Development of a High-Bandwidth Current Sensor for High-Frequency Power Applications

The aim of this master thesis is to develop a high-bandwidth current sensor for a nominal
design current of 100 A and a nominal design bandwidth of 100 MHz.
After an analysis which properties are important to develop a current sensor, a requirement
list was stated. Several current sensing methods were described and their qualification for
the stated requirements were evaluated. With the resulting sensing concept, consisting out
of Rogowski coils and magneto resistors, a system design was elaborated. One requirement
was to develop a current sensor which needs less effort in series production than a regular
Rogowski coil. Therefore, a planar Rogowski coil was proposed for this sensor development.
Furthermore, a magnetic field simulation was designed. Based on the results, a optimal
placement simulation for both sensors was carried out. In the final design phase, the
galvanic insulation requirements of 4.8 kV based on the corresponding standards were
investigated and implemented. The test equipment used in this thesis was designed
and build in-house at IPE (KIT-ADL). Commercial solutions did not offer the suggested
requirements for generating a double pulse with the necessary rise time to characterize the
... mehr
current sensor’s bandwidth. The test equipment was able to apply pulses with a maximum
current of 200 A and a rise time of 1 ns to the device under test. The prototype is able to
sense a current up to ±100 A with a bandwidth of 20 MHz.