Development of a High-Bandwidth Current Sensor for High-Frequency Power Applications
by
R114
B242
Abstract:
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 differential 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 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 100 MHz.