Design of speed controller for electronic fuel injection gasoline generator based on feed-forward PID control

As for the application of electronic fuel injection （EFI） system to small gasoline generator set, mechanical speed controller cannot be coupled with EFI system and has the shortcomings of lagged regulation and poor accuracy, a feed-forward control strategy based on load combined with proportional-integral-differential （PID） control strategy was proposed, and a digital speed controller applied to the electrical control system was designed. The detailed control strategy of the controller was intro- duced. The hardware design for the controller and the key circuits of motor driving, current sampling and angular signal captu- ring were given, and software architecture was discussed. Combined with a gasoline generator set mounted with EFI system, the controller parameters were tuned and optimized empirically by hardware in loop and bench test methods. Test results show that the speed deviation of generator set is low and the control system is stable in steady state; In transient state the control system responses quickly, has high stability under mutation loads especially when suddenly apply and remove 100% load, the speed deviation is within 8% of reference speed and the transient time is less than 5 s, satisfying the ISO standard.

Real-time Feed-forward Force Compensation for Active Magnetic Bearings System Based on H∞ Controller

There are two kinds of unbalance vibrations—force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings（AMB） system. And two unbalance compensation methods—closed-loop feedback and open loop feed-forward are presented to reduce the force vibration. The transfer function order of the control system directly influencing the system stability will be increased when the closed-loop method is adopted, which makes the real-time compensation not easily achieved. While the open loop method would not increase the primary transfer function order, it provides conditions for real-time compensation. But the real-time compensation signals are not easy to be obtained in the open loop method. To implement real-time force compensation, a new method is proposed to reduce the force vibration caused by the rotor unbalance on the basis of AMB active control. The method realizes real-time and on-line force auto-compensation based on H∞ controller and one novel feed-forward compensation controller, which makes the rotor rotate around its inertia axis. The time-variable feed-forward compensatory signal is provided by a modified adaptive variable step-size least mean square（VSLMS） algorithm. And the relevant least mean square（LMS） algorithm parameters are used to solve the H∞ controller weighting functions. The simulation of the new method to compensate some frequency-variable and sinusoidal signals is completed by MATLAB programming, and real-time compensation is implemented in the actual AMB experimental system. The simulation and experiment results show that the compensation scheme can improve the robust stability and the anti-interference ability of the whole AMB system by using H∞ controller to achieve close-loop control, and then real-time force unbalance compensation is implemented. The proposed research provides a new control strategy containing real-time algorithm and H∞ controller for the force compensation of AMB system. And the stability of the control system is finally improved.

Load Shedding Strategy Based on Combined Feed-Forward Plus Feedback Control over Data Streams

In data stream management systems (DSMSs), how to maintain the quality of queries is a difficult problem because both the processing cost and data arrival rates are highly unpredictable. When the system is overloaded, quality degrades significantly and thus load shedding becomes necessary. Unlike processing overloading in the general way which is only by a feedback control (FB) loop to obtain a good and stable performance over data streams, a feedback plus feed-forward control (FFC) strategy is introduced in DSMSs, which have a good quality of service (QoS) in the aspects of miss ratio and processing delay. In this paper, a quality adaptation framework is proposed, in which the control-theory-based techniques are leveraged to adjust the application behavior with the considerations of the current system status. Compared to previous solutions, the FFC strategy achieves a good quality with a waste of fewer resources.

Feed-Forward-Like Decoupling Control in Coagulation Bath of Carbon Fiber Precursor

The coagulation bath system of carbon fiber precursor is a complicated and multivariable coupling system. Based on the model of industrial production,the full dynamic decoupling control of the coagulation bath system of carbon fiber precursor is achieved in combination with multivariable feed-forward-like decoupling and proportional-integral-differential( PID) control. Compared with the conventional PID decoupling control,the experiment results show that the proposed method has a better control effect. The use of the controller can achieve complete decoupling of three parameters from coagulation bath system. The method should have great applications.

Study of control strategy and simulation in anoxic-oxic nitrogen removal process

The control strategy and simulation of external carbon addition were specially studied in an anoxic-oxic(A/O) process with low carbon: nitrogen(C/N) domestic wastewater. The control strategy aimed to adjust the flow rate of external carbon dosage to the anoxic zone, thus the concentration of nitrate plus nitrite(NOx--N) in the anoxic zone was kept closed to the set point. The relationship was studied between the NOx--N concentration in the anoxic zone(S_ NO) and the dosage of external carbon, and the results showed that the removal efficiency of the total nitrogen(TN) could not be largely improved by double dosage of carbon source when S_ NO reached about 2 mg/L. Through keeping S_ NO at the level of about 2 mg/L, the demand of effluent quality could be met and the carbon dosage could be optimized. Based on the Activated Sludge Model No.1(ASM No.1), a simplified mathematical model of external carbon dosage was developed. Simulation results showed that PI controller and feed-forward PI controller both had good dynamic response and steady precision. And feed-forward PI controller had better control effects due to its consideration of influent disturbances.

三轴电磁-压电混合驱动快速刀具伺服的轨迹跟踪控制

三轴快速刀具伺服(Fast Tool Servo,FTS)具有更高的刀具空间运动柔性,逐渐用于复杂光学曲面和微纳结构表面的切削加工。针对所研制电磁-压电混合驱动三轴FTS存在的轴间耦合、高频谐振和迟滞非线性等因素对轨迹跟踪性能的影响,研究综合补偿策略实现三轴空间轨迹的高性能跟踪控制。以陷波滤波器抑制系统高频谐振,以前馈解耦补偿弱化平面轴间耦合;针对法应力电磁驱动和压电驱动的迟滞非线性,提出以线性动力学模型级联Prandtl-Ishlinskii模型描述各轴的动态迟滞特性,并构建无需直接求逆的迟滞前馈补偿模型,实现系统的迟滞非线性补偿。谐波扫频测试结果表明:所采用的陷波滤波器可以很好地消除高频谐振,前馈解耦补偿可将平面XY轴间的耦合幅值降低约14 dB。宽频域内迟滞建模结果表明:平面XY轴和Z轴的动态迟滞建模误差分别小于±2.2%和±1.8%。以PID为主控制器,对宽频谐波(10~100 Hz)的跟踪结果表明:采用综合补偿策略获得各轴的最大跟踪误差约为仅采用逆动力学前馈补偿的25%~50%,进一步对空间螺旋球面轨迹进行了跟踪测试,证明了所构建的综合补偿控制策略的有效性。

Stabilization control of a bumblebee in hovering and forward flight

Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stability （passive stability）. But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization control of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds considered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizontal velocities, pitching rate and pitch angle （which can be measured by the sensory system of the insect）, to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable.

Study of the control-equilibrium of control systems

Not so much had been talked about equilibrium in control area. On the basis of the phenomenon of balance, the concept of control-equilibrium and control-equilibrium of a control system is proposed. According to this theory, a perfect control method should not only guarantee stability of the system, but also ensure the control-equilibrium of the system. To achieve the control-equilibrium, feed-forward control is required.

Ultra-Modified Control Algorithms for Matrix Converter in Wind Energy System

This paper proposes an ultra-modified SSA(symmetric sequence algorithm)of space vector modulation of MC(matrix converter).The ultra-modified technique improves the drawbacks of the modified one where it provides a reduction of the total harmonic distortion for both output voltage and current.Also this paper proposes a modified feed forward controller of the MC with indirect space vector modulation.The modified feed forward provides a solution for the change in the output voltage due to change in wind speed,where it provides a constant output voltage with constant frequency even if the wind speed changed.Some of the advantages of MC are introduced in this paper.These advantages represented in the output frequency of MC which may be greater than the input frequency,controlling rms value of the output voltage and the ability to control the IDF(input displacement factor).At the end of this paper simulation and experimental results are introduced which give a precise proof to the proposed algorithms.

基于组态王软件的流量-液位前馈反馈控制方法研究与实现

文章从工程实践出发,设计了一个基于组态王的水箱液位前馈反馈控制系统。系统体现出扰动不被控量影响的前馈作用优势,同时克服多个扰动影响,降低系统对前馈补偿器的需求,在实际工程操作过程中能够得以实现。结合组态王中的开发组态界面,定义相应的变量和设备,实现动画连接等可视化界面的优点,采用MATLAB版本(2021b)对系统控制作用进行仿真,实现对水箱液位的监控。实验结果表明,该控制系统操作界面结构设计合理、易于操作,具有良好的行业应用前景。

无线电能传输系统最大效率追踪及恒压输出复合控制方法

针对无线电能传输(WPT)系统的传输效率受耦合线圈之间的互感以及负载影响的特点,该文提出一种基于阻抗匹配技术的最大效率追踪及基于前馈PI控制的恒压输出复合控制方法。首先,对双边LCC型WPT系统的参数和传输效率进行分析,通过调整系统参数优化系统的传输效率。其次,在二次侧使用DC-DC变换器采用阻抗匹配的方法实现最大效率追踪,同时在一次侧采用DC-DC变换器利用前馈PI控制器闭环控制负载端电压实现恒压输出。该方法中,效率追踪和电压控制之间相互独立,互不干扰。此外,该方法还通过系统工作时的电路参数来估算线圈间的互感值,并通过线性拟合的方法对该估算互感值进行修正,得到更精确的互感估算值。最后,通过搭建实验平台验证了该方法的可行性和有效性。与PI控制相比,前馈PI控制方法在快速性和抗扰动性上均具有明显优势。

双闭环控制的三相电压型PWM整流器的研究

针对传统的不控整流电路中网侧电流谐波很大、晶闸管相控整流电路中深控时网侧功率因数低和闭环控制时动态响应慢等问题,设计出一种引入脉冲宽度调制技术的三相电压型整流器。在完成三相电压型整流器的电压外环电流内环的双闭环控制系统设计的基础上,对其进行了仿真实验。仿真结果表明,与不控或相控整流电路相比,该三相电压型PWM整流电路中,不仅输入电流的谐波大大减小,电能可双向流动,能够实现整流和逆变状态下的单位功率因数运行,还可较好地抑制负载突变时直流侧电压的波动,从而显著提高系统的抗扰能力,真正实现绿色环保和高效节能的高度结合。

单相级联H桥整流器平方电压反馈控制算法

以单相级联H桥整流器为研究对象,对其控制策略进行了研究。首先在采用双闭环控制策略的基础上,构建了dq前馈解耦模型,并通过二阶广义积分算法改善了虚拟交流分量对系统的影响,实现了网侧电流对电压相位、频率的快速精确追踪。其次,对传统电压平衡控制算法进行了改进,通过对功率平衡关系的定义,将输出电压平方作为控制信号,增强了系统自适应能力,提高了系统在投切载时的动态性能。最后,基于MATLAB/Simulink软件进行仿真,验证了所提策略的正确性和有效性。

基于滤波x-LMS算法的磁悬浮隔振器控制研究

针对自行研制的磁悬浮隔振器进行自适应前馈控制,设计了基于滤波x最小均方(Filtered x Least Mean Square——滤波x-LMS)算法的控制律。为了将滤波x-LMS算法应用于带有非线性特性的磁悬浮隔振系统,对滤波x-LMS算法进行了改进。在磁悬浮隔振系统上进行振动主动控制实验,实验结果表明,该控制算法取得了良好的减振效果。

提高VSC-HVDC系统供电无源网络的传输容量的控制方法

根据电压源换流器的高压直流输电(VSC-HVDC)系统整流站和逆变站的外部伏安特性,建立VSC-HVDC系统的直流网络等效电路,进而推导出VSC-HVDC系统的小信号模型,通过小信号稳定性分析,获得了VSC-HVDC供电无源网络的传输容量与直流电压、直流侧电容和线路参数之间的关系。并在整流站引入前馈控制以等效增大线路电阻,从而提高系统传输容量。最后,利用PSCAD/EMTDC软件进行了仿真验证,仿真结果表明,在基于电压源换流器的高压直流输电中,直流电压、直流电容值及直流输电线路的阻抗均会对VSC-HVDC供电无源网络的传输容量产生影响,通过引入前馈控制可大幅提高系统的传输容量。

电网电压不对称对D-STATCOM的影响分析及抑制

分析了电网电压不对称对配电网静止同步补偿器(D-STATCOM)电压输出性能的影响,指出电网电压不对称将导致D-STATCOM直流侧电容电压出现2倍频波动,使得交流输出电压出现负序和三次谐波,严重影响D-STATCOM输出性能,并且由此产生的负序和3次谐波电流将造成装置过流。针对此问题,提出一种改进开关函数调制法,抑制了3次谐波电流,改善了D-STATCOM的电压输出性能。提出一种负序电压前馈控制的不对称控制策略,抑制了D-STATCOM因负序电压分量造成的过流,保障了装置的安全可靠运行。仿真实验结果表明,本文提出的方法是行之有效的。

HL-2A装置ECRH主高压电源的研制

介绍了HL-2A装置电子回旋系统主高压电源的研制。用星点控制技术实现了高压直流平台输出电压的调节;用TM-703FB大功率调制管为核心的高压调制技术实现了高压电源输出电压的快速升降及电源的快速保护。用前馈补偿和反馈控制技术实现了输出电压波纹小于1%。电源输出总体指标为?60kV/(25A×4)/1s,满足了ECRH系统的要求。

滑移转向无人车轨迹跟踪控制策略研究

针对滑移转向车辆构型的无人车,通过建立车辆动力学和运动学模型,对LQR(linear quadratic regulator)最优控制算法进行改进,在速度环采用一种自抗滑移的前馈控制,设计了一种轨迹跟踪控制策略。前馈控制有效提高了横摆角速度响应速度,可进一步优化LQR估计器的参数矩阵,保证车辆在提高轨迹跟踪控制精度的同时不影响跟随稳定性。采用Trucksim与Simulink联合仿真进行验证,结果表明:在双移线测试工况下,使用该控制策略的无人车最大横向误差比在双PID控制下小0.086 m,误差收敛速度2.1 s,稳态误差振荡幅值比滑模控制小约0.05 m;不同车速和不同附着系数路面下,无人车最大横向误差浮动小于0.02 m,误差收敛速度不变,设计算法控制效果稳定,验证了其鲁棒性。

基于PSO-RBF神经网络模型的原水水质评价方法及应用

针对自来水生产过程的原水水质评价问题,提出了一种基于PSO-RBF神经网络模型的原水水质评价方法.首先,根据水厂生产经验和历史数据分析,制定面向自来水生产过程的原水水质评价标准.然后,采用粒子群优化(PSO)算法训练的RBF神经网络模型,对苏州市相城水厂的进厂原水水质实施在线评价.最后,将进厂原水水质在线评价结果作为前馈量,增加相城水厂药剂(矾和臭氧)投加过程的前馈控制环节,使得药剂投加量能够根据原水水质的变化及时做出调整.实际应用效果表明,与改进前的反馈控制过程相比,过程出水水质更加平稳,提高了自来水生产过程应对原水水质变化的能力.

南水北调中线渠首前馈控制方案快速计算分析

明渠调水工程中为适时适量的满足下游用水需求,需要提前制定控制方案。前馈控制方案的设计往往较为复杂,且影响因素众多,调度人员难以快速做出决策。基于蓄量补偿法对南水北调中线工程刁河节制闸至十二里河节制闸段作前馈控制,基于蓄量补偿计算结果,分析了初始流量、分水流量与前馈控制时间的关系,构建了单、双变量的前馈控制时间快速计算公式。探究了不同因素对蓄量补偿控制下游水位偏差的影响,得到初始流量、分水流量与下游水位最大偏差之间的函数关系式。针对工程运行中的极端工况,原蓄量补偿控制的下游水位偏差过大的问题,采用二次蓄量补偿规则对渠池进行前馈控制,有效减小了下游水位偏差。