JPS6337957B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a discharge lamp lighting device that is capable of lighting a saturated vapor type high-pressure discharge lamp such as a high-pressure sodium lamp at a high power factor using an AC power source containing high frequencies. AC power supply circuits including rotary rectifiers and transformers often contain odd-order harmonics in addition to commercial frequencies. When a high-pressure discharge lamp such as a high-pressure mercury lamp is lit using such an AC power supply through a ballast equipped with a power factor correction capacitor, the harmonics contained in the AC power supply cause excessive damage to the power factor correction capacitor. An accident occurs where current flows and the capacitor is destroyed. Therefore, conventionally, when lighting a high-pressure discharge lamp with an AC power supply containing harmonics, a phase-advancing type ballast is used, which is a constant-power type or a frizzless type discharge lamp, and a phase-advancing capacitor is connected in series with the discharge lamp. or a slow-phase ballast consisting only of an inductor was used. However, recently, high-pressure sodium lamps with higher luminous efficiency and better color rendering have become popular in place of high-pressure mercury lamps, and when trying to light these discharge lamps with an AC power source that contains harmonics, the above-mentioned progress has been made. If a phase type ballast is used, stable lighting cannot be achieved, and if a slow phase type ballast is used, high power factor lighting cannot be achieved. The reason why a high-pressure sodium lamp cannot be lit stably using a phase-advancing ballast is because a high-pressure sodium lamp is a saturated vapor-type high-pressure discharge lamp, and due to the constant current action of the ballast, the lamp voltage is lower. , because the higher the value, the higher the characteristic that changes, resulting in a large change in lamp power. Another reason is that when a saturated vapor type high pressure discharge lamp is lit with a phase advance type ballast, the lamp current waveform deteriorates, the current pause period becomes longer, and the restriking voltage becomes significantly higher. The present invention has been made in view of the above points, and it is possible to stably light a saturated vapor type high pressure discharge lamp such as a high pressure sodium lamp with a high power factor using an AC power source containing harmonics. The object of the present invention is to provide a discharge lamp lighting device. As shown in FIG. 1, the discharge lamp lighting device according to the present invention comprises a series circuit of an AC power source E containing harmonics, a current limiting inductor CH ₂ such as a chiyoke coil, and a saturated vapor type high pressure discharge lamp L such as a high pressure sodium lamp. and connect a series circuit of inductor CH ₁ and capacitor C in parallel with the series circuit,
The values of the inductor CH ₁ and capacitor C and the relationship between them are selected as follows. That is, first, the combined impedance of the inductor CH ₁ and the capacitor C is selected so that it is on the leading side with respect to the commercial frequency and on the lagging side with respect to third-order or higher odd harmonic frequencies. That is, the capacitor C improves the lagging power factor caused by the current limiting inductor _CH2 , and the inductor _CH1 eliminates the influence of harmonics on the capacitor C. Second, the values of the inductor CH ₁ and capacitor C are adjusted so that the power factor lags behind the commercial frequency and falls within the range of 90%, so that the primary power factor becomes a high power factor of 85% or more. Select. This allows the saturated steam type high pressure discharge lamp to be lit at a high power factor. Third, the resonance frequency of the inductor CH ₁ and the capacitor C is selected to be 1.1 times to 2.0 times the commercial frequency. This takes into account the total impedance for the fundamental frequency and odd harmonics, and it goes without saying that this value should not be less than the fundamental frequency, and if it exceeds 2.0, it will be susceptible to the effects of odd harmonics. Because it will be. Next, a design example of a discharge lamp lighting device according to the present invention will be explained. Now, a high-pressure sodium lamp with a rated lamp power of 360 W is loaded on a 50 Hz/200 V commercial AC power supply, and when there is no load (Fig. 2 C), when the load is short-circuited (Fig. 2 A), and when the load is lit (Fig. 2). Suppose we want to obtain various characteristic values as shown in the table below for each of B).

[Table] In the above table, V ₁ is the power supply voltage, V ₀₂ is the secondary no-load voltage, P ₁ is the primary input power during lighting, PF ₁ is the primary power factor, Vl is the lamp voltage, and Pl is the lamp power. be. I _C , I _S1 , I _S2 , I ₁ and Il are respectively shown in Figure 2A.
- Current flowing through each part of the circuit shown in FIG. 2C. A high-pressure sodium lamp with a rated power of 360W is powered at 50Hz through an inductor such as a chiyoke coil.
When lit with a 200V power supply, its primary power factor lags.
At 60% the lamp current Il is 3.3A. This can be expressed as a vector diagram as shown in Figure 3. From the same figure, the capacitor current I _C at no load is found to be 2.6A. Based on this current value, the values of inductor CH ₁ and capacitor C in Figure 1 are found as follows: 2.6 (X _C - X _L ) = 200 (X _C and X _L are the resistance values of the capacitor and inductor, respectively) (X _C - X _L ) = 77 [Ω] Here, if the work voltage of capacitor C is considered and the capacitance of the capacitor C is selected to an arbitrary value, for example 25 μF, then X _C = 1/2π _C = 1/2π × 50 ×25×10 ^-6 = 127 [Ω] X _L = 127−77 = 50 [Ω _] L =
] becomes. The resonant frequency r in this case is This is 1.57 times the commercial frequency of 50Hz.
Also, X _L for the third harmonic frequency 150Hz,
X _C = 127/3 = 42.3 [Ω] X _L = 50 x 3 = 150 [Ω], so _{X L} is larger than X _C , and it becomes a lagging impedance with respect to the third harmonic. That is, by selecting the values of the inductor CH ₁ and the capacitor C as described above, all of the above conditions are satisfied, and various characteristics as shown in the table and relationships as shown in the vector diagram can be obtained. Note that when the primary power factor is set on the leading side, I _C becomes large, I _S1 becomes small, and the inductor CH ₁ becomes large. On the other hand, if the primary power factor is set to the lagging side, I _C becomes small, I _S1 becomes large, and the inductor CH ₁ becomes small. In addition, the primary power factor is 90% of the commercial frequency.
If it is set to the delay side below, the high power factor range of 85% or more may be exceeded due to the delay current of the harmonic current. FIG. 4 shows another embodiment of the present invention, A
is an example in which a circuit similar to that shown in Figure 1 is connected to the secondary side of the transformer Tr, B is an example in which a discharge lamp is connected to a 100V power supply via a leaky transformer Tr', and C is an example in which a leaky transformer Tr is connected to a 200V power supply. ' In the case of B and C, windings L ₁ and L ₂ are connected to the first
Corresponds to CH ₂ and CH ₁ in the circuit shown. As is clear from the above description, according to the present invention, a series circuit of an inductor and a capacitor is connected in parallel with a series circuit of a current-limiting inductor and a discharge lamp, and the values of the inductor and capacitor are set under certain conditions. A great advantage is that a saturated vapor type high-pressure discharge lamp such as a high-pressure sodium lamp can be operated stably and at a high power factor using an AC power source containing harmonics by simply selecting an appropriate method. be.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a discharge lamp lighting device according to the present invention, Fig. 2 is a circuit diagram for explaining the circuit current associated with the load state of the device, and Fig. 3 shows the relationship between the circuit currents in the device. The vector diagram and FIG. 4 are circuit diagrams of other embodiments of the present invention. In Figure 1 or Figure 4, E...AC power supply containing harmonics, L...Saturated vapor type high pressure discharge lamp, CH
1... Inductor, CH2... Current limiting inductor,
C...Capacitor, Tr, Tr'...Transformer.

Claims (1)

[Claims] 1 A series circuit of a current-limiting inductor and a saturated vapor high-pressure discharge lamp is connected to an AC power source containing harmonics, and a series circuit of an inductor and a capacitor is connected in parallel with the series circuit, and the inductor of the series circuit is The combined impedance of the capacitor and capacitor is selected to be on the leading side for commercial frequencies and on the lagging side for odd harmonic frequencies, and the primary power factor at commercial frequencies is in the range of 90% lagging to 90% leading. A discharge lamp lighting device for a power supply containing harmonics, characterized in that the values of the inductor and capacitor are selected so that the values of the inductor and capacitor are such that the resonant frequency of the inductor and capacitor is selected to be in the range of 1.1 times to 2.0 times the commercial frequency.