JP2011120366A - Overvoltage protection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overvoltage protection device that interrupts application of voltage to electrical apparatuses, maintains the state, and thereby preventing the electrical apparatuses from being damaged due to the application of overvoltage, when an overvoltage applied to the electrical apparatuses is detected. <P>SOLUTION: The overvoltage protection device applies voltage to a direct current conversion means 3 via a power distribution retaining means 2 composed of a non-retaining SW2a that switch on and off alternating current power supply and a power distribution retaining relay 2b. When a voltage detection means 5 determines that a voltage detected exceeds a predetermined one, a control means 4 switches off the power distribution relay, and thereby preventing the electric equipment from being damaged by the application of overvoltage with a simple structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an overvoltage protection device that blocks and protects the application of voltage to a device without destroying the device when an overvoltage is applied to the electronic device.

  Conventionally, an electronic device connected to a commercial power source may be destroyed by application of an overvoltage, and measures to prevent this are taken. For example, in the case of a commercial power supply that uses a single-phase power supply for each phase voltage (AC220V in China) of a three-phase four-wire AC power supply in China or the like, the voltage of the single-phase power supply is the worst AC380V due to the missing phase of the neutral line Therefore, there is a possibility that an electronic device connected to a commercial power source may be destroyed by applying an overvoltage. For this reason, there is an apparatus provided with an overvoltage protection device that prevents destruction of electronic equipment due to overvoltage application. Some measures are taken.

  Conventionally, as a conventional overvoltage protection device, a configuration in which a normally closed contact relay is provided on the primary side of a power transformer of a power circuit that uses a power transformer, a rectifier circuit, and a smoothing capacitor as an AC power source, A voltage detection means for detecting the output voltage and a drive means for opening the contact of the relay by the output by the overvoltage detection of the voltage detection means are provided. When an overvoltage is detected, the power transformer is cut off and the overvoltage to the power supply circuit is detected. Some of them prevented application. (For example, refer to Patent Document 1).

  FIG. 2 is a configuration diagram of a conventional overvoltage protection device described in Patent Document 1. In FIG. The AC power source 1 is turned into a DC power source by the power transformer 101, the rectifier circuit 102, and the smoothing capacitor 103, and is supplied to the operation circuit control unit 104. On the primary side of the power transformer 101, a normally closed contact relay 105 is connected in series with one end thereof. The rectifier circuit 102 is connected to the secondary side of the power transformer 101, and the smoothing capacitor 103 is connected to the output side. On the output side of the smoothing capacitor 103, voltage detecting means 106 for detecting the smoothed voltage and driving means 107 for opening the relay 105 are provided. A power supply interrupting means 108 for interrupting power supply to the operation circuit control section 104 when the voltage detection means 106 detects an overvoltage is connected to the operation circuit control section 104 in series.

  When the voltage of the AC power supply 1 is the rated voltage, since the contact of the relay 105 is closed, the rated voltage is applied to the primary side of the power transformer 101. Since the voltage detected by the rectifier circuit 102 and the smoothing capacitor 103 is within the normal range by the voltage detection means 106, the drive means 107 does not operate and the power supply interruption means 108 does not operate.

  When the voltage of the AC power supply 1 becomes higher than the rated voltage and exceeds a predetermined voltage, the contact of the relay 105 is initially closed, so that the voltage of the AC power supply 1 is applied to the primary side of the power transformer 101. Since the voltage converted into the DC power supply by the rectifier circuit 102 and the smoothing capacitor 103 is a high voltage exceeding the normal range by the voltage detection means 106, when the voltage detection means 106 detects this high voltage, the drive means 107 At the same time, the power supply cutoff means 108 is also operated, and the power supply to the operation circuit control unit 104 is cut off. As a result, the contact of the relay 105 is opened, and power supply to the power transformer 101 is interrupted.

JP-A-9-93941

  However, in the conventional configuration, the operation of the driving unit 107 is maintained while the smoothing capacitor 103 is charged even after the power supply to the primary side of the power transformer 101 is cut off due to the contact of the relay 105 being opened. Is done. However, when the smoothing capacitor 103 is discharged and drops to a voltage in the normal range, the driving means 107 stops, the contact of the relay 105 returns to the closed state, and returns to the initial state. When the relay 105 is closed, the voltage of the AC power supply 1 is applied to the primary side of the power transformer 101 again, and the above operation is repeated.

  The AC power supply 1 can be shut off and the electronic device can be protected if immediately noticed the abnormality of the opening / closing operation of the relay 1051, but if the abnormality is not noticed, the opening / closing operation of the relay 105 is repeated during the period when the overvoltage is applied. Therefore, the contact life of the relay is not preferable.

  Further, since the voltage detected by the voltage detection means 106 is on the secondary side of the power transformer 101, it varies depending on the power consumption of the operation circuit control unit 104. Therefore, in the case of an electronic device in which the power consumption of the operation circuit control unit 104 is not constant, there is a problem that it cannot be accurately protected.

  The present invention solves the above-described conventional problems, and overvoltage protection that accurately detects an overvoltage applied to an electronic device and interrupts the voltage application to the device when the application of the overvoltage is detected and maintains the state. An object is to provide an apparatus.

  In order to solve the above-mentioned conventional problems, the overvoltage protection device of the present invention includes a non-holding type SW for turning ON / OFF an AC power source and a current holding means comprising a current holding relay, a diode bridge for rectifying and smoothing the AC power source, DC control means comprising a capacitor, control means for driving the energization holding relay, and voltage detection means for detecting the level of the DC voltage converted by the DC conversion means, the control means being the non-holding type SW The operation is started when the power is turned on and the excitation signal to the energization holding relay is output to turn on the energization holding relay. When the voltage detected by the voltage detecting means is higher than the predetermined value, the excitation signal is turned off and the energization holding relay is turned on. It is set to OFF.

  As a result, it is possible to provide an overvoltage protection device that accurately detects an overvoltage applied to an electronic device and interrupts the voltage application to the device and maintains the state when the application of the overvoltage is detected.

  The overvoltage protection device of the present invention accurately detects an overvoltage applied to an electronic device, and when an overvoltage application is detected, the overvoltage protection device cuts off the voltage application to the device and maintains the state, thereby preventing the electronic device from overvoltage application. Can be prevented.

Configuration diagram of overvoltage protection device according to Embodiment 1 of the present invention Configuration of conventional overvoltage protection device

The present invention drives an energization holding relay comprising a non-holding type SW for turning ON / OFF an AC power supply and an energization holding relay, a diode bridge for rectifying and smoothing the AC power supply, a DC conversion means comprising a smoothing capacitor, and the energization holding relay. And a voltage detection means for detecting the level of the DC voltage converted by the DC conversion means. The control means starts operation when the non-holding SW is turned on and excites the energization holding relay. A signal is output and the energization holding relay is turned on. When the voltage detected by the voltage detecting means is higher than a predetermined value, the excitation signal is turned off and the energization holding relay is turned off, thereby overvoltage applied to the electronic device. When it is detected accurately and the application of overvoltage is detected, the voltage application to the device can be cut off and the state can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram of an overvoltage protection device according to a first embodiment of the present invention.

  The AC power source 1 is connected to a DC conversion means 3 including a diode bridge 3a and a smoothing capacitor 3b via an energization holding means 2 including a non-holding type SW 2a and an energization holding relay 2b, and is converted into a DC voltage. This DC voltage is supplied to a load 7 via the control unit 4 and the control unit 4 as control means by a power supply circuit 6 such as a switching power supply for converting into a low voltage. The controller 4 is configured to output an excitation signal to the energization holding relay 2b when the operation is started by power supply from the power supply circuit 6. On the output side of the DC conversion means 3, voltage detection means 5 for detecting the level of the DC voltage is provided. The output of the voltage detection means 5 is input to the control section 4, and the control section 4 determines whether or not the voltage detected by the voltage detection means 5 is higher than a predetermined voltage. It is configured to turn off the excitation signal to.

When the voltage of the AC power supply 1 is the rated voltage, the AC power is applied to the DC conversion means 3 by turning on the non-holding type SW 2 a, and the power is supplied to the control unit 4 via the power supply circuit 6. When the control unit 4 starts operation, an excitation signal is output to the energization holding relay 2b, and the energization holding relay 2b is turned on. At this time, even if the non-holding type SW 2a is OFF, the energization to the control unit 4 is held by the energization holding relay 2b, and the control unit 4 continues to operate. Since the voltage converted into the DC voltage by the DC converter 3 is detected to be in the normal range by the voltage detector 5, the excitation signal output from the control unit 4 to the energization holding relay 2b is continued and the normal operation is continued. To do. Without
Next, when the voltage of the AC power source 1 becomes higher than the rated voltage and exceeds a predetermined voltage, the voltage converted into the DC voltage by the DC conversion unit 3 is detected by the voltage detection unit 5 and input to the control unit 4. The The control unit 4 detects that the voltage exceeds the normal range, and the excitation signal from the control unit 4 to the energization holding relay 2b is turned off, and the energization holding relay 2b is turned off. As a result, the voltage input to the DC conversion means 3 is cut off, the power supply to the control unit 4 is also cut off, and the control unit 4 stops its operation. Even if the operation of the control unit 4 stops, the excitation signal to the energization holding relay 2b remains OFF and does not change, so the operation of the energization holding relay 2b does not change and the voltage input interruption to the DC conversion means 3 is continued. .

  Thereby, when an overvoltage is applied, the overvoltage protection apparatus which interrupts | blocks the voltage supply to an electronic device and continues the state can be implement | achieved.

  Since the circuit does not include a power transformer, the voltage detected by the voltage detection means 6 does not depend on the power consumption of the control unit 4 and the load 12, and accurate detection is possible.

  The circuit in this embodiment can be applied to various electric devices. For example, when used for the operation of an indoor unit of an air conditioner, a fan motor or the like can be driven as a load.

As described above, when an overvoltage is applied, the overvoltage protection device according to the present invention can easily realize the function of cutting off the voltage supply to the electronic device and continuing the state with a small number of components. Therefore, it can be widely applied to many devices as a device for preventing destruction due to overvoltage of electronic devices.

1 AC power supply 2 Current holding means 2a1 Non-holding type SW
2b Current holding relay 3 DC conversion means 3a Diode bridge 3b Smoothing capacitor 4 Control unit 5 Voltage detection means 6 Power supply circuit 7 Load

Claims (1)

An energization holding means comprising a non-holding type SW for turning ON / OFF the AC power supply and an energization holding relay; a DC conversion means comprising a diode bridge for smoothing and smoothing the AC power supply; a smoothing capacitor; and a control means for driving the energization holding relay; Voltage detecting means for detecting the level of the DC voltage converted by the DC converting means, and the control means starts operation when the non-holding type SW is turned on and outputs an excitation signal to the energization holding relay. An overvoltage protection device, wherein an energization holding relay is turned on, and when the voltage detected by the voltage detection means is higher than a predetermined value, the excitation signal is turned off and the energization holding relay is turned off.

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