Soft Starting System Research Articles

Measures to increase the technical resource of electrical equipment of powerful irrigation pump stations

RELEVANCE. At present, unstressed systems for launching high-voltage electric motors have been increasingly used. These systems limit the values of starting currents as well as eliminate alternating oscillations of engine electromagnetic torque. THE PURPOSE. Development of measures to improve the technical resource of electrical equipment of powerful irrigation pumping stations based on the use of soft start systems for high-voltage electric motors. METHODS. In the course of the study, methods for analyzing the technological processes of a pumping station, methods for mathematical and computer modeling of an electric drive were used. RESULTS. Computer models have been developed to study the regime characteristics of asynchronous and synchronous electric drives of pumping stations with direct and soft start of electric motors. A shockless start-up system for high-voltage electric motors of irrigation pumping stations of the first lift based on a current inverter is proposed. CONCLUSION. The reliability and durability of electrical equipment depends primarily on the technical resource, which is determined by a number of factors. The main factors influencing the technical life of the electrical equipment of large irrigation pumping stations are the transient modes that occur when the pumping units are started. The soft start system of high-voltage electric motors of irrigation pumping stations proposed in this article makes it possible to eliminate the negative impact of transient conditions on the operation of electrical equipment and, thereby, increase the technical resource and reliability of the power supply system of the pumping station as a whole.

Technical and economic justification for application of a soft start system for high-voltage electric motors of pumping units

THE PURPOSE. Development of a methodology for conducting a feasibility study when using a soft start system based on a current inverter for high-voltage electric motors of pumping units of irrigation pumping stations of the first lift.METHODS. Research and calculations were carried out in accordance with the algorithm for compiling the energy balance of pumping units, as well as using the analysis of statistical data.RESULTS. A feasibility study is presented for the feasibility of introducing soft start systems for irrigation pumping stations of the first lift, where, as a rule, powerful synchronous electric motors are installed. A method for determining the economic efficiency of systems or soft starters for electric drives of pumping stations is proposed. The rational use of an alternative soft starter based on a current inverter is substantiated.CONCLUSION. Determining the economic efficiency of introducing soft starters remains a difficult task, since the operating conditions of facilities require taking into account various influencing factors that are not always amenable to accurate assessment. This is the problem of developing a universal methodology for assessing the economic efficiency of introducing soft starters. The proposed methodology for determining the economic efficiency of such systems, based on known methods, complements and simplifies the process of calculations and computational algorithms.

Research on Segmented Belt Acceleration Curve Based on Automated Mechanical Transmission

An automated mechanical transmission (AMT) is proposed as a new soft starter for medium-scale belt conveyors in this paper. The AMT is used to start the belt conveyor and shift gears step by step to make the belt conveyor accelerate softly. Based on analyzing common soft-starting acceleration curves, a segmented belt acceleration curve is proposed as a new soft-starting acceleration curve. By analyzing the AMT soft-starting system, the system modeling is built and the AMT output shaft’s angular acceleration is proposed to be controlled to control the belt acceleration. The AMT soft-starting simulation model is established in the environment of AMESim, and simulation results of the soft-starting process from the first to eighth gear positions are given. The main parameter curves of the AMT soft-starting system including the belt, driving pulley, and AMT output shaft are analyzed. The simulation model can indicate the viscoelastic property of the belt. The simulation results prove that the segmented belt acceleration is appropriate for a medium-scale belt conveyor and provide a theoretical and reasonable basis for using an AMT as a soft starter.

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.

Speed control of 3-phase induction motor using rotor impedance

This paper introduces a method of rotor impedance control by using controlled capacitor/inductor connected in series in the rotor circuit. The proposed system can be operate as a speed control system or a soft starting system to limit the starting current of the motor. An approach to a three MOSFETs-based a rotor circuit of induction motor is presented. The experimental realization of the drive posed some serious problems, notably with regard to the successful driving pulses of MOSFETs over a wide speed range. Analysis of the secondary MOSFETs-controlled motor raised many interesting challenges. It was decided to use an equivalent circuit approach to the analysis because the primary voltage and current were both largely sinusoidal. The equivalent circuit used is based on the single-phase equivalent of a balanced sinusoidal three-phase system. The effective value of the external rotor inductance or capacitance is calculated. Moreover, the motor performance specially speed, motor starting current, and torque during the control of duty cycle of MOSFETs are studied. Also, MOSFETs performance has been studied. Closed loop speed control of the motor speed have been investigated using hysteresis control based on controlling MOSFETs duty cycle. Experimental results have been carried out in the Laboratory to verifying the analysis. The simulation results are given and proved to yield good agreement when compared with the experimental results.

Адаптивний електротепловий захист напівпровідникових перетворювачів електроенергії

Thermal management for power converters during normal operation and transient modes when electrical components are warmed up is an actual problem. This can be particularly important for converters with intermittent duty operation, e.g. power supplies for resistance welding. According to some research, nearly 60% of failures are temperature-induced, and for every 10°C temperature rise in operating environment the failure rate nearly doubles. In this paper, thermal motion of state equations eigenvalue is analyzed. It is shown, that in semiconductor converters with an output smoothing filter it is appropriate to use thermal protection devices based on thermal normalization of the converter filter and, while for cases when short circuits are possible it is appropriate to use a soft start system with thermal adaptation for soft start time factor. Based on these results, two systems of thermal protections operating for semiconductor power converters are introduced. Simulation of combined electromagnetic and thermal processes in buck converter operating with both thermal management systems in overlapping environments MATLAB/Simulink and PLECS showed the possibility to significantly reduce thermal shock on semiconductor components. Using the system of filter parameters normalization decreases the temperature of the crystal from 210°C to 85°C, using the adaptive soft start system decreases the temperature from 180°C to 80°C. The simulation results are confirmed by tests on real devices.

Angular Velocity's Neural Network Observer of the Electric Drive of TVR - IM Type Implemented in Software Environment LabVIEW

One of the common ways to manage a smooth starting and stopping of asynchronous motors are soft-start system. For this provision is necessary to use a closed speed asynchronous electric drive of tiristor voltage regulator - induction motor (TVR-IM) type. Using real sensors significantly increases the cost of installation and also introduces a number of inconveniences in the operation of the actuator. Observer has clear advantages that are created on artificial neural network. Creating a neural network observer in program graphic programming LabVIEW will allow to evaluate the speed of rotation of the asynchronous electric.

Building the Structure and the Neuroemulator Angular Velocity's Learning Algorithm Selection of the Electric Drive of TVR-IM Type

Today, one of the most common ways to control smooth starting and stopping of the induction motors are soft-start system. To ensure such control method the use of closed-speed asynchronous electric drive of TVR-IM type is required. Using real speed sensors is undesirable due to a number of inconveniences exploitation of the drive. The use of the observer based on a neural network is more convenient than the use of the real sensors. Its advantages are robustness, high generalizing properties, lack of requirements to the motor parameters, the relative ease of creation. This article presents the research and selection of the best learning algorithm of the neuroemulator angular velocity of the electric drive of TVR-IM type. There were investigated such learning algorithms as gradient descent back propagation, gradient descent with momentum back propagation, algorithm of Levenberg – Marquardt, scaled conjugate gradient back propagation (SCG). The input parameters of the neuroemulator were the pre treatment signals from the real sensors the stator current and the stator voltage and their delay, as well as a feedback signal from the estimated speed with delay. A comparative analysis of learning algorithms was performed on a simulation model of asynchronous electric drive implemented in software MATLAB Simulink, when the electric drive was running in dynamic mode. The simulation results demonstrate that the best method of learning is algorithm of Levenberg – Marquardt.

Modeling and Simulating of Frequency Conversion Soft Start System Based on SPWM

Since over large starting current makes an instant giant grid voltage drop and contacting with current spark can damage the starting device when three phase asynchronous motor is directly started, in order to reduce the impact on the grid and the motor caused by the over large starting current, the present disclosure provides a frequency conversion soft start system based on SPWN. Control system generates IGBT controlled by SPWM pulse control using the regular sampling II method, thus achieving an AC infinitely approaching to a sine wave to open-loop control the motor and implement soft start. The method of frequency conversion soft start based on SPWM may implement a smooth start of the motor with lesser starting current and larger starting torque, thereby largely reducing the impact on the grid voltage and the motor. The experimental results showed that the method of frequency conversion soft start based on SPWM effectively reduces the starting current and implements the motor’s smooth start.

A Kind of Discrete Variable Frequency Heavy-Load Soft Start System

A kind of discrete variable frequency heavy-load soft start system was designed in order to realize heavy-load soft starting of motor. It consisted of variable reactance converter, discrete variable frequency converter and controller. The system structure was described in detail and the principle of discrete variable frequency heavy-load soft starting was analyzed. Also the model of the system was made and simulation of the system was done. The simulation results proved that the system can not only start motor smoothly, but also increase the motor start torque greatly, thus heavy load soft-starting of motor can be realized perfectly. In addition, the experiment of the system was done. The experiment results proved that the simulation was correct and the designed discrete variable frequency heavy-load soft start system can realize heavy-load soft start of motor. DOI : http://dx.doi.org/10.11591/telkomnika.v12i4.4930

Selected Problems of the Asynchronous Drive Control with the Three-Phase Soft-Start System

The paper presents a design of a computer measuring system for the recording and visualisation of selected parameters of an AC motor. Such parameters are characterised and the principles of their configuration are stated for a three-phase soft-start system. The measuring experiments were performed on the drive during the start-up. The results are represented as time characteristics of the phase to-phase voltage, of phase current and of rotational speed.

Analysis and Comparison of Soft-Start Systems Applied to Belt Conveyors

For soft-start system of for belt conveyor with long-distance and high-power, this essay, combining with lots of mechatronics research, design, application and commissioning work related with belt conveyor, researched and analyzed structure and governor principle of soft-start devices or systems successfully applied in coal mines or other industries. Furthermore, it evaluated each type of soft-starters in technical and economic aspects, which will play a guiding role in reasonable selection and application of soft starting devices.

Study of an Original Regulating Voltage Soft-Start Method

Reliable soft-start system is crucial to smooth and safe operation of belt conveyor. Therefore, based on analysis of behaviors of the three-phase asynchronous motors’ reduced voltage starting and ordinary hydraulic coupling independently applied to the conveyor belt, this essay proposes an original method of regulating voltage soft-start, introduces the principle and process of soft start, and determines strategies on power balance among several motors.

The Analysis of Soft Starting System of Brushless Excitation Synchronous Motor

This paper studies the synchronization of brushless excitation frequency soft start system design. On the basis of principle of the synchronized machine brushless excitation frequency soft starter system, the practical applications of brushless motor control system are elaborated. Experimental results in engineering show effectiveness of the design.

Pump station combined control based on high-voltage electric drives

The construction of a combined system of pump-station control based on a high-voltage frequency-regulated drive and high-voltage soft-start system is described. It is shown that, using special algorithms in control systems allows one to implement a very efficient and reliable technological complex with high performance capabilities at minimal cost.