Induction Motor Starting Research Articles

Modeling of Induction Motor Direct Starting with and without Considering Current Displacement in Slot

This article presents a mathematical model of three-phase induction motor (IM) with a squirrel cage rotor and investigates its starting modes. Specifically, two scenarios are considered: direct starting of an IM and direct starting considering the current displacement effect in the rotor slots. Analyzing the starting modes of an IM without the use of automatic control systems is crucial for ensuring reliable, efficient, and safe operation of equipment across various industrial and commercial sectors. Understanding and accounting for the processes occurring during the starting mode of an IM allows for minimizing risks, enhancing energy efficiency, and reducing operational costs. This article details the mathematical modeling methods used for analyzing these starting modes and the results obtained from the modeling. These results were compared with data obtained experimentally, allowing for the assessment of the accuracy and reliability of the proposed model. The conducted research highlights the importance of considering current displacement in the rotor slots for accurate modeling and analysis of induction motor starting modes, particularly in capturing the differences in the amplitudes of the starting current and the faster transition to steady-state operation. Conclusions drawn from the comparison of modeling and experimental data provide valuable insights for the further development of control and operation methods for induction motors.

Study on Installation of Power Factor Correction Capacitor and Self-Excitation Phenomenon in Reactor Starting Induction Motor

Study on Installation of Power Factor Correction Capacitor and Self-Excitation Phenomenon in Reactor Starting Induction Motor

A novel power quality improved AC voltage controller for soft starting of squirrel cage induction motors

A novel power quality improved AC voltage controller for soft starting of squirrel cage induction motors

Power Compatibility of Induction Motors in Industrial Grids Containing Synchronous Generators

Starting an induction motor causes voltage sag in the industrial grid that may disturb the operation of grid equipment. Direct-on-line starting is the simplest and most cost-effective method for starting induction motors, but also the most problematic. Large industries often use internal power plants with synchronous generators and starting powerful motors may impact the generator operations. The synchronous generators could be operated with the automatic or manual mode of voltage control. As the operation experience proves, the generator voltage control mode has a significant impact on the transient behaviours in the industrial power grid when starting a large induction motor. This article presents a case study of the synchronous generator tripping within a true medium-voltage industrial grid during the direct-on-line starting of a large induction motor driving the feed water pump. An analysis of the generator protection logs after the tripping showed that the synchronous generator was controlled in manual mode and its protection relay settings were exceeded. The transients initiated by induction motor starts were studied for possible configurations and operating conditions of the grid using a model developed on the Matlab/Simulink Software platform. The simulations have shown that concern about starting large motors in industrial grids containing internal synchronous generators needs to be solved considering the grid configurations and the coordination of generator protection and control devices.

About Direct Start of Induction Motor with Two-Stage Reactive Power Compensation as a Part of the Auxiliary Drive of Electric Locomotive

The auxiliary electric drive of electric locomotives is often built on the basis of three-phase induction motors. In a number of auxiliary drive circuits, direct starting of motors is practiced, which is accompanied by significant starting currents. This imposes increased requirements on the installed power of the supply converter. A method for reducing starting and operating currents through the use of three-phase capacitor banks is considered. The simulation results are presented.

VFD-Based Coordinated Multi-Stage Centralized/Decentralized Control to Support Offshore Electrical Power Systems

This paper proposes a coordinated multi-stage centralized/decentralized control used to mitigate voltage fluctuation caused by planned direct on-line heavy induction motor start in oil and gas offshore platform. The proposed control remotely coordinates the active front-end variable frequency drives (AFE-VFDs) using a low-bandwidth communication link. It is split into three stages, in which stage 1 accurately regulates the power factor at the main feeder, stage 2 is a transitioning operating mode and stage 3 comprises the autonomous volt-var function to mitigate voltage fluctuation. The proposed control shows a centralized architecture for stages 1 and 2, and a decentralized architecture for stage 3. The proposed control is evaluated by means of simulation results considering a real case test bench of a Brazilian offshore platform, being comparatively confronted with two other literature solutions. Compared to other solutions, results show 33% and 29% of improvement in sag and swell voltage regulation at the main feeder, respectively; relief the generator field windings up to 8%, in steady state; and increase the power factor at the generator terminals from 0.92 to 0.97, using two AFE-VFDs.

Performance Analysis and Control of a Capacitor Start Induction Motor

Abstract: This paper presents an experimental study on the performance characteristics of a capacitor start induction motor. The objective of the study is to understand the starting torque, starting current, and speed control of the motor under different loads and input voltages. The experimental setup consists of a capacitor start induction motor, a tachometer, an ammeter, a voltmeter, a wattmeter, and a load. The motor is started by applying the input voltage to the stator winding, and the centrifugal switch disconnects the starting winding after the motor reaches a certain speed. The capacitor provides a phase shift in the current and voltage waveforms, which helps to start the motor. The motor performance is measured using the tachometer, ammeter, voltmeter, and wattmeter, and the data is analyzed to understand the efficiency and performance characteristics of the motor. The experimental results show that the motor can provide a high starting torque and efficient speed control with the use of a capacitor. The study provides practical insights into the performance characteristics and control of the capacitor start induction motor, and can be used to improve the energy efficiency of the motor in various applications.

Predictive Firing Algorithm for Soft Starter Driven Induction Motors

Soft starters are a well-known solution for starting induction motors in industrial applications. With a predictive algorithm approach the losses in motor and soft starter can be lowered significantly. This article presents an algorithm which can be implemented in industrial devices with a concomitant speed control option. This speed control is necessary to fit the users requirements for start-up. Besides the speed control, the characteristic behavior of the predictive algorithm is analyzed in detail. The suitability of the novel predictive closed loop approach for different representative industrial applications is proven by measurements and discussed in detail.

Modeling soft start of belt conveyor induction motor

Modeling soft start of belt conveyor induction motor

Starting of induction motor fed with stand-alone DFIG

This paper presents dynamic simulation and control of stand-alone doubly fed induction generator (DFIG) loaded with 3-phase induction motors (IMs). The study reveals that direct on-line starting of large IMs causes a large voltage sag across the generator terminals as the starting current drawn reaches up to 8-9 times the rated load current. Traditionally, this problem has tackled by oversizing of the generator or employment of special starters, under the pretext of mitigating voltage sag. This work explores ways that the starting current can be reduced economically by applying constant V/f control side by side with indirect field-oriented control (FOC) applied on the rotor side converter of the DFIG. This methodology enables starting of larger IMs and mitigation of voltage sag that occurs during the start-up period. Two different rating of IMs loaded with speed-squared mechanical torque are mainly considered. Simulation results of the system behavior under study confirm the capability of the proposed control.

Differential positive sequence power angle-based microgrid feeder protection

Abstract Integration of distribution generation (DG) makes the growth of the microgrid protection scheme very challenging issues. Researchers from all over the world continuously are doing hard work for developing the microgrid protection schemes. A differential positive sequence power angle (DPSPA) based microgrid protection scheme is proposed in this paper using positive sequence (PS) components of voltages and currents. The DPSPA for the feeder is calculated considering both ends of voltage and current signal information, when it is more than threshold, internal fault is reported otherwise, it is an external fault. Taking into consideration the varying operational modes of the microgrid, variations in DG penetration, and variations in fault variables namely fault types, and fault locations, the proposed protection scheme is verified on a modified IEEE-13 bus feeder. Moreover, to test the robustness and efficacy of the suggested scheme, various non-faulty events including induction motor starting, non-linear loading, load switching, capacitor switching, and section cutoff have been conducted. The proposed scheme is also verified for external faults and it is found that it continues to be stable for the external faults. The findings exhibit this proposed scheme, which is based on DPSPA, can successfully protect the microgrid under changing operating conditions.

Online Identification of Underlying Causes for Multiple and Multi-Stage Power Quality Disturbances Using S-Transform

ABSTRACT The proposed methodology aims at the identification of multiple and multi-stage power quality (PQ) disturbances along with their underlying causes. To this end, a computationally efficient S-Transform with decision tree (DT) based online PQ monitoring algorithm has been presented in this paper. This online algorithm provides a sample-based analysis of 40-dB noisy multiple and multi-stage PQ disturbance signals simulated in MATLAB environment with the different combinations of underlying causes as per the IEEE-1159 standard. The features like residual voltage, instantaneous phase-angle jump (IPAJ), and number of zero crossings (NZC) have been extracted from the transformed contours, viz., maximum voltage amplitude versus time (MVAVT) and phase-angle versus time (PAVT). Henceforth, the accurate recognition of most common underlying causes like three-phase fault, induction motor starting, and capacitor bank energizing has been achieved. For the first time, an online PQ monitoring algorithm is effectively assessing the type and underlying cause of a multiple or multi-stage disturbance simultaneously. The proposed methodology has also been experimentally validated with real-time PQ disturbance signals acquired in the laboratory.

A novel source side power quality improved soft starting of three-phase induction motor using a symmetrical angle controller through pic microcontroller

A novel source side power quality improved soft starting of three-phase induction motor using a symmetrical angle controller through pic microcontroller

Lifting scheme‐based matched wavelet design for effective characterisation of different types of voltage sag

This study presents a novel scheme for designing biorthogonal wavelets matched to the voltage sag (VS) signals. Instead of using standard wavelets, matched wavelets designed in this study can extract more distinguishing features for better characterisation of sag signals, although this study proposes only the designing process of matched wavelets. The key method used for designing matched wavelets is the lifting scheme, which has never been reported in the literature for constructing matched wavelets for PQ signals. Besides using the lifting scheme, the proposed work preprocesses sag signals to make input signal of lifting scheme rich of sag-related information. During pre-processing, 1-D sag signal is first converted to 2-D form for capturing information of every small transition (which may be overlooked in 1-D form) and then made 1-D by ring projection to implement 1-D lifting scheme. In this way, biorthogonal wavelets have been well matched to every type of VS signal collected through the experimental setup simulating different line faults, induction motor starting, transformer energisation and heavy load starting. Also, the characteristics of designed wavelets are evaluated in a MATLAB environment using frequency response and pole-zero mapping in z-plane. Higher PSNR values during signal reconstruction proved outperformance of newly designed matched wavelets.

Analysis of electric drive systems for performance of driving and starting under load

Purpose. Perform an analysis of existing automated control systems of the electric drive and methods of forming the starting torque to determine the compliance of the selected system and method to the requirements for trouble-free mode of start and start of the technological mechanism in difficult conditions or breakaway and start under load..
 Methodology. Comparison of energy performance and capabilities of control systems and methods for the formation of starting torque, mathematical calculations, analysis of the properties of systems and methods in accordance with the requirements of technological operations during the start.
 Findings. To obtain the results of the analysis of the current methods of starting induction motors, autotransformer start was considered, which can significantly reduce the starting current, and also connect a capacitor with a reactance to reduce the current and increase the starting torque; the use of soft start with amplitude-phase control allows you to reduce the starting current and reached the absence of its impulses. The vector-pulse method of controlling the converting device increases the starting torque in the absence of an increase in starting current, such advantages have a quasi-frequency starting mode, but the application is limited by special technological equipment. Thyristor voltage regulator using the phase control method, despite its widespread use in control systems, has a low value of the starting torque. To carry out starting in difficult conditions, according to the results of the analysis of existing systems of controlled starting, it was found that a rational electric drive system for hoisting-and-transport mechanisms is a frequency-controlled electric drive system according to the "frequency converter - asynchronous motor" (FC - IM) scheme.
 Originality. For the first time it is proposed to improve the existing control systems of hoisting and transport mechanisms that perform start-up in difficult conditions when using the modes of movement to form the starting torque that exceeds the passport value by 3-4 times. Increasing energy efficiency based on increasing their efficiency, information content and data reliability. For the first time, the reasons for the shortcomings of existing control systems during start-up under load in modern production are analyzed.
 Practical value. The choice of a rational electric drive system for lifting and transport mechanisms is substantiated when starting in difficult conditions, which will provide maximum efforts in the transmission of a technological mechanism with permissible current and thermal overloads of asynchronous machines.

A Proposed ANN-Based Acceleration Control Scheme for Soft Starting Induction Motor

In this article, a new soft starting control scheme based on an artificial neural network (ANN) is presented for a three-phase induction motor (IM) drive system. The main task of the control scheme is to keep the accelerating torque constant at a level based on the value of reference acceleration. This is accomplished by the proper choice of the firing angles of thyristors in the soft starter. Using the ANN approach, the complexity of the online determination of the thyristors firing angles is resolved. The IM torque-speed characteristic curves are firstly used to train the ANN model. Secondly, the IM- soft starter system is modeled using MATLAB/SIMULINK. To prove the effectiveness of the proposed ANN-based acceleration control scheme, different reference accelerations and loading conditions are applied and investigated. Finally, a laboratory prototype of 3 kW soft starter is implemented. The proposed control scheme is executed in a real-time environment using a digital signal processor (Model: TMS320F28335). The simulation and real-time results significantly confirm that the proposed controller can efficiently reduce the IM starting current and torque pulsations. This in turn ensures a smooth acceleration of the IM during the starting process. Moreover, the proposed control scheme has the superiority over several soft starting control schemes since it has a simple control circuit configuration, less required sensors, and low computational burden of the control algorithm.

Evolving Disturbances Detection and Classification in Real-time for Grid-Connected System

In the past one decade, several signal processing techniques for detection and classification of single instant occurrence of both power quality (PQ) and islanding events have been reported. However, with the presence of several energy resources in the system, more critical conditions of PQ may arise due to transformer energizing, capacitor energizing, induction motor start, even fault at various locations of the network. As a result, evolving disturbances in a sequence may be observed. This study presents use of energy preserving ensemble empirical mode decomposition technique to detect evolving disturbances that occur in succession and classify them using least square support vector machine. The study is demonstrated on several cases of evolving disturbances as offline analysis for signals simulated in PSCAD/EMTDC and its analysis in MATLAB. Furthermore, novelty in study is established with real-time implementation of techniques in field programmable gate array blocks for detection and classification of evolving disturbances. Also, comparison with existing techniques is included in the discussion section.

A convex model for induction motor starting transients imbedded in an OPF-based optimization problem

Large horsepower induction motors play a critical role in the operation of industrial facilities. In this respect, the distribution network operators dedicate a high priority to the operational safety of these motor loads. In this paper, the induction motor starting is modeled analytically and in a semi-static fashion. This model is imbedded in a convex distribution system restoration problem. In this optimization problem, it is aimed to determine the optimal status of static loads and the optimal dispatch of distributed generators such that: a) the induction motors can be reaccelerated in a safe way and, b) the total power of static loads that cannot be supplied before the motor energization, is minimized. The proposed optimization problem is applied in the case of a distribution network under different simulation scenarios. The feasibility and accuracy of the obtained results are validated using a) off-line time-domain simulations, and b) Power Hardware-In-the-Loop experiments.

Modeling and Analysis of a Six-Phase Self Excited Induction Generator Feeding Induction Motors

Conventionally, the multi-phase self-excited induction generators (SEIGs) have been analysed either with resistive or static resistive-inductive loads. This endeavor proposes a simple six-phase SEIG (6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG) topology feeding induction motors (IMs). Shunt and series capacitances provide excitation current and load voltage compensation for 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG. A stationary reference frame dual dq model including non-linear saturation and cross coupling effects is integrated with IM loads for simulating 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG-IM set. Sub-synchronous resonance (SSR) is associated with series compensated SEIGs. A series capacitance 2.5 times the excitation capacitance causes SSR in studied 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG as starting of IMs is attempted from its terminals. SSR induces low frequency oscillations and spikes load voltage and current amplitudes. A method to overcome SSR is proposed by evaluating a critical value of series capacitance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$C_{se,cr}$</tex-math></inline-formula> ). Equipped with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$C_{se,cr}$</tex-math></inline-formula> and excitation capacitance the 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG successfully sustains starting, no-load build-up and rated load operation of IMs. A comparison with its equivalent 3 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> counterpart reveals that 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula> -SEIG manages reactive power more efficiently as its optimum capacitance requirement reduces by 1.9 to 3.75 times, it incurs 0.4% to 2.8% lesser %THDs in output parameters and exhibits greater operational flexibility. Experimental results are obtained on an open end winding induction machine operated as SEIG.

Design Phase Delay Control for Soft Starting 3 Phase Induction Motor

Induction Motor is one type of electric machine that is widely used both in household consumers and industrial players. However, induction motors have drawbacks, namely starting currents that can reach 5-7 times the nominal current, of course this can lead to reduced life time of other electrical equipment and the possibility of shutdown or trip is very large. This research proposes a new modeling to create a soft starting system to reduce the 3 phase induction motor start current. This system was built with the help of a Phase Delay Control power electronics circuit with the main component, Triac, which functions to regulate the input voltage of a 3 phase induction motor and a contactor whose function is to move the 3 phase induction motor power supply from the soft starting system to the PLN source directly if, The input voltage is the same as the nominal voltage. The output of these processes is the Triac ignition angle, so during the starting process, the induction motor will receive an input voltage in stages from the smallest to reach its nominal voltage. Thus the results of testing the soft starting system that is designed to have a maximum current value at the start of 2.45 A or 77.58% lower than the start current using the DOL method with a value of 10.93 A at no-load conditions and 7.41 A or 34.19% lower than the motor starting current with the DOL method with a value of 11.31 A when the motor is loaded.