Slip-ring Induction Motor Research Articles

Dual Side Field Oriented Control of Slip Ring Induction Motor

Dual Side Field Oriented Control of Slip Ring Induction Motor

Slip-Ring Induction Motor Torque and Current Ripple Minimization Using Bang-Bang Current Control

Slip-Ring Induction Motor Torque and Current Ripple Minimization Using Bang-Bang Current Control

Performance Comparison of Electric Drives for Chopping/Shredding Sugarcane in Sugar Industry

A performance comparison of the conventional slip ring induction motor (SRIM) drive and the recently inducted variable frequency drive (VFD) in the sugar industry, for sugarcane preparation (chopping/ shredding of sugarcane), is carried out to assess their effectiveness and to explore better electric drives for the application. These high inertial machines demand high starting torque and mitigating means to reduce surge load due to the impact load imposed on them. Though, both the drives meet the requirement but the SRIM drives are subjected to huge slip power loss, low power factor, unequal load sharing problem for coupled motors and high drop in rpm, whereas VFDs are subjected to the problems of input current harmonics, high dV/dt stress and common-mode voltage (CMV). In this paper, along with the performance comparison a three/four-level multilevel inverter (MLI) fed open-end winding induction motor (OEWIM) drive is also proposed as an improvement over the existing ones.

Analisis Penstabilan Tegangan Output Generator Induksi 3 Fasa

One of the alternative generators in supplying electrical energy is a 3-phase generator made from a 3-phase slip ring induction motor, after which the rotor winding is supplied with a DC source and rotated using a prime mover. The problem arises because of the large % voltage regulation of a 3-phase generator when it is under load. This is because the induction generator has a relatively larger voltage loss when loaded with a certain load compared to a 3-phase synchronous generator. To overcome these conditions, there are several ways that can be used to stabilize the voltage from the generator, namely: setting the excitation current from the generator, setting the connection on the rotor windings (using 2 windings or using 3 rotor windings) and a combination of the two steps above. . Based on the results of experiments that have been carried out, it is known that the method of stabilizing the output voltage by setting the rotor winding connection is less effective than setting the excitation current because it turns out that the results of changing the output voltage are not too significant compared to changing the generator excitation current. In addition, it is also known that the stabilization of the output voltage from an inductive load will require a DC voltage that is greater than when under a resistive load because of the large difference in losses.

Performance Improvement of Induction Motor Controlled by Thyristor Chopper on the Rotor Side

In this paper, the performance characteristics of a variable-speed drive system with a wound rotor induction motor incorporating a 3-phase diode bridge rectifier - thyristor chopper with a modified commutation circuit system on the rotor side were studied. A DC equivalent circuit was used in the analysis of the motor-rectifier-chopper system and suitable equations have been derived for the determination of the system performance. The analytical results obtained are compared with those obtained experimentally to ascertain the validity of the system in practical applications. The results obtained indicate that a true variable speed drive system based on a thyristor chopper-controlled induction motor is successfully implemented. It is shown that the thyristor chopper control using the Hitachi commutation circuit permits the realization of a slip-ring induction motor as a variable speed and improved power factor. Also, the torque level obtained by the chopper control was found to be three times that obtained from conventional rotor resistance control at the same conditions.

Behaviour of Rotating Field in Slip-Ring Induction Motors with Chopper Control.(Dept.E)

Stator currents of slip-ring induction motor having chopper control in the rotor circuit, are no more sinusoidal. The analysis of the air-gap resultant field , due to such currents , results in a different expression for the established rotating field. The derived expression is examined in order to study the rotating field behavior under chopper control. In addition to some of the well known behaviours , a new one had been distinguished and proved by constructing the geometrical pattern of the air-gap resultant field. An effective winding factor is introduced to give the effect of nonsinusoidal stator currents on the magnitude of the resultant m.m.f. harmonics.

Analysis of Slip Ring Induction Motor Drive Using Slip Power Recovery Scheme with Inverter and Chopper Control for Id Fan in Power Plant

Abstract: Induction motors are used as industrial drive and for various applications in power plant due to their rugged, robust and simple construction as well as low cost. The speed control of SRIM is dexterous by slip power recovery scheme consisting of inverter control, chopper control, and rotor resistance control techniques. This paper presents the boost in the performance characteristics and energy saving of SRIM drive by inverter and buck-boost chopper based slip power recovery scheme (SPRS). The simulation model of a WRIM drive using inverter and based buck-boost chopper control has been executed in the Simulink platform. The simulation results using inverter and chopper control have been studied. The active power and reactive power have been taken as parameter for analyzing the energy saving by the drive. The simulation result has shown that inverter chopper control SPRS large amount of energy saving.

An Industrial Survey on Electric Drives and Scope of Multilevel Inverter Based Induction Motor Drives in Sugar Industry

A typical sugar industry has electric motors ranging from a few kW to a few MW. For controlled speed–torque characteristics, at most of the places, variable frequency drives (VFDs) are used. DC drives are also used in place of VFDs at milling and batch type centrifugal machines. Slip ring induction motor (SRIM) drives are invariably used at sugarcane preparation station and also at some large pump and fan loads of the industry. At many places, the type and configuration of electric drives need to be reviewed keeping in view the recent developments in the area and improvements in similar applications in other industries. There is also a need to review the aspect of efficiency and harmonics associated with these conventional electric drives in the industry. Further, the VFDs, wherever installed in the sugar industry, are, invariably, 2-level inverter-based induction motor drives. The potential of the multilevel inverter (MLI)-based induction motor drives, being improved one, also needs to be explored in the industry. This paper presents a survey on types of electric drives presently being used for various applications in the sugar industry, their merits and demerits, further possible improvements in them for power saving and reduction in harmonics along with the potential of application of MLI-based induction motor drives, wherever feasible, in the industry.

Vectorized Mathematical Model of a Slip-Ring Induction Motor

The paper deals with the modeling of a slip-ring induction motor. Induction motors are very often used in industry and their suitable model is needed to reduce control and operating costs. The identification process of self and mutual inductances of the stator and rotor, and mutual inductances between them in the function of the rotor rotation angle is presented. The dependence of each inductance on the rotor rotation angle is determined experimentally. The inductance matrix is then formulated. Taking the magnetic energy of the inductances and kinetic energy of the rotor into account, the Lagrange function is defined. Next, the motor motion equations are obtained. After making some algebraic transformations and using the dimensionless variables, the motion equations of electric circuits and of the mechanical equation are written separately in the forms facilitating their solution. The solution was obtained using the Simulink model for the stator and rotor currents in the form of vectors. The simulation was controlled by MATLAB script. The results of the simulation are presented in the form of basic variables time courses and compared with some values calculated with the use Steinmetz model of induction motor. The work is followed by two appendices, which contain procedures for determining the inverted inductance matrix.

Failure Prediction of Induction Motors: A Case Study using CSLGH900/6-214, 5.8 MW, 11 kV/3ph/50 Hz Sag Mill Motor at Goldfields, Damang Mine

This paper proposes a generalised feed-forward artificial neural network model that fulfils the failure prediction of a three phase 5.8MW, 11 kV Slip-Ring SAG Mill Induction Motor at Goldfields Ghana Limited, Damang Mine. It provides a general understanding of three phase induction motors,faults associated with induction motors and also emphasizes the use of intelligent systems, particularly artificial neural network, a modern failure prediction technology of induction motors. Site analysis and motor data (Current, Power and Winding Temperatures) collection were conducted at the Damang Mine. Simulation results are presented using MATLAB software (2017a) package to develop the fault prediction model. The proposed feed-forward neural network used the Levenberg-Marquardt and Bayesian Regularisation in training.

Microprocessor Based Firing Circuit for Static Slip Energy Recovery Controlled Slip Ring Induction Motor Drive

Microprocessor based firing control scheme of static slip energy recovery (SER) controlled slip ring induction motor drive is described. In the scheme the microprocessor generates firing pulses and also decides the pair of thyristors of the controlled converter to be gated. It uses less number of hardware components. The oscillograms at different points of the firing circuit and at the output of the controlled converter are presented. These oscillograms resemble with the theoretical wave forms.

Issues of Exploitation of Induction Motors in the Course of Underground Mining Operations

Abstract Mining industry is one of the most important customers of electric motors. The most commonly used in the contemporary mining industry is alternating current machines used for processing electrical energy into mechanical energy. The operating problems and the influence of qualitative interference acting on the inputs of individual regulators to field-oriented system in the course of underground mining operations has been presented in the publication. The object of controlling the speed is a slip-ring induction motor. Settings of regulators were calculated using an evolutionary algorithm. Examination of system dynamics was performed by a computer with the use of the MATLAB / Simulink software. According to analyzes, large distortion of input signals of regulators adversely affects the rotational speed that pursued by the control system, which may cause a large vibration of the whole system and, consequently, its much faster destruction. Designed system is characterized by a significantly better resistance to interference. The system is stable with the properly selected settings of regulators, which is particularly important during the operation of machinery used in underground mining.

Design and Analysis of Drive System with Slip Ring Induction Motor for Electric Traction in India

The use of Squirrel Cage for Traction has revolutionised the motive power of a Locomotive. The Asynchronous Motor is rugged with high starting Torque, has a very smooth Voltage and Speed control as compared to a DC Series Motor. When looking at the Traction perspective, a Slip Ring Induction Motor can be an alternative to the Squirrel Cage Motor as it has higher starting Torque and better efficiency than a Squirrel Cage Motor. the Slip Power Recovery scheme also plays a proactive role as ther can be substantial savings of energy in case of a Slip Ring Induction Motor. A detailed design and analysis of a Drive System with Slip Ring Induction Motor for Electric Traction is presented in this Research Paper

Influence of magnetic saturation effects on the fault detection of induction motors

Abstract In this paper, the influence of impact damage to the induction motors on the zero-sequence voltage and its spectrum is presented. The signals detecting the damages result from a detailed analysis of the formula describing this voltage component which is induced in the stator windings due to core magnetic saturation and the discrete displacement of windings. Its course is affected by the operation of both the stator and the rotor. Other fault detection methods, are known and widely applied by analysing the spectrum of stator currents. The presented method may be a complement to other methods because of the ease of measurements of the zero voltage for star connected motors. Additionally, for converter fed motors the zero sequence voltage eliminates higher time harmonics displaced by 120 degrees. The results of the method application are presented through measurements and explained by the use of a mathematical model of the slip-ring induction motor

Rotor side Control of High Power Slip Ring Induction Motor using a Single Thyristor

The aim is to create a Simple control mechanism for speed variations of a HIGH POWER SRIM - Slip Ring Induction motor as an extension to the available Non slip power recovery mechanisms available for low power SRIMs. The most basic ways to control the speed of a slip ring induction motor is either from the STATOR OR ROTOR SIDE. The mechanism employed here is to control the speed via a Single thyristor acting as an ON/OFF switch at the rotor side of this slip ring induction motor. The core scheme here is to control the high power machine by directly varying the load current or the rotor side current by the single thyristor after conversion of the available load side current into the DC current by a 3 phase RECTIFIER BRIDGE made of 6 diodes respectively. Thus, all the AC power is converted into simple DC current and is controlled by the thyristor ON/OFF time giving the required speed control as the rotor current is directly proportional to speed and torque in an increasing power scenario as in this case. Even the losses due to non-slip power recovery can be considerably neglected because of the machines high power status. Thus, we are able to simply control a high power SRIM by just varying the amount of ON/OFF time of the thyristor at the rotor end efficiently. Thus, this method is best suited for very high inertia loads, which requires a pull-out torque at almost zero speed and accelerate to full speed with minimum current drawn in a very short time period.

REVIEW OF LITERATURE ON INDUCTION GENERATORS AND CONTROLLERS FOR PICO HYDRO APPLICATIONS

Operation of Induction motors as induction generators in grid connected and self excitation mode is well known. In many countries induction generators are used for electrical power generation by wind energy. Low cost, robustness and ease of maintenance are attractive features of induction generators. Even though these generators are used at some places for micro hydro power generation, very small scale generation known as pico hydro generation offers excellent opportunity for them. Slip ring induction motors are used for micro power generation and squirrel cage induction motors are used for pico power generation. These generators have an inherent problem of terminal voltage variation with increase in load. Several different types of controllers are developed and tested. This paper presents a review of literature related to the present status of research work on self excited induction generators (SEIG), their terminal voltage control strategies and their applications.

An Alternative to Squirrel Cage Induction Motor for Electric Traction for Indian Railways – a Theoretical Cost saving Approach

Traditionally, the DC Series Motor was used for Electric Traction for reasons like high starting torque and easy speed Control. With the Advancement in control mechanism 3-ph Squirrel Cage Motor is being used currently with an AC-AC Drive. A new Cost saving approach is suggested in this paper with the use of Slip Ring Induction Motor for Indian Railways which is switching over to fully electrified routes.

Modeling and Simulation of a Large Chipper Drive

This paper presents a simulation model for a large chipper drive used in a paper mill. If the chipper drive is a slip ring induction motor, several advantages arise from using a rheostat in the rotor circuit. This paper will investigate the impact of a rotor circuit rheostat with respect to starting behavior and heavy duty load impulses. The chipper drive is modeled in Modelica, an object oriented multi domain simulation language. In addition to the theory, a practical case is presented to demonstrate the applicability of the derived knowledge.

Space and time harmonics related problems and their mitigation for position and speed sensorless slip-ring induction motor drives applications

There have been renewed interests in slip-ring induction machines due to their increasing use in both grid connected and stand-alone wind power generation schemes. Despite the squirrel cage induction generators’ advantages of being brushless, low-cost, needing less maintenance and having inherent overload protection, the biggest advantage of variable-speed wound rotor induction machines is in its doubled energy capture. Also in high power induction motor drives such as static Kramer drives or static Scherbius drives use of wound rotor induction motors is a must. Thus it becomes necessary to measure the speed of the machine for closed loop control for such high performance drives. Recently, a sensorless position and speed estimation scheme was proposed for wound rotor wind power generator. In this paper, the limitation of the scheme caused by space and time harmonics have been investigated. Simulation results have been presented to explain the mechanism of the space and time harmonics caused distortion of current. Experimental results showing the deterioration of speed detection scheme at light load for a slip-ring induction motor have been presented. Finally, improvements have been applied experimentally to obtain better speed estimation.

Direct Torque and Frequency Control of Double-Inverter-Fed Slip-Ring Induction Motor Drive

A novel sensorless scheme for direct torque and frequency control of a double-inverter-fed slip-ring induction motor is presented. The analysis of a double-inverter-fed induction motor is given to derive the proposed controller. Various frequency profiles are analyzed for a direct frequency controller. A novel frequency profile is suggested to make the sensorless drive operation reliable and machine parameter independent at any rotor speed. Simulation and experimental results are presented from a 50-hp drive, demonstrating that the drive can deliver full torque from 0 to 2-p.u. speed in either direction. Thus, double the rated power can be extracted from the motor without overloading it.