Offline Measurement of Stator Resistance and Inverter Voltage Drop Using Least Squares

Modern industrial and commercial electrical drives are typically designed to control motors of different types, operating under scalar, field-oriented or direct torque control. These execute various algorithm such as sensorless control, temperature monitoring, etc., which require the knowledge motor drive parameters. In order do this, inverters allow data be input manually self-commissioning routines before running motor. The parameters necessary for proper operation include phase resistance inverter voltage drop, especially important in low-speed range. This paper presents an offline technique estimation mentioned parameters, can obtained with enough precision overwhelming majority applications. proposed consequently injects DC-current several levels into stator a motor, measuring corresponding voltages. Each pair current is point characteristic drive, thus set these points maybe approximated first polynomial using least squares method. desired drop resistance. experimental section analyzes errors their dependence on number injected levels, values filtering capability algorithm. After that, authors give suggestions selection, depending demanded precision. Finally, demonstrate mass-producing dishwasher adopted this technique.