Modeling the system of a dovetailless asynchronous electric drive for conveyor mechanisms

The article considers a vector control system for asynchronous electric drive of belt conveyors, which uses an adaptive observer to control the speed of the electric drive. This allows you to increase the reliability and inter-interval maintenance of the electric drive. The requirements for the observer are determined, its mathematical description is made, and the law of adaptation is determined. In the Matlab Simulink package, a computer simulation of the proposed sensor-free control system is performed. A study of the robustness of the actuator in terms of the drift of the parameters of the motor when powered from the inverter, expressed by the integral criterion for parametric robustness. Based on the results obtained, a comparison is made and conclusions are drawn about the advantages and disadvantages of using an adaptive observer in comparison with other types of observers.

Improving of the vector control system structure of the active controlled rectifier

The vast majority of electricity is used by industrial facilities in a converted form. At the same time, the use of semiconductor converters to obtain the required load parameters is intensively increasing. Current trends in the development and improvement of semiconductor converters are aimed at energy saving by improving their quality of work and reducing the impact on the power supply, load, and related consumers. Frequency converter with DC insert has become widespread and widely used. Its scheme is mainly based on an uncontrolled diode rectifier and an autonomous voltage inverter. Uncontrolled rectifiers are simple and reliable, but have two main disadvantages: the impossibility to recover electricity to the supply network and distortions of the source current shape. We can get rid of these disadvantages by using an active rectifier made according to the voltage source scheme instead of an uncontrolled rectifier. The operation of an active rectifier significantly depends on the type of its control system structure. This article aims to to improve the structure of the switches control system of the active rectifier scheme – voltage source built using a vector calculation algorithm; creation of a MatLab model of a three-phase active-controlled rectifier operating with a fixed modulation frequency and analysis of the influence of the input inductance value on the quality of its operation. The simulation results confirm that the improved structure of the vector control system proposed by the authors ensures high-quality operation of the active rectifier and electromagnetic compatibility of the frequency converter with the power supply network at the level allowed by the standards; simplification of the representation mathematical apparatus of the generalized vectors of currents and voltages at the construction of a vector control system of the active rectifier – voltage source practically did not influence qualitative indicators of the converter work in any way; a network filter must be used to eliminate the final distortions introduced into the source voltage by an additional nonlinear load.

Vector control system of electric traction drive with power losses minimization

Based on the operating conditions analysis of electric traction drives of locomotives, it has been established that the vector control systems for an asynchronous motor fully satisfy all the requirements. On the basis of a T-shaped equivalent circuit, a mathematical model of an induction motor is presented, taking into account losses in the stator steel, the effect of the rotor current and saturation displacement. An algorithm for the formation of the optimal, from the point of view of power losses, task for the rotor flux linkage when using a vector control system with the orientation of the axes of the coordinate system along the rotor magnetic field, is developed. The limiting factors are the limitations on the current and voltage of the motor stator, the diesel generator set power. A shared control system for an electric traction drive with asynchronous motors has been developed, which provides direct control of wheel slip with a subordinate vector control system that minimizes power losses. The results of modeling in a steady-state operation and a start-up mode for an electric traction drive of a two-axle bogie with axial support and 630 kW asynchronous motors with the use of various options for organizing circuit reentrances are presented.

Vector control system of electric drive of grain machine conveyor

Purpose. Synthesis of an automatic control system for an asynchronous electric drive of a grain thrower conveyor based on a frequency converter with vector control. Methodology. The research was carried out using methods of mathematical modeling of an electric drive; using methods of tuning optimization and regulator synthesis. The technique of synthesis of vector control systems is based on the representation of a non-stationary multi-connected object, which is an AC machine, in the form of a set of stationary subobjects with linear links in the main control channels. Findings. The study of the work of the subordinate regulation system, which implements the principles of vector control, oriented along the vector of the rotor flux linkage, has been carried out. The modeling of the processes of AM excitation, AM start-up at idle speed, nominal load surge, speed reduction has been carried out. It was found that the synthesized system is characterized by good quality indicators. The overshoot at start does not exceed 5%, the regulation time is 0.4 s, the torque limitation is carried out at a predetermined level. It has been proven that oscillatory processes in transient modes with significant torque surges with classical settings of loop regulators can be compensated by introducing artificial cross-links into the control part of the electric drive. Originality. A system of subordinate regulation of the blood pressure of the grain thrower trimmer conveyor has been implemented to set the speed of the grain flow with the aim of throwing grain at a given distance by creating an appropriate ballistic flight trajectory, which ensures a reduction in losses from damage to grain. Practical value. The structure of the vector control system of a frequency-controlled asynchronous electric drive with additional compensating cross-connections between active and reactive energy control channels is proposed to improve the quality indicators of the system.

Study of declination methods while forming the appearance of the surface-to-air unmanned aerial vehicle with a vertical start

The problem of choosing a rational declination system from alternative variants at the stage of forming the appearance of an unmanned aerial vehicle (UAV) with a vertical launch is considered. Currently, the vertical launch is becoming more widely used for surface-to-air unmanned aerial vehicles, which are considered in this paper. A characteristic initial part of the trajectory of such unmanned aerial vehicles is the declination to the required angular position over a short period of time. The UAV declination process requires the generation of relatively large control moments. Declination of surface-to-air UAVs is implemented by means of moment gas-dynamic control with two main methods – by using the thrust vector control system of the UAV main jet engine or by using special additional gas-dynamic devices. The alternative variants of declination systems for solving the problem under consideration are:– a thrust vector control system with gas rudders installed in the UAV engine nozzle or just behind its cut-off on special pylons;– a pulse propulsion system that creates the UAV declination moment by means of jets of micro-thrusters, which are activated by a special algorithm.In the comparative analysis of declination systems, the criterion for choosing the correct method of declination was the actual near border of the affected zone. The mass minimum of the projected UAV is accepted as the criterion for choosing a rational variant of the declination system. The main relations for calculating the main design parameters of the considered declination systems are given. The appearance parameters of the hypothetical surface-to-air UAV of medium range with alternative declination systems were calculated. A comparative analysis of the results obtained was carried out.

ANALYSIS OF THE OPERATING MODES OF THE SUSPENDED CABLE CAR ELECTRIC DRIVE USING THE VECTOR CONTROL SYSTEM

Continuous transport systems, including rope conveyors designed to move people and goods, are subject to very strict safety and energy efficiency requirements. As a rule, suspended cableways in operation have an unregulated electric drive with a smooth start system. Among the ways to meet these requirements is the use of modern regulated electric drives. The electromechanical system with a vector-controlled asynchronous electric motor is considered in the work. Based on the obtained model, within the framework of the MATLAB / Simulink application package, an investigation of the dynamic characteristics of the cableway electric drive was carried out. An analysis of the nature of the distribution of dynamic error in terms of speed and energy losses depending on the load and speed of movement of the rope traction element of the transport system is given. The results presented in the article make it possible to choose rational electric drives for continuous transport systems with rope traction elements. References 5, figures 5, table.

The efficiency of the active controlled rectifier operation in the mains voltage distortion mode

Goal. Checking the efficiency of the active rectifier with differences types of control systems in conditions of deep voltage distortions of a three-phase three-wire supply network. Methodology. The authors have used the Matlab/Simulink software environment to create a model of an active rectifier with various types of control systems as part of a frequency electric drive. We performed a series of simulations of the operating modes of an active rectifier with various control systems when the supply voltage is distorted. Results. When the active rectifier is operating in an unregulated mode, the distortions of the current and mains voltage exceed the maximum permissible values. The quality indicators of the mains current and mains voltage are significantly higher than the normally permissible values. In the absence of voltage distortions in the supply network, the operation of the active rectifier can effectively eliminate the distortions of the mains current, regardless of the type of control system of the active rectifier. In conditions of deep distortions of the supply network voltage, the operation of an active rectifier with a vector control system is more efficient than with a parametric control system. Originality. Criteria for determining the quality of consumed electricity at the connection point of the circuit are proposed. Practical significance. Recommendations have been developed for the use of active rectifier control systems when working with a distorted power supply voltage.