A new controller for boost dc–dc converters based on a novel sliding surface

ABSTRACT

In this paper, two control schemes for boost converters affected by uncertainties in input voltage and load are proposed. The boost converter dynamics is redefined in terms of new state variables to facilitate the use of a disturbance observer that can estimate matched and unmatched disturbances. A sliding surface, which is new in the context of boost converters, is proposed to enable tracking and regulation of output voltage without requiring measurement of input voltage and load current. The stability of the overall system including the disturbance observer, the sliding variable and the output is proved. The performance of the schemes is assessed for regulation of output voltage and tracking of reference voltage by simulation as well as experimentation in which various types of uncertainties and various types of reference voltages are considered.     

A nonlinearity compensation method for a matrix converter drive

This paper presents a new method to compensate the nonlinearities for matrix converter drives. The nonlinearities of matrix converter drives such as commutation delay, turn-on and turn-off time of the switching devices, and on-state switching device voltage drop is corrected by a new matrix converter model using the direction of current. The proposed method does not need any additional hardware or complicated software and it is easy to realize by applying the algorithm to the conventional vector control. The proposed compensation method is applied for high-performance induction motor drives using a 3-kW matrix converter system without a speed sensor. Experimental results show the proposed method provides good compensating characteristics.     

Research on a novel capacitor clamped multilevel matrix converter

A new multilevel matrix converter that can be applied to medium or high voltage ac drives is presented to alleviate harmonic components in the output voltage. The proposed converter contains six flying capacitors to balance the voltage distribution of series connection bidirectional switch modules and provide middle voltage levels. Stable flying capacitors voltage must be maintained to facilitate the operation of the converter. When the converter is working, the voltage of flying capacitors can be controlled by swapping two switching modes with opposite charging current corresponding to each middle voltage levels. A simple output voltage vector synthesis method is described and utilized. The operation and commutation strategies are discussed. Simulations and experiments are carried out to validate the proposed converter. Comparisons are made between proposed converter and conventional matrix converter.     

基于多重化滑模观测器的永磁直驱风力发电系统控制研究

本文选择可独立控制电机侧变换器和网侧变换器的PWM变换器作为永磁直驱风力发电系统的电能变换器,对电机侧、网侧变换器控制策略进行了阐述。电机侧采用多重化滑模观测器估算转子位置,有效抑制了抖振现象,使电机侧控制更加可靠。网侧控制采用电压外环电流内环的双闭环控制策略,可进行电能双向流动,对解耦控制进行了阐述,使系统可以更好的控制输出电能的品质。     

Control of Single-Phase-to-Three-Phase AC/DC/AC PWM Converters for Induction Motor Drives

This paper proposes a novel control scheme of single-phase-to-three-phase pulsewidth-modulation (PWM) converters for low-power three-phase induction motor drives, where a single-phase half-bridge PWM rectifier and a two-leg inverter are used. With this converter topology, the number of switching devices is reduced to six from ten in the case of full-bridge rectifier and three-leg inverter systems. In addition, the source voltage sensor is eliminated with a state observer, which controls the deviation between the model current and the system current to be zero. A simple scalar voltage modulation method is used for a two-leg inverter, and a new technique to eliminate the effect of the dc-link voltage ripple on the inverter output current is proposed. Although the converter topology itself is of lower cost than the conventional one, it retains the same functions such as sinusoidal input current, unity power factor, dc-link voltage control, bidirectional power flow, and variable-voltage and variable-frequency output voltage. The experimental results for the V/f control of 3-hp induction motor drives controlled by a digital signal processor TMS320C31 chip have verified the effectiveness of the proposed scheme     

新型矩阵式变频器在变频电梯中的应用

因为变频电梯在运行时,变频器输出存在大量谐波,本文介绍了一种新型的功率变换器,引入了电压电流双闭环控制策略,分析了一种新型的矩阵变换器输出电压和电流的谐波成分及影响因素.通过MATLAB/SIMULINK软件进行了仿真实验.结果表明.与传统的变频器相比,矩阵变换器结合输出电压电流双闭环控制,能够有效地降低输出电压电流谐波,并能抑制输入侧谐波对输出电压电流的影响。     

基于矩阵变换器的电力电子变压器

矩阵式变换器是一种新型的交交直接变换的电源变换器,可以实现交流电诸参数(相数、相位、幅值、频率)的变换。和传统的变换器相比,它具有不需要中间直流储能环节;功率双相流动:具有优良的输入电流波形和输出电压波形;可自由控制的功率因数等优点。采用矩阵变换器的电力电子变压器省略了繁重的储能电容,省去直流环节的电容,可减小温度变化对系统的影响。因此基于变换矩阵的电力电子变压器更适合大功率系统,并且适合于在未来高温的电力变换场合。     

Combined deadbeat control of a series-parallel convertercombination used as a universal power filter

This paper presents the notion of combined control of a system of interconnected power electronic converters. The concept is demonstrated using a three-phase series-parallel active power filter as an example. The described active power filter consists of a series-parallel combination of two full bridge VSIs capable of arbitrarily controlling the input current and output voltage. The proposed control scheme treats the converter combination as a single unit and uses the inverse system model to generate deadbeat control response for both input current and output voltage. A full-order predictive state observer is used to reduce the number of sensors. Simulation results show better disturbance rejection characteristics of the proposed control when compared to the separately controlled converter scheme     

Carrier-Based Modulation Technique for Matrix Converter

This paper presents a carrier-based modulation method for a matrix converter. By using the offset voltage and changing the slope of carrier, it is possible to synthesize the sinusoidal input currents with the unity power factor and desired output voltages. The proposed method is equivalent to the so called space vector pulsewidth modulation method. The proposed method uses a new point of view to understand the matrix converter modulation method such as the voltage source inverter (VSI) modulation method. Using the proposed method, this paper presents the two-phase/three-phase modulation method and dynamic/steady-state overmodulation method for the matrix converter. These methods are well developed in the study of a VSI. By the proposed steady-state overmodulation method, it is possible to synthesize the fundamental component of output voltage to be equal to that of input voltage at the cost of some distortion of input current. The feasibility of the proposed modulation method has been verified by a computer simulation and experimental results. These results show that the proposed carrier-based modulation method can be implemented easily without any tables. It can be used for the application where a higher voltage transfer ratio is essential     

Control of the Reactive Power Supplied by a WECS Based on an Induction Generator Fed by a Matrix Converter

In this paper, a new control system to regulate the reactive power supplied by a variable-speed wind energy conversion system (WECS), based on an induction generator fed by a matrix converter (MC), is presented. The control system discussed in this paper is based on an input current observer, implemented using an estimation of the modulation matrix, and a nonlinear control loop that regulates the displacement angle at the MC input. The reactive power capability of the proposed system is also investigated. The work presented in this paper demonstrates that, for the proposed WECS, the maximum reactive power supplied to the grid is about 40% of the nominal value. Experimental results obtained from an experimental prototype are presented in this paper. The performance of the system using a wind turbine emulator and typical wind profiles is discussed in this paper.      

MPC of Switching in a Boost Converter Using a Hybrid State Model With a Sliding Mode Observer

In this paper, a model of a dc–dc (boost) converter is first expressed as a hybrid/switched/variable-structure system state model for the purpose of applying recently developed hybrid optimal control theory to control switching in a boost converter. Switching control is achieved by forming the embedded form of the hybrid state model, which enables the derivation of a control that solves for the switching function that minimizes a user-defined performance index. This approach eliminates the need to form average-value models and provides flexibility to balance competing objectives through appropriate weighting of individual terms in the performance index. Since, in practical situations, both the source voltage and the load resistance vary with time in unknown and unmeasurable ways, we introduce a sliding mode observer based on an enlarged state model which allows implicit estimation of the unknown variables. The combined optimal switching control and sliding mode observer are applied to a boost converter in which several nonidealities and losses are represented. The results of time-domain simulation and hardware experiments are used to validate and compare the response of the hybrid optimal control–sliding mode observer to that of a traditional current-mode control strategy.      

一种新型矩阵式高频链逆变器控制方法

基于拓扑解耦思想提出了一种针对矩阵式高频链逆变器的新型控制策略。根据高频逆变桥生成的高频环的极性,将矩阵变换器的拓扑解耦成两个常规的三相电压源型逆变器,从而就可将常规电压源逆变器的控制方法引入到对矩阵变换器控制当中,简化了对矩阵变换器的分析。进行了实验研究,结果表明该控制方法具有较好的控制效果。     

基于TMS320F2808的矩阵变换器的研究与实现

本文介绍了矩阵变换器的特点，重点阐述了基于32位DSP TMS320F2808的矩阵变换器的设计与实现，该系统主要由主控制器、输入电压状态检测、译码及隔离驱动、电流检测、上位机通讯等电路组成，最后给出了实验结果。结果表明该系统能输出频率、电压均可在线调节的正弦波。     

矩阵式变换器空间矢量过调制策略研究

针对矩阵变换器调制策略电压传输比低的问题,在深入研究矩阵式变换器空间矢量调制策的基础上,提出了一种通过改变电压调制系数提高电压传输比的空间矢量过调制策略。根据电压矢量轨迹与空间矢量六边形位置的关系,将电压空间矢量调制区域分为线性调制区和过调制区,通过改变电压调制系数,从而实现过调制策略。最后建立MATLAB/Simulink仿真,结果表明空间矢量过调制策略可以有效提高电压传输比到0.955。     

Low cost fuel cell converter system for residential power generation

The high installation cost is the major obstacle of the commercialization of the solid oxide fuel cell for distributed power generation. This paper presents a new low cost 10-kW converter system to overcome this obstacle. The proposed system consists of an isolated dc-dc converter to boost the fuel cell voltage to 400 V dc and a pulse-width modulated inverter with filter to convert the dc voltage to two split-phase 120-V ac. The dc-dc converter uses phase shifting to control power flow through a transformer with a metal oxide semiconductor field effect transistor full bridge on the low voltage side and a voltage doubler on the high voltage side. One IPM is used to realize the voltage doubler and the dc-ac inverter. Compared to the existing fuel cell converter systems, the proposed circuit has low cost, less component count, smaller size, and reduced dc-dc converter peak current. Simulation and experimental results are demonstrated.     

Experimental evaluation of ride-through capabilities for a matrixconverter under short power interruptions

The matrix converters, which are direct power electronic converters, are able to provide important benefits such as bidirectional power flow, sinusoidal input currents with adjustable displacement angle, and a great potential for size reduction. Still, two major disadvantages exist: a lower than unity voltage transfer ratio and high sensitivity to power grid disturbances. Many solutions to provide continuous operation of adjustable speed drives (ASDs) during power grid disturbances have been proposed, but they are all applied to DC-link ASD. In this paper, a new solution to provide limited ride-through operation is presented with a matrix converter using a scalar controlled induction motor for a duration of hundreds of milliseconds, without any hardware modification. During the ride-through operation, the drive is not able to develop torque or to control the motor flux. By recovering the necessary power to feed the control hardware of the matrix converter, it is able to keep the ASD operating. When normal grid conditions are reestablished, the matrix converter is able to accelerate the motor from nonzero speed and flux by initializing the modulator with the estimated frequency and the initial angle of the reference output voltage vector. The maximum duration of the ride-through operation depends on the initial motor flux, speed level, rotor time constant, load torque, and inertia. This method is verified on a laboratory setup with a matrix converter     

直流微电网双向AC/DC变换器鲁棒前馈控制策略研究

针对双向AC/DC功率变换器在直流微电网母线电压稳定性方面的问题,文中提出了一种结合LESO和滑模理论的前馈鲁棒控制策略。通过建立直流微电网三相AC/DC双向功率变换器的动态数学模型,架构了三阶线性扩张状态观测器,并将三阶LESO的观测值用于滑模控制器的设计。该控制策略能够在不需要额外电流传感器的情况下实现前馈控制,并确保系统具有良好的动态性能。该策略还能够有效降低滑模控制的实现难度,提高系统的鲁棒性。仿真分析验证了文中所提控制策略的有效性。     

A transient enhanced DVS DC–DC converter based on state trajectory analysis

Dynamic voltage scaling (DVS) can effectively reduce energy consumption by dynamically varying the supply voltage of the system accordingly to the clock frequency. A new DVS-enabled DC–DC converter is presented in this paper. State trajectory is employed to analyze the transient features of PWM and PFM Buck converters. A novel transient enhancement circuit is designed to improve the transient response of the DVS-enabled Buck converter. To further expand the output voltage range of the converter, a current-starved voltage controlled delay line is proposed in the controller of DC–DC converter to obtain an ultra low voltage of 0.5 V. When the input voltage is 3.3 V, the output voltage of the converter can be dynamically regulated from 0.5 to 2.0 V. The output voltage tracking speed is less than 7.5 μs/V and the recovery speed is 33 μs/A for a load current step from 0.6 to 0.2 A at output voltage of 0.5 V. The chip area is 1.75 mm × 1.33 mm in a 0.18 μm standard CMOS process.     

NPC三电平逆变器中点电位观测器设计及控制

针对中点嵌位型（Neutral Point Clamp,NPC）三电平逆变器的中点电压波动会引起输出电压失真的问题,设计了一种观测器对中点电压波动进行观测,并根据观测结果设计了模糊PI控制器对其进行控制。首先建立了NPC三电平逆变器的数学模型,通过对直流侧电容电压的数学模型进行分析,将逆变器的中点电位不平衡问题近似为系统存在扰动下的误差估计;其次,根据模糊逻辑规则定义了新的误差变量,设计了模糊PI控制器,对中点电位波动问题进行控制;最后通过仿真和实验结果表明：设计的观测器可有效完成对中点电位的准确观测,利用模糊PI控制器实现了对中点电压波动的有效控制。     

矩阵式变换器在变速恒频风电系统中的应用

本文首先对9开关矩阵变换器的工作原理以及控制方法进行分析,然后建立了矩阵变换器在d-q坐标系下的数学模型和矩阵式变换器实现变速恒频风力发电功率转换控制结构,并对矩阵式变换器实现变速恒频风电功率转换控制结构进行仿真,结果表明矩阵式变换器应用于变速恒频风力发电系统实现功率转换是可行的。