共查询到18条相似文献，搜索用时 109 毫秒
1.
将计算机仿真技术应用于永磁同步电动机控制器的设计研究,根据永磁同步电动机的数学模型,结合直接转矩控制理论,以空调用永磁同步电动机为例,利用Matlab/Simulink软件,对永磁同步电动机直接转矩控制仿真建模,给出其仿真结果。 相似文献
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《实验室研究与探索》2017,(9)
针对传统异步电动机直接转矩及直接磁链控制中未考虑电动机效率的问题,提出异步电动机最大效率转矩比控制方法。此方法将定子磁链作为控制对象,并联合电动机损耗模型给出磁链在线计算方法。在线磁链计算是根据电动机的实时工况给出最佳磁链参考值,而参考值的给定依据是当前转矩下的效率最大,所以所提方法可应用于直接转矩或直接磁链控制系统中。而电动机损耗模型对参数具有依赖性,同时在线计算不利于工业应用,因此通过实验方法建立了一组特定温度下的多速域不同负载下的离线表。实验结果表明,所提出的算法具有可行性,尤其在轻载工况下效率提升明显。 相似文献
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从电机的基本物理概念出发,通过研究直流电动机转矩控制的解耦方法,揭示异步电动机磁场定向控制实现转矩解耦控制的本质;在此基础上,讨论了定子磁场定向、气隙磁场定向,转子磁场定向和自感磁场定向等四种磁场定向控制的控制方法;经过比较分析这四种磁场定向控制方法的控制方程,采进一步揭示转子磁场定向控制即矢量控制是可以直接实现异步电动机转矩解耦控制的方法. 相似文献
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直接转矩控制（DTC）借助于滞环调节器产生脉冲信号,直接对逆变器的导通状态进行最优控制,以获取转矩的高动态性能,并省去了复杂的矢量坐标变换.具有动态响应迅速,控制简单,易于实现等优点.本文采用自行设计的电压开关矢量表,建立了异步电动机直接转矩控制系统的基于MATLAB的仿真模型.仿真结果表明,所设计的直接转矩控制系统是正确的. 相似文献
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为抑制转矩脉动，以三相12/8开关磁阻电动机为例，根据相电压、相电流计算、拟合出非线性转矩特性曲线。通过转矩分配函数可直接调节各相转矩，增加转矩补偿来改善转矩下降问题；为解决PI控制器在强耦合非线性系统中效果不佳的问题，加入一种改进的模糊控制器。基于Matlab建立了开关磁阻电动机转矩分配控制系统的仿真模型，得到了转矩、转速波形。仿真结果表明，转矩分配函数显著减少转矩脉动；相比传统PI控制，模糊控制在系统参数变化的情况下具有更小的超调量和更短的调节时间。 相似文献
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针对异步电动机直接转矩控制（DTC）系统在低速时由于开关频率不稳定而引起转矩脉动较大的缺点，提出了一种预测控制方法。该方法根据转矩和定子磁链的误差来确定应该施加的参考电压矢量，最后利用空间矢量脉宽调制（SVPWM）方法来合成该矢量，这样即保证了逆变器的开关频率恒定，从而大大降低转矩脉动。仿真结果表明，在低速下定子磁链轨迹近似为圆，转矩脉动不明显。 相似文献
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研究了异步电机直接转矩控制的方法,利用MATLAB／SIMULINK仿真工具对直接转矩控制系统进行了建模和仿真．结果表明：直接转矩控制具有鲁棒性强、转矩动态响应速度快等优点． 相似文献
10.
方菁 《宁波职业技术学院学报》2010,14(2):19-22,39
针对传统的直接转矩控制中存在转矩、定子磁链波动大的问题,提出了一种结合空间矢量调制的模糊神经网络直接转矩控制方法。该方法运用模糊神经网络得到期望的任意相位空间电压矢量,再结合空间矢量调制直接对逆变器的开关状态进行控制,以达到减小转矩、定子磁链波动的目的。最后以TMS320F240为核心搭建了直接转矩控制系统,通过采集实验数据分析结果表明,直接转矩控制系统与传统的直接转矩控制系统相比,磁链和转矩波动明显减少,并且保持了转矩和速度的响应速度。 相似文献
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异步电机按定子磁链定向的转矩连续控制 总被引：5，自引：0，他引：5
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This paper presents an investigation of inverter fault-tolerant operation for a permanent magnet synchronous motor （PMSM） direct torque control （DTC） system under various inverter faults. The performance of a faulty standard 6-switch inverter driven PMSM DTC system is analyzed. To avoid the loss or even disaster caused by the inverter faults, a topology-modified inverter with fault-tolerant capability is introduced, which is reconfigured as a 3-phase 4-switch inverter. The modeling of the 4-switch inverter is then analyzed and a novel DTC strategy with a unique nonlinear perpendicular flux observer and feedback compensation scheme is proposed for obtaining a continuous, disturbance-flee drive system. The simulation and experimental results demonstrate that the proposed inverter fault-tolerant PMSM DTC system is able to operate stably and continuously with acceptable static and pretty good dynamic performance. 相似文献
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电机定子电阻的变化影响了直接转矩控制系统的低速性能.定子电阻的变化具有非线性、时变性等特点,难以建立精确的数学模型,因此提出了基于小波神经网络的定子电阻线辨识的方案,该网络采用梯度下降算法训练,可用于对定子电阻进行在线的辨识.仿真实验测试结果表明该辨识器能够精确辨识定子电阻值,从而有效地改善了直接转矩控制系统的低速性能. 相似文献
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Application of direct torque control to electric screw presses for speeding up torque response and reducing starting current 总被引：1，自引：0，他引：1
Fast response and stable torque output are crucial to the performance of electric screw presses. This paper describes the design of a direct torque control （DTC） system for speeding up torque response and reducing the starting current of electric screw presses and its application to the J58K series of numerical control electric screw presses with a dual-motor drive. The DTC drive system encompasses speed control, torque reference control, and switching frequency control. Comparison of the DTC dual-AC induction motor drive with corresponding AC servo motor drive showed that for the J58K-315 electric screw press, the DTC drive system attains a higher maximum speed （786 r/min） within a shorter time （1.13 s） during a 250 nun stroke and undergoes smaller rise in temperature （42.0 ℃） in the motor after running for 2 h at a 12 min-1 strike frequency than the AC servo motor drive does （751 r/min within 1.19 s, and 50.6 ℃ rise）. Moreover, the DTC AC induction motor drive, with no need for a tachometer or position encoder to feed back the speed or position of the motor shaft, enjoys increased reliability in a strong-shock work environment. 相似文献
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乔维德 《深圳职业技术学院学报》2009,8(5):13-17
为在简化开关磁阻电机控制系统结构的同时又能使其具有较快的转矩响应速度,提出一种适用于开关磁阻电机直接转矩控制的神经网络模糊推理控制方案,用神经网络定子磁链观测器取代传统的定子磁链观测器,采用模糊控制算法设计逆变器开关状态选择器,利用MATLAB对系统2种不同控制方法的仿真实验结果进行比较．通过比较发现,本文的控制方法转矩、转速、磁链响应快、脉动小,具有优良的稳定跟踪性能和动态响应。 相似文献
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Giusti M Melle G Fenocchio M Mortara L Cecoli F Caorsi V Ferone D Minuto F Rasore E 《Journal of Zhejiang University. Science. B》2011,12(3):163-173
Differentiated thyroid carcinoma (DTC) generally has a favorable outcome. Thyroid disease, treatments, stress, and comorbidity
can compromise health-related quality of life (QoL) and indirectly weigh upon the outcome. From 2004 to 2008, we evaluated
QoL longitudinally in 128 DTC subjects. During scheduled examinations, subjects were asked to undergo a semi-structured psychiatric
interview and five rated inventories. The same examination was conducted in 219 subjects after surgery for benign thyroid
pathology. Low scores represent a better QoL. DTC and control subjects were similar in terms of age, male/female ratio, concomitant
psychopharmacological treatments, and frequency of psychiatric diseases. In DTC subjects, Billewicz scale (BS) scores showed
an increasing trend over time, especially among females. The ad hoc thyroid questionnaire (TQ) scores were similar in both
groups and did not change over time, but at the end of the study ad hoc TQ and BS were significantly related. Ad hoc TQ scores
were also related to age on entry to the study. In both male and female DTC subjects, Hamilton’s tests for anxiety (HAM-A),
but not for depression (HAM-D), showed an improving trend. At the end of the study, HAM-A and HAM-D scores were comparable
to those of the control group. HAM-A and HAM-D were both positively correlated with the stage of cancer and the time between
diagnosis and treatment. Only HAM-D correlated with age on entry to the study. Kellner symptom questionnaire (KSQ) item scores
were higher in DTC subjects than in controls. The change over time in the items including anxiety, somatization, depression,
and hostility was significant. Somatization and hostility were more significantly reduced in DTC females than in DTC males.
Hostility scores were significantly lower in DTC subjects than in controls at the end of the study. Somatization and depression
were significantly related to staging on diagnosis and age on entry to the study. Our study confirms a wide variation of illness
perception in DTC subjects, which is generally unrelated to the favorable clinical follow-up of the disease. Psychological
evaluation during long-term follow-up improved QoL scores, which reached the same levels noted in subjects with a history
of thyroid surgery for benign thyroid pathology. Our data indicate that special attention should be paid to QoL in older DTC
subjects and those with more severe staging on diagnosis. 相似文献
18.
乔维德 《金华职业技术学院学报》2010,10(3):28-32
针对感应电机直接转矩控制中存在较大转矩脉动的特点,提出基于神经网络与模糊逻辑的感应电机直接转矩控制策略,用训练好的神经网络建立定子磁链观测器,将模糊控制算法引入逆变器状态开关选择器,通过对转矩误差、定子磁链误差和磁链位置角的模糊分级来实现逆变器开关的分级控制。仿真及实验结果表明,与常规DTC相比,该控制方法转矩、转速、磁链响应速度快、响应脉动小,具有良好的稳态跟踪性能和优异的动态响应。 相似文献