双锅交替式真空油炸机控制系统的设计

阐述了以 80 31单片机为核心、PC机作监控的双锅交替式真空油炸机控制系统 ,详细介绍了软硬件的具体设计过程。

Predictive current control system of PMSM based on LADRC

For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting in the inability to balance the system robustness and dynamic performance.A PMSM optimal control strategy combining linear active disturbance rejection control(LADRC)and two-vector MPCC(TV-MPCC)is proposed.Firstly,a mathematical model of a PMSM is presented,and the PMSM TV-MPCC model is developed in the synchronous rotation coordinate system.Secondly,a first-order LADRC controller composed of a linear extended state observer and linear state error feedback is designed to reduce the complexity of parameter tuning while linearly simplifying the traditional active disturbance rejection control(ADRC)structure.Finally,the conventional PI speed regulator in the motor speed control system is replaced by the designed LADRC controller.The simulation results show that the speed control system using LADRC can effectively deal with the changes in motor parameters and has better robustness and dynamic performance than PI control and similar methods.The system has a fast motor speed response,small overshoot,strong anti-interference,and no steady-state error,and the total harmonic distortion is reduced.

Strengthening pelletization of manganese ore fines containing high combined water by high pressure roll grinding and optimized temperature elevation system

Pelletization is one of useful processes for the agglomeration of iron ore or concentrates. However, manganese ore fines are mainly agglomerated by sintering due to its high combined water which adversely affects the roasting performance of pellets. In this work, high pressure roll grinding(HPRG) process and optimization of temperature elevation system were investigated to improve the strength of fired manganese ore pellets. It is shown that the manganese ore possesses good ballability after being pretreated by HPRG twice, and good green balls were produced under the conditions of blending 2.0% bentonite in the feed, balling for 7 min at 16.00% moisture. High quality roasted pellets with the compressive strength of 2711 N per pellet were manufactured through preheating at 1050 °C for 10 min and firing at 1335 °C for 15 min by controlling the cracks formation. The fired manganese pellets keep the strength by the solid interconnection of recrystallized pyrolusite grains and the binding of manganite liquid phase which filled the pores and clearance among minerals. The product pellets contain high Mn grade and low impurities, and can be used to smelt ferromanganese, which provides a possible way to use imported manganese ore fines containing high combined water to produce high value ferromanganese.

A Control Algorithm Derived from Immune Principle

Artificial immune systems (AIS) are biologically inspired problem solvers having been successfully applied in many fields. A controller was designed according to the interactive mechanism between immune molecules. Multiform antigens were constructed and corresponding antibodies designed. The concept of “antibiotic” is presented, whose features and injection time as well as construction method discussed. Based on biological immune mechanism, some fuzzy rules are summarized and used in constructing the controller. The result shows that this controller is simple in structure and can be easily computed, so it is suitable for real time control. The control variable can change adaptively according to the error and its change tendency. Therefore the controller is very flexible and can be directly used in controlling some nonlinear plants. To test the validity of the algorithm, two simulation examples are given, one is linear, and the other is nonlinear. The Simulation results indicate that the control performance of this algorithm is better than that of the conventional PID.

Disturbance rejection control for Raymond mill grinding system based on disturbance observer

In the Raymond mill grinding processes,high-accuracy control for the current of Raymond mill is vital to enhance the product quality and production efficiency as well as cut down the consumption of spare parts.However,strong external disturbances,such as variations of ore hardness and ore size,always exist.It is not easy to make the current of Raymond mill constant due to these strong disturbances.Several control strategies have been proposed to control the grinding processes.However,most of them(such as PID and MPC)reject disturbances merely through feedback regulation and do not deal with the disturbances directly,which may lead to poor control performance when strong disturbances occur.To improve disturbance rejection performance,a control scheme based on PI and disturbance observer is proposed in this work.The scheme combines a feedforward compensation part based on disturbance observer and a feedback regulation part using PI.The test results illustrate that the proposed method can obtain remarkable superiority in disturbance rejection compared with PI method in the Raymond mill grinding processes.

Directional Overcurrent Relays Coordination Restoration by Reducing Minimum Fault Current Limiter Impedance

FCL （fault current limiter） is used to solve relays miscoordination problem arises from DG （distributed generation） installation. In most published researches, different optimization methods are developed to obtain optimal relay settings to achieve coordination in case of not installing DG, then depending on the achieved optimal obtained relay settings, FCL impedance is deduced to ensure relays coordination restoration in case of installing DG. Based on original optimal relay settings, obtained FCL impedance is not the minimum one required to achieve relay coordination. The contribution of this paper is the generation of multi sets of original relay settings that increase the possibility of finding FCL impedance of minimum value which is lower than the calculated value based on original optimal relay settings. The proposed method achieves better economic target by reducing FCL impedance. The proposed approach is implemented and tested on IEEE-39 bus test system.

Effects of Traditional Ecological Knowledge on the Droughtresistant Mechanisms of the Hani Rice Terraces System

The Hani Rice Terraces System is one of the Globally Important Agricultural Heritage Systems（GIAHS） sites which can successfully resist extreme droughts.The reason is not only that the forests and terraces have the important function of water conservation,which provide and conserve adequate water resources for this complex ecosystem,but also that Hani traditional ecological knowledge plays an important role in the drought-resistance process.In this paper,drought-resistant mechanisms of the Hani Rice Terraces System have been analyzed first,then Hani traditional ecological knowledge has been analyzed based on a comprehensive literature review,a questionnaire survey and key informant interviews.The results show that the Hani nationality has developed knowledge of water management techniques,including water conserving construction,water allocation and ditch management.The Hani people are also highly conscious of water resources protection.There is a good deal of forest resource management knowledge and worship of forests,which have effectively helped in protecting the forest ecological system.In the reclamation and maintenance of Hani terraced fields,the Hani people have developed a series of farming systems,which have effectively protected the terrace ecosystem.Through analyzing this knowledge of water management,forest resource management and Hani terraced fields management,our paper confirms the important role that traditional ecological knowledge plays in maintaining stability of the system and realizing the efficient use of water resource.This is not only helpful for preserving cultural heritage,but is vital for protecting the Hani Rice Terraces System as a whole.

Active Control of Fan Noise

In the wake-rotor interaction fan noise, a number of the interacting modes at the blade passing frequency （BPF） and its harmonics are generated which are prescribed by the number of stator and rotor blades etc. In the present study, the dominant mode is tried to be suppressed by the secondary sound from the loudspeaker actuators. One of the novel features of the present system is the adoption of the control board with the Field Programmable Gate Array （FP（3A） hardware and the LabVIEW software to synchronize the circumferentially installed loudspeaker actuators with the relative location of rotational blades under arbitrary fan rotational speeds. The experiments were conducted under the conditions of three rotational speeds of 2004, 3150, and 4002 [rpm]. The reduction in the sound pressure level （SPL） was observed for all three rotational speeds. The sound pressure level at the BPF was reduced approximately 13 [dB] for 2004 [rpm] case, but not so large reduction was attained for other cases probably due to the inefficiency of the loudspeaker actuators at high frequencies