Measurement and Testing of Electric Motors and Inverters
The eDrive testing solution from HBM:
A tool that increases the efficiency of the electric drive of the future
The future belongs to electric drive trains and thus also to electrically driven vehicles - however, the range of electric cars is still limited. Increasing the efficiency of the electric drive train including inverter and electric motor plays a key role.
A problem so far: The standard methods used for performance testing and efficiency measurement of electric drives give only inadequate results. Using HBM's innovative eDrive testing solution makes the difference: Our 'power duo' including the T12 torque sensor and the Genesis HighSpeed data acquisition system allows synchronous, dynamic measurement of mechanical and electrical signals.
Continuous storage of raw data allows live analyses for determining active and reactive power as well as energy conversion efficiency. It is also possible to carry out further, more detailed analyses of fundamental and switching frequency, air-gap moment, slip, iron loss, control behavior etc.
Continuous raw data for verification and analysis
A solid data base is the basis for any profound improvement of electric drives, motors or, of course, generators too. Efficiency can be determined using a power meter, however, it cannot be explained. Nor can approaches towards increasing efficiency be derived from the data.
This is where HBM's eDrive solution comes in: All relevant data as well as currents, voltages, torque, rotational speed and even the motor temperature are continuously stored at high resolution in an integrated system. Another benefit: With a power meter, RMS values are displayed in real time.
The system's actual benefit becomes apparent during further analyses. Using powerful mathematical functions and a formula database, analyses that so far required separate maths packages can now be made directly in the measurement system. Taking measurements using an integrated system users benefit from enormous time savings, flexibility and a lower error ratio.
Motor test and analyses
The formula database enables electric motor or generator data to be directly and quickly evaluated. Two simple measurements - no-load and short-circuit - in combination with existing formulas make determining the equivalent circuit diagram extremely easy. Entering the corresponding formulas, even parameters such as air-gap moment, slip, cogging torque, starting or armature currents and many other characteristic quantities can be calculated.
HBM Webinar: Efficiency Testing on Electrical Drive Trains
Continuous and synchronous acquisition of electrical and mechanical power. Beyond the numbers a traditional power meter computes, the GEN DAQ based eDrive test solution from HBM also delivers raw data. The HBM solution allows in-detailed analysis and result verification in demanding motor / inverter test setups.
The original webinar was held on November 28th 2012.
Efficiency testing: Standard approaches deliver poor results
Currently, power analyzers are normally used on the motor input and torque transducers on the motor output to measure the efficiency of electric motors. The difference between the respective electrical power and the resulting mechanical power generated by the electric motor is the energy loss.
However, statements about the causes of this loss cannot be made in this manner. In addition, the measurement devices, which frequently originate from different manufacturers, need to be laboriously synchronized before a test. This frequently leads to measurement errors. Highly-dynamic power measurements with more than 50 measurements per second are also technically difficult. Another problem with current power analyzers is that they simply deliver final results. But it is precisely the raw data that can provide important knowledge during basic research to understand the process and to develop more efficiency.
The HBM solution: Precise evaluation of efficiency tests on electric drive trains
HBM now promises a remedy: With a combination of Genesis HighSpeed measurement data acquisition and the torque transducer T12. This perfectly matched duo makes it possible to carry out long-term tests with precisely defined characteristics and without annoying synchronization. Continuous measurements of up to an hour in duration, with up to one million measurements per second per channel are therefore child's play.
HBM test and measurement equipment in a test bench for combustion engines and electric motors at Darmstadt Technical University, Institute for Combustion Engines and Vehicle Drive Systems (Institut für Verbrennungskraftmaschinen und Fahrzeugantriebe)
The resulting raw data is then available to developers for precise evaluation. Valuable knowledge can be obtained on this basis for optimizing the efficiency of electrical drives. And HBM also meets the wishes of users for calculation results such as the power factor in the new system with correspondingly new developments.
Case Studies on eDrive Testing with HBM
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Dynosens needed an interface to connect the T40B torque transducer to an EtherCAT fieldbus. The solution: TIM-EC from HBM.
Tests on electric motors present a new challenge when it comes to measurement. French testing company GreenMot has opted for HBM's innovative eDrive testing solution.
White Papers on eDrive Testing with HBM
Calculating space vector quantities and the air-gap moment of asynchronous motors using Genesis HighSpeed and Perception software
Read this article to learn more about the calculation of space vectors and air-gap moments.
The development of electric drives requires power measurements. This article describes the function of the pulse width modulated inverter as well as the calculation of power values with the Perception software.
The emphasis of this article is on the use of mathematical formulas in Perception analysis software for power measurements with the GEN2i data acquisition system from HBM.
We reveal to you the seven major misconceptions about eDrive testing - and how you can enhance your testing of electric motors and make it more reliable.