JP2018107051A - Load controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load controller capable of corresponding to more various kinds of load.SOLUTION: A control part divides a half period formed by a period of two zero cross points in which an AC voltage Vac is continued on the basis of a phase detected in a phase detection part into a first period T1, a second period T2, a third period T3, and a fourth period T4. The control part sets a bidirectional switch to a non-conductive state in the first and fourth periods T1 and T4, and allows a power supply part to perform a generation operation. The control part sets the bidirectional switch to the conductive state in the second period T2, and stops the generation operation of the power supply part. The control part sets the bidirectional switch to the non-conductive state in the third period T3, and stops the generation operation of the power supply part. A changing part extends a target period formed by at least one period of the first and fourth period T1 and T4 in a case where a detection result of a detection part is less than a threshold value Vth1.SELECTED DRAWING: Figure 3

Description

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

  2. Description of the Related Art Conventionally, a dimming device that dims an illumination load is known (for example, Patent Document 1).

  The dimming device described in Patent Document 1 includes a pair of terminals, a control circuit unit, a switching power source that supplies control power to the control circuit unit, and a dimming operation unit that sets the dimming level of the lighting load. I have.

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

  The control circuit unit includes a switch unit that controls the phase of the AC voltage supplied to the illumination load, a switch drive unit that drives the switch unit, and a control unit that controls the switch drive unit and the switching power supply.

  The switching power supply is connected to the switch unit in parallel. The switching power source converts the AC voltage of the AC power source into a control power source. The switching power supply includes an electrolytic capacitor that stores a control power supply.

  The control unit is supplied with control power from the switching power supply through an electrolytic capacitor. The control unit includes a microcomputer. The microcomputer performs anti-phase control for cutting off the power supply to the illumination load during the period of every half cycle of the AC voltage according to the dimming level set by the dimming operation unit.

JP 2013-149498 A

  By the way, in a load control device such as a light control device, various loads such as various illumination loads can be electrically connected. Therefore, depending on the load connected to the load control device, the load control device or the load may operate abnormally.

  This invention is made | formed in view of the said reason, and it aims at providing the load control apparatus which can respond to more types of load.

  A load control device according to an aspect of the present invention includes a bidirectional switch, a phase detection unit, a power supply unit, a detection unit, a control unit, and a change unit. The bidirectional switch is electrically connected in series with a load with respect to an AC power source, and phase-controls the AC voltage supplied to the load. The phase detector detects a phase of the AC voltage. The power supply unit includes a capacitive element that stores electrical energy, is electrically connected to the bidirectional switch in parallel, and performs a generation operation of generating the electrical energy by power supplied from the AC power supply. The detection unit detects the magnitude of the electric energy accumulated in the capacitive element. The control unit is supplied with the electrical energy from the capacitive element of the power supply unit, and controls the bidirectional switch and the power supply unit. The control unit has a first period, a second period, and a third period based on a phase detected by the phase detection unit based on a half cycle including a period between two consecutive zero-cross points of the AC voltage. And the fourth period. In the first period and the fourth period, the control unit turns off the bidirectional switch, and causes the power supply unit to perform the generation operation. In the second period, the control unit turns on the bidirectional switch and stops the generation operation of the power supply unit. In the third period, the control unit turns off the bidirectional switch and stops the generation operation of the power supply unit. The change unit extends a target period including at least one of the first period and the fourth period when the detection result of the detection unit is less than a threshold value.

  The present invention has an advantage that it can cope with more kinds of loads.

FIG. 1 is a schematic circuit diagram of a load control apparatus according to Embodiment 1 of the present invention. FIG. 2 is a timing chart showing the operation of the above load control apparatus. FIG. 3 is a timing chart showing an operation in the case where the electrical energy accumulated in the capacitive element is insufficient in the load control device. FIG. 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 the load control device according to the second embodiment of the present invention. FIG. 6 is a timing chart showing the operation of the above load control apparatus. FIG. 7 is a timing chart showing an operation in the case where the electrical energy accumulated in the capacitive element is insufficient in the load control device. FIG. 8 is a timing chart showing the operation of the load control device according to the modification of the second embodiment of the present invention.

  The configuration described below is merely an example of the present invention, and the present invention is not limited to the following embodiment, and the scope of the invention does not depart from the technical idea of the present invention, even if it is other than this embodiment. If so, various changes can be made according to the design and the like.

(Embodiment 1)
(1) Outline As shown in FIG. 1, the load control device 1 according to the present embodiment includes a bidirectional switch 2 that is electrically connected in series to a load 7 with respect to an AC power supply 8. The load control device 1 controls the phase of the AC voltage Vac supplied from the AC power supply 8 to the load 7 by the bidirectional switch 2. The “phase control” referred to here is an AC voltage supplied (applied) to the load 7 by changing a phase angle (conduction angle) at which energization to the load 7 is started or ended every half cycle of the AC voltage Vac. This means a method for controlling Vac. That is, the load control device 1 controls the load 7 such as an illumination load, a heater, or a fan by controlling the phase of the AC voltage Vac supplied to the load 7.

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

  Here, the load control device 1 according to the present embodiment is a two-wire type, and the AC power supply 8 is connected to the AC power supply 8 so that the bidirectional switch 2 is electrically connected to the load 7 in series. It is electrically connected to the load 7. In other words, the load control device 1 is connected to two wires, that is, a wire connected to the AC power supply 8 and a wire connected to the load 7, and the bidirectional switch 2 is inserted between the two wires. Therefore, if the bidirectional switch 2 is in the conductive state, the voltage from the AC power supply 8 is applied to the load 7 and is supplied to the load 7. If the bidirectional switch 2 is in the nonconductive state, the voltage from the AC power supply 8 is The voltage is applied to the load control device 1 and the power supply to the load 7 is stopped. The load control device 1 acquires the power for operation of the load control device 1 itself from the AC power supply 8 through these two wires, and controls the bidirectional switch 2 and the like. That is, when the bidirectional switch 2 is in a non-conducting state, the load control device 1 generates its own power for operation in the power supply unit 5 described later, so that the two-wire load control device 1 can be realized. is there.

(2) Configuration As illustrated in FIG. 1, the load control device 1 according to the present embodiment includes a pair of input terminals 11 and 12, a bidirectional switch 2, a phase detection unit 3, an interface unit 4, a power supply unit 5, and a control circuit. 6, a switch drive unit 9, a detection unit 53, and diodes D1 and D2. The control circuit 6 includes a control unit 61 and a change unit 62. The “input terminal” here may not be a component (terminal) for connecting an electric 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 includes, for example, two elements, a first switch element Q1 and a second switch element Q2, which are electrically connected in series between the input terminals 11 and 12. For example, each of the switch elements Q1 and Q2 is a semiconductor switch element made of an enhancement type n-channel MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

  The switch elements Q1 and Q2 are connected in a so-called reverse series between the input terminals 11 and 12. That is, the sources of the switch elements Q1 and Q2 are connected to each other. The drain of the switch element Q1 is connected to the input terminal 11, and the drain of the switch element Q2 is connected to the input terminal 12. The sources of both switch elements Q 1 and Q 2 are connected to the ground of the power supply unit 5. The ground of the power supply unit 5 serves as a reference potential for the internal circuit of the load control device 1.

  The bidirectional switch 2 can be switched between four states by a combination of ON and OFF of the switch elements Q1 and Q2. The four states include a bidirectional off state in which both switch elements Q1 and Q2 are both off, a bidirectional on state in which both switch elements Q1 and Q2 are both on, and only one of the switch elements Q1 and Q2 is on. There are two types of one-way ON states. In the unidirectional ON state, the pair of input terminals 11 and 12 are electrically connected in one direction from the ON switch element of the switch elements Q1 and Q2 through the parasitic diode of the OFF switch element. For example, when the switch element Q1 is on and the switch element Q2 is off, the first one-way on state in which current flows from the input terminal 11 toward the input terminal 12 is set. Further, when the switch element Q2 is on and the switch element Q1 is off, the second one-way on state in which current flows from the input terminal 12 toward the input terminal 11 is set. Therefore, when the AC voltage Vac is applied from the AC power supply 8 between the input terminals 11 and 12, the first one-way ON state is “in the positive polarity of the AC voltage Vac, that is, in the half cycle of the input terminal 11 being positive. The “forward ON state” and the second unidirectional ON state are “reverse ON state”. On the other hand, in the negative polarity of the AC voltage Vac, that is, in the half cycle in which the input terminal 12 is positive, the second one-way on state is the “forward on state” and the first one-way on state is the “reverse on state”. It becomes.

  Here, in the bidirectional switch 2, both the “bidirectional on state” and the “forward on state” are conductive, and both the “bidirectional off state” and the “reverse on state” are nonconductive. State.

  The phase detector 3 detects the phase of the AC voltage Vac applied between the input terminals 11 and 12. The “phase” here includes the zero cross 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 the zero cross point of the AC voltage Vac is detected. The phase detection unit 3 includes a diode D31, a first detection unit 31, a diode D32, and a second detection unit 32. The first detection unit 31 is electrically connected to the input terminal 11 via the diode D31. The second detection unit 32 is electrically connected to the input terminal 12 via the diode D32. The first detector 31 detects a zero cross point when the AC voltage Vac shifts from a negative half cycle to a positive half cycle. The second detector 32 detects a zero cross point when the AC voltage Vac shifts from a positive half cycle to a negative half cycle.

  That is, when the first detection unit 31 detects that the voltage having the input terminal 11 as the positive electrode has shifted from a state less than a specified value to a state greater than or equal to the specified value, the first detection unit 31 determines that it is a zero cross point and controls the first detection signal ZC1. Output to circuit 6. Similarly, when the second detection unit 32 detects that the voltage having the input terminal 12 as the positive electrode has shifted from a state below the specified value to a state equal to or higher than the specified value, the second detecting unit 32 determines that it is a zero-cross point, and generates the second detection signal ZC2. Output to the control circuit 6. The specified value is a value (absolute value) set near 0 [V]. For example, the specified value of the first detector 31 is about several [V], and the specified value of the second detector 32 is about several [V]. Therefore, the detection point of the zero cross point detected by the first detection unit 31 and the second detection unit 32 is slightly delayed from the zero cross point (0 [V]) in a strict sense.

  The interface unit 4 receives an input level that defines a phase angle (conduction angle) for starting or ending energization of the load 7 every half cycle of the AC voltage Vac. That is, the input level defines the timing when the bidirectional switch 2 becomes conductive or non-conductive in the half cycle of the AC voltage Vac. In the present embodiment, since the load control device 1 is a light control device, the interface unit 4 receives an operation by a user and receives an input of a light control level as an input level. The interface unit 4 outputs a dimming signal indicating the dimming level to the control circuit 6. The dimming signal is a numerical value or the like that specifies the magnitude of the light output of the load 7 and may include an “OFF level” that turns off the load 7. In the present embodiment, as an example, the interface unit 4 includes a touch panel that accepts a user's touch operation. The interface unit 4 may be configured to output a signal representing an input level (dimming level), and may be, for example, a variable resistor or a rotary switch. Furthermore, the interface unit may be configured by a receiving unit that receives a signal from a remote controller or a communication terminal such as a smartphone.

  In the present embodiment, the interface unit 4 further includes a display unit (indicator) that displays the input level (light control level) that has been input. The interface unit 4 includes, for example, a display unit made up of a plurality of LED elements, and displays the input level according to the number of lighting LED elements.

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

  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). The program may be recorded in advance in a memory of a microcomputer, may be provided by being recorded on a recording medium such as a memory card, or may be provided through an electric communication line. In other words, the program is a program for causing a computer (here, a microcomputer) to function as the control circuit 6.

  The switch drive unit 9 includes a first drive unit 91 that drives the switch element Q1 (on / off control) and a second drive unit 92 that drives the switch element Q2 (on / off control). The first drive unit 91 receives the first control signal Sb1 from the control circuit 6 and applies a gate voltage to the switch element Q1. Accordingly, the first drive unit 91 performs on / off control of the switch element Q1. Similarly, the second drive unit 92 receives the second control signal Sb2 from the control circuit 6 and applies a gate voltage to the switch element Q2. As a result, the second drive unit 92 performs on / off control of the switch element Q2. The first drive unit 91 generates a gate voltage with reference to the source potential of the switch element Q1. The same applies to the second drive unit 92.

  The power supply unit 5 includes a dropper power supply 51 that generates drive power (electric energy) for operating the switch drive unit 9 and the like, and a switching power supply 52 that generates control power. The drive power is power for operating the switch drive unit 9 and the like. The control power is power for operating the interface unit 4 and the control circuit 6. The power supply unit 5 performs a generation operation of generating electrical energy (driving power) by the dropper power supply 51 using the power supplied from the AC power supply 8. Electric energy (driving power) generated by the dropper power supply 51 is converted into control power by the switching power supply 52.

  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. As a result, the AC voltage Vac applied between the input terminals 11 and 12 is full-wave rectified by a diode bridge composed of the diodes D1 and D2 and the parasitic diodes of the switch elements Q1 and Q2, and the power supply Supplied to section 5. Therefore, when the bidirectional switch 2 is in a non-conduction state, the AC voltage Vac (pulsating voltage output from the diode bridge) subjected to full-wave rectification is applied to the power supply unit 5.

  The dropper power supply 51 includes a first circuit 511 and a capacitive element (capacitor) C1. The dropper power supply 51 is a series regulator type power supply circuit, and applies a full-wave rectified AC voltage Vac to step down and smooth the applied voltage to generate a DC drive 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 the drive voltage Vc1 is generated across the capacitive element C1. The dropper power supply 51 supplies the electrical energy accumulated in the capacitive element C1 to the switch drive unit 9 and the switching power supply 52 as drive power. The drive 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 switching type DC-DC converter such as a step-down chopper circuit. When the drive voltage Vc1 is applied from the dropper power supply 51, the applied DC voltage (drive voltage Vc1) is stepped down. A DC control voltage Vc2 is generated. That is, when the drive voltage Vc1 is applied to the second circuit 521, the capacitive element C2 is charged, and the control voltage Vc2 is generated at both ends of the capacitive element C2. The second circuit 521 includes a switching element (semiconductor switch), and generates a control voltage Vc2 by stepping down the drive voltage Vc1 by switching of the switching element. In short, the switching power supply 52 performs a conversion operation for converting the DC voltage supplied from the capacitive element C1 into the control voltage Vc2 by the switching operation of the switching element. Control power generated by the conversion operation of the switching power supply 52 is supplied to the interface unit 4, the control circuit 6, and the like. The control voltage Vc2 is, for example, 3.5 [V].

  Therefore, electrical energy is supplied to the control circuit 6 (control unit 61) from the capacitive element C1 of the power supply unit 5 through the switching power supply 52 during the conversion operation of the switching power supply 52. The control circuit 6 (control unit 61) operates with electric energy (control power) from the power supply unit 5.

  The dropper power supply 51 and the switching power supply 52 are configured to be controllable by the control unit 61. In other words, the control unit 61 has a function of controlling the power supply unit 5. Accordingly, the control unit 61 controls whether or not the power supply unit 5 performs a generation operation for generating electrical energy (driving power) accumulated 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) accumulated in the capacitive element C2.

  In the present embodiment, the control unit 61 controls a semiconductor switch included in the dropper power supply 51 to cause the power supply unit 5 to execute a generation operation and a state in which the generation operation of the power supply unit 5 is stopped. Switch. Specifically, the control unit 61 controls the semiconductor switch of the dropper power supply 51 with the first power supply signal Ss1. The control unit 61 increases the input impedance of the dropper power supply 51 by stopping the operation of the first circuit 511 and stops the generation operation of the dropper power supply 51. When the generation operation of the dropper power supply 51 is stopped by the first power supply signal Ss1, the generation of electric energy (drive power) in the power supply unit 5 is stopped. Further, the control unit 61 controls a switching element included in the switching power supply 52 to switch between a state in which the power supply unit 5 performs the conversion operation and a state in which the conversion operation of the power supply unit 5 is stopped. Specifically, the control unit 61 controls the switching element of the switching power supply 52 with the second power supply signal Ss2. When the conversion operation of the switching power supply 52 is stopped, the generation of electric energy (control power) in the power supply unit 5 is stopped.

  The detection part 53 detects the magnitude | size of the electrical energy accumulate | stored in the capacitive element C1. In the present embodiment, the detection unit 53 is configured to detect the magnitude of the drive voltage Vc1 that is 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 drive voltage Vc1 to the control circuit 6 as a detection value. That is, the detection unit 53 directly detects the magnitude of the electrical energy accumulated in the capacitive element C1 by detecting the voltage across the capacitive element C1 (drive voltage Vc1). Hereinafter, it is assumed that the detection value of the detection unit 53 is equal to the drive voltage Vc1. However, the configuration is not limited to this configuration, and the detection unit 53 indirectly detects the control voltage Vc2 that is the voltage across the capacitive element C2, thereby indirectly determining the magnitude of the electrical energy accumulated in the capacitive element C1. It may be configured to detect automatically.

  The lighting circuit of the load 7 reads the dimming level from the waveform of the AC voltage Vac phase-controlled by the load control device 1 and changes the magnitude of the light output of the LED element. Here, the lighting circuit has a current securing circuit such as a bleeder circuit as an example. Therefore, even when the bidirectional switch 2 of the load control device 1 is non-conductive, it is possible to pass a current through the load 7.

(3) Operation (3.1) Start-up Operation First, the start-up operation at the start of energization of the load control device 1 of the present embodiment will be described.

  According to the load control device 1 configured as described above, when the AC power supply 8 is connected between the input terminals 11 and 12 via the load 7, the AC voltage Vac applied from the AC power supply 8 to the input terminals 11 and 12. Is rectified and supplied to the dropper power supply 51. The drive power generated by the dropper power supply 51 is supplied to the switch drive unit 9 and 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 unit 4, the control circuit 6 and the interface unit 4 are activated.

  When the control circuit 6 is activated, the control circuit 6 determines the frequency of the AC power supply 8 based on the detection signal of the phase detector 3. Then, the control circuit 6 sets parameters such as various times with reference to a numerical table stored in advance in the memory according to the determined frequency. Here, if the dimming level input to the interface unit 4 is “OFF level”, the control circuit 6 maintains the bidirectional switch 2 in the bidirectionally off state, so that the pair of input terminals 11 and 12 are connected. Is maintained in a high impedance state. Thereby, the load 7 maintains a light extinction state.

(3.2) Load Control Operation Next, the load control operation of the load control device 1 of the present embodiment will be described with reference to FIG. In FIG. 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”, the first power supply signal “Ss1”, And the drive voltage “Vc1”.

  In the present embodiment, it is assumed that the first detection signal ZC1 is generated when the first detection signal ZC1 changes from the “H” level (High Level) to the “L” level (Low Level). Further, it is assumed that the second detection signal ZC2 is generated when the second detection signal ZC2 changes from the “H” level to the “L” level. 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 detection unit 3 detects the phase (zero cross point). The first power supply signal Ss1 and the drive voltage Vc1 will be described in the section “(3.3) Control power generation operation”.

  Based on the phase detected by the phase detector 3, the controller 61 divides the half cycle of the AC voltage Vac into a first period T1, a second period T2, a third period T3, and a fourth period T4. Then, the bidirectional switch 2 is controlled. The “half cycle” here is a period between two consecutive zero-cross points of the AC voltage Vac. In the first period T1 and the fourth period T4, the control unit 61 sets the bidirectional switch 2 in a non-conductive state. In the second period T2, the control unit 61 brings the bidirectional switch 2 into a conductive state. In the third period T3, the control unit 61 puts the bidirectional switch 2 in a non-conductive state.

  Hereinafter, the operation of the load control device 1 in the first period T1, the second period T2, the third period T3, and the fourth period T4 will be described in more detail.

  First, the operation of the load control device 1 in a half cycle in which the AC voltage Vac is positive will be described. In the load control device 1, the phase detector 3 detects the zero cross point of the AC voltage Vac that is a reference for phase control. When the AC voltage Vac shifts from the negative half-cycle to the positive half-cycle, when the AC voltage Vac reaches the positive specified value “Vzc”, the first detection unit 31 outputs the first detection signal ZC1. Output. The control unit 61 sets the first time point t1 after the time point t11 when the first detection signal ZC1 is generated, that is, after the detection timing of the phase (zero cross point) in the phase detection unit 3, and at the first time point t1, the first time point t1. The 1 control signal Sb1 and the second control signal Sb2 are turned on. In the example of FIG. 2, the detection timing (time point t11) in the phase detector 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 sets the bidirectional switch 2 to the bidirectional on state. The period from the start point (zero cross point) t0 of the positive half cycle to the first time point t1 is the first period T1. In the first period T1, the control unit 61 turns the first control signal Sb1 and the second control signal Sb2 into “OFF” signals. As a result, in the first period T1, the switch elements Q1 and Q2 are both turned off, and the bidirectional switch 2 is in the bidirectional off state (non-conducting state). Therefore, in the first period T1, power supply from the AC power supply 8 to the load 7 is cut off.

  The second time point t2 is a time point when the ON time having a length corresponding to the dimming signal has elapsed from the detection timing (time point t11) of the phase (zero cross point) in the phase detector 3. At the second time point t2, the controller 61 changes the first control signal Sb1 to the “OFF” signal while maintaining the second control signal Sb2 at the “ON” signal. As a result, in the second period T2 from the first time point t1 to the second time point t2, the switch elements Q1 and Q2 are both turned on, and the bidirectional switch 2 is in the bidirectionally on state (conductive state). Therefore, power is supplied from the AC power supply 8 to the load 7 via the bidirectional switch 2 in the second period T2.

  The third time point t3 is a time point a certain time (for example, 300 [μs]) before the end point (zero cross point) t4 of the half cycle. That is, when the third time point t3 is estimated as the end point t4 when the time obtained by subtracting the first period T1 from the half-cycle time has elapsed from the detection timing (time point t11) of the zero cross point in the phase detector 3. In addition, it is a time point before this end point t4 by a certain time. In the timing chart of FIG. 2, the third time point t3 coincides with the timing at which the AC voltage Vac reaches the positive specified value “Vzc” and the timing at which the AC voltage Vac reaches the negative specified value “−Vzc”. Is shown in FIG. However, in practice, the third time point t3 is determined regardless of the timing at which the AC voltage Vac intersects the positive specified value “Vzc” or the negative specified value “−Vzc”.

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

  In the fourth period T4 from the third time point t3 to the end point (zero cross point) t4 of the half cycle, the switch elements Q1 and Q2 are both turned off, and the bidirectional switch 2 is in the bidirectionally off state (non-conducting state). It becomes.

  The operation of the load control device 1 when the AC voltage Vac is a negative half cycle is basically the same as the positive half cycle.

  In the negative half cycle, when the AC voltage Vac reaches the specified negative value “−Vzc”, the second detection unit 32 outputs the second detection signal ZC2. In the present embodiment, it is set after the generation point of the second detection signal ZC2 from the start point t0 (t4) of the negative half cycle, that is, after the detection timing (time point t11) of the phase (zero cross point) in the phase detector 3. The period up to the first time point t1 is the first period T1. The second time point t2 is a time point when the ON time having a length corresponding to the dimming signal has elapsed from the detection timing (time point t11) of the phase (zero cross point) in the phase detector 3, and the third time point t3 is The time is a certain time (for example, 300 [μs]) before the end point t4 (t0) of the half cycle.

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

  At the second time point t2, the controller 61 changes the second control signal Sb2 to the “OFF” signal while maintaining the first control signal Sb1 at the “ON” signal. At the third time point t3, the control unit 61 turns the first control signal Sb1 and the second control signal Sb2 into “OFF” signals. Thereby, in the third period T3 from the second time point t2 to the third time point t3, only the switch element Q2 is turned off among the switch elements Q1 and Q2, and the bidirectional switch 2 is turned on in the reverse direction (non-conductive state). ) Therefore, power supply from the AC power supply 8 to the load 7 is cut off in the third period T3. In the fourth period T4 from the third time point t3 to the end point t4 of the half cycle, the switch elements Q1 and Q2 are both turned off, and the bidirectional switch 2 is in the bidirectional off state (non-conducting state).

  The load control device 1 of the present embodiment alternately performs the positive half-cycle operation and the negative half-cycle operation described above for each half cycle of the AC voltage Vac, thereby dimming the load 7. Do. Here, since the “bidirectional on state” is a conductive state and the “reverse direction on state” is a nonconductive state, the bidirectional switch 2 is in a conductive state at the end of the second period, that is, at the second time point t2. To non-conducting state. The end point (second time point t2) of the second period is defined by the dimming level input to the interface unit 4. Furthermore, if the positive polarity prescribed value “Vzc” and the negative polarity prescribed value “−Vzc” are fixed values, the phase detection unit 3 detects the phase (zero cross point) from the start point t0 of the half cycle (time point t11). ) Is a substantially fixed length of time.

  Therefore, the time from the start point t0 of the half cycle to the second time point t2, that is, the time obtained by adding up the first period T1 and the second period T2 whose length changes according to the dimming level is “variable time. "" Changes in length according to the light control level. In other words, the phase angle (conduction angle) at the second time point t2 at which the energization of the load 7 is finished every half cycle of the AC voltage Vac changes according to the dimming level. That is, when the light output of the load 7 is decreased, the variable time is defined as short (phase angle is small), and when the light output of the load 7 is increased, the variable time is defined as long (phase angle is large). Therefore, the load control device 1 can change the magnitude of the light output of the load 7 in accordance with the dimming level input to the interface unit 4.

  Further, in the half cycle of the AC voltage Vac, periods (first period T1, third period T3, and fourth period T4) other than the period (second period T2) from the first time point t1 to the second time point t2 are used. ), The bidirectional switch 2 is in a non-conductive state (reverse direction on state or bidirectional off state). The load control device 1 can ensure power supply from the AC power supply 8 to the power supply unit 5 using these periods when the bidirectional switch 2 is in a non-conductive state. The operation of the power supply unit 5 will be described in detail in the section “(3.3) Operation of power supply unit”.

  Here, the expression “from time A” includes time A. For example, “from the first time point” means to include the first time point. On the other hand, the expression “until time A” does not include time A but means immediately before time A. For example, “to the end of the half cycle” means not to include the end of the half cycle, but to the point just before the end of the half cycle.

(3.3) Operation of Power Supply Unit Next, the operation of the power supply unit 5 will be described with reference to FIG.

  Based on the phase detected by the phase detector 3, the controller 61 divides the half cycle of the AC voltage Vac into a first period T1, a second period T2, a third period T3, and a fourth period T4. Then, the power supply unit 5 is controlled. In the first period T1 and the fourth period T4, the control unit 61 causes the power supply unit 5 to perform a generation 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. That is, the power supply unit 5 generates electric energy (driving power) by the power supplied from the AC power supply 8 only in the first period T1 and the fourth period T4 in the half cycle of the AC voltage Vac. I do.

  Specifically, the control unit 61 sets the first power supply signal Ss1 to the “ON” signal (for example, H level) only in the first period T1 and the fourth period T4 in the half cycle of the AC voltage Vac. This causes the power supply unit 5 to perform a generation operation. The control unit 61 stops the generation operation of the power supply unit 5 by setting the first power supply signal Ss1 to an “OFF” signal (for example, L level) in the second period T2 and the third period T3. In short, while the first power supply signal Ss1 is the “ON” signal, the power supply unit 5 performs a generation operation of generating electrical energy (drive power) with the dropper power supply 51. At this time, the switching power supply 52 of the power supply unit 5 performs a conversion operation. On the other hand, the power supply unit 5 stops the generation operation by stopping the generation of electric energy (drive power) in the dropper power supply 51 while the first power supply signal Ss1 is the “OFF” signal. The switching power supply 52 does not stop the conversion operation immediately when the first power supply signal Ss1 becomes the “OFF” signal, but the charge accumulated in the capacitive element C1 while the first power supply signal Ss1 is the “ON” signal. Thus, the conversion operation is continued. That is, if sufficient electric energy (driving power) is accumulated in the capacitive element C1, the load control device 1 can be used even while the generation operation of the electric energy (driving power) in the dropper power supply 51 is stopped. The operation can be continued.

  However, the timing at which the first power supply signal Ss1 changes from the “OFF” signal to the “ON” signal coincides with the third time point t3 when the first control signal Sb1 and the second control signal Sb2 become the “OFF” signal. This is not essential in the load control device 1. For example, the first power supply signal Ss1 may be an “ON” signal at a timing earlier than the third time point t3, that is, at any timing between the second time point t2 and the third time point t3. In this case, the timing at which the first power supply signal Ss1 changes from the “OFF” signal to the “ON” signal is a boundary point between the third period T3 and the fourth period T4. That is, since the bidirectional switch 2 is in a non-conductive state before or after the third time point t3, the first power supply signal Ss1 becomes the “ON” signal at a timing earlier than the third time point t3. Thus, the fourth period T4 may start.

  As the power supply unit 5 operates as described above, the drive voltage Vc1 rises during the first period T1 and the fourth period T4 of the half cycle of the AC voltage Vac, and the second period T2 and the second period T4. In the third period T3, the drive voltage Vc1 decreases. Therefore, focusing on two consecutive half cycles, the driving voltage Vc1 is from the third time point t3 of the first half cycle to the first time point t1 of the next half cycle (that is, the second half cycle). To rise.

  By the way, depending on the load 7, in the first period T1 and the fourth period T4, the power supply unit 5 cannot receive sufficient power supply from the AC power supply 8, and the electric energy accumulated in the capacitive element C1. May not be able to maintain the normal operation of the load control device 1. That is, depending on the load 7, the electrical energy (driving power) generated by the dropper power supply 51 during the half cycle of the AC voltage Vac is consumed by the load control device 1 during the half cycle of the AC voltage Vac. May fall below. In such a case, the electrical energy accumulated in the capacitive element C1 of the dropper power supply 51 gradually decreases every half cycle of the AC voltage Vac. If such a state continues, the electrical energy stored in the capacitive element C1 will eventually become insufficient, and there is a possibility that normal operation of the load control device 1 cannot be maintained. If the drive voltage Vc1 decreases to some extent due to a decrease in the electrical energy stored in the capacitive element C1, for example, the generation of control power in the switching power supply 52 using drive power becomes unstable, or the interface unit 4 Etc. may become unstable. As a result, abnormal operation of the load control device 1 or the load 7 may occur, for example, blinking or flickering of the display unit of the interface unit 4 or blinking or flickering of the load 7.

  Therefore, as illustrated in FIG. 3, the load control device 1 according to the present embodiment determines the length of the target period including at least one of the first period T1 and the fourth period T4. The change unit 62 is configured to change the detection result according to the detection result. FIG. 3 is a timing chart similar to FIG. 2 when the electrical energy accumulated in the capacitive element C1 is insufficient due to the load 7. In the present embodiment, as an example, the first period T1 is the target period. That is, the length of the period (first period T1 and fourth period T4) in which the control unit 61 causes the power supply unit 5 to perform the generation operation is not constant and varies depending on the detection result of the detection unit 53.

  The changing unit 62 extends the target period (the first period T1 in the present embodiment) when the detection result of the detecting unit 53 is less than the predetermined threshold Vth1 (see FIG. 3). Specifically, the changing unit 62 compares the detection result (drive voltage Vc1) of the detection unit 53 with the threshold value Vth1. If the detection result of the detection unit 53 is greater than or equal to the threshold value Vth1, the changing unit 62 adopts a default value as the length of the target period. On the other hand, if the detection result of the detection unit 53 is less than the threshold value Vth1, the changing unit 62 extends the target period by a fixed time ΔT (see FIG. 3). The threshold value Vth1 is a voltage across both ends of the capacitive element C1 (drive voltage Vc1) when the capacitive element C1 is charged to such an extent that the operation of the load control device 1 can be ensured over at least a half cycle of the AC voltage Vac. . Specifically, a value obtained by adding a predetermined margin to the minimum value is used as the threshold value Vth1 so that the drive voltage Vc1 does not fall below a specified minimum value regardless of the dimming level. In FIG. 3, when the electrical energy accumulated in the capacitive element C1 is not insufficient, that is, the waveform of the drive voltage Vc1 that is the same as the drive voltage Vc1 shown in FIG.

  Here, during the operation of the load control device 1, the detection unit 53 always detects the magnitude of the electric energy accumulated in the capacitive element C <b> 1 (the magnitude of the drive voltage Vc <b> 1). When the detection result of the detection unit 53 falls below the threshold value Vth1 during the detection period, the changing unit 62 extends the target period from the first target period after the end of the detection period. The detection period here is a period in which the detection result of the detection unit 53 falls below the threshold value Vth1, and when the detection unit 53 always detects, the first period T1, the second period T2, the third period The period T3 and the fourth period T4. For example, as shown in FIG. 3, in the fourth period T4 of the second half cycle in the figure, when the detection result of the detection unit 53 falls below the threshold value Vth1, the second half cycle of the second half cycle The fourth period T4 is a detection period. Then, from the first target period after the end of this detection period (fourth period T4 of the second half cycle), that is, from the first period T1 of the third half cycle, the changing unit 62 (First period T1) is extended by a fixed time ΔT.

  In the present embodiment, once the target period is extended, the changing unit 62 continuously applies 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 cycle in FIG. 3 is set to a length obtained by adding a fixed time ΔT to the default value. In this case, the control unit 61 sets the first time point t1 at the time when the first detection signal ZC1 is generated, that is, the time point after a certain time ΔT after the time point t11 that is the detection timing of the phase (zero cross point) in the phase detection unit 3. Set. Then, at the first time point t1, the control unit 61 sets the first control signal Sb1 and the second control signal Sb2 to the “ON” signal, and the first power supply signal Ss1 to the “OFF” signal. That is, the first time point t1, which is the end point of the first period T1 (or the start point of the second period T2), is delayed by a certain time ΔT from the phase (zero cross point) detection timing in the phase detector 3. Thereafter, when the load control device 1 is turned off (the load 7 is turned off), the length of the target period (first period T1) is reset to a default value.

  As described above, when the electrical energy stored in the capacitive element C1 is insufficient, a decrease in electrical energy is detected by the detection unit 53, and the change unit 62 generates electrical energy in the power source unit 5. The target period (first period T1) for performing the operation is extended. Therefore, the electrical energy (driving power) generated by the power supply unit 5 in the target period increases by the extension of the target period, and as a result, the electric energy stored in the capacitive element C1 is insufficient. Is suppressed.

  In the case of this embodiment, since the half cycle of the AC voltage Vac is divided with priority given to securing the power supply from the AC power supply 8 to the power supply unit 5, the length of the second period T2 is input to the interface unit 4. It may not be specified depending on the dimming level. For example, even if the user operates the interface unit 4 so as to maximize the light output of the load 7, the extension of the first period T1 is prioritized, and the second dimming signal from the interface unit 4 is the second The start point of the period T2 may not be set.

  By the way, as a control method of the load control device 1, in addition to the antiphase control method (trailing edge method), the pair of input terminals 11 and 12 are electrically connected during the period from the middle of the half cycle of the AC voltage Vac to the zero cross point. There is a positive phase control method (leading edge method). In the anti-phase control method, power supply is started from the zero cross point to the load 7 including the LED element as the light source, so that the current waveform distortion at the start of power supply can be suppressed to a low level. Thereby, there is an advantage that the number of loads 7 (number of lamps) connectable to the load control device 1 is increased or generation of a beep can be suppressed.

  The load control device 1 of the present embodiment basically starts the power supply to the load 7 at the first time point t1 slightly delayed from the start point (zero cross point) t0 of the half cycle while adopting the antiphase control method. ing. Therefore, the current waveform distortion may be larger than that in the antiphase control method in which power supply to the load 7 is started at the zero cross point. However, since the absolute value of the AC voltage Vac at the first time point t1 is not so large, the influence of the current waveform distortion is so small that it can be ignored.

  Furthermore, in the load control device 1 of the present embodiment, the bidirectional switch 2 is turned on in the reverse direction during the period from the second time point t2 to the third time point t3 (third time period T3). 3 false detection can be reduced. 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, and as a result, a voltage having a polarity opposite to that of the AC voltage Vac (hereinafter referred to as “reverse polarity voltage”) is a pair. It may be applied to the input terminals 11 and 12. For example, in the case of a load 7 in which the voltage at both ends is difficult to decrease, such as a load 7 provided with a buffer capacitor having a relatively large capacity, such a reverse polarity voltage is likely to occur. When the reverse polarity voltage is generated, the phase detector 3 may erroneously detect the zero cross point at a place other than the zero cross point of the AC voltage Vac. There is also a load 7 in which a reverse polarity voltage is generated or not generated depending on the dimming level. With such a load 7, when the dimming level changes, the zero cross point changes suddenly. In the third period T3, since the bidirectional switch 2 is turned on in the reverse direction, the generation of such a reverse polarity voltage is suppressed, so that the erroneous detection of the phase detection unit 3 due to the reverse polarity voltage is prevented. Can be reduced.

(4) Modification (4.1) Modification 1
As illustrated in FIG. 4, the load control device 1 according to the first modification of the first embodiment detects the detection result when the change unit 62 detects that the detection result of the detection unit 53 is less than the first threshold value Vth1 as the threshold value. Until the second threshold value Vth2 is reached. That is, in the first modification of the first embodiment, the extension period of the target period by the changing unit 62 is not a fixed length (a constant time ΔT) but a variable length time determined according to the detection result of the detection unit 53. Hereinafter, the same configurations as those of the first embodiment are denoted by common reference numerals, and description thereof will be omitted as appropriate. In FIG. 4, when the electric energy accumulated in the capacitive element C1 is not insufficient, that is, the waveform of the drive voltage Vc1 that is the same as the drive voltage Vc1 shown in FIG.

  In the example of FIG. 4, since the detection result (drive voltage Vc1) of the detection unit 53 falls below the first threshold value Vth1 in the fourth period T4 of the second half cycle in the figure, the second half cycle has the second half cycle. The fourth period T4 is a detection period. Then, from the first target period after the end of this detection period (fourth period T4 of the second half cycle), that is, from the first period T1 of the third half cycle, the changing unit 62 (First period T1) is extended. At this time, the change unit 62 extends the target period until the detection result (drive voltage Vc1) of the detection unit 53 reaches the second threshold value Vth2. Therefore, the first period T1 after the third half cycle in FIG. 4 is set to a period extended from the default value. That is, the first time point t1, which is the end point of the first period T1 (or the start point of the second period T2), is delayed by a variable length of time from the phase (zero cross point) detection timing in the phase detector 3. . Thereafter, when the load control device 1 is turned off (the load 7 is turned off), the length of the target period (first period T1) is reset to a default value.

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

  According to the configuration of this modification, the extension time of the target period by the changing unit 62 is a variable length time determined according to the detection result of the detection unit 53, so that the target period is extended more than necessary or Insufficient time extension is unlikely to occur.

(4.2) Other Modifications Modifications of the first embodiment are listed below.

  The load control device 1 according to the first embodiment and the first modified example described above is not limited to the load 7 using an LED element as a light source, but is applied to a light source that is mounted with a capacitor input type circuit and has high impedance and is lit with a small current. Is possible. An example of this type of light source is an organic EL (Electroluminescence) element. Moreover, the load control apparatus 1 is applicable to the load 7 of various light sources, such as a discharge lamp, for example.

  Furthermore, the load 7 controlled by the load control device 1 is not limited to the illumination load, and may be, for example, a heater or a fan. When 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. When the load 7 is a fan, the load control device 1 constitutes a regulator that adjusts the rotational speed of the fan.

  In addition, the bidirectional switch 2 is not limited to the enhancement type n-channel MOSFET, and may be configured by, for example, two IGBTs (Insulated Gate Bipolar Transistors) 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 diode of the switching elements Q1 and Q2, but may be an external diode. The diode may be incorporated in the same package as each of the switch elements Q1, Q2. Furthermore, the bidirectional switch 2 may be a semiconductor device having a double gate (dual gate) structure using a wide band gap semiconductor material such as GaN (gallium nitride). According to this configuration, the conduction loss of the bidirectional switch 2 can be reduced.

  Further, the switching power supply 52 may generate the control voltage Vc2 directly from the AC voltage Vac subjected to full-wave rectification without using the dropper power supply 51. Furthermore, the control unit 61 may switch whether or not to perform a generation operation for generating electrical energy (control power) accumulated in the capacitive element C2 by controlling the switching power supply 52. In this case, the detection unit 53 may detect the magnitude of electric energy (control power) accumulated in the capacitive element C2 of the switching power supply 52. For example, the detection unit 53 detects the magnitude of the control voltage Vc2 that is 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 is less than a predetermined threshold value.

  Further, in the control of the bidirectional switch 2, it is possible to control to “forward on state” instead of “bidirectional on state”, and conversely, “bidirectional on” instead of “forward on state”. It is also possible to control the state. Further, it is possible to control the “reverse direction ON state” instead of the “bidirectional off state”, and it is possible to control the “bidirectional off state” instead of the “reverse direction ON state”. That is, it is sufficient that the bidirectional switch 2 does not change the conductive state or the non-conductive state.

  Further, the control method of the bidirectional switch 2 by the control circuit 6 is not limited to the above-described example. For example, the first control signal Sb1 and the second control signal Sb2 are alternately turned on in the same cycle as the AC voltage Vac. It may be a method. In this case, the bidirectional switch 2 becomes conductive during the period when the switch element on the high potential side of the AC voltage Vac is on among the switch elements Q1 and Q2. That is, in this modification, so-called reverse phase control is realized in which the pair of input terminals 11 and 12 are electrically connected during a period from the zero cross point of the AC voltage Vac to the middle of the half cycle. In this case, the conduction 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.

  Furthermore, the control method of the control unit 61 of the load control device 1 may be a universal control method that can support both the positive phase control method and the reverse phase control method.

  Further, the control unit 61 is not limited to the configuration for switching whether or not to cause the power supply unit 5 to perform the generation operation by the first power supply signal Ss1. For example, the control unit 61 shuts off a switch provided between at least one of the pair of input terminals 11 and 12 and the power source unit 5 (dropper power source 51), and electrically connects the power source unit 5 from the AC power source 8. The configuration may be such that the generation operation is stopped by disconnecting.

  In addition, the detection unit 53 is not limited to the configuration that always detects the magnitude of the electric energy accumulated in the capacitive element C1 (the magnitude of the drive voltage Vc1), but a part of the half cycle of the AC voltage Vac. You may detect only in a period. For example, the detection unit 53 may detect the magnitude of the electrical energy accumulated in the capacitive element C1 only in the fourth period T4.

  Furthermore, the target period extended by the change part 62 should just consist of at least one period of 1st period T1 and 4th period T4, and is not restricted to 1st period T1. That is, the target period may be the fourth period T4, or both the first period T1 and the fourth period T4. When the fourth period T4 is included in the target period, the changing unit 62 extends the target period (fourth period T4) by advancing the start point (time point t3) of the fourth period T4. . For example, when the detection result of the detection unit 53 falls below the threshold value Vth1 in the first period T1, the changing unit 62 may extend the fourth period in the same half cycle as the first period T1. .

  Further, when the detection result of the detection unit 53 falls below the threshold value Vth1 in the detection period, the changing unit 62 is not limited to the configuration in which the target period is extended from the first target period after the end of the detection period. You may extend from the 2nd time target period after the end of this detection period. Furthermore, in the target period (first period T1), when the detection result of the detection unit 53 falls below the threshold value Vth1, the changing unit 62 extends the target period from the target period (first period T1). Also good.

  Further, once the target period is extended, the changing unit 62 is not limited to the configuration in which the extended target period is continuously applied until the load control device 1 is turned off. For example, the change unit 62 extends for each target period. It may be determined whether or not. Thereby, in the case where the electrical energy stored in the capacitive element C1 is temporarily insufficient, if the electrical energy stored in the capacitive element C1 returns to a normal value, the length of the target period is increased. Is reset to the default value.

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

  Further, the switch drive unit 9 is not an essential component of the load control device 1 and may be omitted as appropriate. When the switch driving unit 9 is omitted, the control circuit 6 drives the bidirectional switch 2 directly. When the switch drive unit 9 is omitted, the dropper power supply 51 may be omitted.

  Further, the first time point t1 is not limited to the time point when the first detection signal ZC1 or the second detection signal ZC2 is generated, but a fixed delay time (for example, 300 [μs] from the time point when the first detection signal ZC1 or the second detection signal ZC2 is generated. ]) May have elapsed. The delay time is not limited to 300 [μs], but is appropriately set in the range of 0 [μs] to 500 [μs].

  Further, the third time point t3 only needs to be before the end point (zero cross point) t4 of the half cycle, and the length from the third time point t3 to the end point t4 of the half cycle can be set as appropriate. For example, when the time length from the first time point t1 to the third time point t3 is shorter than the half cycle by a certain specified time, the specified time is not limited to 300 [μs], but is 100 [μs] to 500 [μs]. It is set as appropriate within the range.

  The diodes D1 and D2 in the first embodiment are not essential to the load control device 1, and the diodes D1 and D2 may be omitted as appropriate.

  Moreover, although Embodiment 1 demonstrated the case where the load control apparatus 1 was a two-wire type, not only this structure but the load control apparatus 1 is what is called a three-way switch which can connect three electric wires, for example, Or what is called a four-way switch etc. which can connect four electric wires may be sufficient. When the load control device 1 constitutes a three-way switch, by combining the two load control devices 1, the state of energization of the load 7 can be changed, for example, at two locations of the upper floor portion and the lower floor portion of the stairs in the building. It is possible to switch.

  Further, in the comparison between two values such as the AC voltage Vac and the specified value Vzc, “more than” includes both the case where the two values are equal and the case where one of the two values exceeds the other. However, the present invention is not limited to this, and “more than” here may be synonymous with “greater than” including only when one of the binary values exceeds the other. In other words, whether or not the case where the two values are equal can be arbitrarily changed depending on the setting of the specified value Vzc or the like, so there is no technical difference between “greater than” or “greater than”. Similarly, “less than” may be synonymous with “below”.

(Embodiment 2)
As shown in FIG. 5, the load control device 1 </ b> A according to the present embodiment is different from the load control device 1 according to the first embodiment in that it further includes a stop unit 63 that stops the conversion operation of the switching power supply 52. Hereinafter, the same configurations as those of the first embodiment are denoted by common reference numerals, and description thereof is omitted as appropriate.

  The stop unit 63 electrically disconnects the switching power supply 52 from the AC power supply 8 or stops the conversion operation of the switching power supply 52 during the exclusion period. The “exclusion period” here is a period including the detection timing at which the phase detection unit 3 detects the phase. When the phase detection unit 3 detects the zero cross point, the exclusion period is a period including the zero cross point. is there. In the present embodiment, the stop unit 63 is included in the control circuit 6A. The stopping unit 63 increases the input impedance of the dropper power supply 51 by stopping the operation of the first circuit 511 with the first power supply signal Ss1, for example, and stops the generation operation of the dropper power supply 51. When the generation operation of the dropper power supply 51 is stopped by the first power supply signal Ss1, the switching power supply 52 is electrically disconnected from the AC power supply 8.

  While the switching power supply 52 is performing the conversion operation, the impedance of the power supply unit 5 fluctuates due to switching of the switching element, and a pulsation (ripple) occurs in the current flowing from the AC power supply 8 to the power supply unit 5. is there. That is, a switching type DC-DC converter such as the switching power source 52 is more efficient than a series regulator type power supply circuit, but is likely to be a source of noise. When pulsation (ripple) occurs in the current flowing from the AC power supply 8 to the power supply unit 5, the phase detection unit 3 may have a reduced accuracy in detecting the phase of the AC voltage Vac. That is, since the phase detector 3 monitors a relatively small voltage of about several [V] in order to detect the zero cross point of the AC voltage Vac, the current is slightly affected by the noise generated by the switching power supply 52. Even if it fluctuates, the phase detection accuracy may decrease.

  Therefore, in the load control device 1A according to the present embodiment, at the stop unit 63, as illustrated in FIG. 52 is electrically disconnected from the AC power supply 8. In FIG. 6, AC voltage “Vac”, first detection signal “ZC1”, second detection signal “ZC2”, first control signal “Sb1”, second control signal “Sb2”, first power supply signal “Ss1”, And the drive voltage “Vc1”.

  That is, the switching power supply 52 is not always electrically connected to the AC power supply 8, but is electrically disconnected from the AC power supply 8 during the exclusion period T0. As shown in FIG. 6, the exclusion period T0 includes the detection timing of the phase (zero cross point) in the phase detector 3, that is, the time point t11 that is the generation time point of the first detection signal ZC1 or the second detection signal ZC2. It is a specified period. In the present embodiment, the start point t21 of the exclusion period T0 is set within the fourth period T4 (period t3 to t4), and the end point t22 of the exclusion period T0 is within the first period T1 (period t0 to t1). Is set. That is, the exclusion period T0 is defined to extend over two periods, 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 (period t11 to t1) after the phase detection timing (time point t11) in the phase detection unit 3 in the first period T1. Thereby, the phase detection timing (time point t11) in the phase detector 3 is included in the exclusion period T0.

  Specifically, the stopping unit 63 increases the input impedance of the dropper power supply 51 by stopping the operation of the first circuit 511 with the first power supply signal Ss1 in the exclusion period T0 in the half cycle of the AC voltage Vac. Then, the generation operation of the dropper power supply 51 is stopped. The switching power supply 52 is electrically disconnected from the AC power supply 8 while the generation operation of the dropper power supply 51 is stopped by the first power supply signal Ss1. That is, the stop unit 63 extends from the start point t21 set in the fourth period T4 (period t3 to t4) to the end point t22 set in the first period T1 (period t0 to t1). However, the first power supply signal Ss1 is set as an “OFF” signal. Thereby, in the exclusion period T0 (period t21 to t22) in the fourth period T4 and the first period T1, the generation operation of the dropper power supply 51 is stopped, and the switching power supply 52 is electrically connected from the AC power supply 8. Separated.

  Thereby, in the exclusion period T0, the fluctuation of the impedance of the power supply unit 5 due to the conversion operation of the switching power supply 52 is suppressed, and the pulsation (ripple) hardly occurs in the current flowing from the AC power supply 8 to the power supply unit 5. As a result, at the detection timing (time point t11) included in the exclusion period T0, a decrease in phase detection accuracy by the phase detection unit 3 is suppressed.

  The end point t22 of the exclusion period T0 may coincide with the phase detection timing (time point t11) in the phase detection unit 3. That is, since the phase detection unit 3 has detected the phase, the conversion operation of the switching power supply 52 does not affect the phase detection accuracy of the phase detection unit 3. The exclusion period T0 may end at the timing.

  Here, the switching power supply 52 does not stop the conversion operation immediately when it is electrically disconnected from the AC power supply 8, but is stored in the capacitive element C1 while the first power supply signal Ss1 is the “ON” signal. The conversion operation is continued by the electric charge. That is, if sufficient electric energy (drive power) is accumulated in the capacitive element C1, the switching power supply 52 can continue the conversion operation even in the exclusion period T0.

  Further, in the present embodiment, the changing unit 62 is configured to extend the target period by the shortened time by shortening the exclusion period T0 by the shortened time. That is, in the load control device 1A according to the present embodiment, as shown in FIG. 7, the change unit 62 shortens the exclusion period T0 according to the detection result of the detection unit 53, and only the shortened time of the exclusion period T0. Extend the target period. In the example of FIG. 7, the changing unit 62 shortens the exclusion period T0 by the shortening time corresponding to the entire exclusion period T0 by eliminating the exclusion period T0. In the example of FIG. 7, both the fourth period T4 and the first period T1 are extended by eliminating the exclusion period T0 across the two periods of the fourth period T4 and the first period T1. Therefore, both the fourth period T4 and the first period T1 are the target period. FIG. 7 is a timing chart similar to FIG. 6 in the case where the electrical energy accumulated in the capacitive element C1 is insufficient due to the load 7.

  In other words, the changing unit 62 shortens the period (exclusion period T0) in which the generation operation of the dropper power supply 51 is stopped in the target period by shortening the exclusion period T0 included in the target period. As a result, at least a part of the exclusion period T0 in which the generation operation of the dropper power supply 51 is originally stopped is transferred to the target period in which the dropper power supply 51 is generated, and the target period is substantially extended.

  Specifically, the change unit 62 shortens the exclusion period T0 when the detection result of the detection unit 53 is less than a predetermined threshold value Vth1 (see FIG. 7), and reduces the exclusion period T0 by the shortened time of the exclusion period T0. Both the first period T1 and the fourth period T4) are extended. For example, as shown in FIG. 7, in the third period T3 of the second half cycle in the figure, when the detection result of the detection unit 53 falls below the threshold value Vth1, the second half cycle of the second half cycle The third period T3 is a detection period. Then, from the first target period after the end of the detection period (the third period T3 of the second half cycle), that is, the fourth period T4 of the second half period, the changing unit 62 performs the exclusion period. Shorten T0 and extend the target period.

  As described above, when the electrical energy stored in the capacitive element C1 is insufficient, a decrease in electrical energy is detected by the detection unit 53, and the change unit 62 generates electrical energy in the power source unit 5. The target period (first period T1 and fourth period T4) for performing the operation is extended. Therefore, the electrical energy (driving power) generated by the power supply unit 5 in the target period increases by the extension of the target period, and as a result, the electric energy stored in the capacitive element C1 is insufficient. Is suppressed.

  However, the changing unit 62 is not limited to the configuration in which the exclusion period T0 is shortened by eliminating the exclusion period T0. For example, the changing unit 62 shortens the length of the exclusion period T0 in half, or the length of the exclusion period T0 for a certain time. The structure etc. which shorten only by the part may be sufficient.

  As a modification of the second embodiment, the stopping unit 63 may stop the conversion operation of the switching power supply 52 instead of electrically disconnecting the switching power supply 52 from the AC power supply 8 during the exclusion period T0. Specifically, as illustrated in FIG. 8, the stop unit 63 stops the conversion operation of the switching power supply 52 by stopping the operation of the second circuit 521 with the second power supply signal Ss2. In FIG. 8, AC voltage “Vac”, first detection signal “ZC1”, second detection signal “ZC2”, first control signal “Sb1”, second control signal “Sb2”, first power supply signal “Ss1”, The second power supply signal “Ss2” and the drive voltage “Vc1” are shown.

  Even in this case, the pulsation of the current flowing from the AC power supply 8 to the power supply unit 5 due to the switching of the switching element of the switching power supply 52 is suppressed during the exclusion period T0. Since the exclusion period T0 is a period sufficiently shorter than the half cycle of the AC voltage Vac, the operation of the control circuit 6 and the like is maintained by the electric energy (control power) accumulated in the capacitive element C2 of the switching power supply 52. Is done. However, in this case, even if the exclusion period T0 is shortened by the shortening time, the target period is not extended by the shortening time.

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

(Summary)
As described above, the load control device 1 according to the first aspect includes the bidirectional switch 2, the phase detection unit 3, the power supply unit 5, the detection unit 53, the control unit 61, the change unit 62, Is provided. The bidirectional switch 2 is electrically connected in series with the load 7 with respect to the AC power supply 8 and controls the phase of the AC voltage Vac supplied to the load 7. The phase detector 3 detects the phase of the AC voltage Vac. The power supply unit 5 includes a capacitive element C <b> 1 that stores electrical energy, is electrically connected in parallel to the bidirectional switch 2, and performs a generation operation that generates electrical energy using power supplied from the AC power supply 8. The detection part 53 detects the magnitude | size of the electrical energy accumulate | stored in the capacitive element C1. The control unit 61 is supplied with electric energy from the capacitive element C <b> 1 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 detector 3, the controller 61 determines a half cycle consisting of two consecutive zero-cross points of the AC voltage Vac as the first period T 1, the second period T 2, and the third period. Into a period T3 and a fourth period T4. In the first period T1 and the fourth period T4, the control unit 61 turns off the bidirectional switch 2 and causes the power supply unit 5 to perform a generation operation. In the second period T2, the control unit 61 turns on the bidirectional switch 2 and stops the generation operation of the power supply unit 5. In the third period T3, the control unit 61 turns off the bidirectional switch 2 and stops the generation operation of the power supply unit 5. The changing unit 62 extends the target period including at least one of the first period T1 and the fourth period T4 when the detection result of the detection unit 53 is less than the threshold value Vth1.

  According to this configuration, when the electrical energy stored in the capacitive element C1 is insufficient, a decrease in electrical energy is detected by the detection unit 53, and the change unit 62 causes the power source unit 5 to The target period for performing the generating operation is extended. Therefore, the electric energy generated by the power supply unit 5 in the target period is increased by the extension of the target period, and as a result, the shortage of the electric energy accumulated in the capacitive element C1 is suppressed. . In other words, according to the load control device 1, the shortage of electric energy accumulated in the capacitive element C 1 due to the load 7 is less likely to occur, and the load control device 1 or the load 7 due to the shortage of electric energy is caused. The occurrence of abnormal operation can be suppressed. Therefore, according to the load control device 1, there is an advantage that it is possible to deal with more types of loads 7.

  In the first aspect, the load control device 1 according to the second aspect further includes an interface unit 4 to which an input level defining the end point (second time point t2) of the second period T2 in the half cycle is input. It is preferable. According to this configuration, the length of the on time during which the bidirectional switch 2 is in a conductive state can be adjusted according to the input level to the interface unit 4. However, this configuration is not essential for the load control device 1, and the interface unit 4 may be omitted as appropriate.

  In the load control device 1 according to the third aspect, in the first or second aspect, the change unit 62 starts from the first target period after the end of the detection period when the detection result falls below the threshold value Vth1 in the detection period. It is preferable to be configured to extend the target period. The detection period includes any one of the first period T1, the second period T2, the third period T3, and the fourth period T4. According to this configuration, since the target period is extended immediately after the detection result of the detection unit 53 falls below the threshold value Vth1, it is easy to avoid a situation where the electrical energy accumulated in the capacitive element C1 is insufficient.

  In any one of the first to third aspects, the load control device 1 according to the fourth aspect is configured so that the changing unit 62 extends the target period by a certain time ΔT when the detection result is less than the threshold value Vth1. It is preferable to be configured. According to this configuration, the process for extending the target period is simplified. However, this configuration is not essential for the load control device 1, and the extension time of the target period may be variable.

  In any one of the first to third aspects, the load control device 1 according to the fifth aspect is such that the change unit 62 determines that the detection result is the second when the detection result is less than the first threshold value Vth1 as the threshold value Vth1. It is preferable that the target period is extended until the threshold value Vth2 is reached. According to this configuration, when the detection result of the detection unit 53 falls below the first threshold value Vth1, the target period is extended until the electrical energy accumulated in the capacitive element C1 is recovered to some extent. It becomes easy to avoid a situation where the electric energy stored in C1 is insufficient.

  In the load control device 1 according to the sixth aspect, in any one of the first to fifth aspects, the power supply unit 5 preferably includes the switching power supply 52. The switching power supply 52 performs a conversion operation for converting the DC voltage (drive voltage Vc1) supplied from the capacitive element C1 into the control voltage Vc2 by the switching operation of the switching element. In this case, it is preferable that the load control device 1 further includes a stop unit 63. The stop unit 63 electrically disconnects the switching power supply 52 from the AC power supply 8 or stops the conversion operation of the switching power supply 52 during the exclusion period T0 including the detection timing at which 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. According to this configuration, at the detection timing when the phase detection unit 3 detects the phase, pulsation (ripple) generated in the current flowing from the AC power supply 8 to the power supply unit 5 due to switching of the switching element of the switching power supply 52. Is suppressed. Therefore, a decrease in the phase detection accuracy in the phase detector 3 due to the influence of noise generated by the switching power supply 52 is suppressed. If the detection accuracy of the phase of the AC voltage Vac in the phase detector 3 is improved, normal operation of the load control device 1 or the load 7 is easily maintained. However, this configuration is not essential for the load control device 1, and the stop unit 63 may be omitted as appropriate.

  In the sixth aspect, the load control device 1 according to the seventh aspect is configured such that the changing unit 62 extends the target period by the shortened time by shortening the exclusion period T0 by the shortened time. Preferably it is. According to this configuration, since at least a part of the exclusion period T0 in which the generation operation of the dropper power supply 51 is stopped is transferred to the target period in which the dropper power supply 51 is generated, the start point and the end point of the target period are changed. The target period can be extended.

DESCRIPTION OF SYMBOLS 1,1A Load control apparatus 2 Bidirectional switch 3 Phase detection part 4 Interface part 5 Power supply part 7 Load 8 AC power supply 52 Switching power supply 53 Detection part 61 Control part 62 Change part 63 Stop part C1 Capacitive element T0 Exclusion period T1 1st Period T2 second period T3 third period T4 fourth period Vac AC voltage Vc1 Drive voltage (DC voltage)
Vc2 control voltage Vth1 (first) threshold Vth2 second threshold

Claims (7)

A bidirectional switch that is electrically connected in series with a load with respect to an AC power source, and phase-controls the AC voltage supplied to the load;
A phase detector for detecting the phase of the AC voltage;
A power supply unit having a capacitive element for storing electrical energy, electrically connected in parallel with the bidirectional switch, and performing a generating operation for generating the electrical energy by power supplied from the AC power supply;
A detection unit for detecting the magnitude of the electric energy accumulated in the capacitive element;
The electric energy is supplied from the capacitive element of the power supply unit to control the bidirectional switch and the power supply unit, and based on the phase detected by the phase detection unit, two consecutive zero crossings of the AC voltage Dividing a half-cycle consisting of periods between points into a first period, a second period, a third period, and a fourth period,
In the first period and the fourth period, the bidirectional switch is turned off, and the power supply unit performs the generation operation.
In the second period, the bidirectional switch is turned on, the generation operation of the power supply unit is stopped,
In the third period, the bidirectional switch is turned off, and the generation unit of the power supply unit is stopped, a control unit;
When the detection result of the detection unit is less than a threshold, a change unit that extends a target period consisting of at least one of the first period and the fourth period;
A load control device comprising: The load control device according to claim 1, further comprising an interface unit to which an input level defining an end point of the second period in the half cycle is input. In the detection period consisting of any one of the first period, the second period, the third period, and the fourth period, the change unit, when the detection result falls below the threshold, The load control device according to claim 1, wherein the target period is extended from the first target period after the end of the detection period. The load control device according to any one of claims 1 to 3, wherein the changing unit is configured to extend the target period by a predetermined time when the detection result is less than the threshold value. The said change part is comprised so that the said target period may be extended until the said detection result reaches a 2nd threshold value, when the said detection result is less than the 1st threshold value as the said threshold value. The load control device according to any one of the above. The power supply unit includes a switching power supply that performs a conversion operation of converting a DC voltage supplied from the capacitive element into a control voltage by a switching operation of the switching element,
In the exclusion period including the detection timing at which the phase detection unit detects the phase, the switching power supply is electrically disconnected from the AC power supply, or further includes a stop unit that stops the conversion operation of the switching power supply,
The load control device according to claim 1, wherein the exclusion period is set to at least one of the first period and the fourth period. The load control device according to claim 6, wherein the changing unit is configured to extend the target period by the shortened time by shortening the exclusion period by a shortened time.

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