TWI654904B - Load control device - Google Patents

Abstract

The present invention provides a load control device capable of responding to more types of loads. Based on the phase detected by the phase detection unit, the control unit divides the half period consisting of the period between two consecutive zero crossings of the AC voltage (Vac) into a first period (T1) and a second period (T2) , The third period (T3), and the fourth period (T4). The control unit makes the two-way switch in a non-conducting state during the first period (T1) and the fourth period (T4), and causes the power supply unit to perform operations. The control unit turns on the bidirectional switch in the second period (T2) to stop the generation operation of the power supply unit. The control unit makes the bidirectional switch in a non-conducting state during the third period (T3), and stops the generation operation of the power supply unit. The changing unit extends the target period composed of at least one of the first period (T1) and the fourth period (T4) when the detection result of the detecting portion does not reach the threshold (Vth1).

Description

Load control device

The present invention generally relates to a load control device, and more specifically, to a load control device that performs phase control on an AC voltage supplied from a load.

In the past, a dimming device for dimming a lighting load is known (for example, Document 1: JP2013-149498A).

The dimming device described in Document 1 includes a pair of terminals, a control circuit section, a switching power supply for supplying control power to the control circuit section, and a dimming operation section for setting a dimming level of a lighting load.

The control circuit unit and the switching power supply are connected in parallel between the pair of terminals, respectively. In addition, a series circuit of an AC power supply and a lighting load is connected between a pair of terminals. The lighting load includes a plurality of LED (Light Emitting Diode) elements, and a power circuit for lighting each LED element. The power supply circuit includes a smoothing circuit of a diode and an electrolytic capacitor.

The control circuit section includes a switch section for phase-controlling the AC voltage supplied to the lighting load; a switch driving section for driving the switch section; and a control section for controlling the switch driving section and the switching power supply.

Switch the power supply in parallel with the switch unit. Switch the power and convert the AC voltage of the AC power to the control power. Switching power supply, equipped with electrolytic capacitors to store control power.

The control unit controls the power supply from the switching power supply through an electrolytic capacitor. The control unit is equipped with a microcomputer. In response to the dimming level set by the dimming operation unit, the microcomputer implements inverse phase control that interrupts the power supply to the lighting load during each half cycle of the AC voltage.

Load control devices such as dimming devices may be electrically connected to various loads such as various lighting loads. Therefore, there is a possibility that the load control device or the load may malfunction due to the load connected to the load control device.

In view of the above-mentioned problems, an object of the present invention is to provide a load control device capable of supporting more types of loads.

One aspect of the present invention is a load control device including a bidirectional switch, a phase detection section, a power supply section, a detection section, a control section, and a change section. For AC power, the bi-directional switch is electrically connected in series with the load and will phase control the AC voltage supplied to the load. The phase detection unit detects a phase of the AC voltage. The power supply unit is provided with a capacitive element that stores electric energy, and is electrically connected in parallel with the bidirectional switch, and generates the electric energy by an electric power supply operation from the AC power source. The detecting unit detects a magnitude of the electric energy stored in the capacitive element. The control section supplies the electric energy from the capacitive element of the power supply section, and controls the bidirectional switch and the power supply section. The control unit is based on the phase detected by the phase detection unit. A half cycle consisting of the period between two consecutive zero crossings of the AC voltage is divided into a first period, a second period, a third period, and a fourth period. The control unit makes the bidirectional switch in a non-conducting state during the first period and the fourth period, and causes the power supply unit to perform the generating operation. The control unit turns on the bidirectional switch in the second period, and stops the generating operation of the power supply unit. The control unit makes the bidirectional switch in a non-conducting state during the third period, and stops the generating operation of the power supply unit. When the change result of the detection unit does not reach the threshold, the changing unit extends the target period formed by at least one of the first period and the fourth period.

1.1A‧‧‧Load control device

2‧‧‧Two-way switch

3‧‧‧Phase detection section

4‧‧‧ Face

5‧‧‧Power Supply Department

6, 6A‧‧‧Control circuit

7‧‧‧ load

8‧‧‧ AC power

9‧‧‧Switch driver

11, 12‧‧‧ input terminals

31‧‧‧The first detection department

32‧‧‧Second Detection Section

51‧‧‧Buck Power

52‧‧‧Switch Power

53‧‧‧Testing Department

61‧‧‧Control Department

62‧‧‧ Change Department

63‧‧‧Stop Department

91‧‧‧1st drive unit

92‧‧‧ 2nd drive unit

511‧‧‧The first circuit

521‧‧‧Second Circuit

C1, C2‧‧‧ Capacitive element

D1, D2, D31, D32‧‧‧ diodes

Q1, Q2‧‧‧ switching elements

Sb1‧‧‧1st control signal

Sb2‧‧‧2nd control signal

Ss1‧‧‧The first power signal

Ss2‧‧‧Second power signal

T0‧‧‧except period

T1‧‧‧First Period

T2‧‧‧Second Period

T3‧‧‧ third period

T4‧‧‧Fourth period

t0, t1, t11, t2, t21, t22, t3, t4

Vac‧‧‧AC voltage

Vc1‧‧‧Drive voltage (DC voltage)

Vc2‧‧‧Control voltage

Vth1, Vth2‧‧‧threshold

Vzc, -Vzc‧‧‧rated value

ZC1‧‧‧1st detection signal

ZC2‧‧‧2nd detection signal

FIG. 1 is a schematic circuit diagram of a load control device according to the first embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of the load control device as described above.

FIG. 3 is a timing chart showing the operation of the case where the electric energy stored in the capacitive element in the load control device is insufficient.

4 is a timing chart showing the operation of the load control device according to the first modification of the first embodiment of the present invention.

Fig. 5 is a schematic circuit diagram of a load control device according to a second embodiment of the present invention.

FIG. 6 is a timing chart showing the operation of the load control device as described above.

FIG. 7 is a timing chart showing the operation of the case where the electric energy stored in the capacitive element in the load control device is insufficient as described above.

8 is a timing chart showing the operation of a load control device according to a modification of the second embodiment of the present invention.

The structure described below is only an example of the present invention, and the present invention is not limited to the following embodiments. Even outside of this embodiment, various changes can be made in accordance with the design and the like without departing from the scope of the technical idea of the invention .

(Embodiment 1)

(1) Summary

As shown in FIG. 1, the load control device 1 of this embodiment includes a bidirectional switch 2, and for an AC power source 8, the bidirectional switch 2 is electrically connected in series with a load 7. The load control device 1 controls the phase of the AC voltage Vac supplied from the AC power source 8 to the load 7 through the bidirectional switch 2. The “phase control” mentioned here refers to controlling the supply (application) of the load 7 to the load 7 by changing the phase angle (conduction angle) at which the load 7 is energized at the beginning or end of each half cycle of the AC voltage Vac. Way of AC voltage Vac. That is, the load control device 1 controls the load 7 such as a lighting load, a heater, or a fan by phase-controlling the AC voltage Vac supplied to the load 7.

In this embodiment, as an example, a case where the load 7 is an illumination load including a plurality of LED elements and a power supply circuit that lights up the plurality of LED elements will be described. That is, the load control device 1 constitutes a dimming device that adjusts the amount of light emitted by the load 7 constituted by the lighting load by phase control. The AC power source 8 is, for example, a single-phase commercial power source of 100 [V] and 60 [Hz]. The load control device 1 can be applied to, for example, a wall switch or the like.

Here, the load control device 1 of the present embodiment is a two-wire type, and the bidirectional switch 2 is electrically connected in series with the load 7 to the AC power source 8 and is electrically connected between the AC power source 8 and the load 7. In other words, the electric wire connected to the AC power source 8 and the electric wire connected to the load 7 are connected to the load control device 1, and a two-way switch 2 is inserted between the two electric wires. Therefore, if the bidirectional switch 2 is in the on state, then A voltage from the AC power source 8 is applied to the load 7 to supply power to the load 7; if the bidirectional switch 2 is in a non-conducting state, a voltage from the AC power source 8 is applied to the load control device 1 and the power supply to the load 7 is stopped. The load control device 1 obtains the operation power of the load control device 1 itself from the AC power source 8 through these two wires, and controls the two-way switch 2 and the like. That is, when the bidirectional switch 2 is in a non-conducting state, the power supply unit 5 described later generates its own operating power, so that the two-wire load control device 1 can be realized.

(2) Composition

As shown in FIG. 1, the load control device 1 of this embodiment includes a pair of input terminals 11 and 12, a bidirectional switch 2, a phase detection section 3, an interface section 4, a power supply section 5, a control circuit 6, a switch driving section 9, The detection unit 53 and the diodes D1 and D2. The control circuit 6 includes a control unit 61 and a changing unit 62. The "input terminal" described herein may not be a component (terminal) for connection with a wire or the like, and may be, for example, a lead of an electronic component or a part of a conductor included in a circuit board.

The bidirectional switch 2 is composed of, for example, two elements, a first switching element Q1 and a second switching element Q2 electrically connected in series between the input terminals 11 and 12. For example, the switching elements Q1 and Q2 are semiconductor switching elements each composed of an enhanced n-channel MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

The switching elements Q1 and Q2 are connected between the input terminals 11 and 12 in a so-called reverse series connection. That is, the switching elements Q1 and Q2 connect the sources to each other. The drain of the switching element Q1 is connected to the input terminal 11, and the drain of the switching element Q2 is connected to the input terminal 12. Sources of the two switching elements Q1 and Q2 are connected to a ground portion of the power supply unit 5. The ground portion of the power supply unit 5 is a reference potential for the internal circuit of the load control device 1.

The bidirectional switch 2 can switch four states by a combination of ON (on) and OFF (off) of the switching elements Q1 and Q2. 4 states, including: bidirectional OFF state, both switching elements Q1, Q2 are OFF; bidirectional ON state, both switching elements Q1, Q2 are ON; and 2 unidirectional ON states, only one of switching elements Q1, Q2 Is ON. In the one-way ON state, a pair of input terminals 11 and 12 are turned on in a single direction from a switching element of one of the switching elements Q1 and Q2 via a parasitic diode of the switching element of the OFF one. For example, the switching element Q1 is turned on and the switching element Q2 is turned off, and a first unidirectional ON state in which a current flows from the input terminal 11 to the input terminal 12 is established. In addition, the switching element Q2 is ON, and the switching element Q1 is OFF, and is in a second unidirectional ON state where current flows from the input terminal 12 to the input terminal 11. Therefore, when an AC voltage Vac is applied from the AC power source 8 to the input terminals 11 and 12, during the half cycle of the positive polarity of the AC voltage Vac, that is, the input terminal 11 is on the high potential side and the input terminal 12 is on the half of the low potential side During the cycle, the first unidirectional ON state becomes the "forward ON state" and the second unidirectional ON state becomes the "reverse ON state". On the other hand, during the half cycle of the negative polarity of the AC voltage Vac, that is, the half cycle of the input terminal 11 on the low potential side and the input terminal 12 on the high potential side, the second unidirectional ON state becomes the "forward ON state" , The first one-way ON state becomes the "reverse ON state".

Here, the two states of the two-way switch 2 are a “two-way ON state” and a “forward ON state”, which are both conductive states, and the two states of the “two-way OFF state” and “reverse ON state” are non-conductive states.

The phase detection unit 3 detects the phase of the AC voltage Vac applied between the input terminals 11 and 12. The “phase” described here includes the zero-crossing point of the AC voltage Vac and the polarity (positive polarity, negative polarity) of the AC voltage Vac. The phase detection unit 3 is configured to output a detection signal to the control circuit 6 when a zero crossing point of the AC voltage Vac is detected. The phase detection section 3 includes a diode D31, a first detection section 31, a diode D32, and a second detection section 32. The first detection unit 31 is electrically connected to the input terminal 11 via the diode D31. connection. The second detection unit 32 is electrically connected to the input terminal 12 via a diode D32. The first detection unit 31 detects a zero crossing point when the AC voltage Vac changes from a half cycle of a negative polarity to a half cycle of a positive polarity. The second detection unit 32 detects a zero crossing point when the AC voltage Vac changes from a half cycle of the positive polarity to a half cycle of the negative polarity.

That is, if the first detection unit 31 detects that the voltage from the input terminal 11 is on the high potential side and the input terminal 12 is on the low potential side, the state that has never reached a predetermined value is changed to a state of a predetermined value or more, it is determined as At the zero crossing point, the first detection signal ZC1 is output to the control circuit 6. Similarly, if the second detection unit 32 detects that the voltage at the input terminal 11 is on the low potential side and the input terminal 12 is on the high potential side, the state that has never reached a predetermined value is changed to a state above the predetermined value, it is determined as At the zero crossing point, the second detection signal ZC2 is output to the control circuit 6. The predetermined value is a value (absolute value) set near 0 [V]. For example, the predetermined value of the first detection unit 31 is approximately [V], and the predetermined value of the second detection unit 32 is approximately [V]. Therefore, the detection point of the zero-crossing point detected by the first detection section 31 and the second detection section 32 is delayed from the zero-crossing point (0 [V]) under a strict definition by a little time.

For the interface portion 4, an input level of a phase angle (conduction angle) that starts or ends the energization of the load 7 with respect to each half cycle of the AC voltage Vac is input. That is, the input level specifies a time point at which the bidirectional switch 2 is turned on or a time point when it is turned off during a half cycle of the AC voltage Vac. In this embodiment, the load control device 1 is a dimming device, so the interface portion 4 accepts operations performed by the user, and accepts input as a dimming level of the input level. The interface portion 4 outputs a dimming signal indicating the dimming level to the control circuit 6. The dimming signal is a numerical value that specifies the amount of light output of the load 7, and may include the "OFF level" that causes the load 7 to be turned off. In this embodiment, as an example, the mesial portion 4 includes a touch panel that accepts a touch operation by a user. Interface part 4, indicating input level for output (dimming level) The signal may be constituted by, for example, a variable resistor or a rotary switch. Furthermore, the interface part may be constituted by a receiving section that receives signals from a communication terminal such as a remote controller or a smart phone.

In addition, in the present embodiment, the mesial portion 4 further includes a display section (instruction section) that displays the input level (dimming level) of the input. The interface portion 4 includes, for example, a display portion composed of a plurality of LED elements, and displays the input level by the number of lights of the LED elements.

The control circuit 6 has a function as a control section 61 and a changing section 62. The control unit 61 controls the bidirectional switch 2 based on a detection signal from the phase detection unit 3 and a dimming signal from the interface portion 4. The control unit 61 controls the switching elements Q1 and Q2 individually. Specifically, the control unit 61 controls the switching element Q1 with a first control signal Sb1 and controls the switching element Q2 with a second control signal Sb2. The changing unit 62 changes the length of a period during which the power supply unit 5 performs the operation (the first period T1 and the fourth period T4 described later). The change section 62 will be explained in detail in the field "(3.3) Operation of the power supply section".

The control circuit 6 includes, for example, a microcomputer as a main configuration. The microcomputer realizes the function as the control circuit 6 by executing a program recorded in the memory of the microcomputer by a CPU (Central Processing Unit, central memory). The program can be recorded in the memory of the microcomputer in advance, or provided in a recording medium such as a memory card, or provided through an electrical communication line. In other words, the above program is a program for causing a computer (here, a microcomputer) to function as the control circuit 6.

The switch driving unit 9 includes a first driving unit 91 that drives (ON / OFF control) the switching element Q1 and a second driving unit 92 that drives (ON / OFF control) the switching element Q2. The first driving unit 91 receives the first control signal Sb1 from the control circuit 6 and applies a gate voltage to the switching element Q1. Thereby, the first driving unit 91 performs ON / OFF control of the switching element Q1. Similarly, the second driving unit 92 receives a second control signal from the control circuit 6 Sb2, a gate voltage is applied to the switching element Q2. Thereby, the second driving unit 92 performs ON / OFF control of the switching element Q2. The first driving unit 91 generates a gate voltage based on the potential of the source of the switching element Q1. The second driving unit 92 is also the same.

The power source unit 5 includes a step-down power source 51 that generates driving power (electric energy) for operating the switch driving unit 9 and the like, and switches the power source 52 to generate control power. The driving power is power for operating the switch driving unit 9 and the like. The control power is power for operating the interface portion 4 and the control circuit 6 and the like. The power supply unit 5 executes a power generation operation (driving power) by the step-down power supply 51 by supplying power from the AC power supply 8. By switching the power supply 52, the electric power (driving power) generated by the step-down power supply 51 is converted into control power.

The power supply unit 5 is electrically connected to the input terminal 11 via the diode D1, and is electrically connected to the input terminal 12 via the diode D2. With this, the diode bridge composed of the diodes D1 and D2 and the respective parasitic diodes of the switching elements Q1 and Q2 rectifies the full-wave AC voltage Vac applied between the input terminals 11 and 12, Then, it is supplied to the power supply unit 5. Therefore, when the bidirectional switch 2 is in a non-conducting state, a full-wave rectified AC voltage Vac (pulse current voltage output from a diode bridge) is applied to the power source section 5.

The step-down power supply 51 includes a first circuit 511 and a capacitive element (capacitor) C1. The step-down power supply 51 is a series regulator-type power supply circuit. By applying the full-wave rectified AC voltage Vac, the applied voltage is stepped down and smoothed to generate a DC driving voltage Vc1. That is, when the full-wave rectified AC voltage Vac is applied to the first circuit 511, the capacitive element C1 is charged, and a driving voltage Vc1 is generated across the capacitive element C1. The step-down power supply 51 supplies the electric energy stored in the capacitive element C1 to the switch driving section 9 and the switching power supply 52 as driving power. The driving voltage Vc1 is, for example, 15 [V].

The switching power supply 52 includes a second circuit 521 and a capacitive element (capacitor) C2. The switching power supply 52 is a DC-DC converter with a switching method such as a step-down chopper circuit. The driving voltage Vc1 is applied from the step-down power supply 51, and the applied DC voltage (driving voltage Vc1) is reduced to generate a direct current. Control voltage Vc2. That is, when the driving voltage Vc1 is applied to the second circuit 521, the capacitive element C2 is charged, and a control voltage Vc2 is generated across the capacitive element C2. The second circuit 521 includes a switching element (semiconductor switch), and the driving voltage Vc1 is stepped down by the switching of the switching element to generate a control voltage Vc2. In short, the switching power supply 52 performs a switching operation, and the DC voltage supplied from the capacitive element C1 is converted into the control voltage Vc2 by the switching operation of the switching element. The control power generated by the switching operation of the switching power supply 52 is supplied to the interface portion 4 and the control circuit 6 and the like. The control voltage Vc2 is, for example, 3.5 [V].

Therefore, in the switching operation of the switching power supply 52, the control circuit 6 (the control section 61) is supplied with power from the capacitive element C1 of the power supply section 5 via the switching power supply 52. The control circuit 6 (control unit 61) is operated by electric energy (control power) from the power supply unit 5.

The step-down power supply 51 and the switching power supply 52 are configured to be controllable by the control unit 61. In other words, the control section 61 has a function of controlling the power supply section 5. Thereby, the control section 61 controls whether or not the power supply section 5 performs a generation operation of generating electric energy (driving power) stored in the capacitive element C1. Further, the control unit 61 controls whether or not the power supply unit 5 performs a conversion operation for generating electric energy (control power) stored in the capacitive element C2.

In this embodiment, the control unit 61 controls the semiconductor switches included in the step-down power supply 51 to switch the state in which the power supply unit 5 performs the generation operation and the state in which the generation operation of the power supply unit 5 is stopped. Specifically, the control unit 61 controls the semiconductor switch of the step-down power supply 51 with the first power signal Ss1. The control unit 61 increases the input impedance of the step-down power supply 51 by stopping the operation of the first circuit 511, and stops the step-down power supply 51. The production operation. Once the generation operation of the step-down power source 51 is stopped by the first power signal Ss1, the generation of electric energy (driving power) by the power source unit 5 is stopped. Further, the control section 61 controls a switching element included in the switching power supply 52 to switch a state where the power supply section 5 performs a switching operation and a state where the switching operation of the power supply section 5 is stopped. Specifically, the control unit 61 controls the switching element that switches the power supply 52 with the second power signal Ss2. When the switching operation of the switching power supply 52 is stopped, the generation of electric energy (control power) by the power supply section 5 is stopped.

The detecting unit 53 detects the magnitude of the electric energy stored in the capacitive element C1. In this embodiment, the detection unit 53 is configured to detect the magnitude of the driving voltage Vc1 of the voltage across the capacitive element C1. The detection unit 53 is, for example, a voltage-dividing resistor connected between both ends of the capacitive element C1, and outputs a voltage corresponding to the driving voltage Vc1 to the control circuit 6 as a detection value. That is, the detection unit 53 directly detects the magnitude of the electric energy stored in the capacitive element C1 by detecting the voltage (driving voltage Vc1) across the capacitive element C1. In the following, the detection value of the detection unit 53 is made equal to the driving voltage Vc1. However, the configuration is not limited to such a configuration. For example, the detection unit 53 may be configured to indirectly detect the magnitude of the electric energy stored in the capacitive element C1 by detecting the control voltage Vc2 of the voltage across the capacitive element C2. .

The lighting circuit of the load 7 reads the dimming level from the waveform of the phase-controlled AC voltage Vac in the load control device 1 to change the amount of light emitted by the LED element. Here, as an example, the lighting circuit includes a circuit for securing a current such as a bleeder circuit. Therefore, during a period in which the bidirectional switch 2 of the load control device 1 is non-conductive, a current can still flow through the load 7.

(3) Operation

(3.1) Start operation

First, the start-up operation of the load control device 1 according to the present embodiment at the start of energization will be described.

According to the load control device 1 configured as described above, if an AC power source 8 is connected between the input terminals 11 and 12 via the load 7, the AC voltage Vac applied from the AC power source 8 to the input terminals 11 and 12 is rectified to a step-down power source. 51Supply. The driving power generated in the step-down power supply 51 is supplied to the switch driving section 9 and is supplied to the switching power supply 52. When the control power generated by the switching power supply 52 is supplied to the control circuit 6 and the interface portion 4, the control circuit 6 and the interface portion 4 are activated.

When the control circuit 6 is activated, the control circuit 6 determines the frequency of the AC power source 8 based on the detection signal from the phase detection unit 3. Then, the control circuit 6 refers to the numerical table stored in the memory in advance in accordance with the determined frequency, and performs setting of various parameters such as time. Here, if the dimming level input to the interface portion 4 is the "OFF level", the control circuit 6 maintains the bidirectional switch 2 in the bidirectional OFF state, and impedance between the pair of input terminals 11 and 12 Maintained in a high impedance state. Thereby, the load 7 is maintained in the light-off state.

(3.2) Load control operation

Next, a load control operation of the load control device 1 according to this embodiment will be described with reference to FIG. 2. In Figure 2, the AC voltage "Vac", the first detection signal "ZC1", the second detection signal "ZC2", the first control signal "Sb1", the second control signal "Sb2", and the first power signal "Ss1" are displayed. And the driving voltage "Vc1".

In this embodiment, the first detection signal ZC1 is changed from the “H” level (High Level) to the “L” level (Low Level), which is regarded as the first detection signal ZC1 generated. In addition, changing the second detection signal ZC2 from the "H" level to the "L" level is regarded as the generation of the second detection signal ZC2. that is, The first detection signal ZC1 and the second detection signal ZC2 are signals that change from the "H" level to the "L" level when the phase (zero crossing point) is detected by the phase detection unit 3. The first power supply signal Ss1 and the driving voltage Vc1 will be described in the field of "(3.3) Controlling Power Generation and Operation".

The control section 61 divides the half period of the AC voltage Vac into a first period T1, a second period T2, a third period T3, and a fourth period T4 based on the phase detected by the phase detection section 3, and controls the bidirectional switch 2 . The "half period" mentioned here refers to a period between two consecutive zero crossings of the AC voltage Vac. In the first period T1 and the fourth period T4, the control unit 61 makes the two-way switch 2 in a non-conductive state. In the second period T2, the control unit 61 turns the bidirectional switch 2 into an ON state. In the third period T3, the control unit 61 makes the two-way switch 2 non-conductive.

Hereinafter, operations of the load control device 1 in the first period T1, the second period T2, the third period T3, and the fourth period T4 are described in further detail.

First, the operation of the load control device 1 in a half cycle in which the AC voltage Vac has a positive polarity will be described. The load control device 1 detects a zero crossing point of the AC voltage Vac, which is a reference for phase control, by the phase detection unit 3. When the AC voltage Vac changes from the half cycle of the negative polarity to the half cycle of the positive polarity, if the AC voltage Vac reaches the predetermined value "Vzc" of the positive polarity, the first detection section 31 outputs a first detection signal ZC1. The control unit 61 sets the first time point t1 after the time point t11 at which the first detection signal ZC1 is generated, that is, after the detection time point of the phase (zero crossing point) of the phase detection unit 3, at the first time point t1 In the middle, the first control signal Sb1 and the second control signal Sb2 are set to "ON" signals. In the example in FIG. 2, the detection time point (time point t11) in the phase detection section 3 coincides with the first time point t1. In other words, in the example of FIG. 2, at the first time point t1, the phase detection unit 3 detects the phase, and the control unit 61 causes the bidirectional switch 2 to be turned on in both directions. The period from the start point (zero crossing point) t0 of the half cycle of the positive polarity to the first time point t1 becomes the first Period T1. In the first period T1, the control unit 61 sets the first control signal Sb1 and the second control signal Sb2 to "OFF" signals. Thereby, in the first period T1, both the switching elements Q1 and Q2 are turned OFF, and the bidirectional switch 2 is turned into a bidirectional OFF state (non-conductive state). Therefore, in the first period T1, the power supply from the AC power source 8 to the load 7 is cut off.

The second time point t2 is a time point from the detection time point (time point t11) of the phase (zero crossing point) of the phase detection section 3 to the ON time corresponding to the length of the dimming signal. At the second time point t2, the control unit 61 maintains the second control signal Sb2 as the "ON" signal and makes the first control signal Sb1 as the "OFF" signal. Therefore, in the second period T2 from the first time point t1 to the second time point t2, the switching elements Q1 and Q2 are both turned ON, and the bidirectional switch 2 is turned into a bidirectional ON state (on state). Therefore, in the second period T2, power is supplied from the AC power source 8 to the load 7 via the bidirectional switch 2.

The third time point t3 is a time point earlier than the end point (zero crossing point) t4 of the half cycle by a certain time (for example, 300 [μs]). That is, the third time point t3 is estimated to be the end point t4 at the time point (time point t11) from the detection time point of the zero crossing point of the phase detection unit 3, which is the time at which the time of the first period T1 is subtracted from the time of the half cycle. In this case, it is a time point earlier than this end point t4 for a certain length of time. The time point diagram in FIG. 2 illustrates the third time point t3 as the time point when the AC voltage Vac reaches the predetermined value “Vzc” of the positive polarity and the time point when the AC voltage Vac reaches the predetermined value “−Vzc” of the negative polarity. . However, in fact, the determination of the third time point t3 has nothing to do with the time point when the AC voltage Vac crosses the predetermined value “Vzc” of the positive polarity or the predetermined value “-Vzc” of the negative polarity.

At the third time point t3, the control circuit 6 causes the first control signal Sb1 and the second control signal Sb2 to be "OFF" signals. Thereby, in the third period T3 from the second time point t2 to the third time point t3, the switch is turned on. Among the off elements Q1 and Q2, only the switching element Q1 is OFF, and the bidirectional switch 2 is turned on in the reverse direction (non-conductive state). Therefore, in the third period T3, the power supply from the AC power source 8 to the load 7 is cut off.

During the fourth period T4 from the third time point t3 to the end of the half cycle (zero crossing point) t4, the switching elements Q1 and Q2 are both turned OFF, and the bidirectional switch 2 is turned into a bidirectional OFF state (non-conductive state).

In addition, the operation of the load control device 1 in the half cycle in which the AC voltage Vac is of the negative polarity is basically the same as that of the half cycle of the positive polarity.

In the half cycle of the negative polarity, once the AC voltage Vac reaches the predetermined value “-Vzc” of the negative polarity, the second detection unit 32 outputs a second detection signal ZC2. In this embodiment, from the start point t0 (t4) of the half cycle of the negative polarity to the time set after the generation time of the second detection signal ZC2, that is, the detection time point of the phase (zero crossing point) set in the phase detection section 3 (Time point t11) The period until the first time point t1 after that becomes the first period T1. In addition, the second time point t2 is the time point when the ON time corresponding to the length of the dimming signal passes from the detection time point (time point t11) of the phase (zero crossing point) of the phase detection section 3; the third time point t3 is, It is a certain time (for example, 300 [μs]) minutes earlier than the end point t4 (t0) of the half cycle.

In the first period T1, the control unit 61 sets the first control signal Sb1 and the second control signal Sb2 to "OFF" signals. Thereby, in the first period T1, the bidirectional switch 2 is turned into a bidirectional OFF state (non-conductive state). Then, at the first time point t1, the control unit 61 sets the first control signal Sb1 and the second control signal Sb2 to "ON" signals. Therefore, in the second period T2 from the first time point t1 to the second time point t2, the switching elements Q1 and Q2 are both turned ON, and the bidirectional switch 2 is turned into a bidirectional ON state (on state). Therefore, in the second period T2, power is supplied from the AC power source 8 to the load 7 via the bidirectional switch 2.

At the second time point t2, the control unit 61 maintains the first control signal Sb1 as the "ON" signal and makes the second control signal Sb2 as the "OFF" signal. At the third time point t3, the control unit 61 sets the first control signal Sb1 and the second control signal Sb2 to "OFF" signals. Accordingly, in the third period T3 from the second time point t2 to the third time point t3, only the switching element Q2 among the switching elements Q1 and Q2 is turned OFF, and the bidirectional switch 2 is turned into the reverse ON state (non-conducting state). ). Therefore, in the third period T3, the power supply from the AC power source 8 to the load 7 is cut off. In the fourth period T4 from the third time point t3 to the end point t4 of the half cycle, the switching elements Q1 and Q2 are both OFF, and the bidirectional switch 2 is in a bidirectional OFF state (non-conductive state).

The load control device 1 of this embodiment performs dimming of the load 7 by alternately repeating the above-mentioned half-cycle operation of the positive polarity and the half-cycle operation of the negative polarity at each half cycle of the AC voltage Vac. Here, the "bidirectional ON state" is a conducting state and the "reverse ON state" is a non-conducting state. Therefore, at the end of the second period, that is, the second time point t2, the bidirectional switch 2 is switched from the conducting state to the non-conducting state. The end point of the second period (second time point t2) is defined by the dimming level input to the interface portion 4. Further, if the predetermined value "Vzc" of the positive polarity and the predetermined value "-Vzc" of the negative polarity are fixed values, the detection time (time point) of the phase (zero crossing point) of the phase detection section 3 from the starting point t0 of the half cycle The time up to t11) is a slightly fixed time.

Therefore, the time from the start point t0 of the half cycle to the second time point t2 is the "variable time" of the total time of the first period T1 and the second period T2 whose length is changed according to the dimming level. Dimming the level to change the length. In other words, the phase angle (conduction angle) at the second time point t2 at which the energization of the AC voltage Vac to the load 7 is completed in each half cycle is changed in accordance with the dimming level. That is, when the amount of light output from the load 7 is reduced, the variable time is specified as a short time (the phase angle is small), and when the amount of light output from the load 7 is increased, the variable time is specified as a long time (the phase angle) Big). Therefore, the load control device 1 can change the amount of light output from the load 7 according to the dimming level input to the interface portion 4.

In addition, in the half period of the AC voltage Vac, the period (the first period T1, the third period T3, and the fourth period T4) other than the period (second period T2) from the first time point t1 to the second time point t2. ), The bidirectional switch 2 is turned off (reverse ON state or bidirectional OFF state). The load control device 1 can ensure the power supply from the AC power source 8 to the power source unit 5 while the bidirectional switch 2 is in a non-conducting state. The operation of the power supply unit 5 will be explained in detail in the field of "(3.3) Operation of the power supply unit".

The expression "from time point A" here means the meaning of including time point A. For example, "from the first point in time" means the meaning including the first point in time. On the other hand, the expression "until time point A" means the meaning immediately before time point A without including time point A. For example, "up to the end of the half cycle" means the end point that does not include the half cycle and immediately before the end of the half cycle.

(3.3) Operation of power supply department

Next, the operation of the power supply unit 5 will be described with reference to FIG. 2.

The control section 61 divides the half period of the AC voltage Vac into a first period T1, a second period T2, a third period T3, and a fourth period T4 based on the phase detected by the phase detection section 3, and controls the power supply section 5 . In the first period T1 and the fourth period T4, the control unit 61 causes the power supply unit 5 to perform a production operation. In the second period T2, the control unit 61 stops the generation operation of the power supply unit 5. In the third period T3, the control unit 61 stops the generation operation of the power supply unit 5. In other words, the power supply unit 5 performs generation operation of generating electric energy (driving power) by supplying power from the AC power source 8 in only the first period T1 and the fourth period T4 of the half cycle of the AC voltage Vac.

Specifically, the control unit 61 sets the first power signal Ss1 to an "ON" signal (for example, H level) in only the first period T1 and the fourth period T4 in the half cycle of the AC voltage Vac, and The power supply unit 5 is operated. The control unit 61 stops the generation operation of the power supply unit 5 by setting the first power signal Ss1 to an "OFF" signal (for example, L level) in the second period T2 and the third period T3. In short, the power supply unit 5 performs the power generation (driving power) generation operation with the step-down power supply 51 between the first power signal Ss1 being the "ON" signal. At this time, the switching power supply 52 of the power supply unit 5 performs a switching operation. On the other hand, the power supply unit 5 stops generating the electric energy (driving power) in the step-down power supply 51 between the first power signal Ss1 being the "OFF" signal and stops the generating operation. Switching the power supply 52 does not stop the conversion operation as soon as the first power signal Ss1 becomes the "OFF" signal, but continues the conversion operation by the charge stored in the capacitive element C1 between the first power signal Ss1 and the "ON" signal . That is, if sufficient electric energy (driving power) is stored in the capacitive element C1, the load control device 1 can continue to operate even when the generation of electric energy (driving power) of the step-down power supply 51 is stopped.

However, in the load control device 1, when the first power signal Ss1 is changed from the "OFF" signal to the "ON" signal, it is not necessary to coincide with the third time when the first control signal Sb1 and the second control signal Sb2 become "OFF" signals. Point t3 agrees. For example, the first power signal Ss1 may be turned "ON" at a point earlier than the third time point t3, that is, at any time point between the second time point t2 and the third time point t3. In this case, the time point when the first power signal Ss1 changes from the "OFF" signal to the "ON" signal becomes the boundary point between the third period T3 and the fourth period T4. That is, the bidirectional switch 2 is in a non-conducting state before and after the third time point t3, so it can also be started by making the first power signal Ss1 an "ON" signal at a time earlier than the third time point t3. Fourth period T4.

By operating the power supply unit 5 as described above, the driving voltage Vc1 rises during the first period T1 and the fourth period T4 in the half cycle of the AC voltage Vac, and the driving voltage increases during the second period T2 and the third period T3 Vc1 drops. Therefore, if focusing on two consecutive half cycles, the driving voltage Vc1 rises from the third time point t3 of the first half cycle to the first time point t1 of the next half cycle (ie, the second half cycle). .

According to the load 7, during the first period T1 and the fourth period T4, the power supply unit 5 cannot receive sufficient power supply from the AC power source 8, the electric energy stored in the capacitive element C1 is insufficient, and the load control device 1 cannot be maintained. Normal operation. That is, depending on the load 7, the power (driving power) generated by the step-down power supply 51 during the half cycle of the AC voltage Vac may be lower than the power consumed by the load control device 1 during the half cycle of the AC voltage Vac. In these cases, the electric energy stored in the capacitive element C1 of the step-down power supply 51 is gradually decreased during each half cycle of the AC voltage Vac. If these states continue, there is a possibility that the electric energy stored in the capacitive element C1 is insufficient and the normal operation of the load control device 1 cannot be maintained. When the driving voltage Vc1 decreases to some extent due to the decrease in the electric energy stored in the capacitive element C1, for example, the generation of control power using the switching power supply 52 of the driving power becomes unstable, and the operation of the interface portion 4 becomes unstable. And so on. As a result, for example, the flashing or flickering of the display portion of the interface portion 4 or the flashing or flickering of the load 7 may occur, and the load control device 1 or the load 7 may malfunction.

As shown in FIG. 3, the load control device 1 according to this embodiment is configured so that the length of a target period including at least one of the first period T1 and the fourth period T4 is determined by the detection result of the detection unit 53. The changing unit 62 changes. FIG. 3 is a timing chart similar to FIG. 2 when the electric energy stored in the capacitive element C1 is insufficient due to the load 7. In this embodiment, as an example, the first period T1 is set as a target period. That is, the length of the period (the first period T1 and the fourth period T4) during which the control unit 61 causes the power supply unit 5 to operate is not constant, but changes according to the detection result of the detection unit 53.

When the detection result of the detection unit 53 does not reach the predetermined threshold value Vth1 (see FIG. 3), the changing unit 62 extends the target period (the first period T1 in the present embodiment). Specifically, the changing unit 62 compares The detection result (driving voltage Vc1) of the detection unit 53 and the threshold value Vth1. If the detection result of the detection unit 53 is equal to or greater than the threshold Vth1, the changing unit 62 uses a preset value as the length of the target period. On the other hand, if the detection result of the detection unit 53 does not reach the threshold value Vth1, the changing unit 62 extends the target period by a certain time ΔT (refer to FIG. 3). The threshold value Vth1 can ensure the operation of the load control device 1 to at least a half cycle of the AC voltage Vac, so that it is the voltage across the capacitive element C1 (the driving voltage Vc1) when the capacitive element C1 is charged. Specifically, regardless of the dimming level, the value of the minimum value plus a predetermined margin is used as the threshold value Vth1 so that the driving voltage Vc1 is not lower than a predetermined minimum value. In FIG. 3, an imaginary line (two-point chain line) shows a situation in which the electric energy stored in the capacitive element C1 is insufficient, that is, the driving voltage Vc1 has the same waveform as the driving voltage Vc1 shown in FIG. 2.

Here, the detection unit 53 continuously detects the magnitude of the electric energy (the magnitude of the driving voltage Vc1) stored in the capacitive element C1 during the operation of the load control device 1. Then, the change unit 62 extends the target period from the first target period after the end of the detection period when the detection result of the detection portion 53 is lower than the threshold value Vth1 during the detection period. The detection period described here is a period in which the detection result of the detection unit 53 is lower than the threshold value Vth1, and the detection unit 53 performs continuous detection. The first period T1, the second period T2, the third period T3, and the third period Any of the four periods T4. For example, as shown in FIG. 3, in the fourth period T4 of the second half period in the figure, when the detection result of the detection unit 53 is lower than the threshold value Vth1, the fourth period T4 of the second half period is detected period. From the first target period after the end of this detection period (the fourth period T4 of the second half period), that is, from the first period T1 of the third half period, the changing unit 62 changes the target period (the first period The period T1) is extended for a certain time ΔT minutes.

In this embodiment, once the target period is extended, the change unit 62 continues to apply the extended target period until the load control device 1 is turned off (the load 7 is turned off). Therefore, the first period T1 after the third half period in FIG. 3 is set to a length in which a predetermined time ΔT is added to the preset value. In this case, the control unit 61 sets the first time point t1 at a generation time point of the first detection signal ZC1, that is, a certain time at the time point t11 which is the detection time point of the phase (zero crossing point) of the phase detection unit 3. Time point after ΔT. Then, at the first time point t1, the control unit 61 sets the first control signal Sb1 and the second control signal Sb2 to "ON" signals, and sets the first power signal Ss1 to "OFF" signals. That is, the first time point t1 of the end point of the first period T1 (or the start point of the second period T2) is delayed by a certain time ΔT minutes from the detection time point of the phase (zero crossing point) of the phase detection unit 3. Thereafter, when the load control device 1 is turned OFF (the load 7 is turned off), the length of the target period (the first period T1) is reset to a preset value.

In this way, when the electric energy stored in the capacitive element C1 is insufficient, the detection section 53 detects a decrease in electric energy, and the change section 62 causes the power supply section 5 to perform a target period for generating and operating electric energy (first period T1) extend. Therefore, the electric energy (driving power) generated in the power supply unit 5 during the target period is increased by the length of the target period, and as a result, the shortage of the electric energy stored in the capacitive element C1 is suppressed.

In the case of this embodiment, the AC voltage Vac is divided into half cycles in order to prioritize the power supply from the AC power source 8 to the power supply unit 5. Therefore, the second period T2 is not defined in accordance with the dimming level input to the interface portion 4. The length of the case. For example, even if the user operates the interface portion 4 to maximize the light output of the load 7, the extension of the first period T1 is given priority, and the starting point of the second period T2 is not set according to the dimming signal from the interface portion 4. situation.

The control method of the load control device 1 has a leading edge control method in addition to a trailing edge control method and a leading edge control method, and reaches zero crossing on the way of the half cycle of the AC voltage Vac. During the period up to that point, the pair of input terminals 11 and 12 are conducted. Reverse phase control method, starting from the zero crossing point, power is supplied to the load 7 with the LED element as a light source, so the The distortion of the current waveform at the start of the power supply is suppressed to be small. This has the advantages of increasing the number (number of lamps) of loads 7 that can be connected to the load control device 1 and suppressing the generation of vibration noise.

The load control device 1 of this embodiment basically adopts an inverse phase control method, and starts supplying power to the load 7 at a first time point t1 which is slightly delayed from the start point (zero crossing point) t0 of the half cycle. Therefore, compared with the inverse-phase control method in which the power supply to the load 7 is started at the zero crossing point, there is a possibility that the current waveform distortion becomes larger. However, since the absolute value of the AC voltage Vac at the first time point t1 is not very large, the influence of the current waveform distortion is a small influence that can be ignored.

Further, the load control device 1 of this embodiment makes the bidirectional switch 2 in the reverse ON state during the period from the second time point t2 to the third time point t3 (third period T3), so that phase detection can be reduced. Mistake detection by Department 3. That is, depending on the load 7, the absolute value of the voltage across the load 7 exceeds the absolute value of the AC voltage Vac. As a result, a voltage with a reverse polarity to the AC voltage Vac is applied to a pair of input terminals 11, 12 (hereinafter referred to as "inverse Polarity voltage "). For example, in the case where a load 7 having a large-capacity snubber capacitor, such as a load 7, is not easily dropped at both ends, it is easy to generate such reverse polarity voltages. When the reverse-polarity voltage is generated, the phase detection unit 3 may erroneously detect the zero-cross point other than the zero-cross point of the AC voltage Vac. There is also a load 7 which is generated due to the dimming level and does not generate a reverse polarity voltage. In these loads 7, if the dimming level is changed, the zero crossing point is suddenly changed. In the third period T3, by causing the bidirectional switch 2 to be in the reverse ON state, the generation of these reverse polarity voltages is suppressed, so that erroneous detection by the phase detection unit 3 due to the reverse polarity voltage can be reduced.

(4) Modifications

(4.1) Modification 1

As shown in FIG. 4, the load control device 1 according to the first modification of the first embodiment. The change unit 62 extends the target period to the detection result when the detection result of the detection unit 53 does not reach the first threshold value Vth1 as the threshold value described above. Until the second threshold Vth2 is reached. That is, in the first modification of the first embodiment, the extension time of the target period generated by the changing unit 62 is not a fixed length (a certain time ΔT), but a variable-length time determined according to the detection result of the detection unit 53. . Hereinafter, the same reference numerals are given to the same configurations as those of the embodiment, and descriptions thereof are appropriately omitted. In FIG. 4, an imaginary line (two-point chain line) shows a situation in which the electric energy stored in the capacitive element C1 is insufficient, that is, the driving voltage Vc1 has the same waveform as the driving voltage Vc1 shown in FIG. 2.

In the example of FIG. 4, in the fourth period T4 of the second half cycle in the figure, the detection result (driving voltage Vc1) of the detection unit 53 is lower than the first threshold Vth1, so the fourth period of the second half cycle The period T4 becomes a detection period. Then, the changing unit 62 changes the target period (the first period T1 from the first period T1 of the third half period) from the first target period after the end of this detection period (the fourth period T4 of the second half period), that is, from the first period T1 of the third half period. One period T1) is extended. At this time, the changing unit 62 extends the target period until the detection result (driving voltage Vc1) of the detecting unit 53 reaches the second threshold value Vth2. Therefore, the first period T1 after the third half period in FIG. 4 is set as a period extended from the preset value. That is, it is the first time point t1 at the end point of the first period T1 (or the start point of the second period T2), and the variable length length is delayed from the detection time point of the phase (zero crossing point) of the phase detection section 3. Thereafter, when the load control device 1 is turned OFF (the load 7 is turned off), the length of the target period (the first period T1) is reset to a preset value.

Here, the second threshold value Vth2 is larger than the first threshold value Vth1 (Vth1 <Vth2), but is not limited to this value. For example, the second threshold value Vth2 and the first threshold value Vth1 may be the same value, or The second threshold value Vth2 is smaller than the first threshold value Vth1.

According to the configuration of this modification, the extension time of the target period generated by the changing section 62 becomes a variable length time determined in accordance with the detection result of the detection section 53. Therefore, it is unlikely that the target period will be extended longer than necessary or the target period will be generated. The disadvantage of insufficient extension time.

(4.2) Other modifications

Hereinafter, modifications of the first embodiment will be listed.

The load control device 1 according to the first embodiment and the first modification is not limited to the load 7 using an LED element as a light source, and can also be applied to a light source having a high-impedance circuit with a capacitive input circuit and a small current. Examples of such a light source include an organic EL (Electroluminescence) element. The load control device 1 can be applied to, for example, a load 7 of various light sources such as a discharge lamp.

Further, the load 7 controlled by the load control device 1 is not limited to a lighting load, and may be, for example, a heater or a fan. In the case where the load 7 is a heater, the load control device 1 adjusts the amount of heat generated by the heater by adjusting the average power supplied to the heater. In addition, the load 7 is a fan, and the load control device 1 constitutes a regulator that adjusts the rotation speed of the fan.

In addition, the bidirectional switch 2 is not limited to an enhanced n-channel MOSFET, and may be composed of, for example, two IGBTs (Insulated Gate Bipolar Transistor) connected in reverse series. Further, in the bidirectional switch 2, the rectifying element (diode) for realizing the unidirectional ON state is not limited to the parasitic diodes of the switching elements Q1 and Q2, and may also be an external diode. The diodes can be built in the same packages as the switching elements Q1 and Q2, respectively. Further, the bidirectional switch 2 may be, for example, a semiconductor device having a double-gate (double-gate) structure using a semiconductor material having a wide band gap such as GaN (gallium nitride). With this configuration, reduction in the conduction loss of the bidirectional switch 2 can be pursued.

In addition, switching the power supply 52 can also directly generate the control voltage Vc2 from the full-wave rectified AC voltage Vac without going through the step-down power supply 51. Further, the control unit 61 may switch whether or not to execute the generation operation of generating electric energy (control power) stored in the capacitive element C2 by controlling the switching power supply 52. In this case, the detection unit 53 can also detect the amount of electric energy (control power) stored in the capacitive element C2 of the switching power supply 52. The detection unit 53 detects, for example, the magnitude of the control voltage Vc2 of the voltage across the capacitive element C2. In this case, the changing unit 62 extends the target period when the detection result (control voltage Vc2) of the detecting unit 53 does not reach a predetermined threshold.

In addition, in the control of the two-way switch 2, it is also possible to control the "two-way ON state" instead of the "two-way ON state", and conversely to control the "two-way ON state" instead of the "forward ON state". In addition, it is also possible to control the "bidirectional OFF state" instead of the "bidirectional OFF state" and to control the "bidirectional OFF state" instead of the "reverse ON state". That is, the two-way switch 2 need not change the state of the conducting state or the non-conducting state.

In addition, the control method of the bidirectional switch 2 performed by the control circuit 6 is not limited to the above example. For example, the first control signal Sb1 and the second control signal Sb2 can be turned "ON" by interacting with the same cycle as the AC voltage Vac. Way of signal. In this case, the bidirectional switch 2 is turned on while the switching element on the high potential side of the AC voltage Vac among the switching elements Q1 and Q2 is turned on. That is, in this modification, so-called reverse phase control is realized, and a pair of input terminals 11 and 12 are conducted between the zero-cross point of the AC voltage Vac and halfway through the half cycle. In this case, the on-time of the bidirectional switch 2 can be adjusted by adjusting the phase difference between the first control signal and the second control signal and the AC voltage Vac.

Further, the control method of the control section 61 of the load control device 1 may be a general-purpose control method that can correspond to any of the positive phase control method and the reverse phase control method.

In addition, the control unit 61 is not limited to a configuration in which whether or not the power supply unit 5 performs a production operation is switched by the first power signal Ss1. For example, the control unit 61 may be a switch that cuts off the switch provided between at least one of the pair of input terminals 11 and 12 and the power supply unit 5 (step-down power supply 51), and electrically cuts off the power supply unit 5 from the AC power supply 8. To stop the composition of operations.

The detection unit 53 is not limited to a configuration that continuously detects the magnitude of the electric energy (the magnitude of the driving voltage Vc1) stored in the capacitive element C1, and may detect only a part of a half cycle of the AC voltage Vac. For example, the detection unit 53 may detect the magnitude of the electric energy stored in the capacitive element C1 only in the fourth period T4.

Further, the target period extended by the changing unit 62 may be constituted by at least one of the first period T1 and the fourth period T4, and is not limited to the first period T1. That is, the target period may be the fourth period T4, or may be a period of both the first period T1 and the fourth period T4. In the case where the fourth period T4 is included in the target period, the changing unit 62 extends the target period (fourth period T4) by making the start point (time point t3) of the fourth period T4 earlier. For example, in the first period T1, when the detection result of the detection unit 53 is lower than the threshold Vth1, the changing unit 62 may extend the fourth period in the same half cycle as the first period T1.

In addition, the changing unit 62 is not limited to a configuration in which the target period is extended from the first target period after the end of the detection period when the detection result of the detection unit 53 is lower than the threshold Vth1 during the detection period. This period can be extended from the second target period after the end of this detection period. Further, in the target period (first period T1), when the detection result of the detection unit 53 is lower than the threshold value Vth1, the changing unit 62 may extend the target period from this target period (first period T1).

In addition, the changing unit 62 is not limited to a configuration in which, once the target period is extended, the extended target period is continued to be applied until the load control device 1 is turned off. For example, it may be determined whether the target period is extended for each target period. Thereby, in the case where the electric energy stored in the capacitive element C1 is temporarily insufficient, etc., if the electric energy stored in the capacitive element C1 returns to a normal value, the length of the target period is reset to a preset value.

The detection unit 53 may be provided in the control circuit 6, for example. In this case, for example, if a capacitive element C1 is connected to the A / D conversion input terminal of the control circuit 6, the driving voltage Vc1 is input to the control circuit 6 as an analog value.

The switch driving unit 9 is not a necessary configuration of the load control device 1 and may be omitted as appropriate. When the switch driving section 9 is omitted, the control circuit 6 directly drives the bidirectional switch 2. When the switch driving section 9 is omitted, the step-down power supply 51 may be omitted.

In addition, the first time point t1 is not limited to the generation time point of the first detection signal ZC1 or the second detection signal ZC2, and may also be a certain delay from the generation time point of the first detection signal ZC1 or the second detection signal ZC2. Time point of time (for example, 300 [μs]). The delay time is not limited to 300 [μs], and can be appropriately set in a range of 0 [μs] to 500 [μs].

In addition, the third time point t3 may be earlier than the end point (zero crossing point) t4 of the half cycle, and the length from the third time point t3 to the end point t4 of the half cycle may be appropriately set. For example, in the case where the time length from the first time point t1 to the third time point t3 is shorter than the half cycle by a predetermined length, the predetermined time is not limited to 300 [μs], but may be 100 [μs] to 500 The range of [μs] is appropriately set.

The diodes D1 and D2 of the first embodiment are not necessary components of the load control device 1, and the diodes D1 and D2 may be appropriately omitted.

In addition, in the first embodiment, the case where the load control device 1 is a two-wire type is described, but it is not limited to this configuration. The load control device 1 may be, for example, a so-called three-wire type that can be connected to three electric wires. Switches, or so-called four-way switches that can be connected to four wires. In the case where the load control device 1 constitutes a three-way switch, by combining two load control devices 1, for example, the power-on state of the load 7 can be switched at the upper part and the lower part 2 of the stairs of the building.

In addition, the comparison between two values such as the AC voltage Vac and the predetermined value Vzc is "above", and includes both the case where the two values are equal and the case where one of the two values exceeds the other. However, it is not limited to this, and the "above" described herein may be synonymous with "greater" in the case where only one of the two values exceeds the other. That is, whether the two values are equal or not can be arbitrarily changed according to the setting of the predetermined value Vzc, etc. Therefore, there is no technical difference between "above" and "larger". Similarly, references to "not reached" can be synonymous with "below".

(Embodiment 2)

As shown in FIG. 5, the load control device 1A of this embodiment is different from the load control device 1 of the first embodiment in that the load control device 1A further includes a stopper 63 that stops the switching operation of the switching power supply 52. Hereinafter, the same reference numerals are given to the same configurations as those in the first embodiment, and descriptions thereof are appropriately omitted.

The stopping unit 63 electrically cuts off the switching power supply 52 from the AC power supply 8 or stops the switching operation of the switching power supply 52 during the exclusion period. The "excluded period" mentioned here refers to a period including the detection time point when the phase detection unit 3 detects the phase, and when the zero crossing point is detected by the phase detection unit 3, the exclusion period is included. Period with zero crossings. In this embodiment, the stopper 63 is included in the control circuit 6A. The stopper 63 increases the input impedance of the step-down power source 51 by stopping the operation of the first circuit 511 with the first power signal Ss1, and stops the generation operation of the step-down power source 51, for example. When the generating operation of the step-down power source 51 is stopped by the first power signal Ss1, the switching power source 52 is electrically cut off from the AC power source 8.

Between the switching operation of the switching power supply 52, the switching of the switching element causes the impedance of the power supply unit 5 to change, and the current flowing from the AC power supply 8 to the power supply unit 5 may cause ripples. In other words, a DC-DC converter with a switching method such as the switching power supply 52 is more efficient than a power supply circuit with a series regulator method, but it is easily a source of noise. When a ripple is generated in the current flowing from the AC power source 8 to the power source unit 5, the ripple may be affected by the current, and the phase detection accuracy of the AC voltage Vac of the phase detection unit 3 may be reduced. That is, the phase detection unit 3 monitors a voltage of a small degree [V] in order to detect the zero crossing point of the AC voltage Vac, so even if the current fluctuates slightly due to the influence of noise generated by switching the power supply 52, There is a case where the detection accuracy of the phase is reduced.

Therefore, the load control device 1A of this embodiment, as shown in FIG. 6, by the stop unit 63, will switch the power supply during the exclusion period T0 including the detection time point (time point t11) when the phase detection unit 3 detects the phase 52 is electrically disconnected from the AC power source 8. In Figure 6, the AC voltage "Vac", the first detection signal "ZC1", the second detection signal "ZC2", the first control signal "Sb1", the second control signal "Sb2", and the first power signal "Ss1" are displayed. And the driving voltage "Vc1".

That is, the switching power supply 52 is not electrically connected to the AC power supply 8 continuously, but is electrically disconnected from the AC power supply 8 during the exclusion period T0. The exclusion period T0 is, as shown in FIG. 6, the detection time point of the phase (zero crossing point) including the phase detection section 3, that is, the time point t11 of the generation time point of the first detection signal ZC1 or the second detection signal ZC2. The period prescribed by the method. In this embodiment, the starting point t21 of the exclusion period T0 is set to the first In the fourth period T4 (period from t3 to t4), the end point t22 of the exclusion period T0 is set within the first period T1 (period from t0 to t1). That is, the exclusion period T0 is defined as two periods spanning the fourth period T4 and the first period T1. More specifically, the end point t22 of the exclusion period T0 is set to a period (a period from t11 to t1) after the detection time (time point t11) of the phase of the phase detection unit 3 in the first period T1. Thereby, the detection time point (time point t11) of the phase of the phase detection unit 3 is included in the exclusion period T0.

Specifically, the stopping unit 63 increases the input impedance of the step-down power supply 51 by stopping the operation of the first circuit 511 with the first power signal Ss1 during the exclusion period T0 in the half cycle of the AC voltage Vac, and stops the drop. The generation of the voltage source 51 operates. When the generation operation of the step-down power supply 51 is stopped by the first power signal Ss1, the switching power supply 52 is electrically cut off from the AC power supply 8. That is, from the start point t21 set in the fourth period T4 (the period from t3 to t4) to the end point t22 set in the first period T1 (the period from t0 to t1), the stop unit 63 causes The first power signal Ss1 is an "OFF" signal. Accordingly, in the fourth period T4 and the excluded period T0 (the period from t21 to t22) in the first period T1, the generation operation of the step-down power source 51 is stopped, and the switching power source 52 is electrically cut off from the AC power source 8.

Thereby, in the exclusion period T0, the impedance variation of the power supply unit 5 due to the switching operation of the switching power supply 52 is suppressed, so that the current flowing from the AC power supply 8 to the power supply unit 5 is less prone to ripple. As a result, in the detection time point (time point t11) included in the exclusion period T0, the decrease in the detection accuracy of the phase by the phase detection section 3 is suppressed.

The end point t22 of the exclusion period T0 may be made to coincide with the phase detection time point (time point t11) of the phase detection unit 3. That is, after the phase is detected by the phase detection unit 3, the switching operation of the switching power supply 52 is not affected, and the precision of the phase detection performed by the phase detection unit 3 is not affected. Therefore, the phase of the phase detection unit 3 during the exclusion period T0 may also be excluded. The detection time ends.

Here, switching the power supply 52 does not stop the conversion operation as soon as the AC power supply 8 is electrically cut off. Instead, the charge is stored in the capacitive element C1 between the first power signal Ss1 being "ON" and the conversion is continued. Operation. That is, if sufficient electric energy (driving power) is stored in the capacitive element C1, the switching power supply 52 can continue the switching operation even during the exclusion period T0.

Furthermore, in the present embodiment, the changing unit 62 is configured to extend the target period by the shortened amount of time by reducing the excluded period T0 by a shortened amount of time. That is, as shown in FIG. 7, the load control device 1A of this embodiment uses the changing unit 62 to reduce the exclusion period T0 in accordance with the detection result of the detection unit 53, so that the target period is extended by the shortened amount of the exclusion period T0. In the example of FIG. 7, the changing unit 62 reduces the exclusion period T0 by reducing the exclusion period T0 by the amount of time equivalent to the length of the entire exclusion period T0. In the example of FIG. 7, the fourth period T4 is extended by eliminating the period T0 that excludes a total of two periods between the fourth period T4 and the first period T1 and extending the period between both the fourth period T4 and the first period T1. And the first period T1 is a target period. FIG. 7 is a timing chart similar to FIG. 6 when the electric energy stored in the capacitive element C1 is insufficient due to the load 7.

In other words, the changing unit 62 reduces the excluded period T0 included in the target period, and reduces the period during which the generation operation of the step-down power supply 51 is stopped (the excluded period T0). Thereby, at least a part of the time period T0 except when the generation operation of the step-down power supply 51 is stopped is converted into a target period during which the step-down power supply 51 is operated, and the target period is substantially extended.

Specifically, if the detection result of the detection unit 53 does not reach the predetermined threshold Vth1 (refer to FIG. 7), the changing unit 62 reduces the exclusion period T0 and extends the target period (both the first period T1 and the fourth period T4) to the exclusion period. The amount of time to shorten T0. For example, as shown in Figure 7, in the third period of the second half cycle of the figure When the detection result of the detection unit 53 is lower than the threshold value Vth1 during the period T3, the third period T3 of the second half period becomes the detection period. Then, the changing unit 62 reduces the exclusion period T0 from the first target period after the end of this detection period (the third period T3 of the second half period), that is, from the fourth period T4 of the second half period, so that The target period is extended.

In this way, when the electric energy stored in the capacitive element C1 is insufficient, the detection section 53 detects a decrease in electric energy, and the change section 62 causes the power supply section 5 to perform the target period (the first period T1 and The fourth period T4) is extended. Therefore, the electric energy (driving power) generated in the power supply unit 5 during the target period is increased by the length of the target period, and as a result, the shortage of the electric energy stored in the capacitive element C1 is suppressed.

However, the changing unit 62 is not limited to a configuration that reduces the exclusion period T0 by making the exclusion period T0 absent. For example, it may be a configuration that reduces the length of the exclusion period T0 by half, or reduces the length of the exclusion period T0 by one Composition of time length, etc.

In addition, as a modification of the second embodiment, the stopping unit 63 may stop the switching operation of the switching power supply 52 without electrically cutting off the switching power supply 52 from the AC power supply 8 during the exclusion period T0. Specifically, as shown in FIG. 8, the stopping unit 63 stops the operation of the second circuit 521 by the second power signal Ss2 and stops the switching operation of the switching power supply 52. In Figure 8, the AC voltage "Vac", the first detection signal "ZC1", the second detection signal "ZC2", the first control signal "Sb1", the second control signal "Sb2", and the first power signal "Ss1" are displayed. , The second power signal "Ss2", and the driving voltage "Vc1".

In this case, during the exclusion period T0, the ripple of the current flowing from the AC power supply 8 to the power supply section 5 due to the switching of the switching element of the switching power supply 52 is also suppressed. Excluded period T0 compared to AC voltage The half cycle of Vac is a very short period. Therefore, the operation of the control circuit 6 and the like is maintained by the electric energy (control power) stored in the capacitive element C2 of the switching power supply 52. However, in this case, even if the exclusion period T0 is reduced by a shortened amount of time, the target period is not extended by the shortened amount of time.

The configuration (including modifications) of the load control device 1A of the second embodiment can be appropriately combined with the configuration of the first embodiment (including modifications).

(to sum up)

As described above, the first aspect of the load control device 1 includes a bidirectional switch 2, a phase detection section 3, a power supply section 5, a detection section 53, a control section 61, and a change section 62. For the AC power source 8, the bidirectional switch 2 is electrically connected in series with the load 7, and the AC voltage Vac supplied to the load 7 is phase-controlled. The phase detection unit 3 detects the phase of the AC voltage Vac. The power supply unit 5 includes a capacitive element C1 that stores electric energy, and is electrically connected in parallel with the bidirectional switch 2. The electric power generation operation is performed by supplying power from the AC power source 8. The detecting unit 53 detects the magnitude of the electric energy stored in the capacitive element C1. The control unit 61 supplies power from the capacitive element C1 of the power supply unit 5 and controls the bidirectional switch 2 and the power supply unit 5. Based on the phase detected by the phase detection unit 3, the control unit 61 divides a half period consisting of a period between two consecutive zero crossings of the AC voltage Vac into a first period T1, a second period T2, and a third period T3 and the fourth period T4. The control unit 61 causes the two-way switch 2 to be in a non-conducting state during the first period T1 and the fourth period T4, and causes the power supply unit 5 to operate. The control unit 61 turns on the bidirectional switch 2 in the second period T2 and stops the generation operation of the power supply unit 5. The control unit 61 makes the bidirectional switch 2 in a non-conducting state during the third period T3, and stops the generation operation of the power supply unit 5. When the detection result of the detection unit 53 does not reach the threshold value Vth1, the changing unit 62 extends a target period composed of at least one of the first period T1 and the fourth period T4.

With this configuration, when the electric energy stored in the capacitive element C1 is insufficient, the detection unit 53 detects a decrease in electric energy, and the change unit 62 extends the period of time for which the power source unit 5 performs the operation of generating electric energy. Therefore, the electric energy generated in the power supply unit 5 during the target period is increased by the length of the target period, and as a result, the shortage of the electric energy stored in the capacitive element C1 is suppressed. That is, according to this, the load control device 1 becomes less prone to the shortage of the electric energy stored in the capacitive element C1 due to the load 7, and the abnormal operation of the load control device 1 or the load 7 due to the lack of electric energy can be suppressed. occur. Therefore, depending on the load control device 1, there are advantages such that it can be compatible with more types of loads 7.

The second aspect of the load control device 1 is preferably such that in the first aspect, the load control device 1 further includes an interface portion 4 to input an input level of an end point (second time point t2) of the second period T2 in a predetermined half cycle. According to this structure, the length of the ON time during which the bidirectional switch 2 is turned on can be adjusted according to the input level of the interface portion 4. However, this configuration is not necessary for the load control device 1, and the mesial portion 4 may be appropriately omitted.

The load control device 1 of the third aspect is preferably configured such that, in the first or second aspect, the changing unit 62 is configured such that, during the detection period, when the detection result is lower than the threshold value Vth1, The initial target period is extended. The detection period includes any one of the first period T1, the second period T2, the third period T3, and the fourth period T4. With this configuration, since the target period is extended immediately after the detection result of the detection unit 53 is lower than the threshold value Vth1, it becomes easy to avoid a shortage of electric energy stored in the capacitive element C1.

The load control device 1 of the fourth aspect is preferably such that, in any of the first to third aspects, the changing unit 62 is configured to extend the target period by a certain time ΔT minutes when the detection result does not reach the threshold value Vth1. . With this configuration, the processing used to extend the target period is simplified. However, this configuration is not necessary for the load control device 1, and the extension time of the target period may be a variable length.

The load control device 1 of the fifth aspect is preferably configured such that, in any of the first to third aspects, the changing unit 62 is configured to detect the case where the detection result does not reach the first threshold value Vth1 which is the threshold value Vth1. The period is extended until the detection result reaches the second threshold value Vth2. With this configuration, when the detection result of the detection unit 53 is lower than the first threshold value Vth1, the target period is extended until the electric energy stored in the capacitive element C1 returns to a certain level, so it becomes easy to avoid storing in the capacitive element C1. Power shortage.

The sixth aspect of the load control device 1 is preferably such that, in any of the first to fifth aspects, the power supply unit 5 includes a switching power supply 52. The switching power supply 52 performs a conversion operation for converting a DC voltage (driving voltage Vc1) supplied from the capacitive element C1 to a control voltage Vc2 by a switching operation of the switching element. In this case, it is preferable that the load control device 1 further includes a stopper 63. The stopping unit 63 electrically cuts off the switching power supply 52 from the AC power supply 8 or stops the switching operation of the switching power supply 52 during the period T0 excluding the time when the phase detection unit 3 detects the phase. The exclusion period T0 is set to at least one of the first period T1 and the fourth period T4. With this configuration, at the point of time when the phase detection section 3 detects the phase, ripples caused by the current flowing from the AC power supply 8 to the power supply section 5 due to the switching of the switching element of the switching power supply 52 are suppressed. Therefore, the detection accuracy of the phase of the phase detection unit 3 due to the influence of noise generated by the switching power supply 52 is suppressed from being reduced. If the detection accuracy of the phase of the AC voltage Vac of the phase detection unit 3 is improved, it becomes easier to maintain the normal operation of the load control device 1 or the load 7. However, this configuration is not necessary for the load control device 1, and the stop section 63 may be omitted as appropriate.

The load control device 1 of the seventh aspect is preferably configured such that, in the sixth aspect, the changing unit 62 is configured to reduce the exclusion period T0 by a shortened amount of time, and extend the target period by the shortened amount of time. With this configuration, at least a part of the period T0 except when the generation operation of the step-down power supply 51 is stopped is converted into a step-down power supply. 51 The target period for generating operations is performed, so the target period can be extended without changing the start and end points of the target period.

Claims (8)

A load control device includes a bidirectional switch. For an AC power source, the bidirectional switch is electrically connected in series with a load to phase control an AC voltage supplied to the load; a phase detection section detects a phase of the AC voltage; a power supply section includes: The capacitive element storing electric energy is electrically connected in parallel with the bidirectional switch, and the electric energy generation operation is performed by the supply of electric power from the AC power source; the detecting unit detects the magnitude of the electric energy stored in the capacitive element; the control unit Receiving the supply of electric energy from the capacitive element of the power supply section, controlling the bidirectional switch and the power supply section, and according to the phase detected by the phase detection section, the period between zero consecutive crossings of the AC voltage will be 2 times The formed half cycle is divided into a first period, a second period, a third period, and a fourth period; during the first period and the fourth period, the bidirectional switch is made non-conductive and the power supply section Execute the generating operation; in the second period, make the bidirectional switch in an on state and stop the generating operation of the power supply section; in the third period During the period, the bidirectional switch is made non-conductive, and the generation operation of the power supply section is stopped; and the change section, when the detection result of the detection section does not reach the threshold, will be determined by at least the first period and the fourth period. The period covered by one period is extended. For example, the load control device of the scope of patent application No. 1 further includes an interface portion, and an input level specifying an end point of the second period in the half cycle is input. For example, the load control device of the first scope of the patent application, wherein the change unit is configured to detect the first period, the second period, the third period, and the fourth period. If the detection result is lower than the threshold during the period, the target period is extended from the first target period after the end of the detection period. For example, the load control device in the second scope of the patent application, wherein the change unit is configured to detect the first period, the second period, the third period, and the fourth period. If the detection result is lower than the threshold during the period, the target period is extended from the first target period after the end of the detection period. For example, the load control device according to any one of claims 1 to 4, wherein the changing unit is configured to extend the subject period for a certain period of time if the detection result does not reach the threshold. For example, the load control device according to any one of claims 1 to 4, wherein the changing unit is configured to extend the subject period until the detection when the detection result does not reach the first threshold as the threshold. As a result, the second threshold is reached. For example, the load control device according to any one of claims 1 to 4, wherein the power supply section has a switching power supply, and the switching power supply executes the conversion of the DC voltage supplied from the capacitive element through the switching operation of the switching element. To control the voltage conversion operation, the load control device further includes a stop section that electrically cuts off the switching power supply from the AC power supply during the period excluding the time when the phase detection section detects the phase. Or stop the conversion operation of the switching power supply; the excluded period is set to at least one of the first period and the fourth period. For example, the load control device of the seventh scope of the patent application, wherein the changing unit is configured to reduce the excluded period by a shortened amount of time, and thereby extend the target period by the shortened amount of time.