JPS5927080B2 - High frequency lighting fluorescent lamp dimmer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides preset dimming by using a constant power circuit for a high frequency variable power supply voltage input.

This invention relates to a high-frequency lighting fluorescent light control device. in general,
Electronic ballasts for residential use require a combination of stringent performance requirements such as RFI suppression and the use of preheat-activated fluorescent lamps, as well as a variety of functions such as rapid starting and dimmability. Also high. When talking about frequency lighting, for example, in the case of a large electric light of several hundred watts, the performance and functions that must be met are simple in a sense, but it can be understood that it is rather complicated for residential use. The present invention provides a high-frequency fluorescent lamp dimmer for residential use, which can satisfy both the above-mentioned severe performance and diverse functions. This will be explained in detail.

In Figure 1, E is a high-frequency variable voltage power supply, L is a fluorescent lamp, Z1 is a first impedance element connected to the terminal of the fluorescent lamp L on the opposite side from the power supply E, and Z2 is the power supply side of the power supply E and the fluorescent lamp L. A second impedance element Z3 connected in series with the terminal is a third impedance element connected in parallel to the power supply side terminal of the fluorescent lamp L, and this circuit applies a constant power to the first impedance element Z4 at startup. It is a constant power circuit that supplies .

In this circuit, since the lamp voltage El of the fluorescent lamp L is almost constant during lighting, the cathode heating current Ir necessary for dimming is given to E1-1 as =-constant Z4-.

Since the lamp current Id is proportional to the power supply voltage E, dimming is possible by varying and setting the high frequency power supply voltage.

At startup, a constant power circuit is formed by the second impedance element Z2 and the first and third impedance elements Z1 and Z3, and by giving almost constant power to the first impedance element Z1, the cathode preheating current Ipre and the startup voltage are adjusted. Es
Preset dimming is possible by keeping both t substantially constant.

Note that the constant power circuit includes the second isohedance element Z2 and the first
It can also be formed with an impedance element Z1.

FIG. 2 shows a series circuit of a first coil Li and a first capacitor Cl as the first impedance element Z1 in the circuit of FIG. The second capacitor C2 is used as the coil L2 and the third impedance element Z3, and FIG. 3 shows an equivalent circuit of the circuit in FIG. The case is shown in which the first impedance Z1 and the second impedance Z2 are connected to the opposite side of the power supply and are formed by combining the third impedance Z3 and the first impedance Z, and FIG. 5 is the equivalent of FIG. 4. It shows the circuit,
R1 is the equivalent lamp resistance that gives the effective values of the lamp current and lamp voltage, Rf is the filament resistance, and the inductances of the coils A, b, and c are the first and second coils Ll,
Letting the mutual inductance of L2 be M, it is L, +M, L2+M, -M for additive polarity, and L1-M, L2-M, +M for depolarization, respectively.

Next, various effects of this circuit will be explained in order.

1) Effective suppression of radio wave interference Due to the nonlinearity of the voltage-current characteristics of the lamp L during high-frequency lighting as shown in Figure 6, the harmonics drawn from the power supply E and the harmonics flowing in due to distortion of the power supply are , for the equivalent resistance R1 of the lamp L, the second coil L2 and the second
It is low-pass filtered by capacitor C2.

In this case, the harmonics filtered by the filter are ? Furthermore, it is attenuated by about 40 dB. In this way, it can be said that it is a desirable property that the lighting circuit itself constitutes a strong filter. In addition, as shown in FIG. 7, the second capacitor C2 in the side path is used to prevent anode vibration and cathode vibration that generate so-called fluorescent lamp noise.
works effectively and suppresses fluorescent lamp noise. 2) Rapid starch ink for preheat-starting fluorescent lamps Since preheat-starting fluorescent lamps are intended to be operated through a higher impedance than the power supply, rapid starch ink using cathode heating windings has good compatibility. I can't do specials.

In so-called rapid starch ink circuits for commercial waves, it is common to make the magnetic circuit as small as possible by using a small cathode heating current and a small starting voltage, but the trade-off for this is the use of a dedicated tube or a dedicated Use of starting aids. In order to obtain good compatibility with rapid starch ink using a preheat-starting fluorescent lamp, it is best to apply a sufficient cathode heating current under current source drive and a sufficient starting voltage. Good morning. In the case of high frequency lighting, the degree of freedom in the circuit is high and it is easy to adopt such a method, but in the circuit of this invention, the equivalent lamp resistance R=1 and the mutual reactance XM of the first coil L1 and the second coil L2 is 2. When the reactance XC2 of the capacitor C2 is much smaller than that, there is a relationship between the starting voltage Est, the lamp voltage El, the preheating current 1pre, and the cathode residual current 1r during lighting, and there is a degree of freedom in the power supply voltage E. Est/E2 or Ipre/Ir can take, for example, a value of 3 or 6, thus providing, so to speak, a sufficient preheating current 1pre as well as starting voltage Est. The starting voltage source is an order of magnitude stronger and the starting is reliable, there is no problem with the starter restarting, and it seems that it is probably compatible with a rapid start tube of the same rating. This circuit can be said to be in the best condition in terms of ensuring compatibility, but the trade-off for increasing compatibility is an increase in inverter capacity. One way is to minimize the continuous capacity by using suitable protectors with short-time ratings.

3) Possibility of dimming In order to perform dimming during high-frequency lighting, it is out of the question to perform flow angle control in the same way as when lighting on commercial waves, in view of radio wave interference.

In addition, variable impedance, and therefore variable frequency, can cause waveform distortion and deterioration of inverter efficiency due to inverter operation not being able to maintain its optimum point.
Furthermore, changing the operating frequency by a factor of 2 to 3 in order to reduce the total amount of light to 1/2 or 1/3 makes it difficult to achieve a balance between ultra-audio frequency operation and suppression of radio wave interference. It is out of the question to mechanically change the inductance, which is another type of variable impedance, and a simple experiment showed that variable inductance due to the weight of the bias DC is also out of the question in terms of radio wave interference due to nonlinear operation during lighting. . The most suitable method for dimming without causing waveform interference (radio wave interference) during high-frequency lighting is to use a fixed frequency and variable input voltage, since the high-frequency power supply voltage E and lamp current 1d are in a proportional relationship. Naturally, it is a hot cathode fluorescent lamp! Securing the cathode heating current necessary for dimming (usually a constant current is ensured by a heater transformer), preset dimming that is preferable in practice, and self-start without cold start even when dimming. In this circuit, the following is possible. In other words, providing an almost constant residual current Ir during lighting is achieved by the fact that, as a characteristic of the discharge lamp, the lamp voltage does not change much even if the lamp current is changed significantly and remains fairly constant. but,
As described above, since there is a high degree of freedom in selecting the preheating current 1pre, the residual current r, and the starting voltage Est, it should be possible to set them to predetermined values.

Note that it is rather preferable that the lamp voltage increases slightly when the lamp current is reduced because the residual current 1r increases somewhat. In this circuit, the preheating current 1pre and the starting voltage Est are roughly in a proportional relationship, so with regard to cathode wear during starting, the preheating current 1pre and the starting voltage Est can be considered to be in a complementary relationship, and the power supply voltage E Good starting characteristics should be maintained if the change in preheating current 1pre with respect to 2 changes in , and therefore the change in starting voltage Est, is kept approximately constant. Preheating current 1pre
Keeping the starting voltage Est almost constant means that this circuit is a kind of multiple resonance circuit, and in places where the power supply voltage 3 voltage E is high, the first
The preheating current 1pre and the starting voltage Est are controlled by a so-called constant power circuit consisting of the saturation of the inductor in a phase advance circuit consisting of the capacitor C1 and the first coil L1 connected in series with the capacitor C1.
This suppresses changes in the power supply voltage E, and compensates for low power supply voltage E by boosting due to resonance between the second coil L2 and the second capacitor C2. In the case of additive polarity, the magnetomotive force at startup is three times as large as the magnetomotive force during lighting, so that saturable operation at startup and non-saturated operation during lighting can be used. Figure 8 shows the magnetic circuit. A ferrite core is used, the mutual inductance is polarized, a standard high frequency power supply and a pseudo load are used, the starting voltage Est, the preheating voltage R, .

This shows the power supply voltage characteristics of La.7P Raiju A. As shown in FIG. 8, in the case of the circuit of the present invention in which the bypass current of the second capacitor C2 in the bypass flows to the electrodes of the lamp, the cathode residual current 1r increases, and the cathode residual current 1r is increased. Not only is it advantageous when choosing
As will be described later, since the cathode preheating current Ipre increases significantly, the cathode is instantaneously preheated, making practical instantaneous start-up possible without cold start.

This not only greatly shortens the time required for starting, but also greatly reduces cathode wear during starting, which allows the starting voltage Est to be selected higher, thereby ensuring more reliable lamp starting, and reducing the cathode wear during starting. This will further improve compatibility. In the case of the present invention, the preheating current 1pre increases significantly because in the equivalent circuit of FIG. 5, in the case of additive polarity, the reactance Xc of C is . It is equalized by the reactance of the equivalent capacitor Ceq, and at startup, L,,L2 decreases due to saturation, so Ceq increases, and the lamp resistance? and second capacitor C2
This is because the current distribution to the second capacitor C2 increases as the equivalent capacitor Ceq connected in series to the parallel circuit increases.

This tendency becomes more pronounced as the capacitance of the second capacitor C2 is selected to be larger than that of the first capacitor C1. 1) Long life When using this circuit and increasing the lamp current 1d, a double spot is formed, which is 90% of the lamp current.
Based on the cathode residual (heating) current with advanced phase,
Although it is incomplete due to single pin power supply, it is judged that it forms a high output lighting circuit or a long life circuit.

However, in this type of application, it is not appropriate to use it for high-output lighting where the luminous efficiency is reduced because of the incomplete balance caused by single-pin power supply. Rather, it is more useful to consider that a slight increase in lamp current does not cause problems with life, so the number of parts is large overall, and that this can be used as a basis for controlling a system in which lamp current values tend to vary. Will. 5) Simplicity There is no need to use a leakage magnetic path in the magnetic circuit, a structure with a normal coupling coefficient of approximately 1 is sufficient, and the circuit elements are 1 core and 2
It has a coil and two capacitors, and considering its function, it can be said to have a simple configuration.

Also, since the resonance with the second capacitor C2 in the side path is at a low saturation point, it is convenient that accuracy can be easily maintained. As described above, according to the high frequency lighting fluorescent lamp dimmer of the present invention, the first
By forming a constant power circuit for the impedance element and increasing the equivalent capacitor Ceq, a large, almost constant cathode preheating current and starting voltage are provided, and during lighting, a large, almost constant cathode heating current is provided depending on the lamp voltage. This allows for preset dimming, as well as various benefits such as effective suppression of radio interference, instant starch ink for preheat-activated fluorescent lamps, dimmability, long life, and simplicity. It is something that you have.

In Japanese Patent No. 1194674 (Japanese Patent Publication No. 58-26638), which is an additional related original invention, a fluorescent lamp L
The second capacitor C2 is connected to the power supply E side of the fluorescent lamp L so that the high frequency lighting dimmer will not become open load (no load state) with respect to the power supply E even if the filament is not inserted or the filament is disconnected. Therefore, the current flowing through the second capacitor C2 is equal to the preheating current 1p.
The trade-off is an increase in reactive current and a decrease in circuit power factor without contributing to re or cathode residual current Ir, but in the present invention, open load countermeasures are incorporated into power supply E to reduce open load. By inserting and connecting the second capacitor C2 to the non-power supply side of the fluorescent lamp L, the current flowing through the second capacitor C2 increases the reactive current and therefore decreases the circuit power factor. At startup, the current flowing to the second capacitor C2 tends to increase due to the saturation of the first coil L and the second coil L2, which is effective in keeping the preheating current 1pre high.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a high-frequency lighting fluorescent lamp dimmer device which is the basis of this invention, Figs. 2 and 4 are circuit diagrams of a more detailed embodiment of the circuit in Fig. 1, and Figs. Figure 5 is an equivalent circuit diagram of the circuits in Figures 2 and 4, Figure 6 is a voltage-current characteristic diagram during high-frequency lighting of a general fluorescent lamp, and Figure 7 is the circuit in Figures 2 and 4. The voltage-current characteristic diagram of a fluorescent lamp, Figure 8, uses a ferrite core in the magnetic circuit, and the mutual inductance is polarized.
The diagram shows various characteristics of the power supply voltage when using a standard high-frequency power supply and a dummy load. E: variable voltage power supply, L: lamp,
Zl, Z2, Z3...First, second and third impedance elements, L1L2゛0゜゜゜1 first and second coils, ClyC2゛゜゛''3゜first and second capacitors.

Claims (1)

[Claims] 1. A variable voltage high frequency power source, a first impedance element provided at both ends of a fluorescent lamp on the opposite side from the power source, and a second impedance element provided between the power source and the power source side of the fluorescent lamp, The first impedance element is a circuit in which a second capacitor is further connected in parallel to a series circuit of a first coil and a first capacitor, and the second impedance element is connected to a series circuit of a first coil and a first capacitor.
A high-frequency lighting fluorescent lamp dimmer device characterized in that the second coil is provided in a common magnetic path with the coil.