JP2656532B2 - Electric circuit state detecting device and electric device using the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure detection circuit in a contact contactor in a contact welding or a conduction state of a main circuit element in a solid state contactor, and particularly to an abnormality in a wide range of load voltage. The present invention relates to a failure detection circuit suitable for detection.

[Conventional technology]

As described in Japanese Patent Application Laid-Open No. Sho 61-220221, a conventional device is configured to detect a mismatch between a control voltage and a load side voltage and to output an output signal when a mismatch occurs.

[Problems to be solved by the invention]

The above prior art does not consider using a failure detection circuit in a wide voltage range.For example, if a failure detection circuit is used for a 200V circuit for a 100V circuit, the control voltage and the load side voltage will not match even if both are normal. There is a problem that the product cannot be shared because it is regarded as a state.

An object of the present invention is to provide an electric circuit state detecting device which can be used in a wide voltage range, for example, can share a product even at different voltages of 100 V and 200 V, and an electric device using the same.

[Means for solving the problem]

The above object is to provide a circuit state detecting device that detects a voltage of a three-phase circuit, generates and holds a first voltage substantially proportional to a normal voltage, and a current holding circuit that detects a current of the circuit. Voltage generating means for generating a second voltage substantially proportional to the voltage, comparing means for comparing the first voltage with the second voltage, and judging means connected to be supplied with the output of the comparing means The comparing means generates a signal indicating that the electric circuit is ON when the ratio of the second voltage value to the first voltage value is at a high level, and compares the second voltage value with respect to the first voltage value. When the ratio is low, a signal indicating that the circuit is OFF is generated, and the determining means determines that the circuit is normal when the ratio of the second voltage value to the first voltage value is high and low. It is determined that the ratio of the second voltage value to the first voltage value is a medium level. Path is achieved by configured to determine that an abnormality.

[Action]

The comparing means provided in the circuit state detecting device compares the first voltage based on the maximum voltage of the circuit with the second voltage based on the voltage of the circuit, and compares the second voltage with the first voltage. Then, it is determined whether the ratio is equal to or more than a predetermined ratio to determine the ON / OFF state of the electric circuit. Thus, even if the voltage of the electric circuit is different, ON / OFF can be determined at a ratio to the voltage. In addition, 1 of electric circuit
When the phase is in a non-conductive state, an output having a waveform different from that in the ON state is generated.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

The electric circuit state detecting device according to the first embodiment of the present invention
This will be described with reference to FIGS.

The circuit state detecting device of the present embodiment includes a rectifier circuit 10 connected to the three-phase circuit 1, a power circuit 12 connected to the rectifier circuit 10 to generate a substantially constant power supply voltage VCC, and an output voltage of the rectifier circuit 10. And a voltage attenuation detection circuit 14 to which a power supply voltage VCC is supplied from the power supply circuit 12. The rectifier circuit 10 is a well-known three-phase bridge circuit formed by combining diodes D1 to D6. The power supply circuit has a Zener diode ZD1 for generating a reference voltage, an additional resistor R1 of the Zener diode ZD1, a base connected to the anode of the Zener diode ZD1, a collector connected to the positive output of the rectifier circuit, and an emitter connected to the diode D7. And a transistor Q1 connected to the negative output of the rectifier circuit via the capacitor C1. The power supply circuit 12 is configured to obtain the output from the anode side of a diode D7 connected to the emitter of the output VCC transistor Q1 in the forward direction. The voltage decay detecting circuit 14 is a voltage dividing circuit 10 as a voltage generating means comprising resistors R2 and R3 connected in series.
A voltage holding circuit 12 as voltage holding means including a diode D8 connected in series, resistors R4, R5 and a capacitor C2 connected in parallel with the resistor R5, and a resistor R of a voltage dividing circuit.
2, The voltage divided by R3 and the resistance R of the voltage holding circuit
4 and the voltage divided by R5 and the comparator Q2. The comparator Q2 receives the power supply voltage from the power supply circuit 12.
VCC is supplied, and the voltage V1 divided by the resistors R2 and R3 of the voltage divider circuit is input to the plus side input, and the resistors R4 and R5 of the voltage holding circuit are
The voltage V2 divided by the above is supplied to the minus input. As a result, when the voltage V1 supplied from the voltage dividing circuit exceeds the voltage V2 supplied from the voltage holding circuit as shown in FIG. When the three-phase AC voltage is normally applied and removed, the output V3 of the comparator Q3 becomes a pulse train having a substantially constant period as shown in FIG. 2 (B). Now, assuming that the output voltage of the rectifier circuit 10, that is, the voltage V0 at the point A and the forward voltage drop of the diode D8 is VD, V1 is the voltage value across R3 when V0 is divided by R2 and R3, and V2 Is the time constant C2R5 with the peak value of the voltage across R5 when V0-VD is divided by R4 and R5.
Becomes a value that decreases exponentially. Since the forward voltage drop VD of the diode D8 is usually about 0.8 V, the V0 value is large and V0
Is negligible, V2 is a value that decreases exponentially with a time constant C2R5 with the voltage value across R5 as a peak when V0 is divided by R4 and R5.

Therefore, the voltage decay detection circuit 14 outputs the rectifier circuit output voltage V0
H1 is output when V1> V2 holds regardless of the above.

As a result, as shown in FIG.
Drop faster than the discharge time constant of
Remain at the L level.

Thus, even if a load such as a motor that generates a residual voltage is connected to the electric circuit 1, the ON / OFF state of the electric circuit 1 can be determined.

When there is an open phase in the electric circuit 1, the output of the rectifier circuit 10 has a large ripple as shown in FIG.
Generates a pulse train having a different cycle and a different duty ratio from the normal state. As a result, the circuit state detecting device of the present embodiment has a normal circuit without being affected by the circuit voltage.
It can be determined whether it is in the ON state or the open phase state. In order to make this determination electrically, as an example, the output V3 is integrated by a resistor R6 and a capacitor C3 and converted into a high or low voltage, and this voltage is converted to a high level, a medium level, or a low level by comparators Q3 and Q4. What is necessary is just to judge whether it is a level. The determination means 16 is configured as described above,
The normal or abnormal state of the electric circuit can be determined by the high level output in the ON state, the low level output in the OFF state, and the medium level output in the open phase state. The voltage divided by the resistors R7 and R8 is set to be higher than the voltage divided by the resistors R9 and R10. Q5 is an AND circuit, and Q6 is a NOT circuit.

A second embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the present invention is applied to a failure detection circuit of an electronic contactor.

The fourth shows a block diagram of an electronic contactor provided with a failure detection circuit according to the present embodiment, which is composed of an input circuit 121 connected to an input terminal 105, and a control circuit 12 of the next stage.
2. The trigger circuit 123 and the delay circuit 124 connected to the control circuit 122, and the main circuit element 125 activated by the trigger circuit 123.
And a rectifier circuit 1 for rectifying the load side voltage
41, internal circuit power supply circuit 142, and load-side voltage attenuation detection circuit 1
43, a smoothing circuit 144 driven by the signal states of the delay circuit 124 and the detection circuit 143, and a failure detection circuit including a next-stage drive circuit 145.

 The main part of this embodiment will be described with reference to FIG.

The rectifier circuit 141 is connected to each phase of the electric circuit, takes in the voltage of the electric circuit, rectifies the voltage, and rectifies the power circuit 142 and the attenuation detection circuit 143.
To supply. The power supply circuit 142 is a constant voltage circuit, and the rectifier circuit 141
From the voltage supplied from
C is supplied to the failure detection circuit 143 and the relay 108.

The voltage attenuation detection circuit 143 includes resistors 172 and 173 for dividing the output of the rectifier circuit 141, an amplifier 171 having a non-inverting input terminal connected to the voltage dividing point, and a diode 174 connected to an output terminal of the amplifier 171. , A capacitor 176 connected to a series circuit of a resistor 175, and a capacitor 17 formed of a parallel circuit of a resistor 177.
6 comprises a peak hold circuit having a positive electrode connected to the inverting input terminal of the amplifier 171 and an amplifier 178 connected to the output terminal of the amplifier 171 and operated as a voltage follower which is negatively fed back so as to have a gain of 1. ing. The smoothing circuit 144 includes a diode 179, a resistor 180, and a capacitor 181 connected in series, and the delay circuit 124 is connected in parallel to a known delay circuit and a photocoupler light emitting unit 107a connected to the output thereof, and a capacitor 181 of the smoothing circuit 144. It comprises a series connection circuit of the resistor 182 and the light emitting unit 107b.

The drive circuit 145 includes a transistor 163 having a base connected to the positive electrode of the capacitor 181 of the smoothing circuit 144 via a resistor 160.
And a capacitor 161 and a resistor 162 connected in parallel to the load between the base and the emitter of the transistor 163, respectively.
The collector of the transistor 163 of the drive circuit 145 is connected to the output terminal 106 of the failure detection circuit, and the output terminal 106 is connected to the relay 108.
And a series circuit of a resistor 164 and a diode 165 connected in parallel with the series circuit and serving as a flywheel circuit.

Next, the operation will be described. The English characters in the waveforms of FIG. 6 indicate the waveforms of the English characters in the circuit diagram of FIG.

When the main circuit element 125 is operating normally, the amplification period 171 of the attenuation detection circuit 143 is performed when the voltage of the non-inverting input terminal exceeds the voltage of the inverting input terminal for each ripple of the rectified waveform of the rectifying circuit 141. Generate output. As a result, the D section outputs a pulse as shown in FIG.
Since the output of 2 is at the H level, the light emitting portion of the photocoupler 107
Since the light 107a emits light and the light receiving section 107b conducts and current is sunk, the waveform of the section E becomes L level as shown in FIG. As a result, the output of the smoothing circuit 144 becomes L level, the transistor 163 of the driving circuit 145 connected thereto becomes non-conductive, the relay 108 is not excited, and the main circuit element 125 is in a normal state.

Next, when an off signal (H → L in FIG. 6 (a)) is output from the control circuit of the contactor 125 that is operating normally, the voltage at the portion A is attenuated. At this time, if a load that generates a residual voltage such as an electric motor is connected to the load side of the electric circuit 101,
For example, the load side voltage of the electric circuit 101 is attenuated as shown in (a), and after the release time delay, the output of the delay circuit is changed from H to L as shown in (c).

As a result, the photocoupler light receiving unit 107b is turned off, but no pulse is output from the D portion, and the potential of the capacitor 181 remains at the L level as shown in the waveform (e) of the E portion. Accordingly, the relay 108 connected to the detection circuit output terminal 106 is not excited, and indicates whether the main circuit element 125 is in a normal state.

Next, a case where the main circuit element 125 has failed will be described. When a semiconductor element is used as the main circuit element 125, a short-circuit mode failure occurs when a current exceeding the rating flows. In the case of three phases, when a short circuit fault occurs in only one element, the load 103 is normally turned on and off by the other two elements, so that safety can be ensured.

Next, when two of the main circuit elements 125 are short-circuited, current continues to flow to the load 103 in an open phase state through the failed two elements even if the remaining normal one is turned off, resulting in a dangerous state. There are cases.

In this case, when an off signal (H → L in FIG. 6 (a)) is output from the control circuit 122, the voltage at the portion A has an open-phase (single-phase) waveform as shown in (f). After the delay time, when the output of the delay circuit becomes L level as shown in (c), the photocoupler light emitting unit 107a is turned off and the photocoupler light receiving unit 107b is turned off. As a result, the capacitor 181 of the smoothing circuit 144
Is in a chargeable state, the pulse waveform shown in FIG. 6G supplied from the voltage decay detection circuit 143 is charged to the capacitor 181 via the resistor 180, and the capacitor is charged as shown in FIG. The potential of the positive electrode 181 increases. As a result, the transistor 163 of the drive circuit 145 is turned on, and the relay 10 is turned on.
The coil 8 is excited to indicate that the main circuit element 125 is in a fault state. Although not shown, the relay 108 is provided with a contact. When using a normally open tangent as an example,
The normally open contact may be connected to a magnetic trip device of a circuit shield (not shown) provided at a higher position, and the circuit may be interrupted by the circuit breaker when a failure is detected. When a normally closed contact is used as an example, the normally closed contact may be connected to a coil of an electromagnetic contactor provided at an upper position, and the circuit may be shut off by the electromagnetic contactor when a failure is detected. In addition, using these contacts, an indicator lamp may be turned on or a buzzer lamp may be used to issue an alarm if necessary.

According to the present embodiment, there is no need to set a delay time,
Moreover, the operation can be performed at the first peak of the load voltage at the time of the short-circuit failure, so that the operation speed is high. Also, do not use a fixed setting voltage such as a Zener diode. Since the normal voltage is used as the reference voltage, there is an effect that high-speed operation can be performed with respect to a wide voltage range of, for example, 100V to 200V. When the zener voltage is used as the reference voltage, the time required for the load voltage to attenuate to the reference voltage in the event of a failure differs depending on the voltage class, so that it can only handle a narrow range of voltages. I can't get it.

 A modification of this embodiment will be described with reference to FIGS.

 FIG. 7 shows a first modification of the present embodiment.

In this modification, the smoothing circuit 144 in FIG. The latch circuit 146 may use a well-known thyristor, latch IC, or the like. This makes it possible to eliminate variations in operating time due to variations in capacitor capacitance, and to obtain accurate operating characteristics.

 FIG. 8 shows a second modification of the present embodiment.

In this modification, a comparator 182 is added to the smoothing circuit 144. According to this modification, since the input is a high impedance, the ripple of the capacitor 181 is reduced.

 FIG. 9 shows a third modification of the present embodiment.

In this modification, the voltage attenuation detection circuit itself has a delay characteristic, and a similar function is obtained without using the delay circuit 124. The voltage attenuation detection circuit 148 in this modification transmits the ON signal and the OFF signal of the control circuit 122 to the power supply attenuation detection circuit 148 via the photocoupler 107, and the analog switch 190 is turned on or off by this signal. Then, this state is transmitted to another analog switch 191 via a differentiating circuit connected in series with the analog switch 190 to obtain a delay.

When an ON signal is output from the control circuit 122, the analog switch 190
C terminal becomes LOW, and between i-o becomes non-conductive.
Since the C terminal of the analog switch 191 also becomes LOW and becomes non-conductive between i and o, the capacitor of the next stage peak hold circuit
176 is charged to the peak voltage of the resistor 173.

Next, when an OFF signal is output from the control circuit 122, the C terminal of the analog switch 190 becomes High, and conduction is performed between i and o. Therefore, the c terminal of the analog switch 191 is connected to the differential circuit capacitor 194, the resistors 193, and 195. , The potential gradually decreases from the high level, and goes low after a certain period of time according to the time constant of the differentiating circuit. Accordingly, between i and o of the analog switch 191, conduction is performed when the terminal c is high, that is, the non-inverting input terminal of the comparator 171 is almost 0, so that the potential of the capacitor 181 at the next stage becomes almost 0, and The output of the voltage decay detection circuit can be delayed until becomes nonconductive.

According to the present embodiment, regardless of the load voltage, the three-phase two-element short-circuit, the three-phase three-element short-circuit, and the decay characteristic of the load residual voltage, the short-circuit failure detection is always performed at the first peak of the load voltage after the release time delay. Therefore, the present invention can be applied to a wide range of voltages, for example, common use of 100 V and 200 V, and has an effect of achieving a general-purpose failure detection circuit that can operate at high speed without adjustment for various loads.

A third embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the present invention is applied to a reversible electronic contactor.

A conventional failure detection device detects a short-circuit failure of an element when a load voltage and a conduction signal do not match, as described in Japanese Utility Model Application Laid-Open No. 61-157214, for example. However, no consideration is given to failure detection of the reversible electronic contactor, and when this is simply applied to the reversible electronic contactor, for example, during forward rotation, the reverse contactor has a non-conductive input. However, since the power supply voltage is substantially applied to the load voltage, when the failure detection circuit is built in the reverse contactor, there is a problem that a signal indicating a failure is generated even if it is normal. .

In the present embodiment, when a failure detection circuit is installed in a contactor with a built-in failure detection circuit or each contactor, the operation of the failure detection circuit of the non-conduction contactor is prohibited by the signal of the conduction contactor ( Lock), or a failure is detected by the logical sum output of normal rotation and reverse rotation and the logic of the load voltage (there is an output of the logical sum, the open fault occurs when the load voltage is zero, and the short-circuit fault occurs when the load voltage is reverse). Thus, a failure detection circuit applicable to a reversible electronic contactor can be obtained.

FIG. 10 shows an internal block diagram and a reversible connection of the solid state contactor having a built-in failure detection circuit according to the present embodiment. Since the forward contactor 201 and the reverse contactor 202 have the same configuration, the forward rotation will be described. The power supply circuit 280 supplies power to the input circuit 281 and the control circuit 282. The input circuit 281 is composed of, for example, a circuit for smoothing a ripple in an AC input. Control circuit 282
Determines whether the input signal is within a predetermined voltage range, and determines the operation or non-operation of the subsequent circuit. Control circuit 282
One output of the main switching element 288 is turned on through a gate circuit 283, and the other output is turned on and off by a delay circuit 284 to output a failure detection circuit 285, a reversible interlock circuit 287, and a failure detection interface. The signal is transmitted to the lock circuit 286.

Now, assuming that the forward rotation switch 206 is turned on, the reversible interlock circuit 287 locks either the input circuit 291 or the control circuit 292 or the gate circuit 293 of the reverse contactor 202 via the terminals 213 and 224. Thereby, the reverse contactor 202 becomes non-conductive. Further, the failure detection interlock circuit 286 locks the failure detection circuit 295 via the terminals 212 and 226, so that only the forward contactor 201 operates.

FIG. 11 shows an internal circuit of the forward contactor 201. The failure detection circuit 285 is connected to the delay circuit via the photo coupler 217. Note that D203 to D208 in the failure detection circuit 285.
Is a diode for rectification, RY201 is a relay, common contact 215
c, a normally open contact 215a, and a normally closed contact 215b.

In FIG. 11, R201 to 211 are resistors, D201 diode bridge, D202 to D208 are diodes, C201 to C203 are capacitors, Q201 is a transistor, Q202 is a comparator, Q203 is an inverting circuit, Q204 is a buffer, and Q205 to Q209 are Photocouplers, 211a and 211b are control signal input terminals, 214a and 214b are interlock signal input terminals from the reversible interlock circuit of the reverse contactor, 212a and 212b are failure detection interlock circuit output terminals, 213a and 213b. Is an output terminal of the reversible interlock circuit, and 216a and 216b are output terminals of a signal for locking the failure detection circuit of the reverse contactor to an inoperative state. 283a, 283b, 283c are switching elements 28 of each phase of the electric circuit.
8 gate circuits.

According to the present embodiment, even in the case of the solid state contactor with a built-in failure detection circuit, the reversible type locks the other failure detection circuits with each other, so that there is no erroneous detection.

FIG. 12 and FIG. 13 are views showing a mounting diagram of the present embodiment, in which interlock signal transfer terminals 212a, 212b, 213a, 213b, 21
4a, 214b, 216a, and 216b are receptacles 215 for mounting on a printed circuit board, and the other receptacle is a flat cable 253.
Connect with 252.

According to this embodiment, the non-reversible type can be used alone as it is, and the reversible type can easily obtain an interlock with a connector, and the mounting space can be reduced as compared with the screw terminal. Can be.

 FIGS. 14 and 15 show a first modification of the present embodiment.

In this modification, a forward contactor and a reverse contactor are mounted on the same heat sink, and transmission and reception of an interlock signal and the like are performed by a photodiode and a phototransistor provided to face each other.

According to the present modification, the interlock can be obtained simply by providing the forward contactor and the reverse contactor adjacent to each other.

 FIG. 16 shows a second modification of the present embodiment.

In this modification, the reversible failure detection unit 208 is separately provided, and is detected by the logic of the logical sum output of the normal rotation input and the reverse rotation input and the load voltage. When a voltage is present, a short-circuit fault is detected.

According to the present modified side, it is economical because only one detection circuit is required.

According to this embodiment, the failure of the main switching element can be detected even in the case of the reversible type, so that there is an effect of improving the safety of the system.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the electric circuit state detection apparatus which can be used in a wide voltage range and can share a product over a different voltage range, and an electric device using the same can be obtained.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a configuration of an electric circuit state detecting device according to a first embodiment of the present invention, and FIGS. 2A and 2B show an input waveform and an output waveform of a comparator in the present embodiment, respectively. FIGS. 3 (A) and 3 (B) show the input waveform and the output waveform of the circuit condition detecting device when the circuit is normal and when the circuit is out of phase, respectively. FIG. 4 shows the present invention. FIG. 5 is a block diagram showing a configuration of an electronic contactor using the circuit state detecting device in the second embodiment for a failure detection circuit. FIG. 5 is an electric circuit diagram showing a specific configuration of a failure detection circuit unit in the present embodiment. FIGS. 5A to 5E show waveforms of portions A to E in a normal case, and FIGS. 5A to 5C show waveforms at the time of failure in FIGS.
FIG. 7 is a diagram showing waveforms of the portion E, and FIG.
FIG. 8 is a block diagram showing a main part of a modification, FIG. 8 is an electric circuit diagram showing a main part of a second modification of the embodiment, and FIG. 9 is an electric circuit showing a main part of a third modification of the embodiment. FIG. 10 is a block diagram showing a configuration of an electronic contactor with a reversible interlock provided with a failure detection circuit using a circuit state detecting device according to a third embodiment of the present invention. FIG. FIG. 12 is an electronic circuit diagram showing wiring between terminals when the present embodiment is mounted, FIG. 13 is a perspective view showing a mounting state of the present embodiment, FIG. 14, FIG. FIG. 15 is a plan sectional view and a front sectional view showing a main part of a first modification of the present embodiment, and FIG. 16 is an electric circuit diagram showing a second modification of the present embodiment. 10, 110: voltage generation means, 12, 112: voltage holding means, 16: determination means, 104, 285, 295: failure detection circuit, 125, 288, 298:
Opening / closing means, 144: control means, 145: output means, 171, Q2: comparison means

Claims (2)

(57) [Claims] 1. Voltage holding means for detecting a voltage of a three-phase circuit and generating and holding a first voltage substantially proportional to a normal voltage, and a voltage substantially equal to a current voltage of the circuit. Voltage generating means for generating a second voltage proportional to the first voltage, comparing means for comparing the first voltage with the second voltage, and determining means connected to be supplied with the output of the comparing means. Wherein the comparing means generates a signal indicating that an electric circuit is ON when a ratio of the second voltage value to the first voltage value is at a high level, and outputs the first voltage of the second voltage value to the first voltage value.
When the ratio of the second voltage value to the first voltage value is low and the ratio of the second voltage value to the first voltage value is low. It is determined that the electric circuit is normal, and the second
An electric circuit condition detecting device configured to judge that the electric circuit is abnormal when a ratio of the voltage value to the first voltage value is at a middle level. 2. Connected to a three-phase electric circuit and turned on by a control signal
An electrical device comprising: a switching unit controlled to be in one of a state and an OFF state; and a failure detection circuit provided on a secondary side of the switching unit and detecting a failure of the switching unit. A failure detecting circuit for detecting a voltage of the electric circuit and generating and holding a first voltage substantially proportional to the normal voltage; and a voltage holding means for substantially generating a first voltage substantially proportional to a current voltage of the electric circuit. Voltage generating means for generating a second voltage, comparing means for comparing the first voltage with the second voltage, and control means for controlling an output of the comparing means based on a control signal of the switching means And an output means for generating an output based on the output of the control means, wherein the comparing means sets the electric circuit in an ON state when a ratio of the second voltage value to the first voltage value is at a high level. To generate a signal and the second When the ratio of the pressure value to the first voltage value is at a low level, the control circuit is configured to generate a signal that the electric circuit is off, and the control means is provided with a control signal for turning off the open / close means to the control means. Is configured to transmit the output of the comparing means to the output means when
An electric device, wherein the output means generates an output to detect an abnormality of the opening / closing means.