港口装卸设备单机多电控系统的整合研究及应用

随着港口装卸设备的自动化和复杂程度提高,设备的电控系统种类和样式呈现多元化的趋势。由于设备主电控系统与各子系统品牌的差异,对于设备备件、维修一体化的管理造成困难。通过对设备电控系统进行一体化升级和改造研究,将主系统与子系统进行整合,能够有效解决备件管理、技术管理、成本管控中存在的难题,在设备管理工作中具有一定的借鉴意义。

多个电控板固件的在线升级方案设计与应用

为具有多个电控板的家电设备设计了一种固件在线升级方案,通过一定时间间隔轮询的方式逐个对可以升级的电控进行升级,针对空调内部不同作用的电控板,采用单分区或带有备份区域的双分区OTA升级方案,同时设计了在升级过程中防变砖的处理措施以提升整体的可靠性。该方案不仅能确保固件正确高效地升级成功,还可以确保在升级过程中出现异常情况时能自动恢复原固件,从而不影响设备的运行。方案控制逻辑简单易实现,具有较高的可靠性及良好的用户体验。

Multi-mode controller IC for soft-switched flyback converter with high efficiency over the entire load range

This paper presents a multi-mode control scheme for a soft-switched flyback converter to achieve high efficiency and excellent load regulation over the entire load range. At heavy load, critical conduction mode with valley switching (CCMVS) is employed to realize soft switching so as to reduce turn-on loss of power switch as well as conducted electromagnetic interference (EMI). At light load, the converter operates in discontinuous conduction mode (DCM) with valley switching and adaptive off-time control (AOT) to limit the switching frequency range and maintain load regulation. At extremely light load or in standby mode, burst mode operation is adopted to provide low power consumption through reducing both switching frequency and static power dissipation of the controller. The multi-mode control is implemented by an oscillator whose pulse duration is adjusted by output feedback. An accurate valley switching control circuit guarantees the minimum turn-on voltage drop of power switch. The pro-totype of the controller IC was fabricated in a 1.5-μm BiCMOS process and applied to a 310 V/20 V, 90 W flyback DC/DC converter circuitry. Experimental results showed that all expected functions were realized successfully. The flyback converter achieved a high efficiency of over 80% from full load down to 2.5 W, with the maximum reaching 88.8%, while the total power consumption in standby mode was about 300 mW.

Researches On The Design And Application Of DSP Multi- motor Collaborative Control System

As an important branch in the field of servo control, multi-motor coordination motion control applications are increasingly widespread.For open CNC system requirement, taking DSP as master core, combing with specific integrated stepper motor driver chip LMDI8201T, this designed a serial communication-based new collaborative multi-motor control system, which has characters of highly integrated, good stability, real-time, convenient man-machine interface.The test results show that the system fully meet performance requirements and achieved the motion control functions.

Design of hybrid damping controller based on multi-target gravitational search optimization algorithm in a multi-machine power system with high penetration of PV park

A mathematical approach was proposed to investigate the impact of high penetration of large-scale photovoltaic park(LPP) on small-signal stability of a power network and design of hybrid controller for these units.A systematic procedure was performed to obtain the complete model of a multi-machine power network including LPP.For damping of oscillations focusing on inter-area oscillatory modes,a hybrid controller for LPP was proposed.The performance of the suggested controller was tested using a 16-machine 5-area network.The results indicate that the proposed hybrid controller for LPP provides sufficient damping to the low-frequency modes of power system for a wide range of operating conditions.The method presented in this work effectively indentifies the impact of increased PV penetration and its controller on dynamic performance of multi-machine power network containing LPP.Simulation results demonstrate that the model presented can be used in designing of essential controllers for LPP.

CYLINDER-SPHERE 3-DOF ULTRASONIC MOTOR AND ITS CONTROL

A three degree-of-freedom (DOF) ultrasonic motor (USM) with a cylinder-shaped stator and a spherical rotor is introduced, which uses one first order longitudinal and two second order bending nature vibration modes of the cylinder. Control strategies for the two DOF trajectory following are studied and applied to the prototype USM. Vibration amplitude control is employed for speed regulation. The first trajectory following strategy is a step-by-step interpolation. The second strategy is vector decomposition control. Three pulse width modulation (PWM) methods for the exciting voltage regulation are investigated. These methods are compared and verified by several experiments. The key is to keep the phase differences of the three vibration constants and small exciting voltage distortion while the exciting voltages are changed for simplifing the control process and obtaining good control performance. The vector control method has advantages of small trajectory following error, smooth moving and low noise.

The Modified Multiple Model Switching Tuning Control Application in AVC

In the complex mechanical vibration environment, the dominant frequency of the system varies remarkably and swiftly under various running conditions, which also characterizes uncertainty and time-variation. It is very impending and important to suppress or isolate the detrimental vibrations related to the above memtoned system with active vibration control (AVC) technology. This paper presented the improved linear quadratic gaussian (LQG) control scheme with a specified filter to realize broadband disturbance/noise attenuation and assure intensive suppression of vibration at the key vibration frequency, then applies and modifies the multiple model switching tuning (MMST) control method by disturbance observation to track the variation of dominant vibration component timely. The effectiveness and superiority of the presented control method were demonstrated by numerical simulation and AVC experiment on a flexible cantilever beam under sweeping excitation.

Effects of Temperature Gradient and Cooling Rate on the Formation of Methane Hydrates in Coarse Sand

Temperature gradient and cooling rate have an obvious effect on formation of methane hydrate. The process for formation of methane hydrate in coarse sand is monitored to tmderstand the relationship between temperature gradient and cooling rate and nucleation, growth and distribution of methane hydrate by using the electrical resistivity method. The results show that the change of resistivity can better reflect the nucleation and growth and distribution of methane hydrate. Temperature gradient promotes the nucleation, formation, and formation rate of methane hydrate. At a temperature gradient of 0.11℃/cm, the rate of methane hydrate formation and saturation reaches a maximum. Cooling rate has little effect on the methane hydrate formation process. Judging from the outcome of final spatial distribution of methane hydrate, the cooling rate has an obvious but irregular effect in coarse sand. The effect of tempera^re gradient on distribution of methane hydrate in coarse sand is less than that of cooling rate. At a temperature gradient of 0.07℃/cm, methane hydrate is distributed uniformly in the sample. If the temperature gradient is higher or lower than this value, the hydrate is enriched in the upper layer of sample.

Vector Control Scheme of Five-Phase Induction Machines under Open-Circuit Phase Faults

Multiphase induction machine is normally controlled using rotor field oriented vector control. Under phase（s） loss, the machine currents can be optimally controlled to satisfy certain optimization criteria. In this paper, a vector control scheme to a five-phase induction machine is introduced to ensure equal phase currents and minimum torque ripples under a phase open circuit. The controller idea can be extended to any number of phases with any number of open phases. The fundamental dq components of the stator voltage are obtained using only two PI controllers for the fundamental sequence plane, as in conventional vector control of three-phase machines. Based on steady state model, a simple expression is derived to estimate the required dq voltage components of other sequence planes to ensure equal stator phase currents and minimum torque ripple. A five-phase machine is simulated using MATLAB/Simulink to ensure controller validity.

FULMS algorithm based multi channel active vibration control of piezoelectric flexible beam

A multi-channel active vibration controller based on a filtered-u least mean square （FULMS） control algorithm is analyzed and implemented to solve the problem that the vibration feedback may affect the measuring of the reference signal of the filtered-x least mean square （FXLMS） algorithm in the field of active vibration control. By analyzing the multi-channel FULMS algorithm, the multi-channel controller structure diagram is given, while by analyzing multi-channel FXLMS algorithm and its algorithmic procedure, the control channel model identification strategy is given. This paper also provides an easy but practical way to configure the actuators based on the maximal modal force rule. Taking the configured piezoelectric beam as the research object, an active vibration control experimental platform is established to verify the effectiveness of the identification strategy as well as the FULMS control scheme. Simulation and actual control experiments are done after the model parameters are obtained. Both the simulation and actual experiment results show that the designed multi-channel vibration controller has a good control performance with low order model and rapid convergence.

Integrated Multi-channel High Accuracy Current Control LED Driver with Low Dropout Regulator

This research describes an integrated multi-channel high accuracy current control LED （light emitting diode） driver with low dropout regulator implemented in a 0.35μm TSMC 2P4M CMOS process. With the new trend of backlighting applications for mobile electronics and portable devices requiring a smaller size, lower cost, lesser noise and accurate current control LED driver, it came up with the idea of integrating more than one design features within a single chip. The analysis of using a capacitor-less low dropout regulator to power the constant current source has been explored, with the implementation of wide range battery voltage of 3 V to 5 V. Possible load current variations were introduced and verified to output a fixed voltage of 2.8 V. A regulated cascode current mirror structure forms the multi-channel configuration string of LED＇s; the design ensures a current matching of less than 1% error and achieves a high accuracy current control of less than 1% error, regardless of the LED＇s forward voltage variation. Moreover, for high end portable device with multimedia applications, dimming frequency can be set to 10 MHz. In addition, a switching output is a better approach for managing LED＇s contrast and brightness adjustment as well as maximizing power consumption, ensuring longer life for driving string of LEDs.

Effect of electroacupuncture on egg quality and tumor necrosis factor-a of patients with polycystic ovarian syndrome

Objective To observe the effect of electroacupuncture （EA） on egg quality of polycystic ovarian syndrome （PCOS） patients, and to explore its mechanism. Methods Two hundred patients who received in vitro fertilization-embryo transfer （IVF-ET） were divided into an EA group （102 cases） and a control group （98 cases） according to random number table. All the patients in the two groups were given Diane-35 and gonadotropin-releasing hormone agonist （GnRH-α） for ovarian hyperstimulation. Besides, EA intervention was applied to Shenshu （肾俞 BL 23）, Qihai （气海 GV 6）, Zusanli （足三里ST 36）, Sanyinjiao （三阴交 SP 6）, Neiguan （内关 PC 6） and Zigong （子宫 EX-CA1）, etc. in the EA group. Then egg quality, final outcome of pregnancy and levels of tumor necrosis factor-α （TNF-α） were compared between the two groups. Results （1） EA intervention significantly improved high quality embryo rate of PCOS patients （P〈0.05）, and clinical pregnancy rate was increased by 8.36%; （2） EA intervention significantly reduced the TNF-α levels of follicular fluid （13.61±15.46 vs 34.09±93.53, P〈0.05）; （3） TNF-α levels of serum and follicular fluid in the pregnancy group were lower than those of non-pregnancy group [pregnancy group： （53.91±63.32） pg/mL, （14.93±25.37） pg/mL, nonpregnancy group： （76.82 ± 82.96） pg/mL, （25.04 ± 35.79） pg/mL], and the differences were significant （both P〈0.05）. Conclusion EA improves egg quality of PCOS patients and increases the clinical pregnancy rate of IVF-ET, the mechanism may be related to TNF-α levels.

Wide-area nonlinear robust voltage control strategy for multi-machine power systems

This paper presented a novel wide-area nonlinear excitation control strategy for multi-machine power systems. A simple and effective model transformation method was proposed for the system's mathematical model in the COI (center of inertia) coordinate system. The system was transformed to an uncertain linear one where deviation of generator terminal voltage became one of the new state variables. Then a wide-area nonlinear robust voltage controller was designed utilizing a LMI (linear matrix inequality) based robust control theory. The proposed controller does not rely on any preselected system operating point, adapts to variations of network parameters and system operation conditions, and assures regulation accuracy of generator terminal voltages. Neither rotor angle nor any variable's differentiation needs to be measured for the proposed controller, and only terminal voltages, rotor speeds, active and reactive power outputs of generators are required. In addition, the proposed controller not only takes into account time delays of remote signals, but also eliminates the effect of wide-area information's incompleteness when not all generators are equipped with PMU (phase measurement unit). Detailed tests were conducted by PSCAD/EMTDC for a three-machine and four-machine power systems respectively, and simulation results illustrate high performance of the proposed controller.

Multi-level multi-area hybrid automatic voltage control system and its trial operation in Northeast China Grid

In order to coordinate automatic voltage control （AVC） systems of a large interconnected system, a multi-level multi-area hybrid automatic voltage control （MLMA-HAVC） system was constructed. This system began its trial operation in the Northeast China Grid in January 2010, and for the first time in China and abroad it realized automatic close-loop control of multi-area and multi-level interconnected power grid and multi-objective self-approaching optimization in aspects of security, high quality and economic operation. This system has three breakthroughs in theory and engineering application： l） Established the MLMA-HAVC theory to solve multi-objective optimization of large-scale system; 2） proposed reactive power/voltage coordination control method to inhibit or further eliminate regional oscillations; 3） presented advanced state estimation algorithm to guarantee acquisition of high reliability data. This paper summarizes the basic principle of MLMA-HAVC, and reports engineering realization of MI ,MA-HAVC system in tha Northeast China Grid.

Photovoltaic properties of ferroelectric solar cells based on polycrystalline BiFeO_3 films sputtered on indium tin oxide substrates

To study the ferroelectric photovoltaic effect based on polycrystalline films, preparation of high-quality polycrystalline films with low leakage and high remnant polarization is essential. Polycrystalline BiFeO3 （BFO） thin films with extremely large remnant polarization （2Pr = 180 ~aC/cm2） were successfully deposited on glass substrates coated with indium tin oxide using a modified radio frequency magnetron sputtering method. Symmetric and asymmetric cells were constructed to investigate the ferroelectric photovoltaic effect in order to understand the relationship between polarization and photovoltaic response. All examined cells showed polarization-induced photovoltaic effect. Our findings also showed that the ferroelectric photovoltaic effect is highly dependent on the material used for the top electrode and the thickness of the polycrystalline film.

A new power coordination method for islanded micro-grid basing on multi-agent system

Multi-agent system (MAS) can provide flexible and intelligent control for micro-grid (MG). In this paper, a new power coordination method of MAS is presented for MG. New way for dispatching controllable generations (CGs) and direct cooperation between storages and CGs are designed. Real-time emulations of the coordination, including the usage of both CGs and storages, have been carried out in islanded situation basing on this method, and much higher performance than conventional method is found.

A new strategy to improve the sensitivity and selectivity of dopamine detection

We applied the combination of in situ electrochemical liquid-phase microextraction and square-wave voltammetric stripping analysis for the first time as a highly sensitive and selective approach for the detection of dopamine. A mixed gel of graphene sheets and an ionic liquid of 1-octyl-3-methylimidazolium hexaflurophosphate(OMim PF6) was used as a micro liquid-phase to pre-concentrate dopamine by controlled potential electrolysis from an aqueous solution(as a donor phase), followed by square-wave voltammetric stripping detection. Under optimized conditions, a linear calibration curve was obtained in the range of 0.05 to 1.0 ?mol/L in the presence of excess ascorbic acid and uric acid. The detection limit has been found to be 8.0 nmol/L(S/N=3).