A LabVIEW based virtual instrument for on-line induction motor parameters identification

An automatic procedure to identify online the induction machine parameters of the steady-state equivalent circuit is presented. The procedure starts with the acquisition of input current and voltage instantaneous values and their processing to obtain the following dataset of variables: current and voltage first harmonic values; their displacement; and the slip value. The slip value is obtained through the current spectrum lines due to the rotor slotting. This first step is automatically iterated if the operating condition changes, in order to obtain more sets of variables. Different methods identify the parameters of the equivalent circuit, starting from the available sets of variables. All this process, configured as a virtual instrument, is implemented in the LabVIEW environment and can be included in a diagnostic system to detect machine health conditions, in order to expand system capabilities.