【作者】 邵明东；

【导师】 杨玉珍； 陈阳舟；

【作者基本信息】 北京工业大学 ， 控制理论与控制工程， 2004， 硕士

【摘要】 摘 要 本文针对变频恒压供水系统中控制对象模型难于精确建立以及水泵电机驱动电源切换控制中的问题，提出了自适应逆控制和自适应模糊控制策略以及锁相环同步切换最优控制方案，并进行了基于 DSP 控制器的模拟供水系统调试以及基于 Matlab 环境下的锁相同步控制仿真，结果证明了控制策略的有效性，明显改善了供水系统的控制性能。 由于供水系统的数学模型具有严重的非线性和时变性，无法用线性化方法近似，传统 PID 控制器的参数很难调整、适应性差。针对此问题，本文设计了自适应逆控制器。自适应逆控制通过在线辨识对象模型以获取对象的运行状态，然后以此运行状态为信息，用自适应算法修改控制器参数，从而使控制器实时跟踪被控对象的变化，实施正确的控制。论文中给出了在模拟供水实验装置上的调试波形，可看出显著提高了供水系统水压的控制精度。由于非线性自适应逆控制算法采用基于递归神经网络的 NARX 滤波器实施建模与控制，计算量较大，需要运算速度较高的微处理器，使得硬件成本较高。为此又设计了自适应模糊控制器，获得了较好的控制性能。该方法不需要辨识被控对象的模型，因而计算量小，有利于系统的实时控制，及降低设备的成本，便于推广应用。 本文针对供水系统中的另一问题，即：在变频供水系统中多台水泵并联运行，变频电源驱动的水泵电机切换到工频电源时，由于水泵电机的反电动势与工频电源在频率和相位上的不确定性，可能产生很强的过电流，会导致系统的自动开关跳闸，并对电器元件产生强烈的冲击。采用锁相同步切换方式，可显著减小冲击电流。但是一般的锁相环采用 PI 控制，响应速度慢，切换过程长。针对此问题，本文提出时间最优控制及基于趋近率的变结构控制策略，并对锁相环捕获过程进行了仿真研究，给出了 Matlab 环境下的仿真波形。结果表明变结构控制在捕获时间和稳态精度的综合性能上优于 PI 控制。更多还原

【Abstract】 This paper deals with the problems in water supply system of constant pressure,where the accurate plant model is difficult to get and the power supplies of the pumpneed to switch. Those problems are resolved by adaptive inverse control, adaptivefuzzy control and synchronous transfer based on phase locking, respectively. The DSPhardware system of constant pressure control is tested on the analog of water supplysystem and the synchronous control of phase locking is simulated in Matlabenvironment. The findings prove the validity of the control strategies that improve theperformance of the water supply system. The model of the water supply system is intrinsic nonlinear and time variant, whichmakes it difficult to linearize the plant and tune the PID controller. Thus thetraditional PID controller cannot adapt to the changes. To tackle this problem, wehave designed an adaptive inverse controller and get high precise control, which canbe seen from the pressure waveforms of the experimental equipment. In this case, therun time states of the plant is achieved by the identification procedure and thisinformation is used to update the parameters of the controller by adaptive algorithmthat makes the controller can feed right control to the plant as the states changed.However, the nonlinear adaptive inverse control uses NARX filter as plant model andcontroller, which makes the computational complexity of the algorithm increase andthe cost of the hardware become high. So we also designed the adaptive fuzzycontroller that has no need to identify the model of the plant. It makes thecomputational complexity decrease, which helps the real time processing, reduce thecost and simplify the implementation. Another issue in water supply system is the parallel operation of multiple pumps.The main problem is, while the pump driven by the VFD is switched to the powerlines, large surge transient currents may be produced by the frequency and phasedifference between the power supply and the counter electromotive force of the motor,which will result in the failure of the automatic switches and the damage of the II<WP=6>摘 要electric equipments. Synchronous transfer based on phase locking is an advancedswitch mode that can reduce the surge transient currents. However, the generalphase-locked loop adopts PI control, which makes the response become slow and theswitch process long. To avoid this problem, this paper employs time optimal controland variable structure control by the reaching low method. The simulation of thecapture process, by Matlab, shows that the variable structure control is superior to PIcontrol both in capture time and steady state performance.更多还原