JPS59157724A - Phase control circuit of ac power using tripod transformer - Google Patents

Abstract

PURPOSE:To eliminate a danger of electric shock and to control the phase in a wide range by controlling the firing angle of a switching element with the output signal of a tertiary coil of a tripod transformer coupled electromagnetically with a firing angle control part. CONSTITUTION:When a switch 17 is opened, transistors TRs Q2 and Q1 are not operated, and a voltage is not generated in a tertiary coil 8 at all. But when the switch 17 is closed, a capacitor 20 is charged, and TRs Q2 and Q1 are made conductive when the capacitor 20 reaches a prescribed voltage value. In this case, since TRs Q1 and Q2 are made conductive while showing a negative resistance, the electric charge of the capacitor 20 is discharged, and a pulse is generated synchronously with a power source frequency, and a TR21 is made cnductive to short-circuit a secondary coil 7. Then, a voltage is induced in the tertiary coil (360 deg. or less behind the power source frequency), and a switching element 14 is fired in accordance with short-circuit of the coil 7, and a voltage is applied to a load. The value of a variable resistance 19 is changed to control the phase in the range of 0-180 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safe AC power phase control circuit that uses a tripod transformer to completely isolate a phase control operation circuit from a power source without the risk of electric shock.

Conventionally, all AC power phase control circuits using triacs and the like have been directly connected to an AC power source, so there is a risk of electric shock when performing phase control operations. To solve this problem, when performing remote control from the low voltage operation circuit side, when using a photocoupler non-contact relay as shown in Figure 1, a power supply (DC or AC) is required for operation input, and on/off control is required. Even if it was possible to do so, phase control was not possible, so a separate control circuit was required for phase control. Furthermore, even if a transformer is used as shown in Figure 2, if remote control is performed using a pulse generator circuit and triac gate, it is necessary to separately use a step-down transformer, pulse transformer, photocoupler, reed relay, etc. that is insulated from the power supply. Also, the wiring of the power supply and operation circuit becomes complicated.
There was some zoni that was expensive.

In view of the drawbacks of the conventional circuit, the present invention provides a low-voltage firing angle control section that is completely insulated from the AC power source on the primary side of the tripod transformer, and also provides electromagnetic coupling with the firing angle control section. The present invention aims to provide a circuit that controls the phase of AC power by controlling the firing angle of a non-contact switching element using the output signal of a tertiary coil.

The configuration of the present invention will be explained based on drawings of embodiments thereof. First, in the tripod transformer used in the present invention, as shown in FIG. 9, the tripod core has an outer leg and a center leg 3, and a gap j is provided in the outer leg.

A primary coil 6 is wound around the outer leg λ, and a primary coil 6 is wound around the outer leg λ.
The secondary coil 7 is on the other outer leg, and the tertiary coil is on the other outer leg. are wound so that a low voltage is induced in each. Does the tripod transformer l in Figure 5 have two cores? , 10 are isolated and coupled with a non-magnetic material l/ to form a tripod core, with a seventh coil 6 on the outer legs and a secondary coil 7 on the wide central leg 3.
The structure of the tripod core is different from that shown in FIG. 9 because the tertiary coils l are wound around the other outer legs.

Next, FIG. 3 shows an example circuit of the present invention in which the tripod transformer described above is used, both ends of the primary coil 60 are connected to the power supply /2, and one end of the tertiary coil l is connected in parallel to the power supply lλ. A non-contact switching element in series with the load /3 / a diode connected in anti-parallel to the gate of /! , connect via /j,
The other end is the non-contact switch 1. In addition to connecting to the cathode of the switching element/4t, the secondary coil 7 of the center leg 3 is connected to the full-wave rectifier 16, and a resistor/11 switch/7, a variable resistor l, and a capacitor are connected between both ends of the DC side. Series circuit and NPN transistor21. (collector connected to + side, emitter connected to one side) and two resistors connected in series, 2
2.23 and connect the connection point of the resistor 22.23 to NP
An N-type, PNPNPN transistor Qt is connected to the gate G of the coupling circuit 2da, and a resistor 2j'' is connected to the base of the NPN-type transistor 2/ through a voltage dividing circuit of 2o, and further the NPN type, PNP transistor Q+
The anode A of the Q-coupled circuit cog is connected to the connection point between the variable resistor /9 and the capacitor 20.

First, the operation of the tripod transformer will be explained, and then the operation and operation of the present invention will be explained. In Figure 2, the primary coil B is connected to the power supply/
2 and energized, if the secondary coil 7 is open, /electromagnetic flux ψ[ is as shown by the solid line, most of the magnetic flux ψ, ' is energized by the central leg 3. A voltage (e.g. /, 2V) induces a gap! Since only a small amount of leakage magnetic flux ψ" passes through the outer leg, only a very small voltage is generated in the tertiary coil ♂. However, when the secondary coil 2 is short-circuited with the switch 77', a short-circuit current flows. A λ electromagnetic flux ψ in the opposite direction to the magnetic flux ψ1' is generated and is divided into the magnetic flux ψl on the outer leg side and the magnetic flux ψ?' on the outer leg λ side as shown by the dotted line, and the magnetic flux ψ// increased by the short circuit and the above Since the composite magnetic flux with the magnetic flux ψl' passes through the outer leg Da where there is a gap!, the tertiary coil ♂ has a voltage that is slightly behind the power supply voltage by JtO degrees, that is, it is considered to be slightly ahead of the power supply voltage (bold line in Figure 7). The induced voltage (thin line in Figure 2) is induced.
The composite type tripod transformer / in the figure is attached to the primary coil 6 / 7
9. A low voltage is induced in the secondary coil 7 through the inner iron core as shown by the solid line.

However, since almost no leakage magnetic flux passes through the outer legs of the inner iron core IO, no voltage is generated in the tertiary coil l. However, when the secondary coil 7 is short-circuited with the switch 77', a short-circuit current flows, and 2 electromagnetic fluxes ψt are generated in the opposite direction to 1 electromagnetic flux ψ1.
occurs, and a magnetic circuit is created by interlinking with the tertiary coil l as shown by the dotted line in the core type iron core IO with low magnetic resistance, so the voltage is slightly less than 360 degrees behind the power supply voltage, that is, it is slightly ahead of the power supply voltage. A low voltage is considered to be induced. In both cases of FIG. 9 and FIG. 3, in response to a short circuit in the secondary coil 7, a voltage is induced in the tertiary coil l that is delayed by a little less than 3 tO degrees, that is, a voltage that is approximately in phase with the power supply but slightly ahead of it. The effect of the present invention utilizing this effect will be explained with reference to FIG. 3 of the embodiment.

When the switch 12 is open, the anode A (PNP
fi) Since no voltage is applied to the emitter of transistor Q, transistors Q and Q do not operate, and therefore are NPN.
Since no voltage is applied to the base of type transistor 2/, NPN type transistor 2t is off and does not short-circuit secondary coil 7 via full-wave rectifier /6, so no voltage is generated in tertiary coil l. do not. Therefore, since no signal is applied to the gate of the non-contact switching element /Z, it does not fire. However, when the switch 17 is closed, the capacitor 20 is charged through the resistor l/ and the variable resistor 19, and the voltage is applied to the NP divided by the resistor J, 21.2J.
When the voltage of the N-type and PNP-type transistor Q1 exceeds the voltage of the gate G of the coupling circuit 2, a gate current 0 flows from the anode A to the gate G, and the PNPNP-type transistor Q becomes conductive. The collector current IC of the PNP type transistor is NP
The base current of the N-type transistor IQ+ turns on the transistor Q, and the collector current flows, causing the gate current of the P'NP-type transistor Q. strengthen. Since the current gain of both transistors QIQJ increases as the current increases, they quickly reach a positive feedback state and exhibit negative resistance and become conductive, so the charge in the capacitor 20 is discharged and the change in variable resistance causes /- during the secondary cycle. Charging and discharging is repeated over 10 times, and a pulse signal (for example, Figure 2) is generated in synchronization with the power supply frequency, and the cathode current flows through the resistor 2! , 2t, causing a voltage drop, and a voltage of 2J is applied to the base of the NPN transistor 21, which turns on and short-circuits the secondary coil 7 via the full-wave rectifier 16. Therefore, from the characteristics of the tripod transformer l mentioned above, a voltage corresponding to the short circuit of the secondary coil 7 (Fig. 7 E) is induced in the tertiary coil r, and the antiparallel diode /jS /! ' is applied to the gate of the non-contact switching element /(t. Therefore, the non-contact switching element /% is fired in response to the short circuit of the co-order coil 7, and a voltage with a waveform as shown in Fig. 7 is applied to the load. The charging time can be changed by the variable resistor/9, so NP
N type, PNP type transistor QI Ql coupling circuit, 24
Since the turn-on timing of t, that is, the phase angle, can be changed by approximately θ to //θ degrees, the voltage of the tertiary coil l (λ-th coil When short-circuited, the thin line in Figure 2 A) has a slight lead phase shift, so the non-contact switching element/
& allows zero-cross ignition and phase control of the load power in a range of approximately O to /lθ degrees.

Also, as shown in Figure 6 (NPN type, PNP type transistors Q, Q
The same effect can be achieved even if the a-coupling circuit 24t is replaced with a PUT 24t'.

Although the winding configuration of the tripod transformer l is limited, in Fig. 9, the positions of the 7th coil 6 and the secondary coil 7 are exchanged, and the gap! It is possible to perform combinations such as installing the tertiary coil ♂ on the central leg and winding the tertiary coil ♂, or converting the primary coil ≦ into a joint leg body or the tertiary coil ♂ into a joint leg body in Fig. 5. Considering the influence of the leakage magnetic flux of both types of tripod transformers on the tertiary coil, the method of limiting is the best method with the least amount υ, and it is also the best method in terms of ease of manufacture and cost.

Also, since the voltage of the tertiary coil when the secondary coil is open is small, λ anti-parallel diodes/! There is also the advantage that malfunction of the non-contact switching element/4t can be sufficiently prevented with a voltage drop of . The resistor 27 and capacitor 2♂ are a protection circuit for the element/g, and the capacitor 2 is for peak absorption.

As described above, the present invention uses a tripod transformer to completely isolate the power supply and the low voltage phase control operation circuit, so there is no risk of electric shock.

The non-contact switching element can be fired at zero cross by utilizing the phase shift characteristic of the tripod transformer, making it possible not only to turn on and off but also to control the phase of AC power over a wide range.

The secondary coil of the tripod transformer is used as a low-voltage operating circuit power supply, and a simplified phase control circuit is installed to induce an equivalent pulse signal in the tertiary coil by short-circuit opening of the secondary coil and phase-controlled short-circuit opening. Since the gate signal is applied as a gate signal, there is an advantage that a separate power supply is not required.

It has the feature that the switch and variable resistance part can be taken out from terminals a and b for remote control.

The control circuit has a low voltage and a small current, so the tripod transformer can be made compact, and the circuit of the present invention has a small number of parts and the wiring is simple, so it can be made at a low cost.The characteristic effects of the present invention are extremely remarkable.

[Brief explanation of drawings]

1 and 2 are conventional control circuits, FIG. 3 is a phase control circuit according to an embodiment of the present invention, and FIG. 9 is a configuration diagram of a tripod transformer having a gap in the monopod used in the present invention. Fifth
The figure is also a configuration diagram of a tripod transformer of inner iron type and iron core composite type.
Figure 1 shows a circuit in which the transistor coupling circuit is replaced with a PUT, Figure 7 shows the voltage waveforms of various parts of the circuit of the present invention, and Figure 1 shows the power supply voltage waveform (thick line) and the tertiary voltage waveform when the secondary coil is shorted ( thin line), the opening is the voltage waveform applied to the base of transistor 2/ (during phase control), the voltage waveform between the collector and emitter of transistor 2/ (during phase control), 12 is the secondary voltage waveform during phase control , E is the tertiary voltage waveform during phase control,
Figures 1 and 2 show the load voltage waveforms during phase control. ／・・・・・・・・・Tripod transformer!・・・・・・・・・
・Gap≦・・・・・・7th coil 7...
...Secondary coil?・・・・・・・・・Tertiary coil
//...Non-magnetic material 14t...Non-contact switching element/9......Variable resistance
20・・・・・・・・・Capacitor 2/・・・・・・
・・・NPN type transistor 2g・・・・・・NP
N type, PNP type transistor combination circuit Q,...
... (NPNfi)) transistor Q2...
... (PNP type) transistor patent applicant Yasu Electric Co., Ltd.

Claims (3)

[Claims] (1) Wrap the primary coil around the outer leg of the tripod core and connect it to the power supply, and wind the tertiary coil around the other outer leg to connect the non-contact switching element in series with the load connected in parallel to the power supply. connected to the gate via an antiparallel diode, and the other end is connected to the cathode of the non-contact switching element,
A secondary coil is wound around the center leg and connected to a full wave rectifier.
A series circuit of a resistor, a switch, a variable resistor, and a capacitor, an NPN transistor, and two series-connected resistors are connected between both ends of the DC side, and the connection point of the resistors is connected to the NPN transistor.
and the cathode is connected to the gate of the NPN type and PNIl type transistor combination circuit, and the cathode is connected to the pace of the NPN type transistor by resistor voltage division, and the anode of the NPN type and PNP type transistor combination circuit is connected to the connection point of the variable resistor and the capacitor. AC power phase control circuit using a tripod transformer connected to (2) Claim 1, characterized in that the tertiary coil is wound with a gap provided in one of the outer legs of the tripod core.
An alternating current power phase control circuit using the tripod transformer described in . (3) A tripod transformer according to claim 1, characterized in that a secondary coil is wound around the central leg of a tripod core that is isolated and coupled with a non-magnetic material between the legs of λ inner iron cores. Phase control circuit for AC power used.