A Novel Feedforward Compensation Canceling Input Filter-Regulator I nteraction

The interaction between the input filter and the control loop of switching regulators often results in detrimental effects, such as loop instability, degradation of transient response, and audiosusceptibility, etc. The concept of pole-zero cancellation is employed to mitigate some of these detrimental effects and is implemented using a novel feedforward loop, in addition to existing feedback loops of a buck regulator. Experimental results are presented which show excellent correlation with theory.     

Input-Filter Design for Switching Regulators

The interaction between the input filter and the control loop of switching regulators often results in detrimental effects, such as loop instability, transient response, and audio-signal-rejection rate, etc. A small-signal average model is derived to investigate these effects. Design constraints of an input-filter and switching-regulator system are formulated. An optimum low-pass and light-weight filter configuration is proposed.     

Adaptive Input Filter Compensation for Switching Regulators

An input filter is frequently employed between a switching regulator and its power source. However, its presence often results in degradation of dynamic performances and stability. The detrimental interaction is between an input filter and a switching regulator and is a function of the input filter parameters and also of the supply voltage. An earlier paper presented an analysis and design procedure aimed at developing a feed-forward loop to cancel this undesirable interaction. The feed-forward design is extended here to encompass a scheme that automatically accounts for changes in the supply voltage; the result is an adaptive compensation that tracks the input voltage variations. Experimental results are presented that confirm the adaptive nature of the design.     

压电陶瓷叠层作动器迟滞蠕变非线性自适应混合补偿控制方法

压电陶瓷叠层作动器的迟滞蠕变非线性特性严重影响了控制系统的稳定性及动态跟踪精度。针对其迟滞蠕变非线性补偿控制问题,提出了一种高精度动态补偿压电陶瓷叠层作动器非线性特性的自适应混合补偿控制方法,即迟滞蠕变前馈补偿与自适应滤波反馈补偿结合的前馈-反馈混合控制方法。采用改进的Prandtl-Ishlinskii（Modified Prandtl-Ishlinskii,MPI）模型对压电陶瓷叠层作动器迟滞蠕变非线性特性进行精细化建模,并得到其逆补偿模型进行前馈补偿。根据前馈补偿误差,采用自适应滤波反馈控制对输入信号进行实时调控,实现对压电陶瓷叠层作动器的迟滞非线性及lg（t）型蠕变特性的实时精确补偿控制。数值仿真与实验结果表明,相比于常规前馈迟滞蠕变补偿,所提出的自适应混合补偿控制方法可以有效降低压电陶瓷叠层作动器的迟滞补偿误差,极大提高了迟滞蠕变非线性动态跟踪精度以及自适应性。     

Third-Order Loop Filter Design for Acceleration-Rate Tracking

A perfect third-order loop filter design that can be implemented as a digital filter is obtained which minimizes the noiseless steady-state acceleration rate (jerk) error for a fixed loop noise bandwidth. Simulations were performed to obtain transient responses of the third-order loop plus a sample fourth-order loop under a jerk input. The results enable one to obtain a loop design that minimizes the loop noise bandwidth required for a given steady-state jerk error and thus obtain better noise jitter performance.     

直升机发动机控制系统与旋翼/动力传动扭振系统耦合稳定性分析

直升机的发动机通过传动系统驱动旋翼及尾浆,形成了一个机械扭振系统,这个系统又与发动机控制系统相互耦合构成一个闭环的动力学系统。本文针对某型直升机建立了相应闭环系统的数学模型,分析、判断闭环系统的稳定性及稳定裕度;研究了使用下陷滤波器来改善耦合系统稳定性的设计思路和参数调整的试验方法。     

基于自适应FIR算法的交流伺服系统前馈控制

永磁同步电机(PMSM)交流伺服控制系统中由于电子器件的开关引起相电流非正弦变化,经坐标变换得到的交直轴电流含有谐波成分,引起电流环振荡及电磁转矩脉动。在分析相电流与交直轴电流高次谐波关系,以及交直轴电流高次谐波对电磁转矩影响的基础上,提出了一种基于自适应FIR滤波器的交流伺服系统前馈控制策略,并在该方法的基础上提出了变步长因子算法,根据误差值改变步长因子,在提高滤波器收敛速度的同时减小超调。该算法与传统的一阶低通滤波器相比,相位不滞后,灵敏度更高,且系统稳定。改进后的控制策略有效地降低交直轴电流谐波,抑制电流环振荡及电磁转矩脉动,提高PMSM交流伺服控制系统稳定性及动态响应。通过仿真与试验证明了该方法的可行性。     

New Control Technique in dc/dc Regulators for Space Applications

A new type of control loop is presented for dc/dc regulators, based on the use of a linear analog to pulsewidth modulator. This function, which is independent of operating frequency, permits high sampling frequencies. Combined with a limiter of the analog input, limitation characteristics are automatically available, without any extra sensing on the hot line. The independence of parameters f0 and ?1 is demonstrated, and application of the loop to control the regulator output characteristics is shown. This flexibility finds useful applications in high-power systems (1 kW) by permitting parallel unit operations and utilization of modular units.     

无人机机动轨迹跟踪系统设计

对无人机机动飞行轨迹跟踪系统的内环姿态控制律和外环轨迹跟踪控制律两部分分别进行了设计。利用非线性动态逆方法设计了内环姿态控制律。外环轨迹跟踪控制律采用逆动力学前馈加模糊反馈的控制结构,提高系统对飞行条件及期望轨迹剧烈变化时的跟踪精度。仿真结果表明,所设计的系统能够控制无人机精确跟踪指定的机动轨迹,且相对于固定增益系统具有更好的鲁棒性。     

Feedforward maximum power point tracking of PV systems using fuzzy controller

A feedforward maximum power (MP) point tracking scheme is developed for the interleaved dual boost (IDB) converter fed photovoltaic (PV) system using fuzzy controller. The tracking algorithm changes the duty ratio of the converter such that the solar cell array (SCA) voltage equals the voltage corresponding to the MP point at that solar insolation. This is done by the feedforward loop, which generates an error signal by comparing the instantaneous array voltage and reference voltage. The reference voltage for the feedforward loop, corresponding to the MP point, is obtained by an off-line trained neural network. Experimental data is used for off-line training of the neural network, which employs back-propagation algorithm. The proposed fuzzy feedforward peak power tracking effectiveness is demonstrated through the simulation and experimental results, and compared with the conventional proportional plus integral (PI) controller based system. Finally, a comparative study of interleaved boost and conventional boost converter for the PV applications is given and their suitability is discussed.     

飞机的伺服-气动弹性稳定性

现代飞机的自动控制系统都具有控制与增稳两种功能,它通过伺服系统与控制面相连。这种系统与控制对象——飞机之间形成一个闭合回路,如图1所示。考虑到控制系统与飞机两者间动力学特性的相互作用,构成一系列性质各异的回路问题。根据他们不同的外部条件和涉及面的特性差异,形成了多种现象,其中一个引人注目的问题就是闭合回路的稳定性问题。通常在把控制系统或结构作为单独分支而设计时是稳定的,而把它们串联起来成为一个整体时,系统的稳定性就发生了变化。     

Battery charger design for the Columbus MTFF power system

A novel pulsewidth-modulated (PWM) dc-dc converter topology is proposed for the battery charge regulator (BCR) of the Columbus Man-Tended Free-Flyer (MTFF) power system. The system is a regulated bus system. Bus voltage control is implemented at the input of the BCR. The use of a conventional buck topology with PWM conductance control at the input results in a second-order behavior. A study of new PWM dc-dc converter topologies has been made to attain a suitable topology. The proposed converter topology is designed and a breadboard including the control loop has been built and tested. The experimental results show that the converter operates according to the design constraints.     

含位置给定轨迹优化的位置伺服复合控制系统研究

位置动态响应速度快和响应无超调是目前高性能位置伺服系统的两个重要指标。单纯的比例或比例微分位置调节器无法同时满足这两个要求,所以提出了一种新型定位复合控制策略。首先为保证运动过程柔滑无冲击而设定速度余弦函数曲线给定,从而根据平滑变化的速度给定对位置给定信号进行轨迹优化,避免了加速度突变带来的冲击。系统控制结构上提出在前馈控制的基础上引入位置伪微分负反馈控制环节,该环节增加了系统阻尼,减少位置超调量,同时结合前馈控制保证了位置快速跟踪性能。由于采用了伪微分结构代替位置微分运算,避免了微分带来的量化噪声干扰,进一步提升了系统跟踪性能。最后给出了结构参数的取值范围。仿真和试验结果验证了该控制策略的可行性和有效性。     

An efficient active ripple filter for use in DC-DC conversion

When low ripple is required from a switched mode dc-dc converter, dissipative active filters offer an alternative to passive LC and coupled inductor filters. Analytical and experimental results are presented for a simple active ripple filter. The filter employs a pair of current transformers as sensors for feedforward and feedback control and two metal-oxide-semiconductor field-effect transistors (MOSFETs) as cancellation current drivers. Measurements demonstrate good ripple attenuation up to 5 MHz, more than 70 dB being obtained at 100 kHz, the switching frequency of a test converter. The overall efficiency was measured as 95%, with room for further improvement. The filter is suitable for input and output smoothing in dc-dc converters for aerospace and other critical applications     

基于鉴相器的矢量跟踪环设计

基于鉴相器的矢量跟踪环是锁定导航卫星码和载波的一种跟踪算法,这种算法适合于在弱信号环境下进行跟踪。矢量环不仅充分利用信号跟踪和导航状态解算之间的内在耦合关系,而且每一通道中采用鉴相器和锁频环结合的方式,系统一步内完成信号跟踪和导航解算任务。反馈控制量NCO是由导航滤波器和环路内部滤波器共同产生。实验表明,矢量跟踪环具有快速重捕获特性,能够在弱信号的环境下运行,比起传统环路有更小的跟踪误差。     

考虑驾驶仪动态性能的指令滤波反演制导律

针对攻击机动目标的制导问题,设计了一种考虑自动驾驶仪性能、输入项约束的指令滤波反演制导律。首先,基于三维空间内弹目相对运动模型,采用反演递推方式设计制导律。针对传统反演控制存在的"微分膨胀"问题,引入指令滤波器对虚拟量进行过滤计算。考虑硬件计算能力的约束,引入自动驾驶仪二阶动力学模型减少控制过程延迟,并利用饱和函数和低通滤波器对输入项进行约束。此外,针对机动目标设计了一种扩张状态观测器来获取其加速度。通过Lyapunov理论证明了所设计闭环制导系统的稳定性。通过仿真实验验证了该制导律相有效性及优越性。     

Comments on "A Novel Feedforward Compensation Canceling Input Filter-Regulator Interaction"

This correspondence clarifies the conditions under which the canceling of the input filter dynamics of a buck regulator by partial state feedback can be performed.     

Numerical simulation of a cabin ventilation subsystem in a space station oriented real-time system

An environment control and life support system(ECLSS) is an important system in a space station. The ECLSS is a typical complex system, and the real-time simulation technology can help to accelerate its research process by using distributed hardware in a loop simulation system. An implicit fixed time step numerical integration method is recommended for a real-time simulation system with time-varying parameters. However, its computational efficiency is too low to satisfy the real-time data interaction, especially for the complex ECLSS system running on a PC cluster. The instability problem of an explicit method strongly limits its application in the ECLSS real-time simulation although it has a high computational efficiency. This paper proposes an improved numerical simulation method to overcome the instability problem based on the explicit Euler method. A temperature and humidity control subsystem(THCS) is firstly established, and its numerical stability is analyzed by using the eigenvalue estimation theory. Furthermore, an adaptive operator is proposed to avoid the potential instability problem. The stability and accuracy of the proposed method are investigated carefully. Simulation results show that this proposed method can provide a good way for some complex time-variant systems to run their real-time simulation on a PC cluster.     

高精度液压仿真转台鲁棒控制

 针对液压仿真转台具有时变不确定性、复杂外干扰等特点和高精度控制性能要求,提出了一种鲁棒复合控制结构,该结构由鲁棒内回路补偿器、外回路反馈控制器和输入信号前馈补偿器三部分组成。其中,鲁棒内回路补偿器用来抑制外干扰和时变不确定性的影响,外回路反馈控制器的作用是保证闭环系统的整体性能,输入信号前馈补偿器实现对系统动态时滞的补偿,以保证对参考信号的精确跟踪。以某型液压仿真转台内环为例,首先根据所提出控制策略的基本思想,给出了控制系统的具体设计过程,然后,进行了阶跃响应、低速跟踪和正弦响应试验。试验结果表明,所提出的鲁棒控制策略是有效的和可行的。     

电动舵机中的电流环分析及校正

以电动舵机中电流控制问题为研究对象,通过对直流电机电流数学建模及频域分析,阐述了常规电流环控制器校正后的电流频率响应特性。针对电流负反馈容易引入测量噪声、采样延时带来不稳定等问题,提出呆用陷波滤波器串联校正电流的频率特性,并给出了滤波器参数设计方法。分别对串联校正和电流负反馈控制进行了实验验证,结果表明采用陷波滤波器串联校正能够抑制峰值电流,与电流环比例控制效果接近,其实现简单、稳定性好。