JP2021044102A - Electric equipment - Google Patents

Abstract

To solve such a problem that a relay contact is deteriorated due to discharge generated when the relay contact is opened.SOLUTION: In electric equipment, a zero-cross signal Sp becomes active during a period when an AC power supply voltage Pw is a value that does not generate discharge between relay contacts 24, and a control section 17 generates such a relay control signal Sc that the relay contacts 24 are opened during an active period of a zero-cross signal Sp, using information obtained from a relay contact signal Sk when the relay contacts 24 was previously opened.SELECTED DRAWING: Figure 2

Description

The present invention relates to electrical equipment including relay contacts.

Patent Document 1 discloses a method of optimizing a relay control signal for each device during a test run in order to open and close the relay contact in the vicinity of the zero cross of the AC power supply voltage.

Japanese Unexamined Patent Publication No. 2014-216144 (published on November 17, 2014)

In the above method, for example, when the AC power supply voltage fluctuates from the time of test run, a discharge may occur between the relay contacts when the relay contacts are opened, and the relay contacts may deteriorate.

The electrical equipment according to the present invention generates a load, a relay contact, a zero-cross signal generator that generates a zero-cross signal corresponding to the zero-cross of the AC power supply voltage, and a relay contact signal indicating an electrical state between the relay contacts. An electric device including a relay contact signal generation unit and a control unit that generates a relay control signal, the zero cross signal becomes active during a period in which the AC power supply voltage is a value that does not cause discharge between the relay contacts. The control unit uses the information obtained from the relay contact signal when the relay contact was previously opened to generate a relay control signal such that the relay contact opens during the active period of the zero cross signal.

According to the above configuration, even when the AC power supply voltage fluctuates, the period in which the AC power supply voltage does not cause discharge between the relay contacts and the active period of the zero cross signal match. Therefore, when the control unit uses the information to generate a relay control signal that opens the relay contact during the active period, for example, the generation of electric discharge when the relay contact is opened is eliminated, and deterioration of the relay contact is suppressed. be able to.

In the electrical equipment according to the present invention, the control unit uses information obtained from the relay contact signal when the relay contact was previously closed to perform relay control such that the relay contact closes during the active period of the zero cross signal. It may be configured to generate a signal.

According to the above configuration, the control unit uses the information to generate a relay control signal that closes the relay contact during the active period, so that the generation of electric discharge due to the bounce when closing the relay contact is eliminated. Deterioration of relay contacts can be suppressed.

In the electric device according to the present invention, the active period may be set based on the characteristics of the load and the characteristics of the relay contact.

According to the above configuration, the period in which the AC power supply voltage is a value that does not cause discharge between the relay contacts and the active period of the zero cross signal can be matched with high accuracy, and the occurrence of discharge can be further suppressed. ..

In the electric device according to the present invention, the control unit may be configured to be set within the active period and generate a relay control signal such that the relay contact opens in a target period shorter than the active period.

According to the above configuration, even if the value of the AC power supply voltage that does not cause discharge between the relay contacts fluctuates (approaches zero) due to aging of the relay contacts or the like, the generation of discharge can be suppressed.

In the electric device according to the present invention, when the control unit determines based on the information that the timing at which the relay contact was opened last time is out of the target period, the reference timing and the relay control signal When it is determined that the timing at which the relay contact was opened last time is included in the target period while the delay time, which is the time difference from the timing at which the relay contact is activated, is changed from the previous value, the delay time is changed to the previous value. Same as the value.

According to the above configuration, even if the opening timing of the relay contact deviates from the target period, the opening timing of the relay contact can be returned (converged) to the target period by performing the series of steps once or more.

In the electric device according to the present invention, the relay contact signal maintains the same level regardless of the value of the AC power supply voltage during the period when the relay contact is closed.

According to the above configuration, the electrical state between the relay contacts can be easily and accurately detected by the relay contact signal.

According to the present invention, since the relay contacts can be repeatedly opened without causing an electric discharge, deterioration of the relay contacts can be suppressed.

It is a block diagram which shows the structure of the electric device which concerns on embodiment. It is a timing chart which shows the operation (when the relay contact is opened) of the electric device which concerns on embodiment. It is explanatory drawing about zero cross pulse (ZP2). It is a flowchart which shows the generation process (when the relay contact is opened) of the relay control signal which concerns on embodiment. It is a circuit diagram which shows the structural example of the zero cross signal generation part. It is a timing chart which shows the operation (when the relay contact is closed) of the electric device which concerns on embodiment. It is explanatory drawing which shows the zero cross pulse (ZP11). It is a flowchart which shows the generation process (when the relay contact is closed) of the relay control signal which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 8. FIG. 1 is a block diagram showing a configuration of an electric device according to an embodiment. FIG. 2 is a timing chart showing the operation of the electric device according to the embodiment (when the relay contact is opened).

As shown in FIG. 1, the electric device 30 according to the present embodiment includes a load 22, a relay contact 24, a relay contact drive unit 18, a zero cross signal generation unit 15, a relay contact signal generation unit 16, and a control unit 17. The electric device 30 is connected to the AC power supply 40, and the relay contact 24 is provided between the AC power supply 40 and the load 22.

The AC power source 40 may be a commercial power source, or may be a power source for private power generation in facilities, homes, vehicles, and the like. An example of the load 22 is a heater, but the load 22 is not limited to this. For example, it may be a motor that passes a large current. The relay contact 24 is, for example, two contacts included in a mechanical relay (including a hinge type electromagnetic relay, an electromagnetic contactor, and an electromagnetic switch), and a state in which the two contacts of the relay contact 24 are in contact is a relay contact. The state in which the relay contact 24 is closed and the state in which the two contacts of the relay contact 24 are separated from each other are defined as the state in which the relay contact 24 is open. The voltage between the relay contacts (between the two contacts) is Vs.

The zero-cross signal generation unit 15 is connected in parallel with the AC power supply 40 to generate a zero-cross signal Sp corresponding to the zero-cross of the AC power supply voltage. The relay contact signal generation unit 16 is connected in parallel with the load 22 to generate a relay contact signal Sk indicating an electrical state between the relay contacts.

The control unit 17 is, for example, a microcomputer including a processor and a memory, generates a relay control signal Sc using the zero cross signal Sp and the relay contact signal Sk, and outputs the relay control signal Sc to the relay contact drive unit 18. The relay control signal Sc is a signal for controlling the relay device 27 including the relay contact 24 and the relay contact driving unit 18. The relay contact drive unit 18 drives (closes and opens) the relay contact 24 in response to the relay control signal Sc.

The electric device 30 is, for example, a toaster, a humidifier, an electric kettle, a kettle, and the like, but is not limited thereto. It may be a drive device including a motor.

Hereinafter, a case where the relay contact 24 is opened will be described.

As shown in FIG. 2, the AC power supply 40 is, for example, an AC power supply having a voltage of 100 V and a frequency of 60 Hz, and the period Th of the AC power supply voltage Pw is 16.6 [ms]. The zero-cross signal Sp in FIG. 2 has a zero-cross pulse ZP1 corresponding to the −180 ° phase of the AC power supply voltage Pw, a zero-cross pulse ZP2 corresponding to the 0 ° phase of the AC power supply voltage Pw, and a + 180 ° phase of the AC power supply voltage Pw. Includes the corresponding zero cross pulse ZP3.

The zero-cross pulse ZP1 falls at time t0 (reference timing), becomes active (Low), and rises at time t1 after the time when the AC power supply voltage Pw zero-crosses in the -180 ° phase (zero-cross timing). Becomes inactive (High).

The relay contact signal Sk is a signal for detecting the current between the relay contacts (between the two contacts of the relay contact 24), and when the relay contact 24 is closed and a current flows through the relay contact 24, it falls and becomes inactive (Low). When the relay contact 24 opens and the current of the relay contact 24 becomes 0, the relay contact 24 rises and becomes active (High).

The relay contact signal generation unit 16 is a relay contact when the relay contact 24 is closed and the current of the relay contact 24 momentarily becomes 0 at the timing when the direction of the current of the relay contact 24 changes. The signal Sk is configured to be inactive (ie, maintain Low). In the following, the timing at which the relay contact signal Sk rises and becomes active (High) is set as the time tx.

The relay control signal Sc rises from the time t0 to the time t2 after the delay time Tp has elapsed, and becomes active (High). Since the relay contact drive unit 18 drives (opens) the relay contact 24 in response to the rise (activation) of the relay control signal Sc, the timing at which the relay contact 24 actually opens is the delay time Tp (reference time). It is determined by the time difference between t0 and the time t2 at which the relay control signal Sc is activated).

FIG. 3 is an explanatory diagram of a zero cross pulse (ZP2). Regarding the zero cross pulse ZP2, it falls at time t3 and becomes active (Low), and after the time t5 (zero cross timing) at which the AC power supply voltage Pw zero crosses at 0 ° phase, it rises at time t7 and becomes inactive (High). Become.

The zero-cross signal generation unit 15 generates a zero-cross signal Sp that is active during a period in which the AC power supply voltage Pw is a value that does not cause discharge between the relay contacts (from Vm, which is a negative voltage, to Vn, which is a positive voltage). The discharge here is a phenomenon in which a current exceeding a magnitude assumed at each contact is generated between two separated contacts of the relay contact 24, and is typically an arc discharge (electric arc). The period from the time t3 when the AC power supply voltage Pw becomes Vm to the time t7 when the AC power supply voltage Pw becomes Vn is the active period Ts of the zero cross signal Sp.

As shown in FIG. 3, the times t4 and t6 are set between the time t3 and the time t7. The length of the active period Ts is equal to the width Tw of the zero cross pulse, t4 = t3 + Tw × B, t5 = t3 + Tw × 0.5, t6 = t3 + Tw × C, t7 = t3 + Tw × 1, period Ta before time t3, time t3 ~ T4 is defined as period Tb, time t4 to t6 is defined as period Tg, time t6 to t7 is defined as period Tc, and time t7 is defined as period Td. The coefficients B and C are 0 <B <C <1, and for example, B = 0.2 and C = 0.8.

When the time tx is included in the period Ta (t2 <tx ≦ t3), the opening timing of the relay contact 24 deviates from the active period Ts (shifts in the advancing direction), so that the relay contact 24 may be discharged. high. When the time tx is included in the period Tb (t3 <tx ≦ t4), since the opening timing of the relay contact 24 is within the active period Ts of the zero cross signal Sp, no discharge occurs, but it deviates from the target period Tg (in the traveling direction). It is out of alignment). When the time tx is included in the period Tg (t4 <tx ≦ t6), the opening timing of the relay contact 24 is within the target period Tg. When the time tx is included in the period Tc (t6 <tx≤t7), since the opening timing of the relay contact 24 is within the active period Ts, no discharge occurs, but it deviates from the target period Tg (shifts in the delay direction). .. When the time tx is included in the period Td (tx> t7), the opening timing of the relay contact 24 deviates from the active period Ts (shifts in the delay direction), so that there is a high possibility that the relay contact 24 is discharged.

When the time tx is included in the period Ta, the period Tb, the period Tc, and the period Td, the control unit 17 corrects the delay time Tp of the relay control signal Sc when the relay contact 24 is opened next time, and the time tx Is included in the target period Tg, the delay time Tp is not corrected the next time the relay contact 24 is opened.

FIG. 4 is a flowchart showing a relay control signal generation process (when the relay contact is opened) according to the embodiment. The control unit 17 performs the steps S1 to S12 of FIG. In step S1, the time tx (previous tx) and delay time Tp (previous Tp) when the relay contact 24 was opened last time are read, and in step S2, it is determined whether or not the previous tx is later than the time t3. To do. If NO (time tx is included in the period Ta) in step S2, the process proceeds to step S3, and the relay control signal Sc is set to a value longer than the previous Tp by the correction value Ua (for example, several tens of microseconds) as the current Tp. To generate.

If YES in step S2, the process proceeds to step S4, and it is determined whether or not the previous tx is after the time t4. If NO (time tx is included in the period Tb) in step S4, the process proceeds to step S5, and the relay control signal Sc is set as the current Tp with a value longer than the previous Tp by the correction value Ub (for example, several microseconds). Generate.

If YES in step S4, the process proceeds to step S6, and it is determined whether or not the previous tx is after the time t6. If NO (time tx is included in the target period Tg) in step S6, the process proceeds to step S7, and the relay control signal Sc is generated with the same value as the previous Tp as the current Tp.

If YES in step S6, the process proceeds to step S8, and it is determined whether or not the previous tx is after the time t7. If NO (time tx is included in the period Tc) in step S8, the process proceeds to step S9, and the relay control signal Sc is set as the current Tp with a correction value Uc (for example, several microseconds) shorter than the previous Tp. Generate.

If YES in step S8 (time tx is included in the period Td), the process proceeds to step S10, and the relay control signal is set to a value shorter than the previous Tp by the correction value Ud (for example, several tens of microseconds) as the current Tp. Generate Sc.

The correction values Ua, Ub, Uc, and Ud may be values determined according to the width Tw of the zero cross pulse, may be a predetermined constant value, and Ua> Ub, Ud> Uc. The reference of each time can be, for example, time t0 (starting point of zero cross pulse ZP1).

After steps S3, S5, S7, S9, and S10, the current time tx is detected in step S11, and the current time tx and the current delay time Tp are stored in step S12. Even if the time tx deviates from the target period Tg, the time tx can be returned (converged) to the target period Tg by performing the series of steps of FIG. 4 one or more times.

Regarding step S3, when the relay contact 24 is opened before the time t3, the relay contact signal Sk is not activated (maintains inactive Low) due to the occurrence of discharge even though the contact 24 is structurally open. In this case, the relay contact signal Sk becomes active (detection of time tx) at the timing when the discharge is eliminated (substantially, the time t3 when the AC power supply voltage Pw becomes Vm). In this way, when the time tx is at or before the time t3 (the time tx is included in the period Ta), the time when the relay contact 24 is actually opened cannot be grasped, and the discharge period becomes close to 1/2 cycle. Therefore, the correction value (Ua) of the delay time Tp is increased.

Regarding step S10, when the relay contact 24 is opened after the time t7, the relay contact signal Sk is not activated (maintains the inactive Low) due to the generation of the discharge even though the contact 24 is structurally open. ), In this case, the relay contact signal Sk becomes active at the timing when the discharge is eliminated (substantially, the timing at which the next zero cross pulse ZP3 rises) (detection of time tx). In this way, when the time tx is later than the time t7 (the time tx is included in the period Td), the time when the relay contact 24 actually opens cannot be detected, and the discharge period becomes close to 1/2 cycle. Therefore, the correction value (Ud) of the delay time Tp is increased.

According to this embodiment, even when the amplitude of the AC power supply voltage Pw fluctuates, the period in which the AC power supply voltage Pw is a value (Vm to Vn) that does not cause discharge between the relay contacts and the active period Ts of the zero cross signal Sp. Matches with. For example, as the amplitude of the AC power supply voltage Pw increases, the active period Ts shortens accordingly. Therefore, the control unit 17 generates a relay control signal Sc that opens the relay contact 24 within the active period Ts (target period Tg), so that the discharge does not occur when the relay contact 24 is opened, and the relay contact 24 is eliminated. Deterioration can be suppressed.

Further, the relay contact signal generation unit 16 is configured to generate a relay contact signal Sk that maintains a constant level (Low) regardless of the value of the AC power supply voltage Pw during the period when the relay contact 24 is closed. Therefore, the control unit 17 can easily and accurately detect the time tx.

In FIGS. 2 to 4, the target period Tg is set to the time t4 to t6 in consideration of the fluctuation of Vm / Vn (change in which the absolute value becomes smaller) due to the secular change of the relay contact, but the present invention is not limited to this. .. The target period may be matched with the active period Ts (time t3 to time t7) of the zero cross signal Sp.

FIG. 5 is a circuit diagram showing a configuration example of the zero-cross signal generation unit. The zero-cross signal generation unit 15 includes a first input terminal X1 connected to one end of the AC power supply 40, a second input terminal X2 connected to the other end of the AC power supply 40, an output terminal Y, resistors R1 to R7, and the like. The PNP bipolar transistor Q1, Q2, Q4 and the NPN bipolar transistor Q3 are included.

The first input end X1 is connected to the emitter of the transistor Q1, the base of the transistor Q2, and the emitter of the transistor Q4, the second input end X2 is connected to the emitter of the transistor Q2 via the resistor R2, and the output end Y is , Connected to the collector and control unit 17 of the transistor Q4.

The emitter of the transistor Q2 is connected to the base of the transistor Q1 and is connected to the first input terminal X1 via the resistor R1. The collector of the transistor Q2 is connected to the collector of the transistor Q1 and is connected to the base of the transistor Q3 via the resistor R3. The base of the transistor Q3 is grounded via the resistor R4, the emitter of the transistor Q3 is grounded, and the collector of the transistor Q3 is connected to the base of the transistor Q4 via the resistor R6. The base of the transistor Q4 is connected to the first input terminal X1 via the resistor R5, and the collector of the transistor Q4 is grounded via the resistor R7.

In the zero-cross signal generation unit 15, when the AC power supply voltage Pw is Vm to Vn (a value that does not cause discharge between the relay contacts), the transistors Q1, Q2, Q3, and Q4 are turned off, and the output terminal Y is active (the output terminal Y is active (value). Low), and when the AC power supply voltage Pw is other than Vm to Vn, the transistors Q1, Q2, Q3, and Q4 are turned on, and the output terminal Y is inactive (High).

The values Vm to Vn of the AC power supply 40 that does not cause discharge between the relay contacts are set based on the characteristics of the load 22 and the characteristics of the relay contacts 24 (material, distance between contacts, contact area, etc.). For example, if Vm = -8 [V], Vn = +8 [V], and the on-voltages of the transistors Q1 and Q2 are 0.6 [V], then 8 × the resistance value of the resistor R1 / (the resistance value of the resistor R1 +). Since the relationship of resistance R2 resistance value) = 0.6 is established, the resistance value of R1: the resistance value of R2 = 3:37 may be set.

Hereinafter, a case where the relay contact 24 is closed will be described.

FIG. 6 is a timing chart showing the operation of the electric device according to the embodiment (when the relay contact is closed). The zero-cross signal Sp in FIG. 6 includes a zero-cross pulse ZP10 corresponding to the −180 ° phase of the AC power supply voltage Pw and a zero-cross pulse ZP11 corresponding to the 0 ° phase of the AC power supply voltage Pw.

The zero-cross pulse ZP10 falls at time t10 (reference timing), becomes active (Low), and rises at time t11 after the time when the AC power supply voltage Pw zero-crosses in the -180 ° phase (zero-cross timing). Becomes inactive (High). In the following, the timing at which the relay contact signal Sk falls and becomes inactive (Low) is set as the time ty.

The relay control signal Sc falls after the delay time Tq elapses from the time t10, and becomes inactive (Low). Since the relay contact drive unit 18 drives (closes) the relay contact 24 in response to the fall (deactivation) of the relay control signal Sc, the timing at which the relay contact 24 actually closes is determined by the delay time Tq. ..

FIG. 7 is an explanatory diagram of a zero cross pulse (ZP11). Regarding the zero cross pulse ZP11, it falls at time t13 and becomes active (Low), and after the time t15 (zero cross timing) at which the AC power supply voltage Pw zero crosses at 0 ° phase, it rises at time t17 and becomes inactive (High). Become.

The zero-cross signal Sp is active during a period in which the AC power supply voltage Pw is a value (from Vm, which is a negative voltage, to Vn, which is a positive voltage) that does not cause discharge between the relay contacts. The period from the time t13 when the AC power supply voltage Pw becomes Vm to the time t17 when the AC power supply voltage Pw becomes Vn is the active period Ts of the zero cross signal Sp.

As shown in FIG. 7, the times t14 and t16 are set between the time t13 and the time t17. The length of the active period Ts is equal to the width Tw of the zero cross pulse, t14 = t13 + Tw × F, t15 = t13 + Tw × 0.5, t16 = t13 + Tw × J, t17 = t13 + Tw × 1, period Te before time t13, time t13. ~ T14 is defined as a period Tf, times t14 to t16 are defined as a period Tr, times t16 to t17 are defined as a period Tj, and time t17 is defined as a period Tk. The coefficients F and J are 0 <F <J <1, and for example, F = 0.2 and J = 0.8.

When the time ty is included in the period Te (t12 <ty ≦ t13), the closing timing of the relay contact 24 is out of the active period Ts (shifted in the advancing direction), which is caused by the bounce BT of the relay contact 24. There is a high risk of discharge. When the time ty is included in the period Tf (t13 <ty ≦ t14), since the closing timing of the relay contact 24 is within the active period Ts, no discharge occurs, but it deviates from the target period Tr (shifts in the advancing direction). .. When the time ty is included in the period Tr (t14 <ty ≦ t16), the closing timing of the relay contact 24 is within the target period Tr. When the time ty is included in the period Tj (t16 <ty ≦ t17), since the closing timing of the relay contact 24 is within the active period Ts, no discharge occurs, but it deviates from the target period Tr (shifts in the delay direction). .. When the time ty is included in the period Tk (ty> t17), the closing timing of the relay contact 24 deviates from the active period Ts (shifts in the delay direction), so that the discharge caused by the bounce BT of the relay contact 24 occurs. Highly likely to occur.

When the time ty is included in the period Te, the period Tf, the period Tj, and the period Tk, the control unit 17 corrects the delay time Tq of the relay control signal Sc when the relay contact 24 is closed next time, and the time ty. Is included in the period Tr, the delay time Tq is not corrected the next time the relay contact 24 is closed.

FIG. 8 is a flowchart showing a relay control signal generation process (when the relay contact is closed) according to the embodiment. The control unit 17 performs the steps S101 to S112 of FIG. In step S101, the time ty (previous ty) and the delay time Tq (previous Tq) when the relay contact 24 was closed last time are read, and in step S102, it is determined whether or not the previous ty is after the time t13. To do. If NO (time ty is included in the period Te) in step S102, the process proceeds to step S103, and the relay control signal Sc is set to a value longer than the previous Tq by the correction value Ue (for example, several tens of microseconds) as the current Tq. To generate.

If YES in step S102, the process proceeds to step S104, and it is determined whether or not the previous ty is after the time t14. If NO (time ty is included in the period Tf) in step S104, the process proceeds to step S105, and the relay control signal Sc is set as the current Tq with a correction value Uf (for example, several microseconds) longer than the previous Tq. Generate.

If YES in step S104, the process proceeds to step S106, and it is determined whether or not the previous ty is after the time t16. If NO (time ty is included in the period Tr) in step S106, the process proceeds to step S107, and the relay control signal Sc is generated with the same value as the previous Tq as the current Tq.

If YES in step S106, the process proceeds to step S108, and it is determined whether or not the previous ty is after the time t17. If NO (time ty is included in the period Tj) in step S108, the process proceeds to step S109, and the relay control signal Sc is set as the current Tp with a value shorter than the previous Tq by the correction value Uj (for example, several microseconds). Generate.

If YES in step S108 (time ty is included in the period Tk), the process proceeds to step S110, and a value shorter than the previous Tq by a correction value Uk (for example, several tens of microseconds) is set as the current Tq and the relay control signal. Generate Sc.

The correction values Ue, Uf, Uj, and Uk may be values determined according to the width Tw of the zero cross pulse, may be a predetermined constant value, and Ue> Uf, Uk> Uj.

After steps S103, S105, S107, S109, and S110, the current time ty is detected in step S111, and the current time ty and the current delay time Tq are stored in step S112. The reference of each time can be, for example, the time t10 (the start end of the zero cross pulse ZP10).

According to this embodiment, even when the amplitude of the AC power supply voltage Pw fluctuates, the period in which the AC power supply voltage Pw is a value (Vm to Vn) that does not cause discharge between the relay contacts and the active period Ts of the zero cross signal Sp. Matches with. For example, as the amplitude of the AC power supply voltage Pw increases, the active period Ts shortens accordingly. Therefore, the control unit 17 generates a relay control signal Sc that closes the relay contact 24 within the active period Ts (target period Tr), so that the discharge caused by the bounce of the relay contact 24 is eliminated and the relay contact is eliminated. The deterioration of 24 can be suppressed.

In FIGS. 6 to 8, the target period Tr is set to the time t14 to t16 in consideration of the fluctuation of Vm / Vn (change in which the absolute value becomes smaller) due to the secular change of the relay contact, but the present invention is not limited to this. .. The target period may be matched with the active period Ts (time t13 to time t17) of the zero cross signal Sp.

Each of the above embodiments is for purposes of illustration and description, not for limitation. Based on these examples and explanations, it will be apparent to those skilled in the art that many variants are possible.

15 Zero cross signal generator 16 Relay contact signal generator 17 Control unit 18 Relay contact drive unit 22 Load 24 Relay contact 30 Electrical equipment 40 AC power supply Sp Zero cross signal Sk Relay contact signal Sc Relay control signal Target period Tg ・ Tr

Claims (6)

A load, a relay contact, a zero cross signal generator that generates a zero cross signal according to the value of the AC power supply voltage, a relay contact signal generator that generates a relay contact signal indicating an electrical state between the relay contacts, and a relay. An electrical device including a control unit that generates a control signal.
The zero-cross signal becomes active during a period in which the AC power supply voltage is a value that does not cause discharge between the relay contacts.
The control unit is characterized in that the information obtained from the relay contact signal when the relay contact is previously opened is used to generate a relay control signal that opens the relay contact during the active period of the zero cross signal. Electrical equipment. The control unit is characterized in that the information obtained from the relay contact signal when the relay contact is previously closed is used to generate a relay control signal that closes the relay contact during the active period of the zero cross signal. The electric device according to claim 1. The electrical device according to claim 1 or 2, wherein the active period is set based on the characteristics of the load and the characteristics of the relay contact. Any one of claims 1 to 3, wherein the control unit is set within the active period and generates a relay control signal such that the relay contact opens in a target period shorter than the active period. Electrical equipment described in. Based on the information, the control unit determines that the timing at which the relay contact was opened last time is out of the target period, and the time difference between the reference timing and the timing at which the relay control signal is activated. The delay time is changed from the previous value, and when it is determined that the timing at which the relay contact was opened last time is included in the target period, the delay time is made the same as the previous value. The electric device according to claim 4. The electric device according to any one of claims 1 to 5, wherein the relay contact signal maintains the same level regardless of the value of the AC power supply voltage during the period when the relay contact is closed. ..

Images