Application of Memristor-Based Controller for Loop Filter Design in Charge-Pump Phase-Locked Loops

In this work, a monotonic increasing piecewise-linear (PWL) memristor-based proportional-integral (PI) controller is analyzed. A periodic rectangular pulse current source is used as the input signal, and the proportionality constant of the PWL memristor-based PI controller is varied according to the amount of charge that passes through the memristor. A circuit is proposed to achieve zero net-charge injection for the memristor so that the memristance of the PWL memristor can be varied in the subsequent period. The proposed PWL memristor-based PI controller can be used in the design of the loop filter for the charge-pump phase-locked loop for achieving a faster dynamical response from an unlocked state to a locked state compared to conventional fixed proportional constant PI controllers.     

基于TMS320F2812无刷直流电机控制系统设计

设计一种基于TMS320F2812的无刷直流电机控制系统;详细介绍了转子位置检测电路、相电流检测电路、驱动电路以及保护电路设计;给出相应的硬件电路.该系统采用三环控制.其中,位置环采用PI调节器;速度环采用参数自整定模糊PID控制:电流环采用电流滞环控制.该设计方案电路简单,可靠性强,具有较高的应用价值.同时,实验结果也验证了该方法的有效性.     

A two-layered fuzzy logic controller for systems with deadzones

Existing fuzzy control methods do not perform well when applied to systems containing nonlinearities arising from unknown deadzones. In particular, we show that a usual "fuzzy PD" controller applied to a system with a deadzone suffers from poor transient performance and a large steady-state error. In this paper, we propose a novel two-layered fuzzy logic controller for controlling systems with deadzones. The two-layered control structure consists of a fuzzy logic-based precompensator followed by a usual fuzzy PD controller. Our proposed controller exhibits superior transient and steady-state performance compared to usual fuzzy PD controllers. In addition, the controller is robust to variations in deadzone nonlinearities. We illustrate the effectiveness of our scheme using computer simulation examples.<>     

Fuzzy logic control of a space-vector PWM current regulator forthree-phase power converters

This paper presents a fuzzy logic implementation of space-vector pulse-width modulation (PWM) for three-phase power converters. The conventional space-vector PWM current regulator implementation is generally computationally complex. The fuzzy logic controller implementation relieves the processor of a number of computations, thereby accommodating a less expensive microprocessor. The AC-side rectifier voltages are used as fuzzy-state variables. The fuzzy logic control has two outputs: magnitude and angle of reference voltage. Both conventional space-vector PWM and the fuzzy logic controller are implemented to evaluate performance using a 16-b microcontroller (68HC16). Experimental results are provided for both controllers at the same operating point, where the power drawn by the load is about 3 kW. The fuzzy logic controller reduces the computational burden on the processor by about 30%     

Experimental Comparison of Digital Implementations of Single-Phase PFC Controllers

This paper presents the design and the digital implementation of three controllers for a single-phase power factor corrector (PFC). Based on an averaged system model, an adaptive nonlinear control strategy is first designed, followed by a digital redesign of the standard cascaded linear controller and a notch-filter-based variant. All three controllers have been verified via simulation in Simulink using a continuous time plant model and a discrete time controller. Real-time implementation is performed on an experimental testbed utilizing a rapid prototyping tool. The three controllers are experimentally compared for steady-state performance and transient response. It is shown that the nonlinear controller gives a better steady-state performance, whereas the linear strategy and the notch-filter-based variant have a faster dynamic response. Furthermore, although the notch-filter-based linear design shows promise in simulation, practical difficulties degrade its experimental performance. Performance metrics are tabulated for easy comparison.     

A fuzzy sliding controller for nonlinear systems

It is well known that sliding-mode control can give good transient performance and system robustness. However, the presence of chattering may introduce problems to the actuators. Many chattering elimination methods use a finite DC gain controller which leads to a finite steady-state error. One method to ensure zero steady-state error is using a proportional plus integral (PI) controller. This paper proposes a fuzzy logic controller which combines a sliding-mode controller (SMC) and a PI controller. The advantages of the SMC and the PI controller can be combined and their disadvantages can be removed. The system stability is proved, although there is one more state variable to be considered in the PI subsystem. An illustrative example shows that good transient and steady-state responses can be obtained by applying the proposed controller     

New Fuzzy Control Strategies Applied to the DFIG Converter in Wind Generation Systems

This paper presents new fuzzy control strategies which may be applied to the converter connected to the rotor of doubly fed induction generators (DFIG) composing a variable speed wind generation system connected to a real electrical grid. The fuzzy control proposed strategies are of the type supervised “look-up-table”. The performance of these intelligent controllers are compare with the fixed parameters PI controllers for fault ocurrence in the power system. The fuzzy controllers are supposed to better the transient performance of the electrical power system as compared with the conventional PI controllers. The obtained results from simulation studies have of the fuzzy controllers. To formulate the simulation studies an equivalent mathematical model of a significant number of wind turbines was implemented using the MATLABTM software packcage.     

New hybrid fuzzy controller for direct torque control induction motor drives

A new hybrid fuzzy controller for direct torque control (DTC) induction motor drives is presented in this paper. The newly developed hybrid fuzzy control law consists of proportional-integral (PI) control at steady state, PI-type fuzzy logic control at transient state, and a simple switching mechanism between steady and transient states, to achieve satisfied performance under steady and transient conditions. The features of the presented new hybrid fuzzy controller are highlighted by comparing the performance of various control approaches, including PI control, PI-type fuzzy logic control (FLC), proportional-derivative (PD) type FLC, and combination of PD-type FLC and I control, for DTC-based induction motor drives. The pros and cons of these controllers are demonstrated by intensive experimental results. It is shown that the presented induction motor drive is with fast tracking capability, less steady state error, and robust to load disturbance while not resorting to complicated control method or adaptive tuning mechanism. Experimental results derived from a test system are presented confirming the above-mentioned claims.     

Design of incremental fuzzy PI controllers for a gas-turbine plant

In this paper, incremental fuzzy proportional integral (PI) speed and temperature controllers for a heavy-duty gas-turbine plant are presented. To improve performance, an analysis of incremental fuzzy PI control is provided, and new fuzzy control rules are proposed. In applying the fuzzy PI control to a gas-turbine plant, all gains are optimized by an adaptive genetic algorithm. We show the performance improvement of the proposed controller compared with conventional PI controller via simulations.     

A new fuzzy logic-based controller design method for DC and ACimpressed-voltage drives

This paper deals with the design of fuzzy logic-based controllers (FLBC) for DC and AC electric drives. Industrial drives employ the cascaded PI control with a subordinated current control loop to make sure that the current does not exceed the admissible value and improve dynamic performances. The nonlinear FLBC characteristics permit one to achieve the performances of the cascaded control using only one control loop. This is feasible by a suitable choice of the scaling factors together with the rules of the fuzzy controller. The authors propose a minimum number of rules and the criteria, based on physical considerations, to determine the input and output gains instead of using the trial and error procedure. The designed FLBC is able to control the speed of a DC drive as well as the rotor speed and flux of a vector-controlled induction motor drive. Computer simulations show the effectiveness of the new fuzzy-controller design method. The reduced number of rules and membership functions and the application flexibility together with the possible implementation on low cost μPs lead the authors to think that the proposed tuning criteria will be widely adopted     

Sequential design of hysteresis current controller for three-phaseinverter

In this paper, a novel multivariable hysteresis current controller for three-phase inverters is presented. Hysteresis controllers are intrinsically robust to system parameters, exhibit very high dynamics, and are suitable for simple implementation. The main drawback of the hysteresis controller is a limited control on transistors' switching frequency. Very high switching frequency may result if three independent controllers are used. Multivariable solutions were proposed in the literature to solve the problem. In this paper, it is shown how the use of a sequential design for the multivariable controller can further contribute to transistors' switching frequency reduction, with no significant increase in the hardware implementation complexity. The proposed controller is illustrated and compared with other hysteresis controllers presented in the literature. It ensures a significant reduction of transistors' switching frequency with respect to the other tested controllers, under the same operating conditions. A prototype controller is also presented. The effects of noise captured by current sensors (especially Hall-effect type) on the performance of industrial hysteresis controllers are discussed. It is shown how the sequential design of the controller can also help in solving this critical problem. Experimental results are reported to confirm the quality of the proposed controller. The system stability condition is derived in an appendix     

Comparative analysis of fixed and sinusoidal band hysteresiscurrent controllers for voltage source inverters

A hysteresis controller with a sinusoidal band for current regulation is described. The behavior of the conventional fixed-band controller and the proposed sinusoidal band controller has been thoroughly studied. Simulation results demonstrate that with no lockout (permitting a very high switching frequency) the current waveform can be confined within the desired hysteresis bands. At low lockout frequencies the current is not confined within the hysteresis bands and both fixed and sinusoidal band controllers give a high ripple. The study also shows that with a reasonable lockout frequency, a sinusoidal band control results in a reduced ripple and lower harmonic content. However, the switching frequency is higher with the sinusoidal bands. This should not be a major concern with the availability of fast switching devices that allow higher lockout frequencies     

自调整模糊控制器在永磁同步电机矢量控制中的应用

模糊控制器对系统模型依赖程度低,性能优异,已经在许多场合得到了应用。传统的永磁同步电机矢量控制系统采用PI控制,在电机参数变化或负载波动较大时性能不佳。针对这一问题,本文设计了一种基于量化因子和比例因子自调整的自适应模糊控制器。仿真结果表明,与传统PI和基本模糊控制器相比,这种参数自调整模糊控制器能使系统具有更好的抗扰性和更优良的稳态性能。     

压电陶瓷精密控制系统的自适应模糊控制器研究

针对压电陶瓷等非线性系统,建立压电陶瓷微精密位移系统模型,并将模糊控制器替换传统的比例、积分和微分(PID)控制器,实现对PID参数的在线自整定。对模糊控制器的控制变量及论域等级等进行了研究及制定,并对其进行MATLAB仿真。实验结果表明,模糊逻辑控制器比传统PID控制器的响应速度快,超调量小,且控制策略简单易行。     

Flux-based two-degrees-of-freedom algorithm for three-phase electronic converter control

This letter integrates the tracking robustness of two-degrees-of-freedom control and fast dynamic response of flux-based, pulse-width modulation to develop a new current controller for high performance, three-phase electronic converter control. Theoretical analysis shows that the controller can simultaneously achieve good steady-state, transient and harmonic performance, which are challenges not previously met by existing current controllers reported in the literature. Experimental results are presented to verify the performance and practicality of the proposed controller.     

Constant-frequency sliding-mode and PI linear controllers for powerrectifiers: a comparison

Constant-frequency sliding-mode and linear proportional integral (PI) cascaded controllers (internal current loop and external output voltage control loop) for 12-pulse thyristor rectifiers are designed, using new models and convenient assumptions, and their performances compared. The use of sliding-mode control on line-commutated power converters implies the use of fixed-frequency sliding-mode design, originating steady-state errors. These are eliminated using a higher order switching function, with fourth-order Bessel polynomial coefficients, to minimize the response time and to eliminate the overshoot in the reaching mode. Comparisons are made using simulations (MATLAB/SIMULINK blocks) and experimental results. The sliding-mode controllers, as well as the PI controllers, need almost the same hardware and present no steady-state errors and no output voltage overshoots. Besides allowing a faster dynamics than the PI controllers, the proposed sliding-mode approach provides a new, nonlinear theoretical frame for solving the control problem of power rectifiers with output filters     

永磁同步电机的双闭环调速系统设计

永磁同步电机因其优越的性能近年来得到了广泛应用。针对双闭环控制器参数整定困难所导致的控制效果不佳的问题,文中提出了基于极点配置和Ramp函数的改进型双闭环PI控制器。从永磁同步电机矢量控制算法的角度出发,建立了速度、电流双闭环解耦控制的系统模型,并在此模型下论述了速度环、电流环控制器的设计方法,给出改进后双闭环控制器参数的计算结果。对所研究方法分别进行了计算机仿真和实际试验,结果表明优化后的系统减小了系统过冲,缩短了稳定时间,提高了系统动态响应,具有良好的工程意义。     

电压模式Buck-Boost变换器变论域模糊PI控制

电压模式Buck-Boost变换器是一个典型的非最小相位系统。根据DC-DC Buck-Boost变换器的工作特性,运用状态空间平均法建立其小信号模型,据此设计PI控制器参数。Buck-Boost变换器是一个时变的非线性系统,传统PI控制难以达到最优的控制效果,由此采用模糊PI控制来规避PI控制的弊端。针对模糊PI控制在被控量变化较大时,控制精确度变差的问题,设计了模糊论域自适应伸缩变化的变论域模糊PI控制器,对Buck-Boost电路进行控制。通过Matlab/Simulink环境仿真,实验结果表明,变论域模糊PI控制具有更好的动态控制性能。     

A method for improving the robustness of PID control

In this paper, an effective method is proposed for robust proportional-integral-derivative (PID) control that is easily implementable on commonly used equipment such as programmable logic controller (PLC) and programmable automation controller (PAC). The method is based on a two-loop model following control (MFC) system containing a nominal model of the controlled plant and two PID controllers. Basic features exhibited by the MFC structure are presented, and a technique to tune both component controllers is given. The proposed structures have been implemented in a programmable logic controller and tested on control plants with perturbed parameters. Also, the proposed control system has been checked for its performance in cases when the operation of PID controllers is based on fuzzy logic. Tuning rules for the fuzzy controllers in the presented MFC system have been proposed. Results of tests lend support to the view that the proposed control structures may find wide application to robust control of plants with time-varying parameters.     

一种模糊-PI双模控制系统的仿真与设计

为了提高系统的控制性能,综合了模糊控制和PID控制的优点,提出一种基于模糊-PI双模控制器设计方法。典型的二维模糊控制器因缺少积分环节,难以消除稳态误差,控制的精度常常不能满足系统要求;而PI控制器具有良好的消除稳态误差的作用,所以将其与模糊控制器结合构成复合控制器。通过Matlab/Simulink仿真,结果表明,与经典的PID控制方式相比较,该控制方式在快速性、稳态性及准确性方面都有较大提高。