JPS5834595A - Device for firing discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A discharge lamp lighting device manufactured by the present invention, comprising an inverter circuit connected to the output terminal of a full-wave rectifier circuit connected to a low-frequency AC power supply, and a discharge lamp connected to the output terminal of the inverter circuit. Regarding.

A conventional discharge lamp device of this type is configured to connect a diode, bridge, or other full-wave rectifier circuit 3 input terminal to a commercial AC power source 1 to obtain a DC voltage, as shown in Fig. 1. For example, the DC power source is input to an inverter 8 which is a shoulder wave number converter to light the discharge lamp 4 at high frequency. However, in order to obtain a smoothed DC voltage at a constant level, a smoothing capacitor 6 is conventionally connected between the output terminals of the rectifier circuit 2, so a rest period occurs in the input current, resulting in an extremely poor input power factor. The problem arose. That is, the capacitor 6 is charged by the aftereffect rectified voltage (marked in Fig. 2), which is the output of the rectifier circuit 2, from the midway time 11 when the voltage rises until the peak time 1°, but the full-wave rectified voltage ( Since the capacitor voltage is higher from the peak time to the time shown in FIG. .Therefore, from time t1 to time [
1, the sum of the charging current from the AC power supply 1 to the capacitor 6 and the supply current to the inverter 8 becomes the input current.
As shown in c), since the waveform has a high peak value with a pause period, the input power factor becomes extremely poor.

As a method for improving this drawback, a circuit configuration shown in FIG. 8 has been proposed. That is, an anti-parallel circuit of a rectifier switch element S such as an 8-terminal control rectifier element, a diode D, and a series circuit with a capacitor CI is maintained between the output terminals of the rectifier circuit 2 via an inductance element. Further, the gate of the rectifying switch element S is connected to a gate control circuit 6 that applies a gate pulse at an arbitrary phase.

Now, connect the low frequency AC power supply, and time t1 shown in FIG.
As the power supply voltage increases beyond
The battery is charged as shown in . On the other hand, voltage is also applied to the input terminals of the capacitor t01 and the inverter Ja, and when the instantaneous value of the power supply voltage reaches its peak, the voltage applied to the inverter Jll and the capacitor C1 also reaches its peak. Thereafter, as the power supply voltage drops, the voltage across capacitor C and the input voltage of inverter 18 drop, but the voltage across capacitor CI is Vc.
1, since the rectifying switch element 8 is in the OFF state, the peak value is maintained as shown in FIG. 4(C). When the rectifier switch element S is turned on by the gate control circuit 6 at the time [Rose], the electric charge of the capacitor C1 that has been charged to Vcl peak is inverted via the rectifier switch element S! 8 and discharge. Therefore, a nearly constant voltage (see FIG. 4(b)) is applied to the input terminal of the inverter 80.

From time t3 to time 11, the discharge current of capacitor CI flows to the inverter, and the input current from the low frequency AC power source is as shown in Fig. 4). As with the conventional example, the waveform has a high peak value with a pause period, so it has the disadvantage of poor input power factor.

The present invention has been made to improve the above-mentioned drawbacks, and consists of connecting an inverter circuit to the output terminal of a full-wave rectifier connected to a low-frequency AC power source, and connecting a discharge lamp to the output end of the inverter circuit. To provide a discharge lamp lighting device which obtains a constant voltage level in the low frequency envelope of the voltage applied to the discharge lamp, and has a short pause period of input current and a good input power factor. be.

FIG. 6 is a principle diagram of the present invention, in which a full-wave rectifier circuit 2 connected to a low-frequency AC power source 1 is provided, an inverter circuit 8 is connected to the output terminal of the cough rectifier circuit 2, and the output terminal of the inverter circuit 8 is connected to the output terminal of the inverter circuit 8. A discharge lamp 4 is connected via a secondary winding having an inductance L, which will be described later. Further, a closed circuit including an inductance L and a switch S is formed in series with the rectified and smoothed DC power supply C formed by the low frequency AC power supply 1. The low voltage period (1 in Figure 6,
-1. period), the switch S is driven on and off at high frequency, and the voltage induced in the inductance L by the switch S is 2.
It is designed to be superimposed in series on the output voltage η of the inverter 1 circuit 8 via the next winding.

Fig. 6 line is an operation waveform diagram of the present invention, which is a low voltage period of every cycle y of the low frequency AC power source l (period t3-1 in Fig. 6).
When the switch S is turned on and off at high frequency, an induced voltage is generated in the inductance L. This induced voltage is superimposed in series on the output of the inverter circuit 3 by the secondary winding of the inductance L. In FIG. 6, the top is supplied to the invar 1 circuit 8 with a full wave rectified voltage.

Therefore, the output voltage v1 of the inverter 1 circuit 3 is (CI
Be like I. Then, when the switch S is driven on and off at high frequency only during the El-t1 period in Fig. 6, a voltage is induced in the inductance L, and a low voltage as shown in WJ (c) is induced in the secondary winding of the inductance L. The output voltage - of the partial compensation circuit 6 is obtained. Therefore, the voltage v3 applied to the discharge lamp 4 is equal to the output voltage v1 of the inverter circuit 8 and the output voltage of the low voltage section compensation circuit 6 -
The voltage Vsk and the low skin wave envelope become a substantially constant voltage. Moreover, a full-wave rectified voltage is applied to the inverter circuit 8, and a low-voltage compensation circuit 5' (see FIG. 8) is connected between the input voltage 1, the full-wave rectifier circuit 2, and the inverter circuit 8, as in the conventional case. Since there is no intervention, the input current becomes a current as shown in FIG. 6(E) without any pause period.

Next, during the high voltage period (period tl-t2 in FIG. 6) of each cycle of the low frequency AC power supply l, the switch S is turned off without being driven on or off. When switch S is turned off, the secondary winding with inductance L (DC resistance only)
In addition, since the resistance is very small, the output voltage η of the inverter circuit 8 is applied to the discharge lamp 4. (The switch S may be driven on and off during the E+-1t period, but considering the loss of the switch S, it is better to turn off the switch S□.) Figure 7 shows the present invention based on the above principle diagram. This is a circuit diagram showing one embodiment, and the symbols 1 to 6 in the figure are the symbols 1 to 5 in FIG.
1 (correspondingly, the inverter circuit 8 has a well-known inverter circuit configuration.C, the switch S shown in Fig. 45 is shared by the transistors 1 and 1 of the inverter 1 circuit 8, DC voltage e - inductance L, - the first closed circuit of the diode Hartungister, DC voltage e - inductance! - diode D, -
) A second closed circuit of the fungistor S3 is provided, and a secondary winding AIl nxt is provided in each inductance L1*"l.
, nu are provided, and the secondary winding "11@"H is connected in series between the inverter circuit 8 and the discharge lamp 40.

The operation of such a device is similar to that explained in the principle diagram above.
Since the switches Slm are also turned on and off alternately, the inductance L1. L! A high frequency voltage is generated at , and is superimposed in series with the output voltage of the inverter circuit 8 . Also,
Even during the low voltage period of the input voltage 1, the high frequency voltage generated by the DC voltage e operates in the same way as if it were substantially connected in series with the output voltage of the inverter 1 circuit 8, so that an almost constant high frequency voltage is applied to the discharge lamp 4. Furthermore, since there is no pause period for the input current, the human power factor is improved.

FIG. 8 is a circuit diagram showing various embodiments. Since the configuration and operation are almost the same as those of the previous embodiments, only the differences will be described. Connect a diode in parallel with the output terminal of
It is obtained by connecting sensor C1. Also, capacitor C+
(corresponding to DC voltage C in Figure 7) and inductance Ll
(Lzl - diode D, (D2) - transistor s
A switch S is provided between the series circuits of , (S2). The switch S receives the output signal of the control circuit 6 (turns on 9, the switch S turns on during the period when the input voltage is low,
Condenser 4) C, direct current q (pressure is Indus dance Ll
(L2) - Diode Dt (D2) - Transistor 5I (S2) is connected to a series circuit. The subsequent operations are the same as those in the previous embodiment, and will therefore be omitted.

G↓・, smoothed i obtained by rectifying and smoothing AC power supply voltage 1
The voltage (voltage of capacitor C1) t should be lower than the output voltage of the full-wave rectifier circuit 2 that full-wave rectifies the AC power supply l. The current and voltage of the power supply are connected to the inverter circuit, and the DC voltage and inductance obtained by rectifying the low-frequency AC voltage form a closed circuit of the switch, and the switch is turned on at high frequency during the low voltage period of the low-frequency AC voltage. , 7, and the induced voltage of the inductance is superimposed in series on the output voltage of the inverter circuit by the secondary winding of the inductance, and it is possible to supply an almost constant voltage to the discharge lamp. It was possible to provide a discharge lamp lighting device with improved input power factor during the rest period.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional example, Fig. 2 is an operating waveform diagram of each part of the same as above, Fig. 8 is a circuit diagram showing a different conventional example, Fig. 4 is an operating waveform diagram of each part of the same as above, and Fig. 6 is a diagram of this part. FIG. 6 is a circuit diagram explaining the invention in detail, FIG. 6 is an operation waveform diagram of each part of the same, and FIGS. 7 and 8 are circuit diagrams each showing an embodiment of the present invention. 111y! J 11!4 Figure 5z Figure 6! ! Figure 7/

Claims (1)

[Claims] 11) An aftereffect rectifier circuit that performs full-wave rectification of a low-frequency AC power source;
An inverter connected to the output end of this full-wave rectifier circuit,
A discharge lamp that is lit by this invar IO output, an inductance provided between the inverter and the discharge lamp, a smoothed voltage obtained by rectifying and smoothing the AC power supply voltage, a secondary winding of the inductance, and a switch element. A closed circuit is provided, which responds to voltage changes during each half cycle of the AC power supply, drives the switching element on and off at low voltage, and connects the voltage induced in the inductance in series with the output voltage of the inverter. A discharge lamp lighting device characterized by being superimposed on. +21 1i3. The discharge lamp lighting device according to claim 1, wherein the switch element is shared with the switch element of an inverter. (8) The discharge lamp lighting device according to claim 1, wherein the smoothed voltage is set to a voltage that is slightly lower than the peak value of the output voltage of the full-wave rectifier circuit.