共查询到20条相似文献，搜索用时 265 毫秒
1.
ＩＮＴＲＯＤＵＣＴＩＯＮＶａｒｉｏｕｓｅｌｅｃｔｒｏ ｈｙｄｒａｕｌｉｃｖａｌｖｅｓａｒｅｗｉｄｅｌｙｕｓｅｄｉｎｉｎｄｕｓｔｒｙ.Ｓｌｉｄｅｖａｌｖｅｏｒｓｐｏｏｌ,ａｓａｂａｓｉｃｓｔｒｕｃｔｕｒｅ,ｐｌａｙｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｖａｒｉｏｕｓｅｌｅｃｔｒｏ ｈｙｄｒａｕｌｉｃｃｏｎｖｅｒｔｅｒｓｙｓｔｅｍｓ,ｉｎｃｌｕｄｉｎｇｓｅｒｖｏｖａｌｖｅ,ｐｒｏｐｏｒｔｉｏｎａｌｖａｌｖｅａｎｄｏｎ ｏｆｆｖａｌｖｅｓｙｓｔｅｍｓ.Ｓｐｏｏｌｆａｉｌｕｒｅｃａｎｖｅｒｙｐｏｓｓｉｂｌｙｐｕｔ… 相似文献
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ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｔｈｔｈｅｅｍｅｒｇｅｎｃｅｏｆＫｎｏｗｌｅｄｇｅＥｃｏｎｏｍｙａｎｄｔｈｅｒｅｆｏｒｍｏｆｔｈｅｓｃｉｅｎｃｅａｎｄｔｅｃｈｎｏｌｏｇｙｓｙｓ ｔｅｍ ,ｆｒｏｍｔｈｅｂｅｇｉｎｎｉｎｇｏｆｉｔｓｉｎｔｒｏｄｕｃｔｉｏｎｉｎＣｈｉｎａ,ｖｅｎｔｕｒｅｃａｐｉｔａｌｈａｓｂｅｅｎｔａｋｅｎｓｅｒｉｏｕｓｌｙｂｙｏｕｒｇｏｖｅｒｎｍｅｎｔ.ＴｈｅｌａｔｅｓｔｓｕｒｖｅｙｂｙｔｈｅＶｅｎｔｕｒｅＣａｐｉｔａｌＲｅｓｅａｒｃｈＴｅａｍ (ＶＣＲＴ)ｏｆｔｈｅＭｉｎｉｓｔｒｙｏｆＳｃ… 相似文献
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ＳＯＦＴＷＡＲＥＥＶＯＬＵＴＩＯＮＳｏｆｔｗａｒｅｅｖｏｌｕｔｉｏｎｈａｓｂｅｅｎａｄｄｒｅｓｓｅｄｆｒｏｍｍａｎｙｖｉｅｗｐｏｉｎｔｓ .Ｔｈｅｓｅｉｎｃｌｕｄｅｍａｎａｇｅｍｅｎｔｉｓ ｓｕｅｓｓｕｃｈａｓｗｈｉｃｈｐａｒｔｓｏｆａｓｙｓｔｅｍｓｈｏｕｌｄｂｅｒｅｂｕｉｌｔ,ｃｏｎｆｉｇｕｒａｔｉｏｎｉｓｓｕｅｓｓｕｃｈａｓｋｅｅｐｉｎｇｔｒａｃｋｏｆｍａｎｙｖｅｒｓｉｏｎｓｏｆｔｈｅｓａｍｅｓｙｓｔｅｍ ,ｔｅｓｔ ｉｎｇｉｓｓｕｅｓｓｕｃｈａｓｄｅｔｅｒｍｉｎｉｎｇｗｈｉｃｈｔｅｓｔｃａｓｅｓ… 相似文献
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Donghong 《上海大学学报(英文版)》1999,(2)
ＮｏｍｅｎｃｌａｔｕｒｅＬｅｔＶａｎｄＺｂｅｔｗｏｒｅａｌＣ∞ｍａｎｉｆｏｌｄｓ,ｄｉｍ．Ｖ＝ｎ≥２,ｄｉｍ．Ｚ＝ｍａｎｄＤＪｋ（Ｖ,Ｚ）ｉｓａｓｙｓｔｅｍｏｆｋ０ｔｈｏｒｄｅｒｐａｒｔｉａｌｄｉｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｓ．Ｊｋ（Ｖ,Ｚ... 相似文献
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SHORT CIRCUIT CURRENT LIMITER IN AC NETWORK 总被引：13，自引：0，他引：13
ＩＮＴＲＯＤＵＣＴＩＯＮＳｈｏｒｔｃｉｒｃｕｉｔｉｎｐｏｗｅｒｓｙｓｔｅｍｓｉｓａｓｅｒｉｏｕｓｆａｕｌｔ,ｗｈｉｃｈｍａｙｄａｍａｇｅｔｈｅｅｑｕｉｐｍｅｎｔｉｎｔｈｅｓｙｓｔｅｍ .Ｉｔｒｅｑｕｉｒｅｓｔｈｅｐｒｏｔｅｃｔｉｏｎｓｙｓｔｅｍｔｏｓｗｉｔｃｈｏｆｆｔｈｅｖｅｒｙｈｉｇｈｌｅｖｅｌｏｆｆａｕｌｔｃｕｒｒｅｎｔ.Ｔｈｅｔｒａｄｉｔｉｏｎａｌｍｅｔｈｏｄｔｏｌｉｍｉｔｔｈｅｓｈｏｒｔｃｉｒｃｕｉｔｃｕｒｒｅｎｔｌｅｖｅｌｉｓｔｏｓｅｒｉａｌｌｙｃｏｎｎｅｃｔａｌｉｍｉｔｉｎｇｒｅ ａｃｔ… 相似文献
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ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅＣｈｉｎａｓｔａｒｔｅｄｅｃｏｎｏｍｉｃｓｙｓｔｅｍｒｅｆｏｒｍｉｎ 1 978,ｍｏｎｅｔａｒｙｐｏｌｉｃｙｈａｓｂｅｅｎｆｕｌｌｙｕｓｅｄｔｏａｄｊｕｓｔｔｈｅｍａｃｒｏｅｃｏｎｏｍｙａｎｄａｃｈｉｅｖｅｄｇｏｏｄｅｆ ｆｅｃｔｓ.Ｔｉｇｈｔｍｏｎｅｔａｒｙｐｏｌｉｃｙｃｏｎｔｒｏｌｓｉｎｆｌａｔｉｏｎｅｆ ｆｅｃｔｉｖｅｌｙｗｈｉｌｅｅｘｐａｎｓｉｖｅｍｏｎｅｔａｒｙｐｏｌｉｃｙｓｔｉｍｕ ｌａｔｅｓｅｃｏｎｏｍｉｃｄｅｖｅｌｏｐｍｅｎｔｆｏｒｃｅｆｕｌｌｙ.Ｂｕｔｉ… 相似文献
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ＴｅｘｔａｎｄＶｏｉｃｅＩｎｔｅｇｒａｔｅｄＰａｇｉｎｇＳｙｓｔｅｍＳｈｅｎＬｉａｎｆｅｎｇ（沈连丰）ＷｅｉＨｕｉｈａｉ（魏慧海）ＷａｎＳｈａｎ（万山）（ＮａｔｉｏｎａｌＣｏｍｍｕｎｉｃａｔｉｏｎｓＲｅｓｅａｒｃｈＬａｂｏｒａｔｏｒｙ，Ｄｅｐａｒｔｍ... 相似文献
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YE Jia jun CHEN Jian QIAN Ying TIAN Yang lin 《上海大学学报(英文版)》1999,3(3):214-217
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ ＴｈｅＯＦＤＭｔｅｃｈｎｏｌｏｇｙｉｓｗｉｄｅｌｙｕｓｅｄｉｎｔｈｅｍｏｄｅｒｎｈｉｇｈｓｐｅｅｄｄａｔａｃｏｍｍｕｎｉｃａｔｉｏｎａｐｐｌｉｃａｔｉｏｎｓ,ｓｕｃｈａｓｔｈｅｄｉｇｉｔａｌｂｒｏａｄｃａｓｔｉｎｇｓｙｓｔｅｍｉｎｃｌｕｄｉｎｇＤＶＢ（ｔｈｅｄｉｇｉｔａｌｖｉｄｅｏｂｒｏａｄｃａｓｔｉｎｇ）ａｎｄＤＡＢ（ｔｈｅｄｉｇｉｔａｌａｕｄｉｏｂｒｏａｄｃａｓｔｉｎｇ）,ｔｈｅｂｒｏａｄｂａｎｄａｃｃｅｓｓｎｅｔｗｏｒｋｉｎｃｌｕｄｉｎｇＡＤＳＬ（ｔｈｅａｓ… 相似文献
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Ju Jianhua Mo Yaowu Huang Xiaoqin Xia Yiben 《上海大学学报(英文版)》1998,2(4):337-341
ｏｎ ａｎｄ Ｈｏｍｏｇｅｎｉｚａｔｉｏｎ ｏｆ Ｄｉａｍｏｎｄ Ｆｉｌｍ ｉｎ ｔｈｅ Ｍｕｌｔｉｆｉｌａｍｅｎｔ ＣＶＤ ＳｙｓｔｅｍTX１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｈｏｔ－ｆｉｌａｍｅｎｔｃｈｅｍｉｃａｌｖａｐｏｒｄｅｐｏｓｉｔｉｏｎ（ＨＦＣ... 相似文献
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The effects of parasitic capacitance in induction motor system are unnoticed when it is fed from the AC line,but they are obvious when supplied directly from a PWM inverter,Consequently,many parasitic problems occur.Such as motor-to-earth leakage current.Bearing current.incoming line current distortion and uneven distribution of electrical stresses along the winding.On the basis of the uniform transmission line principle.a complete equivalent circuit of the PWM inverter-fed motor system is presented,based on which all the capacitive parasitic problems mentioned obove are analyzed and simulated by means of PSPICE.All the results are consistent with the existing ones. 相似文献
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To elucidate the principles of notable torque and flux ripple during the steady state of the conventional direct torque control (DTC) of induction machines, the factors of influence torque variation are examined. A new torque ripple minimization algorithm is proposed. The novel method eradicated the torque ripple by imposing the required stator voltage vector in each control cycle. The M and T axial components of the stator voltage are accomplished by measuring the stator flux error and the expected incremental value of the torque at every sampling time. The maximum angle rotation allowed is obtained. Experimental results showed that the proposed method combined with the space vector pulse width modulation(SVPWM) could be implemented in most existing digital drive controllers, offering high performance in both steady and transient states of the induction drives at full speed range. The result of the present work imphes that torque fluctuation could be eliminated by imposing proper stator voltage, and the proposed scheme could not only maintain constant switching frequency for the inverter, but also solve the heating problem and current harmonics in traditional induction motor drives. 相似文献
14.
ALA转子电机具有与普通电机不同的结构,但与普通电机一样,直接转矩控制也能改善其动态性能和抗干扰能力,同时也存在较大的电流、磁链和转矩脉动,逆变器开关频率不恒定,高频噪声等问题、为此,在速度PI调节器中采用了具有快速响应,对参数变化及扰动不灵敏的滑模变结构控制,仿真结果表明有很好的效果。 相似文献
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A novel topology of the current-source grid-connected inverter is proposed based on the immittance converter theory. A control strategy of sine-sine pulse width modulation （PWM） is studied. Compared with the traditional current-source inverter, the power frequency inductors and power frequency transformer are replaced with high frequency inductors and a high frequency transformer. Thus, the proposed inverter has advantages of small volume, low cost, low total harmonic distortion （THD）, low power losses, high power factor （PF） and simple control. Furthermore, grid voltage cannot influence output current of the grid-connected inverter and the current-source inverter with a high PF that approaches one has been realized. Finally, validity of the theory analysis and feasibility of the control scheme are shown by simulation and experimental results. 相似文献
16.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｉｔｉｓｗｅｌｌｋｎｏｗｎｔｈａｔｔｈｅｔｏｒｑｕｅｄｅｖｅｌｏｐｅｄｂｙａｐｅｒｍａｎｅｎｔｍａｇｎｅｔｂｒｕｓｈｌｅｓｓｄｃｍｏｔｏｒｉｓｐｒｏｐｏｒｔｉｏｎａｌｔｏｔｈｅｍａｇｎｉｔｕｄｅｏｆｍｏｔｏｒｐｈａｓｅｃｕｒｒｅｎｔｓ.ＴｈｉｓｌｉｎｅａｒｒｅｌａｔｉｏｎｓｈｉｐｍａｋｅｓｉｔｃｏｎｖｅｎｉｅｎｔｔｏｃｏｎｔｒｏｌＢＬＤＣＭｔｏｒｑｕｅｐｒｏｄｕｃｔｉｏｎｂｙｒｅｇｕｌａｔｉｎｇｔｈｅｍｏｔｏｒｐｈａｓｅｃｕｒｒｅｎｔｓ[1].Ｉｎｔｈｉｓｐａｐｅｒ,ｔｈ… 相似文献
17.
PWM逆变器载波方式的选择 总被引：1，自引：2，他引：1
In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described in detail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the output frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switching PWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization of the DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current waveform. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonancetrigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear. 相似文献
18.
张小青 《咸阳师范专科学校学报》2013,(6):21-24
电流滞环跟踪PWM控制技术能较好地得到三相对称正弦波电流,以电流滞环跟踪PWM控制器为内环,转速外环调节器选用PI调节器,建立异步电动机双闭环调速系统.建立系统主电路及控制电路进行仿真模型,主电路由异步电动机模块、电动机测量单元模块、逆变器模块、直流电源、负载模块等组成,控制电路由转速给定信号、转速调节器、电流给定信号及电流滞环跟踪控制器等组成.仿真得到电流、转速及电磁转矩曲线,验证了方法的有效性. 相似文献
19.
倪伟 《温州职业技术学院学报》2011,11(4):66-69
异步电动机在船舶辅机中得到广泛应用,但异步电动机直接起动过程中存在起动电流大、起动转矩低的缺陷。针对异步电动机直接起动存在的缺陷,设计基于DSP的变频起动装置和编写调试软件,进行异步电动机变频起动。结果表明,基于DSP的异步电动机变频起动技术具有重要的应用价值。 相似文献