JP2010032311A - Method for detecting open-phase - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for detecting open-phase without using an electric circuit for detecting the open-phase, when the open-phase occurs in a three-phase alternating current power supply, concerning a device into which the three-phase alternating current power supply is inputted. <P>SOLUTION: In the device into which the three-phase alternating current power supply is inputted, a three-phase voltage detected value detected by a detector built in the device, for detecting a three-phase voltage of the three-phase alternating current power supply is subjected to three phase-two phase conversion performed by an operation processor built in the device, and separated into an effective voltage component and a reactive voltage component, and the open-phase is detected by determining whether the three-phase alternating current power supply has the phase interruption or not from fluctuation of the reactive voltage component. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a device for inputting a three-phase AC power supply, and relates to a method for detecting an open phase of the input three-phase AC power supply.

  In a device for inputting a three-phase AC power supply (hereinafter simply referred to as “device”), when any one of the three-phase AC power supplies is in a phase-open state (hereinafter simply referred to as “phase-losed”), the device is continuously operated. This is dangerous, and it is necessary to detect the phase loss and stop the device. In the device, which is dangerous when the operation is continued with the phase loss, a phase loss detection circuit for detecting the phase loss is usually installed, and the phase loss detection circuit has an electric circuit for detecting the phase loss. A circuit is configured. The device is configured to stop when the phase loss detection circuit detects the phase loss.

  FIG. 3 shows an example of a conventional device 9 for inputting a three-phase AC power source to which a phase loss detection circuit is attached, and will be described below with reference to FIG.

  The three-phase AC power source 1 is connected to the device 9. A phase loss detection circuit 10 is built in the device 9. An electric circuit for detecting an open phase of the three-phase AC power supply 1 is configured in the open phase detection circuit 10. When any one of the three-phase AC power supplies 1 has a phase loss, the phase loss detection circuit 10 detects the phase loss and outputs a device stop signal 6 for stopping the device 9. 9 is stopped.

As described above, the phase loss detection circuit that detects the phase loss of the three-phase AC power supply attached to the apparatus can detect the phase loss, but the phase loss detection circuit detects the phase loss. Therefore, an electric circuit configuration is required. In order to configure an electrical circuit for detecting the phase loss, a large number of electrical components are required, and the circuit configuration is complicated. For example, Japanese Patent Application Laid-Open No. 2007-17187 and Japanese Patent Application Laid-Open No. 2005-261157 have proposed many electric circuit configurations of the phase loss detection circuit. (For example, see Patent Documents 1 and 2)
JP 2007-17187 JP 2005-261157 A

  In view of the above, the present invention provides a method for detecting a phase loss of a three-phase AC power supply without using an electric circuit for phase loss detection.

  The present invention relates to a device for inputting a three-phase AC power source, and a three-phase voltage detection value detected by a detector for detecting a three-phase voltage of the three-phase AC power source incorporated in the device. A three-phase to two-phase conversion is performed by a built-in arithmetic processing unit to separate into an effective voltage component and an ineffective voltage component, and it is determined whether the three-phase AC power supply is in a phase loss from a change in the ineffective voltage component. .

According to the present invention, it is possible to detect an open phase of a three-phase AC power supply without using an electric circuit for detecting an open phase.

FIG. 1 shows an embodiment of the present invention, which will be described below with reference to FIG.
The three-phase AC power source 1 is connected to a device 2 for inputting the three-phase AC power source according to the present invention, and a three-phase voltage detector 3 and an arithmetic processor 5 are built in the device 2.

  The voltage of the three-phase AC power source 1 is detected by the three-phase voltage detector 3, and the detected three-phase voltage detection signal 4 is input to the arithmetic processor 5. The arithmetic processor 5 performs three-phase to two-phase conversion on the input three-phase voltage detection signal 4 in synchronization with the frequency of the three-phase AC power source 1 as shown in FIG. The reactive voltage component 8 is obtained.

  When the three-phase AC power supply 1 is normal, the value of the reactive voltage component 8 does not change greatly every sampling and becomes a substantially constant value every time.

  When any one of the three-phase AC power supplies 1 is open, the three-phase voltage detection signal 4 that is an output from the three-phase voltage detector 3 is a detection signal for the phase that is the open phase. The value of the reactive voltage component 8 obtained by the three-phase to two-phase conversion by the arithmetic processor 5 varies greatly from the normal time. The arithmetic processor 5 determines that the three-phase AC power supply 1 is in the open phase based on the fluctuation of the value of the reactive voltage component 8, and the arithmetic processor 5 outputs a device stop signal 6 for stopping the device 2. Then, the device 2 is stopped.

  As a result, it is possible to detect the phase loss of the three-phase AC power supply without using an electric circuit for phase loss detection, simplifying the device that inputs the three-phase AC power supply, downsizing, and simplifying maintenance Can be realized.

Explanatory drawing which showed the implementation method of Claim 1. (Example) Explanatory drawing of a three-phase-two phase conversion. Explanatory drawing of the apparatus which inputs the conventional three-phase alternating current power supply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Three-phase alternating current power supply 2 The apparatus which inputs the three-phase alternating current power supply by this invention 3 Three-phase voltage detector 4 Three-phase voltage detection signal 5 Arithmetic processor 6 Device stop signal 7 Effective voltage component 8 Invalid voltage component 9 Conventional three-phase AC power input device 10 Phase loss detection circuit

Claims (1)

In a device for inputting a three-phase AC power source, a three-phase voltage detection value detected by a detector for detecting a three-phase voltage of the three-phase AC power source incorporated in the device is used as an arithmetic processing incorporated in the device. Phase loss detection is performed by separating the effective voltage component and the reactive voltage component by a three-phase to two-phase conversion using a detector, and determining whether the three-phase AC power supply is in an open phase state based on fluctuations in the reactive voltage component. Method.

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