Motor Dynamic Response Research Articles

Mitigation of supply current harmonics in fuzzy-logic based 3-phase induction motor

<span lang="EN-US">A parallel active power filter is employed to enrich the quality of power in the power grid with non-linear loads. The induction motor drive requires better performance in many applications. The overall performance enhancement is performed by mitigating the delivery of current harmonics and related warmness losses in an induction motor. In this paper, comprehensive performance evaluation of a 3-phase induction motor is mentioned with fuzzy logic controller-based shunt active filter (SAF), and the outcomes are compared with proportional integral (PI) and proportional derivative controller (PID) controller. In this work, a new scheme of shunt active filters is connected at the supply side of the vertical speed indicator VSI fed induction motor. The simulation was performed by a fuzzy logic controller (FLC) based 3-</span><span lang="EN-US">f</span><span lang="EN-US"> induction motor drive (IMD) using parallel SAF. Simulation result from MATLAB/Simulink software has been presented to understand the reduction in harmonics by introducing an active filter near the supply side. A fuzzy suitable judgment controller is brought on this work to develop the induction motor dynamic response. Analysis of the simulation outcomes, the usage of MATLAB/Simulink software program for the proposed FLC managed induction motor had been demonstrated and overall performance enhancement of induction motor was discussed.</span>

Comparative Study of Five-Level and Seven-Level Inverter Controlled by Space Vector Pulse Width Modulation

<p>This paper presents a MATLAB/SIMULINK model of two multi-level inverter topologies. Algorithms based on space vector modulation (SVM) technique are developed in order to conduct a comparative study on diode clamped five and seven level inverters. The scheme used to develop these control algorithms are based on symmetrical sequence because of the symmetry of the switching wave. Both topologies are simulated and analyzed using a squirrel cage induction motor. The results have showed that the best motor dynamic response with less harmonic distortion and torque fluctuations is obtained when seven-level inverter is employed.</p>

Torque derivative control in induction motor drives supplied by multilevel inverters

The study deals with a novel torque derivative control of induction motor drives. The proposed technique is mainly finalised to improve the motor dynamic response regardless of speed operating conditions, ensuring satisfactory values of both motor currents distortion and torque ripple. The core of the discussed approach is a special look-up table, in which the converter voltage space vectors are sorted with respect to their influence on the torque derivative, taking also into account their influence on the flux magnitude. The table is indeed accessed by a desired torque derivative value, obtained by properly processing the output of hysteresis controllers. Moreover, a variable duty-cycle technique is implemented in order to ensure a satisfactory torque ripple in steady-state conditions. The proposed algorithm, suitable for a general multilevel inverter, is numerically tested on a three-level neutral point clamped inverter and its performance are compared with the ones obtained by a traditional direct torque control method based on three speed ranges look-up tables. The control is then validated experimentally by means of a reduced scale laboratory prototype fixing the same condition used for numerical analysis.

Generalised look‐up table concept for direct torque control in induction drives with multilevel inverters

This study deals with direct torque control (DTC) of induction motor drives when a multilevel inverter is involved. The proposed control technique is finalised to reduce the amplitude of torque oscillations and to improve the motor dynamic response regardless of operating speed conditions while assuring a satisfactory input current distortion. This is achieved by using a special look-up-table built with a novel approach. The control itself is based on the application in each sampling interval of one or two voltage vectors suitably selected, in order to ensure low electromagnetic torque ripple in steady-state operations and fast dynamic behaviour in transient operations. In the algorithm, the converter voltage vectors selection is carried out by using a novel look-up table whose entry points are computed by means of a specialised relation, starting from the outputs of multilevel hysteresis controllers. The suggested method, suitable for a generic multilevel inverter, is detailed for a neutral point clamped three-level inverter. The proposed algorithm is validated by several numerical results, and compared with a DTC algorithm based on a traditional three-speed range look-up tables. Finally, some experimental results, obtained with a scale laboratory setup, are shown, discussed and compared with the numerical ones.

Rotor design to improve dynamic performance of axial flux hysteresis motors

In high-speed axial flux hysteresis motors (AFHMs), the hysteresis ring and the hysteresis ring holder have the main roles of producing hysteresis torque in steady state and eddy current torque at sub-synchronous speed, respectively. In conventional AFHM, and especially in the high-speed AFHM types, the hysteresis ring holder is placed between the hysteresis ring and stator to produce more eddy current torque at the time of starting. Since the minimum magnetic air gap can cause better motor performance, the previous research exchanges the hysteresis ring place and its holder. However, it has worst motor dynamic response as a result. To cope with these issues, a new model is proposed in this study. A thin copper piece is attached at the bottom of the hysteresis ring to improve the eddy current torque and consequently motor dynamic response. Then finite element analysis is done in order to acquire the accurate copper thickness and investigate the new proposed AFHM. Furthermore, experimental setups are provided and AFHM results in all cases are measured. The obtained test and simulation results show that the new proposed model make a better dynamic performance for the AFHM.

Transient Model of Air-Conditioner Compressor Single Phase Induction Motor

This paper describes an air-conditioner (A/C) compressor single phase induction motor (SPIM) model for use in an electro-magnetic transients (EMTs) simulation. The system of differential equations representing the SPIM model is developed and formulated. The angular position of the rotor shaft is retained in the electrical and mechanical equations of the model so that position dependence of the driven-load torque can be explicitly recognized. The equivalent circuit of the proposed model is represented as an interface to the external electric network in the EMTs simulator. Motor dynamic response to voltage dip at different points on the voltage waveform has been studied. The rationale of motor stalling is explored. Multiple aggregate units of the proposed model have been implemented on a distribution feeder to test and verify the motor dynamics in an EMTs simulation.

Non-linear Generalized Predictive Control of Traveling-wave Ultrasonic Motor

Based on the experimental data of an ultrasonic motor's dynamic response, the non-linear Hammerstein model of an ultrasonic motor driving system is obtained by using particle swarm optimization. This model uses motor-driven frequency as input and rotating speed as output. As such, the main characteristics of nonlinearity in the ultrasonic motor operation process can better be expressed with a relatively simple form and a kind of feasible modeling method for model identification of ultrasonic motor system is proposed. Based on this Hammerstein model, the self-tuning nonlinear generalized predictive speed control strategy of an ultrasonic motor is proposed and the tuning method of the controller's parameters is also discussed in detail. This control strategy utilizes the roll forecasting, optimization and online self-tuning methods to deal with the nonlinearity of the ultrasonic motor. The experiments with a variety of disturbances indicate the efficiency and robustness of the proposed strategy.

FLC-Based DTC Scheme to Improve the Dynamic Performance of an IM Drive

This paper presents a fuzzy logic hysteresis comparator-based direct torque control (DTC) scheme of an induction motor (IM) under varying dynamic conditions. The fuzzy logic controller (FLC) is used to adjust the bandwidth of the torque hysteresis controller in order to reduce the torque and flux ripples and, hence, to improve motor dynamic response. The effects of torque hysteresis bandwidth on the amplitude of torque ripples of an IM are also discussed in this paper. Based on the slopes of motor-estimated torque and stator current, an FLC is designed to select the optimum bandwidth of the torque hysteresis controller. This paper also proposes a simpler algorithm than the conventional trigonometric function-based algorithm to evaluate the sector number (required for DTC scheme) of the stator flux-linkage space vector. The proposed algorithm reduces the computational burden on the microprocessor. In order to test the performance of the proposed FLC-based DTC scheme for IM drive, a complete simulation model is developed using MATLAB/Simulink. The proposed FLC-based DTC scheme is also implemented in real time using DSP board DS1104 for a prototype 1/3 hp motor. The performance of the proposed drive is tested in both simulation and experiment.

Effective identification of induction motor parameters based on fewer measurements

This paper applies genetic algorithms (GAs) to the problem of parameter identification for field orientation control (FOC) induction motors. Kron's two-axis dynamic model in per-unit system is given, and the model's parameters are estimated by a GA using the motor's dynamic response to a direct on line start. Results with different levels of measurement noise are presented for the model both in the per-unit system and in actual values. For comparison, the results of a simple random search (SRS) method under the same condition are also given. The results show that the parameter identification accuracy, the convergence speed and the practicality of the algorithm have been improved significantly by use of the model in the per-unit system. The results also show that fewer measurements are required to identify the induction motor parameters accurately.

Effective Identification of FOC Induction Motor Parameters Based on Few Measurements

This paper applies genetic algorithms (GAs) to the problem of parameter identification for field orientation control (FOC) induction motors. Kron's two-axis dynamic model in per-unit system is given, and the model's parameters are estimated by a GA using the motor's dynamic response to a direct on-line start. Results with different levels of measurement noise are presented for the model both in the per-unit system and in actual values. For comparison, the results of a simple random search (SRS) method under the same condition are also given. The parameter identification accuracy, convergence speed, and practicality of the algorithm have been improved significantly by use of the model in the per-unit system. Fewer measurements are required to identify the induction motor parameters accurately.

Parameter Identification for FOC Induction Motors Using Genetic Algorithms with Improved Mathematical Model

This paper applies genetic algorithms (GAs) to the problem of parameter identification for field orientation control (FOC) of induction motors. The motor's general model, which is generally used for speed control applications, is improved for the purpose of improving the parameter identification accuracy by the assumption that the stator self inductance Ls is identical to the rotor self inductance Lr. The motor's dynamic response to a direct on-line start is used to estimate the parameters. Results are presented for both the general and improved mathematical models of the induction motor, using different levels of measurement noise. For comparison, the results of a simple random search (SRS) method under the same condition are also given. The results show that the improved model increases significantly the parameter identification accuracy and that the performance of the GA method is much better than that of a simple random search technique. It is concluded that the GA is a powerful tool for parameter identification.