JP4425225B2 - Fuse blown and instantaneous power failure detection device and method - Google Patents

Description

  The present invention relates to a fuse blown and instantaneous power failure detection device and method for detecting blown fuses and instantaneous power failure (hereinafter referred to as instantaneous power failure) connected to a power supply path for a load.

  Conventionally, it is related to a fuse blown detection device, and a device used as a part of a power conversion device described in Patent Document 1 is known. FIG. 9 is a control block diagram showing a conventional fuse blown detection device.

  This power conversion device includes a rectifier unit 2 that rectifies alternating current and converts it into direct current and supplies it to a direct current main circuit, and an inverter unit 5 that converts direct current of the direct current main circuit into alternating current for supplying a motor 6 that is a load. A main circuit fuse 3 inserted in the main circuit line to protect each device from being damaged when the DC main circuit is short-circuited or grounded, a control microcomputer unit 7 for controlling the load, a DC main A voltage detection means 9 for detecting the voltage of the circuit and a means 7 for incorporating the voltage detected by the voltage detection means 9 into the control unit, and a signal indicating a change in the voltage detected by the voltage detection means 9, An abnormality of the DC main circuit including the melting of the circuit fuse 3 is detected. That is, it is used for control from the existing voltage detection means 9, for example, a DC voltage detection device configured to detect a DC voltage by converting the voltage into a signal having a pulse width corresponding to the voltage and converting the voltage to an analog signal. If the DC main circuit voltage detected for this purpose is input to the control microcomputer unit 7 as the main circuit fuse blow detection signal 10 for confirmation, and a DC voltage drop is detected even when the main circuit contactor is turned on, It is determined that the DC circuit abnormality includes melting of the circuit fuse 3, and the control microcomputer unit 7 is operated to stop the control.

  Moreover, what is described in patent document 2 is known as a thing regarding instantaneous power failure. FIG. 10 is a control block diagram illustrating a conventional instantaneous power failure detection device.

  In this arithmetic processing device (corresponding to a momentary power failure detection device), 11 is a commercial AC power supply, 12 is a step-down transformer, 13 is a rectifier comprising a diode bridge, 15 is a voltage dividing resistor for adjusting the voltage, 21 Is an A / D converter, and 22 is a magnitude comparator. The magnitude comparator 22 outputs an “H” signal when the input value from the A / D converter 21 is equal to or greater than a predetermined value (threshold value). Reference numeral 22a denotes a standby terminal of the magnitude comparator 22. When a power failure occurs, a signal is given to this terminal so that the magnitude comparator 22 is put into a standby state to operate to reduce power consumption.

  Reference numeral 30 denotes a microcomputer (CPU). Reference numeral 31 denotes an edge detection unit incorporated in the CPU 30 that detects rising and falling edges of the signal output waveform of the magnitude comparator 22 that is input. Reference numeral 32 denotes a timer, which starts timing after receiving the falling edge detection of the edge detection unit 31. Reference numeral 34 denotes a momentary power failure / power failure detection processing unit, which determines the momentary power failure / power failure detection from the edge detection of the edge detection unit 31 and the time limit of the timer 32 and executes corresponding processing. A clock 36 supplies a clock signal to each part in the microcomputer (CPU) 30, the A / D converter 21, and the magnitude comparator 22. The power failure detection unit is configured with the above circuit configuration.

  Reference numeral 37 denotes an arithmetic processing unit, which executes arithmetic processing of the main process, which is the main task of the arithmetic processing apparatus in FIG. That is, the instantaneous voltage of the AC power supply 11 is converted into a digital value by the A / D converter 21 and output when the digital value is greater than or equal to a predetermined threshold value by the magnitude comparator 22, and the edge detection unit 31 rises and falls in the output waveform. The timer 32 and the momentary power failure / power failure detection processing unit 34 detect a fall, and when the rise period (voltage drop period) exceeds the first time limit value T1, the main task When the voltage drop period exceeds the second time limit value T2 (T2> T1), it is determined that a power failure has occurred and a predetermined power failure process is performed. If power is restored during a momentary power failure or power failure, processing before the power failure is resumed.

JP 2003-333860 A JP 2003-5872 A

  However, in the conventional device, the device for detecting the blown fuse and the instantaneous power failure is constituted by independent circuits.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fuse blown and instantaneous blackout detection device and method capable of detecting fuse blown and instantaneous blackout with a single circuit.

In order to achieve the above object , the present invention provides a power supply apparatus in which a fuse and a switching element for turning on or off AC power are connected to a wiring path for supplying AC power from an AC power supply to a load. And a device for detecting an instantaneous power failure of AC power, when the AC voltage of the AC power supply is input and the presence or absence of the AC voltage is detected, and there is no AC voltage, there is no first voltage which is an identification signal indicating no voltage A voltage presence / absence detecting means for outputting a signal, a first timer for setting a first set time which is a limit time from a time at which the AC power supply starts to fail to a time at which it is regarded as a temporary instantaneous power failure, and a first setting Operation of the control power supply that supplies power to the fuse blown and instantaneous power failure detection device after a power failure can be maintained continuously from the time when the AC power source starts to fail. A second timer for setting the second set time is a limit time to time, enter the first voltage absence signal, the first voltage absence signal is a voltage there signals within the first set time First signal discrimination that outputs a second no-voltage signal that is an identification signal without voltage when it is determined whether or not the first voltage-less signal does not return to a signal with voltage. And a second no-voltage signal from the first signal discriminating means and whether the second no-voltage signal returns to a signal having a voltage at the second set time, When the no-voltage signal returns to the signal with voltage at the second set time, it is determined that the AC power supply has instantaneously failed, and an instantaneous power failure detection signal is output, and the second voltage-less signal has the second set time. If it does not return to a signal with voltage, it is determined that the AC power supply fuse has blown. A second signal discriminating means for outputting a Yuzu blown detection signal, characterized in that it comprises a. Thus, the fuse blown and instantaneous power failure detection device uses a single circuit including a voltage presence / absence detection means, a first timer, a second timer, a first signal discrimination means, and a second signal discrimination means. Fusing and instantaneous power failure can be detected. Therefore, there is no need to provide two circuits, a circuit for detecting a blown fuse and a circuit for detecting an instantaneous power failure.

  Preferably, the load is a heating power supply unit.

  The present invention also provides a device for detecting a fuse blown and an instantaneous power interruption of the AC power by connecting a fuse and a switching element for turning on or off the AC power to a wiring path for supplying AC power from an AC power source to a load. And a fuse blown and instantaneous power failure detection method in a power supply device that supplies power to the fuse blown and instantaneous power failure detection device, and detects the presence or absence of the AC voltage by inputting the AC voltage of the AC power supply. According to the result, when there is no AC voltage, the first step of outputting a first voltageless signal that is an identification signal of no voltage and the first voltageless signal as a temporary instantaneous power failure process, The second step of tentatively shutting off the first gate and the first no-voltage signal from the time when the AC power supply starts to fail to the time considered to be a temporary instantaneous power failure. A third step for determining whether or not to return to a signal with a voltage within a first set time, which is a limit time of the first time, and the result of the third step indicates that the first no-voltage signal has a voltage When returning to the signal, it is determined that the AC power supply is normal and the first voltage-less signal does not return to the signal with voltage due to the results of the fourth step and the third step of continuously operating the power supply device. A fuse after a power failure from the time when the second voltage-less signal exceeds the first set time by the second voltage-less signal, which is an identification signal without voltage outputted to the AC power source, and the AC power supply starts to fail. It is determined whether or not to return to a signal with voltage at a second set time, which is a limit time until the time when the operation of the control power supply for supplying power to the fusing and instantaneous power failure detection device can be continuously maintained. 5 steps and 5th As a result of the step, when the second signal without voltage returns to the signal with voltage, it is determined that the AC power supply has instantaneously failed, and the result of the sixth step and the fifth step of outputting the instantaneous power failure detection signal Thus, when the second no-voltage signal does not return to the voltage-present signal, it is determined that the fuse of the AC power source has blown, and a seventh step of outputting a fuse blow detection signal is provided.

  As described above, according to the present invention, since the fuse blow detection and the instantaneous power failure detection can be realized by a single circuit, space can be saved. Moreover, since the number of parts can be reduced, the reliability of the entire power supply device can be improved.

The best mode for carrying out the present invention will be described below with reference to the drawings.
〔Constitution〕
FIG. 1 is a schematic control block diagram when the fuse blown and instantaneous power failure detection device according to the present invention is applied to a heating power supply device. FIG. 2 is a supplementary explanatory diagram of FIG. Hereinafter, in order to simplify the description, the AC power source 52 is a single-phase AC power source. As shown in FIG. 1, the heating power source 51 includes an AC power source 52, a main circuit fuse (hereinafter referred to as a fuse) 53, a switching circuit 54, a load 55, a control power source 56, a switching cutoff signal generator 57, and A fuse blown / instantaneous power failure detection device 58-1 is provided.

  The AC power supply 52 is a single-phase AC power supply, for example, a power supply having a power supply frequency of 50 Hz or 60 Hz. Among the output terminals R and S of the AC power supply 52, the terminal R is connected to the primary side of the fuse 53. The fuse 53 is, for example, a semiconductor protection fuse (fast-acting type), and the secondary side of the fuse 53 is connected to the fuse blown / instantaneous power failure detection device 58-1 and the switching circuit 54. The switching circuit 54 includes two switching elements, for example, two thyristors (Silicon Controlled Rectifier). The secondary terminal of the fuse 53 is on the anode side of one thyristor, and the terminal S of the AC power supply 52 is on the cathode side of the other thyristor. Connected to. Other switching elements such as transistors and IGBTs (Insulated Gate Bipolar Transistors) can also be used. The load 55 is one or a plurality of heaters.

  The control power source 56 is a direct current power source for supplying required power to an electric circuit built in the instantaneous power failure / fuse blow detection device 58-1, which will be described later, and includes a storage capacitor. The control power supply 56 outputs a voltage corresponding to the electrostatic capacity of the storage capacitor for a predetermined time when the AC power supply 52 fails. With this voltage, the operation of the electric circuit inherent in the fuse blown and instantaneous power failure detection device 58-1 can be continued. In other words, when the AC power supply 52 fails, as shown in FIG. 8D, when a discharge time (corresponding to the second set time T2) corresponding to the capacitance of the storage capacitor has elapsed, the fuse is blown from the AC power supply 52. And the electric power supplied to the instantaneous power failure detection device 58-1 is completely cut off.

  The gate signal on / off selector 57 is a circuit that selects the gate signal C for turning on or off the gate of the switching element of the switching circuit 54 based on the presence or absence of the output voltage of the AC power supply 52. For example, FIG. As shown in FIG. 2, a latch circuit 64 and a logic circuit 65 are provided. The latch circuit 64 inputs a second no-voltage signal E, which will be described later, and outputs a latch signal G holding the second no-voltage signal E to the logic circuit 65. The reset signal is input to the latch circuit 64 and resets the latch signal G when the fuse blown and instantaneous power failure detection device 58-1 is restarted after the AC power source 52 is momentarily stopped, for example. The logic circuit 65 is, for example, an AND circuit, a first voltageless signal D described later, and a gate source signal F by a gate source signal generator (not shown) for turning on or off the gate of the switching element, For example, a square wave signal and a latch signal G are input, and a gate signal C for turning on or off the gate of the switching element based on the first no-voltage signal D and the latch signal G from the gate source signal F. Is output to the switching circuit 54.

  FIG. 3 is a control block diagram showing the fuse blown and instantaneous power failure detection device according to the present invention. FIG. 4 is a control block diagram showing voltage presence / absence detection means in the fuse blown and instantaneous power failure detection device according to the present invention.

  As shown in FIG. 3, the fuse blown and instantaneous power failure detection device 58-1 includes a voltage presence / absence detection means 59-1, a first timer 60, a first signal determination means 61, a second timer 62, and a second timer 62. A signal discrimination means 63 is provided.

  The voltage presence / absence detection means 59-1 is an electric circuit that detects whether or not there is an output voltage from the AC power supply 52. For example, as shown in FIG. 4, a square wave generator 66-1, a logic circuit 75, and a voltage are provided. A level detector 67 is provided. The square wave generator 66-1 is an electric circuit that generates a square wave signal from a sine wave signal from the AC power supply 52, and includes a current limiting resistor 68, a diode 69, a photocoupler 70, and a voltage detection resistor 71. . The current limiting resistor 68 is connected in series to the secondary side of the fuse 53. The diode 69 is connected in series with the fuse 53 and the current limiting resistor 68, and the cathode side is connected to the current limiting resistor 68.

The photocoupler 70 is an optical coupling element for electrically insulating an input signal and an output signal to the photocoupler 70, and transmits light between the input signal and the output signal, and noise along with the electrical insulation. It is difficult to convey. The photocoupler 70 is connected in parallel with the diode 69, the anode side of the diode in the photocoupler 70 is connected to the cathode side of the diode 67, and the collector side of the transistor in the photocoupler 70 is connected to the voltage detection resistor 71. The The emitter side of the transistor in the photocoupler 70 is grounded, and a DC voltage V _D , for example, 5 volts is applied between the voltage detecting resistor 71 and the ground. By detecting the terminal voltage of the voltage detecting resistor 71 connected to the transistor in the photocoupler 70, the square wave signal K on the plus side is obtained. The logic circuit 75 is, for example, a NOT circuit, which receives the square wave signal K which is the positive side high or low by the square wave generator 66-1, inverts the square wave signal K, and is low or high, respectively. A square wave signal is output to the voltage level detector 67.

  The voltage level detector 67 includes a filter circuit 72 and a comparator 73. The filter circuit 72 is an LC circuit, for example, and inputs the square wave signal and outputs an averaged signal, which is a signal obtained by averaging the levels of the square wave signal, to the comparator 73. The comparator 73 is a voltage comparator, and inputs the level of the averaged signal and a reference voltage value, for example, 1 volt, compares the level of the averaged signal with the reference voltage value, and calculates the average based on the calculation result. When the level of the activation signal is equal to or greater than the reference voltage value, High is output as an IPL (Instant Power Loss) signal for identifying the presence or absence of the output voltage of the AC power supply 52, and when it is small, Low is output. Here, the square wave signal from the square wave generator 66-1 is inverted by the NOT circuit because the output signal from the comparator 73 is converted into a Low signal when there is no output voltage from the AC power supply 52, thereby detecting the presence / absence of voltage. This is to make it easy to understand the correspondence between the input signal and the output signal in 59-1.

  As a result, the voltage presence / absence detection means 59-1 outputs the first no-voltage signal D which is an identification signal indicating no voltage when the IPL signal is Low, that is, when there is no output voltage of the AC power supply 52. Here, if the power supply frequency of the AC power supply 22 is 50 Hz, for example, the time of one cycle is 20 milliseconds, so the first voltage-less signal D is when the output voltage of the AC power supply 52 is not more than 10 milliseconds. Is output.

  The first timer 60 is a timer that sets a first set time T1 that is a limit time from the time when the AC power supply 52 starts to fail to the time when it is regarded as a temporary instantaneous power failure. That is, the set time T1 refers to a time that can be regarded as a range in which the AC power supply 52 operates normally even if a power failure occurs.

  The first signal discriminating means 61 receives the first no-voltage signal D, and the first no-voltage signal D is present within the first set time T 1 set by the first timer 60. It is a discriminator for discriminating whether or not to return to a signal. When the inputted first no-voltage signal D does not return within the first set time T1, the second no-voltage signal E, which is the no-voltage identification signal, is output to the second signal discrimination means 62. Further, when the input first no-voltage signal D returns within the first set time T1, a signal indicating that the power supply is normal is output.

  The second timer 62 is a time that exceeds the first set time T1 and supplies power to the fuse blown and instantaneous power failure detection device 58-1 after the power failure from the time when the AC power supply 52 starts to fail. This is a timer for setting a second set time T2, which is a limit time until the time when the operation of the control power supply 56 can be continuously maintained. That is, the set time T2 is a time for determining that the fuse 53 is blown or that there is a momentary power failure.

  The second signal discriminating means 63 is a second no-voltage discrimination signal that is output when the first signal discriminating means 61 does not return the first voltageless signal D within the first set time T1. A discriminator for inputting a no-voltage signal E and discriminating whether or not the second no-voltage signal E returns to a signal with a voltage at the second set time T2 set by the second timer 62. is there. When the input second no-voltage signal E does not return to the second set time T2, it is determined that the fuse 53 has blown, and a fuse blow detection signal is output. Further, when the input second no-voltage signal E returns to the second set time T2, it is determined that an instantaneous power failure has occurred, and an instantaneous power failure detection signal is output.

  Next, the fuse blown and instantaneous power failure detection processing procedure in the fuse blown and instantaneous power failure detection device 58-1 according to the present invention will be described with reference to FIG. As shown in FIGS. 1, 3, and 6, the processing procedure for detecting the blown fuse and the instantaneous power failure includes the secondary side terminal of the fuse 53 connected to one terminal R of the AC power source 52 and the other side of the AC power source 52. The first voltage no signal D is output when there is no AC voltage based on the result of detecting the presence or absence of the AC voltage. That is, a first step (S-1) for detecting the presence / absence of an AC voltage by the voltage presence / absence detection means 59-1, and a first no-voltage signal D by the gate signal on / off selector 57, As a temporary instantaneous power failure process, the second step (S-2) for shutting off the gate of the switching element by the switching circuit 54 and the first signal determining means 61 input the first no-voltage signal D, A third step of determining whether or not the first voltageless signal D returns to a signal with a voltage (High) within a first set time T1 by the first timer 60; When the first voltage absence signal D returns to the voltage presence signal at the first set time according to the result of the third step, the AC power supply 52 determines that there is no abnormality. 4th Sustained Driving (S-4) and the second signal discriminating means 63, when the first voltage absence signal D does not return to the voltage presence signal within the first set time T1 according to the result of the third step. The second voltage absence signal E to be output is input, and the second voltage absence signal E is returned to a signal with voltage (High) at the second set time T2 by the second timer 62 (Low). ) By the fifth step (S-5) and the second signal discriminating means 63, when the second voltage-less signal E is returned to the voltage-present signal by the result of the fifth step, A sixth step (S-6) for determining that the AC power supply 52 has momentarily stopped and outputting a momentary power failure detection signal and a second signal determining means 63 to determine the second voltage based on the result of the fifth step. When no signal E returns to a voltage signal, it is determined that the fuse is blown. , Comprising a seventh step of outputting the fuse blow detection signal (S-7).

[Operation]
Next, the operation of the fuse blown and instantaneous power failure detection device 58-1 according to the present invention will be described. FIG. 7 is a diagram showing the relationship between the AC power source waveform, the square wave waveform, and the IPL signal waveform when there is a momentary power failure with respect to the elapsed time in the fuse blown and momentary power failure detection device 58-1 according to the present invention. FIG. 7A is a diagram showing input voltage waveforms (A and B shown in FIGS. 1, 3 and 4) of the fuse blown and instantaneous power failure detection device with respect to the elapsed time when the AC power supply 52 fails. Indicating the horizontal axis represents the time elapsed after t, the vertical axis represents the input voltage V _AC, respectively. FIG. 7B is a diagram illustrating a square-wave voltage waveform formed from the input voltage waveform with respect to elapsed time when the AC power supply 52 fails as in FIG. 7A. The horizontal axis represents the elapsed time t, and the vertical axis represents the DC voltage _VDC of the square wave signal formed from the input voltage waveform. FIG. 7C shows the timing of the IPL signal (D shown in FIGS. 1, 3 and 4) with respect to the elapsed time. The horizontal axis represents the time elapsed after t, the vertical axis of the IPL signal, voltage absence signal which is a signal without a voltage V _IPL (Low) or voltage presence signal voltage V _IPL is a signal there either the (High) Signal timing is shown respectively.

  The input voltage waveform (corresponding to the output voltage waveform of the AC power supply 52) of the fuse blown and instantaneous power failure detection device 58-1 is, as shown in FIG. 7A, at an arbitrary time t1 after the elapse of time T0. When a power failure occurs and the time T passes after the time T has elapsed, when the power failure is restored, it indicates that the level of the input voltage is missing from the time t1 to the time t2. Here, when the AC power source 52 is, for example, a 50 Hz single-phase AC power source, one cycle corresponds to 20 milliseconds. The square wave waveform formed from the AC input voltage waveform is composed of a DC component by the voltage presence / absence detection means 59-1. As shown in FIG. 7C, the IPL signal is a signal that is output as a no-voltage signal D in a section from time t1 to time t2 when the AC power supply 52 is instantaneously stopped and then restored. Here, when the AC power supplied to the load 55 by the AC power source 52 is continuously cut off for a period of ½ cycle or more, the IPL signal is a signal that determines that the voltage of the AC power source 52 is absent (Low). Become. In other words, if the AC power interruption period by the AC power supply 52 is less than ½ cycle, the IPL signal is a signal that determines that the voltage of the AC power supply 52 is high.

FIG. 8 is a diagram showing the timings of the first set time and the second set time with respect to the elapsed time and the discharge time of the control power source 56 with respect to the elapsed time in the fuse blown and instantaneous power failure detection device 58-1 according to the present invention. The horizontal axis represents the elapsed time t, and the vertical axis represents the output voltage V _IPL of the IPL signal or the output voltage V of the control power source 56, respectively. The time T1 indicates a first set time that is a limit time from the time t1 when the AC power supply 52 is interrupted to the time t2 that can be regarded as a temporary instantaneous power failure. Here, the provisional momentary power failure means a momentary power failure that the AC power supply 52 considers as the normal operating range even if a power failure occurs. That is, the time T1 indicates a time when a power failure occurs at time t1 and the power failure returns within the normal operation range. The time T2 is a time exceeding the first set time, and the operation of the control power source 56 that supplies power to the fuse blown and instantaneous power failure detection device 58-1 from the time when the AC power source 52 is cut off continues. The second set time, which is the limit time until the time that can be maintained, is shown.

  FIG. 8A shows the timing of the output waveform of the IPL signal with respect to the elapsed time t when the instantaneous power interruption time T (hereinafter referred to as the instantaneous power interruption time) is 0 ≦ T ≦ T1. FIG. 8B shows the timing of the output waveform of the IPL signal with respect to the elapsed time t when the instantaneous power interruption time T is T1 <T ≦ T2. FIG. 8C shows the timing of the output waveform of the IPL signal with respect to the elapsed time t when the instantaneous power interruption time T is T2 <T. FIG. 8D shows the relationship between the second set time T2 and the output voltage of the control power supply 56 with respect to the elapsed time t. As shown in FIG. 1, the control power supply 56 is supplied with power from the AC power supply 52, so that when the AC power supply 52 is interrupted, the input is completely cut off. The capacitor continues to supply power to the fuse blown and instantaneous power failure detection device 58-1 for a discharge time (corresponding to the second set time T 2) corresponding to the capacitance of the storage capacitor. Here, for example, the first set time T1 is 0.5 seconds, and the second set time T2 is 1.5 seconds. If the power supply frequency of the AC power supply 22 is, for example, 50 Hz, the time of one cycle is 20 milliseconds, and therefore the presence or absence of voltage after 25 cycles and 75 cycles is detected.

  Further, the first voltage absence signal D of the IPL signal from the voltage presence / absence detection means 59-1 is input to the first signal discrimination means 61, and the first signal discrimination means 61 performs the first signal by the first timer 60. When the voltage does not return within the set time T1, the second no-voltage signal E is output to the second signal discriminating means 63. When the second no-voltage signal E is input to the second signal discriminating means 63 and the voltage is restored (high) by the second signal discriminating means 63 to the second set time T2 by the second timer 62. Then, it is determined that the AC power supply 52 has instantaneously stopped, and an instantaneous stop detection signal is output. When the voltage does not recover (Low), it is determined that the fuse has blown, and a fuse blow detection signal is output.

  On the other hand, using the first no-voltage signal D, the second no-voltage signal E, and the gate source signal F, it is possible to control to turn on or off the gate of the switching element of the switching circuit 54. That is, first, when the first voltage absence signal D by the voltage presence / absence detection means 59-1 is input to a logic circuit 65, for example, an AND circuit, as shown in FIG. 2, there is no voltage as a gate signal C by the AND circuit. Output a signal. Thereby, the switching circuit 54 can input the gate signal C for controlling the gate of a switching element, and can turn off a gate. Therefore, the AC power supply 52 can be temporarily subjected to instantaneous power failure processing.

  Next, when the second no-voltage signal E by the first signal discriminating means 61 is input to the latch circuit 64 by the gate signal on / off selector 57, as shown in FIGS. The absence signal E is held, and a latch signal G which is a no-voltage signal is output to the logic circuit 65. When the latch signal G is input to the logic circuit 65, for example, an AND circuit, the AND circuit outputs a no-voltage signal as a gate signal. Thereby, the switching circuit 54 can input the gate signal C for controlling the gate of a switching element, and can turn off a gate. Therefore, the AC power supply 52 can be shut off.

  Further, when the first signal discriminating means 61 returns the voltage within the first set time T 1 by the first timer 60 (High), a first voltage present signal (not shown) is sent to the logic circuit 65. Output. In this case, since the output voltage of the first signal discriminating means 61 is restored, the output voltage of the voltage presence / absence detecting means 59-1 should also be restored. If a first voltage presence signal (not shown) and the first signal presence signal by the first signal discriminating means are input to a logic circuit 65, for example, an AND circuit, a signal with a voltage is output by the AND circuit. Thereby, the switching circuit 54 can input the gate signal C for controlling the gate of the switching element, and can turn on the gate. Therefore, the operation of the AC power supply 52 can be continued.

  As described above, according to the present invention, the fuse blown and instantaneous power failure detection device 58-1 includes the voltage presence / absence detection means 59-1, the first timer 60, the first signal determination means 61, the second timer 62, and the second timer 62. Second signal discriminating means 63, and the first signal discriminating means 61 causes the first no-voltage signal D from the voltage presence / absence detecting means 59-1 to generate a voltage within the first set time T1 by the first timer 60. When returning to a signal with voltage at the second set time T2 by the second timer 62 without returning to a signal with presence, the second signal discrimination means 63 determines that there is a momentary interruption and detects momentary interruption. When a signal is output and the signal with voltage is not restored at the second set time T2 by the second timer 62, it is determined that the fuse is blown, and a fuse blown detection signal is output. As a result, the detection of blown fuse and the detection of instantaneous interruption can be realized by a single circuit, and therefore, space saving and improved reliability can be achieved as compared with the case of separate circuit configurations.

  In the above description, in order to detect a blown fuse and an instantaneous power failure, an example in which a square waveform formed by half-wave rectification from the AC power supply 52 is applied. However, the present invention is not limited to this. A square waveform obtained by full-wave rectification from the power supply 52 may be applied.

  Furthermore, the AC power source 52 is not limited to a single-phase AC power source, and can also be applied to a three-phase AC power source. In this case, unlike the case of the heating power supply device 51, the heating power supply device 51-2 using the three-phase AC power supply basically has an output terminal of each phase of the three-phase AC power supply and a fuse blown / instantaneous power failure detection device 58. 2, a fuse 53, a three-phase switching circuit, and a fuse blown / instantaneous power failure detection device 58-2. The fuse blown / instantaneous power failure detection device 58-2 includes a voltage presence / absence detection device 59-2 instead of the voltage presence / absence detection device 59-1 provided in the fuse blown / instantaneous power failure detection device 58-1. The voltage presence / absence detection means 59-2 is an electric circuit that detects whether or not there is an output voltage from the three-phase AC power supply, as in the case of the single-phase AC power supply. As shown in FIG. 5, the square wave generator 66- 2. A logic circuit 74 and a voltage level detector 67 are provided.

  The square wave generator 66-2 includes the same three circuits as the square wave generator 66-1 provided in the voltage presence / absence detecting means 59-1 shown in FIG. The square wave generator 66-2 receives line AC voltages between the RS, ST, and TR terminals from a three-phase AC power supply, and has three types of square wave signals K1 whose phases differ from each other by 120 degrees. , K2, K3 are output to the logic circuit 74. Here, R, S, and T indicate three-phase terminals in the AC power supply 52. The logic circuit 74 is a NAND circuit, for example. The NAND circuit receives the three types of square wave signals K1, K2, and K3 from the square wave generator 66-2, and outputs a High signal when the output voltage of the three-phase AC power supply is present, as a result of the operation by the NAND circuit. When there is no output voltage of the three-phase AC power supply, a Low signal is output. As in the case of the voltage presence / absence detecting means 59-1 shown in FIG. 4, the voltage level detector 67 receives the Low signal, and the filter circuit 72 and the comparator 73 cause the first no-voltage signal which is a Low signal. D is output.

  Therefore, the voltage presence / absence detection means 59-2 outputs the first voltage absence signal D which is a Low signal when there is no output voltage of the three-phase AC power supply. In other words, when the output voltage of the three-phase AC power supply is present, the NAND circuit outputs a continuous high signal, so that the three-phase AC power supply is within ½ cycle of each phase (for example, when the power supply frequency is 50 Hz) Even when the ½ cycle is cut off within 10 milliseconds), unlike the case of the single-phase AC power supply, the first no-voltage signal D that is a Low signal can be detected as the IPL signal. As a result, in the case of a three-phase AC power source, it is possible to detect a blown fuse and detect an instantaneous power failure even for a momentary power failure that occurs in a shorter time than a single-phase AC power source.

  In addition, the present invention is applied to a heating power supply device as an example of the embodiment, but is not limited thereto, and can be applied to a resistor, an electric motor, and the like that operate by supplying power from an AC power supply.

It is a schematic control block diagram at the time of applying the fuse blown and instantaneous power failure detection device according to the present invention to a heating power supply device. FIG. 2 is a supplementary explanatory diagram of FIG. 1. It is a control block diagram which shows the fuse blown and instantaneous power failure detection apparatus which concerns on this invention. It is a control block diagram which shows the voltage presence-and-absence detection means in the fuse blown and instantaneous power failure detection device according to the present invention. It is a control block diagram which shows the other voltage presence-and-absence detection means in the fuse blown and instantaneous power failure detection device according to the present invention. It is a figure which shows the process sequence of the detection of the fuse blow and instantaneous stop in the fuse blow and instantaneous stop detection apparatus which concerns on this invention. It is a figure which shows the relationship between an alternating current power supply waveform, a square wave waveform, and a 1st operation signal waveform when there exists a momentary power supply with respect to the elapsed time in the fuse blown and instantaneous power failure detection device according to the present invention. It is a figure which shows the timing of the electrical storage time of the 1st setting time with respect to the elapsed time in the fuse blown and instantaneous power failure detection apparatus which concerns on this invention, 2nd setting time, and the power supply for control. It is a control block diagram which shows the conventional fuse blow detection apparatus. It is a control block diagram which shows the conventional instantaneous power failure detection apparatus.

Explanation of symbols

51 Heating Power Supply Device 52 AC Power Supply 53 Fuse 54 Switching Circuit 55 Load (Heating Power Supply Unit)
56 control power supply 57 gate signal on / off selector 58-1 fuse blown and instantaneous power failure detection device 59-1, 59-2 voltage presence / absence detection means 60 first timer 61 first signal determination means 62 second timer 63 Second signal discriminating means 64 Latch circuit 65 Logic circuit 66-1, 66-2 Square wave generator 67 Voltage level detector 68 Current limiting resistor 69 Diode 70 Photocoupler 71 Voltage detecting resistor 72 Filter circuit 73 Comparator 74 Logic circuit 75 Logic circuit A, B AC voltage signal C Gate signal D First voltage no signal E Second voltage no signal F Gate source signal G Latch signal

Claims (3)

In a power supply apparatus in which a fuse and a switching element for turning on or off the AC power are connected to a wiring path for supplying AC power from an AC power source to a load, the fuse is blown and the AC power is instantaneously interrupted. A device,
A voltage presence / absence detecting means for outputting a first no-voltage signal, which is an identification signal indicating no voltage, when an AC voltage is not present according to a result of detecting the presence / absence of the AC voltage by inputting an AC voltage of the AC power source;
A first timer for setting a first set time which is a limit time from a time at which the AC power supply starts to fail to a time at which it is regarded as a temporary instantaneous power failure;
A time exceeding the first set time and a time at which the operation of the control power supply for supplying power to the fuse blown and instantaneous power failure detection device after the power failure can be continuously maintained from the time when the AC power source starts to fail. a second timer for setting the second set time is a limit time until,
The first no-voltage signal is input, it is determined whether or not the first no-voltage signal returns to a signal with a voltage within the first set time, and the first no-voltage signal is A first signal discriminating means for outputting a second no-voltage signal that is an identification signal without voltage when it is discriminated that the signal does not return to a signal with voltage;
A second no-voltage signal is input from the first signal discriminating means, and it is discriminated whether or not the second no-voltage signal returns to a signal with a voltage at the second set time, When the no-voltage signal 2 returns to the signal with voltage at the second set time, it is determined that the AC power supply has instantaneously failed, and an instantaneous power failure detection signal is output. And a second signal discriminating means for determining that the fuse of the AC power supply has blown and outputting a fuse blow detection signal when the signal does not return to a signal with voltage during the set time. Instantaneous power failure detection device.   2. The fuse blown and instantaneous power failure detection device according to claim 1, wherein the load is a heating power supply unit. A wiring path for supplying AC power from an AC power source to a load, a fuse and a switching element for turning on or off the AC power are connected, and a device for detecting fusing of the fuse and an instantaneous power failure of the AC power; and A fuse blown and instantaneous power failure detection method in a power supply device comprising a control power supply for supplying power to a fuse blown and instantaneous power failure detection device,
A first step of inputting an AC voltage of the AC power source and outputting a first no-voltage signal that is an identification signal indicating no voltage when there is no AC voltage as a result of detecting the presence or absence of the AC voltage;
A second step of tentatively blocking the gate of the switching element as a temporary instantaneous power failure process by the first no-voltage signal;
Whether or not the first no-voltage signal returns to a signal with voltage within a first set time, which is a limit time from the time when the AC power supply starts to fail to the time when it is regarded as a temporary instantaneous power failure. A third step of determining;
When the first no voltage signal returns to the voltage present signal as a result of the third step, the AC power source is determined to be normal and the fourth step of continuously operating the power source device;
As a result of the third step, the second no-voltage signal is generated by the second no-voltage signal which is the identification signal without voltage that is output when the first no-voltage signal does not return to the signal with voltage. The operation of the control power source that supplies power to the fuse blown and instantaneous power failure detection device after the power failure can be continuously maintained from the time when the AC power source starts to fail after the first set time is exceeded. A fifth step of determining whether or not to return to a signal with voltage at a second set time which is a limit time until the time;
According to the result of the fifth step, when the second signal without voltage returns to the signal with voltage, the sixth step determines that the AC power supply has instantaneously failed and outputs an instantaneous power failure detection signal;
A seventh step of determining that the fuse of the AC power supply is blown and outputting a fuse blown detection signal when the second no-voltage signal does not return to the voltage-loaded signal according to the result of the fifth step; A fuse fusing and instantaneous power failure detection method comprising:

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