JPH0896682A - Relay drive - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a relay drive device capable of reducing variations in the life of relay contacts and improving reliability. In the random number generating means 13, the AC / DC converting means 9 converts the AC voltage of the AC power source 1 into a DC voltage, and the numerical converting means 10 converts the DC voltage into a predetermined numerical value, thereby changing the AC voltage. Generate a corresponding random number. The zero volt pulse generating means 6 detects the vicinity of zero volt of the AC power supply 1 and generates a zero volt pulse, and the relay drive signal generating means 11 generates a relay drive signal at a timing shifted from the timing of the zero volt pulse by the random number. Relay drive means 5
Give to. The relay contact 3 is closed or opened at the varied timing. Since this timing is not biased in synchronization with a specific phase of the AC voltage, variations in relay contact life between devices are reduced, and reliability is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay drive device for controlling energization of a relay.

[0002]

2. Description of the Related Art In recent years, relays have been widely used in automatic control, but improving the reliability of their contacts is a problem.

A conventional relay drive device will be described below with reference to the drawings. FIG. 5 is a circuit diagram showing a configuration of a conventional relay drive device. In the figure, 1 is an AC power supply, 2 is a load such as a heater, 3 is an AC power supply 1 to a load 2
Relay contacts for opening and closing the energization to the relay contacts, 4 a relay coil for controlling the opening and closing of the relay contacts 3, 5 a relay drive means for controlling the energization of the relay coil 4, and a relay driving means 6 for generating a zero volt pulse. A means for detecting the vicinity of the zero voltage of the AC power supply 1 to generate and output a zero volt pulse. Reference numeral 7 is composed of a key 7a and a resistor 7b, and a start means for the operator to input an operation start instruction. 8 is a relay for inputting the output of the start means 7 and the zero volt pulse output by the zero volt pulse generating means 6. The control means outputs a relay drive signal to the drive means 5.

The mutual relationship and operation of the above-mentioned components will be described. When the user presses the key 7a, the output of the start means 7 becomes high level (hereinafter referred to as H), the H is input to the control means 8, and the control means 8 causes the relay drive means 5 to operate.
The relay drive signal is output to. The relay driving means 5 drives the relay coil 4, the relay contact 3 is closed, and the heater 2 is energized. The control unit 8 executes the input process and the output process in synchronization with the zero volt pulse to operate the relay in the vicinity of the zero volt of the AC voltage,
The current load on the relay contacts is reduced.

[0005]

In such a conventional relay driving means, since the output timing to the relay coil 4 is always the same when viewed from the timing of the zero volt pulse, the opening / closing timing of the relay contact is specified by the AC power supply. When the phase is fixed to, and the phase is close to 90 degrees or 270 degrees, the contact is always opened and closed in the vicinity of the maximum value of the current and there is a problem that the contact life is shortened. Further, since this timing is different for each device as a unique value of each device, there is a problem that the contact life varies among the devices.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a relay drive device capable of reducing the variation in the life of relay contacts and increasing the reliability of the relay contacts.

[0007]

In order to achieve the above object, the present invention provides a relay contact for opening and closing the energization of a load connected to an AC power source, a relay coil for controlling the opening and closing of the relay contact, and Relay drive means for controlling energization of the relay coil, zero volt pulse generating means for detecting near zero voltage of the AC power source and generating zero volt pulse, random number generating means for generating a random number, and the random number generating means And a relay drive signal generating means for outputting a relay drive signal to the relay drive means at the timing of adding the time value to the timing of the zero volt pulse generated by the zero volt pulse generating means, It is a relay drive device provided with.

[0008]

According to the present invention, in the above structure, the zero volt pulse generating means generates a zero volt pulse in the vicinity of zero volt of alternating current, and the random number generating means generates a random number on the basis of fluctuations in AC voltage or temperature change. The relay drive unit drives the relay coil at a timing shifted by the random number from the timing of the zero volt pulse, and the relay contact opens and closes at a random timing.

[0009]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the relay drive device of the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing the configuration of this embodiment. The same components as those of the conventional example shown in FIG. 5 are assigned the same reference numerals and detailed explanations thereof will be omitted. The present invention is different from the conventional example in that it is provided with an AC / DC converter 9 composed of a diode 9a, resistors 9b and 9c, and a capacitor 9d, a numerical converter 10 for generating a random number, and a relay drive signal generator 11. The timing of closing the relay contact 3 is randomly changed. The AC / DC converter 9 and the numerical converter 10 constitute a random number generator 13.

The operation of the above configuration will be described. FIG. 2 is a waveform diagram showing the operation of this embodiment. The waveform is based on the potential at point a shown in FIG. 1, and the waveform (b) is shown in FIG.
1 shows the voltage waveform at point a, that is, the AC voltage waveform, waveform (c) shows the waveform at point c in FIG. 1, that is, the waveform of the zero volt pulse that is the output of the zero volt pulse generating means 6, and waveform (d) in FIG. Point d, that is, the relay drive signal that is the output of the relay drive signal generation means 11 is shown. When the user presses the key 7a, the output of the start means 7 becomes H. The zero volt pulse generating means 6 is shown in FIG.
The vicinity of the zero voltage of the voltage waveform of the AC power supply 1 shown in (b) is detected and the zero volt pulse shown in FIG. 2 (c) is output. On the other hand, the AC / DC converter 9 receives the voltage of the AC power supply 1, rectifies it by the diode 9a, and smoothes the voltage divided by the resistors 9b and 9c by the capacitor 9d, thereby converting the AC voltage of the AC power supply 1 into the DC voltage. The voltage is converted and output to the numerical conversion means 10. This output voltage is AC power supply 1
Fluctuates depending on the voltage of. For example, if the DC output voltage is set to 4V when AC 100V is input,
The output voltage changes by 40 mV with a change of 1 V AC.

The numerical value conversion means 10 inputs such a DC voltage and outputs a numerical value from 0 to 9. In this embodiment, it is assumed that only one digit of the output voltage of the AC / DC converting means 9 in mV unit is output. Relay drive signal generating means 11
Is a timing when the output value of the numerical conversion means 10 at that time is read when the output of the start means 7 becomes H and the output value is delayed from the rising of the zero volt pulse of the zero volt pulse generation means 6 by 2 ms. Then, a drive signal is output to the relay drive means 5. For example, if the value of the AC power supply 1 is 100 V, the output voltage of the AC / DC converter 9 is 4 V, that is, 4000 mV, and the output value of the numerical converter 10 is 0. Therefore, the relay drive signal generator 11 to the relay driver 5 is connected. 2D, the output timing of the drive signal coincides with the rising timing of the zero volt pulse. Since the voltage of the AC power supply supplied to a general household is constantly fluctuating and the output voltage of the AC / DC converting means 9 changes according to the fluctuation value, the output value of the numerical converting means 10 is from 0 to 9. And the output timing of the drive signal from the relay drive signal generation means 11 to the relay drive means 5 is
As shown in FIG. 2 (d-1) and FIG. 2 (d-9),
It will vary from 0 ms to 18 ms from the rise of the zero volt pulse.

When a drive signal is output to the relay drive means 5, a base current flows through the transistor 5a through the resistor 5b, the transistor 5a becomes conductive, the relay coil 4 is energized, and the relay contact 3 is closed. By the above operation, the output timing to the relay driving means 5 varies every time, so the closing phase of the relay contact 3 also varies, and the relay contact 3 can be closed at a timing that is not biased to a specific phase of the AC power supply. The same operation can be performed when the relay contact 3 is opened.

As described above, according to the relay drive apparatus of the present embodiment, the AC / DC converting means for converting the voltage of the AC power source into the DC and the output voltage of the AC / DC converting means are measured, and the measured value is set to a predetermined value. A relay contact is provided by changing the timing of turning on or off the relay contact depending on the AC phase by converting the voltage of the AC power supply when the relay turns on or off by its output. It is possible to suppress variations in life and improve reliability.

(Second Embodiment) A second embodiment of the relay drive device of the present invention will be described below with reference to the drawings. FIG. 3 is a circuit diagram showing the configuration of this embodiment. In addition,
The same components as those of the conventional example shown in FIG. 5 are assigned the same reference numerals and detailed explanations thereof will be omitted. The present embodiment is different from the conventional example in that it includes a numerical conversion means 10, a relay drive signal generation means 11, and a temperature detection means 12 composed of a resistor 12a and a temperature detection element 12b, and opens and closes the relay contacts. The purpose is to vary the timing. The temperature detection means 12 and the numerical conversion means 10 constitute a random number generation means 13.

The operation of the above configuration will be described. FIG. 4 is a waveform diagram showing the operation of this embodiment. Note that each waveform shows the voltage waveform of the signal at each point shown in FIG. 3, as in the first embodiment. When the user presses the key 7a, the output of the start means 7 becomes H. The zero volt pulse generating means 6 detects the vicinity of the zero voltage of the AC power source 1 and then, as shown in FIG.
As shown in, a zero volt pulse is output. on the other hand,
The temperature detecting means 12 supplies a current to the diode 12b, which is a temperature detecting element, via the resistor 12a,
The forward voltage of b is output to the numerical conversion means 10. This output voltage varies depending on the temperature of the diode 12b. If the temperature characteristic of the forward potential of the diode 12b is 2 mv / ° K, the output voltage changes by 2 mv with a temperature change of 1 ° k. Further, the numerical conversion means 10 outputs numerical values 0 to 9 according to the input voltage. In this embodiment, only one digit of the output voltage of the temperature detecting means 12 is output in units of 0.1 mV. For example, the forward voltage of the diode 12b is 62
If it is 0.5 mV, the numerical value 5 is output. When the output of the start means 7 becomes H, the relay drive signal generation means 11 reads the output value of the numerical conversion means 10 at that time,
The drive signal is output to the relay drive means 5 at a timing delayed by a value obtained by multiplying the output value of the zero volt pulse of the zero volt pulse generation means 6 by 2 ms.

For example, the output value of the temperature detecting means 12 is 6
If it is 20.0 mv, the output value of the numerical conversion means 10 becomes 0, so the output timing of the drive signal from the relay drive signal generation means 11 to the relay drive means 5 is shown in FIG. 2 (d-0).
As shown in, it coincides with the rising timing of the zero volt pulse. In general, the ambient temperature of the diode 12b constantly fluctuates depending on the room temperature and the operating state of the equipment used, and the output voltage of the temperature detecting means 12 changes according to the fluctuation value. Therefore, the output value of the numerical conversion means 10 is 0. To 9 to output the relay drive signal generation means 11
The output timing of the drive signal from the relay drive means 5 varies from 0 ms to 18 ms from the rise of the zero volt pulse. 2 (d-1) shows an example of 2 ms, and FIG. 2 (d-9) shows an example of 18 ms. Relay drive means 5
When the drive signal is output to the transistor 5, the base current of the transistor 5a flows through the resistor 5b, the transistor 5a becomes conductive, the relay coil 4 is energized, and the relay contact 3 is closed. By the above operation, since the output timing to the relay driving means 5 varies every time, the closing phase of the relay contact 3 also varies, and the relay contact 3 can be closed at a timing not biased to a specific phase of the AC power supply 1. Even when the relay contact 3 is opened, the relay contact 3 can be opened without biasing to a specific phase of the AC power supply 1 by outputting an OFF signal in the same operation as described above.

As described above, according to the present embodiment, the temperature change detected by the temperature detecting means 12 is converted into a numerical value by the numerical converting means 10, and the timing for turning the relay on or off is determined by the numerical value with respect to the AC phase. By making them dispersed, it is possible to suppress the variation in the life of the relay contacts and improve the reliability.

Needless to say, a temperature sensor such as a thermistor may be used as the temperature detecting means.

[0019]

As is apparent from the above description, according to the present invention, a relay contact for opening and closing the energization of a load connected to an AC power source, a relay coil for controlling the opening and closing of the relay contact, and a relay coil The relay drive means for controlling energization, the zero volt pulse generation means for detecting a zero voltage near the zero voltage of the AC power source and generating a zero volt pulse, the random number generation means for generating a random number, and the random number generation means are generated. A relay drive signal generating means for converting a random number into a time value and outputting a relay drive signal to the relay driving means at a timing obtained by adding the time value to the timing of the zero volt pulse generated by the zero volt pulse generating means. This allows the relay contacts to open and close at random timing, allowing the timing not to be biased to a specific phase of the AC voltage. By being opened and closed by grayed, with variations in the contact life is reduced, reliability is improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment of a relay drive device of the present invention.

FIG. 2 is a waveform chart showing the operation of the embodiment.

FIG. 3 is a circuit diagram showing a configuration of a second embodiment of a relay drive device of the present invention.

FIG. 4 is a waveform chart showing the operation of the embodiment.

FIG. 5 is a circuit diagram showing a configuration of a conventional relay drive device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Load 3 Relay contact 4 Relay coil 5 Relay drive means 6 Zero volt pulse generation means 9 AC / DC conversion means (random number generation means) 10 Numerical value conversion means (random number generation means) 11 Relay drive signal generation means

Claims (3)

[Claims] 1. A relay contact for opening and closing the energization of a load connected to an AC power source, a relay coil for controlling the opening and closing of the relay contact, a relay driving means for controlling the energization of the relay coil, and a zero of the AC power source. Zero-volt pulse generating means for detecting near-voltage and generating zero-volt pulse, random-number generating means for generating random numbers, and converting the random number generated by the random-number generating means into a time value to generate the zero-volt pulse. A relay drive signal generating means for outputting a relay drive signal to the relay drive means at a timing obtained by adding the time value to the timing of the zero volt pulse generated by the means. 2. An AC / DC converting means for converting the voltage of an AC power supply into a DC voltage, and measuring an output voltage of the AC / DC converting means,
The relay drive device according to claim 1, further comprising: a random number generating unit configured to convert the measured value into a predetermined numerical value and outputting the predetermined numerical value generated by the numerical converting unit as a random number. 3. A random number comprising a temperature detecting means and a numerical value converting means for converting the temperature measured by the temperature detecting means into a predetermined numerical value, wherein the predetermined numerical value generated by the numerical value converting means is outputted as a random number. The relay driving means according to claim 1, further comprising a number generating means.