JPS588119B2 - ladybug warmer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to reducing the size and weight of a phase advance type ballast used in a discharge lamp lighting circuit.

Conventionally, as a ballast for a discharge lamp such as a fluorescent lamp, an inductance or a series circuit system of an inductance and a capacitor has been mainly used.

In these systems, in the case of a low frequency such as a commercial 50 Hz or 60 Hz power source, the energy that must be stored in the ballast in one cycle becomes large, resulting in a large size.

The above inductance is heavy because it is made of iron and copper.

Therefore, conventional ballasts weigh several kilograms per 100W, and the lamp body in which the ballast is installed is required to be very strong.

In the case of high-power lamp fixtures, the weight of the ballast is heavy, which significantly increases the overall weight of the light fixture, and the installation location must be very strong, leading to accidents resulting in personal injury due to the light fixture falling from the ceiling.

Therefore, it is strongly desired that the stabilizer be made smaller and lighter.

Conventionally, as methods for reducing size and weight, methods of increasing the frequency using an inverter or chopper, reducing the inductance value for ballast, and resistive ballast have been considered.

However, the former has problems with reliability and noise due to its complicated circuit, and the latter has problems with efficiency, and currently both are used only for special purposes.

The present invention uses a saturated nonlinear capacitor as a phase advance capacitor in a phase advance ballast.
The aim is to reduce the inductance and make the entire ballast smaller and lighter.

The characteristics required of a discharge lamp ballast are (1) to have a current limiting effect, (2) to be able to obtain the restriking voltage of the discharge when the polarity of the current is reversed, and (3) to be able to restriking the discharge. (4) maintaining the lamp discharge from until the next restriking;
There are four main points to consider, including the ability to obtain stable discharge characteristics even when the power supply voltage fluctuates.

For example, in a saturated nonlinear capacitor having characteristics as shown in FIG. 3, when the slope Cs after saturation is 0, the charge flowing through it is Qs regardless of the applied voltage, and has a charge limiting characteristic.

This tendency also exists when Cs is not 0.

Therefore, if a saturated nonlinear capacitor is used as a part of the ballast, the above characteristics (1) and (4) are naturally satisfied, and the demands on other components are reduced.

Next, a more detailed explanation will be given using examples.

FIG. 1 shows a conventional phase advance type discharge lamp lighting circuit.

In the figure, V1 is an AC power supply, L is a discharge lamp, and B is a phase-advanced ballast circuit composed of an inductance channel and a capacitor C connected in series.

Waveforms of various parts during lighting are shown in FIGS. 4a and 4b.

Figure a shows the relationship among the power supply voltage V1, lamp voltage Vi, and ballast B voltage VB.

For purposes of explanation, VL is assumed to be an ideal short waveform.

Figure b shows the relationship between the voltage Vch of the inductance ch and the voltage Vc of the capacitor C.

The sum of Voh and Vc is VB. Note that here the current i
The waveform of L is also shown.

FIG. 2 shows an embodiment of the present invention, which is a circuit in which a saturated nonlinear capacitor FC is used in place of the capacitor C shown in FIG.

When a capacitor having ideal voltage/charge characteristics as shown in FIG. 3 is used as the saturated nonlinear capacitor FC, the voltage waveforms at various parts are as shown in FIGS. 4a and 4C.

Here, to facilitate comparison with the conventional circuit shown in Figure 1, the power supply voltage V1, lamp voltage VL, and ballast voltage V
Figure a, which shows the relationship between B and B, is the same.

The ballast characteristics of the circuit shown in Figure 1 are the same as those of the circuit shown in Figure 1.
FIG. 4C shows the voltage waveforms of the inductance L and the nonlinear capacitor FC provided in the ballast B shown in the figure.

As shown in Figure 3, the voltage/charge characteristics of the FC are such that when the amount of charge is +Qs to -Qs, the voltage is 0, and when the amount of charge is +Qs or more, -Qs
Below, it has a slope of capacitance Cs.

When using an FC with such characteristics, the FC during lighting operation
The voltage has a waveform that shows intermittent rises, as shown by VFC in FIG. 4C.

During the period of voltage 0, the change in the charge of FC is -Qs to +Qs
The period during which the voltage is rising is caused by the charging and discharging of the capacitor Cs.

Therefore, the lengths of these periods are determined by the current value and the magnitudes of Qs and Cs.

In order to make the ballast voltage VB obtained from FIG. 4a, the voltage applied to the inductance is Vch as shown in FIG. 4c.

This is the inductance voltage Vch of the conventional circuit shown in Figure 4b.
A voltage with apparently twice the frequency is applied compared to .

This result can be easily understood from the fact that, in general, when a circuit has a nonlinear component, a linear element also generates a harmonic component.

When the impedance is constant, the inductance is half proportional to the frequency, so it is clear that the inductance in FIG. 2 may be smaller than that in FIG. 1.

The waveform of the lamp current iL in FIG. 4b has a shape close to a sine wave, whereas in the case of FIG. 4c, the waveform has many harmonic components due to the nonlinearity of the FC.

A further requirement of the ballast, as previously mentioned, is that the lamp be energized for restriking when the polarity of the lamp current is reversed.

If the voltage for this re-ignition is not sufficient, the re-ignition phase may not be stable or a period of rest in the lamp current may occur.
This may cause the lamp to flicker.

In the circuit shown in Figure 1, the voltage for restriking is the voltage that was present in the inductance just before the current stopped flowing, and is equal to the voltage across capacitor C minus the power supply voltage and the lamp voltage just before the current stopped flowing. Become.

Therefore, in order to obtain the same restriking voltage as in FIG. 1 in the embodiment of FIG. 2, it is preferable to make the voltage of the nonlinear capacitor PC just before restriking equal to the voltage of the capacitor C of FIG. 1.

As is clear from FIG. 4, these capacitor voltages are higher than the power supply voltage and are caused by the transfer of current energy stored in the inductance into voltage energy in the capacitors, ie, resonance.

If the voltage of FC at the time of restriking is Vr and the amount of charge is Qr, then F
As shown in Fig. 3, the charging energy WFC of C is F
This is the energy required to charge C from a state of charge Qs and voltage 0 to a state of charge Qr and voltage Vr along the characteristic line of capacitance Cs, and the amount of charge to be charged in this case = Qr - Qs. Since charging voltage = Vr, WFC = 1/2 (Qr - Qs) Vr...
(1).

In addition, in FIG. 3, there is a relationship between the amount of charge Qr-Qs to be charged and the charging voltage Vr: Qr-Qs-CsVr...
・Since there is a relationship (2), substitute this into equation (1) and get WFC=1/2CsVr2 ・・・・・・・・・・・・
... It can also be expressed as (3).

On the other hand, in the case of the circuit shown in FIG. 1, the charging energy Wc of C is changed from the state of charge amount 0 and voltage 0 in FIG.
This is the energy required to charge C to a state where the amount of charge is Qr and the voltage is Vr along a characteristic line (not shown).

Therefore, as can be seen by comparing equations (1) and (4), it is clear that the charging energy of FC WFC
It can be seen that the charging energy Wc of C is smaller than the charging energy Wc of C.

Therefore, it can be seen from this fact that the inductance of the circuit of the embodiment shown in FIG. 2 may be smaller than that of the conventional circuit.

It can be seen that it can be smaller than that of the circuit.

In FIG. 3, the smaller Cs, the smaller the energy required to charge up to Vr, but after restriking,
C until the power supply voltage becomes higher than the discharge voltage of the lamp.
This C
The value of s cannot be lower than a certain value determined by the type of lamp and the value of inductance.

As mentioned above, as a phase advance type ballast capacitor,
Using a saturated nonlinear capacitor increases the frequency of the voltage across the inductance, another component of the ballast, and also makes it easier to obtain the lamp restriking voltage, thereby reducing the inductance.

Since most of the weight of the ballast is due to this inductance, it is possible to create a ballast that is smaller and lighter than before.

As the saturated nonlinear capacitor used in the present invention, it is currently possible to use a capacitor using a ferroelectric material such as lead zirconate titanate.

The characteristics of the voltage V and the charge Q are shown in Fig. 5 (a) and (b).

It is desirable that this V-Q characteristic has a small hysteresis area, a large rising slope in the unsaturated portion, and an appropriate slope Cs after saturation.

FIG. 6a shows an embodiment in which the present invention is applied to a circuit constructed using magnetic leakage transformers L and T.

L1 and L2 are two lamps that are lit in series.

C2 is a noise prevention capacitor, and C3 is a startup aid capacitor.

This configuration is the same as the conventional configuration except that a saturated nonlinear capacitor FC is used in place of the conventional linear capacitor.

Of course, the structure can be similarly configured for a single lamp.

Since the magnetic leakage transformers L and T can be approximated to a series circuit of a transformer and an inductance, the operation is the same as that of the embodiment shown in FIG.

Furthermore, by connecting a linear capacitor C1 in parallel to FC as shown in FIG. 6b, the capacitance Cs after saturation can be appropriately corrected.

Another advantage of the present invention is that the charge limiting characteristics of a nonlinear capacitor can be used to facilitate lamp starting by inducing a high voltage across the capacitor and applying it across the lamp.

For example, a starter can be configured by a circuit in which a bidirectional gate control switch FLS is connected to perform a gate trigger by passing an integrating circuit between the non-power supply side filament terminals P and P' of the lamp in a phase-advancing lighting circuit as shown in Fig. 7. .

A series circuit of a diode D1 and a resistor Rs, which are connected in parallel to the lamp between the power supply side terminals of the filament of the lamp, is intended to facilitate stopping the starter operation after lighting.

The starter circuit section including the above FLS is shown in the figure.
shall be.

The operation of this part is that when a voltage is applied to both ends in the off state, C4 is charged at a speed determined by the voltage and the integration circuit, the trigger element Diac is turned on, and the FLS is turned on.

In other words, the circuit is such that it can maintain an off state for a predetermined period of time even if a large voltage is applied.

The operation of the circuit shown in FIG. 7 is such that when S is turned on at a certain power supply phase, current flows through V1, ch, FC, the lamp filament, and the starter circuit S.

This heats the filament.

Since both ends of the lamp L are short-circuited by the starter S, this current has a high rising speed.

On the other hand, since FC has a charge limiting characteristic, the time for a half cycle in which current flows is considerably shorter than the time for a current cycle in the power supply voltage.

Moreover, as can be inferred from the case where Cs is set to 0 in Figure 3, the slope at the end of the current flow is quite large.
A nonlinear capacitor is charged to a high voltage.

When the current finishes flowing, a voltage obtained by superimposing the power supply voltage on this charging voltage is applied to the lamp L.

At this time, since the starter S is constructed so as not to turn on immediately, the above-mentioned high voltage is applied to the lamp for a certain period of time, and if the filament is sufficiently preheated, the lamp will be turned on.

If the nonlinear capacitor FC in Fig. 7 is a linear capacitor, it is not possible to sufficiently increase the voltage with such an operation only once, so the off-state maintenance time is increased and the phase through which the current flows is adjusted. The voltage is increased by repeating the operation many times.

Therefore, with the configuration shown in FIG. 7 using linear capacitors, it may not be possible to obtain a sufficiently high voltage.

However, with the method shown in FIG. 7 using a nonlinear capacitor, a sufficiently high voltage can be obtained with just one operation, so the off-state maintenance time may be short.

FIG. 8 shows an example of operation waveforms of the embodiment of FIG. 7.

V1 is the power supply voltage, i is the current, VFC is the FC voltage, VL
is the lamp applied voltage.

In this state, it is of course possible to obtain good starter characteristics even if a configuration is adopted in which the off-state is maintained for a longer time and the voltage is gradually increased, such as when a linear capacitor is used instead of an FC. .

Moreover, it goes without saying that preheating may be performed by a separate circuit.

FIG. 9 shows another configuration example of such a starter.

This is a circuit in which an SCR is connected through a full-wave rectifier Z, and its off-state maintenance time is controlled by a time constant circuit consisting of a capacitor C and a resistor R6, and has the same function as the case shown in FIG.

Moreover, since the off-state maintenance time does not change depending on the applied voltage, a more reliable starter operation can be expected than in the circuit shown in FIG.

Resistor R inserted in parallel with one of the diodes of the full-wave rectifier
7 is for producing the effects of D1 and D3 in FIG.

As explained above, according to the present invention, it is possible to reduce the size and weight of the phase advance type ballast, and furthermore, the lamp starting circuit can be easily configured.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional configuration of a phase-advanced discharge lamp lighting circuit, FIGS. 2 and 6 are circuit diagrams each showing an embodiment of the present invention, and FIGS. A curve diagram showing an example of the voltage-charge characteristics of a saturated nonlinear capacitor used in the invention, FIG. 4 is a waveform diagram for explaining the operation of the circuit according to the invention, and FIGS. FIG. 8, a circuit diagram showing another embodiment of the present invention, is a diagram showing operating waveforms of the starter circuit. In FIG. 1, B is a phase advance type ballast circuit, channel is an inductance, and C is a capacitor. L is a discharge lamp, and V1 is an AC power source. In FIG. 2, FC is a saturated nonlinear capacitor, in FIG. 6, L and T are magnetic leakage transformers, C1, C2, and C3 are capacitors, and L1 and L2 are preheating discharge lamps. In FIG. 7, S denotes a starter circuit, which is composed of a gate control switch FLS or SCR.

Claims (1)

[Scope of Claims] 1. A discharge lamp lighting circuit consisting of a series circuit of an AC power source, a discharge lamp, and a ballast circuit for the discharge lamp, wherein the ballast circuit is constituted by a series circuit of an inductance and a saturated nonlinear capacitor. A discharge lamp lighting circuit characterized by: 2. A discharge lamp lighting circuit according to claim 1, characterized in that a linear capacitor is connected in parallel with the nonlinear capacitor of the ballast circuit. 3. In the discharge lamp lighting circuit according to claim 1, a switch element or a switching element is provided in parallel with the discharge lamp, which turns off when the current finishes flowing, and turns off again after maintaining the off state for a predetermined period of time. A discharge lamp lighting circuit characterized by connecting circuits.