专利快速检索-快速检索全球专利，免费商用专利数据库-IPRDB

21. 发明专利

JPS55109131A COTNROLLER FOR DC TRANSMISSION APPARATUS 失效
公开(公告)号：JPS55109131A
公开(公告)日：1980-08-22
申请号：JP1427079
申请日：1979-02-13
申请人： HITACHI LTD
发明人： KONISHI HIROO , KAWAI TADAO
IPC分类号： H02H3/00 , H02J1/00

22. 发明专利

JPS53131447A CONTROL OF POWER INVERTOR IN USE FOR POWER TRFNSMISSION 失效
公开(公告)号：JPS53131447A
公开(公告)日：1978-11-16
申请号：JP4572077
申请日：1977-04-22
申请人： HITACHI LTD
发明人： KAWAI TADAO
IPC分类号： H02J1/00 , H02J3/36
摘要： PURPOSE:To omit the controlling signal transmission circuit by controlling at constant voltage a power invertor by inputting a value to which a fixed bias determined by DC current and DC line resistance is applied into the DC current of the power invertor side in a AC-DC linked system.

23. 发明专利

JPS5295029A GATE PULSE CONTROL SYSTEM FOR AC*DC CONVERTER 失效
公开(公告)号：JPS5295029A
公开(公告)日：1977-08-10
申请号：JP1139176
申请日：1976-02-06
申请人： HITACHI LTD
发明人： KINDOU HISAAKI , KAWAI TADAO , FUJII NORITOSHI
IPC分类号： H02M7/155 , G05F1/10 , H02M7/515 , H02M7/757
摘要： PURPOSE:To prevent commutation failure during switching by sending gate shift command while considering timing of gate pulse.

24. 发明专利

JPS5145247A 失效
公开(公告)号：JPS5145247A
公开(公告)日：1976-04-17
申请号：JP11815774
申请日：1974-10-16
申请人： HITACHI LTD
发明人： KUBO TAKAO , KAWAI TADAO
IPC分类号： H02H3/26 , H02H3/30

25. 发明专利

JPH03277121A CONTROL AND PROTECTION SYSTEM FOR SELF-EXCITATION TYPE CONVERTER 失效
公开(公告)号：JPH03277121A
公开(公告)日：1991-12-09
申请号：JP7333190
申请日：1990-03-26
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： SHIMAMURA HIDEHIKO , KAWAI TADAO , TOKIWA YUKIO , SUZUKI KENICHI
IPC分类号： H02H7/122 , H02H7/16 , H02J3/18
摘要： PURPOSE:To protect a self-excitation type converter safely and surely and to control an effective use of equipment by detecting a discharge current of a direct-current capacitor when a trouble occurs, controlling discharge of the direct-current capacitor rapidly and by using the control function effectively even during the trouble. CONSTITUTION:A control and protection device 600 controls a converter and a direct-current switch 51 according to each relay operation signal. When a direct current short circuit occurs on the direct current side, a discharge current of a capacitor 40 flows toward the point where the short circuit occurred from the capacitor 40 while a high-speed direct over-current relay 100 installed on a direct-current capacitor circuit starts operation when it exceeds a detection sensitivity, opening a direct-current switch 51 to cut off the faulty current. From the start of the direct-current switch to the settlement of the trouble, the reactive power of an alternating current can be under control by the energy of the direct-current capacitor 40.

26. 发明专利

JPH03264867A METHOD AND DEVICE FOR PROCESSING DIGITAL SIGNAL 失效
公开(公告)号：JPH03264867A
公开(公告)日：1991-11-26
申请号：JP6493990
申请日：1990-03-15
申请人： HITACHI LTD
发明人： KIDO MITSUYASU , CHIBA TOMIO , KUDO HIROYUKI , KAWAKAMI JUNZO , KAWAI TADAO
IPC分类号： G01R31/08 , G01R19/02 , G01R19/25
摘要： PURPOSE:To enable removal of a harmonic content of the frequency of an alternating- current signal at all times even when the frequency fluctuates, by detecting the frequency of the alternating-current signal from an output signal of a digital filter and by adjusting the gain characteristic of the digital filter so that it is matched with the detected frequency. CONSTITUTION:A signal obtained by sampling an alternating-current signal and subjecting the sampled signal to A/D conversion is inputted to an adaptive digital filter 1a, and a signal of a specified frequency component is extracted therefrom and outputted to a peak value detecting processing element 1b and a frequency detecting processing element 1d. A peak value of the signal is calculated by a prescribed formula in the processing element 1b, and based on the peak value, an effective value is calculated by a prescribed formula in an effective value calculating arithmetic element 1c. Based on the frequency of the alternating-current signal detected in the processing element 1d, such a filter coefficient as to make the detected frequency by the central frequency of the filter 1a is calculated in a filter coefficient calculating processing element 1e. According to this coefficient, the gain characteristic of the filter 1a is adjusted. Thereby the gain of the alternating-current signal inputted to the filter 1a can be made invariable at all times even when the frequency of the alternating-current signal fluctuates.

27. 发明专利

JPH0221222B2 失效
公开(公告)号：JPH0221222B2
公开(公告)日：1990-05-14
申请号：JP17083782
申请日：1982-10-01
申请人： HITACHI LTD
发明人： TAMAI MAKOTO , KAWAI TADAO
IPC分类号： H02M5/48 , G05F1/00 , G05F1/10 , H02M5/45

28. 发明专利

JPH01170318A RATIO DIFFERENTIAL RELAY 失效
公开(公告)号：JPH01170318A
公开(公告)日：1989-07-05
申请号：JP32577687
申请日：1987-12-23
申请人： HITACHI LTD , TOKYO ELECTRIC POWER CO
发明人： MATSUI YOSHIAKI , SANO KAZUHIRO , KAWAI TADAO , SASAKI HIROSHI , OURA YOSHIFUMI , YOSHIDA KAZUYOSHI , MAEDA TAKAFUMI
IPC分类号： H02H3/28
摘要： PURPOSE:To effectively distinguish a detection current due to an internal accident from that due to an external accident by obtaining an operation amount and a suppression amount at the time of nonsaturation in each cycle of a line current, and detecting the amplitude of a differential value due to a phase difference with an accident current. CONSTITUTION:A ratio differential relay is composed of operation amount calculating means, suppression amount calculating means and accident discriminating means. The operation amount calculating means calculates the sum of the momentary values of two line currents, calculates the operation amount of the relay on the basis of the absolute values of the difference of the present value of the sum of the calculated momentary values and a value before a predetermined time, calculates the scalar sum of the momentary values of the two line currents, and calculates the suppression amount of the relay on the basis of the absolute value of the difference of the present value of the calculated scalar sum and a value before a predetermined time. The accident discriminating means calculates the difference value between the operation amount and the suppression amount, and discriminates the content of the accident on the basis of the difference value.

29. 发明专利

JPS63240313A DIGITAL PROCESSOR 失效
公开(公告)号：JPS63240313A
公开(公告)日：1988-10-06
申请号：JP7031887
申请日：1987-03-26
申请人： HITACHI LTD
发明人： CHIBA TOMIO , KUDO HIROYUKI , KIDO MITSUYASU , MATSUI YOSHIAKI , KAWAI TADAO
IPC分类号： H02H3/00 , G06F13/20 , G06F17/10

30. 发明专利

JPS63177218A INPUT CIRCUIT FOR DIGITAL OPERATION AND SIGNAL PROCESSING EQUIPMENT 失效
公开(公告)号：JPS63177218A
公开(公告)日：1988-07-21
申请号：JP805287
申请日：1987-01-19
申请人： HITACHI LTD
发明人： KIDO MITSUYASU , CHIBA TOMIO , KUDO HIROYUKI , KAWAI TADAO
IPC分类号： G06F3/05 , G01R19/00 , H02H3/02 , H03M1/12
摘要： PURPOSE:To obtain a compact digital operation/signal processing equipment by using a multiplex filter that uses an operational amplifier in time division to form said processing device just with a single filter and a single sample and holding circuit. CONSTITUTION:The input signals of voltages Va, Vb and Vc and currents Ta, Ib and Ic of an electric power system are applied to input terminals i1...i7 of a multiplex filter 1. Thus the filter 1 obtains the output in time division against a multi-input signal. This output is sampled and held by a sample and holding S/H circuit 2 and changed into digital signals by an A/D converter 3. The signals of said voltages and currents are stored in a RAM 8 via a buffer 4 and processed there. In such constitution, a digital operation and signal processing are carried out just with use of a single filter and a single sample and holding circuit despite the presence of plural input signals.

你已经成功收藏专利！

检索式保存成功!

IPRDB

热门服务

关于我们

友情链接

联系方式