ANALYSIS OF THE STATIC ERROR OF A CHARGING AND DISCHARGING DEVICE FOR HIGH-CAPACITY LITHIUM-ION BATTERIES

В качестве оборудования ресурсных испытаний аккумуляторных батарей используется зарядно-разрядное устройство (ЗРУ). В данной статье проведен анализ статической погрешности ЗРУ, определена методическая ошибка, а также предложена методика определения коэффициентов разомкнутых контуров. The charging and discharging device (CDD) is used as the equipment for carrying out service life tests of accumulator batteries. In this article, we perform the analysis of the static error of the CDD, determine the methodological, and propose a method for determining the coefficients of open contours.

Control Strategy of Photovoltaic Grid Connected System Based on PI and QPR Double Closed Loop Control

The traditional proportional integral (PI) controller in photovoltaic three-phase inverter system has the problems of no static error tracking and poor resonance suppression effect. In order to improve the resonance suppression effect and current control effect of photovoltaic three-phase inverter system, a control strategy of photovoltaic three-phase inverter system based on PI and quasi proportional resonance (QPR) double closed-loop control is proposed. The control strategy and control block diagram based on PI and QPR double closed-loop control are designed to realize no static error tracking of incoming current, which has better waveform of incoming current and resonance suppression effect, and improves system stability. Finally, the effectiveness of the control strategy are verified by simulation.

Dynamic Modelling and Performance Optimization-Based Sliding Mode Control of Process Drying in a Convective Tunnel Dryer

In this work, we thoroughly investigate the use of sliding mode control for nonlinear systems, specially its application for the control of dryer designed for drying food products. A dynamic model of the drying process has been developed, experimental measurements presented in this paper are established for different values of drying air temperature and drying air velocity. Two scenario of sliding mode control applied to the hybrid tunnel dryer has been assessed through simulations. At first, a nonlinear sliding mode control with first order sliding surface was tested. In front of the insufficient performance of this control in terms of the presence of chattering phenomenon and static error, it was decided to apply a nonlinear sliding mode control with PI sliding surface. Simulation results show that this latter control approach can obtain excellent control performance with no chattering problem, reducing of static error and a good tracking of trajectory.

Dynamic Modelling and Performance Optimization-Based Sliding Mode Control of Process Drying in a Convective Tunnel Dryer

In this work, we thoroughly investigate the use of sliding mode control for nonlinear systems, specially its application for the control of dryer designed for drying food products. A dynamic model of the drying process has been developed, experimental measurements presented in this paper are established for different values of drying air temperature and drying air velocity. Two scenario of sliding mode control applied to the hybrid tunnel dryer has been assessed through simulations. At first, a nonlinear sliding mode control with first order sliding surface was tested. In front of the insufficient performance of this control in terms of the presence of chattering phenomenon and static error, it was decided to apply a nonlinear sliding mode control with PI sliding surface. Simulation results show that this latter control approach can obtain excellent control performance with no chattering problem, reducing of static error and a good tracking of trajectory.

Development of a generalized mathematical model of static error electromechanical measuring equipment

To keep military equipment fit for use, carry out maintenance activities, an important and integral part of which is metrological service. The effectiveness of metrological services depends on the completeness of the coverage of the monitored parameters, frequency and reliability of their measuring control. The most common, at present, when controlling the parameters of military equipment are electromechanical measuring equipment. The main metrological characteristic of electromechanical measuring instruments in a static measurement mode is the nominal calibration characteristic. During operation, the calibration characteristic of electromechanical measuring instruments, under the influence of various factors, has deviations from the nominal, which leads to an instrumental static error. The article deals with the applied aspects of assessing the static error of electromechanical measuring equipment, which is expressed through the sensitivity or static transmission coefficients of measuring transducers. Based on the results of the analysis, a generalized mathematical model of the relative static error of electromechanical measuring equipment for various structural schemes of connecting measuring transducers was obtained. It is proposed to apply a generalized mathematical model to assess the relative static error of electromechanical measuring instruments (with various structural schemes) during their operation. The use of an updated static error will allow to refine the calibration characteristics of electromechanical measuring instruments, which in turn will lead to obtaining reliable information about the state of military equipment during metrological maintenance and immediately before use.

VHDL design and FPGA implementation of direct torque control for induction machines

This paper presents a VHDL design and an FPGA implementation of a direct torque controller (DTC) used to order induction machines (IM). The use of FPGA at high sampling frequency reduces the torque ripple while maintaining the classical DTC control structure. We have adopted a modular approach, by dividing the global entity into a set of elementary blocks designed and implemented separately. The performances of this command are to reduce the torque ripple to 0.01 Nm and the flux ripple to 0.01 wb with a circuit implementing DTC control of 3,256 LEs of complexity and 64 latency clock cycles. To evaluate the performance of our FPGA circuit implementing DTC controller, we have performed a co-simulation platform based on MATLAB/Simulink and Modelsim programs. MATLAB/Simulink was used to simulate the dynamics of the induction machine associated with its inverter and the proposed DTC control strategy was executed under the modelsim software using the VHDL fixed point. We have operated our circuit FPGA in the loop in a speed variation platform of induction machine and we have obtained the following performances: A zero overrun, response time at speeds of 300 ms and a zero static error as required in the specifications.

Study of Steady-State Periodic Motions of Crawling Robot Modules under External Disturbances

The development and design of a multi-module crawling robot requires an elaboration of each aspect of its motion in the implementation of various tasks, including holding the position of such a robot under a driving force. This problem has been solved for a three-module crawling robot, one of the end supports of which was fixed on the surface, and the other was affected by the harmonic external force changing according to the meander law. For this purpose, a module control system based on the CTC controller has been proposed. Numerical simulation has been used to study the quantitative and qualitative characteristics of robot module vibrations depending on the ratio of the amplitudes of the vertical and horizontal components of the force and the phase mismatch between them. It is found that when the external force vertical and horizontal amplitudes are equal, the module angles fluctuate relative to the set values, and when there is a certain ratio between the amplitudes, a static error appears which increases as the specified ratio moves away from 1.

Fractional-order sliding mode controller for the two-link robot arm

In this paper, the author proposes a sliding mode controller with the fractional-order for the two-link robot arm. Firstly, the model and dynamic equations of the two-link robot arm are presented. Based on these equations, the author builds the controller for each joint of the robot. The controller is a sliding mode controller with its order is not an integer value. The task of the controller is to adjust the torques acted on the joints in order for the angular coordinates of each link to coincide with the desired values. The effectiveness of the proposed control system is demonstrated through Matlab-Simulink software. The robot model and controller are built to investigate the system quality. The results show that the quality of the control system is very high: there is not the chattering phenomenon of torques, the response angles of each link quickly reach the desired values, and the static error equal to zero.