JPH10241485A - Zero crossing closing power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize zero crossing power supply closing simply and at a low cost using a mechanical relay but not a semiconductor element such as TRIAC, thyristor, or the like. SOLUTION: A relay operation required time Tb after giving a drive command to a relay 24 until the closing of contacts 2a and an elapsed time Ta from zero crossing to a power supply device closing command are measured. The sum time of the elapsed time Ta and the relay operation required time Tb is subtracted from the closest value (n) τ to the sum time among values obtained by multiplying an AC period τ by an integer (n). The drive command is given to the relay 24 delaying by an operation adjustment time nτ-(Ta+Tb) obtained through the subtraction after receiving the power supply device closing command so as to conduct zero crossing power supply closing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zero-cross power supply device which enables a simple and inexpensive power-on by using a mechanical relay instead of a semiconductor device such as a triac or thyristor.

[0002]

2. Description of the Related Art Many television receivers receive a remote command from a remote control transmitter and turn on a main power supply. A microprocessor for receiving and decoding a remote command must always be in a standby state. For this reason, a configuration is often adopted in which a sub power supply for a microprocessor is always kept operating. A 5 V output three-terminal regulator or the like with low power consumption is used for the sub power supply. The main power supply for supplying necessary DC power to each part in the receiver is, for example, obtained by smoothing a full-wave rectified output of a commercial AC power supply. A switching power supply that switches a given direct current to boost the voltage is often used.

FIG. 4 is a circuit diagram showing an example of a conventional power supply device. A power supply device 1 shown in FIG. 1 is for a television receiver, and includes a main power supply and a sub power supply. The main power supply uses an AC current supplied from a commercial AC power supply via an AC power supply plug 2 to a contact 4 a of the fuse 3 and the relay 4.
The rectified current is applied to the full-wave rectifier circuit 5 via the rush current limiting resistor Rr, and the rectified current is smoothed by the smoothing capacitor Cm. Is supplied. The auxiliary power supply supplies an alternating current supplied from the AC power supply plug 2 to the primary side of the transformer 7 via the fuse 3 and rectifies the current rectified by the full-wave rectifier circuit 8 connected to the secondary side of the transformer 7. Resistance Rs and smoothing capacitor C
s.
It is configured to output a DC voltage maintained at a constant V.

In this embodiment, the output voltage of the three-terminal regulator 9 is supplied to the power supply terminal Vcc of the microprocessor 10 to keep the microprocessor 10 in an operating state. The relay 4 includes an exciting coil 4c energized and excited by a relay driver 4d connected to a relay drive output port of the microprocessor 10, a reverse blocking diode 4b connected by connecting both ends of the exciting coil 4c, and an exciting coil 4c. The normally open contact 4 that is driven to open and close in response to excitation and demagnetization
and a normally open contact 4a when an operation time peculiar to each relay 4 has elapsed since the relay drive signal was output from the relay drive output port of the microprocessor 10.
Is to be closed.

The above-mentioned conventional power supply device 1 has a configuration in which the main power supply is turned on and off irrespective of the zero cross of the commercial AC power supply, that is, the timing at which the output voltage of the AC power supply crosses zero volts. As a result, a current flows, so that the rating of the fuse 3 and the rating of the inrush current limiting resistor Rr must be large enough to withstand the maximum expected inrush current, and the inrush current constitutes a main power supply. Since the element is subjected to stress due to excessive voltage or excessive current, there is a problem that it is disadvantageous in terms of component life and operation reliability.

Therefore, a power supply device using a semiconductor element has been proposed so that the power supply is turned on in accordance with the zero crossing.
It has come to be used for various household electrical appliances. FIG. 5 is a circuit diagram showing an example of this type of conventional power supply device. The power supply device 11 shown in the figure realizes zero-cross power supply using a thyristor CR and a triac BCR.

First, when the switch 12 is closed and a power-on command is issued, the light emitting diode 13a in the photocoupler 13 that is energized via the resistor R1 is turned on, and the phototransistor 13b is turned on. As a result, the transistor Q1 in the zero volt switch circuit 14, in which the resistor R2 and the phototransistor 13b are connected to the base, switches from the conductive state to the cutoff state. On the other hand, zero volt detection is performed by the resistors R3 and R4 and the transistor Q2, and when the detected voltage is within a certain voltage (several volts), the transistor Q
2 is also in a blocking state. Therefore, a gate current flows through the thyristor CR via the resistor R5, and the thyristor CR is turned on. When the thyristor CR is turned on, the triac B is connected via the bridge-connected rectifier diodes D1 to D4.
A current flows through the CR gate. As a result, the triac BCR conducts, and power is supplied to the load 15 from the AC power supply 16.

When the switch 12 is turned on, the AC power
For a phase other than zero volts at 6, this is the resistance R3
It is determined by R4 and the transistor Q2. When the transistor Q2 is turned on, the thyristor CR is turned off, and the triac BCR is also turned off. On the other hand, when the switch 12 is opened, the phototransistor 13b is turned off and the transistor Q1 is turned on, so that the thyristor CR is not turned on. However, a resistor R6 is connected to the gate of the triac BCR so that the sensitivity of the triac BCR can be adjusted so that the triac BCR is not triggered by the leakage current of the zero volt switch circuit 14 while the thyristor CR is non-conductive. Note that the resistor R7 and the capacitor C constitute an absorber for absorbing a surge voltage.

[0009]

The above-mentioned conventional power supply device 1
Reference numeral 1 denotes a configuration for controlling a phase in which a rectifying element such as a thyristor CR or a triac BCR enters an on state from an off state with respect to an AC power supply 16 that supplies power to a load 15. Since many semiconductor elements are used, the circuit configuration is Since it is very complicated and switching noise and leakage current are inevitably generated, there is a problem that countermeasures against interference with other circuits must be taken. Further, since the zero volt switch circuit 14 is provided on the AC primary side, it is necessary to ensure a sufficient space distance of the printed wiring board for safety reasons, and such restrictions on the mounting surface and noise suppression requirements cannot be ignored. Therefore, there has been a problem that designing and manufacturing are not easy and it is difficult to reduce manufacturing costs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to enable simple and inexpensive zero-cross power supply using a mechanical relay instead of a semiconductor device such as a triac or thyristor. is there.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention detects a power supply connected to an external AC power supply via a relay contact and a zero crossing where the output voltage of the AC power supply crosses zero volts. A zero-cross detector
The AC cycle is measured from the output of the zero-cross detector, and the relay operation required time from when a drive command is given to the relay until the contact is closed and the elapsed time from the zero-cross to the power-on command are measured. Subtracting the total time of the elapsed time and the relay operation required time from a value closest to the total time by a value obtained by multiplying the AC cycle by an integer, and an operation adjustment time obtained by the subtraction after receiving the power-on command. Control means for giving a drive command to the relay with only a delay and turning on the zero-cross power.

The present invention is also characterized in that the control means measures the required operation time of the relay each time the power is turned on, and updates and registers the latest required operation time in a memory. A drive command for the relay, and a time counter for counting the time until the contact of the relay is closed, or the zero-cross detector detects a half-wave rectified output of the AC power supply at a predetermined threshold. It is characterized by including a constant voltage diode that slices with a voltage and outputs a rectangular wave voltage.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a circuit diagram showing an embodiment of a zero-cross power supply device according to the present invention.
3 is a flowchart for explaining the operation of the microprocessor shown in FIG. 1, and FIG. 3 is a signal waveform diagram of each part of the circuit shown in FIG.

A zero-cross power supply device 21 shown in FIG. 1 realizes a zero-cross power supply for turning on the power supply when the output voltage of an AC power supply crosses zero volts with a simple circuit configuration. A zero-cross detector 22 and a relay contact closing detecting means are added, and the operation software of the microprocessor 23 is improved for zero-cross input. The target of the zero-cross input is not the sub-power supply for supplying the operating power supply Vcc to the microprocessor 23, but the main power supply for supplying various DC power supplies to the respective circuits of the television receiver. The main power supply here is a full-wave rectifier circuit 5 connected to an AC power supply via a contact 24a of a relay 24, a smoothing capacitor Cm for smoothing the full-wave rectified output of the full-wave rectifier circuit 5, and a smoothing capacitor Cm. And a switching circuit 6 for boosting the output by switching. A sub-power supply for supplying operating power to the microprocessor 23 is mainly composed of a three-terminal regulator 9, and is connected to an AC power supply via a transformer 7, a full-wave rectifier circuit 8, a resistor Rs, and a smoothing capacitor Cs.

The zero-cross detector 22 is a full-wave rectifier 8
Zener diode (constant-voltage diode) ZD that slices the half-wave rectified output of the AC power supply with a predetermined threshold voltage.
Is shunt-connected to one end of the detection resistor Rz. The square wave voltage output from the Zener diode ZD is
The signal is supplied to the zero cross signal input port of the microprocessor 23, and is shaped into an edge pulse inside the microprocessor 23. That is, the microprocessor 23 measures the AC cycle from the output of the zero-crossing detector 22 and supplies the relay operating time Tb from when the drive command is given to the relay 24 to when the contact 24a is closed and the power supply from the zero-crossing. Elapsed time T until injection command
It serves to measure a. In this embodiment, in order to measure the relay operation required time Tb, a relay 24 having two normally open contacts 24a is used, and one normally open contact 24a is used.
Is connected to the power supply line to the full-wave rectifier circuit 5, and the other normally open contact 24a is connected to the input port for detecting the relay operation of the microprocessor 23. 24c is a relay 24
And 24b is a reverse blocking diode connected by connecting both ends of the exciting coil 24c. Rp is a pull-up resistor for suspending the relay operation detection input port to the power supply Vcc. As the relay driver 24d,
It is possible to use the same circuit 4d as before.

The microprocessor 23, which is a control means, measures the operation time Tb of the relay 24 every time the power is turned on, and stores a memory (not shown) for updating and registering the latest operation time Tb. A time counter (not shown) for measuring the period τ is built in. As will be described later, the total time T of the elapsed time Ta from the zero crossing to the power-on command and the relay operation required time Tb is determined by the AC period τ. Is subtracted from the value nτ closest to the total time T by a value obtained by multiplying by an integer (n), and an operation adjustment time ΔT (= nτ−T) obtained by the subtraction after receiving a power-on command.
A drive command is given to the relay 24 with only a delay, thereby turning on the zero-cross power.

Hereinafter, the operation of the zero-cross power supply device 21 having the above configuration will be described with reference to the flowchart shown in FIG.
This will be described with reference to the signal waveforms of the respective circuits shown in FIG. First,
3B synchronized with the AC cycle supplied from the zero-cross detector 22 in the step (101) shown in FIG.
Is shaped into an edge pulse shown in FIG. 3C inside the microprocessor 23, and the time counter measures the period of this edge pulse to detect the zero-cross period τ. When the zero-cross period τ is determined, it is determined in a subsequent determination step (102) whether or not a power-on command has been input to the power-on command input port. When it is determined that the power-on command has been input, the elapsed time Ta from the edge pulse output at the falling edge of the square wave pulse to the input of the power-on command is counted as the number of 1 msec clock pulses generated by the clock counter. Also, when the power is turned on last time, the relay operation required time Tb measured by the microprocessor 23 is read from the memory,
A time T (= Ta + Tb) obtained by adding the times Ta and Tb is obtained.

The relay operation required time Tb has individual differences between television receivers and changes with time. Therefore, steps (107) to (110) described later are performed so that the data is updated to the latest data each time the power is turned on. ) Is prepared. On the other hand, the time Ta should be considered to be a completely random value because the power-on command by the remote controller operation or the like is issued regardless of the AC cycle.

Next, in the subsequent decision step (104), the time T and the period τ are compared in magnitude. If T ≦ τ, the process proceeds to step (105), and if T> τ, the process proceeds to step (106). ). That is, in the step (105), the calculation of τ-T is performed, and the operation adjustment time ΔT1 (= τ-T) necessary for turning on the power in synchronization with the zero cross in the next cycle is calculated. Since this calculation is performed almost instantaneously, a relay drive signal is output as shown in FIG. 3 (F) when the operation adjustment time ΔT1 has elapsed since the power-on command was received. As a result, when the time Tb has elapsed from the relay drive signal, that is, in FIG.
As shown in (G), the power is turned on just in synchronization with the zero cross in the next cycle, and the zero cross is realized.

On the other hand, in step (106), 2T
The operation adjustment time ΔT2 (= 2) required for performing the calculation of −τ and turning on the power in synchronization with the zero cross of the next next cycle.
T−τ) is calculated. Since this calculation is performed almost instantaneously, the operation adjustment time Δ
When the time T2 has elapsed, a relay drive signal is output as shown in FIG. As a result, when the time Tb elapses from the relay drive signal, that is, as shown in FIG. 3 (I), the power is turned on just in synchronization with the zero cross in the next next cycle, and the zero cross is realized.

As shown in step (107), the time Tb from the power-on command to the actual start of the main power supply is measured every time as the relay operation required time, and this relay operation required time Tb is stored. The contents of the memory are
Always updated with the latest data. That is, the time Tb from the output of the relay drive signal to the closing of the normally open contact 24a is measured by the time counter, and in the determination step (109) subsequent to the determination step (108), the relay operation required for the last use is determined. It is determined whether or not the time matches the time Tb. If they match, the process is terminated as it is, but if they are different, in step (110), the relay operation required time Tb found this time is stored in the memory as the latest time data. Used as data required for input.

As described above, according to the above-mentioned zero-cross power supply device 21, the contact 24 of the relay 24 is connected to the external AC power supply.
a, a main power supply connected via a, and a zero-cross detector 22 for detecting a zero-cross where the output voltage of the AC power crosses zero volts. A microprocessor 23 measures the AC period τ from the output of the zero-cross detector 22,
The relay operation required time Tb from when the drive command is given to the relay 24 until the contact 24a is closed and the elapsed time Ta from the zero crossing to the power-on command are measured, and the elapsed time Ta and the relay operation required time Tb are measured. Is subtracted from the value nτ closest to the total time by a value obtained by multiplying the AC cycle τ by an integer (n), and the operation adjustment time nτ- (Ta + Tb) obtained by the subtraction after receiving the power-on command. Since a drive command is given to the relay 24 and the zero-cross power is turned on, the total time Ta + Tb of the elapsed time Ta from the zero cross to the power-on command and the relay operation required time Tb is shorter than the AC cycle τ. , A relay drive signal is output with a delay adjustment time τ− (Ta + Tb) obtained as a difference between the total time Ta + Tb and the AC cycle τ. Synchronization with Rokurosu power can be poured in, and if the total time Ta + Tb between the elapsed time Ta and relay operation time required Tb until power-on command is longer than the alternating period τ from the zero crossing, the total time T
A relay drive signal is output with a delay adjustment time 2τ− (Ta + Tb) obtained as a difference between a + Tb and a double AC cycle 2τ, and the power can be turned on in synchronization with the zero crossing of the next next cycle. Accordingly, the zero-cross power can be turned on with a simple configuration using the relay 24 and the zero-cross detector 22. In addition, since conventional parts can be used almost as they are, power can be turned on at zero crossing of a commercial AC power supply with an inexpensive and simple circuit, and the inrush current at the time of turning on the power is suppressed. Since the rating of the inrush current limiting resistor Rr can be reduced, and stress due to excessive voltage or excessive current is not applied to the circuit elements constituting the main power supply, the reliability of the device can be greatly improved. The use of a semiconductor device such as a triac or triac eliminates the emission of radiated noise, eliminating the need for countermeasures such as noise interference. Since the delay time is adjusted in accordance with, general versatility can be provided.

The microprocessor 23 measures the operation time Tb of the relay 24 every time the power is turned on, and updates and registers the latest operation time Tb in the memory. , Regardless of individual differences of the relay 24 itself and aging of the relay operation characteristics, etc., the zero-cross power supply can always be realized based on the most reliable time data. Even if 24 is replaced, the delay time is adjusted according to the characteristics of the parts used, so that versatility can be provided.

After the microprocessor 23 issues a drive command to the relay 24, the contact 2
4a has a time counter for measuring the time until it closes, so that the operation required time Tb of the relay 24 can be accurately measured with the time resolution of the time counter, thereby reducing the delay time required for turning on the zero-cross power. Accurate indexing and reliable zero-cross power supply is possible.

Further, a zero-crossing detector 22 slices the half-wave rectified output of the AC power supply with a predetermined threshold voltage and outputs a square-wave voltage.
Therefore, the half-wave rectified output of the AC power supply is sliced using the breakdown voltage of the constant voltage diode ZD as a threshold voltage, and a zero-cross is accurately detected with a rectangular wave voltage having a steep edge portion of the sliced voltage. Can be.

[0026]

As described above, according to the zero-cross input power supply device of the present invention, the power supply connected to the external AC power supply through the contact of the relay and the zero crossing where the output voltage of the AC power supply crosses zero volts are eliminated. A zero-cross detector is provided for detection, and the microprocessor measures the AC cycle from the output of the zero-cross detector, and also provides the relay operation time from when a drive command is given to the relay to when the contact is closed, and power on from the zero-cross. The elapsed time up to the command is measured, and the total time of the elapsed time and the time required for the relay operation is subtracted from the value closest to the total time by a value obtained by multiplying the AC cycle by an integer. A drive command is given to the relay with a delay of the obtained operation adjustment time, and the zero-cross power is turned on. If the total time of the elapsed time up to the ON command and the relay operation required time is shorter than the AC cycle, the relay drive signal is output with the delay adjustment time obtained as the difference between the total time and the AC cycle, and the next cycle is output. The power can be turned on in synchronization with the zero crossing. On the other hand, if the total time of the elapsed time from the zero crossing to the power-on command and the time required for the relay operation is longer than the AC cycle, the total time is twice as large as the AC. The relay drive signal is output with the delay adjustment time obtained as the difference from the cycle, and the power can be turned on in synchronization with the zero cross of the next cycle. This allows a simple configuration using a relay and a zero cross detector The power can be turned on with zero-cross power of the commercial AC power supply using an inexpensive and simple circuit because the existing parts can be used almost as is. It is possible to reduce the rating of the fuse and the rating of the rush current limiting resistor because the rush current when the power is turned on can be reduced. Since no stress is applied, the reliability of the equipment can be greatly improved.Since the use of semiconductor devices such as thyristors and triacs is not required, radiation noise is not emitted, and no countermeasures such as noise interference are required. Furthermore, even if parts such as relays are replaced during the after-sales service, the delay time is adjusted in accordance with the characteristics of the used parts, so that excellent effects such as versatility can be obtained.

Further, according to the present invention, the control means measures the relay operation time required each time the power is turned on and updates and registers the latest operation time in the memory. The zero-cross power supply can always be turned on based on the most reliable time data, regardless of individual differences of relays themselves or aging of relay operation characteristics, etc. Even so, since the delay time is adjusted according to the characteristics of the parts used, excellent effects such as versatility can be obtained.

Further, since the control means has a time counter for measuring the time from when the drive command is issued to the relay to when the contact of the relay is closed, the time required for the operation of the relay is measured by the time resolution of the time counter. This makes it possible to accurately measure the delay time required for turning on the zero-cross power supply, thereby achieving excellent effects such as being able to reliably turn on the zero-cross power supply.

Further, the zero-cross detector includes a constant voltage diode for slicing the half-wave rectified output of the AC power supply with a predetermined threshold voltage and outputting a rectangular wave voltage. The slice voltage is sliced with the breakdown voltage of the constant voltage diode as a threshold voltage, and an effect is obtained such that a zero-cross can be accurately detected with a rectangular wave voltage having a steep edge portion of the sliced voltage.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of a zero-cross power supply device according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the microprocessor shown in FIG. 1;

FIG. 3 is a signal waveform diagram of each part of the circuit shown in FIG.

FIG. 4 is a circuit configuration diagram showing an example of a conventional power supply device.

FIG. 5 is a schematic configuration diagram showing another example of a conventional power supply device.

[Explanation of symbols]

 2 AC power plug 3 Fuse Rr Inrush current limiting resistor 5 Full-wave rectifier circuit 6 Switching circuit 21 Zero cross power supply 22 Zero cross detector 23 Microprocessor 24 Relay 24a Normally open contact 24c Exciting coil 24d Relay driver

Claims (4)

[Claims] A power supply connected to an external AC power supply via a relay contact; a zero-cross detector for detecting a zero-cross where an output voltage of the AC power crosses zero volts;
The AC cycle is measured from the output of the zero-cross detector, and the relay operation required time from when a drive command is given to the relay until the contact is closed and the elapsed time from the zero-cross to the power-on command are measured. Subtracting the total time of the elapsed time and the relay operation required time from a value closest to the total time by a value obtained by multiplying the AC cycle by an integer, and an operation adjustment time obtained by the subtraction after receiving the power-on command. Control means for giving a drive command to the relay with a delay and turning on the zero-cross power. 2. The power supply according to claim 1, wherein said control means measures the time required for operating the relay each time the power is turned on, and updates and registers the latest time required for operation in a memory. 3. The control unit according to claim 1, wherein the control unit has a time counter for counting a time from when a drive command is issued to the relay to when a contact of the relay is closed. Zero cross input power supply. 4. The constant voltage diode according to claim 1, wherein the zero-cross detector slices a half-wave rectified output of the AC power supply with a predetermined threshold voltage and outputs a rectangular wave voltage. Zero crossing power supply.