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Overvoltage protection device and current adjustment circuit

A protection device and current adjustment technology, which is applied to emergency protection circuit devices, emergency protection circuit devices, and circuit devices for limiting overcurrent/overvoltage, and can solve the problems of thyristor temperature rise, late restart, and long waiting time Counting seconds and other issues to achieve the effect of simple composition

Active Publication Date: 2018-03-13
KK TOSHIBA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0016] However, in the conventional method, when the current flowing through the first crowbar 12 becomes zero due to the application of the reverse voltage, the short-circuit current flowing through the first crowbar 12 flows into the inverter 7 at time t4, The voltage of the DC support capacitor 8 increases again, and the situation that the chopper 11 and the first short circuiter 12 operate again exists.
As a result, the temperature of the resistor 9 constituting the chopper 11, the power semiconductor element 10, and the thyristor constituting the first crowbar 12 rises, possibly leading to destruction.
[0017] Here, when the ratings of the chopper 11 and the first crowbar 12 are increased to withstand reoperation, the cost and occupied area increase.
[0018] In addition, the current flowing in the first crowbar 12 decays according to the time constant of the secondary winding of the wound type induction motor 1, so it waits until the current becomes zero, as the reactance of the wound type induction motor 1 becomes larger , the waiting time is on the order of several seconds, and the restart becomes late

Method used

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  • Overvoltage protection device and current adjustment circuit
  • Overvoltage protection device and current adjustment circuit
  • Overvoltage protection device and current adjustment circuit

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no. 1 approach

[0029] refer to figure 1 as well as figure 2 The first embodiment will be described.

[0030] figure 1 It is a diagram showing an example of a circuit configuration including a secondary overvoltage protection device of the wound-type induction motor 1 according to the first embodiment. Also, for Figure 4 Common elements are denoted by the same reference numerals.

[0031] Such as figure 1 As shown, the primary winding terminal of the wound induction motor 1 is connected to the power system 3 via the main transformer 2 and the transmission line 4 . The voltage of the primary winding terminal of the wound-type induction motor 1 is converted into a voltage equivalent to that of the power system 3 by the main transformer 2 , and then supplied to the power system 3 via the transmission line 4 .

[0032] The inverter 7 is connected to the secondary winding terminal of the wound-type induction motor 1 via the first short circuit 12 . The frequency converter 7 includes an ...

no. 2 approach

[0049] refer to figure 1 , figure 2 and image 3 A second embodiment will be described. In addition, the same code|symbol is attached|subjected to the element common to 1st Embodiment. Hereinafter, the description of the parts common to the first embodiment will be omitted, and the different parts will be mainly described.

[0050] In the second embodiment, a mechanical circuit breaker is used instead of image 3 The shown semiconductor circuit breaker constitutes the aforementioned second short circuit breaker 14 . Specifically, a semiconductor circuit breaker is constituted by a power semiconductor element such as an IGBT or a GTO, and a diode connected in antiparallel thereto. By connecting them in anti-series, an alternating current can always flow.

[0051] With such a configuration, the current capacity and the number of parallel connections of the semiconductor circuit breaker are determined by the current flowing to the semiconductor during normal operation. A...

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Abstract

The present invention provides an overvoltage protection device capable of recovering from a system failure in a short time with a simple configuration. An overvoltage protection device according to an embodiment is provided between a secondary side of a wound-type induction motor and an inverter that excites the secondary side of the wound-type induction motor with a three-phase The first short circuit with the function of phase-to-phase short circuit, the overvoltage protection device has: a resistor connected between the first short circuit and the frequency converter for each phase; and a second short circuit connected to the resistor The inverter is connected in parallel and has the function of short-circuiting the inverter and the secondary side of the wound induction motor.

Description

technical field [0001] Embodiments of the present invention relate to an overvoltage protection device for protecting a secondary winding of a wound-type induction motor and an inverter from overvoltage, and a current adjustment circuit included in the overvoltage protection device. Background technique [0002] In configurations such as the static scherbius method and the super-synchronous scherbius method in which the primary side of the wound induction motor is connected to the power system and the secondary side is excited with slip frequency alternating current, the When the primary side of a wound-type induction motor becomes unbalanced, a reverse-phase current flows, and 2f flows in the secondary side 1 ±sf 1 (where, f 1 is the frequency of the system, and s represents the slip. ) frequency current. In addition, when the direct current amount is multiplied by the primary side, a current of fr (rotational frequency of the rotor) flows through the secondary side. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/09H02H9/02H02P23/00H02P23/07H02P29/032
CPCH02H7/06H02H7/12H02H9/002H02P9/007H02P29/0241H02P6/005H02P29/024
Inventor 长谷川隆太石月照之藤田崇影山隆久北森勇太朗佐藤翔
Owner KK TOSHIBA
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