JPH0586131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a power supply device that drives a load circuit with a voltage obtained by rectifying an AC power supply voltage.

[Background technology]

FIG. 1 is a circuit diagram showing a conventional power supply device.
In the figure, E is an AC power source, and a voltage control device C is connected to this AC power source E. The voltage control device C consists of a voltage control element _Q3 such as a triac and a phase control circuit D such as a relaxation oscillation circuit. A rectifier circuit B consisting of a diode bridge is connected to the output end of the voltage control device, and a load circuit consisting of an inverter circuit A and a load section I is connected to the DC output end of the rectifier circuit B. A specific circuit example of the phase control circuit D is shown in FIG. This circuit consists of a rectifier circuit B′, resistors R ₃ , R ₄ , R ₅ ,
It consists of R ₆ , Zener diode Z, capacitor C ₅ , unijunction transistor (UJT) Q ⁶ , and transformer T ₃ and is generally well known, so a description of its operation will be omitted. 3a to 3c are explanatory diagrams of the operation of the conventional circuit shown in FIG. 1 when the voltage control device C reduces the voltage supplied to the load circuit. Figure a shows the output voltage V′ _E of voltage control device C, and figure b
indicates the current I _S flowing from the AC power source E,
Further, c in the figure shows the current I _la flowing through the load section l. As shown in FIG. 3, it is assumed that the voltage control element Q ₃ of the voltage control device C is controlled by the phase control circuit D so as to be rendered conductive at times t ₁ and t ₂ . As is clear from FIG. 3, in the conventional example, there is a period during which no current flows in the load circuit, especially when the load circuit includes an inverter circuit A as shown in FIG. If the operation becomes intermittent, the inverter oscillation operation becomes unstable, or the inverter circuit A
There was a problem such as noise being generated from the oscillation transformer _T1 that made up the oscillation transformer. In addition, when a discharge lamp is used as the load section l, the current flowing through the discharge lamp I _la
Since there is a pause period between lamps, the luminous efficiency of the lamp decreases, causing problems such as flickering.

FIG. 4 is a circuit diagram showing another conventional example.
The difference from the conventional example in the figure is that a smoothing capacitor C ₀ is connected to the output terminal of the rectifier circuit B. In the circuit of FIG. 4, as shown in FIG. 5, even when the voltage control element _Q3 is non-conducting, the inverter circuit A operates by discharging the smoothing capacitor _C0 . The flowing current has no rest period as shown in c of the same figure. Therefore, problems such as the unstable operation of the inverter circuit A and the generation of noise as in the conventional example shown in Fig. 1 can be solved, and also the problems that occur when a discharge lamp is used as the load section L can be improved. This problem is also improved. However, in the conventional example shown in FIG. 4, a large current flows from the AC power supply E through the voltage control element Q ₃ , the rectifier circuit B, and the capacitor C ₀ at timings t ₁ and t ₂ when the voltage control element Q ₃ conducts. There was a problem that a surge current would flow, and there was a risk that the voltage control element _Q3 would be destroyed due to this surge current. In order to improve this, a circuit for reducing surge voltage is inserted in series with the closed circuit passing through AC power supply E, voltage control element Q ₃ , rectifier circuit B, capacitor C ₀ , rectifier circuit B, and AC power supply E. Since such circuits include impedance elements such as resistors and inductances, switch circuits such as SCRs, etc., there is a problem that the circuit configuration becomes complicated.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a power supply device that can reduce the rush current when the power is turned on and has stable operation. It is.

[Disclosure of the invention]

The configuration of the present invention will be described below with reference to illustrated embodiments. FIG. 6 is a circuit diagram of an embodiment of the present invention.
In Figure 6, E is an AC power supply, and this AC power supply E
Connect voltage control device C to. This voltage control device C consists of a voltage control element _Q3 such as a triac and a phase control circuit D such as a relaxation oscillation circuit. A rectifier circuit B consisting of a diode bridge is connected to the output end of this voltage control device C. These voltage control device C and rectifier circuit B constitute a power supply section, and a transformer T ₂ is connected between the DC output terminals of rectifier circuit B, which are the DC output terminals of the power supply section.
Primary winding n ₁ and one oscillation part of inverter circuit A
Smoothing capacitor C ₂ is connected through A ₁ , and smoothing capacitor C ₁ is connected through secondary winding n ₂ of transformer T ₂ and the other oscillating part A ₂ of inverter circuit A. . A diode _D1 is connected between the smoothing capacitors _C1 and _C2 in a direction opposite to the rectification direction of the rectifier circuit B.
The charge of C ₁ and C ₂ is discharged. The collectors of transistors Q ₁ and Q ₂ in oscillation units A ₁ and A ₂ of inverter circuit A are connected to primary windings n ₁ and n ₂ of oscillation transformer T ₁ , respectively. Feedback windings n ₄ and n ₅ of an oscillation transformer _{T 1 are} connected between the base and emitters of the transistors Q 1 and Q ₂ , respectively, so that the transistors Q ₁ and Q ₂ are turned on and off alternately. When the transistors Q ₁ and Q ₂ are turned on, the iron core of the oscillation transformer T ₁ is alternately excited in opposite directions by the current flowing through the primary windings n ₁ and n ₂ . Note that the resistors R ₁ and R ₂ are bias resistors for starting the transistors Q ₁ and Q ₂ , and the capacitors C ₃ and C ₄ are resonance capacitors.

In the circuit of this embodiment, the transformer T ₂ substantially flattens the current flowing through the transistors Q ₁ and Q ₂ to reduce the switching loss of the transistors Q ₁ and Q ₂ , and when the AC power supply E is turned on, the rectifier circuit B
From, primary winding n ₁ of transformer T ₂ , oscillating transformer
T ₁ primary winding n ₁ , transistor Q ₁ , capacitor
Reduces inrush current flowing into C ₂ and inrush current flowing from rectifier circuit B through capacitor C ₁ , secondary winding n ₂ of transformer T ₂ , primary winding n ₁ of oscillation transformer T ₁ , and transistor Q ₂ It is for the purpose of
Here, the transformer _T2 is not a main requirement constituting the invention of FIG. 6, and the transformer _T2 can be omitted. In this case, the inrush current when the AC power source E is turned on can be reduced by the oscillating parts A ₁ and A ₂ .

In this embodiment, the oscillation section _A1 and the load section l of the inverter circuit A constitute a first load circuit, and the oscillation section _A2 and the load section I constitute a second load circuit. However, the first and second load circuits are not limited to inverter circuits, and may be chopper circuits, converter circuits, or the like. Further, a load may be connected to each of the first and second load circuits, or the outputs may be combined to drive one load as in the embodiment of FIG.

7a to 7d are explanatory diagrams of the operation when the voltage control element _Q3 in the voltage control device C of the embodiment of FIG. 6 is conductive for the entire period. 7a shows the voltage V _E of the AC power source E, and FIG. 7 b shows the current I _S flowing from the AC power source E into the rectifier circuit B. FIG. Figure 7c shows the current I _C1 flowing through the smoothing capacitor _C1 and the current I _C2 flowing through the smoothing capacitor _C2 .
FIG. 7d shows the current flowing through the secondary winding _n3 of the oscillation transformer _T1 and the current flowing through the load section l. As is clear from the above figures, when the voltage V _E of the AC power supply E is high (t ₁ - t ₂ , t ₃ - t ₄ , t ₅ -
At t ₆ ), the smoothing capacitor C ₂ is charged via the oscillator A ₁ of the inverter circuit A, and
The smoothing capacitor _C1 is charged via the oscillation section _A2 of the inverter circuit A. on the other hand,
When voltage V _{E of AC power supply E} is low (t ₂ to _{t 3} , t ₄ to _{t 5} )
, a current I _S flows from the AC power source E to the rectifier circuit B.
does not flow, the charge in the smoothing capacitor _C1 is discharged to the oscillation part _A1 via the diode _D1 , and the charge in the smoothing capacitor _C2 is discharged to the oscillation _{part A2} via the diode D1. be. In this way, in the circuit of Figure 6, the smoothing capacitors C ₁ and C ₂
is charged through the oscillating parts A ₁ and A ₂ of the inverter circuit A, so the period when the current I _S flows from the AC power supply E to the rectifier circuit B is as shown in Fig. 7b.
As shown in FIG. 4, the charging current is considerably longer, and the input power factor is also improved compared to the conventional example shown in FIG. 4, in which the charging current flows only near the peak value of the power supply voltage _VE . Note that the power supply voltage is higher than the smoothing capacitor voltage.
During the period (t ₂ - _{t 3} ) and (t ₄ - _{t 5} ) in which V _E | is lower,
This is when the power supply voltage |V _E | becomes lower than the sum of the voltages of each smoothing capacitor (V _C1 +V _C2 ), or when the power supply voltage |V _E | becomes less than half of the peak value.

8a to 8d are voltage control device C according to the embodiment of FIG. 6.
FIG. 4 is an explanatory diagram of the operation when the voltage supplied to the load circuit is reduced by . FIG. 8a shows the output voltage V' _E of the voltage control device C, and FIGS. 8b to d show waveforms of the same portions as FIGS. 7b to d. In _{FIG .} 8 _{, the} phase control circuit D
Suppose that it is controlled by As is clear from each figure, when the output voltage of the voltage control device C is high ( _t1 to _t2 , _t3 to _t4 , _t5 to _t6 ), the oscillation part _A1 , which is the first load circuit, is The smoothing capacitor _C2 is charged through the oscillator, which is the second load circuit.
The smoothing capacitor _C1 is charged via _A2 . On the other hand, when the output voltage of the voltage control device C is low (t ₂ - _{t 3} , t ₄ - _{t 5} ), the current _IS does not flow from the AC power supply E to the rectifier circuit B, and the charge in the smoothing capacitor C ₁ is The charge is discharged through the diode _D1 to the oscillation section _A1 , which is the first load circuit, and the charge in the smoothing capacitor _C2 is discharged through the diode _D1 to the oscillation section _A2 , which is the second load circuit. be. In this manner, at times t ₁ , t ₃ , and t ₅ when the voltage control element Q ₃ of the voltage control device C is conductive, the smoothing capacitors C ₁ and C ₂ are connected to the oscillation units A ₁ and A ₂ which are load circuits.
Since the capacitors are charged through the smoothing capacitors C ₁ and C ₂ at times t ₁ , t ₃ , and t ₅ , there is no inrush current. (Due to the rectification effect of the diode _D1 , no current flows from the AC power source E through the rectifier circuit B to the capacitor _C1 , diode _D1 , and capacitor _C2 .) Also, the smoothing capacitor
Since there are charges C ₁ and C ₂ , the power supply to the load circuit does not stop as shown in Figure 8d, and
Therefore, the load circuit is stabilized. In addition, especially when an inverter or the like is used as a load circuit, it is possible to eliminate inconveniences such as noise generated by transformers constituting the inverter circuit due to the current suspension period. Furthermore, when a discharge lamp is used as the load, flickering of the luminous flux during dimming can be significantly reduced.

FIG. 9 shows another embodiment of the present invention, which differs from the embodiment in FIG. 6 in that first, a voltage control device C is connected to the output side of the rectifier circuit B to control the DC voltage. It is something. Although a reverse blocking three-terminal thyristor is used as the voltage control element _Q3 , a power transistor may also be used.
Further, in this embodiment, inductance _{L 1 ,}
Connecting L ₂ . Such inductance L ₁ ,
L ₂ substantially flattens the current flowing through the transistors Q ₁ and Q ₂ to reduce the switching loss of the transistors Q ₁ and Q ₂ , and also reduces the rush current flowing into the capacitors C ₁ and C ₂ when the AC power supply E is turned on. It is also intended to reduce the Furthermore, in this embodiment, the feedback windings n ₄ , n ₅ of the oscillation transformer T ₁
, transistor Q ₁ via diodes D ₂ and D ₃ ,
It is connected to the emitter of Q ₂ , and the diode D ₂ ,
Since excessive base current to transistors Q ₁ and Q ₂ can be cut by D ₃ , switching loss can be reduced. In this embodiment, two discharge lamps l ₁ and l ₂ connected in series are used as the load unit l. The capacitor _C5 connected in parallel with the discharge lamp _l1 is for lighting assistance.

FIG. 10 shows still another embodiment of the present invention. In this embodiment, the first and second
The chopper circuits F ₁ and F ₂ are used as load circuits. The chopper circuits F ₁ and F ₂ are transistors
Q ₄ , Q ₅ and on/off control circuit G ₁ , G ₂ , diode
D ₄ , D ₅ , Chiyoke coil L ₃ , L ₄ , and discharge lamp
It consists of l ₁ and l ₂ . The on/off control circuits G ₁ and G ₂ and the voltage control device C detect fluctuations in the voltage and current of the load, for example, and feed back this detected voltage to make the output a constant voltage or constant power (or make the input a constant power). It may also be configured to

〔Effect of the invention〕

The present invention relates to a voltage control device that inputs an AC power supply voltage or a pulsating voltage obtained by rectifying the AC power supply and performs output control through phase control; and a rectifier circuit that rectifies the phase-controlled AC output of the voltage control device; A rectifier circuit that rectifies an AC power source to provide a pulsating voltage to the voltage control device constitutes a power supply section, and a circuit in which a first and a second smoothing capacitor are connected in series to both ends of a diode is connected to the power supply section. connected between the DC output terminals of the diode so that the rectification direction of the diode is opposite to the output polarity of the power supply section,
A first load circuit is connected in parallel with the series circuit of the first smoothing capacitor and the diode, and a second load circuit is connected in parallel with the series circuit of the second smoothing capacitor and the diode. Therefore, the output of the rectifier circuit is charged to the second smoothing capacitor via the first load circuit, and is also charged to the first smoothing capacitor via the second load circuit. This has the effect of significantly improving the input power factor compared to the conventional method of connecting a smoothing capacitor directly to the output of the rectifier circuit, and also reduces the voltage when the voltage value of the AC power supply is low or by using a voltage control device. When the first smoothing capacitor is running, the charged charge of the first smoothing capacitor is supplied to the first load circuit via the diode, and the charged charge of the second smoothing capacitor is supplied to the second load circuit via the diode.
Since the current is supplied to the load circuit, there is no interruption in the current supplied to the load circuit, which has the effect of stabilizing the operation of the load circuit.
Furthermore, the inrush current that flows into the smoothing capacitor when the power is turned on or the switch element of the voltage control device is turned on can be limited by the impedance of the load circuit, which has the effect of preventing excessive current from flowing into the smoothing capacitor. There is.

Note that when a discharge lamp lighting circuit consisting of an inverter oscillator and a discharge lamp is used as a load circuit, dimming can be performed using a voltage control device, and in this case, the inverter oscillates intermittently during dimming. Since the lamp does not stop, flickering of the discharge lamp can be reduced.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional example, Figure 2 is a circuit diagram of the same essential parts as above, Figure 3 is an explanatory diagram of the same operation as above, Figure 4 is a circuit diagram of another conventional example, and Figure 5 is an operation of the same as above. Explanatory diagram,
FIG. 6 is a circuit diagram of one embodiment of the present invention, FIGS. 7 and 8 are explanatory diagrams of the same operation as above, FIG. 9 is a circuit diagram of another embodiment of the present invention, and FIG. 10 is a circuit diagram of another embodiment of the present invention. FIG. 7 is a circuit diagram of still another embodiment. E is an AC power supply, C is a voltage controller, B is a rectifier circuit, C ₁ and C ₂ are capacitors, D ₁ is a diode, A
is an inverter circuit, A ₁ and A ₂ are oscillation sections, and l is a load section.

Claims (1)

[Scope of Claims] 1. A voltage control device that inputs an AC power supply voltage or a pulsating voltage obtained by rectifying the AC power supply and performs output control through phase control, and a rectifier that rectifies the phase-controlled AC output of the voltage control device. a circuit or a rectifier circuit that rectifies the alternating current power supply and provides a pulsating voltage to the voltage control device, forming a power supply section, and a circuit in which a first and a second smoothing capacitor are connected in series to both ends of a diode, respectively, The first diode is connected between the DC output terminals of the power supply unit so that the rectification direction of the diode is opposite to the output polarity of the power supply unit.
A first load circuit is connected in parallel with a series circuit of the smoothing capacitor and the diode, and a second load circuit is connected in parallel with the series circuit of the second smoothing capacitor and the diode. Features a power supply device. 2. The power supply device according to claim 1, wherein the first and second load circuits each include an inverter oscillation section and a load driven by the output of the inverter oscillation section. . 3. The power supply device according to claim 2, wherein the load is a discharge lamp.