JP4645460B2 - Discharge lamp lighting device and lighting fixture - Google Patents

Description

  The present invention relates to a discharge lamp lighting device and a lighting fixture for lighting two discharge lamps connected in parallel to each other.

  2. Description of the Related Art Conventionally, there has been provided a discharge lamp lighting device that includes a power supply unit that outputs AC power and that simultaneously lights a plurality of discharge lamps connected in parallel to each other between output terminals of the power supply unit (for example, Patent Document 1). reference). Here, when the discharge lamps are simply connected in parallel to each other, the power supplied by the characteristics varies among the discharge lamps, so that the light output (that is, the luminance) varies between the discharge lamps. In particular, at the time of dimming lighting, there is a problem that the above-mentioned difference in luminance becomes larger as a ratio as the light output is reduced, so that it is noticeable. In addition, when only some of the discharge lamps are lit when starting the discharge lamp, the impedance of the lit discharge lamps decreases, so that the discharge lamps that did not illuminate cannot be lit without being supplied with sufficient voltage. It may disappear.

  As a method for solving the above problem, a method of using a balancer having two windings magnetically coupled to each other is known (for example, see Patent Document 1). An example of this type of discharge lamp lighting device is shown in FIG. This discharge lamp lighting device supplies high-frequency AC power to two discharge lamps La via a balancer T from a known half-bridge type inverter circuit to light them.

  The discharge lamp lighting device in FIG. 1 will be described in detail. This discharge lamp lighting device includes a series circuit of two switching elements Q1 and Q2 connected between output terminals of a DC power supply DC and one of the two switching elements Q1 and Q2 (in the example of FIG. A series circuit of a ballast choke L1 connected between both ends of the switching element Q2) and the resonance capacitor C1, and between the both ends of the resonance capacitor C1 by alternately turning on and off the two switching elements Q1 and Q2. And a drive control unit 1 for generating AC power. Each end of each winding of the balancer T is connected to a connection point between the ballast choke L1 and the resonance capacitor C1 via a DC cut capacitor C2. The other end of each winding of the balancer T is connected to the low voltage side terminal of the switching element Q1 on the low voltage side via different discharge lamps La.

  For example, as shown in FIG. 9, the balancer T has a cylindrical shape, and the winding portion B1 around which the windings N1 and N2 are wound in the circumferential direction and the axial direction of the winding portion B1 (the left-right direction in FIG. 9). A bobbin B made of an insulating material having a flange part B2 projecting in the radial direction of the winding part B1 at both ends, an E-type core EC having a middle leg inserted into the winding part B1 of the bobbin B, and E An I-type core IC that constitutes a Japanese-shaped closed magnetic path together with the mold core, and a gap paper Gp interposed between the E-type core EC and the I-type core IC.

  The drive controller 1 is supplied to each discharge lamp La by increasing or decreasing the frequency (hereinafter referred to as “operation frequency”) for turning on and off the switching elements Q1 and Q2 in accordance with a control signal input from the outside. Increase or decrease the power. That is, the switching elements Q1, Q2, the ballast choke L1, the resonance capacitor C1, the DC cut capacitor C2, and the drive control unit 1 constitute the power supply unit in the claims, and the drive control unit 1 It is also a control unit. The operating frequency is the output frequency of the power supply unit in the claims. Further, in each discharge lamp La, one end of one filament is connected to the balancer T, one end of the other filament is connected to the low voltage side terminal of the switching element Q1 on the low voltage side, and between the other ends of each filament. Is connected to a preheating capacitor (not shown).

  Here, a characteristic curve showing the relationship between the voltage between the filaments of the discharge lamp La and the operating frequency is shown in FIG. In FIG. 10, a curve a indicates a state where none of the discharge lamps La is lit, and a curve b indicates a state where both discharge lamps La are lit. Further, fr indicates the resonance frequency of the circuit connected between both ends of the switching element Q2 in the state of the curve a.

  When starting the discharge lamp La, the drive control unit 1 first has an operating frequency higher than the resonance frequency of the LC series resonance circuit including the ballast choke L1 and the resonance capacitor C1 over a predetermined preheating period. The power output between both ends of the resonance capacitor C1 is sufficient to preheat the discharge lamp La, and the voltage Vy between the filaments of the discharge lamp La does not start the discharge lamp La (so-called cold start). The preheating frequency fy is as follows. After the preheating period, the drive control unit 1 lowers the operating frequency so that the voltage applied between the filaments of the discharge lamp La becomes the starting frequency fs that becomes the voltage Vs at which the discharge lamp La starts. Then, each discharge lamp La is started and the impedance of each discharge lamp La is lowered, so that the characteristic curve becomes a curve b in FIG. Thereafter, each time a control signal instructing change of the dimming ratio is input, the drive control unit 1 changes the operating frequency according to the input control signal to change the power supplied to the discharge lamp La. As a result, the light output of the discharge lamp La is changed. At this time, the operating frequency is in a range higher than the resonance frequency of the entire circuit connected between both ends of the switching element Q2 including the discharge lamp La. Therefore, the light output is continuously increased as the operating frequency is increased. It becomes low. The upper limit value that can be taken by the operating frequency is, for example, the operating frequency at which each discharge lamp La is supplied with the minimum power that can be kept on.

In the above conventional example, the power supplied to each discharge lamp La is substantially equal to each other by the balancer T, and therefore the difference in light output between the discharge lamps La is small. Further, even when only one of the discharge lamps La was lit when starting the discharge lamp La, it was not lit due to the current flowing in the winding connected to the lit discharge lamp La among the windings of the balancer T. Since a current is induced in the winding connected to the discharge lamp La, it is possible to start the discharge lamp La that has not been lit by supplying sufficient power.
Japanese Patent No. 3291852

  By the way, when one of the discharge lamps La is in an abnormal state where it does not light, such as at the end of its life, the circuit between both ends of the switching element Q2 becomes as shown in FIG. Shows different characteristics from both the state of curve a where each discharge lamp La is turned off and the state of curve b where both discharge lamps La are turned on. A voltage applied to both ends of the discharge lamp La that is not lit in a state where only one discharge lamp La is lit is shown by a curve c in FIG. Further, fr ′ represents the resonance frequency of the circuit connected between both ends of the switching element Q2 in the state of the curve c. As can be seen from FIG. 10, in the state where only one of the discharge lamps La is lit, the voltage applied to both ends of the discharge lamp La that has not been lit is the case when none of the discharge lamps La is lit. It is higher than that. That is, a voltage higher than the voltage originally required for starting the discharge lamp La is applied between both ends of the discharge lamp La that has not been lit.

  Here, in order to sufficiently obtain the above effect by the balancer T, it is necessary to increase the mutual inductance of the balancer T, that is, to increase the self-inductance of each winding of the balancer T. However, when one of the discharge lamps La is in an abnormal state that does not light, such as at the end of its life as described above, the voltage Vs ′ applied between the filaments of the abnormal discharge lamp La after the normal discharge lamp La is lit is the balancer T The higher the self-inductance of each winding, the higher. For this reason, when the self-inductance of each winding of the balancer T is increased in order to reduce the difference in the optical output between the discharge lamps La, a circuit component to which a voltage corresponding to the voltage Vs ′ is applied correspondingly (for example, the discharge lamp La When a preheating capacitor is connected between the filaments, it is necessary to use an expensive part having a higher withstand voltage as the preheating capacitor), and the manufacturing cost is high.

  The present invention has been made in view of the above-described reasons, and its object is to provide a discharge lamp lighting device and an illumination that can reduce the load on the circuit when one of the discharge lamps connected in parallel to each other does not light up. To provide an instrument.

  According to the first aspect of the present invention, there is provided a power supply unit that outputs AC power, and a discharge lamp that is electrically connected at one end to one output end of the power supply unit and the other end is connected to the other output end of the power supply unit. A balance unit including at least a balancer having two windings that are electrically connected and magnetically coupled to each other, and a balance unit that balances power supplied to each discharge lamp, and a frequency of an output of the power supply unit is varied. And a control unit for controlling the light output of the discharge lamp, the resonance of the balance unit in a state where one end directly connected to the output end of the power supply unit is short-circuited in each winding of the balancer The balanced portion resonance frequency, which is the frequency, is set to 1.5 times or less of the frequency of the output of the power source when the discharge lamp is started.

  According to the present invention, when only one of the discharge lamps is turned on, the balanced part resonance frequency is set to be larger than 1.5 times the output frequency of the power supply unit at the time of starting the discharge lamp. The electric load applied to the circuit can be reduced by reducing the voltage applied between both ends.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the balanced portion resonance frequency is made larger than 0.8 times the upper limit value of the frequency of the output of the power supply portion.

  According to this invention, compared with the case where the balanced portion resonance frequency is 0.8 times or less of the upper limit value of the output frequency of the power supply unit, the discharge lamp between the discharge lamps when the output frequency of the power supply unit is set to the upper limit value. The difference in light output can be reduced.

  The invention of claim 3 is characterized in that, in the invention of claim 1 or claim 2, at least a part of each winding of the balancer is wound so as to be laminated alternately in the radial direction of the winding. .

  According to the present invention, at the time of designing, the design factor is the number of times each winding of the balancer is alternately stacked in the radial direction, thereby changing the parasitic capacitance between the windings of the balancer to achieve a desired balance. A part resonance frequency can be obtained.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the balance portion includes a capacitor portion made of conductors disposed in close proximity to each other and interposed between the windings of the balancer and the discharge lamp. It is characterized by having.

  According to the present invention, the parasitic capacitance between the conductors of the capacitive part is changed by designing the distance between the conductors constituting the capacitive part and the dimensional shape of the parts close to each other in each conductor during design. Thus, a desired balance part resonance frequency can be obtained.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the inductance value of each winding of the balancer is 5.0 mH or more.

  According to the present invention, the difference in light output between the discharge lamps can be reduced as compared with the case where the inductance value of each winding of the balancer is less than 5.0 mH.

  The invention of claim 6 has the discharge lamp lighting device according to any one of claims 1 to 5 and a socket that is electrically connected to the discharge lamp lighting device and mechanically and electrically connected to the discharge lamp. And an appliance main body for housing the discharge lamp lighting device.

  According to the present invention, one end is electrically connected to one output end of the power supply unit, and the other end is electrically connected to the other output end of the power supply unit via different discharge lamps and magnetically connected to each other. A balancer that includes at least a balancer having two windings coupled to each other and balances the electric power supplied to each discharge lamp, and one end directly connected to the output end of the power supply in each winding of the balancer Since the equilibrium part resonance frequency, which is the resonance frequency of the equilibrium part in a short-circuited state, is 1.5 times or less of the output frequency of the power supply part at the time of starting the discharge lamp, the equilibrium part resonance frequency is set to the power source at the time of starting the discharge lamp. Compared with a case where the frequency is higher than 1.5 times the output frequency of the part, when only one discharge lamp is lit, the voltage applied across the other discharge lamp is reduced to reduce the electrical load on the circuit. can do.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  Since the circuit configuration of this embodiment is common to the conventional example shown in FIG. 1, the same components are denoted by the same reference numerals, and illustration and description thereof are omitted.

  The present inventor has determined that the light output of the discharge lamp La is 5% of the rated lighting when the discharge lamp La is a straight tube type fluorescent lamp (FHF32) having a length of 4 ft (about 120 cm) and the ambient temperature is 0 ° C. The relationship between the self-inductance of each winding of the balancer T (hereinafter referred to as “balancer inductance”) and the luminance difference rate when the number of turns of each winding of the balancer T is changed is as follows. It investigated by measuring each brightness | luminance. Here, the luminance difference rate is a numerical value obtained by dividing the difference between the luminance of the two discharge lamps La having high luminance and the average luminance of the two discharge lamps La by the average luminance of the two discharge lamps La. (That is, a numerical value obtained by dividing the difference in luminance between the two discharge lamps La by the sum of the luminances of the two discharge lamps La) multiplied by 100. The results are shown in FIG. As can be seen from FIG. 2, the higher the balancer inductance, the lower the luminance difference rate, but the decrease rate increases when the balancer inductance is 5 mH or less. Based on this result, in this embodiment, the self-inductance of each winding of the balancer T is set to 5 mH or more. Thereby, compared with the case where the self-inductance of each winding of the balancer T is less than 5 mH, the difference in the light output between the discharge lamps La is small. As design elements related to the balancer inductance, in addition to the number of turns of each winding of the balancer T, in the case of the balancer T having the structure of FIG. 9, the thickness dimension of the gap paper Gp (that is, E type core EC and I type core IC) There is also a distance between.

In addition, the inventor connects the discharge lamp La only to one of the sockets to which the discharge lamp La is attached in the circuit of FIG. 1 and the other simulates a filament of the discharge lamp La (hereinafter referred to as “simulated filament”). In this case, only one of the discharge lamps La is connected, and the parasitic capacitance between the windings of the balancer T is increased between the ends of the windings of the balancer T near the discharge lamp La. For a circuit to which a capacitor imitating a capacitor (not shown; hereinafter referred to as “parasitic capacitance capacitor”) is connected, a ratio of a balanced portion resonance frequency fb to a starting frequency fs, which will be described later, and an operating frequency as a starting frequency fs are discharge lamps. The relationship between the voltage generated between the simulated filaments when La was turned on (hereinafter referred to as “stress voltage”) was examined by measurement. A graph with the former on the horizontal axis and the latter on the vertical axis is shown in FIG.

Note that the balanced portion resonance frequency fb is a state in which one end on the side away from the discharge lamp La in each winding of the balancer T is short-circuited, and between the other ends of each winding of the balancer T (that is, between both ends of the parasitic capacitor). The resonance frequency measured using an impedance analyzer in FIG. The starting frequency fs is constant at all measurement points, and the balanced portion resonance frequency fb is changed by changing the capacitance value of the parasitic capacitor.

As can be seen from FIG. 3, the stress voltage is clearly lower at the point where the ratio fb / fs of the balanced portion resonance frequency fb to the starting frequency fs is lower than about 1.5. On the contrary, when the ratio fb / fs is 1.8 or more, the stress voltage is close to 1000 V or 1000 V or more, which is higher than the voltage value necessary for starting the discharge lamp La. In this case, for example, the discharge lamp La When a preheating capacitor is connected between the filaments, it is necessary to use a relatively expensive capacitor having a high withstand voltage as the preheating capacitor. Based on this result, in this embodiment, the ratio fb / fs to the starting frequency fs of the balanced portion resonance frequency fb is set to 1.5 or less. For example, when the starting frequency fs is 70 kHz, the balanced portion resonance frequency fb may be 105 kHz or less. This is because the parasitic capacitance between the windings of the balancer T is about 124 pF or more when the balancer inductance is 5 mH. Can be achieved.

  Here, when the parasitic capacitance between the windings of the balancer T is made larger than in the case of the curve c in FIG. 10, it is applied between both ends of the discharge lamp La that is not lit when only one discharge lamp La is lit. FIG. 4 shows a curve d showing the relationship between the voltage (that is, the stress voltage at the starting frequency fs) and the operating frequency added to FIG. Fr ″ indicates the resonance frequency of the circuit connected between both ends of the switching element Q2 in the state of the curve d. As can be seen from FIG. 4, the stress voltage Vs ″ in the state of the curve d in which the parasitic capacitance between the windings of the balancer T is larger than the stress voltage Vs ′ in the state of the curve c is reduced. Has been.

Further, the present inventor sets the ratio fb / fmax of the balanced portion resonance frequency fb to the upper limit value (hereinafter referred to as “maximum operating frequency”) fmax of the operating frequency as 0.6, 0.8, 2.0. In three different cases, the relationship between the current flowing between the filaments of the discharge lamp La (hereinafter referred to as “discharge lamp current”) and the luminance difference rate was examined. A graph with the former on the horizontal axis and the latter on the vertical axis is shown in FIG. In all three cases, the maximum operating frequency fmax is constant, and the ratio fb / fmax is changed by changing the balanced portion resonance frequency fb as in the case of FIG. Incidentally, in the case of the FHF 32 used in the present embodiment, the light output when the discharge lamp current is 20 mA is about 5% of the rated lighting. In FIG. 5, a curve e indicates a case where the ratio fb / fmax is 0.6, a curve f indicates a case where the ratio fb / fmax is 0.8, and a curve g indicates the ratio fb / fmax. Is 2.0. As can be seen from FIG. 5, when the discharge lamp current is the minimum, that is, when the operating frequency is the maximum operating frequency fmax, the luminance difference ratio is the ratio fb / of the balanced portion resonance frequency fb to the maximum operating frequency fmax. When fmax is 0.6, it exceeds 25%, but when it is 0.8, it rapidly decreases to 15% or less. Based on this result, in this embodiment, the ratio fb / fmax of the balanced portion resonance frequency fb to the maximum operating frequency fmax is set to be larger than 0.8. For example, when the maximum operating frequency fmax is 100 kHz, the balanced portion resonance frequency fb may be higher than 80 kHz. If the balancer inductance is 5 mH, the parasitic capacitance between the windings of the balancer T is less than about 198 pF. Can be achieved. Thereby, in this embodiment, the difference of the light output (luminance) between discharge lamps is small compared with the case where ratio fb / fmax of the balance part resonance frequency fb with respect to the maximum operating frequency fmax is 0.8 or less. .

Moreover, the effect when the operating frequency becomes equilibrium portion resonance frequency fb is to reduce the difference in light output between the discharge lamp La by the balancer T fades, it does not include balancing unit resonance frequency fb to a possible range operating frequencies Thus, it is desirable that the balanced portion resonance frequency fb is higher than the maximum operating frequency fmax, for example.

Here, in order to adjust the balanced portion resonance frequency fb in order to satisfy the above-described conditions regarding fb / fs and fb / fmax, by adjusting the number of times the winding is alternately wound in the radial direction in the balancer T, The parasitic capacitance between the windings of the balancer T may be adjusted. For example, if the windings N1 and N2 of the balancer T are alternately wound twice in a total of four layers as shown in FIG. 6 (a), each winding N1 and N2 is individually divided into a total of two layers as shown in FIG. Since the parasitic capacitance between the windings N1 and N2 of the balancer T is larger than the case where the balancer T is wound around, the capacitance value in the balanced portion can be increased. Furthermore, as shown in FIG. 6 (b), if the windings N1 and N2 are alternately wound in five layers or more, the capacitance value in the balanced portion can be further increased. Thus, as the number of turns of each winding of the balancer T alternately in the radial direction is increased, the capacitance value in the balancing section can be increased and the balancing section resonance frequency fb can be reduced.

According to the above configuration, by setting the ratio fb / fs to the starting frequency fs of the balanced portion resonance frequency fb to be 1.5 or less, compared with the case where the ratio fb / fs is larger than 1.5, When only the discharge lamp La is lit, the stress voltage applied between the filaments of the other discharge lamp La is reduced, thereby reducing the electrical load on the circuit components to which the voltage corresponding to the stress voltage is applied. Therefore, for example, even when a preheating capacitor is connected between the filaments of the discharge lamp La, the manufacturing cost can be reduced by using an inexpensive preheating capacitor having a low withstand voltage.

  As shown in FIG. 7, instead of the direct current cut capacitor C2, direct current cut capacitors C2a and C2b each having a capacitance value that is half the capacitance value of the direct current cut capacitor C2 are connected to the windings of the balancer T. And the discharge lamp La may be connected to each other.

Further, the conductors interposed between the windings of the balancer T and the discharge lamp La (between the DC cutting capacitors C2a and C2b and the discharge lamp La in the circuit of FIG. 7) as parallel portions are arranged in parallel with each other. A capacitor portion that is arranged close to may be added. By adopting this configuration, the balanced portion resonance frequency fb can be adjusted by adjusting the length of the capacitance portion and the distance between the conductors in the capacitance portion. For example, an electric wire generally used in a discharge lamp lighting device is used as a conductor between each winding (or each DC cut capacitor C2a, C2b) of the balancer L and the discharge lamp La, and these electric wires are brought into close contact with each other. When the capacitor unit is configured in parallel, the capacitance value of the capacitor unit is about 50 pF per 1 m length.

  Further, the power supply unit is not limited to the half-bridge type inverter circuit as in the present embodiment as long as it is a circuit that outputs alternating current power, and other well-known inverter circuits such as a full-bridge type and a one-stone voltage resonance type, for example. May be used.

  In the present embodiment, for example, as shown in FIG. 8, there are two sets of four sockets S to which the terminals of the straight tube type discharge lamp La are mechanically and electrically connected, and are fixed to the ceiling surface. It is housed in the fixture body H and constitutes a lighting fixture. This lighting fixture is a general Fuji-mountain lighting fixture for two lamps, and two discharge lamps La are mounted on the socket S side by side in the radial direction of the discharge lamp La and along the ceiling surface. The appliance main body H has a triangular prism shape such that a cross-sectional area in a cross section orthogonal to the length direction of the discharge lamp La becomes an isosceles triangle having a vertex downward. Each downward surface of the appliance body H is painted, for example, in white and directed toward the discharge lamp La, and distributes light of La such as discharge.

It is a circuit diagram which shows an example of a discharge lamp lighting device. Is an explanatory view showing the relationship between the self-inductance and the luminance difference ratio of each winding of the balancer. For the starting frequency of the balancing portion resonance frequency is an explanatory diagram showing the relationship between the ratio and the stress voltage. Is an explanatory view showing the relationship between the voltage and the operating frequency that occurs between the filaments of the discharge lamp. It is explanatory drawing which shows the relationship between a discharge lamp electric current and a brightness | luminance difference rate about three cases which each changed the balance part resonance frequency. (A) (b) is explanatory drawing which shows the structure of the balancer in embodiment of this invention, respectively, (a) (b) shows the example which each varied the frequency | count of winding a coil | winding. It is a circuit diagram which shows another example of the circuit of a discharge lamp lighting device. It is a perspective view which shows an example of the lighting fixture by which this embodiment is used. It is explanatory drawing which shows an example of the structure of a balancer. Is an explanatory view showing the relationship between the voltage and the operating frequency that occurs between the filaments of the discharge lamp. It is a circuit diagram which shows the principal part of the discharge lamp lighting device in the state where only one of the discharge lamps is lit.

Explanation of symbols

1 Drive Control Unit H Instrument Body La Discharge Lamp S Socket T Balancer

Claims (6)

A power supply unit that outputs AC power, and one end of which is electrically connected to one output end of the power supply unit and the other end is electrically connected to the other output end of the power supply unit via different discharge lamps A balance unit that includes at least a balancer having two windings magnetically coupled to each other and balances the power supplied to each discharge lamp, and the light output of the discharge lamp by varying the output frequency of the power supply unit A discharge lamp lighting device comprising a control unit for controlling
In each winding of the balancer, the balanced portion resonance frequency, which is the resonance frequency of the balanced portion in a state where one end directly connected to the output end of the power supply portion is short-circuited, is 1. A discharge lamp lighting device characterized by being 5 times or less.   2. The discharge lamp lighting device according to claim 1, wherein the balanced part resonance frequency is set to be greater than 0.8 times the upper limit value of the output frequency of the power supply part.   3. The discharge lamp lighting device according to claim 1, wherein at least a part of each winding of the balancer is wound so as to be alternately laminated in the radial direction of the winding.   The discharge lamp lighting according to any one of claims 1 to 3, wherein the balancing portion includes a capacitor portion made of conductors disposed in close proximity to each other and interposed between each winding of the balancer and the discharge lamp. apparatus.   The discharge lamp lighting device according to any one of claims 1 to 4, wherein an inductance value of each winding of the balancer is set to 5.0 mH or more.   A discharge lamp lighting device according to any one of claims 1 to 5, and a socket that is electrically connected to the discharge lamp lighting device and mechanically and electrically connected to the discharge lamp lighting device, and stores the discharge lamp lighting device. A lighting fixture comprising: a lighting fixture body.

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