The Application of Thin Film Sensing Technology in Passive Optical DC Current Sensor

摘要

There are many technical difficulties in existingpassive optical DC current sensor, so a DC current sensorbased on optical fiber thermometry is proposed in this paper.The tested current generates applied voltage by a shunt andtransfers into the change of temperature rising after a thinfilm resistor in the high voltage side. Then the currentinformation is got indirectly by measuring the temperaturesignal. The new project combines the thin film sensingtechnology and the temperature measurement technology. Itdoes not have polarized light, fragile optical glass block andthe power supply in high voltage side, so it does not exist thedifficulties of the main project at- present. As the thin filmresistor is a key device, dynamic characteristic of which isanalyzed. Mathematic model and three-dimensional ANSYSsimulative model of thin film resistance is built. Thermalanalysis is performed according to their shape, material,structure, process and size. An experimental thin film resistoris constructed for testing. Theoretical analysis andexperimental results show that this scheme is available ifappropriate technique are used.