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LTT24: The future of battery-driven electric motors


Electric drives are conquering our daily lives: cordless screwdrivers, angle grinders, electric bikes and electric cars must function with maximum efficiency over the greatest possible load ranges.

Test standards, such as the DIN IEC 60034-2-3, define the test requirements for determining the efficiency of such inverter-fed drives. The LTT24 is the only device worldwide offering the necessary bandwidth and accuracy.

The underlying chopped square wave voltage and the associated current must lead to correct phases and amplitudes and a performance statement with a maximum error tolerance of 0.3%. In order to achieve this accuracy of 0.3%, the theoretical frequency consideration of a square wave voltage means that all frequencies up to the 19th harmonic of the switching frequency of the inverter must be taken into consideration. At a switching frequency of 10-20 kHz, this is a signal bandwidth of 0-380 kHz in which the signal fidelity of all components must be better than 0.3%. This requires a measurement technology with a continuous sampling rate of 2-4 MHz without distorting filters. Particularly in high-performance automotive electric motors, increasingly high battery voltages, currently up to 800 V, are used.  At a bandwidth of 380 kHz, a pulsed 800 V signal shape becomes a real challenge. The challenge is to build the high-voltage divider in such a way that its total measurement error is guaranteed to remain below 0.3% over the entire frequency, voltage and temperature ranges despite the fact the non-linearities of all electronic components already have a massive impact here.

At the same time, the pulsating current of this 800 V pulsating inverter voltage must be measured. That is a real challenge for the galvanic isolation of the current input. The LTT24 is the only device worldwide that successfully combines the required bandwidth and accuracy. No other power meter can meet the signal accuracy required by the standards in terms of voltage AND frequency. Other devices fail to achieve either the required accuracy or the required bandwidth.

The LTT24 is the only solution you can rely on to support your test bench design. The sky is the limit!

Get information material on the standard-compliant LTT24 power analyzer today: kontakt(at)tasler.de.

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