Sliding mode controlled multiphase buck converter with interleaving and current equalization

This paper presents a sliding mode control design of a multiphase power converter. The use of multiphase converters and an appropriate phase shift result in chattering reduction to the desired level at a given switching frequency in the so called “ripple cancellation” or “harmonic cancellation”. Additionally, this strategy considers sliding mode as a suitable substitute for Pulse Width Modulation because of the benefits in sliding mode control, i.e. the possibility of achieving desired system responses regardless of parameter changes. A 4-phase buck converter prototype was built and the controller was programmed in an FPGA. Experimental results show that chattering reduction, robust output regulation and phase current equalization are achieved, thus validating the proposed approach.     

Fixed frequency sliding mode control of renewable energy resources in DC micro grid

The rising cost of fossil fuels, their high depleting rate and issues regarding environmental pollution have brought the attention of the researchers towards renewable energy technologies. Different renewable energy resources like wind turbines, fuel cells and solar cells are connected to DC micro grid through controllable power electronic converters. In presence of these diverse generation units, robust controllers are required to ensure good power quality and to regulate grid voltage. This paper presents a sliding mode control based methodology to address the above mentioned challenges. The proposed technique keeps the switching frequency constant so that electromagnetic compatibility (EMC) issues can be solved with conventional filter design. Parallel operation of converter in DC micro gird is considered. Chattering reduction and power quality improvement by harmonic cancellation is proposed. A scaled down hardware for unregulated 11.5 V to 17.5 V input and 24V output is designed and tested. The experimental results show good performance of the controller under different loads and uncertain input voltage conditions. Moreover, the results show the robustness of the closed loop system to sudden variations in load conditions. Furthermore, a significant improvement in power quality is achieved by harmonic cancellation of chattering in the output of the converters.     

DC‐to‐AC power conversion on a ‘boost’ converter

In this article, we provide an approximate sliding mode control‐based solution to the DC–AC power conversion problem on a ‘boost’ converter. The approach uses the flatness property of the system as a pivot for generating a sequence of minimum phase output reference trajectory candidates. The generated candidates are obtained as differential parameterizations of the minimum phase inductor current variable in terms of the non‐minimum phase desired output capacitor voltage. The associated residual dynamics of the ideal sliding motions is shown to reasonably approximate the desired biased sinusoidal output capacitor voltage signal. Copyright © 2001 John Wiley & Sons, Ltd.     

无刷直流电动机积分反演模糊滑模控制

针对普通的无刷直流电动机控制策略受电动机本身因素影响,难以达到理想效果的问题,介绍了一种积分反演自适应滑模变结构控制和模糊控制相结合的控制器。该控制器在滑模面中加入积分项,实现了对速度信号的无静差跟踪,提高了系统的稳态精度;用模糊控制器来解决切换控制增益设定只能靠经验的问题;采用模糊控制算法对不确定性进行估计,有效地减小了滑模控制方法带来的抖振;为了进一步提高控制性能,重新设计了趋近律。仿真结果表明,该控制器能够大幅提升无刷直流电动机控制系统的性能。     

Simplex sliding mode methods for the chattering reduction control of multi-input nonlinear uncertain systems

The simplex sliding mode control method is further developed by considering uncertain control systems non-affine in the control law. In order to reduce chattering effects, a set of integrators is added in the input channels. The augmented system is then controlled by a switching logic based on the simplex control method. As a result, the original control vector turns out to be continuous. A second order sliding mode observer is used when the sliding output is not available. Explicit conditions are identified about systems uncertainties and the simplex geometry in order to guarantee the convergence of the proposed methodology.     

SECOND‐ORDER TERMINAL SLIDING MODE CONTROL OF INPUT‐DELAY SYSTEMS

This paper proposes a second‐order terminal sliding mode control for a class of uncertain input‐delay systems. The input‐delay systems are firstly converted into the input‐delay free systems and further converted into the regular forms. A linear sliding mode manifold is predesigned to represent the ideal dynamics of the system. Another terminal sliding mode manifold surface is presented to drive the linear sliding mode to reach zeros in finite time. In order to eliminate the chattering phenomena, a second‐order sliding mode method is utilized to filter the high frequency switching control signal. The uncertainties of the systems are analysed in detail to show the effect to the systems. The simulation results validate the method presented in the paper.     

自治供电系统的一种混合控制

研究自治供电系统 (ASES)控制问题, 基于“状态空间区域划分”和“切换控制”原理, 提出一种混合型控制器. 仿真表明, 相比于近年来文献 [1]中提出的动态滑模变结构控制方案, 在保持系统基本性能前提下, 可有效克服该方案中不可避免的抖振与高频切换等严重问题.     

自治供电系统的一种混合控制

研究自治供电系统(ASES)控制问题,基于"状态空间区域划分"和"切换控制"原理,提出一种混合型控制器.仿真表明,相比于近年来文献[1]中提出的动态滑模变结构控制方案,在保持系统基本性能前提下,可有效克服该方案中不可避免的抖振与高频切换等严重问题.     

基于云模型的变桨距系统积分滑模控制

针对具有参数变化和外加干扰的变桨距风力发电系统,提出了一种基于云模型的积分滑模控制。在滑模控制中引入误差项的积分,并用状态量代替误差的导数,消除传统滑模控制需要期望输出信号导数已知的假设;利用云模型的不确定性推理方法,动态地调节切换增益;利用积分的方法对切换增益进行估计,估计出系统中不确定因素的界,有效地削弱系统的抖振。仿真结果表明:该控制器用于风速高于额定风速以上的变桨距控制系统中,具有较好的控制品质,对系统参数的不确定和外部干扰具有很强的鲁棒性。     

Continuous Finite‐Time Sliding Mode Control for Uncertain Nonlinear Systems with Applications to DC‐DC Buck Converters

This paper investigates the continuous finite‐time control problem of high‐order uncertain nonlinear systems with mismatched disturbances through the terminal sliding mode control method. By constructing a novel dynamic terminal sliding manifold based on the disturbance estimations of high‐order sliding mode observers, a continuous finite‐time terminal sliding mode control method is developed to counteract mismatched disturbances. To avoid discontinuous control action, the switching terms of a dynamic terminal sliding manifold are designed to appear only in the derivative term of the control variable. To validate its effectiveness, the proposed control method is applied to a DC‐DC buck converter system. The experimental results show the proposed method exhibits better control performance than a chattering free controller, such as mismatched disturbances rejection and smaller steady‐state fluctuations.     

TORA系统基于自调节滑模干扰补偿器的解耦滑模控制

针对欠驱动TORA系统,提出一种基于自调节滑模干扰补偿器的解耦滑模控制方法。所提出的控制方法无需系统不确定性上界的先验信息,对于系统不确定性具有良好的适应性。该控制方法包括设计一种自调节滑模干扰补偿器和一种新型的双幂次趋近律,所设计的自调节滑模干扰补偿器能够利用切换增益自适应算法准确逼近上界未知的系统不确定性,所提出的新型双幂次趋近律能够保证系统状态的快速趋近并抑制控制器的高频抖动。采用Lyapunov稳定性理论证明闭环控制系统的稳定性,并通过数值仿真实验验证所提出的控制方法的有效性。     

Chattering analysis in sliding mode systems with inertial sensors

Singularly perturbed relay control systems with second order sliding modes (SP2SM) are considered for modeling of sliding mode control systems with inertial sensors. It is shown that the asymptotically stable slow-motion integral manifold of a smooth singularly perturbed system, describing the motion of an original SP2SM in the second order sliding domain, is the asymptotically stable slow-motions integral manifold of the original SP2SM. For sliding mode control systems with inertial sensors sufficient conditions for the exponential decreasing of the amplitude of chattering and unlimited growth of frequency are found. A formula for asymptotic representation of 'ideal' switching surface oscillations is suggested for sliding mode systems with inertial sensors.     

用于离散滑模重复控制的新型趋近律

针对不确定离散时间系统, 提出一种新型的离散趋近律, 构造理想切换动态, 并基于理想切换动态设计离散滑模重复控制器. 在消除系统颤振的同时, 完全抑制周期扰动带来的影响, 改善控制品质. 分别推导了切换函数的绝对收敛层、单调收敛层和拟滑模带的边界, 用于刻画在不同控制器参数下闭环系统的趋近过程和拟滑模运动. 数值仿真和在伺服装置上的实验结果证实了所提出控制方法的有效性.     

Power rate exponential reaching law for enhanced performance of sliding mode control

In Sliding Mode Control (SMC), the control action can be split into two regions- the reaching phase and the sliding phase. Considerable research attention has been given to improve the reaching time so as to best utilize the benefit of robustness property of sliding mode motion. Attention has also been on alleviating and/or eliminating chattering during sliding mode motion so that smooth control is obtained which will not hinder practical applications. Exponential Reaching Law (ERL) is one of the methods reported in the literature for alleviating chattering in sliding mode. This paper proposes a Power Rate Exponential Reaching Law (PRERL) whereby substantial improvement both in reaching time and chattering alleviation are achieved compared to ERL. With ERL, the states do not settle at its desired position due to high frequency low magnitude chattering, thus limiting its practical utility. This drawback has been overcome in the PRERL method. Thus the benefits of the proposed method is many fold: reducing reaching time, improving chattering alleviation and ensuring settling of the states at its final position with considerable improvement in speed of response.     

基于模糊滑模控制器和两级滤波观测器的永磁 同步电机无位置传感器混合控制

针对传统带有滑模观测器的永磁同步电机控制系统中的转矩脉动大、抖振明显、反电动势估计精度差等 问题, 在速度环提出了基于双曲正弦函数的新型趋近率, 结合模糊控制思想对趋近率参数实现自整定, 设计了一种 基于新型趋近率的模糊积分滑模速度环控制器; 同时, 在滑模观测器中提出基于变截止频率低通滤波器和修正反 电动势观测器的两级滤波结构来抑制反电动势中的高频分量和纹波分量, 并对转子位置进行合理补偿, 设计了两级 滤波滑模观测器; 通过Lyapunov判据对本文提出的控制策略的稳定性进行了推导证明. 仿真结果表明, 与传统滑模 观测器相比, 本文控制器可使电机在启动和受到外部扰动时系统响应良好.     

基于自回归小波神经网络的感应电动机滑模反推控制

为了提高感应电动机控制的鲁棒性, 提出了一种新颖的感应电动机解耦模型. 基于感应电动机的解耦模型, 利用滑模控制和反推控制设计电动机的虚拟转矩和磁链电压控制器. 滑模开关增益的大小是造成系统抖振的关键, 采用自回归小波神经网络(Self-recurrent wavelet neural networks, SRWNN)在线估计滑模开关增益的大小可以有效降低滑模控制造成的抖振. 仿真结果表明基于SRWNN在线估计滑模开关增益的滑模反推控制方案可以有效提高感应电动机控制的鲁棒性, 同时降低了滑模控制造成的抖振.     

A frequency-shaping methodology for discrete-time sliding mode control

This paper proposes a frequency shaping methodology for performance enhancement of discrete-time sliding mode control for systems with narrow band disturbances. This approach augments the sliding mode surface as a dynamic feedback system and designs an ‘optimal’ shaping filter in the feedback loop based on H-infinity synthesis, which assures both the stability and the desired frequency-response characteristics of the sliding mode surface. Furthermore, this frequency-shaping technique is advanced to be parameter-dependent to improve the efficiency and flexibility. The methodology enables the design of sliding mode control in frequency domain, which is critically important for high-precision systems that are subjected to high-frequency disturbances. The proposed frequency-shaped sliding mode control is applied onto a hard disk drive in the presence of vibrations with multiple peak frequencies; effective vibration suppression is demonstrated through comprehensive simulation study.     

基于切换滑模控制的抖振抑制方法

针对一类复合干扰有界的不确定仿射非线性系统,提出一种切换滑模控制方法.首先利用3条滑模面将系统扩展动态空间划分为3个子空间,其中两个子空间组成滑动区,通过设计合适的切换规则和滑模切换增益,可以使滑动区满足到达条件和滑动条件,同时能够减小控制律不连续出现的区域和增益大小.为了增加设计的灵活性,给出一种可行设计方法.仿真实验结果表明,切换滑模控制方法在抑制抖振的同时具有较高的控制精度.     

UDE-based sliding mode control of DC–DC power converters with uncertainties

The DC–DC power converter plays an important role in solar systems to provide the stable DC bus voltage, but which is easily subject to various uncertainties and disturbances in practical operation. In this paper, an uncertainty and disturbance estimator (UDE) based sliding mode control approach is applied to improve the performance of power converters. The UDE is designed for the estimation of both the matched and mismatched uncertainties. To address the mismatched uncertainties, an adaptive sliding mode function is constructed with the compensation of the estimated uncertainties, which renders a chattering-free robust control law. Simulation and experimental results illustrate that the proposed control scheme achieves good dynamic performance, strong robustness and chattering reduction in the presence of uncertainties and disturbances     

无抖振离散滑模输出反馈控制方法及仿真研究

针对离散时间系统,提出了一种基于多速率采样输出反馈和幂次函数趋近律的离散滑模控制方法;理论分析表明,通过引入幂次函数可消除离散滑模控制系统的抖振;采用多速率采样技术,运用不同采样速率下的系统输出值表示系统状态,实现了仅用系统输入输出采样值完成离散滑模控制器的设计,减轻了控制系统设计的复杂性;仿真结果表明,控制器的输出、切换函数、系统的输出均不存在抖振现象,而且控制系统表现出了良好的动态特性。