High-frequency modeling of current sensors

Reflected-wave transient voltages that result from fast insulated gate bipo lar transistor voltage-source inverters have received considerable investig ation. Modeling, simulation, and attenuation of these transients require so phisticated motor and cable models, Most drive suppliers now provide combin ations of passive and active solutions to mitigate the adverse effects of o vervoltage stress, however, the costs of the passive solutions often exceed the cost, of the drive. Another aspect of low-risetime devices, not examin ed to the extent of the overvoltage problem, is the resulting current from traveling waves, Current sensor fidelity limits the ability of modern drive s to detect peak current and can result in current feedback distortion. Thi s paper presents recent research into the response, modeling, and construct ion of Hall-effect current sensors, Models for Hall-effect current sensors are introduced and compared. Experimental and simulation results demonstrat e the complexity of the common current sensors employed in modern adjustabl e-speed drives, A comparison of the sensor response and the model's predict ion demonstrates the difficulty associated with accurate current detection, Finally, the paper presents design guidelines to reduce the corrupting inf luence of high-frequency differential and common-mode currents.