JPH09224380A - Inverter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restart the oscillation of an inverter securely even after the replacement of an electric light load and after turning ON/OFF of the load by a method wherein the voltage supply source of a starting circuit is obtained from the center connection point between two series-connected capacitors which are connected between both the terminals of an AC power supply and and between two resistors which are connected in parallel to the respective capacitors. SOLUTION: A timing at which a voltage whose phase is controlled by a dimmer 200 is applied between power supply lines and a timing at which the divided voltage is applied to a trigger device 111 are same. At that time, if a voltage applied to the trigger device 111 exceeds the breakover voltage of the trigger device 111, the trigger device 111 is quickly turned on and the charge stored in a capacitor 115 or 116 is made to flow into the base of a transistor 104 through a resistor 109 and an inverter starts oscillation. Therefore, when the inverter stops operation once and then restarts the operation, the trigger device is not kept in an ON-state and the operation can be restarted securely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a self-excited inverter device for lighting an incandescent light bulb such as a halogen light bulb, and is particularly suitable for use in combination with a current adjusting device for an electric light load as described above. The present invention relates to an inverter device.

[0002]

2. Description of the Related Art For example, an inverter device is generally used as a lighting device for lighting a halogen bulb, and in particular, a self-excited inverter device is widely used because of its simple circuit configuration. FIG. 3 shows an example of a self-excited inverter device used for lighting a halogen bulb.

The inverter device shown in FIG.
Full-wave rectifier 302 for full-wave rectifying the alternating current from 01
And transistors 303 and 304 connected in series to the full-wave rectifier 302, and capacitors 305 and 306 also connected in series to the full-wave rectifier 302. And
Between the connection point of the emitter of the transistor 303 and the collector of the transistor 304 and the connection point of the capacitors 305 and 306, the base transformer 307 and the step-down transformer 3 are connected.
A series circuit of 08 primary windings 307a and 308a is connected.

The base transformer 307 has two secondary windings 307b and 307c, the secondary winding 307b is connected between the base and emitter of the transistor 303, and the secondary winding 307c is the base of the transistor 304. -Connected between the emitters. Further, a series circuit of a resistor 309 and a capacitor 310 is connected to the full-wave rectifier 302, and a starting circuit is formed so as to be connected to the base of the transistor 304 via the trigger element 311 from the connection point of the resistor 309 and the capacitor 310. ing.

The inverter device according to the illustrated example is constructed as described above, and its operation will be described below. First, when the power is turned on, the capacitor 310 is charged with electric charge via the resistor 309, and the voltage is applied to the trigger element 31.
When the turn-on voltage of 1 is reached, the trigger element 311 is turned on.

Therefore, the charge charged in the capacitor 310 is supplied to the base of the transistor 304 via the trigger element 311, and the transistor 304 is turned on.
As a result, a current flows from the full-wave rectifier 302 to the capacitor 305 → the primary winding 307a of the base transformer 307 → the primary winding 308a of the step-down transformer 308 → the transistor 304 → the full-wave rectifier 302, and at this time, the base transformer 307 The transistor 304 maintains the ON state by the voltage generated in the secondary winding 307c, while the transistor 303 is completely turned off by applying the reverse voltage generated in the secondary winding 307b of the base transformer 307 to its base.

After that, when a certain period of time elapses, the base transformer 307 is completely saturated and the transistor 3
No current flows through the base of the transistor 04.
04 is turned off. And the base transformer 307
Since the respective voltages of the secondary windings 307b and 307c are inverted, a current is supplied to the base of the transistor 303, the transistor 303 is turned on, and the full-wave rectifier 302 causes the transistor 303 → the primary winding 3 of the step-down transformer 308.
08a → primary winding 307a of the base transformer 307 → current flows through the path of the capacitor 306.

As described above, the transistors 303 and 304
Turns on and off alternately, resulting in step-down transformer 3
A high-frequency voltage is generated in the primary winding 308a of the 08, and the voltage stepped down by the secondary winding 308b of the step-down transformer 308 is supplied to the load 312 such as a halogen bulb to light.
However, in such an inverter device, for example, when the halogen bulb 312 is not lit due to its life or the like and is replaced, or when an ON / OFF switch is connected in series with the halogen bulb 312, the load 312 is turned ON / O.
When FF or the like is performed, since the holding current of the trigger element 311 of the starting circuit varies, the trigger element 311 is caused by the current flowing through the resistor 309 to the trigger element 311.
11 may be kept in the ON state.

As a result, electric charge is not stored in the capacitor 306, a starting current does not flow in the base of the transistor 304, and the inverter device cannot oscillate again. In order to solve such a problem, an inverter device as disclosed in, for example, Japanese Patent Laid-Open No. 2-256194 has been proposed. The structure is shown in FIG.

This inverter device includes a time constant circuit having a resistor 409 and a capacitor 410, and a trigger element 41.
A starter circuit having 1 and a voltage supply source of the time constant circuit and the starter circuit are connected in series to both ends of an AC power supply.
The impedance elements 413 and 414 are supplied from the midpoint of connection. As a result, a DC current that draws a one-sided sine wave is charged in the capacitor 410 of the time constant circuit via the resistor 413 or 414, and when the ON voltage of the trigger element 411 of the starting circuit is reached, the trigger element 411 turns ON. It operates and the inverter starts. Since the trigger element is turned on by using the one-sided sine wave direct current as the voltage supply source in this way, the supply current (supply voltage) to the trigger element always passes through the zero potential.
At that time, the trigger element is turned off regardless of the variation in the holding current of the trigger element. Therefore, for example, when the load such as a halogen bulb is replaced or the load is turned ON / OFF.
Even when it is turned off, stable re-oscillation can always be performed.

[0011]

By the way, in the inverter device shown in FIG. 4, when dimming an electric lamp load 412 such as a halogen bulb, an AC power supply 401 is generally used.
And the rectifier circuit 402 between the dimming device 2 as shown in FIG.
It is usual to connect 00. The device shown in FIG. 2 comprises a semiconductor switching element 201 such as a triac and a circuit for giving a gate signal to the semiconductor switching element 201. The semiconductor switching element 201 controls the phase of the AC voltage supplied from the AC power source to regulate the current to the lamp load. It is something to do.

However, when the dimmer as shown in FIG. 2 is used in combination with the inverter device as shown in FIG. 4, due to the charging current to the capacitor 410 used in the time constant circuit of the starting circuit of the inverter device. Since the start of the inverter device is started every half cycle of the power supply with a delay of this time constant, the gate signal is input to the triac 201 used in the dimmer, and the triac 201 is turned on. Even then, the inverter device does not start immediately, and as a result, the triac 201 becomes unable to secure the holding current and immediately turns off. Therefore, there is a problem that the inverter is not normally started and the dimming of the electric lamp load cannot be performed.

The present invention has been made in view of the above-mentioned problems of the prior art, and its object is to replace the electric lamp load or to turn on / off the lamp.
It is an object of the present invention to provide a self-excited inverter device that can surely re-oscillate even when it is turned off and that can perform dimming using a dimming device by adjusting a load current.

[0014]

In order to achieve the above object, the invention of claim 1 has a rectifying circuit for rectifying an alternating current supplied from an alternating current power source, and two rectifying circuits are provided at an output end of the rectifying circuit. A series circuit of transistors and a series circuit of two capacitors are connected in parallel, and a load circuit is provided between the connection midpoints of the series circuits. By turning on and off the transistors, the output current of the rectifier circuit is high frequency. In a self-excited inverter device for converting into a current, a starting circuit of the transistor is composed of a series circuit of a resistor and a trigger element, and a voltage supply source of the starting circuit is two capacitors connected in series at both ends of the AC power supply. , Obtained from the midpoint of connection of resistors connected in parallel to each of the capacitors. According to a second aspect of the present invention, a load current adjusting device is connected between the AC power supply and the rectifier circuit to adjust the current to the load by phase-controlling the AC voltage supplied from the AC power supply by the semiconductor switching element. Is characterized by.

[0015]

FIG. 1 shows a self-excited inverter device embodying the present invention. The difference between this device and the inverter device shown in FIGS. 3 and 4 is that capacitors 115 and 116 for starting energy charging are connected between AC power supply lines, and the midpoint between them and the midpoint between impedance elements 113 and 114. Resistor 109 and trigger element 111 from the connection point
The configuration is such that it is connected to the base line of the transistor 104 via.

Reference numeral 200 in the figure is a load current adjusting device for adjusting the current to the load 112. When a light load such as a halogen bulb is connected as the load 112,
Functions as a dimmer. This load current adjusting device 200
As shown in FIG. 2, a bidirectional switching element (triac) 201, a trigger element 202 for activating it, resistors 203 and 204 of a time constant circuit that determines the activation timing, a variable resistor 205, and It is composed of a capacitor 206 and the like.

When the dimmer 200 as shown in FIG. 2 is used in combination with the inverter device shown in FIG. 1, an AC voltage whose phase is controlled by the dimmer 200 is applied between the power lines, and the trigger element 111 is applied. The voltage is applied to resistors 113 and 1
The voltage divided by 14 will be applied. As a result, the voltage applied to the trigger element 111 is a one-sided sinusoidal voltage obtained by dividing the voltage applied between the power supply lines by the resistors 113 and 114, and the voltage from the power supply to the resistors 413, 414 and the like as in the inverter device shown in FIG. It does not become the voltage across the capacitor 410 in the time constant circuit for charging the capacitor 410 via 409. Therefore, after the power supply voltage is applied as in the device of FIG.
The phenomenon that the voltage is applied to the trigger element 411 with a delay of the charging time of 10 disappears.

That is, in the inverter device of FIG. 1, the timing at which the voltage phase-controlled by the light control device 200 is applied between the power supply lines (the timing at which the triac 201 of the light control device 200 is turned on) and the trigger element 111 correspondingly. The timing of applying the compressed voltage is the same. At that time, if the voltage applied to the trigger element 111 is equal to or higher than the breakover voltage of the trigger element 111, the trigger element 111 is immediately turned on and the capacitor 115
Alternatively, the charge charged in 116 flows into the base of the transistor 104 through the resistor 109, and the inverter device starts oscillating. As a result, the start-up delay of the inverter device relative to the start-up circuit as in the inverter device shown in FIG. 4 makes the triac of the dimming device unstable, and the input voltage to the inverter device becomes unstable accordingly. Is not started normally,
It is possible to avoid the problem that the dimming operation cannot be performed.

[0019]

As described above, in the inverter device according to the present invention, in the starting circuit in the inverter device, there is no starting delay due to the capacitor charging time of the time constant circuit, and the voltage source of the starting circuit is the power source. It is a one-sided sine wave obtained from the midpoint of connection of two resistors connected in series between lines. Therefore, the voltage applied to the trigger element used in the starting circuit in the inverter device always passes the zero potential in each half cycle of the AC voltage, so that even if the holding current of the trigger element varies. The trigger element is surely turned off every half cycle. Therefore, when the inverter device is re-oscillated after being temporarily stopped due to a no-load state or the like, the trigger element does not keep the ON state, and the trigger device can be reliably restarted.

Further, the unstable operation of the light control device due to the delay in starting the inverter device with respect to the starter circuit is eliminated, and stable light control operation can be performed. As described above, the inverter device having the circuit configuration as shown in FIG.
Even if a dimming device that controls the phase of the AC voltage with a semiconductor switching element to adjust the current to the electric lamp load, the electric lamp load such as a halogen bulb can be appropriately dimmed, and the electric lamp load can be replaced. Alternatively, even if the operation of the inverter device is once stopped by turning on / off a switch inserted in series with the electric light load, it is possible to surely re-oscillate if necessary.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an inverter device according to the present invention.

FIG. 2 is a circuit diagram of a load current adjusting device used in combination with an inverter device.

FIG. 3 is a circuit diagram of a conventional inverter device.

FIG. 4 is a circuit diagram of a conventional inverter device.

[Explanation of symbols]

101,301,401 AC power supply 102,302,402 Full-wave rectifier 103,104,303,304,403,404
Switching transistors 105, 106, 305, 306, 405, 406
Capacitor 107,307,407 Base transformer 108,308,408 Output down transformer 309,409 Time constant circuit resistance 310,410 Time constant circuit capacitor 111,311,411 Start circuit trigger element 112,312,412 Light load 413,414 minutes Resistors for voltage 115,116 Start-up circuit capacitor 200 Load current adjusting device (dimmer) 201 Bidirectional switching element (triac) 202 Dimmer trigger element 203,204 Dimmer resistor 205 Dimmer variable resistor 206 Dimmer Capacitor

Claims (2)

[Claims] 1. A rectifier circuit for rectifying an alternating current supplied from an alternating current power source, wherein a series circuit of two transistors and a series circuit of two capacitors are connected in parallel to an output terminal of the rectification circuit. In a self-excited inverter device in which a load circuit is provided between the connection midpoints of the series circuits and the output current of the rectifier circuit is converted into a high-frequency current by turning the transistor on and off, a starting circuit for the transistor is triggered by a resistor and a trigger. A series circuit of elements is used, and the voltage supply source of the starting circuit is obtained from the connection midpoint of two capacitors connected in series at both ends of the AC power source and resistors connected in parallel to each of the capacitors. Characteristic inverter device. 2. A load current adjusting device is connected between the AC power supply and the rectifying circuit to control the phase of the AC voltage supplied from the AC power supply by the semiconductor switching element to adjust the current to the load. The inverter device according to claim 1.