JP5849216B2 - Load control device - Google Patents

Description

  The present invention relates to a two-wire load control device, and more particularly to a load switching circuit thereof.

  Conventionally, in order to control the on / off of loads such as lighting devices and ventilation fans, load control devices using non-contact switch elements such as triacs instead of 2-wire switches whose contacts are mechanically opened and closed (electronic Switch) has been put into practical use (see Patent Document 1). Such a load control device generally has a two-wire connection from the viewpoint of wiring saving, and is connected in series between a commercial power supply (AC power supply) and a load.

  FIG. 5 shows a circuit configuration of a conventional two-wire load control device 50 connected in series between a commercial power source 2 and a load 3 described in Patent Document 1. The load control device 50 includes a main opening / closing unit 51 and an auxiliary opening / closing unit 57 that control on / off of the load 3, a control unit 53 that controls conduction of the main opening / closing unit 51 and the auxiliary opening / closing unit 57, and a control unit 53. It consists of a power supply circuit for supplying drive power.

  The load control device 50 includes two load switching circuits in order to control on and off of a load 3 such as a lighting device. The auxiliary opening / closing part 57 is configured by using a thyristor 57a as a switch element, and when the load 3 is energized, the auxiliary opening / closing part 57 is first conducted to provide an energization path. The main opening / closing part 51 is configured using a triac 51a as a switching element, and provides a more stable energization path on the side closer to the load 3 than the auxiliary opening / closing part 57 after the auxiliary opening / closing part 57 is conducted.

  When the operation handle (SW) 4 for activating the load 3 is operated, the control unit 53 outputs a control signal, whereby the switch element 56c of the third power supply unit 56 is turned on, and the switch element 56b is turned on. To do. As a result, the current output from the rectifying unit 52 flows through the switch element 56b and charges the buffer capacitor 58. When the buffer capacitor 58 is charged, current flows through the Zener diode 56a to the gate of the thyristor 57a of the auxiliary opening / closing part 57, whereby the thyristor 57a becomes conductive. Since the thyristor 57a is connected between the output terminals of the rectifier unit 52, the current rectified by the rectifier unit 52 flows to the load 3 due to the conduction of the thyristor 57a. Since this current also flows through the gate of the triac 51a of the main switching unit 51, when the voltage becomes higher than the trigger voltage of the triac 51a, the triac 51a, that is, the main switching unit 51 becomes conductive. Once the main opening / closing part 51 becomes conductive (closed state), the current continues to flow. However, when the commercial current reaches the zero cross point, the triac 51a self-extinguishes and the main opening / closing part 51 becomes non-conductive (open state). Become. When the main opening / closing part 51 becomes non-conductive (open state), a current flows from the rectifying part 52 through the third power supply part 56 to the first power supply part 54, and an operation for securing the self-circuit power supply of the load controller 50 is performed. In other words, the self-circuit power supply securing of the load control device 50, the conduction of the auxiliary opening / closing part 57, and the conduction operation of the main opening / closing part 51 are repeated every half cycle of the alternating current.

JP 2008-97535 A

  By the way, thyristors and triacs generate so-called switching noise at the start of energization. In FIG. 6A, the broken line indicates the voltage waveform of the commercial power supply, and the solid line indicates the voltage waveform of the power supplied to the load. FIG. 6B is an enlarged view of a voltage waveform of power supplied to the load. As shown in FIGS. 6A and 6B, when switching noise due to thyristors or triacs occurs, the waveform of power supplied to the load 3 is disturbed due to switching noise. In the operation of the load 3, the influence due to the disturbance of the voltage waveform causes, for example, an instantaneous fluctuation of the brightness of the lighting device.

  The present invention has been made to solve the above-described problems of the conventional example, and an object of the present invention is to provide a load control device that reduces the switching noise of the triac constituting the main opening / closing section.

A load control device according to an aspect of the present invention includes a main switching unit in which a main electrode of a main switch element is connected in series to a commercial power source and a load, and controls supply of electric power to the load.
A rectifier connected between the main electrodes of the main switch element;
A control unit that controls on or off of the load according to an external signal;
A first power supply unit for stably supplying power to the control unit;
A second power supply unit that is supplied with power from both ends of the main opening / closing unit via a rectification unit and supplies power to the first power supply unit when the load is turned off;
A third power supply unit that is supplied with power from both ends of the main opening / closing unit via a rectification unit and supplies power to the first power supply unit when the load is turned on;
An auxiliary opening / closing portion connected between output terminals of the rectifying portion and conducting before the main opening / closing portion when supplying power to the load;
It said main switching unit uses a triac as the main switching device, when the triac terminal voltage decreases further Ru comprising an auxiliary power supply unit for reducing the switching noise to discharge electric charge.

  The auxiliary power supply unit is connected between the capacitor charged by the commercial power source, and both terminals of the capacitor and both terminals of the commercial power source, for preventing backflow when electric charge is discharged from the capacitor. Two diodes, a first switch element and a second switch element connected between both terminals of the capacitor and the T1 and T2 terminals of the triac, and a terminal voltage of the triac according to the phase of the commercial power supply When the voltage drops below the terminal voltage of the capacitor, conduction and non-conduction of the first switch element and the second switch element are performed so as to discharge charges from the capacitor so as to complement the terminal voltage of the triac. It is preferable to provide a switching circuit to be controlled.

  The auxiliary power unit includes a DC power source, a first switch element and a second switch element connected between a positive side of the DC power source, and a T1 terminal and a T2 terminal of the triac, a negative side of the DC power source, and the A third switch element and a fourth switch element connected between both terminals of a commercial power source, and the first switch element to the second switch element so that electric charges are discharged from the capacitor so as to complement the terminal voltage of the triac. It is preferable that a switching circuit for controlling conduction and non-conduction of the four switch elements is provided.

  According to the configuration of the present invention, when the triac terminal voltage is lowered when the triac terminal voltage is lowered, the charge is discharged from the auxiliary power supply unit, and the triac terminal voltage is recovered. As a result, switching noise is reduced, the voltage waveform of the power supplied to the load is stabilized, and for example, instantaneous fluctuations in brightness of the lighting device are reduced.

The circuit diagram which shows the basic concept of the load control apparatus which concerns on one Embodiment of this invention. The voltage waveform figure in the load control apparatus which concerns on this invention. The circuit diagram which shows the specific 1st structural example of the said load control apparatus. The circuit diagram which shows the specific 2nd structural example of the said load control apparatus. The circuit diagram which shows the structure of the conventional load control apparatus. (A) is a voltage waveform diagram which shows the problem of the conventional load control apparatus, (b) is an enlarged view of the part shown with the code | symbol A. FIG.

  A basic concept of a load control device 1 according to an embodiment of the present invention will be described with reference to FIG. The load control device 1 is connected in series with a commercial power source 2 and a load 3. The load control device 1 includes a main opening / closing part 11 and an auxiliary opening / closing part 17 that control ON / OFF of the load 3 and a control part 13 that controls conduction of the main opening / closing part 11 and the auxiliary opening / closing part 17 in the same manner as the conventional example. And a power supply circuit for supplying drive power to the control unit 13. The power supply circuit includes a rectifying unit 12, a first power supply unit 14 that stabilizes power supply to the control unit 13, a second power supply unit 15 that supplies power to the first power supply unit 14 when power to the load 3 is stopped, and a load 3 includes a third power supply unit 16 that supplies power to the first power supply unit 14 when power is supplied to the power supply 3. The main opening / closing part 11 includes a triac 11a as a main switch element. Moreover, the auxiliary | assistant opening / closing part 17 is provided with the thyristor 17a, for example, and the thyristor 17a is connected between the output terminals of the rectification | straightening part 12 comprised by the diode bridge. The first power supply unit 14 is a DC / DC converter that steps down the input direct current so that the output voltage is lower than the input voltage. Note that the configurations and operations of the second power supply unit 15 and the third power supply unit 16 are the same as those in the conventional example, and thus the description thereof is omitted.

  When the operation handle (SW) 4 for activating the load 3 is operated, the control unit 13 outputs a control signal, whereby the switch element 16c of the third power supply unit 16 is turned on, and the switch element 16b is turned on. To do. As a result, the current output from the rectifying unit 12 flows through the switch element 16 b and charges the buffer capacitor 18. When the buffer capacitor 18 is charged, the current flows through the Zener diode 16a to the gate of the thyristor 17a of the auxiliary opening / closing part 17, thereby making the thyristor 17a conductive. Since the thyristor 17a is connected between the output terminals of the rectifier unit 12, the current rectified by the rectifier unit 12 flows to the load 3 due to the conduction of the thyristor 17a. Since this current also flows through the gate of the triac 11a of the main switching unit 11, when the voltage becomes higher than the trigger voltage of the triac 11a, the triac 11a, that is, the main switching unit 11 becomes conductive. Once the main opening / closing part 11 becomes conductive (closed state), the current continues to flow. However, when the commercial current reaches the zero cross point, the triac 11a self-extinguishes and the main opening / closing part 11 becomes non-conductive (open state). Become. When the main opening / closing part 11 becomes non-conductive (open state), a current flows from the rectifying part 12 through the third power supply part 16 to the first power supply part 14, and the operation for securing the self-circuit power supply of the load control device 1 is performed. In other words, the self-circuit power supply securing of the load control device 1, the conduction of the auxiliary switching unit 17, and the conduction operation of the main switching unit 11 are repeated every half cycle of AC.

  The load control device 1 further includes an auxiliary power supply unit 19 that reduces switching noise of the triac 11a. FIG. 1 is a diagram for explaining the concept of the load control device 1 according to the present invention, and it is depicted that an auxiliary power supply unit 19 is provided in parallel with the T1 terminal and the T2 terminal of the triac 11a. The auxiliary power supply unit 19 is not limited to this place. The auxiliary power supply unit 19 functions to discharge electric charges and reduce switching noise when the terminal voltage of the triac 11a decreases. Therefore, as shown in FIG. 2, even if the terminal voltage of the triac 11 a fluctuates, the amount of decrease in the terminal voltage of the triac 11 a is supplemented by the charge discharged from the auxiliary power supply unit 19, and the power supplied to the load 3 The voltage waveform of becomes smooth. That is, the switching noise at the start of conduction of the triac 11a is reduced.

  FIG. 3 shows a specific first configuration example of the load control device 1. A series circuit of a capacitor 191 and two diodes 192 and 193 for preventing backflow is connected between both terminals 1a and 1b of the load control device 1 connected in series to the commercial power source 2 and the load 3. The first switch element (SW1) 194 and the second switch element (SW2) 195, such as transistors, are connected between both terminals of the capacitor 191 and the T1 terminal and T2 terminal of the triac 11a, respectively. The first switch element (SW1) 194 and the second switch element (SW2) 195 are controlled to be on (conductive) and off (non-conductive) by the switching circuit 196. The switching circuit 196 is connected to the voltage detection circuit 197, and the voltage detection circuit 197 detects the terminal voltage of the thyristor 17a. The auxiliary power supply unit 19 includes a capacitor 191, diodes 192 and 193, a first switch element 194 and a second switch element 195, a switching circuit 196, a first voltage detection circuit (voltage detection 1) 197, a second voltage detection circuit (voltage Detection 2) 198 or the like.

  The first voltage detection circuit 197 monitors the terminal voltage of the thyristor 17a, and the second voltage detection circuit 198 monitors the voltage of the commercial power source 2. The switching circuit 196 turns on and off the first switch element (SW1) 194 and the second switch element (SW2) 195 according to the combination of the voltage detection results of the first voltage detection circuit 197 and the second voltage detection circuit 198. Control timing. In the configuration example shown in FIG. 3, the switching circuit 196 and the control unit 13 are drawn as separate blocks. However, the switching circuit 196 may be integrated with the control unit 13 and configured by the same CPU or the like. In the configuration example shown in FIG. 3, the terminal voltage of the thyristor 17a and the phase of the commercial power supply 2 are monitored to control the on / off timing of the first switch element 194 and the second switch element 195. However, it is not limited to this. For example, the conduction and non-conduction of the thyristor 17a is controlled by the control signal from the control unit 13, and the ON / OFF timing of the first switch element 194 and the second switch element 195 is controlled based on the control signal. You may comprise as follows.

  For example, when the terminal 1a is at a high potential, the capacitor 191 is charged by turning on the first switch element 194 and turning off the second switch element 195. The same applies to the reverse case. The capacitor 191 is charged until the triac 11a becomes conductive. When the charging of the capacitor 191 is completed, the first switch element 194 is turned off and the second switch element 195 is turned on until the triac 11a becomes conductive. Then, the charge received by the capacitor 191 can be discharged. When the voltage output from the rectifying unit 12 becomes higher than the gate trigger voltage of the triac 11a, the triac 11a becomes conductive, and the current supplied to the load 3 flows through the triac 11a. When the triac 11a becomes conductive, the terminal voltage of the triac 11a varies as shown in FIG. When the terminal voltage of the triac 11a is lower than the terminal voltage of the capacitor 191, the charge is discharged from the capacitor 191 and attempts to supplement the decrease in the terminal voltage of the triac 11a. As a result, as shown in FIG. 2, the voltage waveform of the power supplied to the load 3 becomes gentle, and the switching noise at the start of conduction of the triac 11a is reduced.

  In addition, on the circuit configuration shown in FIG. 3, the auxiliary power supply unit 19 is provided on the side close to the commercial power supply 2 in the entire load control device 1. Therefore, the electric charge charged in the capacitor 191 also flows through the rectifier 12 to the thyristor 17a. Therefore, the switching noise of the triac 11a can be reduced, and the switching noise of the thyristor 17a can be reduced.

  FIG. 4 shows a specific second configuration example of the load control device 1. The auxiliary power unit 19 includes a DC power source 200 such as a battery, four switch elements (SW1 to SW4) 201 to 204, the switching circuit 196, the voltage detection circuit 197, and the like. The first switch element (SW1) 201 and the second switch element (SW2) 202 are connected between the plus side of the DC power supply 200 and the T1 terminal and T2 terminal of the triac 11a. The third switch element (SW3) 203 and the fourth switch element (SW4) 204 are connected between the negative side of the DC power source 200 and both terminals of the commercial power source 2. With the first switch element 201 and the third switch element 203 as one set and the second switch element 202 and the fourth switch element 204 as another set, they are simultaneously turned on (conductive) and turned off (non-conductive). The switching circuit 196 monitors the terminal voltage of the thyristor 17a and the phase of the commercial power supply 2, and controls on and off of these two sets of switch elements. When the terminal voltage of the triac 11a drops below the voltage of the DC power supply 200, the electric charge is discharged from the DC power supply 200 and attempts to supplement the decrease in the terminal voltage of the triac 11a. As a result, the same effect can be obtained by such a configuration.

  In the above embodiment, a full-wave rectifier circuit is used as the rectifier 12, but the present invention is not limited to this, and a half-wave rectifier circuit may be used. When the rectification unit 12 is a half-wave rectification circuit, two sets of the half-wave rectification circuit and the second power supply unit are prepared, the two sets of half-wave rectification circuit and the second power supply unit are connected in parallel, and the currents flowing in the respective circuits The same effect can be obtained even if the phase is shifted by 1/2 period.

DESCRIPTION OF SYMBOLS 1 Load control apparatus 2 Commercial power supply 3 Load 11 Main switching part 12 Rectification part 14 1st power supply part 15 2nd power supply part 16 3rd power supply part 17 Auxiliary switching part 19 Auxiliary power supply part 191 Capacitors 192, 193 Diodes 194, 195, 201 To 204 switch element 196 switching circuit 197 voltage detection circuit 200 DC power supply

Claims (2)

A main opening and closing section for connecting a main electrode of a main switch element in series with a commercial power source and a load, and controlling supply of electric power to the load;
A rectifier connected between the main electrodes of the main switch element;
A control unit that controls on or off of the load according to an external signal;
A first power supply unit for stably supplying power to the control unit;
A second power supply unit that is supplied with power from both ends of the main opening / closing unit via a rectification unit and supplies power to the first power supply unit when the load is turned off;
A third power supply unit that is supplied with power from both ends of the main opening / closing unit via a rectification unit and supplies power to the first power supply unit when the load is turned on;
A load control device comprising an auxiliary opening / closing part connected between output terminals of the rectifying part and conducting before the main opening / closing part when supplying power to the load,
The main switching unit further includes a triac as the main switching element, and further includes an auxiliary power source unit that discharges charges and reduces switching noise when the terminal voltage of the triac decreases.
The auxiliary power unit is
A capacitor charged by the commercial power source;
Two diodes connected between both terminals of the capacitor and both terminals of the commercial power supply for preventing backflow when electric charge is discharged from the capacitor;
The first and second switch elements connected between both terminals of the capacitor and the T1 and T2 terminals of the triac, and the terminal voltage of the triac is changed according to the phase of the commercial power supply. A switching circuit for controlling conduction and non-conduction of the first switch element and the second switch element so as to discharge electric charge from the capacitor so as to complement the terminal voltage of the triac when the voltage drops below the voltage ; A load control device comprising the load control device. A main opening and closing section for connecting a main electrode of a main switch element in series with a commercial power source and a load, and controlling supply of electric power to the load;
A rectifier connected between the main electrodes of the main switch element;
A control unit that controls on or off of the load according to an external signal;
A first power supply unit for stably supplying power to the control unit;
A second power supply unit that is supplied with power from both ends of the main opening / closing unit via a rectification unit and supplies power to the first power supply unit when the load is turned off;
A third power supply unit that is supplied with power from both ends of the main opening / closing unit via a rectification unit and supplies power to the first power supply unit when the load is turned on;
A load control device comprising an auxiliary opening / closing part connected between output terminals of the rectifying part and conducting before the main opening / closing part when supplying power to the load,
The main switching unit further includes a triac as the main switching element, and further includes an auxiliary power source unit that discharges charges and reduces switching noise when the terminal voltage of the triac decreases.
The auxiliary power unit is
DC power supply,
A first switch element and a second switch element connected between the positive side of the DC power source and the T1 terminal and T2 terminal of the triac;
A third switch element and a fourth switch element connected between the negative side of the DC power source and both terminals of the commercial power source;
So as to discharge electric charge from the capacitor to complement the triac terminal voltage, you comprising the switching circuit for controlling conduction and non-conduction of the first switching element to the fourth switching element load control device.

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