JP3505937B2 - Inverter device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter device for converting the output of a chopper circuit into a high frequency, which is used, for example, in a discharge lamp lighting device.

[0002]

2. Description of the Related Art FIG. 20 shows a conventional discharge lamp lighting device.
This discharge lamp lighting device applies the output of the inverter circuit 1 for converting a DC voltage to a high frequency voltage to the discharge lamp L to light the discharge lamp L at a high frequency. The DC voltage is generated by rectifying the AC power supply AC by the rectifier circuit 2 including a diode bridge and boosting the rectified output by the booster chopper circuit 3. The chopper circuit 3 includes a switching element Q1, a choke coil L1, and a diode D.
1. The control circuit 4 switches the switching element Q1 at a high frequency to chop the output of the rectifier circuit 2 and accumulates in the choke coil L1 when the switching element Q1 is on. This energy is released through the diode D1 when the switching element Q1 is off, and the chopping voltage output through the diode D1 is smoothed by the capacitor C3. An active filter control IC is mainly used for the control circuit 4.

In this discharge lamp lighting device, a separately excited half bridge structure is used as the inverter circuit 1. The inverter circuit 1 alternately turns on / off the main switching elements Q2, Q3 connected in series to the output of the chopper circuit 3, a drive circuit 5 for driving these main switching elements Q2, Q3, and the main switching elements Q2, Q3. It is composed of a control circuit 6 for doing so. The main switching elements Q2 and Q3 include the main switching elements Q2 and
Free-wheeling diodes D2 and D3 are connected in antiparallel to both ends of Q3. A resonance circuit 7 including a choke coil L2 and a capacitor C2 is connected to the output of the inverter circuit 1, and the resonance circuit 7 is excited by the inverter circuit 1 to start and light the discharge lamp L.

Further, the capacitor C1 is a capacitor for cutting direct current, and the charge charged when the main switching element Q2 is turned on is used as a power source when the transistor Q3 is turned on. The control circuit 6 alternately turns on and off the main switching elements Q2 and Q3,
When the inverter circuit 1 is oscillated, a high voltage is applied across the discharge lamp L by the resonance circuit 7, and the discharge lamp L is lit. After that, the control circuit 6 performs on / off control of the main switching elements Q2 and Q3 in a predetermined cycle to maintain the lighting of the discharge lamp L. With such a configuration, the input power factor becomes almost 1, and the distortion factor of the input current becomes small, so that it is possible to provide an inverter device having less harmonic components.

However, in this circuit, separate control circuits are required for the chopper circuit 3 and the inverter circuit 1, and there is a problem that the control circuit becomes complicated and the cost increases due to an increase in the number of parts.

FIG. 21 is a circuit diagram showing still another conventional example. In this circuit, one of the main switching elements Q3 in the inverter circuit 1 also serves as the switching element Q1 of the chopper circuit 3 in FIG. The switching elements Q2 and Q3 are alternately turned on and off to supply high-frequency power to the discharge lamp L, but the switching element Q3 also functions as a switching element of the chopper circuit 3. That is, first, when the switching element Q3 is turned on, the DC output end of the rectifier circuit 2 is connected to the choke coil L1.
, And energy is stored in the choke coil L1. Next, when the switching element Q3 is turned off,
Energy of the choke coil L1 is released to the capacitor C3 via the diode D2. That is, the switching element Q3 also functions as the switching element Q1 of FIG. 20, and the diode D2 is the diode D1 of FIG.
Of the switching element Q.
Since 1 and the diode D1 can be omitted, there is an advantage that the number of used elements is reduced. Further, the control circuit 4 for the switching element Q1 is also unnecessary.

However, in this circuit, since the chopper current and the inverter current simultaneously flow only in the switching element Q3 and the diode D2 which are shared by the chopper circuit 3 and the inverter circuit 1, one switching in the inverter circuit 1 is performed. There is a problem that stress concentrates only on the element Q3. Further, since the switching element Q3 is shared by the chopper circuit 3 and the inverter circuit 1, it is difficult to control the chopper circuit and the inverter circuit independently. For example, at the time of starting the lighting of the discharge lamp or the dimming lighting control of the discharge lamp. When the load is off when multiple discharge lamps are lit in parallel, or when there is a load change such as at the end of the discharge lamp life,
A separate control circuit is required to control the output of the chopper circuit, and there are problems that the control circuit becomes complicated and the cost increases due to an increase in the number of parts.

[0008]

As described above, as described above,
Various inverter devices have been proposed, but in order to improve the input power factor and reduce the input current distortion factor, it is necessary to provide a chopper circuit between the AC power supply and the inverter circuit.
Since it is necessary to provide separate control circuits for the chopper circuit and the inverter circuit, there is a problem that the control circuit is complicated and the cost is increased due to an increase in the number of parts.

Further, in the system in which the switching elements of the chopper circuit and the inverter circuit are shared, there is a problem that stress concentrates on only one switching element of the inverter circuit, and the switching elements of the chopper circuit and the inverter circuit are combined. Since it is shared, it is difficult to control the chopper circuit and the inverter circuit independently.For example, when starting the lighting of the discharge lamp, when controlling the dimming lighting of the discharge lamp, when the load is off during parallel lighting of multiple discharge lamps, When the load fluctuates at the end of life or the like, a separate control circuit is required to control the output of the chopper circuit, which causes a problem that the control circuit becomes complicated and the cost increases due to an increase in the number of parts.

The present invention has been made in view of the above points, and an object of the present invention is to solve the above-mentioned drawbacks of the conventional example, to use a small number of elements, and to control easily, An object of the present invention is to provide an inverter device that can achieve an input power factor and a low input current distortion factor.

[0011]

In order to solve the above-mentioned problems, the inverter device of the present invention switches the output voltage of the rectifier circuit 2 connected to the AC power supply AC as shown in FIG. A step-up chopper circuit 3 that chops the element Q1 by turning it on and off, converts the chopping voltage to a predetermined DC voltage V _DC by rectifying and smoothing it, and suppresses input current waveform distortion, and an output of the step-up chopper circuit 3. Switching element Q connected in series
The booster chopper circuit 3 and the inverter circuit 1 are provided with an inverter circuit 1 that alternately turns on and off Q2 and Q3 to supply high frequency power to the load L via the LC resonance circuit 7.
As a means for interlocking control of the drive signals Ve and Vb of the respective switching elements of FIG.
One with variable oscillation frequency according to the load condition of path 1
Of the oscillation circuit 9 and the oscillation output of this oscillation circuit 9.
Drive the switching element of the inverter circuit 1
First monostable multivibrator 11 for generating a signal
And triggered by the oscillation output of the oscillation circuit 9 to rise.
The drive signal of the switching element of the pressure chopper circuit 3
A second monostable multivibrator 10 for generating;
The pulse width of the monostable multivibrator 10 of
A means for changing the output voltage of the chopper circuit 3
It is characterized by being provided .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A basic embodiment of the present invention is shown in FIGS. Here, the inverter circuit 1 and the chopper
-A description will be given of the configuration in which the oscillation circuit 9 common to the circuit 3 is used.
Reveal FIG. 1 shows the configuration of the main circuit of the discharge lamp lighting device, and FIG. 2 shows the configuration of its control circuit. In the conventional example shown in FIG. 20, the control circuits 4 and 6 are replaced by a control circuit 8. Has become. The control circuit 8 uses the trigger signal V
an oscillation circuit 9 for oscillating a at an arbitrary frequency, and a monostable multivibrator IC 10 (for example, μP) that receives the trigger signal Va and outputs a pulse signal Ve for driving the switching element Q1 of the chopper circuit 3.
D4538) and the monostable multivibrator IC 11 which receives the trigger signal Va and outputs a pulse signal Vb for driving the switching elements Q2 and Q3 of the inverter circuit 1. The DC power source E of the control circuit 8 is obtained by rectifying and smoothing the AC power source AC (or its full-wave rectified output V _DB ) with a rectifying / smoothing circuit 12 including a diode D4, a resistor R1, a capacitor C4 and a constant voltage diode ZD1. ing.

The operation of the control circuit 8 of the present invention will be described below with reference to FIG. FIG. 3 shows the waveform of each part in the circuit configuration shown in FIG. Oscillator circuit 9
The trigger signal Va output from is output at the timing shown in FIG. When the trigger signal Va rises to the high level, the output Vb of the monostable multivibrator IC11 is at the high level and the output Vc becomes the low level. Similarly, when the trigger signal Va rises to the high level, the output of the monostable multivibrator IC10. Vd is at high level and output Ve is at low level. The output Vb of the monostable multivibrator IC11 has a period T determined by the time constant of the resistor R2 and the capacitor C5 shown in FIG.
Only 1 goes to high level, monostable multivibrator I
The output Vd of C10 is the resistance R3 and the capacitor C shown in FIG.
It goes high for a period T2 determined by the time constant of 6. 3 (b) to 3 (e) are monostable multivibrator ICs, respectively.
11 output Vb, monostable multivibrator IC 11 output Vc, monostable multivibrator IC 10 output Vc
d, the output waveform of the output Ve of the monostable multivibrator IC 10 is shown.

The output Vb of the monostable multivibrator IC 11 is connected to the drive circuit 5 of the inverter circuit 1, and the drive circuit 5 alternately turns on / off the main switching elements Q2 and Q3 according to the signal of the output Vb of the monostable multivibrator IC 11. Let In this example, when the output Vb of the monostable multivibrator IC11 is at a high level, the switching element Q2 is turned off and the switching element Q3 is turned on, and the output Vb of the monostable multivibrator IC11 is turned on.
When b is at a low level, the switching element Q2 is turned on and the switching element Q3 is turned off. Further, in this example, the monostable multivibrator IC1
The on-duty of the signal of the output Vb of 1 is about 50%. FIG. 3 (g) shows the current I _Q3 flowing through the switching element Q3.

Next, the monostable multivibrator IC 10
Output Ve is the switching element Q of the chopper circuit 3.
When the output Ve of the monostable multivibrator IC 10 is at a high level, the switching element Q1 is turned on and the output V of the monostable multivibrator IC 10 is turned on.
When e is at a low level, the switching element Q1 is turned off. FIG. 3 (h) shows the current I _Q1 flowing through the switching element Q1.

As described above, in the control circuit 8 of FIG. 2, since the timing of the switching operation of the main switching element of the inverter circuit 1 and the switching element of the chopper circuit 3 is given by the common oscillating circuit 9, the used element is used. The number is small and the configuration of the control circuit 8 can be simplified.

[0017]

FIG. 4 is a circuit diagram of a main circuit according to a first embodiment of the present invention. In the discharge lamp lighting device of the present embodiment, the choke coil L2 and the capacitor C are provided at the output of the inverter circuit 1.
2 resonance circuits 7 are connected in parallel,
The discharge lamp L of the lamp is configured to be lit at high frequency. In the present invention, the number of discharge lamps L does not matter.

FIG. 5 is a circuit diagram of the control circuit 8 according to the first embodiment of the present invention. The control circuit 8 of this embodiment is a timer IC.
22 (for example, μPC1555), an oscillator circuit 9 including a capacitor C7 and a resistor R4, and a chopper circuit 3
A monostable multivibrator IC 10 for outputting a pulse signal Ve for driving the switching element Q1 of
A monostable multivibrator IC 11 that outputs a pulse signal Vb for driving the switching elements Q2 and Q3 of the inverter circuit 1, and an oscillation frequency switching unit that varies the oscillation frequency of the trigger signal Va output from the oscillation circuit 9. 13 and the oscillation frequency of the power switch SW1
The timer circuit 14 for fixing the preheating start frequency and the DC voltage VC3 output from the chopper circuit 3 for a certain period from the time when the lamp is turned on to the time when the discharge lamp L is turned on and the DC voltage VC3 output from the chopper circuit 3.
7, and a chopper output controller 15 for variably controlling the high level period of the pulse signal Ve for driving the switching element Q1 of the chopper circuit 3 according to the DC voltage. There is. Also,
The oscillation frequency switching unit 13 includes a switch SW2, a diode D5, resistors R5 and R6, and a capacitor C8.
And a dimming signal circuit 16 including a transistor Q4 are connected.

The trigger signal Va output from the oscillation circuit 9
The oscillation frequency is determined by the charging / discharging time of the capacitor C7, and the capacitor C7 is connected to the transistor Q5 of the oscillation frequency switching unit 13. The transistor Q5 has
Transistor Q to form a current mirror circuit
6 is connected and the current flowing in the transistor Q5 is the resistance R9, R10, R1 connected to the transistor Q6.
It is determined by the resistance circuit configuration of 1.

The timer circuit 14 sets the preheating time, and the reference voltage, which is the divided voltage by R12 and R13, is applied to the inverting input terminal of the comparator CP1 provided in the timer circuit 14, so that the comparator CP1 is not supplied with the reference voltage. The voltage of the capacitor C9 is applied to the inverting input terminal. When the switch SW1 (FIG. 4) is turned on and the DC power source E is generated in the capacitor C4 of the rectifying / smoothing circuit 12, the charging voltage of the capacitor C9 of the timer circuit 14 rises, and the output terminal of the comparator CP1 charges the capacitor C9. It is low level when the voltage is lower than the reference voltage, and high level when the voltage is higher than the reference voltage. The output terminal of the comparator CP1 is connected to the resistor R9 of the oscillation frequency switching unit 13. Therefore, the transistor Q6 of the oscillation frequency switching unit 13 has
Since the parallel circuit of the resistors R9 and R10 is connected, the current flowing through the transistor Q5 is also determined, the charging / discharging time of the capacitor C7 of the oscillation circuit 9 is determined, and the oscillation frequency of the output trigger signal Va is The frequency is fixed at the time of preheating. When the output terminal of the comparator CP1 of the timer circuit 14 becomes high level, the resistor R9 of the oscillation frequency switching unit 13 forms a series circuit with the capacitor C10, so that the current flowing through the transistor Q6 decreases as the capacitor C10 is charged, Finally, the resistor R10 is connected in series to the transistor Q6,
This also determines the current flowing through the transistor Q5,
The charging / discharging time of the capacitor C7 of the oscillation circuit 9 is determined,
The oscillation frequency of the output trigger signal Va is fixed to the frequency during lighting.

Further, the resistor R11 of the oscillation frequency switching unit 13
Is connected to the transistor Q4 of the dimming signal circuit 16, and when the transistor Q4 is turned on by operating the switch SW2 of the dimming signal circuit 16, the oscillation frequency switching unit 13
The parallel circuit of the resistors R10 and R11 is connected to the transistor Q6 of the above, whereby the current flowing through the transistor Q5 is also determined, and the charge / discharge time of the capacitor C7 of the oscillation circuit 9 is determined and output. The oscillation frequency of the trigger signal Va is fixed to the frequency during dimming.

Switching element Q1 of chopper circuit 3
Monostable multivibrator IC 10 for driving
The ON period of the pulse signal Ve output from is determined by the time constant of the resistor R3 and the capacitor C6. Further, the time constant setting terminal T2 of the monostable multivibrator IC 10 has a chopper output control unit 15 including a current mirror circuit including transistors Q7 and Q8 and resistors R15 and R16.
Are connected. The transistor Q8 has a resistor R7 for detecting the output DC voltage V _DC of the chopper circuit 3,
Since R8 is connected, the current flowing through the transistor Q7 changes according to the output DC voltage of the chopper circuit 3. Therefore, the charging current flowing through the capacitor C6 that determines the ON section of the pulse signal Ve also changes, and the ON section of the pulse signal Ve changes according to the output DC voltage of the chopper circuit 3. In the circuit configuration of this embodiment, if the output DC voltage of the chopper circuit 3 tends to increase, the ON period of the pulse signal Ve becomes narrower, and if the output DC voltage of the chopper circuit 3 tends to decrease. , The ON period of the pulse signal Ve is widened.

The operation of this embodiment will be described below with reference to FIG. FIG. 4 shows waveforms at various parts in the circuit configuration of this embodiment. The trigger signal Va output from the oscillator circuit 9 is output at the timing shown in FIG. The frequency of the trigger signal Va is preheat, lighting,
It changes according to each mode of dimming. When the trigger signal Va rises to a high level, the monostable multivibrator I
The output Vb of C11 is high level, the output Vc is low level, and similarly, when the trigger signal Va rises to high level, the output Vd of the monostable multivibrator IC 10 is high level and the output Ve is low level. .
The output Vb of the monostable multivibrator IC11
Becomes high level for a period T1 determined by the time constant of the resistor R2 and the capacitor C5 shown in FIG. FIG. 6B shows the output Vb of the monostable multivibrator IC 11, FIG. 6C.
Shows the waveform of the output Vc of the monostable multivibrator IC11. The output Vb of the monostable multivibrator IC 11 is connected to the drive circuit 5 of the inverter circuit 1,
The drive circuit 5 alternately turns on and off the main switching elements Q2 and Q3 according to the output Vb of the monostable multivibrator IC11. In the present embodiment, when the output Vb of the monostable multivibrator IC11 is high level, the switching element Q2 is turned off and the switching element Q3 is turned on, and the output Vb of the monostable multivibrator IC11 is turned on.
The switching element Q2 is turned on when b is at a low level,
The switching element Q3 is turned off.
FIG. 6 (g) shows the current _IQ3 flowing through the switching element Q3.

The output Vd of the monostable multivibrator IC 10 is output from the period T3 to T4 in accordance with the output DC voltage of the chopper circuit 3 by the time constant of the resistor R3 and the capacitor C6 shown in FIG. 5 and the chopper output controller 15. High level changes at intervals. Therefore, the output Ve of the monostable multivibrator IC 10 similarly changes its low level at intervals of the periods T3 to T4. 6D and 6E show waveforms of the output Vd of the monostable multivibrator IC 10 and the output Ve of the monostable multivibrator IC 10, respectively.

The output Ve of the monostable multivibrator IC 10 is connected to the switching element Q1 of the chopper circuit 3 and is output Ve of the monostable multivibrator IC 10.
Is high, the switching element Q1 is turned on, and when the output Ve of the monostable multivibrator IC 10 is low, the switching element Q1 is turned off.

The output Ve of the monostable multivibrator IC 10 has a high level during the period T5 when the output DC voltage of the chopper circuit 3 tends to increase, and a high level during the period T6 when the output DC voltage tends to decrease. Therefore, the current IQ1 flowing through the switching element Q1 shown in FIG. 6 (h) changes accordingly from the period T5 to the period T5.
The amount of current changes between 6 and 6. That is, the chopper circuit 3
When the output DC voltage is a tendency to increase, decreasing the current I _Q1 flowing through the switching element Q1, the output DC voltage of the chopper circuit 3 is a tendency to decrease, increasing the current I _Q1 flowing through the switching element Q1 Works like. Therefore, the choke coil L1 of the chopper circuit 3
The amount of energy stored in the chopper circuit 3 changes.
The output DC voltage is repeatedly increased and decreased, and is controlled to maintain a substantially constant voltage value.

As described above, in this embodiment, since the common oscillation circuit 9 gives the timing of the switching operation of the main switching element of the inverter circuit 1 and the switching element of the chopper circuit 3, the number of used elements is small, The configuration of the control circuit 8 can be simplified and the chopper circuit 3
Since independent control of the inverter circuit 1 and the inverter circuit 1 can be easily performed, for example, at the start of lighting of the discharge lamp, at the time of dimming lighting control of the discharge lamp, at the time of load off during multiple lighting of the discharge lamp in parallel, at the end of the life of the discharge lamp. It is possible to control the DC output voltage of the chopper circuit 3 so as to be substantially constant with a simple circuit configuration when the load fluctuates during a state or the like.

FIG. 7 is a circuit diagram of the control circuit 8 according to the second embodiment of the present invention. The configuration of the main circuit is the same as in FIG. The circuit configuration of FIG. 7 is almost the same as the circuit configuration of FIG. 5 of the above-described first embodiment, but the monostable multivibrator IC 10 is used.
Output Ve and the output Vb of the monostable multivibrator IC11 are connected via a diode D6.

The operation of this embodiment will be described below with reference to FIG. FIG. 8 shows the waveform of each part in the circuit configuration of this embodiment. 8A to 8E respectively show a trigger signal Va output from the oscillator circuit 9, an output Vb of the monostable multivibrator IC 11, an output Vc of the monostable multivibrator IC 11, an output Vd of the monostable multivibrator IC 10, and a monostable multivibrator IC 10. Stable multivibrator IC1
The output waveform of the output Ve of 0 is shown, and each operation waveform is the same as that shown in FIG. 6 of the first embodiment.

FIG. 8 (f) shows the drive signal V _BE given to the switching element Q1 of the chopper circuit 3. The drive signal V _BE of the switching element Q1 is given from the output Ve of the monostable multivibrator IC10, but the output Ve of the monostable multivibrator IC10 and the output Vb of the monostable multivibrator IC11 are connected via a diode D6. Therefore, the drive signal V _BE is output at the high level only when the output Ve of the monostable multivibrator IC 10 is at the high level and the output Vb of the monostable multivibrator IC 11 is at the high level. Therefore, the drive signal V _BE becomes high level only during the period T7 as shown in FIG. That is, the ON period of the switching element Q1 of the chopper circuit 3 is controlled to be equal to or less than the ON period of one of the switching elements Q2 and Q3 (the switching element Q2 in this embodiment) of the inverter circuit 1. Along with this, the current I _Q1 flowing through the switching element Q1 that shown in FIG. 8 (h), the amount of current varies between periods T5 period T7. The switching element Q is shown in FIG.
3 shows a current I _Q3 flowing through the device ₃ .

As described above, in this embodiment, since the timing of the switching operation of the main switching element of the inverter circuit and the switching operation of the switching element of the chopper circuit are given by the common oscillation circuit, the number of used elements is small and the control circuit Since the configuration can be simplified and independent control of the chopper circuit and the inverter circuit can be easily performed, for example, at the time of starting lighting of the discharge lamp, at the time of dimming lighting control of the discharge lamp, at the time of parallel lighting of multiple discharge lamps. It is possible to control the DC output voltage of the chopper circuit to be almost constant with a simple circuit configuration when the load changes, such as when the load changes or when the discharge lamp has reached the end of its life. Since the ON period of the switching element is less than the ON period of either of the switching elements of the inverter circuit, the output voltage of the chopper circuit is Always prevented from being boosted.

FIG. 9 is a circuit diagram of the control circuit 8 according to the third embodiment of the present invention. The configuration of the main circuit is the same as in FIG. The circuit configuration of FIG. 9 is almost the same as the circuit configuration of FIG. 7 of the above-described third embodiment, but when the output voltage of the chopper circuit 3 becomes a certain voltage value or more, the ON period of the switching element Q1 of the chopper circuit 3 is increased. In place of the chopper output control unit 15, a stage control unit 17 for performing control for gradually narrowing is provided. The stage controller 17 includes a comparator CP2,
CP3 is provided and a different reference voltage is set for each. In this embodiment, the reference voltage of the comparator CP2 is set lower than the reference voltage of the comparator CP3.
When the output voltage of the chopper circuit 3 becomes higher due to abnormal boosting and becomes higher than the reference voltage of each comparator, the comparators CP2 and CP3 are respectively in order of the comparators CP2 and C3.
Switching elements Q9, Q connected to the output terminal of P3
10 is turned on, the switching element Q of the chopper circuit 3
1 for driving a monostable multivibrator IC1
Since the time constant that determines the ON period of the pulse signal Ve output from 0 is changed by the resistors R17 and R18 connected to the switching elements Q9 and Q10, the ON period of the switching element Q1 is as shown in FIG. As the output voltage of 3 increases, the output voltage gradually decreases. In FIG. 10A, when the switching elements Q9 and Q10 are both off, in FIG. 10B, the switching element Q9 is on,
When the switching element Q10 is off, FIG. 10C shows the waveform of the pulse signal V _BE for driving the on period of the switching element Q1 when both the switching elements Q9 and Q10 are on.

Further, in the circuit configuration of the fourth embodiment shown in FIG. 11, control for gradually narrowing the ON period of the switching element Q1 is performed according to the dimming state of the discharge lamp. In the circuit of FIG. 11, a dimming signal circuit 18 having the same circuit configuration as the dimming signal circuit 16 is provided. For example, when the switch SW2 is turned on, the light output of the discharge lamp L is 60% of that in normal lighting. Switch to dimming state and switch S
When W3 is turned on, the light output of the discharge lamp L is set to 3 at the time of normal lighting.
It is assumed that control is performed so that the 0% dimming state is set. Switch S
When W2 and SW3 are turned on, the switching elements Q9 and Q10 provided in the stage control unit 17 are turned on, and the same control as that of the circuit configuration shown in FIG. 9 is performed.
In this case, the waveform of the pulse signal V _BE during normal lighting is shown in FIG.
(A), the waveform of the pulse signal V _BE at 60% dimming during normal lighting is shown in FIG.
The waveform of the pulse signal V _BE during% dimming is shown in FIG.

Further, in the circuit configuration of the fifth embodiment shown in FIG. 12, the control for gradually narrowing the ON period of the switching element Q1 is performed according to the load abnormality detection state. The circuit of FIG. 12 is provided with a load abnormality detection circuit 19 for detecting an abnormality of the discharge lamp L, which is a load. For example, in the present embodiment, one discharge lamp L is removed and the discharge lamp L is removed. In the state where two lights are removed, the switching elements Q9 and Q1 provided in the stage control unit 17
0 is turned on, and the same control as the circuit shown in FIG. 9 is performed. In this case, the waveform of the pulse signal V _BE at the time of normal lighting is as shown in FIG. 10A, and the waveform of the pulse signal V _BE becomes as shown in FIG.
The waveform of the pulse signal V _BE is shown in FIG.
(C).

Thus, in each of the third to fifth embodiments,
Since the timing of the switching operation of the main switching element of the inverter circuit and the switching element of the chopper circuit is given by a common oscillation circuit, the number of elements used is small, the configuration of the control circuit can be simplified, and the chopper circuit and Since independent control of the inverter circuit can be easily performed, for example, when starting discharge lamp lighting, when controlling the dimming lighting of discharge lamps, when the load is off when multiple discharge lamps are lit in parallel, or when the discharge lamp has reached the end of its life. In the case of load fluctuations such as, by controlling the ON period of the drive signal of the switching element of the chopper circuit stepwise with a simple circuit configuration, it becomes possible to control the DC output voltage of the chopper circuit stepwise, It is possible to prevent the output voltage of the chopper circuit from being boosted abnormally.

FIG. 13 shows a control circuit 8 according to the sixth embodiment of the present invention.
It is a circuit diagram of. The configuration of the main circuit is the same as in FIG.
The circuit configuration of FIG. 13 is almost the same as the circuit configuration of FIG. 7 described above, but when the output voltage of the chopper circuit 3 becomes a certain voltage value or more, the switching element Q of the chopper circuit 3 is turned on.
Instead of the chopper output control unit 15, an intermittent output control unit 20 for controlling the intermittent output of the ON signal V _{BE of} 1 is provided. The output voltage of the chopper circuit 3 is set to the resistance R
7 and R8 to the intermittent output control unit 20, and when the output voltage of the chopper circuit 3 exceeds a certain reference voltage, the ON signal V _BE of the switching element Q1 of the chopper circuit 3 output from the intermittent output control unit 20. Is intermittently output from the output signal of FIG. 14A as shown in FIG. 14B. When the output voltage of the chopper circuit 3 further increases in this state, control is performed to intermittently output the ON signal VBE of the switching element Q1 as shown in FIG. 14C.

Further, in the circuit configuration of the seventh embodiment shown in FIG. 15, the ON signal V of the switching element Q1 described above is used.
_{The BE} is intermittently output according to the dimming state of the discharge lamp. In the circuit of FIG. 15, a dimming signal circuit 18 having the same circuit configuration as the dimming signal circuit 16 is provided. For example, when the switch SW2 is turned on, the light output of the discharge lamp L is 60% of that in normal lighting. In the dimming state, when the switch SW3 is turned on, the light output of the discharge lamp L is controlled to be in the 30% dimming state at the time of normal lighting. For example, when the switch SW2 is turned on, the intermittent on signal V _BE shown in FIG. 14B is output to the switching element Q1.
When the switch SW3 is turned on, the intermittent output control unit 20 performs control such that the intermittent ON signal V _BE shown in FIG. 14C is output to the switching element Q1.

Further, in the circuit configuration of the eighth embodiment shown in FIG. 16, the ON signal V of the switching element Q1 described above is used.
_The control to intermittently output _BE is performed according to the load abnormality detection state. The circuit of FIG. 16 is provided with a load abnormality detection circuit 19 that detects an abnormality of the discharge lamp L that is a load, and intermittently responds to a control signal transmitted from the load abnormality detection circuit 19 in response to a load abnormality. Output control unit 2
0 controls to intermittently output the ON signal V _BE of the switching element Q1. For example, in the present embodiment, when one discharge lamp L is removed, the intermittent ON signal V _BE shown in FIG. 14B is output from the intermittent output control unit 20 to discharge the discharge lamp L.
In the state where two lamps are removed, control is performed so that the intermittent ON signal V _BE shown in FIG. 14C is output from the intermittent output control unit 20.

As described above, in each of the sixth to eighth embodiments, the timing of the switching operation of the main switching element of the inverter circuit and the switching operation of the switching element of the chopper circuit are given by the common oscillation circuit. Since the control circuit configuration can be simplified and the chopper circuit and the inverter circuit can be easily controlled independently, for example, at the time of starting the lighting of the discharge lamp, during the dimming lighting control of the discharge lamp, and the discharge lamp The DC output voltage of the chopper circuit can be easily controlled by intermittently outputting the drive signal of the switching element of the chopper circuit when the load fluctuates when multiple lights are lit in parallel, or when the load changes at the end of life of the discharge lamp. Therefore, it is possible to prevent the output voltage of the chopper circuit from being boosted abnormally.

FIG. 17 is a block circuit diagram of the ninth embodiment of the present invention. In this embodiment, the output voltage VD of the chopper circuit 3 in each of the circuit configurations of the above-described first to eighth embodiments.
C is at least 280 V or less. In the discharge lamp lighting device of the present embodiment shown in FIG. 17, a plurality of resonance circuits 7 for lighting the discharge lamp L are connected in parallel on the output side of the inverter circuit 1 so that the discharge lamp L is lit in parallel. ing. FIG. 18 shows the voltage waveform of each part of the circuit shown in FIG.

In the circuit shown in FIG. 17, the chopper circuit 3
The output voltage VDC output from the inverter unit 1 is converted into a high frequency output voltage Vo1 by the inverter unit 1, and the discharge lamp L is lit at a high frequency. FIG. 18A shows the voltage waveform of the output voltage V _DC output from the chopper circuit 3, and FIG. 18B shows the voltage waveform of the high frequency output voltage Vo 1 output from the inverter unit 1. The high frequency output voltage Vo1 becomes a rectangular wave AC voltage via the DC cutting capacitor C1 and is applied to each resonance circuit 7. Here, when at least one of the plurality of discharge lamps L connected in parallel is removed, the ground voltage Vo2 applied to the terminal of the resonance circuit 7 from which the discharge lamp L is removed is as shown in FIG. 18 (c). become. In addition,
Since there is a stray capacitance C0 between the terminal of the resonance circuit 7 from which the discharge lamp L is removed and the ground, the voltage Vo2 between the ground is shown in FIG.
A resonance waveform as shown in FIG.
The peak voltage of 2 is slightly higher than V _DC / 2.

In domestic lighting equipment, the voltage to ground is 150
When it is V or more, it is obliged to perform ground wiring work on the lighting equipment. Therefore, in any situation, by controlling the output voltage V _DC by the control circuit 8 so that the output voltage V _DC output from the chopper circuit 3 is at least 280 V or less, the ground voltage Vo2 becomes 150 V or more. Can be prevented. The control method of the output voltage V _DC output from the chopper circuit 3 may be the control method of each of the above-described embodiments.

As described above, in this embodiment, in order to prevent the voltage to ground from exceeding 150 V, the output voltage output from the chopper circuit is controlled to be below 280 V, so that the ground wiring is controlled. It is possible to provide a home lighting fixture that requires no construction.

FIG. 19 is a circuit diagram of the control circuit 8 according to the tenth embodiment of the present invention. The configuration of the main circuit is the same as in FIG. The circuit configuration of FIG. 19 is almost the same as the circuit configuration of FIG. 7 described above, but a load abnormality detection circuit 19 for detecting an abnormality of the discharge lamp L as a load is provided, and a load abnormality (for example, no load) is provided. The switching element Q11 connected to the load abnormality detection circuit 19 is turned on according to the load), and the switching element Q1 of the chopper circuit 3 output from the control circuit 8 is output.
Is configured to stop the drive signal of.

As described above, in this embodiment, since the timing of the switching operation of the main switching element of the inverter circuit and the switching operation of the switching element of the chopper circuit are given by the common oscillation circuit, the number of used elements is small and the control circuit is small. Since the configuration of can be simplified and the chopper circuit and the inverter circuit can be easily controlled independently, for example,
The DC output voltage of the chopper circuit should be adjusted when the discharge lamp is started, when controlling the dimming lighting of the discharge lamp, when the load is off when multiple discharge lamps are lit in parallel, or when the load changes during the end of life of the discharge lamp. It becomes possible to control with a simple circuit configuration, and it is possible to prevent the output voltage of the chopper circuit from being abnormally boosted by stopping the drive signal of the switching element of the chopper circuit according to the abnormality of the load. .

[0046]

According to the invention of claim 1, the output voltage of the rectifier circuit connected to the AC power source is chopped by turning on and off the switching element, and the chopping voltage is rectified and smoothed to be converted into a predetermined DC voltage. In addition, the step-up chopper circuit that suppresses the distortion of the input current waveform and the switching element connected in series to the output of the step-up chopper circuit are alternately turned on / off to supply high-frequency power to the load via the LC resonance circuit. And an inverter circuit for supplying the
By providing the timing of the switching operation of the switching elements of the main switching element and the chopper circuit of the inverter circuit by a common oscillator circuit, so as to interlock control the drive signal of each of the switching elements of the step-up chopper circuit and an inverter circuit Therefore, the number of used elements is small, and the configuration of the control circuit can be simplified. In addition, the oscillation output of the oscillation circuit
Drive signal of switching element of inverter circuit
A first monostable multivibrator for generating a signal;
Triggered by the oscillation output of the oscillator circuit
Second generation of a drive signal for the switching element of the Par circuit
The monostable multivibrator of
The oscillation frequency can be changed according to the load condition of the inverter circuit.
And the pulse of the second monostable multivibrator
The width can be changed according to the output voltage of the boost chopper circuit.
So, while using a common oscillator circuit,
Easy independent control of chopper circuit and inverter circuit
There is an effect that can be realized.

According to the invention of claim 2, claim 1
In the inverter device, if the output voltage of the step-up chopper circuit tends to increase according to the load condition, the ON section of the switching element of the step-up chopper circuit is controlled in the decreasing direction, so the number of used elements is reduced. Since the control circuit configuration can be simplified and the chopper circuit and the inverter circuit can be easily controlled independently, for example, when the discharge lamp is started to be lit, the dimming lighting control of the discharge lamp is controlled, and the discharge lamp is often used. It is possible to control the DC output voltage of the chopper circuit to be almost constant with a simple circuit configuration when the load is off during parallel lighting of the lamps or when the load changes during the end of life of the discharge lamp. There is an effect.

According to the invention of claim 3, claim 2
In the above inverter device, the drive signal of each switching element of the step-up chopper circuit and the inverter circuit is interlocked and controlled so that the ON section of the switching element of the step-up chopper circuit is equal to or less than the ON section of the switching element of the inverter circuit. Since the number of elements used is small, the configuration of the control circuit can be simplified, and the chopper circuit and the inverter circuit can be easily controlled independently.For example, when starting the lighting of the discharge lamp, the dimming of the discharge lamp is performed. During lighting control, when the load is off when multiple discharge lamps are lit in parallel,
It is possible to control the DC output voltage of the chopper circuit to be almost constant with a simple circuit configuration when the load fluctuates at the end of life of the discharge lamp, and to turn on the switching elements of the chopper circuit. Since the period is equal to or less than the ON period of the switching element of the inverter circuit, it is possible to prevent the output voltage of the chopper circuit from being abnormally boosted.

According to the invention of claim 4, claim 1
In the inverter device, if the output voltage of the boost chopper circuit tends to increase according to the load condition, the ON section of the switching element of the boost chopper circuit is controlled to be decreased step by step. Since the number of elements is small, the configuration of the control circuit can be simplified, and the chopper circuit and the inverter circuit can be easily controlled independently, for example, when starting the lighting of the discharge lamp, when controlling the dimming lighting of the discharge lamp, To control the ON period of the drive signal of the switching element of the chopper circuit step by step with a simple circuit configuration when the load is off when multiple electric lights are lit in parallel and when the load fluctuates at the end of life of the discharge lamp. This makes it possible to control the DC output voltage of the chopper circuit step by step and prevent the output voltage of the chopper circuit from being abnormally boosted. There is.

According to the invention of claim 5, claim 1
In the inverter device, if the output voltage of the boost chopper circuit tends to increase depending on the load condition, the ON period of the switching element of the boost chopper circuit is intermittently reduced and controlled. Since the number of elements is small, the configuration of the control circuit can be simplified, and the chopper circuit and the inverter circuit can be easily controlled independently, for example, when starting the lighting of the discharge lamp, when controlling the dimming lighting of the discharge lamp, By intermittently outputting the drive signal of the switching element of the chopper circuit, the DC output voltage of the chopper circuit can be output when the load is off during the parallel lighting of multiple electric lights, or when the load changes during the end of life of the discharge lamp. It is possible to easily control, and it is possible to prevent the output voltage of the chopper circuit from being boosted abnormally.

According to the invention of claim 6, claim 2
In the inverter device of Nos. 5 to 5, the on-state voltage of the switching element of the step-up chopper circuit is controlled so that the output voltage of the step-up chopper circuit becomes 280 V or less according to the state of any load. 1
It is possible to prevent the voltage from becoming 50 V or higher, and it is possible to provide a home lighting fixture that does not require ground wiring work.

According to the invention of claim 7, claim 6
In the above inverter device, when the load condition decreases below a predetermined level, only the step-up chopper circuit is controlled to stop the drive signal of the switching element, so the number of elements used is small and the control circuit configuration is small. Since it can be simplified and the independent control of the chopper circuit and the inverter circuit can be easily performed, for example, when starting the lighting of the discharge lamp, when controlling the dimming lighting of the discharge lamp, and when the multiple lamps of the discharge lamp are lit in parallel, the load can be increased. The DC output voltage of the chopper circuit can be controlled with a simple circuit configuration when the load fluctuates, such as when the lamp is disconnected or when the discharge lamp is at the end of its life.In addition, switching of the chopper circuit can be performed depending on the load abnormality. By stopping the drive signal of the element, it is possible to prevent the output voltage of the chopper circuit from being abnormally boosted.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a basic configuration example of a main circuit of an inverter device of the present invention.

FIG. 2 is a circuit diagram showing a basic configuration example of a control circuit of the inverter device of the present invention.

FIG. 3 is a waveform diagram for explaining the operation of the inverter device of the present invention.

FIG. 4 is a circuit diagram showing a configuration of a main circuit of the first embodiment of the present invention.

FIG. 5 is a circuit diagram showing a configuration of a control circuit according to a first embodiment of the present invention.

FIG. 6 is a waveform diagram for explaining the operation of the first embodiment of the present invention.

FIG. 7 is a circuit diagram showing a configuration of a control circuit according to a second embodiment of the present invention.

FIG. 8 is a waveform diagram for explaining the operation of the second embodiment of the present invention.

FIG. 9 is a circuit diagram showing a configuration of a control circuit according to a third embodiment of the present invention.

FIG. 10 is a waveform diagram for explaining the operation of the third embodiment of the present invention.

FIG. 11 is a circuit diagram showing a configuration of a control circuit according to a fourth embodiment of the present invention.

FIG. 12 is a circuit diagram showing a configuration of a control circuit according to a fifth embodiment of the present invention.

FIG. 13 is a circuit diagram showing a configuration of a control circuit according to a sixth embodiment of the present invention.

FIG. 14 is a waveform diagram for explaining the operation of the sixth embodiment of the present invention.

FIG. 15 is a circuit diagram showing a configuration of a control circuit according to a seventh embodiment of the present invention.

FIG. 16 is a circuit diagram showing a configuration of a control circuit according to an eighth embodiment of the present invention.

FIG. 17 is a circuit diagram showing a configuration of a ninth exemplary embodiment of the present invention.

FIG. 18 is a waveform chart for explaining the operation of the ninth embodiment of the present invention.

FIG. 19 is a circuit diagram showing a configuration of a control circuit according to a tenth embodiment of the present invention.

FIG. 20 is a circuit diagram of a first conventional example.

FIG. 21 is a circuit diagram of a second conventional example.

[Explanation of symbols]

AC AC power supply 1 Inverter circuit 2 rectifier circuit 3 Step-up type chopper circuit

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-8-124687 (JP, A) JP-A-8-237957 (JP, A) JP-A-8-275543 (JP, A) JP-A-8- 126345 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02M 7/538 H02M 3/155 H02M 7/217 H02M 7/48

Claims (7)

(57) [Claims] 1. A booster for chopping an output voltage of a rectifier circuit connected to an AC power source by turning a switching element on and off, rectifying and smoothing the chopping voltage to convert it into a predetermined DC voltage, and suppressing an input current waveform distortion. Type chopper circuit, and an inverter circuit for alternately turning on and off switching elements connected in series to the output of the boost type chopper circuit to supply high-frequency power to a load via an LC resonance circuit. And the load state of the inverter circuit as means for interlocking control of the drive signal of each switching element of the inverter circuit.
One oscillation circuit whose oscillation frequency is variable according to
It is triggered by the oscillation output of this oscillator circuit
For generating a drive signal for the switching element of the switching circuit
Monostable multivibrator and oscillation output of the oscillation circuit
Switch of boost type chopper circuit triggered by
Second monostable multi-bi converter for generating a driving signal for the switching element
The pulse of the vibrator and the second monostable multivibrator
The width can be changed according to the output voltage of the boost chopper circuit.
Inverter apparatus comprising: a means that. 2. The inverter device according to claim 1,
An inverter device characterized in that if the output voltage of the booster chopper circuit tends to increase according to the state of the load, the ON section of the switching element of the booster chopper circuit is controlled in a decreasing direction. 3. The inverter device according to claim 2, wherein
An inverter characterized in that the drive signals of the switching elements of the booster chopper circuit and the inverter circuit are interlocked so that the ON duration of the switching element of the booster chopper circuit is equal to or less than the ON duration of the switching element of the inverter circuit. apparatus. 4. The inverter device according to claim 1,
An inverter device characterized in that if the output voltage of a step-up chopper circuit tends to increase according to the state of a load, the ON section of a switching element of the step-up chopper circuit is gradually reduced and controlled. 5. The inverter device according to claim 1,
An inverter device characterized in that if the output voltage of a boost chopper circuit tends to increase according to the state of a load, the ON section of a switching element of the boost chopper circuit is intermittently reduced and controlled. 6. The inverter device according to any one of claims 2 to 5, wherein the on-section of the switching element of the step-up chopper circuit is controlled so that the output voltage of the step-up chopper circuit becomes 280 V or less according to the state of any load. Characteristic inverter device. 7. The inverter device according to claim 6,
An inverter device characterized in that, when a load condition decreases below a predetermined level, only a boost chopper circuit is controlled to stop a drive signal of a switching element.