JPH10106786A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost by utilizing the switching operation of an inverter circuit applying almost square wave voltage synchronized with a commercial AC power supply to a load also as the switching operation of a step-up circuit for improving power factor and input wave form and conducting step-up operation. SOLUTION: A power supply device has a commercial AC power supply AC to which a high frequency cut filter 1 is connected, an inductor L1 , a primary winding N1 of a transformer T, at least one rectifier element, a first closed loop to which the rectifier element and a capacitor C1 are connected in series, the capacitor C1 , a switching element, a secondary winding N2 of a transformer T, and a second closed loop to which the secondary winding N2 and a load Z are connected in series, and a capacitor C2 is connected in parallel to the load Z. At least one switching element is switched at higher frequency than power frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device suitable for powering a high-pressure discharge lamp.

[0002]

2. Description of the Related Art Conventionally, there has been known a discharge lamp lighting device for lighting a discharge lamp using an inverter device. In this type of apparatus, a DC voltage is obtained from an AC power supply, the DC voltage is supplied as power to the inverter apparatus, and the discharge lamp is turned on by the output of the inverter apparatus. Conventionally, a capacitor input type rectifier circuit has been used as a means for obtaining a DC voltage from an AC power supply. However, since an input current waveform contains a harmonic component and a power factor is reduced, many troubles occur. Therefore, many inventions have been made to make the input current waveform close to a sine wave and increase the power factor.

Japanese Patent Publication No. 5-9918 filed by the Company is an example of this, and examples of a conventional capacitor input type and the like are also described in detail. In this patent, a high frequency voltage is applied to a transformer by an operation inside an inverter,
This is added to the input voltage at the diode bridge so that the input current flows even when the input voltage is low, so that the input current waveform approaches a sine wave. However, this patent does not specifically describe the circuit of the inverter portion. Accordingly, Japanese Patent Application Laid-Open No. H5-222749 has filed an application to improve the input power factor by applying a high-frequency voltage to a transformer as in this patent.

[0004] However, both of the above applications assume that the output of the inverter is a high-frequency voltage. Therefore, it cannot be easily used as an inverter for lighting a high-pressure discharge lamp. This is because when the high-pressure discharge lamp is lit at a frequency of several KHz or more, an acoustic resonance phenomenon occurs, and it is difficult to perform stable lighting.

On the other hand, a lighting device for a high pressure discharge lamp generally uses a rectangular wave type inverter as shown in FIG. This circuit includes a high-frequency cut filter 1, a booster circuit 2, and an inverter circuit 3. The inverter circuit 3 applies a rectangular wave output to a load Z,
The input power factor is improved by the chopper operation of the booster circuit 2.

FIG. 9 shows operation waveforms of this circuit. The switching element Q ₁ is being turned on and off at a high frequency, switching the element Q ₁ is turned on, commercial power supply high-frequency cut filter 1 from AC, diode D ₁ to D ₄ of the current in the inductor L ₁ through the rectifier bridge is flowing, energy is stored in inductor L _1. When the switching element Q ₁ is turned off, electromotive force in the inductor L ₁ is induced, a voltage obtained by superimposing a full-wave rectified output is charged in the capacitor C ₁ through the diode D _5. Thus, the voltage Vdc which is boosted is obtained in the capacitor C _1. Further, since the input current Iin of the rectifier bridge always flows, the input power factor is improved, and the input current Iac from the AC power supply AC is shaped similar to the input voltage Vac by shaping the waveform with the high frequency cut filter 1. And the input waveform distortion is reduced. DC voltage V obtained in the capacitor C ₁
dc is applied to the input terminal of the full bridge inverter circuit 3 consisting of a switching element Q ₂ to Q _5. The switching elements Q ₄ and Q ₅ are alternately turned on and off at a low frequency as shown in FIG. When the switching element Q ₅ is turned on, the switching element Q ₃ are turned off, the switching element Q ₂ is turned on and off at a high frequency. Further, when the switching element Q ₄ is ON, the switching element Q ₂ is turned off, the switching element Q ₃ are turned on and off at a high frequency. A load Z is connected to an output terminal of the full-bridge inverter circuit 3 via a low-pass filter including an inductor L ₂ and a capacitor C ₂ , and high-frequency components are blocked by the inductor L ₂ and bypassed by the capacitor C _2. Therefore, the load voltage Vz becomes a rectangular wave voltage, and the load current Iz becomes a rectangular wave current.

[0007]

In the lighting device for a high-pressure discharge lamp as shown in FIG. 8, the power factor is improved by the boosting circuit 2, the input waveform is improved and the boosting operation is performed. In order to perform the inverter operation and the power adjustment operation for lighting the rectangular wave by the control unit 3, it is necessary to separately control the booster circuit 2 and the inverter circuit 3, and it is necessary to provide a control circuit separately.

An object of the present invention is to provide a switching operation of an inverter circuit for performing an inverter operation and a power adjustment operation by using a coupling between a primary winding and a secondary winding of a transformer. Another object of the present invention is to provide a power supply device which does not require a switching element for improving a power factor, improving an input waveform, and performing a boosting operation, thereby enabling cost reduction.

[0009]

According to the present invention, in order to solve the above-mentioned problems, as shown in FIG. 1, a commercial AC power supply AC to which a high frequency cut filter 1 is connected, and an inductor L _1. A first closed loop in which a primary winding N ₁ of a transformer T, at least one rectifying element, and a first capacitor C ₁ are connected in series; and the first capacitor C ₁ , A second closed loop in which two switching elements, a secondary winding N _{2 of the} transformer T, and a load Z are connected in series, and the first capacitor C ₁
A power supply device comprising a _second capacitor C2 connected so as to be substantially in parallel with the load Z, wherein at least one of the switching elements is higher than a commercial frequency. A high frequency voltage is generated by switching at a high frequency, and a commercial AC power supply A
The switching operation is performed such that a substantially rectangular wave voltage synchronized with C is applied.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.
As an embodiment, the embodiment of FIGS. 1 to 7 is shown. First, Figure 1 shows a book
FIG. 2 is a circuit diagram of a first embodiment of the present invention, and FIG.
You. In this embodiment, the connection of the high-frequency cut filter 1 is described.
Commercial AC power supply AC and inductor L ₁And a transformer
Primary winding N of T₁Are connected in series to the full-wave rectifier.
Connect to the AC input terminal and connect to the DC output terminal of the full-wave rectifier.
Capacitor C for smoothing wave rectified voltage₁And connect
This first capacitor C₁DC voltage to AC voltage
Full-bridge inverter circuit 3 with switching element
Q_Two~ Q_FiveAnd the AC output of the inverter circuit 3
The secondary winding N of the transformer T_TwoAnd load Z in series
And a second capacitor C in parallel with the load Z._Two
A power supply device comprising:
3 switching element Q_Two~ Q_FiveAt least one of
More than one element Q_Two, Q_ThreeThe frequency higher than the commercial frequency
To generate high frequency voltage by switching
A substantially rectangular wave voltage synchronized with the commercial AC power supply AC to the load Z
So that the switching element of the inverter circuit 3
Q_Two~ Q _FiveIs operated.

This circuit comprises a high-frequency cut filter 1,
The high frequency cut filter 1 and the inverter circuit 3 are composed of a booster circuit 2 and an inverter circuit 3.
Performs the same operation as. Here, as shown in the figure, if a primary winding N ₁ and a secondary winding N ₂ are arranged in series with the load Z before the diode bridge, the elements of the inverter circuit 3 are turned on / off. RF voltage is applied to the secondary winding N _2. Thereby, the primary winding high-frequency voltage is generated in N _1, the high-frequency current flows through the inductor L _1. Thus, in the step-up circuit 2, together with the high-frequency current flows having a peak value corresponding to the input voltage, performs boosting effect to charge a voltage higher than the peak value of the AC power source AC to the capacitor C _1. The high-frequency cut filter 1 allows a small amount of high-frequency current to flow on the AC power supply AC side, thereby improving the power factor. The voltage and synchronization of the operation of this operation the inverter circuit 3 is an AC power source, is accomplished by the same phase, the primary winding N ₁ and the secondary winding direction of the N ₂ current both power and synchronization inversion By doing so, a good operation is obtained. Note that the waveform of the input current can be changed from a trapezoidal shape to a waveform having a small conduction angle depending on the turns ratio of the transformer T, and accordingly, the waveform becomes a rectangular wave with irregularities.

With the configuration described above, there is no need to operate the booster circuit 2 with a switching element as in the circuit of FIG. 8 of the conventional example, so that a control circuit is not required, the cost is reduced, and the input power factor is reduced. This can be improved, and the power supply and the output are synchronized, so that unnecessary beats do not occur and light does not flicker. Also, if substituted for the primary winding N ₁ and the series inductance component in the leakage inductance of the transformer T, it is evident that it is optional. The same applies to the following embodiments.

FIG. 3 is a circuit diagram of a second embodiment of the present invention, and FIG.
Shows the operation waveform. This embodiment, in the connected AC voltage AC high-frequency cut filter 1 is connected to the rectifier circuit, to the rectified output, the inductor L _1, a primary winding N ₁ of the transformer T, a first capacitor the C ₁ to form a first closed loop connected in series, a capacitor C ₁ of the first, the first switching element Q _1, and the secondary winding N ₂ of the transformer T, load Z to the output terminal A second closed loop is formed in series with the input terminal of the inverter circuit 3 to which the second capacitor C _{2 is} connected in parallel with the load Z at the input terminal of the inverter circuit 3. a power supply apparatus formed by connecting, with generating a high frequency voltage to the first switching element Q ₁ by switching at a frequency higher than the commercial frequency, substantially square wave synchronized with the AC voltage AC to a load Z Apply voltage As, in which to perform the switching operation of the inverter circuit 3. The first switching element Q ₁ and the first
The two ends of the series circuit of the capacitor C _1, the diode D ₅ for flowing the regenerative current of the transformer T are connected.

This circuit corresponds to the inverter circuit 3 of the first embodiment.
The part that performs the pressure-lowering action is taken out from the inside.
Therefore, the part of the inverter circuit 3 according to the second embodiment only reverses the polarity at a low frequency.
It is configured to perform step-up and step-down operations around ₁ . The operation, the switching element Q ₁ is performs switching at a high frequency, as well as adjusting the power applied to the lamp by applying a high frequency voltage in the secondary winding N _2, performs the boosting operation. In this circuit, since the portion of the inverter circuit 3 are independent, seemingly, the operating frequency of the inverter circuit 3 is considered like so that it can freely set the phase, and capacity of the capacitor C _1, the number of turns of the transformer T Since the commercial frequency may be superimposed on the output depending on the ratio or the like, it is necessary to perform an inverter operation synchronized with the power supply.

With the above configuration, a high-frequency input current corresponding to the input AC power supply voltage flows, and the input power factor can be improved by filtering the input current. A stable output can be taken out without causing it. Also, compared to the first embodiment, the number of switching elements operating at a high frequency is small, and the diode bridge may be of a low speed, so that the cost can be reduced.

FIG. 5 is a circuit diagram of a third embodiment of the present invention.
This embodiment is formed by connecting a rectifier circuit connected to the AC voltage AC high-frequency cut filter 1, in the rectified output, an inductor L1, a primary winding N ₁ of the transformer T,
The first capacitor C ₁ form a first closed loop connected in series, and the first capacitor C _1, the switching element Q _1, and connecting the secondary winding N ₂ of the transformer T in series chopper forming a second closed loop, releasing the switching element Q ₁ is accumulated in the transformer T during the on energy, the switching element Q ₁ is via the diode D ₅ when off the load Z A circuit is configured, an inverter circuit 3 for polarity inversion is connected between the output terminal of the chopper circuit and the load Z, and an input terminal of the inverter circuit 3 is substantially parallel to the load Z so as to be substantially parallel to the load Z. connect 2 of the capacitor C _2, together to generate a high frequency voltage to the switching element Q ₁ by switching at a frequency higher than the commercial frequency, synchronized with the AC voltage AC to a load Z To apply a rectangular wave voltage, in which to perform the switching operation of the inverter circuit 3.

In this circuit, the boosting circuit 2 has a configuration in which a step-up chopper and a step-up / step-down inverting chopper are combined, and the other parts are the same as those in the second embodiment. The same applies to the operation, and the operation is performed so as to synchronize with the AC power supply.
With this configuration, a high-frequency current corresponding to the input AC power supply voltage flows, and the input power factor can be improved by filtering the current, and by synchronizing, the input and output frequency can be reduced. A stable output can be obtained without generating a beat due to the difference. Further, compared to the first embodiment, the number of switching elements operating at a high frequency is small, and the diode bridge may be of a low speed, so that the cost can be reduced.

FIG. 6 shows a circuit diagram of a fourth embodiment of the present invention. In this embodiment, a series circuit of first and second capacitors C ₁₁ and C ₁₂ is connected in parallel to a series circuit of first and second switching elements Q ₂ and Q ₄ .
And the series circuit of the second diodes D ₁ and D ₂ are connected in anti-parallel, and the connection point between the first and _second diodes D ₁ and D ₂ and the first and second capacitors C ₁₁ and C ₁₂ are connected. between points, and commercial AC power source AC to the connected high-frequency cut filter 1, the inductor L _1, 1 winding N of the transformer T
₁ in series and the first and second capacitors C ₁₁ ,
The connection point of C ₁₂ and the first and second switching elements Q ₂ ,
Between the connection point of Q _4, 2 windings N of the transformer T
_2, connect the series circuit of the load Z, a power supply unit connected third capacitor C ₂ in parallel with the load Z, switching the switching element Q _2, Q ₄ at a higher frequency than the commercial frequency Then, load the commercial AC power supply AC
A substantially rectangular wave voltage synchronized with the above is applied.

In this circuit, the booster circuit 2 is constituted by a half-wave rectifier circuit, and charges two capacitors C ₁₁ and C ₁₂ . Then, the two capacitors C ₁₁ and C ₁₂
, The inverter circuit 3 has a half-bridge configuration. In the operation of this circuit, the switching element Q ₂ is ON / OFF at a high frequency, the operation of the switching element Q ₄ is OFF, the switching element Q ₄ is ON / OFF at a high frequency in the reverse, the switching element Q ₂ The OFF operation is performed alternately in synchronization with the AC power supply. The secondary winding N ₂ by ON / OFF of the device high frequency voltage is applied, performs a boosting operation in the boosting circuit 2. This also improves the power factor in the same manner as in the previous embodiment. A substantially rectangular wave voltage is applied to the discharge lamp as a load.

With the above-described configuration, it is synchronized with the AC power supply.
By performing the operation, while improving the input power factor,
A stable output without a beat can be obtained. Also,
With this configuration, a no-load secondary voltage can be obtained with a half-wave of an AC power supply.
Can be used, for example, a device suitable for 200V
It is. The winding direction of the transformer T in FIG.
Aether D₁Are conducting, and the switching element Q_TwoBut
This is the direction when performing ON / OFF switching operation.
The winding direction is reversed, the diode D ₁Is conductive
The switching element Q_FourIs ON / OFF switch
It is also possible to perform the switching operation.

FIG. 7 is a circuit diagram of a fifth embodiment of the present invention.
In this embodiment, a series circuit of first and second capacitors C ₁₁ and C ₁₂ is connected to an input terminal, and a full-bridge inverter circuit 3 that converts an input DC voltage into an AC voltage and outputs the converted AC voltage is connected to switching elements Q ₂ to Q ₂ . constituted by Q _5, the input terminal of the inverter circuit 3, the first and second diodes D _1,
A series circuit of a D ₂ in inverse parallel, between the connection point of the first and second diodes D _1, D ₂ of the connection point and the first and second capacitors C _11, C _12, high-frequency cut Filter 1
A commercial AC power source AC to the connected, and an inductor L _1,
Connect the primary winding N ₁ and the transformer T in series to connect the series circuit of the secondary winding N ₂ and the load Z of the transformer T to AC output terminals of the inverter circuit 3, parallel to the load Z to a power supply apparatus formed by connecting the third capacitor C _2, the switching element Q ₂ of the inverter circuit 3 to Q
₅ of the inverter circuit 3 so as to generate a high-frequency voltage by switching at least one element at a frequency higher than the commercial frequency, and to apply a substantially rectangular wave voltage synchronized with the commercial AC power supply to the load Z. it is obtained so as to operate the switching element Q ₂ to Q _5.
In this circuit, the booster circuit 2 of the first embodiment is configured to perform voltage doubler rectification. The operation and the like are the same as those of the first embodiment, and the same effects can be obtained. In addition, contrary to the fourth embodiment, the inverter circuit can be operated with the doubled voltage.
Suitable for V-system equipment.

[0022]

According to the present invention, a switching element for improving a boosting operation and an input power factor is not required, cost can be reduced, and the inverter can be operated in synchronization with the power supply voltage so that the power supply voltage and the inverter can be reduced. Can suppress the occurrence of a beat due to the difference in the operating frequencies of the above, and can supply stable power. Further, according to the third to fifth aspects, the number of switching elements operating at a high frequency is small, and the speed of the diode bridge may be low, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram of the first embodiment of the present invention.

FIG. 3 is a circuit diagram of a second embodiment of the present invention.

FIG. 4 is an operation waveform diagram of the second embodiment of the present invention.

FIG. 5 is a circuit diagram of a third embodiment of the present invention.

FIG. 6 is a circuit diagram of a fourth embodiment of the present invention.

FIG. 7 is a circuit diagram of a fifth embodiment of the present invention.

FIG. 8 is a circuit diagram of a conventional example.

FIG. 9 is an operation waveform diagram of a conventional example.

[Explanation of symbols]

1 high-frequency cut filter 2 booster circuit 3 inverter circuit T trans N ₁ 1 winding N ₂ 2 winding C ₁ first capacitor C ₂ second capacitor L ₁ inductor

Claims (8)

[Claims] 1. A commercial AC power supply to which a high frequency cut filter is connected, an inductance element, and a transformer.
A first closed loop in which a secondary winding, at least one rectifying element, and a first capacitor are connected in series; the first capacitor, at least one switching element, and a secondary winding of the transformer And a second closed loop in which a load is connected in series, and a power supply device comprising a second capacitor connected to the first capacitor so as to be substantially parallel to the load. Wherein at least one of the switching elements is switched at a frequency higher than a commercial frequency to generate a high-frequency voltage, and a substantially rectangular wave voltage synchronized with a commercial AC power supply is applied to a load. A power supply device that performs a switching operation. 2. A commercial AC power supply to which a high frequency cut filter is connected, an inductance element, and a transformer.
A circuit having a secondary winding connected in series is connected to an AC input terminal of the full-wave rectifier, and a first capacitor for smoothing the full-wave rectified voltage is connected to a DC output terminal of the full-wave rectifier. A switching element constitutes a full-bridge inverter circuit for converting a DC voltage into an AC voltage, and a series circuit of a secondary winding of the transformer and a load is connected to an AC output terminal of the inverter circuit. A power supply device connected to the second capacitor, wherein at least one of the switching elements of the inverter circuit is switched at a frequency higher than a commercial frequency to generate a high-frequency voltage, and The switching element of the inverter circuit is operated so as to apply a substantially rectangular wave voltage synchronized with the AC power supply. The power supply device according. 3. A rectifier circuit comprising: a rectifier circuit connected to a commercial AC power supply to which a high-frequency cut filter is connected; and an inductor element, a primary winding of a transformer, and a first capacitor connected in series to the rectified output. A first closed loop of the first capacitor, a first switching element,
A second closed loop is formed in which a secondary winding of the transformer and an input terminal of an inverter circuit having a load connected to an output terminal are connected in series, and the input terminal of the inverter circuit is substantially parallel to the load. A power supply device connected to a second capacitor, wherein the first switching element is switched at a frequency higher than a commercial frequency to generate a high-frequency voltage, and a load is synchronized with the commercial AC power supply. A switching operation of the inverter circuit so as to apply the substantially rectangular wave voltage. 4. The power supply according to claim 3, wherein a diode for flowing a regenerative current of the transformer is connected to both ends of a series circuit of the first switching element and the first capacitor. apparatus. 5. A rectifier circuit comprising: a rectifier circuit connected to a commercial AC power supply to which a high-frequency cut filter is connected; and an inductor element, a primary winding of a transformer, and a first capacitor connected in series to the rectified output. 1 to form a second closed loop in which the first capacitor, the switching element, and the secondary winding of the transformer are connected in series, and the switching element is connected to the transformer while the switching element is on. Forming a chopper circuit for discharging the stored energy to a load via a diode when the switching element is turned off, connecting an inverter circuit for polarity inversion between an output terminal of the chopper circuit and the load, A second capacitor connected to an input terminal of the inverter circuit so as to be substantially parallel to a load; Together to generate a high frequency voltage by switching at high frequencies,
A power supply device, wherein a switching operation of an inverter circuit is performed so that a substantially rectangular wave voltage synchronized with a commercial AC power supply is applied to a load. 6. A series circuit of first and second capacitors is connected in parallel to a series circuit of first and second switching elements, and a series circuit of first and second diodes is connected in anti-parallel. A commercial AC power supply having a high frequency cut filter connected between a connection point of the first and second diodes and a connection point of the first and second capacitors, an inductance element, and a primary winding of a transformer. A series circuit of the secondary winding of the transformer and a load is connected between a connection point of the first and second capacitors and a connection point of the first and second switching elements. A third capacitor connected in parallel with the load, wherein the switching element is switched at a frequency higher than a commercial frequency to apply a substantially rectangular wave voltage synchronized with the commercial AC power to the load. A power supply unit characterized in that: 7. A full-bridge inverter circuit connected to an input terminal of a series circuit of first and second capacitors and configured by a switching element for converting an input DC voltage into an AC voltage and outputting the converted AC voltage, wherein an input of the inverter circuit is provided. At the end, a series circuit of first and second diodes is connected in anti-parallel, and a high frequency cut filter is connected between the connection point of the first and second diodes and the connection point of the first and second capacitors. Connecting a connected commercial AC power supply, an inductance element, and a primary winding of a transformer in series, connecting a series circuit of a secondary winding of the transformer and a load to an AC output terminal of the inverter circuit, 3rd in parallel with load
A power supply device, comprising: connecting at least one of the switching elements of the inverter circuit at a frequency higher than a commercial frequency to generate a high-frequency voltage; A power supply device wherein a switching element of an inverter circuit is operated so as to apply a substantially rectangular wave voltage synchronized with a power supply. 8. The power supply device according to claim 1, wherein an inductance element connected in series with a primary winding of the transformer is constituted by a leakage inductance of the transformer.