JPH06335250A - Power supply device - Google Patents

Abstract

PURPOSE:To provide a power supply device having improved reliability, by reducing its higher harmonics, and by making its switching stable. CONSTITUTION:A resonant inductor L11 for making the resonance with a second capacitor C2 and a charging inductor L12 for making the charging level of a charging capacitor C3 are formed respectively as two independent inductors of each other. Thereby, the voltage when charging the second capacitor C2 and be made sinusoidal, and the charging level of the charging capacitor C3 can be so as to be the voltage not generating the feed shortage of the energy of an inverter circuit 2, and further, the switching of the inverter circuit 2 can be made stable. Also, the spike current of the collector current flowing through a transistor Q1 can be prevented, and thereby, the switching loss and the generation of the noises in the inverter circuit 2 can be lowered.

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 that suppresses harmonic components.

[0002]

2. Description of the Related Art A conventional power supply device will be described with reference to FIG.

In the conventional power supply device shown in FIG. 5, a full-wave rectifier circuit 1 is connected to a commercial AC power supply E. A first capacitor C1 is connected between the output terminals of the full-wave rectifier circuit 1, and a diode D1 is connected in the forward direction on the positive side of the full-wave rectifier circuit 1, and a diode D1 is connected through the diode D1. The second capacitor C2 is connected to the wave rectifier circuit 1. A series circuit including a charging capacitor C3, an inductor L1 and a diode D2 is connected in parallel to the second capacitor C2, and a diode D3 is connected to a connection point of the inductor L1 and the diode D2.

Further, the inverter circuit 2 is connected between both terminals of the second capacitor C2.

In this inverter circuit 2, a series circuit of a primary winding Tr1 of an inverter transformer Tr and a transistor Q1 is connected between both terminals of a second capacitor C2, and
A capacitor C4 is connected in parallel to the next winding Tr1, and a freewheeling diode D4 is connected between the collector and emitter of the transistor Q1.

The secondary winding Tr of the inverter transformer Tr
The filaments FLa and FLb of the discharge lamp FL are connected to 2 via a DC cut capacitor C5. In addition, these filaments FLa and FLb have a starting capacitor.
Connect C6.

Next, the operation of the circuit shown in FIG. 5 will be described.

When the commercial AC power supply E is turned on, the full-wave rectification circuit 1 performs full-wave rectification to charge the first and second charging capacitors C1, C2 and C3.

First, a case where the full-wave rectified pulsating current voltage in the full-wave rectifier circuit 1 is higher than the charging voltage of the charging capacitor C3 will be described.

When the transistor Q1 is turned on, current is supplied to the primary winding Tr1 of the inverter transformer Tr from the first capacitor C1 and a part of the second capacitor C2. Then, the energy from the commercial AC power source E flows in as an input current according to the power supply from the first capacitor C1 and the second capacitor C2. Also, the transistor Q1
When turned on, the charging capacitor depends on the inductor L1.
C3 is charged, and this charging voltage is largely related to the energy supply of the inverter circuit 2. When the pulsating current voltage that is full-wave rectified by the full-wave rectifier circuit 1 is higher than the charging voltage of the charging capacitor C3, the charging capacitor is
The inverter circuit 2 is not discharged from C3.

Next, a case will be described in which the pulsating current voltage that is full-wave rectified by the full-wave rectifying circuit 1 is lower than the charging voltage of the charging capacitor C3.

With respect to the charging voltage of the charging capacitor C3,
If the transistor Q1 turns on when the voltage of the pulsating current that is full-wave rectified by the full-wave rectifier circuit 1 drops, the second capacitor
Current is supplied from C2 to the primary winding Tr1 of the inverter transformer Tr. Since the voltage of the second capacitor C2 is insufficient as the energy required by the inverter circuit 2, the voltage of the second capacitor C2 drops. After that, when the voltage of the second capacitor C2 drops to the voltage of the first capacitor C1, the first capacitor C1 supplies energy to the inverter circuit 2. Further, this operation is continued until the transistor Q1 is turned off.

After supplying energy from the first capacitor C1 to the inverter circuit 2, energy corresponding to the supplied energy is made to flow from the commercial AC power source E as an input current.

On the other hand, the charging voltage of the charging capacitor C3 is
The release of energy is delayed due to the inductance of the inductor L1, and the energy is released immediately before the transistor Q1 is turned on.

After that, when the transistor Q1 is turned off, the charging voltage of the charging capacitor C3 becomes the voltage supply source of the series circuit composed of the inductor L1, the diode D2 and the second capacitor C2. Since the inductor L1 and the second capacitor C2 are set so that resonance can be obtained in a vibrational manner, the charging of the second capacitor C2 is sinusoidal. Then, the charging of the second capacitor C2 is increased until the transistor Q1 of the inverter circuit 2 is turned on next time until the energy is not insufficient.

Further, as the voltage of the first capacitor C1 decreases with respect to the charging voltage of the charging capacitor C3, the amplitude of the inductor L1 and the second capacitor C2 increases and the input current decreases but the current decreases. It flows continuously.

In this way, even in the portion where the pulsating current is close to 0, the harmonic component contained in the input current is reduced by making the input current continuous.

Thus, the inverter circuit 2 controls the switching of the transistor Q1 at high frequency, and the voltage resonated by the inductance of the primary winding Tr1 of the inverter transformer Tr and the charging capacitor C3 is transmitted to the secondary winding Tr2. , Supplied to the discharge lamp FL. Then, the capacitor C5 preheats the filaments FLa and FLb of the discharge lamp FL, and at the same time, the generated voltage of the capacitor C4 is applied to the discharge lamp FL to start and light the discharge lamp FL.

[0019]

As described above, in order to make the input current continuous even in the portion where the pulsating current is close to 0, the charging capacitor C3 can be used even in the portion where the pulsating current is close to 0. It is important that the oscillating voltage of the inductor L1 and the inductor L1 oscillate according to the on / off timing of the transistor Q1.

That is, the oscillation condition of the inductor L1 and the charging capacitor C3 is bad, or the voltage of the second capacitor C2 is not sufficiently increased as shown in FIG. Is insufficient, the inverter circuit 2 causes abnormal oscillation.

In this way, when the inverter circuit 2 causes abnormal oscillation, as shown in FIG.
The collector current Ic flowing through Q1 becomes a rising spike current, which causes a problem that switching loss increases and the amount of noise generated also increases.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply device in which harmonics are reduced, switching is stabilized, and reliability is improved.

[0023]

According to a first aspect of the present invention, there is provided a power supply device comprising: a rectifying means for rectification connected to an AC power source; a first capacitor connected to an output side of the rectification means; A reverse blocking unit connected to the output side of the capacitor in the forward direction with respect to the rectifying unit, a second capacitor connected to the output side of the reverse blocking unit, and a second capacitor connected to the second capacitor of the rectifying unit. A charging capacitor charged with a voltage value lower than the maximum instantaneous voltage; a charging inductor for setting the charging level of the charging capacitor;
A resonance inductor that resonates with the second capacitor;
And a power conversion means having a switching element connected to the capacitor.

According to another aspect of the power supply device of the present invention, the first capacitor connected to the AC power source, the rectifying means connected to the output side of the first capacitor, and the output side of the rectifying means. A second capacitor; a charging capacitor connected to the second capacitor to be charged with a voltage value lower than the maximum instantaneous voltage of the rectifying means; a charging inductor for setting a charging level of the charging capacitor; A resonance inductor that resonates with the second capacitor, and power conversion means having a switching element connected to the second capacitor are provided.

[0025]

According to another aspect of the power supply device of the present invention, the charging inductor for setting the charging level of the charging capacitor serving as the input of the power conversion means and the resonance inductor for setting the resonance with the second capacitor are separately provided. Since it is provided, the inductance or the second which sets the charging level of the charging capacitor
Since it is not necessary to set the inductance to either one of the inductances that set the charge level of the second capacitor, set the charge level of the second capacitor that is the input of the power conversion means to a predetermined value to prevent energy shortage. In addition, the resonance with the second capacitor can be easily set to a predetermined value, the switching loss of the switching element of the power conversion means can be reduced, and the operation of the power conversion means can be stabilized.

According to another aspect of the power supply device of the present invention, the charging inductor for setting the charging level of the charging capacitor which is the input of the power conversion means and the resonance inductor for setting the resonance with the second capacitor are separately provided. Since it is provided, it is not necessary to set the inductance to either the inductance that sets the charging level of the charging capacitor or the inductance that sets the charging level of the second capacitor, so that the second input to the power conversion means is provided. The charge level of the capacitor can be set to a predetermined value to prevent energy shortage, the resonance with the second capacitor can be easily set to a predetermined value, and the switching loss of the switching element of the power conversion means can be reduced to reduce the power consumption. While the operation of the conversion means is stable, the conversion between the first capacitor and the second capacitor It is possible to use a flow means for the reverse blocking circuit configuration is simplified.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the power supply device of the present invention will be described below with reference to the drawings. The parts corresponding to those of the conventional example shown in FIG.

In the conventional power supply device shown in FIG. 1, an input terminal of a full-wave rectifier circuit 1 constituted by a rectifying means such as a diode bridge is connected between output terminals of a commercial AC power source E. A first capacitor C1 is connected between the output terminals of the full-wave rectifier circuit 1, and a diode D1 as a reverse blocking means for preventing reverse current is connected in the forward direction from the positive side of the full-wave rectifier circuit 1. , This diode D1
The second capacitor C2 is connected to the full-wave rectifier circuit 1 via.

In parallel with the second capacitor C2, a charging capacitor C3 charged with a voltage value lower than the maximum instantaneous voltage of the diode D1, a diode D2 for preventing backflow and a second capacitor C2 are connected. A series circuit of resonance inductor L11 that sets resonance is connected, and at the connection point of charging capacitor C3 and diode D2, charging inductor L12 that sets the charging voltage of charging capacitor C3 and diode D3 for backflow prevention are connected. It is connected.

Further, an inverter circuit 2 as a power converting means is connected between both terminals of the second capacitor C2.

The inverter circuit 2 includes a primary winding Tr1 of an inverter transformer Tr and a transistor as a switching element between both terminals of a second capacitor C2.
A series circuit of Q1 is connected, a capacitor C4 is connected in parallel to the primary winding Tr1, and a freewheeling diode D4 is connected between the collector and emitter of the transistor Q1. A self-excited or separately excited oscillator circuit is connected to the base of the transistor Q1.

The secondary winding Tr of the inverter transformer Tr
The filaments FLa and FLb of the discharge lamp FL as a load are connected to 2 through a DC cut capacitor C5. Further, a starting capacitor C6 is connected to these filaments FLa and FLb.

Next, the operation of the circuit shown in FIG. 5 will be described.

When the commercial AC power supply E is turned on, the full-wave rectification circuit 1 performs full-wave rectification to charge the first and second charging capacitors C1, C2 and C3.

First, a case will be described in which the pulsating current voltage that is full-wave rectified by the full-wave rectifier circuit 1 is higher than the charging voltage of the charging capacitor C3.

When the transistor Q1 is turned on, current is supplied to the primary winding Tr1 of the inverter transformer Tr from the first capacitor C1 and a part of the second capacitor C2. Since the combined capacitance of the first capacitor C1 and the second capacitor C2 has sufficient energy to drive the inverter circuit 2, the power from the first capacitor C1 and the second capacitor C2 is reduced. According to the supply, the energy from the commercial AC power supply E flows in as an input current.
Also, when the transistor Q1 is on, the charging inductor
The charging capacitor C3 is charged according to L12. In addition,
When the pulsating current voltage that is full-wave rectified by the full-wave rectifier circuit 1 is higher than the charging voltage of the charging capacitor C3, the charging capacitor C3 is not discharged to the inverter circuit 2. In addition, a diode is connected in series with the inductor L11 for resonance.
Since the diode D2 is connected and the diode D2 blocks the reverse current, the resonance inductor L11 does not affect the charging inductor L12.

Next, a case will be described in which the pulsating current voltage that is full-wave rectified by the full-wave rectifying circuit 1 is lower than the charging voltage of the charging capacitor C3.

For the charging voltage of the charging capacitor C3,
If the transistor Q1 turns on when the voltage of the pulsating current that is full-wave rectified by the full-wave rectifier circuit 1 drops, the second capacitor
Electric power is supplied from C2 to the primary winding Tr1 of the inverter transformer Tr. Since the voltage of the second capacitor C2 is insufficient as the energy required by the inverter circuit 2, the voltage of the second capacitor C2 drops. After that, when the voltage of the second capacitor C2 drops to the voltage of the first capacitor C1, the first capacitor C1 supplies energy to the inverter circuit 2. Further, this operation is continued until the transistor Q1 is turned off.

On the other hand, the charging voltage of the charging capacitor C3 is
Energy is delayed due to the inductance of the charging inductor L12, and energy is discharged immediately before the transistor Q1 is turned on.

After that, when the transistor Q1 is turned off, the charging voltage of the charging capacitor C3 changes to the resonance inductor L11.
, The diode D2 and the second capacitor C2 serve as a voltage supply source for a series circuit. Resonance inductor L1
The constants of the first and second capacitors C2 are set so that resonance can be obtained in a vibrational manner, so the second capacitor C2
The charging of C2 is sinusoidal. Then, the charging of the second capacitor C2 is increased until the transistor Q1 of the inverter circuit 2 is turned on next time until the energy is not insufficient.

Further, as the voltage of the first capacitor C1 decreases with respect to the charging voltage of the charging capacitor C3, the amplitude of the resonance inductor L11 and the second capacitor C2 increases, and the input current decreases. The current flows continuously.

In this way, even in the portion where the pulsating current is close to 0, the harmonic component contained in the input current is reduced by making the input current continuous.

Then, in this way, the inverter circuit 2
Switches the transistor Q1 at high frequency, and the voltage resonated by the inductance of the primary winding Tr1 of the inverter transformer Tr and the charging capacitor C3 is transmitted to the secondary winding Tr2 and supplied to the discharge lamp FL. Then, the capacitor C5 preheats the filaments FLa and FLb of the discharge lamp FL, and at the same time, the generated voltage of the capacitor C4 is applied to the discharge lamp FL to start and light the discharge lamp FL.

According to the above embodiment, the second capacitor C2
Resonance inductor L11 that sets resonance with and charging inductor L1 that sets the charging level of charging capacitor C3
Since 2 and 2 are configured by separate inductors, the voltage when charging the second capacitor C2 can be made a sine wave, and as shown in FIG.
Since the charging level of C3 can be set to a voltage at which the inverter circuit 2 does not have insufficient energy supply, switching of the inverter circuit 2 can be stabilized, as shown in FIG. Therefore, the spike-shaped current of the collector current Ic flowing through the transistor Q1 can be prevented, the switching loss can be reduced, and the amount of noise generated can be reduced.

Another embodiment will be described with reference to FIG.

The embodiment shown in FIG. 4 corresponds to the embodiment shown in FIG. 1 in which the full-wave rectifier circuit 1 is connected between the first capacitor C1 and the second capacitor C2.

In this way, if the full-wave rectifier circuit 1 is connected between the first capacitor C1 and the second capacitor C2, the reverse current blocking diode D1 is not required, and the circuit structure is simplified.

[0048]

According to the power supply device of the first aspect, the resonance inductor for setting the resonance between the charging inductor for setting the charging level of the charging capacitor serving as the input of the power conversion means and the second capacitor. Since and are provided separately,
Since it is not necessary to set the inductance to either the inductance that sets the charging level of the charging capacitor or the inductance that sets the charging level of the second capacitor, charging of the second capacitor that is the input of the power conversion means. The level can be set to a predetermined value to prevent energy shortage, the resonance with the second capacitor can be easily set to a predetermined value, the switching loss of the switching element of the power conversion means can be reduced, and the power conversion means Operation can be stabilized.

According to another aspect of the power supply device of the present invention, the charging inductor for setting the charging level of the charging capacitor serving as the input of the power conversion means and the resonance inductor for setting the resonance with the second capacitor are separately provided. Since it is provided, it is not necessary to set the inductance to either the inductance that sets the charging level of the charging capacitor or the inductance that sets the charging level of the second capacitor, so that the second input to the power conversion means is provided. The charge level of the capacitor can be set to a predetermined value to prevent energy shortage, the resonance with the second capacitor can be easily set to a predetermined value, and the switching loss of the switching element of the power conversion means can be reduced to reduce the power consumption. While the operation of the conversion means is stable, the conversion between the first capacitor and the second capacitor It is possible to use a flow means for the reverse blocking, it can be a circuit configuration simple.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a power supply device of the present invention.

FIG. 2 is a waveform diagram showing a voltage of a second capacitor C2 of the above.

FIG. 3 is a waveform diagram showing a collector, an emitter voltage and a collector current of the same transistor Q1.

FIG. 4 is a circuit diagram showing a power supply device of another embodiment.

FIG. 5 is a circuit diagram showing a conventional power supply device.

FIG. 6 is a waveform diagram showing a voltage of a second capacitor C2 of the above.

FIG. 7 is a waveform diagram showing a collector, an emitter voltage, and a collector current of the same transistor Q1.

[Explanation of symbols]

 1 Full-wave rectification circuit as rectification means 2 Inverter circuit as power conversion means C1 1st capacitor C2 2nd capacitor C3 Charging capacitor D1 Diode as reverse blocking means E Commercial AC power supply L11 Resonance inductor L12 Charging inductor Q1 Transistor as switching element

Claims (2)

[Claims] 1. A rectifying means for rectifying, which is connected to an AC power source, a first capacitor connected to an output side of the rectifying means, and a rectifying means connected to an output side of the first capacitor and connected to the rectifying means. Direction reverse blocking means, a second capacitor connected to the output side of the reverse blocking means, and a charging capacitor connected to the second capacitor and charged at a voltage value lower than the maximum instantaneous voltage of the rectifying means. A charging inductor that sets a charging level of the charging capacitor; a resonance inductor that resonates with the second capacitor; and a power conversion unit that is connected to the second capacitor and has a switching element. Power supply device characterized by. 2. A first capacitor connected to an AC power source, a rectifying means connected to an output side of the first capacitor, a second capacitor connected to an output side of the rectifying means, A charging capacitor that is connected to a second capacitor and is charged with a voltage value lower than the maximum instantaneous voltage of the rectifying means, a charging inductor that sets a charging level of the charging capacitor, and a resonance with the second capacitor. A power supply device comprising: a resonance inductor; and a power conversion unit having a switching element connected to the second capacitor.