Applications & Cases
Reference design for inverters March 2016
First integrated solution for e-mobility and industry
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EPCOS AG A TDK Group Company Edition 2018 www.epcos.com 1 / 11Applications & Cases
t
egrated solution for inverters to be used in e-mobility powertrains and industrial applications. The design
enables developers to test and implement drive concepts quickly and easily.
Asynchronous motors are used in the majority of electrical drives for industrial applications, while automotive drives
employ synchronous motors with permanent magnets. For both automotive and industrial applications, the
manufacturers limit these motors to a maximum permissible voltage rise (dv/dt) at the inverter terminals of about 5
kV/s (according to IEC 60034-18-41). The reason for this limit is the dielectric strength of the windings. When these
motors are driven by an inverter high earth leakage currents occur that are caused by parasitic capacitance in the
windings in combination with the dv/dt of the inverter. These currents can lead to sparking in the bearings, cause
surface erosion and therefore severely limit the service life of the bearings.
In order to achieve high energy efficiency, the power semiconductors of the inverters are operated at switching
frequencies in the range between 4 kHz and 15 kHz. Due to the necessary slew rate and switching frequencies, this
results in harmonics with a high amplitude in the frequency range around 1 MHz. In automotive applications, in
particular, the power drive causes significant interference in the MW band (526.5 kHz to 1606.5 kHz), making MW
reception nearly impossible in a car, for example.
New development delivers significant improvements
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