Upcoming seminars at IEA
Thursday 18/10, 15:15, M:IEA (IEA seminar room), MSc Degree Project Presentation
" Differential Measurement Probe with High Common Mode Rejection "
Measuring signals with high frequency common mode components are typically prone to measurement
errors due to low common mode rejection at high frequencies. The purpose of this master thesis is to
design a measurement probe that presents sufficient common mode rejection to measure motor drive
current directly at the switching stage, before filtering.
Outlined in this work is the design process, on a block diagram and simulation level, culminating in the
construction of a prototype. The measurement probe consists of sensor head and a receiver that are
fiber optically isolated from each other. It has a signal chain that splits the signal into a high and low
frequency path. The high frequency path is frequency modulated and the low frequency path is digital.
In the receiver, these two paths are joined before being output as an analog signal.
A signal chain has been simulated that shows a DC-100 MHz response with an amplitude accuracy of
2.9%, dynamic range of 53 dB, dropping to 38 dB at the end of the passband and, a spurious free
dynamic range greater than 40 dB. Furthermore, a prototype has been constructed but has not been
debugged to a degree that permits meaningful measurement results.
Supervisors: Lars Lindgren, Johan Wernehag
Examiner: Mats Alaküla
Seminars are held in the IEA lecture room, ground floor in southeastern corner of the M-building, unless stated otherwise.
Seminar Announcer:Max Collins.