Experimental Identification of the Magnetic Model of Synchronous Machines

Abstract

This paper proposes and formalizes a comprehensive experimental approach for the identification of the magnetic model of synchronous electrical machines of all kinds. The identification procedure is based on controlling the current of the machine under test while this is driven at constant speed by another regenerative electric drive. Compensation of stator resistance and inverter voltage drops, iron loss, and operating temperature issues are all taken into account. A road map for implementation is given, on different types of hardware setups. Experimental results are presented, referring to two test motors of small size, and references of larger motors identified with the same technique are given from the literature.

Identification of Three-Phase IPM Machine Parameters Using Torque Tests

“…The tests are performed at different current levels to take into account magnetic saturation effects. The method is not influenced by stator resistance variations due to temperature as happens in other schemes, such as [15]. The complication of dealing with inverter non-linearity effects is also ruled out even if the tests are carried through the inverter, as will be shown in the results.…”

“…3 [15]. The machine has substantial saliency as the d-and q-axis inductances are in the ratio of 1:10.…”

“…Furthermore, the stator resistance increase due to temperature is also excluded from affecting the results as the parameter values depend only on the measured torque that is inherently independent of stator resistance. However, the need of having a precise torque sensor for the tests can be an additional requirement of the proposed method as it is not required by other methods, such as [15]. Fig.…”

“…It must be noted that if the machine parameters are not known, the voltage signal application in open-loop may trigger overcurrent protection. A different approach is proposed in [15] that again needs an entire drive system along with a prime mover that turns the shaft at constant speed. The machine under test is supplied with different current vectors, using high bandwidth current controllers, in the rotor dq synchronous frame, and the fluxcurrent relationship for the d-and q-axis, collectively known as the magnetic model, are identified.…”

Sensorless commissioning of synchronous reluctance machines augmented with high frequency voltage injection

“…The constant speed test in [3] can be considered the state of the art in terms of accurate identification of the SyRM flux maps.…”