Influence of inverter-nonlinearity and measurement setup on zero speed sensorless control of AC machines based on voltage pulse injection

In this paper the influence of the non-ideal behavior of power electronics, sensors, and signal processing on speed sensorless control is addressed and investigated. The speed sensorless control signals are obtained from the transient current response resulting from an excitation of the machine with voltage pulses. The investigations are focused on sensorless control of induction machines, however the results are applicable also for other types of AC machines. Reference to the inverter the influence of interlock dead-time as well as the voltage drop of the power electronics is assessed. Simulation results are given to support the separation of the different effects. Additionally measurement results are presented to show the influence on the resulting control signals. Different ways to consider and compensate the different deteriorating effects with respect to sensorless control are discussed and compared.