基于改进型M2PC控制方法的MC-PMSM控制系统

针对传统的模型预测控制(model predictive control,MPC)方法、调制模型预测控制(modulation MPC,M2PC)存在的问题,提出改进型M2PC方法,并用于矩阵变换器(matrix converter,MC)-永磁同步电机(permanent magnet synchronous motor,PMSM)系统控制。首先,给出了MC-PMSM的拓扑结构,分析了基于传统MPC、M2PC方法的MC-PMSM控制系统及其存在的问题;接着,提出了基于改进型M2PC方法,该方法不但能够固定开关频率,还能降低计算量和改善波形质量;最后,在RTDS平台上对MC-PMSM系统采用改进型M2PC方法进行仿真,并与采用传统的MPC、M2PC方法进行了比较。结果表明,所提改进型M2PC方法的控制性能优于传统的MPC、M2PC方法。

MMMC两侧电流基于Lyapunov函数的控制策略

分频传输系统(fractional frequency transmission system,FFTS)是一种海上风电电能传输方案,FFTS中最为关键的装置为大功率AC/AC变换器,而模块化多电平矩阵变换器(modular multilevel matrix converter,MMMC)是一种高电压、大功率AC/AC变换器。针对MMMC输入输出两侧的电流控制,目前一般都采用传统PI控制,其控制参数多且控制效果不理想,而基于Lyapunov函数的控制策略的控制器数量、控制复杂程度和效果都优于PI控制,因此提出了MMMC输入输出两侧电流的Lyapunov函数控制策略。根据MMMC的拓扑结构,推导出MMMC输入输出两侧电流解耦模型,再结合Lyapunov函数控制理论,推导出MMMC输入输出两侧电流的Lyapunov函数控制的数学模型,证明了所提控制具有全局渐进稳定性,讨论了Lyapunov函数控制的不精确以及参数选择问题。最后在MATLAB仿真平台上针对MMMC输入输出两侧电流控制采用所提控制策略和传统控制策略分别在不同工况下进行实验比较,仿真结果验证了所提控制策的正确性与优越性。

基于动态开关表的TLDMC-PMSM零共模电压直接转矩控制

针对三电平直接矩阵变换器-永磁同步电机系统采用直接转矩控制(TLDMC-PMSM-DTC)时出现高共模电压的问题,提出基于动态开关表的TLDMC-PMSM零共模电压直接转矩控制方法。TLDMC的部分旋转矢量共模电压为零,该方法利用这部分旋转矢量去构建DTC的开关表,但是旋转矢量的分布随输入电压相位的变化而变化,这会导致控制结构的复杂度变高,因此此控制算法通过高维开关表来实现TLDMC-PMSM的零共模电压。但是由于所用旋转矢量数目少并且选择的矢量误差大,从而导致电机的转速和转矩脉动大,该文在此基础上,引入动态的旋转矢量和零矢量去构建动态开关表来解决脉动大的问题。仿真和实验结果表明,该方法在保证动态响应能力快、电机的转速和转矩脉动小的基础上,实现了TLDMC-PMSM系统的零共模电压和安全稳定运行。

基于MCS-51的高精度信号发生器设计与仿真验证

本文设计的信号发生器以MCS-51单片机为核心,辅助以按键电路、显示电路、数模转换电路,能够发出三角波、正弦波、方波、锯齿波四种波形。通过引入DAC0823芯片,将数字量和模拟量进行转换,使得信号发生器发出的波形的误差和噪声干扰更小,并简化了滤波过程。仿真过程中通过软件程序控制硬件电路,利用Keil仿真平台的元器件仿真功能和程序编辑功能将程序搭建好,然后一同放入Proteus仿真平台中,通过后者的元器件选择和参数调节功能将信号发生器的主控电路搭建完成。最后,利用模拟示波器得到了满足设计要求的波形,验证了信号发生器的性能。

基于调制系数最优法的TLDMC-PMSM新型直接转矩控制

针对矩阵变换器永磁同步电机系统(MC-PMSM)直接转矩控制方法出现的转矩磁链脉动大、幅值失调、系统鲁棒性弱等问题,提出了一种基于调制系数最优法的三电平直接矩阵变换器永磁同步电机(TLDMCPMSM)新型直接转矩控制方法。首先描述了MC-PMSM直接转矩控制系统的原理;其次用三电平直接矩阵变换器替换两电平矩阵变换器,转速环通过复叠式螺旋滑模控制、转矩磁链环通过超螺旋滑模直接转矩控制替换传统的比例积分控制,并且引入调制系数最优法来抑制电机转矩波动逐渐增大,进而实现对永磁同步电机的精确控制;最后通过MATLAB/Simulink仿真软件和硬件实验验证所提方法的可行性与优越性。

Model Predictive Control-Based Direct Torque Control for Matrix Converter-Fed Induction Motor with Reduced Torque Ripple

To reduce the torque ripple in motors resulting from the use of conventional direct torque control(DTC),a model predictive control(MPC)-based DTC strategy for a direct matrix converter-fed induction motor is proposed in this paper.Two new look-up tables are proposed,these are derived on the basis of the control of the electromagnetic torque and stator flux using all the feasible voltage vectors and their associated switching states.Finite control set model predictive control(FCS-MPC)has then been adopted to select the optimal switching state that minimizes the cost function related to the electromagnetic torque.Finally,the experimental results are shown to verify the reduced torque ripple performance of the proposed MPC-based DTC method.

Investigation of matrix effects in the MC-ICP-MS induced by Nb, W, and Cu: Isotopic case studies of iron and copper

Some elements normally occur at trace levels while the majority of natural geological materials may be exceedingly enriched in some special cases, such as the Bayan Obo ore deposit where REE and Nb are extremely enriched. These elements may not be removed completely during purification. Therefore, matrix effects will be caused during stable isotope ratio measurement in the MC-ICP-MS. Experiments have shown that the established methods of chromatographic separation of Cu, Fe, and Zn using AG MP-1 Anion Exchange Resin cannot make ef-fective separation of Nb, W, and Cu from Fe using 20 mL 6 M HCl. It is also observed that the elution curves of W and Cu overlap at working conditions and thus W is present in measurable amounts in some sample solutions. Matrix effects in the MC-ICP-MS induced by Nb, W, and Cu during Fe isotope ratio measurements and by W during Cu isotope ratio measurements were thus investigated by examining their changes in delta values between doped and undoped standards. The results show that the effects of the matrix elements Nb, W, or Cu on Fe isotope ratio measurements are minimal in the case of m(Nb)/m(Fe)<0.005, m(W)/m(Fe)<0.01, or m(Cu)/m(Fe)<0.6. This finding, combined with the extremely low levels of W and Cu, and the fact that nearly 90% of Nb can be removed during purification, demonstrates that the methods of chromatographic separation of Fe established before are suitable for Bayan Obo ore samples and that the methods can be simplified when Cu elution is unnecessary. The effects of the matrix element W on Cu isotope determinations are minimal in the case of m(W)/m(Cu)<0.7. Therefore, W exerts no significant effect on the measurements of Cu isotopes for the majority of natural geological materials.

Advance in Matrix Effect Study of LA-MC-ICPMS U-Pb Dating on U-Bearing Oxide Minerals

Objective With the development of analytic technologies, in-situ dating on U-bearing oxide minerals （e.g., cassiterite, rutile and baddeleyite） has been widely used in geological chronological researches and has attracted remarkable attention to explore evolution of the earth and obtain age information of various geological processes. Matrix effect related studies are especially important during in-situ U- Pb dating based on Laser Ablation Multiple Collector Inductively Coupled Plasma Mass Spectrometry （LA-MC- ICPMS）. However, to our knowledge, only few thorough and systematical matrix effect study of U-bearing oxide minerals has been reported. In this study, we systematically analyzed the matrix effect of U-bearing oxide minerals in order to take place the standards which are difficult to prepare with available standards.

AC/DC Matrix Converters for V2G Applications

由于当前V2G系统中普遍采用的电压型脉宽调制（pulse width modulation,PWM）整流方案中所存在的蓄电池电压匹配、功率体积比及系统效率问题,提出一种采用AC/DC矩阵变换器的解决方案。针对经典电流空间矢量调制策略中充电电流纹波较大的缺点,提出一种在全输出范围内减小充电电流纹波的分段优化调制策略,并深入对比分析这两种调制策略下充电电流纹波的大小。仿真和实验结果表明,所提分段优化调制策略的正确性和可行性。

基于投切状态矩阵的MMC系统电容电压均衡策略

为了奠定模块化多电平换流器(modular multilevel converter,MMC)自平衡的理论依据,构建了MMC状态空间模型,证明了MMC电容电压的一致渐进稳定性。研究了MMC电容电压非均衡状态下的静态工作点,揭示了投切状态矩阵的秩和MMC电容电压静态工作点之间的关联。基于投切状态矩阵自平衡理论,针对控制频率较低或子模块数量较多时轮换速度慢的问题,提出了一种基于投切状态矩阵分组轮换的电容电压均衡控制策略,能够有效降低电容电压的波动率。最后,在Matlab/Simulink中搭建了MMC电磁暂态仿真模型,验证了所证结论的正确性和所提方法的有效性。

High Performance Control of Matrix Converter Fed Induction Motor Drive System

Matrix converter fed motor drive is superior to pulse width modulation inverter drives since it not only provides bi-directional power flow,sinusoidal input/output currents,unity input power factor,but also allows a compact design due to the lack of DC-link capacitors for energy storage.In this paper,model and control of matrix converter fed induction motor drive system are analyzed.A combined control strategy is simplified and improved,which realizes space vector pulse width modulation of matrix converter and rotor flux oriented vector control technique for induction motor drive simultaneously.This control strategy combines the advantages of matrix converter with the good drive performance of vector control technique.Experimental results demonstrate the feasibility and effectiveness of the proposed control strategy.

PI and RST Control Design and Comparison for Matrix Converters Using Venturini Modulation Strategy

This paper presents a thorough design and comparative study of two popular control techniques, i.e., classical Proportional Integral (PI) and RST, for Matrix Converters (MCs) in terms of tracking the reference and robustness. The output signal of MCs is directly affected by unbalanced grid voltage. Some research works have attempted to overcome this problem with PI control. However, this technique is known to offer lower performance when it is used in complex and nonlinear systems. On the other hand, RST control offers better performance, even in case of highly nonlinear systems. Therefore, the RST can achieve better performance to overcome the limitation of PI control of nonlinear systems. In this paper, a RST control method is proposed as output current controller to improve the performance of the MC powered by unbalanced grid voltage. The overall operating principle, Venturini modulation strategy of MC, PI control and characteristics of RST are presented.

Research of matrix converter based on asymmetric regular sampling method SPWM control strategy

Based on the topological analysis of three-phase matrix AC to AC conversion circuit, an AC to AC nine-switch matrix isequivalent to rectification part and conversion part. The Matrix converter can be viewed as AC-DC-AC converter, the asymmetricregular sampling method SPWM(Sine Pulse Width Modulation) is studied and applied in the three-phase matrix AC to AC converter,Based on Matlab/simulink the simulation of the matrix converter with such strategy is carried out. Inductive load simulation is carriedout on the matrix converter prototype. The simulation results verify the workability of the asymmetric regular sampling method SPWMstrategy for matrix converter.

Control of Doubly Fed Induction Generator Supplied via Matrix Converter for Wind Energy Conversion System

The present paper deals with the modeling and control of Wind Energy Conversion System WECS based Doubly Fed Induction Generator DFIG using the slip energy recovery principle. The proposed drive system uses a Matrix Converter (MC) to transfer the slip energy of the rotor into the mains instead of using cascaded ac-dc-ac converter whilst the stator side is fixed to the grid. Operation at both sub-synchronous and super-synchronous regions is possible with the proposed drive system. The different level control strategies for maximum power point tracking and active-reactive power are discussed. Simulation results of the proposed doubly fed induction generator drive system show the good performance of the control system strategy for both transient and steadystate conditions.

Three Phase Dual Input Direct Matrix Converter for Integration of Two AC Sources from Wind Turbines

This project proposes a novel dual-input matrix converter (DIMC) which is used to integrate the output of the wind energy to a power grid. The proposed matrix converter is developed based on the traditional indirect matrix converter under reverse power flow operation mode, but with its six-switch voltage source converter replaced by a nine-switch configuration followed by the current source inverter (CSI). Matrix electric power conversion topologies and their switch functions are flexible and are used for specific applications. With the additional three switches, the proposed DIMC can provide six input terminals, which make it possible to integrate two independent AC sources from two independent wind turbines into a single grid tied power electronics interface. Commanded currents can be extracted from the two input sources to the grid. The proposed PI control and modulation schemes guaranteed sinusoidal input and output waveforms as well as reduced THD. The simulation results are provided to validate the effectiveness of the proposed control and modulation schemes for the proposed converter.

一种高频链的IMC九开关逆变器

提出一种用于双电机传动系统的高频链(HFL)间接矩阵变换器(IMC)九开关逆变器拓扑,解决了传统IMC九开关逆变器电压传输比低的问题,同时具有功率密度高、传输损耗低、能够实现输入输出级电气隔离的优点。提出了用于HFL IMC九开关逆变器的半周期双极性空间矢量调制策略和双逆变器输出的分层控制策略,实现了零电流换流的同时也扩大了变换器的应用范围。仿真结果验证了控制策略的正确性和有效性。

Short-circuit fault analysis and isolation strategy for matrix converters

The behavior of matrix converter(MC) drive systems under the condition of MC short-circuit faults is comprehensively investigated. Two isolation strategies using semiconductors and high speed fuses(HSFs) for MC short-circuit faults are examined and their performances are compared. The behavior of MC drive systems during the fuse action time under different operating conditions is explored. The feasibility of fault-tolerant operation during the fuse action time is also studied. The basic selection laws for the HSFs and the requirements for the passive components of the MC drive system from the point view of short-circuit faults are also discussed. Simulation results are used to demonstrate the feasibility of the proposed isolation strategies.

Hybrid Control Strategy for Matrix Converter Fed Wind Energy Conversion System

In this paper, a hybrid control strategy for a matrix converter fed wind energy conversion system is presented. Since the wind speed may vary, output parameters like power, frequency and voltage may fluctuate. Hence it is necessary to design a system that regulates output parameters, such as voltage and frequency, and thereby provides a constant voltage and frequency output from the wind energy conversion system. Matrix converter is used in the proposed solution as the main power conditioner as a more efficient alternative when compared to traditional back-back converter structure. To control the output voltage, a vector modulation based refined control structure is used. A power tracker is included to maximize the mechanical output power of the turbine. Over current protection and clamp circuit input protection have been introduced to protect the system from over current. It reduces the spikes generated at the output of the converter. The designed system is capable of supplying an output voltage of constant frequency and amplitude within the expected ranges of input during the operation. The matrix converter control using direct modulation method, modified Venturini modulation method and vector modulation method was simulated, the results were compared and it was inferred that vector modulation method was superior to the other two methods. With the proposed technique, voltage transfer ratio and harmonic profile have been improved compared to the other two modulation techniques. The behaviour of the system is corroborated by MATLAB Simulink, and hardware is realized using an FPGA controller. Experimental results are found to be matching with the simulation results.

Model Predictive Control Circuit of the Current Source Matrix Converter

In this paper, a new predictive control strategy for current source matrix converter (CSMC) is presented. Proposed predictive control strategy allows for creating output voltages with boost type voltage transfer ratio and desired frequency. The description of predictive control circuit of the CSMC is presented. Furthermore the simulation test results to confirm functionality of the proposed control strategy and converter properties under this strategy are shown.