Inverter device nonlinearity characterization technique for use in a motor drive system

This paper introduces a detailed nonlinearity characterization technique for insulated-gate bipolar transistor inverters in a drive system which is able to measure device nonlinearities. Methods are derived from measurements of the voltage on the inverter phases. These measurements are obtained while applying a set of direct currents to an electrical machine. These methods are then applied to tests using alternating current. The study of inverter nonlinearities is useful in order to improve controller accuracy, implement sensorless controllers, and conduct condition monitoring. These methods fulfill the need to characterize each device in an inverter. In addition to characterizing every device using either AC or DC current, the method is resistant to noise; for these reasons the method is applicable in the field. Simulations and experimental work demonstrate the benefits and applicability of the methods.