JP3336134B2 - Power supply - Google Patents

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 having improved input current distortion.

[0002]

2. Description of the Related Art Conventionally, there is a power supply device that converts a DC obtained by rectifying and smoothing an AC power supply into a high-frequency AC by turning on / off a switching element including a semiconductor switching element and supplying the AC to a load. In order to improve the distortion of the input current in such a power supply device, various circuit systems have been proposed in which the input current waveform is made substantially the same as the power supply voltage waveform.

One of them is disclosed in US Pat. No. 5,313,142.
There is a number. Figure 6 shows the prior art circuit, this prior art circuit, is connected to a part of the inverter unit 1 to the one end of the AC power source AC through a capacitor C _4. The inverter unit 1 feeds high-frequency energy back to the AC power supply AC side via the capacitor C ₄ , so that the diode bridge D
Causing a high-frequency voltage to the choke L _1A which is connected between the AC power source AC and the diode bridge DB via B, by the high-frequency voltage in all sections of the input voltage, connected to the output terminal of the diode bridge DB charges the capacitor C ₂ consisting of an electrolytic capacitor with Te, the input current is controlled in such a substantially sinusoidal.

The conventional circuit will be further described.
The data section 1 includes a capacitor C_TwoConnected in parallel to
Transistor Q₁, Q_TwoSeries circuit and resonance choke L
_TwoAnd the resonance capacitor C₆Composed of and as load
Is the discharge lamp LP to the condenser C _FourAnd capacitor C_ThreeContact with
Connection point and transistor Q₁And transistor Q_TwoConnection with
The resonance choke L_TwoAnd a return transformer
It is connected via the primary winding of T. The discharge lamp LP
Filament F₁, F_TwoPositive on the non-power supply end of
Characteristic thermistor PTC and capacitor C₇Series circuit with
Are connected. Transistor Q₁, Q_TwoIs a tran
S₁Feedback winding W₁, W_TwoDriven by self-excited circuit
And each transistor Q₁, Q_TwoThe base circuit of the resistor R
_Three, Capacitor C₉Or R_Four, Capacitor C_TenBy
It is configured. Transistor Q₁Base
Anti-R₇, R₆, R_Two, R_Five, Capacitor C₁₁,
Q_ThreeBase current at startup
It is being supplied.

[0005] The resonance loop of the inverter 1 has a capacitor C _3, one end of the AC power source AC through a capacitor C ₄ to one end of the capacitor C ₃ is connected. This conventional example improving the input current distortion in the high frequency voltage through the through part to supply high-frequency energy to the power supply circuit with a capacitor C _4, the choke L _1A causes a high frequency voltage to the diode bridge DB of the resonant circuit It was done.

[0006] That crest a in (at pulsating waveform), the capacitor voltage of the AC power supply AC low-frequency through the capacitor C ₄ is the inverter unit 1 power supply AC voltage waveform shown in FIG. 7 (a) The voltage is applied to one end of C ₃ , and at the valley b (in the pulsating waveform), the inverter 1
One end voltage of the capacitor C ₃ through resonance of but high frequencies inverted, is fed back and the high-frequency voltage to the AC power supply AC side via the capacitor C _4. Therefore AC power supply A
Degree change of capacitor C ₄ with the ridges a and valley portions b of C pulsating waveform come involved to the inverter unit 1, the operation mode of the two inverter unit 1 is present at the crest a and valleys b As a result, the waveform of the load current becomes a current waveform (b) as shown in FIG .

The output of the load current waveform (b) is maximum at a valley b of the AC power supply AC voltage and minimum at a valley a.
It has a waveform similar to that of the AC power supply AC voltage. Such a conventional circuit has a problem that the rush current value at the time of turning on the power is high. U.S. Pat. No. 5,223,767 employs a similar circuit system. This conventional example,
One end of the AC power supply or one end of the output of the rectifying diode bridge of the AC power supply is connected to the inverter section via an impedance element, and the high frequency operation of the inverter section is connected to the choke provided on the input side of the AC power supply via the impedance. Generate a high-frequency voltage, charge the smoothing electrolytic capacitor via a diode bridge at high frequency,
The input current is caused to flow in almost the entire section of the AC power supply voltage.

Another means for improving the distortion of the input current is disclosed in Japanese Patent Application Laid-Open No. Sho 59-222008. In this conventional example, as shown in FIG. 8 , instead of connecting a smoothing capacitor between the output terminals of the diode bridge DB, a part of the high-frequency voltage of the inverter unit 1 is superimposed on the output voltage of the diode bridge DB. The power supply unit 3 is provided. The inverter unit 1 used in this circuit includes a series circuit of a pair of transistors Q ₁ and Q ₂ composed of bipolar transistors, and a pair of capacitors C ₁₀ and C _11.
And a series circuit of a pair of diodes D ₁₀ and D ₁₁ are connected between both ends of the power supply unit 3, and capacitors C ₁₀ and C ₁₁
And a connection point between the diodes D ₁₀ and D ₁₁ are connected in common, and a series connection of a choke L _x and a capacitor C _x is provided between this connection point and the connection point between the transistors Q ₁ and Q _2. has a structure obtained by inserting a resonance circuit composed of the circuit, is connected to the load 2 between both ends of the capacitor C _x. Also, a series circuit of transistors Q ₁ and Q ₂ and diodes D ₁₀ and D ₁₀
It is connected in anti-parallel with the ₁₁ series circuits. That is, a half-bridge type inverter circuit is configured. Here, the transistors Q ₁ and Q ₂ are alternately turned on and off at a high frequency by the control circuit 4.

The power supply unit 3 includes a diode Da having a cathode connected to the output terminal of the diode bridge DB, and a choke La connected in series to the anode of the diode Da.
And capacitor Ca, choke La and capacitor C
The diode Db has a cathode connected to a connection point between the series circuit a and the diode Da, and an anode connected to a connection point between the transistors Q ₁ and Q ₂ .
In this configuration, near the peak value of the pulsating voltage output from the diode bridge DB (referred to as a peak), a high frequency generated at the connection point between the two transistors Q ₁ and Q ₂ is applied to the diode D.
b, the capacitor Ca is charged through the choke La, and in the vicinity of the pulsating voltage of the diode bridge DB near 0 V (referred to as a valley), the electric charge of the capacitor Ca is discharged through the diode Da to supply power to the inverter unit 1. Perform

[0010] Therefore, the voltage waveform of the AC power supply AC in FIG.
9 (a), the input voltage to the inverter unit 1 has an envelope as shown in FIG. 9 (b), and the valley voltage is lower than when a smoothing capacitor is used. It is higher than when no capacitor is used. As a result of the input voltage to the inverter unit 1 changing as described above, the load 2
Envelope of the current supplied to the changes to reflect the input voltage to the inverter unit 1 as shown in FIG. 9 (c). That is,
The supply current to the load 2 fluctuates with a cycle every half cycle of the AC power supply AC.
In the valley of the pulsating voltage output by B, the power supplied from the power supply unit 3 to the inverter unit 1 causes a slight pause in the input current from the AC power supply AC.

As an improvement of the circuit shown in FIG. 8 so that a pause period does not occur in the input current from the AC power supply AC,
Japanese Unexamined Patent Publication No. 5-56659 proposes an input current waveform having no pause during this circuit, but has a drawback that the load current waveform fluctuates greatly in accordance with the cycle of the AC power supply. ing.

[0012]

In the former of the circuits of FIGS. 6 and 8 having the characteristic load current waveform as described above, the input current waveform is a sine wave waveform substantially constant with the AC power supply voltage. However, there is a disadvantage that the rush current at the time of turning on the power is high. In the latter case, the rush current at the time of turning on the power can be reduced, but there is a disadvantage that the input current has a pause. In addition, when the input current waveform is similar to the waveform similar to the waveform of the input voltage, the ripple component of the load current increases. In order to solve the problem with a control circuit, means for varying the oscillation frequency between the valley and the peak of the pulsating waveform obtained by rectifying the AC power supply is required. In this case, there has been a problem that the circuit configuration becomes complicated and the cost becomes expensive. Also by varying the oscillation frequency, it is considered that noise from the power supply unit is increased, there is a disadvantage that its countermeasure circuit are needed. For example, when the load is a discharge lamp, there is a problem that the ripple component of the light output is large, so that it appears as flickering, and the light output is reduced to lower the lamp efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to improve the distortion of the input current and reduce the inrush current at the time of turning on the power by using a simple circuit configuration. It is an object of the present invention to provide a power supply device with reduced load current ripple.

[0014]

According to the first aspect of the present invention, an AC power supply, a diode bridge for rectifying the AC power, and a pulsating current output from the diode bridge are provided. and an inverter section that converts the voltage into an AC high frequency, a power supply device for connecting a load to the output of the inverter section, the one end of the AC power supply da
The first and second capacitors are connected between the anode and the anode of the ion bridge.
Connected in series with each other, and the inverter unit is connected to the die
First and second switches connected between the output terminals of the auto bridge.
Series circuit of a switching element and the first and second switches
Between the connection point of the switching element and the first and second capacitors
Primary choke for resonance choke and feedback transformer between points
And a parallel circuit of the load and the resonance capacitor.
Then, with the load, resonance capacitor and resonance choke
An oscillation circuit, the first and second switching elements
The feedback corresponding to each provided in the feedback transformer
It is turned on and off alternately by the output of the
The diode is provided between both ends of the second switching element.
A first diode in the opposite direction to the output of the bridge;
Connecting a series circuit with a third capacitor;
Through the second diode from the connection point of the switching element of
Then, the high frequency output of the inverter unit outputs the third
A power supply unit with a path for charging the capacitor is provided.
It is characterized by.

According to a second aspect of the present invention, there is provided an AC power supply, a diode bridge for rectifying the AC power, and the diode.
An inverter for converting a pulsating voltage output from the bridge to a high-frequency AC, and a power supply device for connecting a load to an output of the inverter.
Is the series circuit of the first and second diodes and the third and fourth
The diode is connected via a parallel circuit with a series circuit of diodes.
The first and second switches between the output ends of the
Connected to a series circuit of switching elements and the first switch.
The load and the first resonance capacitor are connected in parallel with the switching element.
Sensor parallel circuit, coupling capacitor, and resonance
Circuit with choke for feedback and primary winding of feedback transformer
And the primary winding of the feedback transformer and the resonance
Second and third resonance capacitors in a series circuit with a choke
Are connected in parallel, and the first, second
Connection point of the diode and the second resonance capacitor
A fourth point between the feedback transformer and a connection point with the primary winding;
And the third and fourth diodes are connected.
The connection of the second and third resonance capacitors to the connection point of the
Connect the continuation points and place the first and second switching elements in front.
Return windings corresponding to each provided in the return transformer
It turns on and off alternately with the output of the line, and the diode
The output of the diode bridge is connected between the output terminals of the bridge.
A fourth diode in the opposite direction to the force and a capacitor
Connected in series with the
That a power supply with a path for charging the sensor is provided.
Features.

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

According to the present invention, the power supply unit for smoothing and storing the high-frequency output of the inverter unit and supplying power to one end of the series circuit of the first and second switching elements of the inverter unit is provided. The peak value of the load current waveform is lowered even if the sine waveform has substantially the same phase with respect to the AC power supply voltage, and the peak value of the pulsating voltage of the AC power supply has a substantially constant peak value of the load current waveform at the trough. Load output can be obtained,
In addition, since the high-frequency output of the inverter section is smoothed and stored and supplied to one end of the series circuit of the first and second switching elements of the inverter section as described above, an inrush current flows to the power supply section when the power is turned on. Absent.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention,
Will be described with reference to the drawings. (Basic Example) FIG. 1 shows a circuit of this basic example, this basic example is the series of the switching element Q _10, Q ₁₁ of inverter unit 1 between the output terminals of the diode bridge DB for full-wave rectifying an AC power source AC The circuit and the power supply unit 3 'are connected respectively. Also connected vibration circuit constituted by series resonant circuit consisting of the choke L ₀ and capacitor C ₀ and the load 2 which is the switching element Q ₁₀ of inverter unit 1, the connection point of the capacitor C ₀ and the load 2 or the capacitor C The input terminal of the diode bridge DB is connected via an impedance element Z between ₀ and the choke C ₀ . The switching elements Q ₁₀ and Q ₁₁ of the inverter unit 1 are turned on and off alternately by the control circuit 4. The power supply unit 3 ′ has substantially the same configuration as the power supply unit 3 used in FIG. 8 , but includes a diode Da, a choke Lb,
The difference is that a capacitor Cb having a much smaller capacity than the capacitor Ca composed of an electrolytic capacitor is connected in parallel with the series circuit of the capacitor Ca. Since the capacitor Cb is for regenerative current of the inverter unit 1 and has a small capacity, an inrush current when the power is turned on is very small.

In this basic example , as in the conventional example ( FIG. 8 ), near the peak value of the pulsating voltage output from the diode bridge DB (peak portion a), both switching elements Q ₁₀ and Q
_The high frequency generated at the connection point ₁₁ is connected to the diode D of the power supply 3 '.
b, the capacitor Ca is charged through the choke La by this rectified output , and the diode bridge D
In the vicinity of 0 V of the pulsating voltage of B (valley b), the capacitor C
Power is supplied to the inverter unit 1 by discharging the electric charge of a through the diode Da.

The inverter unit 1 includes switching elements Q ₁₀ ,
The alternate off of Q ₁₁ becomes an AC power source AC voltage and an input current substantially similar in shape shown in FIG. 2 (a), also the AC power supply A
A load current that increases and decreases in the opposite direction to the increase and decrease of the voltage of C flows. The load current waveform is as shown in FIG. 2 (b), while the load current waveform of the power supply unit 3 'is as shown in FIG.
The waveform is as shown in FIG.

Therefore, by combining the two load current waveforms, the peak value of the load current waveform decreases as shown in FIG. 2D, and the voltage obtained by full-wave rectification of the AC power supply AC of FIG. The waveform has peaks at peaks a and valleys b, and a substantially constant load output is obtained. That is, as described in the description of the conventional example, the power supply voltage of the inverter unit 1 is reduced by the power supply unit 3 'at the trough of the pulsating voltage waveform obtained by full-wave rectifying the AC power supply AC as shown in FIG. However, as described in the conventional example, the inverter unit 1 performs the circuit operation such that the load output becomes maximum at the trough of the pulsating voltage waveform obtained by full-wave rectification of the AC power supply AC by the two resonance operations. By the two opposing circuit operations, FIG.
The load current waveform shown in (d) can be obtained.

Since the capacitor Ca of the power supply 3 'is charged at a high frequency of the inverter 1, no rush current flows when the power is turned on. Next, examples of the present invention will be described. Example 1 This examples are those applied to the conventional example of FIG. 6 described above the structure of the basic example, in this embodiment, instead of the electrolytic capacitor C _2, which had been provided in the conventional example of FIG. 6 in, the basic example <br/> similar configuration of the power supply unit 3 'are those used as shown in FIG. 3, also the impedance element Z in the basic example capacitor C ₄ is configured.

Thus, in this embodiment, the input voltage waveform of the inverter unit 1 is as shown in FIG. 9B by the power supply unit 3 '. On the other hand, since the waveform of the load current flowing to the inverter unit 1 as a waveform as shown in FIG. 2 (b), the basic
The combined load current waveform as in the example has a waveform as shown in FIG. Accordingly, as shown in FIG. 4, the input current waveform of the present embodiment becomes a sine waveform (b) having the same phase as the voltage waveform (a) of the AC power supply AC, and the input current distortion is improved.

[0028]

(Embodiment 2) This embodiment is applied to a circuit shown in US Pat. No. 4,949,013, and is replaced with a smoothing capacitor of the circuit.
The basic example and Example 1 similarly to the power source unit 3 'is obtained using, as shown in FIG. In this embodiment, a series circuit of the transistors Q ₁ and Q ₂ of the inverter unit 1 is connected between the output terminals of the diode bridge DB via diodes D ₅ and D ₆ and a filament F ₁ of the discharge lamp LP. . Also the series circuit of the diode D _5, D ₆ are connected a series circuit of a diode D _7, D8 in parallel, between the connection point of the connection point between the transistors Q1, Q ₂ of the diode D _5, D ₆ the resonance capacitor C ₂₂ between the connecting point of the connection point between the transistors Q _1, Q ₂ of the resonance capacitor C _21, and also the diode D _7, D _8, further diode D
_7, the choke L ₁₀ for resonating the resonance capacitor C ₂₃ is provided between the connection point of the connection point between the transistors Q _1, Q ₂ of the D ₈
It is connected via the primary winding of the transformer RK ₁ for feedback.

The resonance circuit section of the inverter section 1 has a series circuit configuration of transistors Q ₁ and Q ₂ , and has a peak of a pulsating voltage output from a coupling capacitor C ₂₀ , a resonance choke L _10, and a diode bridge DB. parts and constituted by a capacitor C ₂₁ to C ₂₃ as a different resonant operation in the valleys. The resistors R ₁₀ and R _{10 are} used for starting the transistor Q _1.
11 , a starter circuit comprising a diac Q ₃ and a capacitor C ₂₄ is provided. Further, the capacitor C ₁ is provided between a connection point of the discharge lamp LP and the transistors Q ₁ and Q _{2 in} a base-emitter circuit of the transistors Q ₁ and Q _{2. 20,} and each other by connecting the feedback winding RK _2, RK ₃ of transformer RK ₁ that has been inserted through the primary winding via the choke L _10, the feedback winding RK
And performs a self-excited oscillation operation by the output of the _2, RK _3.

The discharge lamp LP is the resonance choke L _1, a coupling capacitor C _20, is connected to both ends of the resonance capacitor C ₂₅ to perform a resonant operation by the resonance circuit of the resonance capacitor C _25, generated at both ends It is turned on by the high frequency voltage. Part inverter section 1 of a diode as described above in each unit D ₅ to D _7, since the pulsating voltage obtained by rectifying an AC power source AC output from the diode bridge DB via a capacitor C ₂₁ to C ₂₃ is applied In addition, the resonance operation of the inverter unit 1 is affected by the amplitude of the pulsating voltage obtained by rectifying the AC power supply AC. The amplitude of the pulsating voltage obtained by rectifying the AC power supply AC by the diode bridge DB moves between the peak and the valley, so that the resonance operation changes between the peak and the valley, and flows into the discharge lamp LP. The lamp currents are different, that is, lower at the peak, higher at the valley,
During that time, since it changes in a sine wave form of the AC power supply AC,
The lamp current waveform is similar to the load current shown in FIG.

[0032] In Thus to this embodiment, the ridges a pulsating voltage waveform obtained by rectifying the AC power source AC, the valley b, a resonance capacitor C ₂₁ to C ₂₃ are involved, the result The current waveform of the discharge lamp LP as a load has a waveform as shown in FIG. Further, since the input voltage of the inverter unit 1 by the valley filling power supply unit 3 'is as shown in FIG. 9B, opposing operations at the valley a and the peak b of the AC power supply AC result in FIG. A lamp current waveform as shown in (d) is obtained, the peak value of the lamp current waveform can be suppressed, and a waveform having a low crest factor can be obtained. Then, as shown in FIG. 4, the input current waveform has a sine waveform B having the same phase as the voltage waveform A of the AC power supply AC, and the input current distortion is improved.

[0033]

[0034]

[0035]

According to the present invention, the power supply unit for smoothing and storing the high-frequency output of the inverter unit and supplying power to one end of the series circuit of the first and second switching elements of the inverter unit is provided. The peak value of the load current waveform is lowered even if the sine waveform has substantially the same phase with respect to the AC power supply voltage, and the peak value of the pulsating voltage of the AC power supply has a substantially constant peak value of the load current waveform at the trough. Load output can be obtained,
In addition, since the high-frequency output of the inverter section is smoothed and stored and supplied to one end of the series circuit of the first and second switching elements of the inverter section as described above, an inrush current flows to the power supply section when the power is turned on. There is an effect that it can be realized with a simple circuit configuration.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a basic example of the present invention.

FIG. 2 is a waveform diagram for explaining the operation of the above.

FIG. 3 is a specific circuit diagram of Embodiment 1 of the present invention.

FIG. 4 is a waveform diagram for explaining the operation of the above.

FIG. 5 is a circuit configuration diagram according to a second embodiment of the present invention.

FIG. 6 is a specific circuit diagram of a conventional example.

FIG. 7 is a waveform diagram for explaining the operation of the above .

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

FIG. 9 is a waveform chart for explaining the operation of the above .

[Explanation of symbols]

1 inverter 2 load 3 'power unit 4 the control circuit L ₀ choke C ₀ capacitor La choke Ca, Cb capacitor Da, Db diode Z impedance element Q _10, Q ₁₁ switching elements DB diode bridge AC AC power supply

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-56659 (JP, A) JP-A-6-315272 (JP, A) US Patent 5,313,142 (US, A) US Patent 5,223,767 (US, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H02M 7/48 G05F 1/10

Claims (2)

(57) [Claims] An AC power supply and a die for rectifying the AC power.
And the odd bridge, and an inverter unit for converting the pulsating voltage output from the diode bridge into an AC high frequency, a power supply device for connecting a load to the output of the inverter unit, the diode bridge and one end of the AC power source Negative electrode and
, A series circuit of first and second capacitors is connected, and the inverter unit is connected between output terminals of the diode bridge.
Series circuit of first and second switching elements connected to
And a connection point between the first and second switching elements and
A resonance choke between the connection point of the first and second capacitors
And the load via the primary winding of the feedback transformer.
Connect the parallel circuit of the
A vibration circuit is composed of a capacitor and a choke for resonance.
The first and second switching elements are used as the feedback transformer.
The output of the feedback winding corresponding to each of the
Intended to turnoff, the first, is across the second switching element, wherein
A first die in the opposite direction to the output of the diode bridge
Connecting a series circuit of an ode and a third capacitor;
A second die from a connection point of the second switching element;
Via the high-frequency output of the inverter unit
A power supply unit having a path for charging the third capacitor is provided.
Power supply, characterized in that is. 2. An AC power supply and a die for rectifying the AC power.
In a power supply device including an auto bridge and an inverter unit that converts a pulsating voltage output from the diode bridge into a high-frequency AC, and a load connected to an output of the inverter unit, the inverter unit includes first and second Series of two diodes
Parallel circuit of the path and the series circuit of the third and fourth diodes
Between the output terminals of the diode bridge
Connecting the series circuit of the second switching element
And the load, in parallel with the first switching element.
The first resonance capacitor parallel circuit and the coupling
Capacitor, resonance choke, and feedback transformer
A series circuit with the next winding is connected, and one of the feedback transformers is connected.
The second and third series circuits are connected in series with the secondary winding and the choke for resonance.
And connecting a series circuit of resonance capacitors
The connection point of the first and second diodes and the second
Between the resonance capacitor and the primary winding of the feedback transformer
A fourth resonance capacitor is connected between the connection point and the connection point,
The connection points of the third and fourth diodes are connected to the second and third diodes.
Connecting the connection points of the vibration capacitors to the first and second switches.
Each of the switching elements provided in the feedback transformer
That alternately turn on and off with the output of the feedback winding corresponding to
The diode is connected between the output terminals of the diode bridge.
Fourth diode in the opposite direction to the output of the bridge
And a series circuit with a capacitor to
Power supply with a path to charge the capacitor with frequency output
A power supply device, which is provided .