This paper describes a method to operate a switched reluctance machine (SRM) sensorless with a precise position estimation but without the necessity of a prior known machine characteristic. When a machine is connected to the inverter for the first time, an initialization sequence is started to determine the inductance profile of the machine automatically. Within this sequence the machine is started and the inductance of all phases is recorded over time while the machine is rotating. From the data the rotor position is extracted and linked to the recorded inductance values. The data is finally merged to one inductance profile, which is used for controlling the machine. Only information about the machine configuration, the maximum allowable machine speed and phase currents must be provided. The proposed method was implemented on a test bench and verified with a 2 kW four-phase SRM using direct average torque control (DATC).
This paper presents an analytical evaluation of sensorless methods for the operation of permanent magnet synchronous machines. The influence of position estimation errors on the stability of a current controller and the deviation of the actual current value from the reference current are considered. Taking these effects into consideration, a flux estimator and a signal injection method are analyzed. Accuracy estimations and design guidelines for the implementation of the two methods are given.Index Terms-flux estimator, sensorless control, signal injection NOMENCLATURE i r d , i r q d-and q-axes currents in rotor frame u r d , u r q d-and q-axes voltages in rotor frame L d , L q d-and q-axes inductances L d ,L q estimated d-and q-axes inductances R s ,R s stator resistance and estimated value ω s r
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