frequency is constantly changing, the PLL will not settle and it will make its measurements on an arbitrary time period. This often results in impossible results such as efficiencies greater than 100%. owing to the dynamic nature of vehicle speed. However, the latest systems for testing electric machines and drives make mobile electrical power measurements possible in real-world operating environments. Importance of dynamic power Electric vehicle torque and speed are dependent on voltage and current, which are constantly changing in frequency and amplitude. The measurement of these signals requires a method of tracking the frequency to properly measure power. An advanced method of frequency tracking, such as cycle detect, allows for testing beyond the simple static setpoint power and enables users to test dynamic power. Dynamic losses are additional losses introduced during a transient condition. During the first few cycles of the machine, there is an increase in reactive power and subsequent losses. These increased losses during the transient condition would not be understood or captured by traditional efficiency maps, but will contribute to electric vehicle range and performance. By having an accurate measurement and better understanding of these losses, engineers can start to optimise drive cycles and the actual performance of the vehicles. Mobile data acquisition Mobile data acquisition is a cornerstone for vehicle evaluation, and it is used increasingly to evaluate structural durability, noise and vibration characteristics. Engineers are looking to understand the final product and how all the subsystems work together to evaluate the customer experience and ensure that the vehicle will meet durability claims. This requires instruments tailored to the application, from data acquisition systems to power analysers. Data acquisitions can have hundreds of channels of strain, acceleration and temperature sensors as well as CAN Engineers [need] to understand the final product and how all the subsystems work to evaluate the customer experience Integration of in-vehicle power measurements (Image: HBK)
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