JP2001135488A - Lighiting device for internal-combustion engine driving discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide alighting device for internal-combustion engine driving discharge lamps which can prevent that the life of elements constituting the device is reduced by the continuous generation of high-tension pulses at an unlighted time of the discharge lamp. SOLUTION: A pulse-generation circuit 14 is provided to generate high-voltage pulses Vp by using a generator 12 driven by an internal-combustion engine as a power source, and the high-voltage pulses Vp are impressed to a discharge lamp 13, over lapping the output voltage of the generator 12. A generator with suspension characteristics is used as the generator 12. A timer circuit 17 which starts a timing action when the generator 12 comes into the condition to generate high-voltage pulses is provided, and when the timer circuit 17 completes the timing action, the output of high-voltage pulses from the pulse-generation circuit 14 is suspended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine driven discharge lamp lighting device used for lighting a high pressure discharge lamp such as a high pressure mercury lamp, a metal halide lamp or a high pressure sodium lamp.

[0002]

2. Description of the Related Art A synchronous generator driven by an internal combustion engine is used as a power supply device for lighting a lighting device used at a construction site, a lighting device for leisure, or a lighting device for disaster prevention. . In recent years, discharge lamps such as mercury lamps have been increasingly used in place of incandescent lamps as lighting equipment for construction sites and lighting equipment for leisure.

As is well known, a discharge lamp has a negative impedance characteristic, and once discharge starts, the impedance decreases with an increase in current. Therefore, if the current is not limited, the discharge current is unlimited. And it is destroyed. Therefore, in the conventional discharge lamp lighting device, a magnetic leakage transformer or a ballast having a choke coil is provided between the power supply and the discharge lamp, and the power supply voltage is applied to the discharge lamp through the magnetic leakage transformer or the choke coil. ing.

When a high-pressure discharge lamp such as a high-pressure mercury lamp or a metal halide lamp is turned on, it is necessary to apply a high voltage to both ends of the discharge lamp when starting the discharge lamp. A circuit is provided.

As described above, in the conventional discharge lamp lighting device widely used, a ballast is required in addition to the generator. However, since the ballast has an inductive load and has a low power factor, the ballast is required. It was inevitable that the load on the generator would be increased if the device was provided. In addition, if a ballast is provided between the generator and the discharge lamp, the ballast also acts as a load on the generator, so that only a lamp load of about 1/2 to 1/3 of the generator rating can be driven. In addition, there is a problem that a large-capacity generator must be used, which increases the cost.

Accordingly, the present applicant sets the short-circuit current of the generator so as to limit the discharge current immediately after the start of discharge of the discharge lamp to an allowable value or less, using a generator having drooping characteristics. By setting the output voltage vs. output current characteristics of the generator so that the terminal voltage and discharge current of the discharge lamp in the steady state are kept within the rated ranges, the discharge lamp is turned on without using a ballast. A lighting device was proposed.

If the no-load output voltage of the generator can be made higher than the discharge starting voltage of the discharge lamp, the output voltage versus output current characteristic of the generator is set to a drooping characteristic as described above, and The discharge lamp can be turned on only by directly applying the output voltage to the discharge lamp. However, when lighting a high-pressure discharge lamp, the no-load output voltage of the generator cannot be higher than the discharge starting voltage of the discharge lamp. Cannot be turned on.

As an example, consider the case of lighting a 400 [W] metal halide lamp. Assuming that the operating point of the metal halide lamp at steady state is set near the maximum output point of the generator, the no-load voltage of the generator is usually 200
[V] to about 300 [V]. However, since the discharge starting voltage of the metal halide lamp is 2000 [V] to 3000 [V], the discharge cannot be started if the output voltage of the generator is directly applied to the discharge lamp.

Therefore, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 10-699.
In No. 87, like metal halide lamps,
A lighting device using a generator having a drooping characteristic and a capacitor discharge type pulse generating circuit has been proposed as a lighting device for lighting a discharge lamp requiring a high voltage pulse at the time of starting.

FIG. 6 shows an example of the configuration of a previously proposed internal combustion engine drive discharge lamp lighting device. In FIG. 6, reference numeral 1 denotes an internal combustion engine, and 2 denotes a single-phase AC voltage driven by the internal combustion engine 1. The AC generator 3 is a high-pressure discharge lamp such as a metal halide lamp. Reference numeral 4 denotes a pulse generation circuit that generates a high-voltage pulse when the discharge lamp is started using the generator 2 as a power source, and 5 denotes a pulse generation control unit that controls generation and stop of the high-voltage pulse from the pulse generation circuit.

The illustrated pulse generation circuit 4 includes a primary coil W
1 and a step-up transformer 4A having a secondary coil W2, and a primary current control circuit 4 for controlling a primary current of the step-up transformer.
B and a high-voltage pulse W connected to the secondary coil W2 of the step-up transformer in parallel between the output terminals 2a and 2b of the generator 2.
A bypass capacitor 4C for bypassing a pulse current flowing when P occurs from the generator 2;
Power supply input terminals 4b1 and 4b2 of primary current control circuit 4B
Are connected to output terminals 2a and 2b of the generator 2, respectively. The output terminal 2a of the generator 2 is directly connected to one end of the discharge lamp 3, and the output terminal 2b of the generator is connected to a step-up transformer 4A.
Is connected to the other end of the discharge lamp 3 through the secondary coil W2.

Primary current control circuit 4B of pulse generation circuit 4
Causes a sudden change in the primary current of the step-up transformer 4A obtained by the output of at least one of the positive and negative half cycles of the output of the generator 2 to induce a high voltage pulse Vp in the secondary coil W2 of the transformer. Let it. This high voltage pulse Vp is superimposed on the output voltage Ve of the generator 12 and applied to the discharge lamp 3.

The pulse generation control means 5 includes an element which generates heat with the generation of a high-voltage pulse among the elements constituting the pulse generation circuit 4, such as a step-up transformer 4A or a switch element for interrupting the primary current of the step-up transformer. The temperature is detected, and the pulse generation circuit 4 is controlled so that the generation of the high-voltage pulse is stopped when the detected temperature exceeds the set temperature.

The primary current control circuit 4B includes, for example, a step-up transformer that includes a pulse generating capacitor charged by the output voltage of the generator 2 and a discharge switch that discharges the charge of the capacitor through the primary coil W1 of the step-up transformer 4A. 4 is provided on the primary side, and a high voltage pulse is generated in the secondary coil of the step-up transformer by flowing the discharge current of the capacitor to the primary coil of the step-up transformer.

As described above, in the proposed internal combustion engine drive discharge lamp lighting device using the generator having the drooping characteristic and the capacitor discharge type pulse generation circuit, the high voltage pulse Vp generated by the pulse generation circuit 4 is used. As a result, the discharge lamp 3 starts discharging. When the discharge lamp 3 is started, a load current flows through the generator 2, so that the output voltage of the generator decreases according to the drooping characteristic. Stop the occurrence of

[0016]

As described above, when the internal combustion engine driving discharge lamp lighting device is configured by using the generator 2 having the drooping characteristic and the capacitor discharge type pulse generating circuit 4, a ballast is used. The high pressure discharge lamp can be turned on without any trouble. However, with the already proposed lighting device,
When the lit discharge lamp 3 is turned off (open state) due to the life of the discharge lamp, an accident, or the like, the pulse generation circuit 4 becomes in a state of continuously generating a high-voltage pulse, and this state is left unattended. In this case, there is a problem that the life of the elements constituting the device is shortened.

An object of the present invention is not only to be able to light a high-pressure discharge lamp such as a high-pressure mercury lamp or a metal halide lamp without using a ballast composed of a magnetic leakage transformer, but also to turn on the discharged lamp for some reason. An object of the present invention is to provide an internal combustion engine drive discharge lamp lighting device in which a pulse generation circuit does not continue to generate a high voltage pulse when a non-lighting state is caused, thereby not adversely affecting the life of the element.

[0018]

SUMMARY OF THE INVENTION The present invention comprises an internal combustion engine,
A generator driven by the internal combustion engine to output a voltage for driving the discharge lamp, and a pulse generation circuit for generating a high-voltage pulse for starting the discharge lamp using the generator as a power source. The present invention is directed to an internal combustion engine driven discharge lamp lighting device that lights the discharge lamp by superimposing the output of the pulse generation circuit and applying the output to the discharge lamp.

The above-mentioned pulse generating circuit is configured to output a high voltage when the generator outputs a voltage higher than a set level higher than an output voltage value of the generator when a rated discharge current is flowing through the discharge lamp. It is configured to generate a pulse.

The generator is configured so that the output voltage-output current characteristic exhibits a drooping characteristic, and the short-circuit current of the generator is set so as to limit the discharge current immediately after the discharge lamp starts to be discharged to an allowable value or less. At the same time, the output voltage-output current characteristics of the generator are set so that the terminal voltage and the discharge current of the discharge lamp in the steady state are kept within the rated ranges.

The drooping characteristic of a generator is a characteristic in which the output voltage rapidly decreases with an increase in the output current of the generator and the output current is limited to a certain value or less. The number of turns of the armature windings of the rotor and the magnetic poles of the rotor and the stator are increased so that the leakage magnetic flux flowing through the adjacent magnetic pole when the magnetic pole of the rotor and the magnetic pole of the stator face each other is increased. It can be easily obtained by adjusting the arc.

According to the present invention, a timer circuit for starting a timed operation when the pulse generating circuit generates a high voltage pulse, and the generation of the high voltage pulse is permitted while the timer circuit is performing the timed operation. And a pulse generation circuit control means for controlling the pulse generation circuit so as to inhibit the generation of the high voltage pulse when the timer circuit completes the timed operation.

In the above-described discharge lamp lighting device, when the output voltage is turned on after the internal combustion engine is started and the output of the generator is established, the timer circuit starts timed operation. Since the pulse generating circuit generates a high-voltage pulse while the timer circuit is performing the timed operation, the high-voltage pulse is applied to the discharge lamp. Since the terminal voltage of the discharge lamp exceeds the discharge start voltage by the application of the high voltage pulse, the discharge lamp starts discharging.

When the discharge lamp starts discharging, its impedance rapidly decreases, and the output voltage of the generator becomes lower than the set level. Therefore, the pulse generation circuit stops generating high-voltage pulses, and the timer circuit Also stop the timed operation.

The discharge current immediately after the discharge lamp starts to discharge increases as the short-circuit current of the generator increases.
In the present invention, the magnitude of the short-circuit current of the generator is set so that the output current versus the output current characteristic of the generator is set as a drooping characteristic, and the discharge current immediately after the start of the discharge is limited to a value less than or equal to an allowable value for the discharge lamp. For setting, the discharge current immediately after the start of discharge is limited to an allowable value or less.

When the temperature of the discharge lamp increases after the discharge lamp has started discharging, the internal impedance gradually increases, so that the discharge current gradually decreases. When the discharge lamp is in a thermally stable state (steady state), the discharge lamp is stabilized at the intersection of the impedance curve of the discharge lamp and the output voltage versus output current characteristic curve of the generator.

In the present invention, the output voltage versus output current characteristic of the generator is set so that the voltage and discharge current at both ends of the discharge lamp in the steady state fall within the rated range of the discharge lamp. After the engine is started, it can be shifted to a steady state and can be stably turned on.

When the discharge lamp is on, the output voltage of the generator is lower than the set level, so that the pulse generation circuit stops generating high-voltage pulses. The timer circuit also stops timed operation.

It is assumed that the discharge lamp that has been lit due to the life of the discharge lamp, an accident, or the like has become unlit. At this time, the impedance of the discharge lamp increases, and the output voltage of the generator rises to its no-load voltage. Therefore, the pulse generating circuit generates a high-voltage pulse, and at this time, the timer circuit simultaneously starts timed operation. Thereafter, when the timed operation of the timer circuit is completed, the pulse generation circuit control means prohibits the generation of the high voltage pulse.

Therefore, when the discharge lamp is turned off, it is possible to prevent the high-voltage pulse from being generated for a long time, thereby preventing the insulation life of the elements constituting the device from being shortened.

The high-pressure discharge lamp becomes hot when it is in a lighting state. When re-lighting a discharge lamp that has been turned off from a lighting state, if the temperature of the discharge lamp is high, the discharge lamp cannot be re-lit even if a normal high-voltage pulse is applied.
Therefore, after turning off the light, when re-lighting the discharge lamp which is still in a high temperature state (re-lighting the discharge lamp when hot),
After turning on the output of the generator, it is necessary to continue to generate high-voltage pulses until the temperature of the discharge lamp decreases. Therefore, the time during which the timer circuit performs the timed operation (set time) is a minimum length necessary to relight the discharge lamp when hot (the discharge lamp temperature is turned on by the high voltage pulse generated by the pulse generation circuit). (A minimum length necessary to lower the temperature to a temperature at which the temperature can be reduced).

If the set time for the timer circuit to perform the timed operation is set as described above, the discharge lamp is turned off once, and when the discharge lamp is turned on again at a high temperature, the discharge lamp is turned off. Since the timer circuit is allowed to perform a timed operation until the temperature of the discharge lamp decreases, the generation of the high voltage pulse can be continued.

As the pulse generation circuit, a step-up transformer, a pulse generation capacitor provided on the primary side of the step-up transformer, and a capacitor charging circuit for charging the pulse generation capacitor to one polarity by an output voltage of the generator. A discharge switch provided to discharge the charge of the pulse generating capacitor through the primary coil of the step-up transformer when conducting, and the output voltage of the generator is lower than the output voltage of the generator at no load. When the output voltage of the generator reaches a set level which is lower and higher than the output voltage of the generator when the rated discharge current is flowing through the discharge lamp, a trigger signal is supplied to a trigger signal input terminal of the discharge switch to perform the discharge. And a discharge switch trigger circuit for turning on the switch. Can be used which is constituted of a high voltage pulse of magnitude required for the voltage applied to the lamp than the discharge starting voltage so as to induce in the step-up transformer secondary coil.

In this case, the output voltage of the generator is applied to the discharge lamp through the secondary coil of the step-up transformer.

In the case where the present invention is applied to a discharge lamp lighting device using the above-described pulse generation circuit, the trigger signal of the discharge switch of the pulse generation circuit is supplied from the discharge switch circuit to the bypass circuit when the discharge lamp lighting device is turned on. A trigger signal side switch is provided. Also, a timer power supply circuit that outputs a timer driving DC voltage when the generator outputs a voltage exceeding the set level, and a timed operation that starts timed operation when the timer power supply circuit outputs a constant DC voltage. A timer circuit for controlling the trigger signal side switch so as to hold the trigger signal side switch in a cutoff state while performing the timed operation and to conduct the trigger signal side switch when the timed operation is completed; Is provided.

When an AC generator is used as the generator, the pulse generating capacitor is charged by the output of one half cycle of the generator, and the trigger signal for the discharge switch is supplied to the other of the generator. Can be configured to be performed by the output of a half cycle.

When an alternator is used as a generator and a thyristor is used as a discharge switch, a trigger signal is given to the thyristor when the output voltage of the other half cycle of the generator reaches a set level, and the thyristor is turned on. The trigger circuit can be configured so as to conduct.

[0038]

1 shows an example of the configuration of an internal combustion engine drive discharge lamp lighting apparatus according to the present invention. In FIG. 1, reference numeral 11 denotes an internal combustion engine, and 12 denotes a single phase driven by the internal combustion engine 11. An AC generator for generating an AC voltage, 13 is a high-pressure discharge lamp such as a metal halide lamp, 14 is a pulse generation circuit that generates a high-voltage pulse when the discharge lamp is started using the generator 12 as a power supply, and 15 is a high-voltage pulse from the pulse generation circuit. This is pulse generation control means for controlling generation and stop of the voltage pulse.

The pulse generating circuit 14 includes a step-up transformer 14A having a primary coil W1 and a secondary coil W2, and a primary current control circuit 14 for controlling the primary current of the step-up transformer.
B and a pulse current which is connected in parallel between the output terminals 12a and 12b of the generator 12 and flows when the high voltage pulse VP is generated in the secondary coil W2 of the step-up transformer.
2 and a bypass capacitor 14C that bypasses the second capacitor 2C.

Power input terminal 1 of primary current control circuit 14B
4b1 and 14b2 are output terminals 1 of the generator 12, respectively.
2a and 12b. The output terminal 12a of the generator 12 is directly connected to one end of the discharge lamp 13, and the output terminal 12b of the generator is connected to the secondary coil W2 of the step-up transformer 14A.
Through the other end of the discharge lamp 13.

Primary current control circuit 1 of pulse generation circuit 14
4B suddenly changes the primary current of the step-up transformer 14A obtained by the output of at least one of the positive and negative half cycles of the output of the generator 12, and applies the high voltage pulse Vp to the secondary coil W2 of the transformer. Induce. This high voltage pulse Vp is superimposed on the output voltage Ve of the generator 12 and applied to the discharge lamp 13.

The pulse generation control means 15 includes an element (a step-up transformer 14A or a switch element for interrupting the primary current of the step-up transformer) which generates heat when a high-voltage pulse is generated among the elements constituting the pulse generation circuit 14. The temperature is detected, and the pulse generation circuit 14 is controlled so that the generation of the high voltage pulse Vp is stopped when the detected temperature exceeds the set temperature.

The above arrangement is the same as that of the conventional discharge lamp lighting device shown in FIG.
A timer power supply circuit 16 that outputs a timer driving DC voltage when the output voltage of the timer exceeds a set level; and a timer circuit 17 that starts timed operation when the timer power supply circuit 16 outputs the timer driving DC voltage. The pulse generation circuit 14 allows the pulse generation circuit 14 to generate a high voltage pulse while the timer circuit 17 performs the timed operation, and the pulse generation circuit 14 generates the high voltage pulse when the timer circuit 17 completes the timed operation. And a pulse generation circuit control means (not shown in FIG. 1) for controlling the pulse generation circuit 14 so as to prohibit the operation.

FIG. 2 shows a specific configuration example of each part of the discharge lamp lighting device of FIG. In FIG. 2, reference numeral 14 denotes a pulse generation circuit including a step-up transformer 14A, a primary current control circuit 14B, and a bypass capacitor 14C;
5 is a pulse generation control means, 16 is a power supply circuit for a timer, 1
7 is a timer circuit, and 18 is a pulse generation circuit control means.

In this example, a magnet type AC generator including a magnet rotor and a stator having an armature coil is used as the generator 12, and an AC voltage can be obtained from the generator 12. ing.

The step-up transformer 14A includes an iron core F, and a primary coil W1 and a secondary coil W2 wound around the iron core. One end of the primary coil W1 is connected to one end of a pulse generating capacitor C1, and the other end of the capacitor C1 is connected to the cathode of a diode D1. The anode of the diode D1 is connected to one output terminal 12a of the generator 12 through the switch SW. Primary coil W
The other end of 1 is connected to the other output terminal 12b of the generator through a diode D2 with the anode facing the other end of the primary coil.

The other end of the capacitor C1 and the primary coil W1
The other end is connected to the anode and cathode of the thyristor SCR1, respectively, and a resistor R1 and a capacitor C2 are connected in parallel between the gate and cathode of the thyristor SCR1. The anode of the diode D3 is connected to the other output terminal 12b of the generator 12, and a resistor voltage dividing circuit composed of a series circuit of resistors R2 and R3 is connected between the cathode of the diode D3 and the line connected to the cathode of the thyristor SCR1. Have been. The voltage dividing point of this voltage dividing circuit is connected to the gate of the thyristor SCR1 through a Zener diode ZD1 with the cathode directed toward the voltage dividing point. The cathode is connected between the line connected to the cathode of the thyristor SCR1 and the other end of the switch SW having one end connected to one output terminal 12a of the generator 12.
A diode D4 directed to the side 2a is connected, and a diode D5 in the direction opposite to the thyristor is connected in parallel between the anode and cathode of the thyristor SCR1. The diode D5 is provided to regenerate energy stored in the primary coil of the step-up transformer 14A to the capacitor C1.

The gate and the cathode of the thyristor SCR1 are connected to the collector and the emitter of an NPN transistor TR1 constituting the pulse generation circuit control means 18, respectively, and are supplied through the Zener diode ZD1 when the transistor TR1 is in a conductive state. The trigger signal of the thyristor SCR1 is bypassed from the thyristor.

The timer power supply circuit 16 includes a diode D6 having an anode connected to one output terminal 12a of the generator 12 via a switch SW, an anode connected to the other output terminal 12b of the generator 12, and a cathode Comprises a series circuit of resistors R4 and R5 connected between a diode D7 connected to the cathode of the diode D6, a common connection point of the cathodes of the diodes D6 and D7, and a common line L connected to the cathode of the thyristor SCR1. A resistor voltage dividing circuit, a voltage dividing point of the resistor voltage dividing circuit and a common line L
And a capacitor C3 connected between the resistors R4 and R4.
5, a PNP transistor TR2 having an emitter connected to a connection point (voltage division point), a Zener diode ZD2 having an anode connected to the common line L side between the base of the transistor TR2 and the common line L, and a transistor It comprises a resistor R6 connected between the emitter and the base of TR2, and a capacitor C4 connected between the collector of the transistor TR2 and the common line L.

The timer circuit 17 includes a timer IC 17A
And resistors R7 and R7 externally connected to the timer IC 17A to determine the oscillation frequency of the oscillator in the timer IC 17A.
8 and a capacitor C5.

In the example shown in FIG. 2, the generator 12 → switch SW → diode D1 → capacitor C1 → primary coil W1 → diode D2 → pulse generator provided on the primary side of the step-up transformer A capacitor charging circuit is configured to charge the capacitor C1 to one polarity with the output voltage Ve1 of one half cycle of the generator 12.

The thyristor SCR1, the resistor R1 and the capacitor C2 constitute a discharging switch for discharging the electric charge of the capacitor C1 through the primary coil of the step-up transformer, and the diodes D3 and D4 and the resistors R2 and R2.
3 and a Zener diode ZD1, a discharge switch for providing a trigger signal to a thyristor SCR1 constituting a discharge switch when the output voltage Ve2 of the other half cycle of the generator 12 reaches a set level Vs. A trigger circuit is configured.

The set level Vs is determined by the resistances R2 and R3.
And the Zener voltage V of the Zener diode ZD1
Determined by z. In the present invention, the set level V
s is set lower than the peak value of the output voltage of the generator 12 when no load is applied, and higher than the peak value of the output voltage (rated voltage) of the generator when the rated discharge current is flowing through the discharge lamp 13. ing. That is, in the discharge lamp lighting device of FIG. 2, only when the output voltage (peak value) of the generator 12 is higher than the rated voltage (peak value) of the discharge lamp 13, the resistors R2 and R
The output voltage V1 of the voltage dividing circuit composed of the thyristor SCR exceeds the Zener voltage VZ of the Zener diode ZD1.
The resistance values of the resistors R2 and R3 and the Zener voltage of the Zener diode ZD1 are set so that a trigger signal is given to the resistor R1.

The bypass capacitor 14C is provided to bypass the high-voltage pulse Vp generated by the pulse generation circuit 14 from the generator 12. Therefore, it is preferable to use a film capacitor having good high-frequency characteristics as the bypass capacitor 14C.

In the example shown in FIG. 2, the pulse generation control means 15 comprises a temperature-sensitive resistance element Rt having a negative temperature coefficient, such as a thermistor. The temperature-sensitive resistance element Rt is connected in parallel between the gate and cathode of the thyristor SCR1 (trigger signal input terminal of the discharge switch). In this example, the temperature-sensitive resistance element Rt is the core F of the step-up transformer 14A.
Alternatively, it is thermally coupled to a winding composed of a primary coil W1 and a secondary coil W2 wound around the iron core, and the resistance value of the temperature-sensitive resistance element Rt changes according to the temperature of the step-up transformer 14A to increase the step-up voltage. The temperature of the transformer 14A is detected.

The temperature-sensitive resistance element Rt and the resistance R1 are connected in parallel to the gate-cathode circuit of the thyristor SCR1, and the parallel circuit of the temperature-sensitive resistance element Rt and the resistance R1 is connected to the gate of the thyristor SCR1 through the Zener diode ZD1. A part of the trigger signal current supplied to the thyristor SCR1 is bypassed from the gate cathode circuit of the thyristor SCR1.

In the example shown in FIG. 2, the temperature of the step-up transformer 14A detected by the temperature-sensitive resistance element Rt is equal to the set temperature Ts.
Is exceeded, the resistance value of the temperature-sensitive resistance element Rt becomes smaller than the set value Rts, so that the thyristor SCR1 does not conduct.
Is selected.

The set temperature Ts is the maximum temperature of the step-up transformer 14A which is allowed to keep the temperatures of the step-up transformer 14A constituting the pulse generating circuit 14 and other elements within the allowable temperature range of each element. Is selected to be a value that is close to

Further, the timer power supply circuit 16 is set so that when the output voltage of the generator 12 exceeds the set level Vs, the Zener diode ZD2 becomes conductive and a base current flows through the transistor TR2. Therefore, when the output voltage of the generator 12 exceeds the set level Vs, the transistor TR2 conducts and the capacitor C4 is charged. The voltage across capacitor C4 is at set level V
If the set value is slightly higher than s, the transistor T
R2 is turned off, and charging of the capacitor C4 stops. Therefore, a constant DC voltage Vcc higher than the set level Vs and lower than the no-load output voltage Va of the generator is obtained at both ends of the capacitor C4.

The constant DC voltage output from the timer power supply circuit 16 is applied to the power supply terminal of the timer IC 17A. The timer IC 17A includes a pulse oscillation circuit OSC and a counter that counts output pulses of the oscillation circuit. The counter performs a timed operation by counting the pulses.

The timer power supply circuit 16 to the timer circuit 17
A constant timer driving DC voltage Vcc (FIG.
B), the set terminal (Se) in the timer IC
At t), a voltage is applied as shown in FIG. 4C, and the timer IC is set. Thus, the internal oscillation circuit OSC starts oscillating at a frequency determined by the resistors R7 and R8 and the capacitor C5, and the oscillation circuit OSC generates a pulse as shown in FIG. At the same time, the counter in the timer IC starts counting output pulses of the oscillation circuit OSC (timed operation). While the counter is performing the counting operation, the output voltage Vo obtained at the output terminal OUT of the timer IC is in a state of zero level. When the count value of the counter in the timer IC reaches the set value (timed operation is completed),
The oscillation circuit OSC stops oscillating at the same time as the output voltage Vo of the timer IC becomes high.

When the output voltage Vo of the timer circuit 17 is in the state of zero level, the transistor TR1 is in the cut-off state as shown in FIG. In this state, the trigger signal is allowed to be supplied to the thyristor SCR1. Therefore, when the output voltage of the generator 12 reaches the set level Vs and the Zener diode ZD1 becomes conductive, the thyristor SCR1 is turned on.
A trigger signal is applied to CR1 to make the thyristor conductive.

On the other hand, when the timer circuit 17 completes the timed operation and its output voltage Vo becomes high,
Since the transistor TR1 is turned on, all the trigger signals of the thyristor SCR1 are bypassed from the thyristor SCR1 through the transistor TR1. Therefore, after the timer circuit 17 completes the timed operation, the thyristor S
CR1 cannot conduct.

In the discharge lamp lighting device shown in FIG. 2, when the switch SW is closed while the generator 12 is operating, the generator 12 outputs one half cycle of the output voltage Ve1.
Is generated, the pulse generating capacitor C1 is charged to the polarity shown in the figure through the switch SW, the diode D1, the primary coil W1, and the diode D2. When the discharge lamp 13 is started, the charging voltage of the capacitor C1 is substantially equal to the peak value of the no-load output voltage of the generator 12. When the generator 12 generates the output voltage Ve2 of the other half cycle and the peak value of the output voltage Ve2 exceeds the set level Vs, the resistor R2
And R3, the output voltage V1 of the voltage dividing circuit exceeds the Zener voltage Vz of the Zener diode ZD1, so that the Zener diode conducts. At this time, the timer circuit 17
Is performing a timed operation and its output voltage Vo is at a zero level, so that the transistor TR1 is in a cut-off state, and the thyristor S
CR1 is allowed to receive a trigger signal.

When the Zener diode ZD1 is turned on, the step-up transformer 1 detected by the temperature-sensitive resistance element Rt is used.
If the temperature of 4A does not exceed the set temperature Ts, a trigger current greater than the trigger gate current flows through the thyristor SCR1 and the thyristor conducts, and the capacitor C1
Discharges through the thyristor SCR1 and the primary coil W1. When a pulsed primary current flows through the primary coil W1 of the step-up transformer due to the discharge of the capacitor C1, a boosted high voltage pulse Vp is induced in the secondary coil W2 of the step-up transformer. The high voltage pulse Vp is superimposed on the output voltage Ve2 of the other half cycle of the generator 12 and applied to the discharge lamp 13.

The peak value of the high voltage pulse Vp induced in the secondary coil W2 of the step-up transformer is determined by the capacitance of the pulse generating capacitor C1, the magnitude of the charging voltage of the capacitor C1, the turn ratio of the step-up transformer 14A, It is almost determined by the capacitance of the transformer.

The generator 12 used in the present invention is configured so that the output voltage-output current characteristic exhibits a drooping characteristic. When the discharge lamp is started, the voltage applied to the discharge lamp 13 starts discharging. Generator 12 so that it is higher than the voltage.
The output voltage at no load is set. In addition, the short-circuit current of the generator 12 has a magnitude necessary to limit the discharge current (in a cold state) immediately after the discharge lamp 13 starts to be discharged to a value equal to or less than an allowable value. The output voltage versus output current characteristics of the generator 12 are set so that the discharge current is kept within the rated range.

An example of the output voltage V vs. output current i characteristic of the generator 12 used in the present invention is as shown by a curve A in FIG. 3, for example. FIG. 3 shows an example of the voltage-current characteristics of a high-pressure discharge lamp such as a metal halide lamp when it is cold. As illustrated, the discharge lamp 13 has a negative impedance characteristic in which the terminal voltage decreases as the discharge current increases.

The voltage VA at the point A in the curve B in FIG. 3 is the discharge starting voltage. In order to light the discharge lamp, it is necessary to apply a voltage higher than the voltage VA at the point A to both ends of the discharge lamp. . In the present invention, the no-load output voltage Va of the generator and the capacitor C1 are set so that the voltage applied to the discharge lamp when the high voltage pulse is generated at the start of the discharge lamp becomes higher than the discharge starting voltage VA. Capacitance and step-up transformer 1
Since the step-up ratio of 4 A is set, when the switch SW is closed and the pulse generation circuit 14 generates the high voltage pulse Vp, the discharge lamp 13 starts discharging.

When the discharge lamp 13 starts discharging, the impedance of the discharge lamp rapidly decreases as shown by the curve (b) in FIG. It increases to point B where it intersects. The discharge current at the point B is the discharge current in the cold state immediately after the start of the discharge. The discharge current immediately after the start of discharge shows a larger value as the short-circuit current ic of the generator is larger. In the present invention,
The output voltage vs. output current characteristic of the generator is defined as a drooping characteristic, and the magnitude of the short-circuit current (current at point c in FIG. 3) ic of the generator 12 is set so that the discharge current flowing immediately after the start of discharge is limited to an allowable value or less. The discharge lamp 1
The discharge current flowing through 3 does not exceed the allowable value.

When the temperature of the discharge lamp 13 increases, the internal impedance of the discharge lamp increases, so that the discharge current decreases, and the discharge lamp is in a thermally stable state (steady state).
Becomes stable at the intersection of the voltage-current characteristic curve C of the discharge lamp at that time and the output voltage-output current characteristic curve B of the generator 12. In the present invention, in the steady state (when the discharge lamp is in a thermally stable state), the voltage VL and the discharge current iL at both ends of the discharge lamp (for example, the voltage / current at point b in FIG. 3) are within the rated range of the discharge lamp. The output voltage vs. output current characteristics of the generator are set to be within the range. Therefore, in a steady state of the discharge lamp, a discharge current in a substantially rated range flows, and a voltage at both ends thereof is substantially equal to the rated voltage.

That is, in the present invention, in the example of FIG. 3, the characteristics of the generator are set so that the output voltage-output current characteristic curve A passes through the points a, b and c. . If the characteristics of the generator are set in this way, the discharge of the discharge lamp can be started without using a ballast, and the discharge current immediately after the discharge can be limited to an allowable value or less. An operating point can be secured.

As in the above example, only when the output voltage of the generator 12 is higher than the rated voltage VL of the discharge lamp 13, the output voltage V1 of the voltage dividing circuit composed of the resistors R2 and R3 becomes the Zener diode ZD1. In order to provide a trigger signal to the thyristor SCR1 beyond the voltage Vz, the resistor R2
If the resistance of R3 and the Zener voltage of the Zener diode ZD1 are selected, when the discharge lamp 13 is normal, a high-voltage pulse is generated only when the discharge lamp 13 is started, and the discharge lamp starts discharging. When the output voltage of the generator falls below the rated value, the high-voltage pulse disappears. Therefore, it is possible to prevent an unnecessary high voltage pulse from being generated after the discharge lamp is turned on and adversely affecting the discharge lamp, and to prevent the output of the generator from being unnecessarily consumed.

The drooping characteristic as shown by the curve A in FIG.
The number of turns of the armature winding of the generator 12 is appropriately set, or the rotor and the stator are arranged so as to increase the leakage magnetic flux flowing through the adjacent magnetic pole when the magnetic pole of the rotor faces the magnetic pole of the stator. It can be easily obtained by adjusting the pole arc angle of the magnetic pole. In particular, when a magnet-type AC generator is used as the generator 12, it is possible to easily obtain the drooping characteristics passing through the points a, b, and c by adjusting the number of turns of the armature winding and the pole arc angle of the stator magnetic pole. Can be.

The generator 12 used in the present invention only needs to have an output voltage-output current characteristic A at which points a, b and c shown in FIG. 3 can be obtained. It is not limited to. For example, an inductor rotating type having a magnet and an armature coil on the stator side, having an inductor on the rotor side, and inducing an AC voltage in the armature coil by a magnetic flux and a change generated by rotation of the inductor. A magnet-type AC generator, a synchronous generator, a DC generator, or the like can be used.

FIG. 5B shows the change in the output voltage Ve (peak value) of the generator 12 when the discharge lamp is normally lit in the discharge lamp lighting device shown in FIG. Before the discharge lamp is turned on, the output voltage Ve of the generator holds the value Va at no load. When the switch SW is turned on at time t1, the pulse generation circuit 14
Generates a high-voltage pulse, so that the discharge lamp 13 is turned on. When the discharge lamp is turned on, its internal impedance decreases, and the output voltage of the generator rapidly decreases.

When the temperature rises after the discharge lamp is turned on, the internal impedance gradually increases, so that the discharge current gradually decreases, and the output voltage Ve of the generator 12 gradually increases. To rise. When the discharge lamp is in a thermally stable state (steady state), the discharge lamp is stabilized at the intersection of the discharge lamp impedance curve at that time and the output voltage versus output current characteristic curve of the generator, and the output voltage Ve of the generator 12 becomes the rated value Vb. Calm down.

When the switch SW is opened at time t2, the discharge lamp 13 is turned off, and the output voltage Ve of the generator rises to the no-load voltage Va.

Thereafter, at time t3 when the temperature of the discharge lamp is still high, when the switch SW is turned on again,
The timer circuit 17 starts timed operation and the pulse generation circuit 1
4 permits the generation of a high-voltage pulse, and the pulse generation circuit 14 starts generating a high-voltage pulse. However, when the temperature of the discharge lamp is high, the discharge can be started even when the high-voltage pulse is applied. I can do it. After the switch SW is closed at time t3 and the predetermined cooling time Tc elapses and the temperature of the discharge lamp 13 decreases, the discharge lamp 13 is turned on again, and the output voltage Ve of the generator decreases.

As described above, when the discharge lamp is to be lit again during heating, after the switch is turned on, a predetermined cooling time T
It is necessary to continue the generation of the high voltage pulse until elapses, and it is necessary that the timer circuit 17 continue the timed operation until the cooling time Tc elapses. Therefore, it is preferable that the operation time limit of the timer circuit 17 is set to a minimum length necessary for re-lighting the discharge lamp 13 when hot.

In the discharge lamp lighting device of FIG.
When it takes time before the discharge lamp is turned on due to deterioration of the discharge lamp 3, the pulse generating circuit 14 continues to generate a high voltage pulse, and the primary coil W1 of the step-up transformer 14A through which the discharge current of the pulse generating capacitor C1 flows. And the heat of the thyristor SCR1 continues, and the temperature of the step-up transformer 14A and the thyristor SCR1 may exceed the allowable temperature.

Therefore, in the lighting device shown in FIG. 2, the temperature of the element which generates heat with the generation of the high voltage pulse is detected,
The generation of the high voltage pulse is stopped when the detected temperature exceeds the set temperature.

In the example shown in FIG. 2, the step-up transformer 14A
When the temperature of the step-up transformer detected by the temperature-sensitive resistance element Rt thermally coupled to the temperature sensor exceeds the set temperature Ts, the resistance value of the temperature-sensitive resistance element Rt becomes smaller than the set value Rts, and is connected to the gate of the thyristor SCR1. The supplied gate current is smaller than the trigger gate current of the thyristor. Therefore, the thyristor SCR1 is turned off, and the pulse generation circuit 14 stops generating the high voltage pulse Vp. When the generation of the high voltage pulse stops, the heat generation of the step-up transformer 14A and the thyristor SCR1 stops, and the respective temperatures decrease. When the temperature of the step-up transformer 14A detected by the temperature-sensitive resistance element Rt becomes lower than the set temperature Ts, the pulse generation circuit 14 again generates the high voltage pulse Vp. The same operation is repeated until the discharge lamp 13 is turned on, and the pulse generation circuit operates intermittently to prevent dielectric breakdown and burning due to overheating of the elements constituting the pulse generation circuit.

Next, in the lighting device of FIG.
It is assumed that the lit discharge lamp 3 is turned off (opened) due to its life or accident. At this time, the generator 12 generates the no-load voltage Va higher than the set level Vs as shown in FIG. 5A, so that the Zener diode ZD1 of the pulse generation circuit 14 becomes conductive. Further, since the timer circuit 17 starts the timed operation, the output voltage Vo of the timer circuit 17 becomes zero level, and the supply of the trigger signal to the thyristor SCR1 is permitted. Therefore, each time the output voltage of the generator reaches the set level Vs, the thyristor SCR1 conducts and a high voltage pulse is generated.

When the timer circuit 17 completes the timed operation,
Since the output voltage Vo becomes high level, the transistor TR1 conducts and the supply of the trigger signal to the thyristor SCR1 is blocked. Thereby, the pulse generation circuit 14 stops generating the high voltage pulse.

As described above, in the discharge lamp lighting device according to the present invention, when the discharge lamp is turned off, the generation of the high voltage pulse is stopped when the timer circuit 17 completes the timed operation. In addition, it is possible to prevent a problem that the generation of the high voltage pulse continues for a long time and the insulation life of the circuit element is shortened.

The pulse generating circuit 14 used in the lighting device according to the present invention may be any circuit that generates a high-voltage pulse using the generator 12 as a power supply, and the configuration is not limited to the above example.

In the pulse generation circuit 14 shown in FIG. 2, a temperature-sensitive resistance element Rt connected in parallel between the gate and cathode of a thyristor SCR1 as a discharge switch is thermally coupled to a step-up transformer 14A. Although it is configured to detect the temperature of the step-up transformer, the temperature-sensitive resistance element Rt having a negative temperature coefficient generates heat in accordance with generation of a high-voltage pulse in the elements constituting the pulse generation circuit 14. Element, for example, thyristor SC as discharge switch
It may be thermally coupled to R1. In this case, the thyristor SC detected by the temperature-sensitive resistance element Rt
The generation of the high-voltage pulse is stopped when the temperature of R1 exceeds the set temperature, and the set temperature Ts is the temperature of the thyristor SCR1 constituting the pulse generating circuit 14 and the temperatures of the other heating elements, respectively. Thyristor SCR allowed to fall within the allowable temperature range of the device
The value is selected to be close to the maximum temperature of 1.

[0089]

As described above, according to the present invention, when the discharge lamp that has been lit due to the life of the discharge lamp or an accident or the like is turned off, the timer circuit performs a timed operation.
Since the generation of the high-voltage pulse is stopped when the timed operation is completed, when the discharge lamp is turned off, the high-voltage pulse remains generated for a long time, and the circuit element The life can be prevented from being shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a discharge lamp lighting device according to the present invention.

FIG. 2 is a circuit diagram showing an example in which each part of the lighting device shown in FIG. 1 is concretely illustrated;

FIG. 3 is a diagram showing an output voltage-output current characteristic of a generator used in the present invention and a voltage-current characteristic of a discharge lamp.

FIG. 4 is a diagram for explaining the operation of the timer circuit used in the present invention.

FIGS. 5A and 5B show changes in the output voltage (peak value) of the generator used in the present invention, wherein FIG. 5A is a diagram showing the output voltage of the generator when there is no load, and FIG. 5B is a discharge lamp. FIG. 5 is a diagram showing a change in output voltage of the generator when is turned on.

FIG. 6 is a configuration diagram showing a previously proposed discharge lamp lighting device.

[Explanation of symbols]

11 internal combustion engine, 12 generator, 13 discharge lamp, 14
Pulse generating circuit, 14A: step-up transformer, 14B: primary current control circuit, 16: timer power supply circuit, 17: timer circuit.

Claims (3)

[Claims] 1. An internal combustion engine, a generator driven by the internal combustion engine to output a voltage for driving a discharge lamp, and a pulse generation circuit for generating a high voltage pulse for starting the discharge lamp using the generator as a power source. The output of the generator and the output of the pulse generation circuit are superimposed and applied to a discharge lamp, and the pulse generation circuit is configured to output the generator when a rated discharge current is flowing through the discharge lamp. The generator is configured to generate the high-voltage pulse when the generator outputs a voltage equal to or higher than a set level set higher than the output voltage value of the generator, and the generator has a drooping output voltage-output current characteristic. The short-circuit current of the generator is set so as to exhibit a characteristic, and the discharge current immediately after the start of the discharge of the discharge lamp is set to a value equal to or less than an allowable value. And release In the internal combustion engine drive discharge lamp lighting device in which the output voltage versus output current characteristic of the generator is set so as to keep the current within the rated range, the timed operation is performed when the pulse generation circuit is in a state of generating a high voltage pulse. A timer circuit that starts generating the high voltage pulse while the timer circuit is performing the timed operation, and prohibits the generation of the high voltage pulse when the timer circuit completes the timed operation. An internal combustion engine drive discharge lamp lighting device, comprising: pulse generation circuit control means for controlling a pulse generation circuit. 2. An internal combustion engine, a generator driven by the internal combustion engine, and a pulse generation circuit for generating a high voltage pulse using the generator as a power source, wherein the pulse generation circuit includes a step-up transformer, A pulse generating capacitor provided on the primary side of the step-up transformer,
A capacitor charging circuit for charging the pulse generating capacitor to one polarity by an output voltage of the generator; and a capacitor charging circuit for discharging the charge of the pulse generating capacitor through a primary coil of the step-up transformer when the capacitor is turned on. The discharge switch and the output voltage of the generator are set lower than the output voltage of the generator when no load is applied, and higher than the output voltage of the generator when the rated discharge current is flowing through the discharge lamp. A discharge switch trigger circuit that provides a trigger signal to a trigger signal input terminal of the discharge switch when the discharge switch reaches a set level, thereby turning on the discharge switch. When the discharge lamp is started, a high-voltage pulse having a magnitude necessary to make the voltage applied to the discharge lamp equal to or higher than the discharge starting voltage is applied to the booster. The output voltage of the generator is applied to the discharge lamp through the secondary coil of the step-up transformer, and the generator has a drooping characteristic with respect to an output voltage-output current characteristic. It is configured to exhibit, the short-circuit current of the generator is set so as to limit the discharge current immediately after the start of the discharge of the discharge lamp to an allowable value or less, terminal voltage of the discharge lamp in a steady state and In the internal combustion engine drive discharge lamp lighting device in which the output voltage-output current characteristic is set so as to keep the discharge current within a rated range, the timer drive is performed when the generator outputs a voltage exceeding the set level. A timer power supply circuit for outputting a DC voltage; and a trigger provided to bypass a trigger signal of a discharge switch of the pulse generation circuit when the switch is turned on. A signal bypass switch, to start a timed operation when the timer power supply circuit outputs a constant DC voltage, and to hold the trigger signal bypass switch in an interrupted state while performing the timed operation; And a timer circuit for controlling the trigger signal side switch so that the trigger signal side switch is turned on when the timed operation is completed. 3. The internal combustion engine according to claim 1, wherein an operation time limit of the timer circuit is set to a minimum length required to relight the discharge lamp when hot. Drive discharge lamp lighting device.