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At standstill and low-speed, signal-injection methods are required to estimate the rotor position of a permanent magnet synchronous machine (PMSM). Therefore, usually either the resistance- or inductance-based saliency is examined. Although the latter case can be found most in literature, it is possible that the sensorless performance can be improved by exploiting the position information of both...
The purpose of this paper is to investigate high-speed machine design enabled through the use of silicon-carbide based power electronic inverters. Silicon carbide based switching devices have superior properties compared to silicon based devices, and they are able to change the paradigm for high-speed machine design. High-speed machines with a higher number of poles are shown to reduce the machine...
Modern day manufacturing practices are focusing on maximizing production while actively pursuing ways to mitigate potential failures in their products. With rotating machinery, part of this pursuit requires qualification checkpoints during manufacturing processes. For motor stators, it is essential to perform in-process insulation testing to ensure the dielectric integrity of the system is maintained...
The transversalflux machine DYNAX is a high torque and power density machine. Unlike conventional rotary field machines the transversalflux machine consists of three single phase stators with coupling by a common rotor for constant torque generation. Therefore models of conventional machines cannot be used to describe the entire behavior of the DYNAX, even if the fundamental voltage and current waves...
Inter-turn short circuit fault (ISCF) detection, in permanent magnet synchronous machines (PMSM) was developed using a physics-based back electromotive force (EMF) estimator. The electro-thermal saturation-dependent model of the machine was employed in the heart of the open loop estimator. The fault detection system works based on the difference between the estimated EMF and a reference EMF. A 0.8...
This paper presents the dynamic behaviour of a large doubly-fed motor-generator during and after the fault. Such machines will be included in pumping-storage plants in Slovenia and they will become an important part of Slovenian electric-power system, so it is important to know the behaviour of these machines. During the fault—;where doubly-fed motor-generator operates as an asynchronous machine—the...
This paper investigates the influence of inverter nonlinearity on the parameter estimation in permanent magnet synchronous machines (PMSM). An estimator based on model reference adaptive system (MRAS) is firstly described for simultaneously estimating the stator winding resistance and rotor flux linkage, together with injection of a pulse of id <; 0 which is required for activating the estimation...
Until recently, power plant operators have had very limited options for on-line monitoring of the health of motor and generator rotors, particularly those with brushless excitation systems. Degradation of field winding insulation can lead to ground faults or shorted turns, with little or no warning. Moreover, the capability to monitor local hot spot temperatures on rotor windings in service has not...
Semiconducting fiberglass tapes were developed in order to achieve a stable, heat-resistant, chemically homogeneous semiconducting material with electrical resistance, which would be independent of the probability of the distribution of semiconducting fillers (such as carbon-black or SiC) in the dielectric binders, and in order to avoid the influence on the material resistance of the binder thickening...
Usually skin effect is neglected in the design of medium speed machines when using random wound windings. That is because it is thought that parallel strands mix enough so that the skin effect can be neglected. In medium speed machines operating in the frequency range of 100 - 300 Hz the skin effect problem may come up in cases where the slots have only one or a couple of turns despite the fact that...
A direct online stator winding resistance measurement scheme is proposed as a means to improve standard efficiency tests of polyphase induction machines. To enable resistance measurement a DC current is injected online into the stator winding and response voltages are captured. In experimental tests an unequal number of anti-parallel diodes has been used to inject DC current. A bespoke temperature...
The paper deals with methods and algorithms for the estimation of the induction motor equivalent circuit parameters starting from the geometrical and electrical data generally available after an electromagnetic design. The main aim of the paper is to help the readers to pass from the theoretical analysis to numerical code suitable to be included in own design software. For this reason, the step-by-step...
A non-intrusive stator winding resistance estimation technique is proposed for soft-starter-connected induction motors. By changing the gate drive signal of the thyristors in the soft-starter, a small dc bias can be intermittently injected to the motor. Based on continuous monitoring of the stator winding resistance, a new thermal monitoring scheme is proposed using only voltage, current, some motor...
In this paper a simple dynamic model for induction machines (IM) with inter-turn winding fault is established. Finite element method is used for parameter identification of the machine under fault condition. The proposed dynamic model is validated by time stepping finite element (FE) analysis. The dynamic model results exhibit the same trend as predicted by FE analysis for different fault insulation...
The transient behaviour of synchronous machines is largely determined by the configuration of their damper windings. In this paper, the influence of damper end connections on the induced voltage in the open phase of a machine during a two-phase sudden short circuit is investigated using a commercial Finite Element package. It can be shown that a substantial increase of the resistance between the damper...
Axial-flux, Permanent-magnet machines are used in different applications where the power and torque density requirements are very high. These machines have simple structures, relatively high efficiencies and low cost. The parameters of these machines are very small compared with the parameters of conventional machines. Different measuring methods are normally used in order to obtain good estimates...
In this paper, a mechanical speed estimator based on the model reference adaptive-system (MRAS) principle is evaluated for a single-phase induction motor operated as two-phase motor. In three-phase drives with complete vector control/MRAS system the effect of the rotor time constant is auto-compensated by the decoupling compensators or slip calculation. However, it is not feasible in pure MRAS scheme...
In this paper, a method of sensor less best exciting in towards polarity by stator-electricity of synchronous motor is presented on the base of calculated best exciting time through simulation in order to solve the present problems and enhance the reliability of excitation exist in asynchronous starting of synchronous electrical machine. Detect and analyze the wave of stator current to catch the best...
The eddy loss of stator windings in synchronous generator was calculated using analysis method and finite-element method, the distributed characteristic of stator windings temperature field was studied. In this paper, the distribution characteristic of eddy current of windings in rectangular slot was analyzed first by using analytical method, and the mathematical representations of eddy current were...
This paper discusses the three most common in-process electrical winding tests. These include the hipot, high voltage impulse and winding resistance tests. Then it discusses additional auxiliary tests which are commonly performed on windings such as inductance, rotation direction, magnet field mapping and partial discharge. Important parameters for properly conducting each of the tests in a production...
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