100 MS/s 10-25 MHz Wireless Voltage Probe

For developing and testing of power electronic converters and circuits, voltages and currents have to be measured to verify the proper mode of operation. In cascaded converters or multi-level topologies, the voltages to be measured contain common mode components up to several kV with transients up to several tens of kV/μs. Conventional isolated voltage measurement systems do either not meet the high voltage isolation requirements or exhibit a rather large coupling capacitance to ground. In combination with the high voltage transients, this coupling capacitance on the one hand impacts the circuit under test and on the other hand influences the voltage measurement. To reduce these effects, the coupling capacitance of the measurement system must be minimized. In this paper, a wireless voltage probe (WVP) is introduced to measure accurately on a high and transient reference voltage with minimal impact on the circuit under test. The basic concept and practical realization of the WVP are discussed and finally verified with measurements on a high power medium voltage IGBT converter system.