JPH02148638A - Relay driving device - Google Patents

Abstract

PURPOSE:To enable the precise opening and closing of a relay contact at 0 volt in the case of a significant change of temperature between the opening or closing motions of the relay by detecting this temperature difference and newly determining a driving phase based on the obtained temperature difference. CONSTITUTION:A temperature detecting means 12 detecting the temperature near a relay, a memory means 16 temporarily storing this output, and a temperature difference calculating means 17 determining the temperature difference from the previous switching time prior to the switching of the relay are provided. Further, a driving phase determining means 18 is provided, which means inputs the temperature difference obtained by the temperature difference calculating means 17, the synchronization signal from a power source synchronization signal generating means 9, and the switching signal from a switching phase detecting means 10, respectively, and determines the driving phase of a relay contact 16 based on the measurement signal from a time difference measuring means 11 measuring the time difference of these signals. Hence, when the temperature is significantly changed between two ON motions (or OFF motions) of the relay, the relay contact can precisely be closed (or opened) at 0 volt.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a relay driving device that drives a relay at around zero volts of an AC power source.

Conventional technology In this type of conventional relay drive device, the time difference between the phase in which the relay contacts open and close and the zero phase of the AC power supply is measured, and the relay contacts are opened and closed at around zero volts of the AC power supply based on this time difference measurement value. Some relays prevent deterioration of the contacts by suppressing arc discharge that occurs between them.

Problems to be Solved by the Invention However, the relay drive device with such a configuration determines the drive phase based on the previous operating time or return time of the relay contact, but as shown in FIG. The operating time and recovery time change as the temperature changes, so if the temperature changes significantly between the two opening and closing operations, the operating time and recovery time will also change significantly, and as a result,
There was a problem that it could not be opened and closed correctly at zero volts.

In other words, in the relay drive circuit shown in Fig. 9, as the temperature rises, the resistance of the relay coil ^1a increases.
During ON operation, the current flowing through the relay coil 1a decreases, the force that attracts the relay contact 1b becomes weaker, and the operation time becomes longer. On the other hand, during the OFF operation, the current flowing through the diode 2 (flywheel diode) to the relay coil 11L becomes smaller, so the force that prevents the relay contact 1b from returning is reduced and the return time is shortened.

FIG. 10 is a characteristic diagram showing the temperature transition near the relay in a rice cooker that controls the heater by turning on the relay for an arbitrary period of 16 seconds (duty control). After the start of rice cooking, the temperature gradually rises. It is saturated at about 80°C (section marked ■). After finishing the rice cooking operation and moving to the warming operation, the temperature stabilizes at about 40'C (■ section).

When starting the second rice cooking operation mark, if the relay drive phase at point B is determined based on the operation time and return time at point A, the temperature difference between Mu B is as much as 4a℃. , the operating time becomes 0.8 (!as) shorter and the return time becomes 0.8 (m;) longer, making it impossible to drive correctly at zero volts. In addition, the deviation of the driving point becomes even larger before and after the state where neither the rice cooking operation nor the warming operation is performed (section ■).

The present invention solves these problems by correctly closing (or opening) a relay contact at zero volts even if the temperature changes significantly between two relay ON operations (or OFF operations). The purpose of this invention is to provide a relay and drive device that can.

Means for Solving the Problems In order to achieve the above object, the present invention provides temperature detection means for detecting the temperature near the relay, storage means for temporarily storing the output of the temperature detection means, and a method for opening and closing the relay. Temperature difference calculation means that calculates the temperature difference from the previous relay opening/closing time, the temperature difference obtained by this temperature difference calculation means, the power synchronization signal from the power supply synchronization signal generation means, and the opening/closing signal from the opening/closing phase detection means. and drive phase determining means for determining the drive phase of the relay contact based on the measurement signal from the time difference measuring means for inputting the respective signals and measuring the time difference.

Operation The relay drive device of the present invention has the above-described configuration, so that even if the temperature changes significantly between two relay opening operations (or closing operations), this temperature difference can be detected and the resulting advantage can be obtained. Since the drive phase is determined again based on the temperature difference, the relay contacts can be opened and closed correctly at zero volts.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. FIG. 1 is a block circuit diagram showing the main parts of a relay drive device according to an embodiment of the present invention, where 1a is a relay coil, 1b is a relay contact, 2 is a surge absorption diode, and 3 is a relay. A transistor 5 is connected through a resistor 4 as a driving means. 6 is a DC power supply, 7 is an AC power supply, and 8 is a load. Reference numeral 9 denotes power supply synchronization signal generation means for generating a signal synchronized with zero volts of the AC power supply 7;
Reference numeral 11 indicates an opening/closing phase detection means for detecting the opening/closing phase of the relay contact 1b, and 11 inputs the power synchronization signal a from the power synchronization signal generating means 9 and the opening/closing signal e from the opening/closing phase detection means 1°, and calculates the time difference between them. The time difference measuring means 12 is temperature detecting means, and is composed of a thermistor 13 provided near the relay coil 1b and a Mu/D converter 15 which receives the divided potential of the resistor 14 as input. 16 is a storage means for temporarily storing the output of the temperature detection means 12; 17 is the temperature data 16& of the storage means 16 and the output 1 of the temperature detection means 12;
21L, a temperature difference calculating means for calculating the temperature difference from the output of the time difference measuring means 11, 18 is a drive phase determining means, and
The drive phase of the relay contact 1b is determined based on the output of the temperature calculation means 17.

The power synchronization signal generating means 9 includes a diode bridge 1
The opening/closing phase detecting means 10 is composed of a diode bridge 23, resistors 24, 25, and a photocoupler 26.

In addition, 3 and 11 and 16 to 18 are CPU, RO
It is realized by a one-chip microcomputer equipped with M, RAM, input/output board, etc.

Next, the operation of this embodiment configured as described above will be explained. Figure 2 shows a 70-chart when closing the relay contact 1b.First, in step 1, the temperature difference from the previous on operation is checked, and if the temperature difference is within 10'C. If so, the process advances to step 2 and waits for the fall of the power synchronization signal to be input. When the falling edge of the power synchronization signal is input, measurement of time (phase) to is started (step 1), and the time t is measured in steps 3 and 4.

outputs a relay drive signal with a phase that matches the time ton stored in the RAM (step 6). Relay contact 1
When b is closed, the falling edge of the opening/closing signal is input in step e, and the measurement of time to is stopped. This time t
o and 1 at twice the period of the power synchronization signal, and only if they are not equal, calculate the difference between the time to and the period T1 to the time ton.
, and stores the value in the RAM as a new time ton (step 9). In other words, as shown in FIG. When output, when the AC power supply voltage CQ-(1 [+) applied to the load 8 is near zero volts, the relay contact 1b is closed, and the time t□yl+'h until the fall of the open/close signal eo is equal to the power synchronization signal I
It is twice the period of Lo, so it is equal to 1.

The time t2 is the operating time of the relay and varies depending on each relay.

On the other hand, if the relay contact 1b is closed when the AC power supply is not near zero volts because the time ton is short, the power synchronization signal 2LO, the relay drive signal b1, the AC power supply voltage C1-dl applied to the load 8, and the opening/closing The relationship of the signal e1 is as shown in FIG. 4, and the difference t4 between the time t5 and the period T1 is
is added to the time ton and stored in the RAM, returning to the state shown in FIG.

However, in step 1 of chart 70 in FIG. 2, if there is a temperature rise of 10° C. or more compared to the previous turn-on, the process proceeds to step 1o. In step 10, based on the temperature characteristics of the operating time shown in Figure 8, the operating time is 0 per 10°C rise.
．． Since it is known that the length will increase by 2m560, in order to offset the increase, ton
By decreasing the value by 0.2 m5eC and proceeding to step 2, the state shown in Fig. 3 can be maintained. vice versa,
If a decrease in temperature is found in step 1, increase ton in advance in step 11 and proceed to step 2.
Maintain the state shown in Figure 3.

Next, the operation when opening the relay contact 1b will be explained. As shown in the 70-chart in Fig. 5 and the timing diagram in Fig. 6, in steps 21 to 23, as in the case of the on operation, compensation for the shortening of the return time as the temperature rises is made in advance to toff. When the rising edge of the power synchronization signal is input in step 24, time t is reached.

The measurement is started in step 24), and the output of the relay drive signal is stopped when the time to coincides with the time toff stored in the RAM (step 26). Next, when the rising edge of the opening/closing signal is input, measurement at time t1 is started (step 28). When the falling edge of the opening/closing signal is input (point ■ in Figure e), the measurement at time t1 is stopped and the process returns to step 27, and the falling edge of the opening/closing signal is not input, and time t1 becomes time T2. (Figure 6, the opening/closing signal near zero volts of the AC power supply is High.
h) (point ■ in Figure 6), the time to,
The measurement at time t1 is stopped and the process proceeds to step 33. In step 33, the difference between the time to and the time t1 (to-1+
) and the period T1 which is twice the power synchronization signal, and only if they are not equal, the difference between the period T1 and the value (to-11) is added to the time tofT and stored in the RAM.

Figure 6 shows the relationship between the power synchronization signal &1, the relay drive signal b2, the AC power supply voltage 02''2 applied to the load 8, and the open/close signal e2 when the relay contact is open near zero volts of the AC power supply. Fig. 7 shows the power synchronization signal &1 when the relay contact is opened at a phase other than zero volts of the AC power supply, the relay drive signal b3, the AC power supply voltage as as applied to the load 8, and the opening/closing signal e5. shows the relationship between

In the case of FIG. 7, time t7 is added to time toff and stored in the RAM, and the state returns to FIG. 6 next time. The time t5 in FIGS. 6 and 7 is the return time of the relay, and the value differs depending on each relay.

As described above, the relay drive device of this embodiment repeats the operations shown in the flowcharts of FIGS. 2 and 5, so that even if the operating time and return time of the relay contact 1b increase or decrease due to temperature changes, The relay drive phase (time ton and time tof'f) is determined so that the relay contact 1b opens and closes near zero volts of the AC power supply. Therefore, relay contact 1
The voltage between the contacts when opening and closing b becomes almost zero, and the occurrence of arc discharge can be significantly reduced.

In this embodiment, the temperature correction is performed in steps of 10° C., but the invention is not limited to this, and the same effect can be achieved even if the correction is performed in other temperature ranges.

Effects of the Invention As is clear from the above explanation, the relay drive device of the present invention can significantly improve the reliability when opening and closing relay contacts near zero volts of the AC power supply, and as a result, the load Since arc discharge that occurs between contacts when switching current is suppressed is suppressed, the lifespan of the contacts is significantly improved, and variations in the lifespan can be reduced.In addition, reliability is improved and power duty control using relays is possible. This is the result.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the main parts of a relay driving device in an embodiment of the present invention in blocks, FIG. 2 is a flowchart of the same relay driving device when the relay is turned on, and FIGS. 3 and 4 are Figure 6 is a flowchart of the signal when the relay is turned on; Figure 6 is a flowchart when the relay is turned off; Figures 6 and 7 are timing diagrams of the signal when the relay is turned off. The figure shows the temperature characteristics when the relay opens and closes.
FIG. 9 is a conventional relay drive circuit diagram, and FIG. 10 is a characteristic diagram showing an example of a temperature change of the relay during rice cooking. 3...Relay drive means, 9...Power synchronization signal generation means, 10...Opening/closing phase detection means,
11... Time difference measuring means, 12... Temperature detecting means, 161.・0. . Storage means, 17...Temperature difference calculation means, 18. Drive phase determining means. Name of agent: Patent attorney Shigetaka Awano and 1 other person 2nd
0 Figure 111111 m-'' Figure Figure Figure Figure (--τ+) = t Figure

Claims (1)

[Claims] power synchronization signal generation means for generating a signal synchronized with zero volts of the AC power source; opening/closing phase detection means for detecting the open/close phase of a relay contact; and the power synchronization signal from the power synchronization signal generation means and the opening/closing phase detection means. a time difference measuring means for inputting open/close signals from the relay and measuring the time difference; a temperature detecting means for detecting the temperature near the relay; a memory means for temporarily storing the output of the temperature detecting means; a temperature difference calculation means for calculating the temperature difference from the previous time of opening and closing of the relay; and a drive phase of the relay contact based on the temperature difference obtained by the temperature difference calculation means and a measurement signal from the time difference measurement means. What is claimed is: 1. A relay drive device comprising a drive phase determining means for determining a drive phase, and a relay drive means for opening and closing the relay contacts at around zero volts of an AC power source based on an output signal from the drive phase determining means.