Adjustable Speed System Research Articles

A Space Vector Modulation Strategy for Improving Voltage Transfer Ratio of Multi-Phase Inverter

In the five-phase-inverter adjustable speed system, a five-phase two-level inverter usually adopts the nearest-two vector SVPWM (NTV-SVPWM) or the nearest-four vector SVPWM (NFV-SVPWM). The former one has a high-output-current harmonic, which increases the power losses, while the latter one has a low harmonic, but its sinusoidal voltage transfer ratio (VTR) is 0.812, which decreases load capacity. To improve the loading capacity and decrease the power losses of the five-phase-inverter adjustable speed system, a new space vector over-modulation method based on multi-vector weighting is proposed in this paper, and harmonic characteristics of the proposed over-modulation method are analyzed. The simulation results indicate that the proposed over-modulation method has a lower output voltage error than that with the traditional NFV-SVPWM and has a lower output current THD than that with the traditional NTV-SVPWM. The experimental results verify that the proposed method is correct and feasible.

Gear downshift control of inverse-automatic mechanical transmission of electric vehicle

In order to improve the driving dynamics and riding comfort of pure electric vehicles, taking a two-speed I-AMT (Inverse-Automatic Mechanical Transmission) with rear friction clutch as the research object, a gear shift strategy, which consists of the open-loop control of the clutch position control and the closed-loop control of the drive motor speed control, is proposed. Considering the inherent time-delay and external disturbances within the motor speed adjustment system, a two DOF (degree-of-freedom) Smith predictor with feedforward input is designed to track the target speed of the drive motor. The feedforward input is used to eliminate the influence of clutch sliding friction on the motor speed control, while the feedback speed tracking controller is applied to realize the speed tracking performance with the existence of time-delay and the external disturbance. In order to verify the effectiveness of the gear shift control strategy and the accuracy of the two DOF Smith controller with feedforward control, simulation results comparison is firstly carried out to illustrate the effectiveness of the control scheme. Then, a light pure electric vehicle equipped with I-AMT was used for downshift experiments under large throttle, which is the most difficult working scenario to control the transmission. The experimental results show that the two DOF Smith controller can eliminate the influence of time-delay on the closed-loop control, and the proposed whole gear shift control strategy can limit the clutch slippage time within 1.5 s, resulting in a smaller shift jerk, thus guarantee the driving dynamics and riding comfort simultaneously.

Speed control of the asynchronous motor using LabVIEW

This paper was presented a comparative study on the methods of adjusting the speed of a three-phase asynchronous motor with a rotor in a short circuit. For the same structure of the experimental stand used, two programs were created, implemented, and validated in LabVIEW. For the first method, the program in LabVIEW was made with the PI (proportional-integrative) controller and for the second method, the program in LabVIEW was made with the Fuzzy Logic controller. Following the analysis of the resulting graphs, it was found that the speed control system made with the fuzzy logic controller ensures an increase in its performance compared to the speed control system made with the conventional PI type controller. The indicial responses of the adjustment system of the three-phase asynchronous motor speed with PI controller or Fuzzy Logic controller have been determined in real-time by means of the experimental stand. The override of the speed adjustment system is decreased from the value of 26.9% corresponding to the PI controller to the value of 2.3% corresponding to the Fuzzy Logic controller and the duration of the transient time is decreased from the value of 2.2 s related to the PI controller to the value of 0.5 s, related to the Fuzzy Logic controller. By using the Fuzzy Logic controller, the amount of electrical energy required to supply the electric drive system made with a three-phase asynchronous motor will be reduced. This three-phase asynchronous motor speed adjustment algorithm can be implemented for other electric drive systems from different industrial applications.

Terminal sliding mode speed control method of permanent magnet synchronous linear motor based on adaptive parameter identification

In order to make the speed adjustment system of the permanent magnet synchronous linear motor more stable and make the convergence performance of the speed control system better, a speed regulator based on the terminal sliding mode algorithm is proposed. In addition, the permanent magnet synchronous linear motor will also be affected by temperature changes during its operation. Aiming to enhance the adaptability of linear motors to parameter changes, a terminal sliding mode speed control idea based on adaptive parameter identification is proposed. The Popov stability theory and the mathematical model of linear motor are used to construct a parameter identification system. The identification flux parameters are used as the control algorithm of the terminal sliding mode speed regulator and the update matching of speed regulator flux parameters and motor system parameters are realized. Through the above algorithm, the performance of the entire speed control system is improved. The results of simulation experiments can illustrate the effectiveness of this control method and its effect on improving the control performance.

基于FPGA的智能调速直流风扇设计

本文主要介绍一款基于FPGA的智能调速风扇系统。本系统采用两种控制方式，一是温度自动控制，二是传统的档位控制，采用KCD1船型开关进行切换，并配备夜间呼吸灯用以提高用户舒适度。本设计以FPGA为控制核心，采用DHT11温湿度传感器检测室内温湿度，8位数码管实时显示温湿度数据，同时辅以温度自适应转速调节控制算法输出PWM调制信号到L9110直流电机驱动模块用于驱动并调节直流电机转速，达到自动控制风扇转速的效果。此设计的创新点在于，本研究从传统的风扇出发，加装本设计系统就可实现智能控制，兼顾其便利与舒适。 This article mainly introduces an intelligent speed-adjusting fan system based on FPGA. The system adopts two control modes, one is automatic temperature control, the other is traditional gear control, which is switched by KCD1 ship type switch, and equipped with nighttime breathing lights to improve user comfort. This system takes FPGA as the control core, the DHT11 temperature and humidity sensor is used to detect the indoor temperature and humidity. The 8-bit digital tube displays the temperature and humidity data in real time, and is supplemented by the temperature adaptive speed adjustment control algorithm. The PWM modulation signal is output to the L9110 DC motor drive module for driving and adjusting the DC motor speed to achieve the effect of automatically controlling the fan speed. The innovation of this design lies in that this research starts from the traditional fan, and the intelligent control can be realized by adding this design system, taking into account its convenience and comfort.

On developing an automatic control system for the dump conveyor of a wheel excavator

One of the main ways to increase the rotary excavator productivity is to automate excavator operation. The article presents an automatic speed adjustment system for the stacking conveyor belt of a trench rotary excavator. It is shown that the automated control system will allow taking into account the rotor actual rotation speed and the bucket fill factor, processing data and solving tasks of the excavator operation automatic control in excavation mode. The represented automated control system will ensure the conveyor operation with the necessary, but not maximum speed. Therefore, the conveyor will not work “in vain”, that, in its turn, will reduce operating costs including energy.

Simulation of Vector Controlled Adjustable Speed System of Doubly Fed Induction Machine

In this work the performance of vector speed control of doubly fed induction machine is considered. Based on the analysis of doubly fed induction machine dynamic mathematical model and the vector control principle, the construction of the motor control system has been completed. Doubly fed induction machine module, the vector controller module, Clark transform module, Park transform module, inverter module, flux module, speed-conditioning module have been set up by0adopting the idea of modular in MATLAB/SIMULINK environment. Through the organic integration of functional modules, the vector control doubly fed induction machine system has been constituted. Simulation results show the changes in the machine electromagnetic torque, the dynamic changes of speed curve, which demonstrate that the real system can be well simulated with fast dynamic response speed, steady-state small of static error, and strong ability of anti-load disturbance.

Model reference adaptive vector control for induction motor without speed sensor

The wide applications of vector control improve the high-accuracy performance of alternating current (AC) adjustable speed system. In order to obverse the full-order flux and calculate the real-time speed, this article introduces the motor T equivalent circuit to build a full-order flux observer model, where the current and flux variables of stator and rotor are adopted. Model reference adaptive control is introduced to build the AC motor flux observer. The current output is used as feedback to build the feedback matrix. The calculation method of motor speed, which is part of the inputs of flux observation, is applied to realize the adaptive control. The concept of characteristic function is introduced to calculate the flux, of which the foundation is the variables of composite form of voltage and current models. The characteristic function is deduced as a relative-state variable function. The feedback matrix is improved and designed to ensure the motor flux observer is a smooth switch between current and voltage model in low and high speeds, respectively. Experimental results show that the feedback and characteristic model are feasible, and the vector control with speed sensorless based on the full-order flux observer has better performance and anti-disturbance.

小水力発電への可変速システムの適用

小水力発電への可変速システムの適用

Novel Strategy for BLDC Motor Rotor Position Detection

The detection of rotor position plays an important role in the motor speed-adjustment system. By analyzing the back-EMF method and its improved methods, we know the amplitude of back-EMF is too small to be detected when the motor run at low speed. A new detection method of rotor position has been proposed in this paper. It detects the zero crossing point of line terminal voltage difference to acquire the rotor position signal after a 90 degrees mechanical angle delay. The amplitude of line terminal voltage difference is large in wide speed range, so the rotor position signal can be accurately acquired in most situations. Simulation results proved that the new method can obtain the rotor position signal exactly in both high and low speed. It meets the wide speed range of motor.

Simulation Realization of Frequency-Variable and Speed-Adjustable System Based on Vector Control

To provide the necessary design parameters for the actual motor control system, The paper introduces the modeling course of voltage space vector pulse wide modulation (SVPWM) arithmetic and AC motor under MATLAB/SIMULINK environment, discuss founding dynamic model of frequency-variable speed-adjustable system based on vector control, according to the principle of SVPWM. The paper presents the new detailed method of realizing simulation, key problems and results of the simulation were analyzed in detail. The experimental simulation results show that this system has smaller fluctuations of voltage and torque, quicker response speed, and all of the indicators accord with the performance of the actual motor. the simulation arithmetic have value to realize controlling motor with digital signals processing.

Research on Mechanical Dynamics in DC Servo Motor Adjustment System Based on Applied Technology

This article has made the mathematical model and simulation, and provides the reliable theory basis for practical application of speed adjustment, through the research on DC servo motor adjustment system, and analysis of dynamic and static characteristics of Single loop with current positive feedback and voltage negative feedback speed adjustment system.

Integral Sliding Mode Control Based on Exponential Approach Law for Brushless Double Fed Machines

In this paper, based on the principle of exponential approach law, an integral sliding mode controller (ISMC) for brushless doubly-fed machine (BDFM) adjustable speed system is presented. Because of using the integral sliding mode control, the proposed controller for BDFM employs the robustness and excellent dynamic performances of ISMC. Simulation results show that the proposed control strategy is of the feasibility, correctness and effectiveness.

Modeling and Simulation of Voltage Frequency Ratio Control System for Asynchronous Motor

Alternating current (AC) machine speed regulation system plays a very important role in our industrial and agricultural production. This paper focuses on the three-phase asynchronous motor which account for most of the proportion of the AC machines. Firstly, this paper establishes three mathematical models of asynchronous motor based on dq coordinate system and introduces the principle of V/f speed-adjusting for asynchronous motor, and then the paper builds the simulation models of V/f speed-adjusting control system for asynchronous motor based on Matlab/Simulink. The simulation results of the V/f speed-adjusting control system verifies the correctness of the simulation models and the principle of speed regulation.

Modeling and Simulation of Vector Control System for Asynchronous Motor

Alternating current (AC) machine speed-adjusting system plays a very important role in our daily life. Firstly, this paper studies the basic principle of vector control system for three-phase asynchronous motor based on the MT coordinate system, and this paper especially gives the calculation principle diagram of the current model for rotor flux. Then this paper establishes the double closed-loop vector control system based on the Matlab/Simulink detail, and gives the simulation results. The simulation results of the double closed-loop vector control system verify the correctness of the simulation models and the principle of vector controlling.

Research of Vector Control for Asynchronous Motor System Based on MRAS

A new speed-adjustment approach of vector control for asynchronous motor is presented in the paper based on MRAS, It adopts a rotate speed calculating module which is designed specifically replaced Conventional rotate speed detecting system. The approach overcomes some shortcomings that comes from the precision and installation of rotate speed sensor. Motor rotate speed and torque curve are observed under different parameters based on MATLAB, and are analysed statically and dynamically. Simulation result showed touque ripple of this speed-adjustment system is small and timing is smooth, which can satisfy the demand of most electric equipment for speed-adjustment performance. Simulation result can realize asynchronous motor Control effectively.

Belt Conveyor Electromagnetic Speed Adjustment Technology

The objective of this paper is to provide an adjustable-speed for belt conveyor, which is used for low power occasions, reducing equipment investment. We adopt three-phase step motor to drive and electromagnetic speed control technology to regulate speed. The paper introduces structure of electromagnetic speed Adjustment belt conveyor, the working principle of open-loop electromagnetic speed Adjustment system and closed-loop electromagnetic speed Adjustment system, connection mode of electromagnetic speed motor. The paper points out the characteristics and applied situation of the electromagnetic speed belt conveyor, compared with frequency speed control equipment with high cost, it is appropriate to choose electromagnetic speed control technology when the power consumption is small.

Constant Power Speed-Adjusting of Shearer Cutting Motor by Single Neuron Self-Adaptive PID Controlling

In order to suit better for variations of coal and rock with different properties, solve the problem of big fluctuation of a cutting motor power, and ensure the durable high-efficient, high-energetic working of a shearer, a constant power speed-adjusting system of shearer cutting motor is designed based on the theory and the method of single neuron self-adaptive PID controlling, the system effects constant power function of shearer cutting motor by adjusting continually the shearer’s haulage speed. A systematic simulation model is build by using the Matlab/Simulink, and the experiment shows: the speed-adjusting system of single neuron self-adaptive PID controlling has following advantages by comparing it with a traditional controlling method: adjustment time of haulage speed decreases by 0.6s, overshoot and adjustment time of the cutting motor power lower by 2.4% and 0.27s respectively, which improves the working efficiency of the shearer by a rapid reaction speed and a good controlling property.

The APPliCation of Fuzzy Neural Network Control in the AC Speed Adjustment System

This paper investigates the complex controlled object. A method of fuzzy-network is proposed. Results of simulation research show that the controller has not only high self-study ability, but also high robustness, and let the performance in AC speed adjustment system quickly improve.

Double Closed-Loop Motor Modeling and Analysis for Lunar Rover Simulation

Motor drive control is the major study field in the development of lunar rover. Based on the double-closed DC loop adjustable-speed system, a motor drive simulation module using a position recursive PID control algorithm is developed, which is integrated into the multi-body dynamics simulation system, to carry out the whole lunar rover simulation. And the cruise process of lunar rover locomotion in the complex lunar terrain is simulated in a virtual environment.