非线性载波控制PFC电路研究

阐述了一种非线性载波(Nonlinear-carrier)控制的PFC电路,该电路与传统单级功率因数校正电路相比不再需要输入电压、电流采样以及复杂的模拟乘法器和电流误差放大器电路。非线性载波(NLC)控制理论基于对变换器元件(开关管、二极管或电感)的电流检测,并与非线性载波比较获得开关管PWM波形来实施控制。     

一种用于DC-DC变换器的斜坡补偿电路设计

峰值电流控制模式在DC-DC变换器中得到广泛应用,同时也带来了开环不稳定的问题。提出一种应用于DC-DC变换器的斜坡补偿电路。该电路将电流检测放大器的输出与斜坡信号叠加,实现了斜坡补偿。采用基于0.35μm的BCD工艺模型库,通过Cadence Spectre仿真验证,该电路可以有效地抑制次谐波振荡,提高DC-DC变换器的稳定性。     

基于Boost变换器拓扑PFC电路的建模与分析

介绍了以Boost变换器为主拓扑结构，平均电流控制模式下PFC电路的工作原理，并在准静态分析法的基础上，建立了系统的简化小信号模型。在此基础上，以闭环系统的带宽fc和相位裕量Φ为设计指标，给出了实用的闭环反馈控制器的设计方法。仿真与实验结果表明，所建立的小信号模型及控制器设计方法不仅对模拟PFC电路中补偿器RC网络中参数的设计有实用意义，而且在考虑系统延时的情况下，也适合于数字PFC电路中控制器的设计。     

峰值电流模式非理想Boost变换器建模

应用能量守恒法建立了非理想Boost变换器的小信号模型,在该电路拓扑结构的基础上引入了峰值电流模式控制,并进一步推导出含有斜坡补偿的情况下电路等效功率级的精确模型,该模型具有更高的精度;然后以峰值电流模式Boost变换器为基础,针对该电路存在的缺点设计了电压控制器补偿网络,使得补偿后的系统具有更好的稳定性,并通过MATLAB软件仿真验证了该方案的优点和利用价值.     

基于MOS分流技术的反激式DC-DC变换器的设计

电流检测是采用电流型控制方案DC-DC变换器的重要技术之一,文中在介绍了电流型PWM控制器的工作原理、特点的基础上,对检测电路进行分析,当输入电流大时,限流采样小电阻的损耗大,且难以单片集成。由此提出了解决此问题的MOS分流技术,并基于MOS分流技术设计了一种电流型反激式DC-DC变换器。该电路设计结构简单、成本低、易实现。     

无直流电压传感器的单相APFC变换器

文章对一种只检测交流输入电压而不需要检测输出直流电压的简化单相PFC变换器进行了理论分析和研究。在构建控制电路时,不需要常规PFC变换器中的输出电压传感器和输入电流传感器。PFC变换器的主电路为整流电路的直流侧接一级Boost电路。在控制电路中,使用电感L、等效负载电阻Rd等电路参数产生正弦电流波形基准,输出电压直接由控制量Kd(=Ed/Ea)来调节。通过控制,可以得到恒定的直流输出电压和与交流输入电压同相位的正弦电流波形。仿真结果证明了该变换器的可行性。     

基于LPC2214的ZVZCS-PWM全桥变换控制器的研究

针对传统ZVZCS-PWMDC／DC全桥变换器在实现滞后桥臂开关管零电流开关过程中,存在着辅助谐振电路附加损耗较大,软开关实现方式复杂,功率开关管电压应力和电流应力高等缺点,介绍了一种新型次级箝位移相控制的ZVZCSPWMDC／DC全桥变换器。文中分析了该变换器实现软开关的原理,同时设计了变换器数字控制系统,控制器采用LPC2214型ARM芯片,并通过一台实验样机验证了这种软开关变换器相关理论的正确性以及该数字控制系统的可行性。     

电流模式模糊控制Boost变换器的研究与建模

基于Boost变换器,介绍了一种新的控制方法一电流模式模糊控制。这种新的控制方法属于双环控制,外环由模糊控制器构成,内环是电流环。该控制方法不同于传统的以模糊控制器作控制环路的单环控制。这种新的控制方法结合了传统的模糊控制和电流模式控制的优点,能改善变换器系统的性能。本文建立了电流模式模糊控制的Boost变换器的小信号模型,推导了传递函数。在Matlab／Simulink环境下,做了基于传递函数的仿真和基于电路模块的仿真。仿真结果显示基于传递函数的仿真和基于电路模块的仿真结果一致,证实了本文所建立模型的正确性。     

基于Simplorer的Boost变换器非线性研究

主要研究了电流控制模式Boost变换器的非线性现象,详细推导了电路的迭代映射公式,并通过MATLAB编程计算得到混沌图,同时建立Simplorer电路仿真模型,通过电感电流波形图和相图对三种不同电路状态进行分析和比较。为变换器的分析提供了另外一种有效的方法,并揭示了Boost变换器的非线性本质,为变换器的分析、混沌控制和反控制奠定了基础。     

一种无均流外环并联DC-DC变换器的设计

设计了一种无均流外环并联DC-DC变换器,采用平均电流模式控制,通过控制最大编程电感电流,实现并联变换器的精确均流.采用小信号模型分析了并联变换器的均流误差和稳定性,电路实现了稳定的电流特性和快速的瞬态响应,具有优良的负载电流调节能力.仿真结果表明,该电路的均流误差在8‰以下,并联变换器在重载和轻载之间跳变时,1.5m...     

Nonlinear-carrier control for high-power-factor rectifiers based onup-down switching converters

In this paper, nonlinear-carrier (NLC) control is proposed for high-power-factor rectifiers based on flyback, Cuk, Sepic, and other up-down power converters operated in the continuous conduction mode (CCM). In the NLC controller, the switch duty ratio is determined by comparing a signal proportional to the integral of the switch current with a periodic nonlinear-carrier waveform. The shape of the NLC waveform is determined so that the resulting input-line current follows the input-line voltage, as required for unity power factor rectification. A simple exponential carrier waveform generator is described. Using the NLC controller, input-line voltage sensing, error amplifier in the current-shaping loop, and multiplier/divider circuitry in the voltage feedback loop are eliminated. The simple high-performance controller is well suited for integrated-circuit implementation, Results of experimental verification on a 150 W flyback rectifier are presented     

Nonlinear-carrier control for high-power-factor boost rectifiers

Novel nonlinear-carrier (NLC) controllers are proposed for high-power-factor boost rectifiers. In the NLC controllers, the switch duty ratio is determined by comparing a signal derived from the main switch current with a periodic, nonlinear carrier waveform. As a result, the average input current follows the input line voltage. The technique is suitable for boost converters operating in the continuous conduction mode. Input voltage sensing, the error amplifier in the current-shaping loop, and the multiplier/divider circuitry in the voltage feedback loop are eliminated. The current-shaping is based on switch (as opposed to inductor) current sensing. The NLC controllers offer comparable or improved performance over existing schemes, and are well suited for simple integrated-circuit implementation. Experimental verification on a 240 W rectifier is described     

Optimal controller design for a matrix converter based surface mounted PMSM drive system

This paper proposes a new control algorithm for a matrix converter permanent magnet synchronous motor (PMSM) drive system. First, a new switching strategy, which applies a backpropagation neural network to adjust a pseudo DC bus voltage, is proposed to reduce the current harmonics of the permanent magnet synchronous motor. Next, a two-degree-of-freedom controller is proposed to improve the system performance. The parameters of this controller are obtained by using a frequency-domain optimization technique. The controller design algorithm can be applied in an adjustable speed control system and a position control system to obtain good transient responses and good load disturbance rejection abilities. The controller design procedures require only algebraic computation. The implementation of this kind of controller is only possible by using a high-speed digital signal processor. In this paper, all the control loops, including current-loop, speed-loop, and position-loop, are implemented by a 32-b TMS320C40 digital signal processor. The hardware, therefore, is very simple. Several experimental results are shown to validate the theoretical analysis.     

Sensing of the time-varying angular rate for MEMS Z-axis gyroscopes

In this paper, a nonlinear estimation strategy for sensing the time-varying angular rate of a Z-axis MEMS gyroscope is presented. An off-line adaptive least-squares estimation strategy is first developed to accurately estimate the unknown model parameters. Both axes of a Z-axis MEMS gyroscope are then actively controlled utilizing an on-line controller/observer to facilitate time-varying angular rate sensing. The proposed nonlinear estimation strategy is developed based on a Lyapunov-based analysis, which proves that the time-varying angular rate experienced by the device can be estimated accurately. Two cases for angular rate are investigated which are time-varying and constant magnitudes. An adaptive controller/observer was also utilized for sensing the angular rate to investigate the performance of the proposed controller/observer. Representative numerical results are discussed to demonstrate the performance of the proposed nonlinear strategy in accurately sensing the applied angular rate. Overall, the proposed nonlinear controller/observer improves sensing the constant angular rate by 50% and the time-varying angular rate by 90% when compared with an adaptive controller/observer.     

Synthesis of dissipative nonlinear controllers for series resonantDC/DC converters

This paper describes analytical advances and practical experiences in a nonlinear controller design methodology for series resonant DC/DC converters. The control goal is to maintain the output voltage (which is the only measured variable) in the presence of large-load perturbations by varying the switching frequency. The proposed methodology utilizes large-scale, nonlinear switched, and generalized averaged models, and the resulting closed-loop system is exponentially convergent under typical operating conditions. The designer has a direct handle over the convergence rate, and the nonlinear controller requires only the usual output voltage measurements, while the load variations are estimated. The control structure allows for variations in both resistive and current loads. The dissipativity-based nonlinear controller is implemented in affordable analog circuitry and evaluated experimentally     

Hybrid fuzzy proportional-integral plus conventional derivativecontrol of linear and nonlinear systems

This paper presents a new approach toward the optimal design of a hybrid proportional-integral-derivative (PID) controller applicable for controlling linear as well as nonlinear systems using genetic algorithms (GAs). The proposed hybrid PID controller is derived by replacing the conventional PI controller by a two-input normalized linear fuzzy logic controller (FLC) and executing the conventional D controller in an incremental form. The salient features of the proposed controller are as follows: (1) the linearly defined FLC can generate nonlinear output so that high nonlinearities of complex systems can be handled; (2) only one well-defined linear fuzzy control space is required for both linear and nonlinear systems; (3) optimal tuning of the controller gains is carried out by using a GA; and (4) it is simple and easy to implement. Simulation results on a temperature control system (linear system) and a missile model (nonlinear system) demonstrate the effectiveness and robustness of the proposed controller     

Current sensorless position–flux tracking controller for induction motor drives

An innovative indirect field-oriented output feedback controller for induction motor drives is presented. This solution is based on output feedback since only speed and position of the motor shaft are measured, while current sensors are avoided. This approach is suitable for low cost applications, where the position sensor cannot be removed to guarantee accurate position tracking.The proposed method provides global asymptotic tracking of smooth position and flux references in presence of unknown constant load torque. It is based on the natural passivity of the electromagnetic part of the machine and it guarantees asymptotic decoupling of the induction motor mechanical and electrical subsystems achieving at the same time asymptotic field orientation. Lyapunov analysis and nonlinear control design have been adopted to obtain good position tracking performances and effective torque–flux decoupling. The cascaded structure of the controller allows performing a constructive tuning procedure for speed and position control loops.Results of experimental tests are presented to demonstrate the tracking and robustness features of the proposed solution.     

Active input-voltage and load-current sharing in input-series and output-parallel connected modular DC-DC converters using dynamic input-voltage reference scheme

This paper explores a new configuration for modular DC/DC converters, namely, series connection at the input, and parallel connection at the output, such that the converters share the input voltage and load current equally. This is an important step toward realizing a truly modular power system architecture, where low-power, low-voltage, building block modules can be connected in any series/parallel combination at input or at output, to realize any given system specifications. A three-loop control scheme, consisting of a common output voltage loop, individual inner current loops, and individual input voltage loops, is proposed to achieve input voltage and load current sharing. The output voltage loop provides the basic reference for inner current loops, which is modified by the respective input voltage loops. The average of converter input voltages, which is dynamically varying, is chosen as the reference for input voltage loops. This choice of reference eliminates interaction among different control loops. The input-series and output-parallel (ISOP) configuration is analyzed using the incremental negative resistance model of DC/DC converters. Based on the analysis, design methods for input voltage controller are developed. Analysis and proposed design methods are verified through simulation, and experimentally, on an ISOP system consisting of two forward converters.