Structures of a digital PI controller for an electric drive

Various structures of PI controllers and peculiarities of their operation under conditions of saturation are considered. Literature data is reviewed and methods for calculation of a correction coefficient of the integral term for saturation condition are summarized. An original structure for correction of an input error of a controller to avoid improper accumulation of the integral term is proposed. Results are confirmed by simulation experiments.     

交直流调速系统通用数字控制器的实现

介绍了一种由16位单片机80C196MC构成的通用数字控制器。重点阐述了通用数字控制器的硬件电路和软件系统 ,并给出了采用该控制器实现的交直流调速系统及实验结果。     

A fuzzy gain scheduling PI controller application for an interconnected electrical power system

In this study, a fuzzy gain scheduled proportional and integral (FGPI) controller was developed to regulate and to improve the frequency deviation in a two-area electrical interconnected power system. Also, a conventional integral (I), a conventional proportional and integral (PI), and a fuzzy logic (FL), controllers were used to control the same power system for the performance comparison. Two performance criteria were utulized for the comparison. First, settling times and overshoots of the frequency deviation were compared. Later, the absolute error integral analysis method was calculated to compare all the controllers. All the models were simulated by Matlab 6.0-Simulink software. The simulation results show that the FGPI controller developed in this study performs better than the other controllers with respect to the settling time and overshoot, and absolute error integral of the frequency deviation.     

基于CIGRE HVDC控制器的PI参数可视化整定方法

提出一种PI控制器参数的可视化整定方法.该方法直接依据系统传递函数模型,在(Kp,Ki)平面上绘制稳定边界曲线,判断并确定其稳定区域即稳定集;然后在稳定集中选取并绘制满足频域性能指标的控制参数集;最后在频域参数优化的基础上,进行满足稳态性能指标、动态性能指标、超调量和上升时间等时域性能的参数寻优,从而找到最佳的PI参数集.对CIGRE HVDC基准模型的仿真验证了该方法的正确性.     

A digital signal processor based robust integral-proportional controller for an induction motor servo drive

A digital signal processor (DSP) based computer controlled indirect field oriented induction motor servo drive with robust control characteristics is proposed in this paper. First, the DSP based induction motor servo drive is implemented and the dynamic model of the system at the nominal condition is identified by a curve fitting technique. Based on this model, an integral-proportional controller is quantitatively designed to match the prescribed position tracking specifications. Then a simple robust controller is designed and augmented to reduce the performance degradation due to uncertainties.     

数字PI控制器的参数辨识及实验验证

风电机组控制系统中PI控制器较多,需要辨识各PI控制器的参数。针对数字PI控制器,基于可辨识性理论,直接应用PI控制器不同状态的输入/输出数据,分析PI控制器参数的可辨识性,得到了其参数可唯一辨识的结论,并据此设计了PI参数辨识的具体算法。在此基础上,根据电机转速控制实验装置实测的数据,运用可辨识性分析步骤中的参数辨识算法,辨识得到高精确度的PI参数。在施加脉冲群干扰试验和振荡波干扰试验条件下,算法也能准确地辨识PI控制器参数,具有良好的鲁棒性,验证了理论分析的正确性和辨识方法的可行性。     

Adaptive-backstepping-based design of a nonlinear position controller for an IPMSM servo drive

This paper presents the design of a novel nonlinear position controller for an interior permanent-magnet synchronous motor (IPMSM) servo drive. The motor model equations provide the basis for the proposed controller, which is designed with the adaptive backstepping technique. Various system uncertainties, particularly mechanical-parameter uncertainties, are incorporated in the design of the controller. Using Lyapunov's stability theory, it is verified that the control variables are asymptotically stable. The complete drive system is then simulated with MATLAB/Simulink software. Performance of the proposed adaptive-backstepping-based nonlinear position controller (ABNPC) is investigated under different dynamic operating conditions such as step changes in command positions, step changes in load, and parameter variations. The results indicate that the proposed ABNPC-based IPMSM drive could be a candidate for real-time industrial servo motor drive applications.     

Feedback-signal prediction for a deadbeat PI controller

This paper considers an algorithm of feedback-signal prediction for implementing a current loop with a PI controller tuned for deadbeat control. The algorithm takes into account errors of incorrectly set inductance and the presence of a filter in the feedback signal. An algorithm for correcting the inductance of the control-object model and the proportional coefficient of the current PI controller is implemented. The final algorithm was tested taking into account measuring-channel discreteness.     

A fast variable structure current controller for an inductionmachine drive

Field-oriented control of a current source inverter induction machine system is essentially performed by controlling both the magnitude and orientation of the primary current vector. The interaction of the machine counter-EMF (electromotive force) and rectifier output voltage plays an important role in the current magnitude control. The traditional current loop design technique, which is suitable for DC drives, is not effective in the design of AC drivers due to this interaction. A new current loop modeling and control method is presented. This fast and robust current control technique enhances the entire system performance     

Implementation of an artificial-neural-network-based real-time adaptive controller for an interior permanent-magnet motor drive

This paper presents the implementation of an artificial-neural-network (ANN)-based real-time adaptive controller for accurate speed control of an interior permanent-magnet synchronous motor (IPMSM) under system uncertainties. A field-oriented IPMSM model is used to decouple the flux and torque components of the motor dynamics. The initial estimation of coefficients of the proposed ANN speed controller is obtained by offline training method. Online training has been carried out to update the ANN under continuous mode of operation. Dynamic backpropagation with the Levenburg-Marquardt algorithm is utilized for online training purposes. The controller is implemented in real time using a digital-signal-processor-based hardware environment to prove the feasibility of the proposed method. The simulation and experimental results reveal that the control architecture adapts and generalizes its learning to a wide range of operating conditions and provides promising results under parameter variations and load changes.     

电力参数交流同步采样截断误差的估计

对电力参数的理想情况（标准正弦量）采样数字化测量的典型算法（梯形法）的截断误差进行了分析，给出了误差与采样点数的关系；根据国家关于电能质量和公用电网谐波的标准规定，对非正弦状态下的误差也做出了符合实际的估计，在电网正常（允许畸变）情况下截断误差与采样点数的关系与理想波形时相同，这些结论可在采用交流采样技术的电力参数测量装置设计时进行误差分析提供参考。     

A robast digital control system for an asynchronous electric drive

Polynomial methods for synthesizing robast digital regulators of a frequency-controlled asynchronous electric drive are considered. It is shown that the use of robast regulators makes it possible to significantly reduce sensitivity to changing object parameters and increase the adjustment of disturbing actions. The possibility to create qualitative systems for an electric drive without a unit of compensating cross connections is grounded.     

Grid power quality enhancement using an ANFIS optimized PI controller for DG

Grid frequency variation causes phase angle deviation in current with respect to voltage. This is sensed at the phase-locked loop in the controller. In past studies the effect of grid frequency variation is neglected while designing the controller for power quality restoration. When modern grids are connected to large numbers of non-linear loads and various types of distributed generation (DG), it results in continuous variation in grid frequency. Thus it is necessary to consider the grid frequency variation for effective power quality restoration. However, tuning of conventional PI controller gains considering frequency variation is very difficult. Thus it is necessary to develop an adaptive intelligent nonlinear controller to tackle the effects of frequency variation, voltage distortion and non-linear load simultaneously. This paper presents the importance of considering the effects of the frequency variation, grid voltage distortion and non-linear load, while designing and deploying a controller for power quality restoration. The proposed controller supplies power to local load as well as transferring surplus power to the grid from DG along with the additional benefit of improving grid power quality. A DG with an ANFIS optimized PI current controller for power quality enhancement is proposed. The method is economical as it requires no additional hardware. Results are compared with PI, PI-RC and fuzzy current controllers to validate the effectiveness of the proposed controller.     

Age-of-information-aware PI controller for load frequency control

Open communication system in modern power systems brings concern about information staleness which may cause power system frequency instability. The information staleness is often characterized by communication delay. However, communication delay is a packet-centered metric and cannot refect the requirement of information freshness for load frequency control (LFC). This paper introduces the age of information (AoI), which is more compre-hensive and informative than the conventional communication delay modeling method. An LFC controller and com-munication are integrated into the design for LFC performance improvement. An AoI-aware LFC model is formulated frst, and considering each allowable update period of the smart sensor, diferent AoI-aware PI controllers are then designed according to the exponential decay rate. The right AoI-aware controller and update period are selected according to the degree of frequency fuctuation of the power system. Case studies are carried out on one-area and two-area power systems. The results show the superior performance of the AoI-aware controllers in comparison to the delay-dependent controllers.     

电力参数非同步采样误差分析

对用单片机测电力参数在非同步采样时的测量误差进行了分析，得出一般情况下的误差估计；针对典型算法(复化梯形算法)给出准确的误差公式，并由此得到减小误差的方法。这些结论可为交流采样技术的电力参数测量仪表在设计时进行误差分析提供参考。     

Tuning a PID controller for a digital excitation control system

Some of the modern voltage regulator systems are utilizing the proportional, integral, and derivative (PID) control for stabilization. Two PID tuning approaches, pole placement and pole-zero cancellation, are commonly utilized for commissioning a digital excitation system. Each approach is discussed including its performance with three excitation parameter variations. The parameters considered include system loop gain, uncertain exciter time constants, and forcing limits. This paper is intended for various engineers and technicians to provide a better understanding of how the digital controller is tuned with pros and cons for each method.     

DStatCom regulation by a fuzzy segmented PI controller

This paper presents a segmented PI controller for the 84-pulses DStatCom connected to the electric power system (EPS) and subjected to several common disturbances in voltage and load levels. The 84-pulses signal is obtained by combining one twelve-pulses voltage source converter (VSC) with an asymmetric single-phase seven-level converter, adding an injection transformer. This structure allows a reduced VSC output's total harmonic distortion. The synchronizing strategy ties the DStatCom to the EPS in an automatic way, preventing phase and frequency problems. PI controllers exhibit good performance around nominal conditions but they do not tolerate severe disturbances. Thus, a segmented PI strategy based on the error and error's variation is utilized and selected according to fuzzy rules. Simulations demonstrate the appropriateness of the proposal.     

基于鲁棒调节器的无刷直流电机速度控制研究

本文提出了无刷直流电机的一种线性时变模型，分析了影响电机速度控制的负载扰动，在此基础上，设计了一种鲁棒速度控制器，对其设计方案进行了阐述，同时，针对速度不易检测的问题设计了全维转速观测器，最后，对速度控制系统进行了实验研究。