JPH0332320A - Ac control circuit - Google Patents

Abstract

PURPOSE:To perform supply power regulating operation smoothly by discharging a capacitor at the end of half wave of AC source voltage thereby eliminating hysteresis between the resistance of a variable resistor and supply power. CONSTITUTION:Time constant of a resistor R2 and a capacitor C2 is set such that a three terminal switching element T3 is conducted at the end of each half wave of AC source voltage E. A capacitor C2 is charged through the resistor R2 for every half wave of the AC source E voltage, and the three terminal switching element T3 is conducted at the end of the half wave of AC source E voltage thus discharging a capacitor C1. Consequently, the capacitor C1 is discharged at the end of each half wave even if a variable resistor VR1 has resistance high enough to prevent conduction of a trigger element T2 between half waves and thereby no charge is left in the capacitor C1.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to two-way silisks or two anti-parallel connected
The present invention relates to an AC control circuit that uses reverse-blocking syrisks or the like as a phase control element to supply power from an AC power source to a load on the phase side.

[Traditional techniques]

FIG. 4 shows a conventional general AC control circuit.

Figure 4 ↓ Here, E is an AC power supply, LD is a load such as an incandescent lamp, T1 is a phase control element such as a bidirectional zyristor, and 'I゛2 is a trigger element such as a bidirectional trigger diode. . VR, is a variable resistor, C is a capacitor, and these determine the trigger timing of the phase control element '1'1. R4 is provided for protection when the resistance value of the variable resistor VR becomes zero, and the maximum load power is determined by the resistance value of the resistor R4.

As is well known, in this AC control circuit, when the voltage of the capacitor C1 charged through the resistor R2 and the variable resistor VR exceeds the breakover voltage VRO of the trigger element 'F2, the trigger element T2 becomes conductive. Phase control element] 1 is made conductive. This operation is a half wave of the voltage of AC power supply E! By repeating IU and changing the resistance value of the variable resistor VRl and changing the trigger timing of the phase control element T1, the power supplied to the load LD can be controlled.

In this case, for example, the brightness of an incandescent lamp may be adjusted.

FIG. 5 is a waveform diagram of each part in FIG. 4 when the resistance value of variable resistor VRl is increased, and FIG. 6 is a waveform diagram of each part in FIG. 4 when the resistance value of variable resistor VRl is decreased. In each figure, ta+ is the load current 'L l), and (b) is the voltage of the capacitor C1. , is shown.

[Problem to be solved by the invention]

In the AC control circuit of FIG. 4, when the resistance value of the variable resistor VRl is further increased, the voltage of the capacitor "C1 does not reach the breakover voltage VBO of the trigger element T2 during the half-wave of the voltage of the AC power supply E," The trigger element T2 is not conducting, that is, the phase control element T1 is completely cut off. In this state, a charge remains in the capacitor C4 at the end of each cycle jUJ of the voltage of the AC power supply E, and the capacitor C
A voltage V remains at 1. This voltage Vx has a polarity opposite to that of the voltage in the next half wave, and charging of the capacitor C1 starts after the residual charge of the capacitor C1 is discharged.

FIG. 7 is a waveform diagram of each part in FIG. 4 when the resistance value of the variable resistor VRl is sufficiently high and the trigger element T2 is not conductive.
The waveform of the same part as the figure is shown.

As described above, when charge remains in the capacitor C7, when the resistance value of the variable resistor VRl is decreased to start supplying power to the load LD, the variable resistor V
The resistance value of Rl must be made small. Therefore, when starting power supply to the load LD by decreasing the resistance value of the variable resistor VRl, the resistance value at the start of power supply and the variable resistor V
When the resistance value of Rl is increased to stop the power supply to the load LD, a hysteresis phenomenon occurs in which the resistance value is different from the resistance value when the power supply is stopped. As a result, the variable resistance V when power supply starts
Rl knob position and variable resistance VR when power supply stops
The position of the l knob is no longer the same.

Figure 8 shows the relationship (hysteresis characteristics) between the resistance value of the variable resistor VRl and the power supplied to the load LD, Figure 9 shows the slide type variable resistor 1, and Figure 10 shows the rotary type variable resistor 1. Resistor 2 is shown. The symbols A-D in FIG. 8 are the positions A-D of the knob 1a of the variable resistor 1 in FIG.
Position A- of the mark 2b of the knob 2a of the variable resistor 2 in Figure 0
Each corresponds to D.

In the variable resistor 1.2 of FIGS. 9 and 10, move the knobs Ia and 2a from the D position via the C and A positions to the B position, and from the subsequent position to the A and C positions. When returning to the position D via the position D, the power supplied to the load LD changes as shown in FIG. 8 in accordance with the change in resistance value at that time. Therefore, in order to start power supply to load LD, it is necessary to move knobs la and 2a to position A, and to stop power supply to load LD, it is necessary to return knobs la and 2a to position C. As mentioned above, in the conventional AC control circuit, there is a hysteresis characteristic between the resistance value of the variable resistor VRl and the power supplied to the load LD, so it is not possible to smoothly adjust the supplied power. There was a problem.

An object of the present invention is to provide an AC control circuit that can smoothly adjust power supply.

[Means to solve the problem]

The AC control circuit of the present invention includes a phase control element inserted in the power supply path from the AC power supply to the load, and a series circuit of a variable resistor and a first capacitor supplied with power from the AC power supply, and a first capacitor.
A trigger element is provided that conducts when the voltage across the capacitor exceeds a predetermined value and triggers the phase control element. and a three-terminal switching element that is connected and becomes conductive when the voltage across the second capacitor exceeds a predetermined value.

In this case, 11 (resistance t, , Il of the series l811 circuit of the first and second capacitors, 'I constant is set.

[For production]

According to the configuration of the present invention, the three-terminal switching element becomes conductive at the end of each half-wave of the voltage of the AC power supply, and the first capacitor is forcibly discharged for a moment. As a result, if the resistance value of the variable resistor is large enough that the trigger element does not conduct during the half-wave (even if there is, the first ′,
The residual W1 charge of non-den 1) can be made zero, and the hysteresis characteristic between the resistance value of the variable resistor and the power supplied to the load caused by the residual charge can be eliminated.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an AC 1++I 1ff of the embodiment of this invention.
ll l! +] circuit diagram is shown. This AC control circuit connects a series circuit of resistors R2, 1, and 1JC2 to a series circuit of a variable resistor VR and a capacitor C1 in an if<column, and connects, for example, SBS (or a necessary potential A bidirectional three-terminal switching element 'I3' consisting of an equivalent element externally connected with a resistor and a capacitor) is connected in parallel to the capacitor C1, and the voltage of the capacitor 'IJC2 is transferred to the three-terminal switching element 'I3'. In addition to the gate.

In this case, the time constant of resistor R2 and capacitor C2 is changed to the three-terminal switching element 7 at the end of each half-wave of the voltage of AC power supply E.
-T3 is set to II.

The other configurations are the same as the AC control circuit shown in FIG.

In this AC control circuit, every half-wave of the AC power source ■Σ, the capacitor is charged through C2 or the resistor R2, and at the end of the half-wave of the voltage of the AC power source E, the three-terminal switching element 'l3 becomes conductive and the capacitor is charged. →The charge of JC will be released. As a result, by making the variable resistor VR, sufficiently large, 1-
Even in a state in which the Liga element 7-T2 does not conduct at all during a half-wave, that is, in a state in which power is not supplied to the load LD, the charge in the capacitor C1 is discharged at the end of each half-wave, and the charge remaining in the capacitor C1 is Il? ! No charge is generated. Therefore, the resistance value of the variable resistor V R and the load L + that could be carried in the conventional example are
3-\'s Ij (the problem of hysteresis characteristics between the supply force and the force is to be seen. Therefore, the variable resistance V R
An operation for adjusting the power supplied to the load 1-1:) can be performed in circle 711 by adjusting the load 1-1:).

Note that when the resistance value of the variable resistor VR is small and the trigger element '1'2 becomes conductive to trigger the phase control element T1 by the end of the half-wave of the voltage of the AC power supply E, the operation is as shown in the conventional method shown in FIG. This is similar to the example, and in this case as well, the three-terminal switching element T3 becomes conductive once at the end of the half-wave of the voltage of the AC power source E.

FIG. 2 shows the relationship (hysteresis-free characteristic) between the resistance value of the variable resistor VR and the power supplied to the load LD-.

Figure 3 is a waveform diagram when the resistance value of variable +i (anti-VR) is made sufficiently large so that the trigger elements '1 and 2 are not conductive.
(al is the load current 11-D, (b) is the capacitor C
The voltage ■C1 is shown. From this figure, it is clear that at the end of the half-wave of the voltage of the AC power supply E, the charge of the condenser C1 is discharged, and the voltage vcl of the capacitor C1 becomes zero.

Note that in the embodiment described in L, a bidirectional sirisk, so-called [・Liasoku] was used as the m-phase control element T, but 2 (I?ll sirisks connected in antiparallel) may also be used. For the elements '1 and 2, any voltage responsive switching element other than those mentioned in the embodiments can be used.

〔Effect of the invention〕

According to the AC control circuit of the present invention, the second resistor, the second capacitor C1, and the three-terminal switching element are provided, and the electric charge of the first converter is discharged at the end of the half-wave of the voltage of the AC power source. Therefore, it is possible to eliminate the hysteresis characteristic between the resistance value of the variable resistor and the power supplied to fl and Q, making it possible to smoothly adjust the variable resistor ↓ and adjust the power supplied to the load m. It can be carried out.

[Brief explanation of drawings]

1151 is a circuit diagram of an AC control circuit according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing the relationship between the resistance value of the variable resistor and the power supplied to the load in the circuit of FIG. 1, and FIG. Waveform diagrams of various parts of the circuit in Figure 1 when the resistance value of the variable resistor is set sufficiently large, Figure 4 is a circuit diagram of a conventional AC control circuit, and Figure 5 is a diagram of the resistance value of the variable resistor set to a sufficiently large value. Figure 6 is a waveform diagram of each part in Figure 4 when the resistance value of the variable resistor is set small, Figure 7 is a waveform diagram of each part in Figure 4 when the resistance value of the variable resistor is set sufficiently large. Figure 8 is a characteristic diagram showing the relationship between the resistance value of the variable resistor and the power supplied to the load in the circuit of Figure 4, and Figure 9 is a diagram of the waveforms of each part of the circuit in Figure 4. Perspective view of variable resistor, 1st
FIG. 0 is a perspective view of the external appearance of a rotary variable resistor. E...AC power supply, L D...Load, T1...Phase control element, T2...1 to trigger element, T3...3 terminal switching element, VR,...Variable resistor, R2...・・・
Resistance, C1゜C2... Capacitor 1 - Dawatari Denrei - Load 1 - It 4 Hair iF 5 Suap So 3 4 - Trif/Suyu 1 -- 3) Switch number 1 --- Variable resistance q Figure 4 Figure Figure Figure Figure Large □ Small J Mr. IN (! '-1 shot) 1° Incident display flat bottom 1 year 4)' Patent application No. 167721, Name of invention Exchange 1111 Digit mouth circuit 3° Who makes the correction! Use L1 Which relationship 1jj E of the applicant's amendment order

Claims (1)

[Claims] A phase control element inserted in a power supply path from an AC power supply to a load, a variable resistor supplied with power from the AC power supply, and a first
a series circuit of capacitors, a trigger element that becomes conductive to trigger the phase control element when the voltage across the first capacitor exceeds a predetermined value, a resistor supplied with power from the AC power source, and a second capacitor. and a three-terminal switching element connected in parallel to the first capacitor and having the voltage of the second capacitor applied to its gate, the three-terminal switching element controlling each half-wave of the voltage of the AC power supply. An AC control circuit in which a time constant of the series circuit of the resistor and the second capacitor is set so that conduction occurs at the terminal end.