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无交流电压传感器PWM整流器启动性能改善 总被引:2,自引:1,他引:1
提出一种基于虚拟磁链的PWM整流器无交流电压传感器运行启动性能的改善方法.通过采用带有积分限幅反馈环节的积分器代替不定积分器进行虚拟磁链观测,解决了传统方法存在的初始值选取和观测结果存在幅值和相位误差等问题.对基于改进方法的虚拟磁链直接功率控制PWM整流器进行了实验验证,实验结果证明了该改进方法的正确性和可行性. 相似文献
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针对无电网电压传感器的PWM整流器虚拟磁链估算中存在的直流漂移问题,研究了一种新的磁链估算方法,即在积分后面加入改进的二阶广义积分环节,良好地解决了直流漂移问题。采用电压外环PI控制,电流内环PR控制,简化了繁琐的坐标变化和解耦环节,仿真结果证明了该方案的可行性。 相似文献
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针对非恒值磁链幅值给定的永磁同步电动机基于空间电压矢量调制的直接转矩控制(SVM-DTC)系统,传统的第二类改进型积分器不能对磁链进行准确观测,且电动机输出性能差。提出了一种变限幅的改进型积分器,实现在非恒值磁链幅值给定SVM-DTC系统的磁链准确观测,电动机运行稳定并能提高功率因数。 相似文献
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针对永磁同步电动机(PMSM)直接转矩控制(DTC)中磁链和转矩脉动问题,提出了一种新的基于定子磁链自适应预测的直接转矩控制方法.采用转子位置和定子电流预测下一控制周期定子的磁链,通过预测和估算定子磁链的偏差计算出下一个控制周期所施加的参考电压空间矢量;采用对称七段式SVM技术调制该电压,实现每个周期对磁链和转矩误差的补偿,从根本上抑制磁链和转矩的脉动.理论分析和仿真结果表明,该方法与传统直接转矩控制相比,能显著抑制磁链和转矩脉动,且具有良好的动静态性能.研究具有一定实际应用价值. 相似文献
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无交流电压传感器并网逆变器的控制策略及其改进 总被引:1,自引:1,他引:0
将基于虚拟磁链的直接功率控制策略用于并网逆变器的控制.详细推导了虚拟磁链与瞬时功率的表达式,在无需检测网侧交流电压的前提下即可获得并网功率的瞬时值,进而取消了交流电压传感器.通过对并网功率的有功和无功成分进行直接独立控制,省去了旋转坐标变换以及电流闭环控制等复杂算法.采用带有饱和限幅反馈环节的积分器代替不定积分器进行虚拟磁链观测,解决了因传统观测方法存在功率计算偏差而造成系统效率降低、动态响应性能较差等问题.对所提出的改进观测方法及基于改进虚拟磁链直接功率控制策略的并网逆变器进行仿真和实验,结果证明了所提方法的正确性和可行性. 相似文献
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Hava A.M. Seung-Ki Sul Kerkman R.J. Lipo T.A. 《Industry Applications, IEEE Transactions on》1999,35(4):896-907
In this paper, the dynamic overmodulation characteristics of current-regulated carrier-based high-performance pulsewidth modulation (PWM) voltage-source inverter drives are investigated. Dynamic and steady-state overmodulation operating modes are clearly distinguished, and the requirements for obtaining high performance in each mode are shown to be significantly different. Dynamic overmodulation characteristics of the modern triangle intersection PWM methods are modeled and shown to be unique for each method. The study reveals space-vector PWM (SVPWM) exhibits a minimum voltage magnitude error characteristic. It also indicates all the advanced triangle intersection PWM methods, including SVPWM, have limited dynamic overmodulation performance. To enhance the performance, an algorithm with superior performance is adapted from the direct digital PWM approach. Detailed induction motor drive simulations and experimental results illustrate the characteristics of modern triangle intersection PWM methods and the performance gained with the new dynamic overmodulation algorithm 相似文献
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研究了电动车用内置式永磁同步电机的控制策略,提出了超前角弱磁控制与空间矢量脉宽调制(SVPWM)过调制结合的控制系统。超前角弱磁控制使用转速、电流和电压的3个闭环控制,电机端电压与直流侧电压组成电压控制环,产生电机弱磁的电流超前角直接给定交直轴电流。SVPWM过调制算法可以有效提高逆变器输出电压基波幅值,电机使用弱磁控制方式达到最大转速后使逆变器进入过调制状态,最大限度扩大转速范围。对该控制系统进行了仿真研究,仿真结果证明了理论分析的正确性和可行性。 相似文献
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针对异步电机基于转子磁链模型参考自适应(MRAS)速度观测器中的积分直流偏置和PI自适应率参数不能在线修正的问题,将转子磁链的电压模型进行改进,并提出一种自适应线性神经元(ADALINE)速度观测器。通过一阶惯性环节代替了电压模型中的纯积分环节,消除了积分直流偏置和误差积累,利用ADALINE算法对MRAS观测器中的自适应率进行改进,实现了在中高速情况下对电机转速的准确观测。仿真结果表明,改进后的MRAS速度观测器对速度的辨识度较高,动态性能良好,验证了该控制策略的正确性与可行性。 相似文献
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A new direct torque and stator flux control method is presented for pulsewidth modulation (PWM) inverter-fed induction motors. This new strategy, called decoupled direct control (DDC), is based on a decoupling matrix that allows for the separate control of the stator flux and the torque. This method is compared to the well-known direct field-oriented control (FOC) and stator flux vector control (SFVC) methods. Two DDC-based methods are presented. The first determines the stator voltage vector such that the torque and the flux track their respective reference trajectories in one sampling time. The second sets separately the dynamic behavior of the torque and stator flux errors by the use of proportional-plus integral (PI)-type controllers. These methods take into account the full motor dynamics without the need of a coordinate transformation and reduce significantly computation requirements compared to FOC and SFVC. The two proposed strategies have been implemented experimentally and comparisons with FOC and SFVC were carried out. The obtained results show the effectiveness of the proposed PI-DDC strategy. 相似文献
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M.F. Mimouni R. Dhifaoui 《International Journal of Adaptive Control and Signal Processing》2002,16(9):653-680
This paper shows that it is possible to extend the principle of field‐oriented control (FOC) approach to a double‐star induction motor (DSIM). In the first stage, a robust variable structure current controller based on space phasor voltages PWM scheme is established. In this current controller design, only the stator currents and rotor speed sensors are used. In the second stage, the FOC method developed for DSIM is motivated by the minimization of the copper losses. The developed approach uses a loss model controller (LMC) and an adaptive rotor flux observer to compute the adequate rotor flux value minimizing the copper losses. The control variables are the stator currents or the machine input power. Compared to the constant rotor flux approach, it is proved that higher performances are achieved. However, the sensitivity of the FOC to parameter error of the machine still remains a problem. To guarantee the performance of the vector control, the stator and rotor resistances are adapted on‐line, based on the Lyapunov theory. An appropriate choice of the reference model allows building a Lyapunov function by means of which the updating law can be found. The simulation results show the satisfactory behaviour of the proposed identification algorithm. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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在电机控制中,过调制算法能够显著提高逆变器输出的电压,对提高电机转速有着重要意义。为了改善空间矢量脉宽调制对直流母线电压利用率不足的缺点,研究了基于空间矢量脉宽调制的单模式过调制算法,对输出电压基波幅值与其谐波含量进行理论分析。针对过调制区实际输出电压基波幅值与参考电压不一致这一问题,对目标调制比与给定调制比的关系作出可控性分析,作出拟合曲线并求出函数关系,最后对该过调制算法进行了仿真研究和试验验证。仿真分析和试验验证结果均证明了理论分析的正确性和可行性。 相似文献
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A high-performance generalized discontinuous PWM algorithm 总被引:1,自引:0,他引:1
In this paper, a generalized discontinuous pulsewidth modulation (GDPWM) method with superior high modulation operating range performance characteristics is developed. An algorithm which employs the conventional space-vector PWM method in the low modulation range, and the GDPWM method in the high modulation range, is established. As a result, the current waveform quality, switching losses, voltage linearity range, and the overmodulation region performance of a PWM voltage-source inverter (PWM-VSI) drive are optimized online, as opposed to conventional modulators with fixed characteristics. Due to its compactness, simplicity and superior performance, the algorithm is suitable for most high-performance PWM-VSI drive applications. This paper provides detailed performance analysis of the method and compares it to the other methods. The experimental results verify the superiority of this algorithm to the conventional PWM methods 相似文献