JP2779106B2 - Open / close control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open / close control device for controlling on / off of a contact switch and a non-contact switch inserted in series in a load circuit in accordance with a current supply state to a load.

[0002]

2. Description of the Related Art In recent years, a solid state contactor (hereinafter, referred to as SSC) using a thyristor has been used as a switch of a load circuit for supplying power to a load such as an induction motor. This SSC withstands an increase in the opening and closing frequency, does not cause chattering phenomenon,
There is an advantage that noise can be reduced.

However, since the SSC is easily broken by an overcurrent due to its structure, it needs to be turned off before the overcurrent flows to protect itself. If a short-circuit fault occurs, it is dangerous to supply power to the load even if an off control signal is applied to this SSC, so it is dangerous to connect an electromagnetic contactor in series with the SSC. It was also necessary to turn off the contactor to protect loads such as the motor.

A device having such a protection function is disclosed in, for example, JP-A-63-209429.
In this device, the above-mentioned electromagnetic contactor and SSC are inserted in series into a load circuit to which a three-phase AC motor is connected, and based on an output signal of a current transformer (hereinafter referred to as CT) for detecting a phase current of the motor. Various logical judgments are made, and the SSC and the electromagnetic contactor are turned on and off according to the judgment result.

[0005]

Generally, when controlling a motor for driving a pump or the like, an overload protection function for turning off a load circuit when a current of a predetermined value or more flows through the motor, and one of the motors An open-phase protection function that also turns off the load circuit for an open phase in which the phase voltage disappears is often provided.

The above-described conventional device does not have an overload protection function or an open-phase protection function. Therefore, another control system must be provided for the SSC and the electromagnetic switch for overload protection and open-phase protection, which complicates the configuration of the switching control device and increases the cost. was there.

The present invention has been made to solve the above problems, and has as its object to provide an opening / closing control device capable of simplifying the configuration and reducing the cost of the device.

[0008]

According to the present invention, a contact switch and a contactless switch which are inserted in series in a load circuit are provided.
In a switching control device that performs on / off control according to a current supply state to a load, a rectification unit that obtains a full-wave rectified signal of each phase current supplied to the load, and a load based on the full-wave rectified signal of the rectification unit. The detecting means for detecting the current supply to the load, the overload state of the load and the open-phase state of the load, and the contact switching means and the non-contact switching means are turned on in accordance with a start command applied via external operation means, and stopped. A control signal for turning off according to the command is output, and between the output of the control signal for turning on and the output of the control signal for turning off, the energization signal is not output from the detecting means. Is output, and a control signal for forcibly turning off the non-contact opening / closing means is output when any one of the failures is output, and the control signal is output. Is obtained by a logical operation means for forcibly output the control signal to turn off the reed opening and closing means in failure telegraphic communication is output.

[0009]

According to the present invention, the non-contact switching means is forcibly turned off when any one of the following faults occurs: no energization signal is output, an overload signal is output, and an open phase signal is output. A control signal is output which forcibly turns off the contact opening / closing means in response to a failure that an energizing signal is output even if this control signal is output. The control system for the means and the non-contact switching means is integrated into one, and the main part of the control system can be integrated into an IC, so that the configuration is simplified and the device cost is reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram showing the overall configuration of one embodiment of the present invention. In FIG. 1, an SSC 4 as a non-contact switching device and an electromagnetic contactor 6 as a contact switching device are connected in series to a load circuit having a three-phase induction motor (hereinafter simply referred to as a motor) 2 as a load. . In this case, the electromagnetic contactor 6 is arranged on the AC power supply side as a main switch. Further, a CT 10 for detecting a phase current is provided between the SSC 4 and the electric motor 2. This CT10 is provided in each of two phases out of three phases, and each secondary side is a rectifier circuit.
Connected to 12. The rectifier circuit 12 has six diodes connected in a three-phase bridge, and outputs a pulsating current obtained by full-wave rectifying a three-phase alternating current. The rectifier circuit 12 includes an inverter 14 that detects energization of the motor 2, an overload detection circuit 16 that detects an overload state of the motor 2, and an open phase detection circuit 18 that detects an open phase state of the motor 2. It is connected.

The logical operation circuit 20 developed for controlling the SSC 4 and the electromagnetic contactor 6 has an input circuit 22 and an output circuit 24. Of these, the input circuit 22 includes the inverter 14, The output terminals of the overload detection circuit 16 and the phase loss detection circuit 18 are connected, and the output coil 24 is connected to the operation coil 8 for making the electromagnetic contactor 6 differential and the control terminal of the SSC 4. On the other hand, a start / stop switch 26 and a failure indicator lamp 28 are connected to the logical operation circuit 20.

FIG. 2 is a circuit diagram showing a detailed configuration of the rectifier circuit 12, and includes three diodes D connected in a three-phase bridge.
And ₁ to D _6, and a resistor R _1, R ₂ variable resistor VR to form a load circuit. Here, one end of one CT 10 is connected between the diodes D ₁ and D ₂ connected in series, and the other end is connected between the diodes D ₃ and D ₄ connected in series. One end of another CT 10 is connected between the diodes D ₅ and D ₆ connected in series, and the other end is connected between the diodes D ₃ and D ₄ . On the other hand, a resistor R ₁ and a series connection circuit of a variable resistor VR and a resistor R ₂ are connected in parallel to both ends of the diode series connection circuit, and one end of the resistor R ₂ , that is, the variable resistor V 2
The connection end to R is connected to the output terminal T ₁ , and the other end of the resistor R ₂ is connected to the output end T ₂ .

FIG. 3 is a circuit diagram showing a detailed configuration of the overload detection circuit 16. As shown in FIG. It is composed of a comparator COMP _1, reference power source B, the capacitor C _1, C _2, resistors R ₅ to R _7, a Zener diode ZD and a diode D _8.
Here, resistors R ₅ and R ₆ are connected in series between the input terminals T ₃ and T _4, and an interconnection point of these resistors is a comparator CO.
It is connected to the non-inverting input terminal of the MP ₁ (+). Inverting input terminal of the comparator COMP ₁ and the input terminal T ₄ (-) reference power supply B is connected between the. A resistor R ₇ and a capacitor C ₁ are connected in series between the input terminals T ₃ and T ₄ , and their mutual junction is connected to the output terminal of the comparator COMP ₁ and to the output terminal T ₅ . Have been. Further, a Zener diode ZD, a diode D ₈ and a capacitor C ₂ are connected in series between the input terminals T ₃ and T ₄ , and a junction between the diode D ₈ and the capacitor C ₂ is connected to the output terminal T _6. ing. Incidentally, an input terminal T ₄ and an output terminal T ₇ are directly connected.

FIG. 4 is a circuit diagram showing a detailed configuration of the phase loss detecting circuit 18. As shown in FIG. This circuit is a capacitor C ₄ -C _6, resistors R ₁₁ to R ₁₄ and Taiodo D _11, D _12. Here, a capacitor C ₄ and the diode D ₁₁ between the input terminals T _11, T ₁₂ are connected in series. The resistance R
₁₁ and the capacitor C ₅ is connected in parallel, the parallel connection circuit, via the diode D _12, is connected in parallel to the diode D _11. One end of the parallel connection circuit of a resistor R ₁₁ and capacitor C ₅ is connected to the output terminal T _13, the other end, via a parallel connection circuit of a resistor R ₁₄ and capacitor C _6, connected to an output terminal T ₁₄ Have been. Also, the input terminal T
Resistors R12 and R13 are connected in series between ₁₁ and the output terminal T14.

The output terminals T ₁₃ and T _{14 of the} open phase detection circuit 18
Are connected to input terminals T ₁₆ and T ₁₇ of the input circuit 22, respectively. Then, in the input circuit 22 has a non-inverting input terminal of the comparator COMP ₂ is connected to the input terminal T _16, T
One end of a series connection circuit of resistors R ₁₅ and R ₁₆ is connected to _17, and the inverting input terminal of the comparator COMP ₂ is connected to the junction of these resistors. In addition, the comparator COMP ₂
The timer T is connected to the output terminal of the timer T.

The operation of the embodiment constructed as described above will be described below. When the start command is generated by operating the start / stop switch 26, the logical operation circuit 20 outputs the output circuit.
The operation coil 8 is excited via 24 to turn on the electromagnetic contactor 6, and an ON signal is applied to the control terminal of the SSC 4 to turn the SSC 4 on. When the start / stop switch 26 is operated to generate a stop command, the logical operation circuit 20 stops the excitation of the operation coil 8 and turns off the electromagnetic contactor 6.
Is turned off, the output of the ON signal to the SSC4 is stopped, and the SSC4 is turned off.

When both the SSC 4 and the electromagnetic contactor 6 are in the ON state, power is supplied to the electric motor 2 to perform a predetermined work.
In this case, an AC voltage generated on the secondary side of the CT 10 is applied to the rectifier circuit 12. The rectifier circuit 12 performs full-wave rectification of this voltage to generate a pulsating voltage shown in FIG. 5A between the output terminals T ₁ and T ₂ . The magnitude of the pulsating voltage can be made appropriate by adjusting the variable resistor VR.
That is, even if the rating of the electric motor 2 changes, it can be constantly adjusted to a value suitable for control.

Then, the inverter 14 detects the rectified voltage and supplies an energization signal to the logical operation circuit 20.

The overload detection circuit 16 also receives the rectified voltage of the rectifier circuit 12 between the input terminals T ₃ and T ₄ , and outputs the rectified voltage to the output terminal T ₇ until the magnitude reaches 1.25 times the rated current. T ₅ and the level of T ₆ respectively kept "L".

Here, it is assumed that the load increases and a current of 1.25 times or more of the rated current flows through the motor 2. At this time, the voltage between the terminals T ₃ and T ₄ is divided by the resistors R ₅ and R ₆ , and when the divided voltage exceeds the voltage of the power supply B, the comparator COMP ₁
Circuit state is inverted. Then, the output voltage, i.e., the voltage of the output terminal T ₅ is resistor R ₇ and capacitor C
It increases with a time constant determined by ₁ . On the other hand, it is assumed that the load further increases and a current 10 times the rated current flows through the motor 2. Zener diode ZD has a Zener voltage equal to the voltage between terminals T ₃ and T ₄ corresponding to this state. Therefore, the voltage across the capacitor C ₂ in the case is soaring, the voltage of the output terminal T ₆ also increases rapidly.

[0021] The present embodiment, the voltage of the output terminal T ₅ exceeds a predetermined level, and, at the stage where the logical OR condition of the voltage of the output terminal T ₆ exceeds a predetermined level is satisfied,
The protection operation is performed by turning off the SSC4. In this case, the relationship between the operating time and the overcurrent magnification with respect to the rated current follows the anti-time drooping characteristic as shown in FIG. The inverse time drooping characteristic, the resistor R ₇ and inverse time characteristic which is determined by the capacitor C _1, is obtained by combination of the drooping characteristic determined by the Zener voltage of the Zener diode. And, the overcurrent ratio to the rated current is about 1.25 to 10
It can be seen that the protection operation is performed in a shorter time as the overcurrent magnification increases, and the protection operation is performed instantaneously when the overcurrent magnification exceeds 10.

On the other hand, the phase loss detecting circuit 18 receives the rectified voltage of the rectifier circuit 12 between the terminals T ₁₁ and T ₁₂ and detects a failure in which one of the three phase voltages applied to the motor 2 is missing. is there. In this case, if I is a three-phase AC voltage normal to the electric motor 2 is supplied, the rectifier circuit 12, as shown in FIG. 5 (a), and outputs a small ripple voltage ripple component V _AC. Wakashi, when one phase is absent, the rectifier circuit 12 and a single-phase full-wave rectification operation, as shown in FIG. 5 (b), and outputs a large single-phase full-wave rectified voltage ripple V _AC. The phase loss detecting circuit 18 detects the phase loss by comparing the ripple with a threshold value. That is, taken out AC divided by the capacitor C _4, rectifies half-wave one by this AC component by the diode D _11, D _12, subsequently, is smoothed by a resistor R ₁₁ and capacitor C _5, a DC voltage appears at the output terminal. Also, input terminals T ₁₁ , T ₁₂
The voltage between them is divided by the resistors R ₁₂ , R ₁₃ and R ₁₄ , and the capacitor C ₆ is charged to the illustrated polarity by the voltage across the resistor R ₁₄ to generate a constant DC voltage at the output terminal T ₁₇ .

[0023] Incidentally, in the input circuit 22, the comparator C a DC voltage corresponding to ripple at the output terminal T ₁₃
In addition to the non-inverting input terminal of the OMP ₂ , the voltage generated at the output terminal T ₁₄ is divided by the resistors R ₁₅ and R ₁₆ to generate a comparator COMP ₂
Of the inverting input terminal.

The large voltage appearing at the output terminal T ₁₃ is the open phase state, whereby the circuit state of the comparator COMP ₁ is inverted, the timer T starts its operation by the output, open-phase signal after the time-up logic operation Applied to circuit 20.

As described above, the energization signal of the inverter 14, the overload signal of the overload detection circuit 16, and the open-phase detection circuit 18
Are respectively applied to the logical operation circuit 20. The logic operation circuit 20 controls these signals and the start / stop switch 26
A logical operation is executed on the basis of the above-mentioned command to control ON / OFF of the SSC 4 and the electromagnetic contactor 6 and display control of the failure display lamp 28.

FIGS. 7, 8 and 9 show this logical operation circuit 20.
6 is a flowchart showing the processing procedure of FIG. Hereinafter, the operation will be described with reference to this flowchart.

First, FIG. 7 shows a start-up routine 100. In step 101, a control signal for turning on the SSC 4 is output, and subsequently, in step 102, a timer is operated. In other words, after the motor 2 has entered the steady operation state, the presence or absence of an energization signal is determined in step 101, the presence or absence of an overload signal in step 104, and the presence or absence of an open phase signal in step 105. If there is no energization signal, no overload signal, and no open phase signal, it is determined in step 106 whether a stop command has been input from the start / stop switch 26. If the stop command has not been input, steps 103 to 103
Step 106 is repeated, and when the stop command is input, the process proceeds to the stop routine 200. On the other hand, when it is determined in step 103 that there is no energization signal, it is determined in step 107 that the SSC 4 is non-conductive, and in step 110, a control signal for turning off the SSC 4 is transmitted.
Move on to If it is determined in step 104 that there is an overload signal, it is determined in step 108 that the overload signal is present.
If it is determined in step 105 that there is an open phase signal, step 10
9 determines that the phase is missing, and in step 110, the SSC
Then, a control signal for turning off the control signal No. 4 is transmitted, and then the process proceeds to the failure processing routine 300.

FIG. 8 shows the stop routine 200. In this routine, in step 201, SSC4
And outputs a control signal for turning off. Then, in step 202, the timer is operated. After the timer has timed out, that is, after the motor 2 is stopped, the presence or absence of the energizing signal is determined in step 303. If the energizing signal is present, the SSC4 is determined in step 204. Is determined to be a continuity, that is, a short-circuit failure, and a control signal for turning off the electromagnetic contactor 6 is output in step 205, and the routine proceeds to a failure routine 300.

Next, FIG. 9 shows the failure routine 300. In this routine, a failure is displayed in step 301, and a signal indicating the content of the failure is output in step 302,
In step 303, these reset operations are performed to return to the initial state.

The logical operation circuit 20 executes the above-described processing, so that the SSC 4 is activated by any one of the failures of outputting the energization signal, outputting the overload signal, and outputting the open-phase signal. Even if the control signal is forcibly turned off and the control signal is output, the electromagnetic contactor 6 can be forcibly turned off due to a failure in which the energization signal is output.

In the above embodiment, the overload detection circuit 16 having a specific configuration is provided, and one of the output terminals T ₅ and T ₆ of the overload detection circuit 16 has a logic level “H”.
Is output at the time of reaching the SSC4, the power supply circuit of the electric motor 2 can be turned off in accordance with the anti-time droop characteristic of FIG.

In the present embodiment, energization, overload, and open phase are each detected by the rectified output voltage of the rectifier circuit 12, and logic judgment is performed based on these detection signals. The control system for the load and the phase loss is also unified, and an effect that a dedicated IC can be adopted as the logical operation circuit 20 is obtained.

[0033]

As is apparent from the above description, according to the present invention, the problem of the conventional device in which another control system must be provided for the SSC and the electromagnetic switch is solved, and the present invention is not limited to this. A control system for the contact opening / closing means and the non-contact opening / closing means is integrated into one, and simplification of the configuration and reduction of the apparatus cost are achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a detailed configuration of a rectifier circuit according to one embodiment of the present invention.

FIG. 3 is a circuit diagram showing a detailed configuration of an overload detection circuit according to one embodiment of the present invention.

FIG. 4 is a circuit diagram showing a detailed configuration of an open phase detection circuit according to one embodiment of the present invention.

FIG. 5 is a waveform chart for explaining the operation of one embodiment of the present invention.

FIG. 6 is a diagram showing a relationship between an operation time and an overcurrent magnification in order to explain an operation of one embodiment of the present invention.

FIG. 7 is a flowchart for explaining the operation of one embodiment of the present invention.

FIG. 8 is a flowchart for explaining the operation of one embodiment of the present invention.

FIG. 9 is a flowchart for explaining the operation of one embodiment of the present invention.

[Explanation of symbols]

 2 Three-phase induction motor 4 SSC 6 Magnetic contactor 8 Operation coil 10 CT 12 Rectifier circuit 14 Inverter 16 Overload detection circuit 18 Missing phase detection circuit 20 Logical operation circuit 22 Input circuit 24 Output circuit 26 Start / stop switch 28 Failure indicator lamp

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahisa Takayama 1-10-13 Iguchi, Mitaka City, Tokyo Kasuga Electric Co., Ltd. Second Engineering Department (72) Inventor Yoshito Shinohara 1 Iguchi, Mitaka City, Tokyo No. 10-13 Kasuga Electric Co., Ltd. In the second technical department (56) References JP-A-63-99722 (JP, A) JP-A-63-209429 (JP, A) JP-A 1-234095 (JP, A) JP-A-6-105452 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02H 7/08-7/097 H02P 7/36-7/625

Claims (1)

(57) [Claims] An open / close control device for controlling on / off of a contact switching device and a non-contact switching device inserted in series in a load circuit according to a current supply state to a load. Rectifying means for obtaining a full-wave rectified signal of current; energizing a load based on the full-wave rectified signal of the rectifying means;
Detecting means for detecting an overload state of the load and an open-phase state of the load, respectively, the contacted switching means and the non-contact switching means are turned on according to a start command applied via external operating means,
In response to the stop command, a control signal for turning off is output, and between the output of the control signal for turning on and the output of the control signal for turning off, the energizing signal is not output from the detection means. Load signal is output,
And, output of a control signal for forcibly turning off the non-contact opening / closing means in the case of any one of failures in which an open phase signal is output, and even if this control signal is output, the energization signal is output. A logic operation means for outputting a control signal for forcibly turning off the contacted switching means in response to the output failure.