A8.2 - Temperature Estimation of Induction Machines Based on Wireless Sensor Networks

Abstract

The 4 th -order Kalman filter (KF) algorithm is implemented in the wireless sensor node to estimate the temperatures of the stator winding, the rotor cage and the stator core in the induction machine. Three separate wireless sensor nodes are used to acquire and preprocess the input signals. The hall sensors are used to acquire the three-phase stator currents and voltages of the induction machine. All of them are processed to Root-Mean-Square (RMS) in ampere and volt. A rotary encoder is mounted for the rotor speed and PT1000 is used for the temperature of the coolant air. The processed signals in the physical unit are transmitted wirelessly to the host wireless sensor node, where the KF is implemented with fixed-point arithmetic in Contiki OS. Compared to the floating-point implementation, the fixed-point implementation has the same estimation accuracy of 97% at only about one-fifth of computation time. Temperatures of the machine could be monitored by an App on a smart phone with internet.