JPH03210610A - Phase control circuit for ac power - Google Patents

Abstract

PURPOSE:To eliminate a hysteresis phenomenon by connecting two diodes in series and in the same direction between the joints of a variable resistance and a capacitor and also connecting a trigger element between the joint set between both diodes and a semiconductor switching element. CONSTITUTION:A controlling phase circuit consists of the interlocking variable resistances VR1 and VR2 and capacitors C1 and C2. Then the reverse remaining voltage is produced at the terminals of capacitors C1 and C2 by the diodes D1 and D2. The trigger voltage is taken out at the middle point between both diodes D1 and D2 and applied to the gate of a triac serving as a semiconductor switching element of S1 via a diac serving as a trigger element of S2. Thus the trigger current of a positive liquid which controls the positive liquid of the power voltage flows in the direction C1 D1 S2. Meanwhile the trigger current of a negative liquid which controls the negative liquid flows in the direction C2 S2 D2 respectively. Thus no hysteresis phenomenon occurs at all.

Description

[Detailed Description of the Invention] 1. Field of Industrial Application] The present invention is directed to AC power phase control t! This concerns l#I.

[Traditional technique brass] Figure 1 shows the basics of AC power phase control circuit v#! It is a country.

The phase angle of the terminal voltage of the capacitor CI and the phase angle of the power supply voltage applied to the semiconductor switching element change, and the phase angle of the terminal voltage of the capacitor 〇1 changes depending on the resistance value of the -1 variable resistor Vl. In this way, The output is determined by the relationship between the controlled terminal voltage of the capacitor C1 (trigger voltage) and the phase angle of the voltage applied to the semiconductor switching element.However, the controlled phase angle is different before and after the trigger element is activated. This is because the initial conditions for charging the capacitor CI differ depending on the discharge.

This phenomenon occurs in the low control range of power.

This results in an extremely hysteresis phenomenon. Conventionally, auxiliary charging or active discharging measures have been taken as mitigation measures.

[Interlayer point to be solved by the invention] The hysteresis phenomenon is the discharge of the phase-path capacitor II.
This is because the initial conditions will be different later on, as mentioned above, and this is because the trigger voltage of the member is carried by one capacitor.

Means and action for solving problem E] The second factor is the circuit R diagram which is the basis of the present invention. The two sets of phase circuits R, C1 and Rλ, Cs are connected through one diode in the direction of the diagram between the respective RCC contacts. No more! ! When the alternating current voltage is applied to 11 as I:p7jl, a residual voltage ΔV in the opposite direction is generated between CI- and CI- with the applied voltage being 0. The inventors of the present application focused on this residual voltage, and controlled the stop terminal voltage of C1, which causes a residual voltage of -ΔV, to control the positive wave of the electric m voltage, and
The trigger voltage (CI, C
The phase angle of the transducer voltage of x increases (the conduction angle decreases), and the same L! Compared to the case of l#I constant, phase control from the low output side becomes more effective, and the problem of hysteresis phenomenon is essentially solved.

[Example] Hereinafter, the present invention will be explained in detail with reference to FIGS. 3 and 4. In Fig. 3, Vl (1, cl and V R2, C) are slow-acting w1 variable 1L capacitors, respectively, and are phase circuits for control.L)1, Dl are diodes, respectively, and are connected to the CI, C Produces residual voltage in the opposite direction. A trigger voltage is taken out from the intermediate leap point of Dl and 02 and is connected to the gate of a triac that is a semiconductor switching element of Sl through a diac that is a trigger element of S2. The positive wave trigger current that controls the positive wave of the power supply voltage is in the direction of C1 → DI-82, and the negative wave trigger current that controls the negative wave is C2L-8.
They flow in the direction of 2-D. Therefore, the hysteresis phenomenon does not appear at all, and since the residual voltage of the member appears in CI and the residual voltage of stop appears in C1, the control phase angle becomes large.

Phase control from low output to high output can be performed extremely smoothly. In addition, the old one is for security purposes, and R, C
is for preventing malfunction.

FIG. 4 has a phase V path similar to that in FIG. 3, and uses a pulse transformer to control the phase of AC power by connecting DC thyristors in antiparallel. There is no hysteresis phenomenon, and phase control can be performed smoothly from low output to high output. R1, Rλ, and R3 are security resistors. Although the present invention uses a diac as the trigger element, the present invention is not limited thereby.

[Effects of the Invention] According to the method of the present invention, the hysteresis phenomenon is essentially eliminated, and even if a trigger element with a high specific starting voltage (Vea) is used, control from low output is extremely smooth. It was hit, and the effect was great.

[Brief explanation of drawings]

Figure 1 is a 1!11 diagram for explaining the conventional trick. FIG. 2 provides a detailed explanation of the present invention. 3 and 4 are diagrams 1 to 11 showing embodiments of the present invention. E is intersection ff1tj1. L is a power device, SL is a switching element on both sides, S2 is a trigger element, 1' is a pulse transformer, υ+, Dz, Dwo, D4 is a diode, X1
1, 1' 2 is the SC (thyristor).

Claims (1)

[Claims] (1) It has two phase circuits each consisting of a semiconductor switching element that switches voltage from an AC power supply and supplies it to power equipment, an interlocking variable resistor, and a capacitor arranged in series. AC power phase control characterized by connecting two diodes in series in the same direction between the connection points of and connecting a trigger element between the intermediate connection point and the gate of the semiconductor switching element. circuit.