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This paper deals with the effect of laminations on natural frequencies of asynchronous machine magnetic core. Measurement of natural frequency of stator core is presented. Numerical model and calculation of natural frequency of core is described in next part. Comparison of measurement and mathematical model is discussed.
Partial discharges (PD) are widely known to occur in medium- and high-voltage applications. Recently, it has been observed that owing to the use of modern variable frequency converters, an environment that contributes to partial discharges is also found in low-voltage motors. Low-voltage machines are vulnerable to partial discharges because their winding insulation is not designed to withstand the...
An algorithm for Continuous Set Nonlinear Model Predictive Control (CS-NMPC) is investigated. The proposed strategy is employed to realize flux and torque control for an Induction Motor (IM). It is implemented on an FPGA-based system and its effectiveness is demonstrated with experimental results. The iteration based structure of the algorithm, makes it possible to reduce the needed logic resources...
The paper introduces a unified model, expressed in state space variables, suitable to be applied to a plurality of conventional AC machines: IM, R-SM, SPM-SM, PMAR-SM, IPM-SM, WR-SM. Even if coefficients in the parameter matrixes differ among machine types, with this model, only one implementation scheme (integration of state space equation) is used for all the machine type. Extension to sensorless...
In variable speed drive applications the inverter fed induction machine is one of the most reliable systems. However, increasing demands on efficiency leads to higher wear of all system components. Unexpected machine breakdowns cause economic losses and/or undesired scenarios in safety-critical areas. Thus condition monitoring of all components can reduce the risk of outages due to faults. High electrical...
This work proposes a model for induction machines in natural coordinates “abc”, developed considering the nonlinear characteristics of saturation. Traditionally, the models for the induction machine including this effect make use of linear transformations. However, the nonlinearity of saturation does not allow the use of these transformations, giving invalid results. Flux linkage in each phase leads...
We present in this paper a control of an induction generator wind turbine connected to the grid. We applied a modulated hysteresis direct torque control (MHDTC) to the induction generator (IG). This control strategy consists in superposing to the torque reference a triangular signal, as in the PWM strategy, with the desired switching frequency. We obtain a new modulated reference which is compared...
An Expert System (ES) for the analysis and design optimization of low-power, three-phase induction motors (IMs) is presented. The ES is based on analytical models, which are carefully selected from literature, and coupled together to calculate motor performance characteristics. These performance characteristics are computed within a few seconds. Also, validation of the ES calculation results against...
This paper presents a simple rectifier configuration for SCIG (squirrel cage induction generator) applied to variable speed wind turbines. The proposed rectifier consists of a diode rectifier and a series reactive power compensator named MERS. Advantages of this configuration are reduced active semi-conductor device rating needed and line frequency switching operation of the series compensator. Experimental...
In this paper, the performance improvement of an induction motor of which stator core is made of molded SMC (Soft Magnetic Composite) is presented. By using SMC, 3D shaped core is easily constructed. The teeth of the stator core extended in order to enlarge the pole surface area in the same outer dimension of the motor. In this presentation, the motor performance of the motor using the core made by...
An encoderless model predictive torque control (PTC) is proposed in this paper. By using the MRAS estimation method to PTC, the system becomes simpler and has the virtue of low cost due to the absence of PWM modulator and speed measurement components. In implementation, a compensated MRAS is considered because of the stator current measurement errors. The experimental results confirm that this control...
A new fault detection method for induction machines (IM) is analyzed with respect to transient magnetic material behavior by means of finite element (FE) modeling. The detection method uses the machines inverter to excite the IM with transient voltage pulses and measures the corresponding phase current responses. To account for the material behavior transient BH curves are identified from measurements...
In this work the design and control of a four-phase induction machine (4P-IM) is addressed. The 4P-IM is controlled using a four-phase voltage source inverter (4P-VSI) with a generalization of the classic direct torque control (DTC) scheme. An analysis of the available valid switching states and voltage space vectors is developed and a switching table is obtained. Finally, the system's fault tolerant...
The development of a control strategy suitable for Permanent Magnet (PM) and Induction Motor (IM) drives is considered. The proposed scheme is based on the Direct Flux Vector Control (DFVC) method, adapted for positioning systems (over azimuth and elevation). A comparative study of IM and Interior PM motors performances is presented.
Linear Induction Motors (LIMs) are used to control the propulsion of maglev transportation and carrier system. In the usual maglev transportation system using LIM, the levitation of the carrier are controlled by the levitation magnets. It has problem that the controls of the LIM and of the levitation magnets interfere each other because the attractive force generated by the LIM affects the levitation...
Pump, compressor and fan systems often have a notable energy savings potential, which can be identified by monitoring their operation for instance by a frequency converter and model-based estimation methods. In such cases, sensorless determination of the system operating state relies on the accurate estimation of the motor rotational speed and shaft torque, which is commonly available in vector- and...
The efficiency of a motor drive combined with an inverter increases by exploiting the maximum voltage level that can be provided by the inverter. This paper presents a novel control strategy for the induction motor in the field-weakening range. The inverter's voltage margin is utilised using only the variation of the argument of the stator voltage vector and avoiding any zero voltage vectors in steady...
In this paper we present a guide to choose an energy efficient configuration of a pump drive system in an early stage of design process based on an user-defined load profile. All subsystem models are briefly presented, including different control methods (speed and throttle control) and single or cascaded pump drives. These models are based on free accessible parameters of data sheets. The analysis...
The modern design of an induction traction machine includes a complex of coupled electromagnetic and thermal analyses for effective utilization of machine's space. This paper summarizes a comparison between less and more complicated ways of induction machine's modelling.
The paper deals with the design of irregular AC windings by a new method. The new method is based on the notion of “local density of conductors”. Design of the interspersed winding 1–3–1 is shown as an example of using this new method. This type of winding can be used to reduce higher harmonic components of magnetic flux density in the air gap, mainly the fifth and the seventh harmonic. This new method...
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