JP3326647B2 - Power factor improving rectifier circuit - 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 factor improving rectifier circuit provided, for example, for improving a power factor of a power supply circuit.
It is suitable for application to a so-called wide-range power supply circuit capable of accepting AC power supply input up to the V system.

[0002]

2. Description of the Related Art In a power supply circuit, for example, a so-called world wide power supply circuit which can widely cope with a 100V system AC power input to a 200V system AC power input has become widespread. For example, the operation of the rectifying / smoothing circuit section is switched between the case where the AC power input is 100 V system and the case where the AC power input is 200 V system. Is a 200V system, a normal rectifying / smoothing operation is executed, and a predetermined DC voltage can be obtained regardless of fluctuations in the AC input voltage, for example, by supplying power to a power supply circuit unit at the subsequent stage. Are known.

Further, a power factor improving rectifier circuit capable of improving a power factor at the time of rectifying and smoothing is provided for a power supply circuit. As such a power factor improving rectifier circuit, for example, a choke input system in which a power choke coil is inserted into an AC power supply line to improve a power factor is known.

FIG. 7 is a circuit diagram showing an example of a power supply circuit in which a power factor improving rectifier circuit of a choke input type is provided for the above-mentioned world wide power supply circuit. In FIG. A power supply is shown, and both poles of the AC power supply 1 are connected to windings of the line filter transformer 2 respectively. Ci inserted between the positive electrode line and the negative electrode line at the subsequent stage of the line filter transformer 2 indicates an across capacitor, and forms a low-pass filter together with the line filter transformer 2. PCC-11 inserted between the line filter transformer 2 and the input terminal (connection point of the diodes D ₁ and D ₃ ) of the line filter transformer 2 and the rectifier bridge circuit 3 in the positive line indicates a power choke coil, as shown in the figure. consisting of two winding N _11. That is, in the power supply circuit of this figure, the power choke coil PCC-1
By conduction angle of the current flowing through the AC input by the action of the inductance L _N11 having a first winding N ₁₁ is enlarged, so that the power factor is performed. Reference numeral 3 denotes a rectifying bridge circuit composed of diodes D ₁ , D ₂ , D ₃ , and D _4. Here, the input voltage subjected to full-wave rectification is output to the line 4. Then, the voltage obtained on the line 4 is smoothed by the smoothing capacitors C ₁ and C ₂ to be a DC voltage Ei, which is supplied to a constant power circuit such as a switching power circuit (not shown) at the subsequent stage.

Further, SW ₁ indicated by a broken line is a switch for switching the voltage doubler rectification smoothing operation and normal rectification smoothing operation, the switch SW ₁ is a built-in triac T ₁ shown in FIG example as a switching element, in addition to being a hybrid IC formed by a built-in on / off control circuit for the triac T _1. In this case, the triac T ₁ of the switch SW ₁ is connected between the connection point of the smoothing capacitors C ₁ and C ₂ and the connection end of the rectification bridge circuit 3 (the connection point of the diodes D ₂ and D ₄ ) as shown in the figure. It is provided so that it may be inserted into. R ₁ is a resistor,
C _{3 to} C ₆ denote capacitors and D ₅ denotes a diode, each of which is an external component of the switch SW ₁ . And in these external components, the detection voltage V _D obtained by rectifying smoothing the AC input voltage by the rectification circuit composed of a capacitor C ₃ and the diode D ₅ is obtained. And the switch SW
In ₁ based on the detection voltage V _D, for example, the AC power supply 1
Is controlled to be turned on when the voltage of 150 V or less is supplied and turned on, and turned off and turned off when the voltage of 150 V or more is supplied.
That is, in this case, the switch SW ₁ when the AC power supply 1 is a so-called 100V system is turned on, the AC power supply 1
Is turned off when is a so-called 200V system. The resistance R ₁ is other external components, a capacitor C ₄ -C _6, a protective circuit provided for noise or the like of a surge current and a gate signal of the TRIAC T ₁ of the at on / off triac T ₁ Is formed.

The operation when a 100 V AC voltage is supplied as the AC power supply 1 in the circuit configuration shown in FIG. 7 will be described. In this case, a state capable conducting switch SW ₁ is turned on as described above. The current during the period when the AC input voltage is positive is: AC power supply 1 → winding 2a of line filter transformer LFT → power choke coil PCC-11 → diode D ₃ → smoothing capacitor C ₁ → switch SW ₁ (triac T ₁ )
The current flows through the path from the winding 2b of the line filter transformer LFT to the AC power supply 1. On the other hand, during the period when the AC input voltage is negative, the current is from the AC power supply 1 → the winding 2b of the line filter transformer LFT → the switch SW ₁ → the smoothing capacitor C
₂ → diode D ₁ → power choke coil PCC-1
1 → the winding 2a of the line filter transformer LFT → the AC power supply 1.

That is, in this case, the smoothing capacitors C ₁ ,
Due to the charging of C ₂ during the positive period and the negative period, the voltage Ei is 200 times, which is almost twice the input voltage of the AC power supply 1.
The voltage doubler rectification smoothing operation for obtaining the voltage of the V system is performed.

On the other hand, an AC voltage of 200V system as the AC power supply 1 is when it is supplied, the switch SW ₁ is turned off. In this case, the current during the period when the AC input voltage is positive is: AC power supply 1 → winding 2a of line filter transformer LFT → power choke coil PCC-11.
→ Diode D ₃ → Smoothing capacitor C ₁ → Smoothing capacitor C ₂ → Diode D ₂ → Line filter transformer LF
The current flows through the path from the T winding 2b to the AC power supply 1.
When the AC input voltage is negative, the current is
Flowing in the winding 2b → the diode D ₄ → smoothing path of the capacitor C ₁ → smoothing capacitor C ₂ → diode D ₁ → power choke coil PCC-11 → of the line filter transformer LFT winding 2a → the AC power supply 1 of the line filter transformers LFT . That is, in this case, the bridge rectifier circuit 2
Rectification and normal rectification and smoothing operation by the series capacitors C ₁ and C ₂ are executed to respond to the input voltage.
A V-system DC voltage Ei is obtained.

[0009] By switched this way the switch SW ₁ and the switch, the AC power input to the voltage doubler rectification smoothing operation in case of 100V system, whereas, AC normal full-wave rectification and smoothing when the power input is 200V system By operating, a power supply circuit corresponding to a wide-range AC input voltage is configured.

[0010]

By the way, in the configuration shown in FIG. 7, the power factor is improved to about 0.6 to 0.75 under the condition that the load power is constant (about 200 W). If a, since the conduction angle of the alternating current decreases as the AC power input is increased, in practice the inductance L _N11 winding N ₁₁ of the power choke coil PCC-11 is, if the AC power input of 100V system For example, about 6 mH is required, and when the AC power input is a 200 V system, about 30 mH is required. The peak of the current flowing in the winding N ₁₁ when the AC power input 1
In the case of the 00V system, the current is up to about 8A, and in the case of the 200V system, the current flowing through the inductance L _N11 is about 3.5A. Therefore, if the inductance L _N11 is that using a winding N ₁₁ of 6mH as a power choke coil PCC-11, a force of about 0.75 in the case of the AC power input 100V system as shown in dashed line in FIG. 8 Although the power factor is guaranteed, when the AC power input rises to 230 V, the power factor drops to about 0.5, which is lower than the target value. Therefore, this inductance value L _N11 is 6 m
H is not appropriate.

Also, a power choke coil PCC-11
As if the inductance L _N11 was used winding N ₁₁ of 30 mH, as shown in solid line in FIG. 8, can be AC power input to ensure 0.75 or more power factor even at 100V and at 230V Becomes However, the inductance L _N11 of the power choke coil PCC-11 and 30 mH, and in order to respond to the DC current when the AC input voltage of 100V, for example by using a urethane-rays of a large cross-sectional area as the winding N ₁₁ wound For example, it is necessary to reduce the DC resistance, and as a result, the power choke coil PCC-11 increases in size and weight. As described above, if it is attempted to improve the power factor corresponding to a wide-range AC input voltage by the circuit configuration shown in FIG. 7, the AC input voltage 1 can be reduced by one large power choke coil.
Since a large current and small inductance at the time of 00V and a small current and large inductance at the time of AC input voltage must be realized, the weight and cost are increased.

Therefore, for example, as shown in the circuit diagram of FIG. 9, a power factor improving rectifier circuit that actually corresponds to a wide-range AC input voltage using two power choke coils PCC-1 and PCC-2. It is contemplated to make up.
In this figure, the same parts as those in FIG. In this figure, the connection point on the negative side of the bridge rectifier circuit 3 and the power choke coil PCC-1
SW ₁ which is inserted between the end of a switch for switching the voltage doubler rectification smoothing operation and normal rectification smoothing operation, in the same manner as shown in FIG. 7 above, the capacitor C ₃
And as the detection voltage rectified AC input voltage by a diode D _5, the triac T ₁ is turned on when, for example, the AC input voltage is detected to be 150V or less, 1
When it is detected that the voltage is 50 V or more, it is turned off. Also, the switch SW ₁ and the smoothing capacitor C _1, PCC-1, which is inserted between the C ₂ connection point represents the power choke coil is provided for power factor correction when the AC input voltage 100 V, the winding The inductance L _{N1 of} N ₁ is, for example, 6 mH.

Further, SW ₂ connected in parallel to both ends of the power choke coil PCC-2 represents a switch provided in order to perform the bypass on / off of the power choke coil PCC-2, the switch SW ₁ Similarly, and it is configured as a hybrid IC having a built-in triac T ₂ of the as a switching element. Also in the switch SW _2, the detection voltage a voltage obtained by rectifying smoothing the AC input voltage by the diode D ₁₅ and the capacitor C ₁₃ is external components, triac if the detected voltage corresponds to the example 150V or less T ₂ is turned on, and is controlled to be turned off when it corresponds to 150 V or more. The resistance R _11, capacitors C ₁₄ ~
C ₁₆ is an external component for preventing surge current and noise of a gate signal. The PCC-terminal inserted between the winding 2a of the line filter transformer 2 and the input terminal of the bridge rectifier circuit 3 on the positive line side on the positive line side.
Reference numeral ₂ denotes a power choke coil for ac power voltage improvement of 200 V system. In this power choke coil PCC-2, the inductance L _N2 of the winding N ₂ is set to, for example, 30 mH.

The power supply circuit provided with the power factor improving rectifier circuit having the configuration shown in FIG. 9 operates as follows. First,
When the AC input voltage is 100V system, it turned the switch SW ₁ and the switch SW ₂ is are both turned on and, as described above. In this state, the current during the period in which the AC input voltage is positive is: AC power supply 1 → winding 2a of line filter transformer LFT → switch SW ₂ → diode D ₃
→ Smoothing capacitor C ₁ → Power choke coil PCC-
1 → switch SW ₁ → winding 2b of line filter transformer LFT → AC power supply 1 On the other hand, during the period when the AC input voltage is negative, the current is from the AC power supply 1 → the winding 2b of the line filter transformer LFT → the switch SW ₁ → the power choke coil PCC-1 → the smoothing capacitor C ₂ → the diode D ₁ → the switch SW ₂ → Line filter transformer L
It flows on the path from the FT winding 2a to the AC power supply 1. That is,
Although the voltage doubler rectification smoothing operation by the above current path is performed when the AC input voltage is 100V system, the power choke coil PCC-2 by SW ₂ is turned on in the current path is to be passed Become. On the other hand, so that the alternating current flows as described above in the power choke coil PCC-1, the inductance L _N1 of windings N ₁ of the power choke coil PCC-1 is for example 6
Since it is set to mH, a power factor improvement suitable for a condition of a large current and a small inductance in an AC input voltage 100 V system is performed.

Next, when the AC input voltage is a 200 V system, both the switch SW ₁ and the switch SW ₂ are turned off and become non-conductive. Thus, the route to pass the power choke coil PCC-2 via the switch SW ₂ is cut off and also, the path of the power choke coil PCC-1 becomes opened by SW _1. Therefore, in this state, the current during the period in which the AC input voltage is positive is: AC power supply 1 → winding 2a of line filter transformer LFT → power choke coil PCC-2 → diode D ₃ → smoothing capacitor C ₁ → smoothing capacitor C ₂ → The current flows through a path from the diode D ₂ → the winding 2b of the line filter transformer LFT → the AC power supply 1. In addition, during a period when the AC input voltage is negative, the current flows from the AC power supply 1 to the winding 2 of the line filter transformer LFT.
b → Diode D ₄ → Smoothing capacitor C ₁ → Smoothing capacitor C ₂ → Diode D ₁ → Power choke coil PC
C-2 → the winding 2a of the line filter transformer LFT → the AC power supply 1.

That is, when the AC input voltage is a 200 V system, the rectification by the bridge rectification circuit 2 and the capacitor C
_1, C ₂ smooth operation due is the DC voltage Ei in response to a row that the input voltage is obtained, a current flowing in the power choke coil PCC-2 is in the current path when the. Since the inductance L _N1 of the winding N ₁ of the power choke coil PCC-2 is, for example, 30 mH, it is possible to obtain a small current and large inductance which is a condition for improving the power factor when the AC input voltage is 200 V. Become. Thus, in the case of the AC input voltage 100 V system,
In the case of the 00V system, two types of power choke coils adapted to the respective conditions are provided, and by switching _two switches SW ₁ and SW ₂ , switching of rectifying and smoothing operation according to the AC input voltage and power choke coil Is performed, the rectifier circuit can improve the power factor in response to a wide-range AC input voltage.

However, in the configuration described above,
ON / OFF-controlled two by switches SW ₁ and the switch SW ₂ is required by the AC input voltage. As described above, since these switches are configured by the hybrid IC, the occupied area on the board is considerable, and in addition to the relatively large number of external components required as shown in the figure, It is very difficult to increase the number of parts and to reduce the size of the substrate accompanying the increase in the number of parts, and there is a problem that the cost is high. Further, each switch SW ₁ ,
For on-voltage exists about 1.5V in triac T _1, T _2, which is built in the SW _2, for example, the power loss of the switch SW _1, SW ₂ becomes approximately 3W combined, the switch SW _1, SW ₂ The fever also cannot be ignored. For this reason, it becomes necessary to provide a heat radiating plate, so that the size of the substrate and the like cannot be avoided, and the rectification efficiency also decreases.

[0018]

SUMMARY OF THE INVENTION In view of the above problems, the power factor improving rectifier circuit of the present invention is designed to appropriately perform power factor improvement by a choke input method corresponding to a wide range of AC input voltage. In doing so, it is an object of the present invention to obtain a power factor improving rectifier circuit in which the size of the substrate is reduced, the cost is reduced, the power loss is reduced, and the like.

Therefore, a pair of AC voltage input terminals and a pair of
DC output terminals, and is connected between a pair of AC voltage input terminals.
AC voltage from the power supply is applied, and a pair of DC output terminals
A diode bridge that outputs DC output voltage from one of the
And a pair of rectifier circuits and a diode bridge rectifier circuit.
A current connected between one of the
1 choke coil and diode bridge rectifier
DC output voltage is supplied from one of the pair of DC output terminals.
Series circuit of a first capacitor and a second capacitor
And the connection point between the first capacitor and the second capacitor and the
1 is provided between the choke coil and the AC power supply side,
Has less inductance than the first choke coil
And a series circuit of a second choke coil and a switch.
Detects the magnitude of the AC voltage from the
When the magnitude of the AC voltage exceeds a predetermined value,
Switch off, and the magnitude of the AC voltage from the AC power
Detection of turning on the switch when it becomes less than the specified value
Circuit and the magnitude of the AC voltage from the AC power supply
Is greater than or equal to a predetermined value, the switch is turned off,
Diode bridge rectifier circuit and first and second capacitors
Power supply to perform full-wave rectification and smoothing operation.
These currents flow through the first choke coil,
If the magnitude of the AC voltage from the
Switch on, diode bridge rectification
Voltage doubler rectification smoothing operation for the circuit and the first and second capacitors
And the current from the AC power supply
And a power factor improving rectifier circuit configured to flow through the work coil .

Further, a pair of AC voltage input terminals and a pair of
It has a current output terminal and an AC
AC voltage from the power source is applied, and one of a pair of DC output terminals
Diode bridge that outputs DC output voltage from
Current circuit and a pair of AC power
Intermediate terminal connected between one of the voltage input terminals and the AC power supply.
A choke coil having a
DC from one of the pair of DC output terminals of the ridge rectifier circuit
A first capacitor and a second capacitor to which an output voltage is supplied.
Series circuit with a capacitor, a first capacitor and a second capacitor.
Between the sensor connection point and the choke coil middle tap output terminal.
Switch between the power supply and the AC power supply.
Of the AC voltage from the AC power supply.
If the pressure exceeds the specified value, turn off the switch.
And the magnitude of the AC voltage from the AC power supply is less than the specified value
And a detection circuit that turns on the switch when
The magnitude of the AC voltage from the AC power supply is
If it is above, turn off the switch and turn on the diode
Full-wave rectification on bridge rectifier circuit and first and second capacitors
Current from the AC power supply
AC current from an AC power supply
If the voltage is less than the specified value,
When turned on, the diode bridge rectifier and the first and
The second capacitor performs the double voltage rectification smoothing operation.
The current from the AC power supply
And a power factor improving rectifier circuit configured to flow from the output terminal .

[0021]

According to the above construction, a power choke coil having an inductance capable of improving a power factor in accordance with an AC input voltage is provided by turning on / off a switch for switching between a normal rectifying / smoothing operation and a voltage doubler rectifying / smoothing operation. It becomes possible to select. The power choke coil is connected to the first winding and the second winding.
If a configuration is adopted in which the windings are connected in series and an inductance capable of improving the power factor is selected according to the AC input voltage, only one power choke coil should be provided in the circuit. be able to.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power factor improving rectifier circuit according to the present invention will be described below with reference to FIGS. 1, 2, 3 and 6. FIG. 1 is a circuit diagram showing a power supply circuit including a power factor improving rectifier circuit according to the present embodiment. The same parts as those in FIG. 9 described above are denoted by the same reference numerals, and description thereof will be omitted. In addition, also in this embodiment, the power choke coil PCC-1 is designed to cope with the power factor improvement when the AC input voltage is a 100 V system.
For example, the power choke coil PCC-2 has, for example, a small current and a large inductance so as to correspond to a power factor improvement when the AC input voltage is a 200 V system. .

FIGS. 6A and 6B show examples of the structures of the power choke coils PCC-1 and PCC-2, respectively. The power choke coil PCC-1 is shown in FIG.
Wound winding N ₁ of the thick line for large current as in FIG respect EE type core 10 by for example a silicon steel plate or the like as shown in (a) (are stacked in this case) structure And
The power choke coil PCC-2 is also shown in FIG.
(B) in respect EE type core 10 of laminated silicon steel plates or the like as shown is a structure formed by winding a winding N ₂ of the thin line for small current as in FIG. The switch SW ₁ in this embodiment, there is switching the voltage doubler rectification smoothing operation and normal rectification smoothing operation in the same manner as described in FIG. 9 is configured as a hybrid IC, for example, the AC input voltage 1
When the voltage is 50 V or less, the conduction of the triac T ₁ is turned on,
It is turned off when the voltage is 150 V or more.

In the power factor improving rectifier circuit of this embodiment, the power choke coil PCC-2 is connected to the winding 2b of the line filter transformer 2 and the bridge rectifier circuit 3 on the negative line of the AC power supply as shown in FIG. It is inserted into the between the input (connection point of the diode D ₂ and D _4). The switch SW ₁ has one end connected to the power choke coil PCC-1 side, the other end a power choke coil PCC-2 and line filter transformer second winding 2b at the negative side of the line of the AC power source Is connected to the connection point with

Next, the operation of the power supply circuit having the above configuration will be described with reference to the equivalent circuit diagram of FIG. 2 and the waveform diagram of FIG. FIG. 2A equivalently shows the operation when the AC input voltage is 100 V (in this case, 150 V or less) in the power supply circuit shown in FIG. 1, and FIG. The operation in the case of 200 system (150 V or more) is equivalently shown. 3A shows the waveform of the _AC input voltage VAC, and FIGS. 3B to 3E show the AC input current I _AC when the AC input voltage is 150 V or less.
Rectified and smoothed voltage Vi, the voltage across the smoothing capacitor C ₁ V
_C1, shows the waveform of the voltage V _C2 across the smoothing capacitor C _2, also FIG. 3 (f) ~ (h) the AC input voltage is 15
AC input current I _{AC at} 0 V or more, rectified smoothed voltage V
i, waveforms of a voltage V _C1 across the smoothing capacitor C ₁ and a voltage V _C2 across the smoothing capacitor C ₂ . However, FIG. 3 shows a waveform when the load is constant.

In the case of a 100 V system in which the AC input voltage is 150 V or less, the triac T ₁ of the switch SW ₁ is turned on as shown in FIG. In this state, in the positive period of the AC input voltage (periods 0 to π and 2π to 3π in FIG. 3A), the current flows as indicated by the solid arrow in FIG. . That is, AC power supply 1 → diode D ₃
→ Smoothing capacitor C ₁ → Power choke coil PCC-
1 → triac T ₁ → in the path of the AC power supply 1 is formed, so that the charging current flows with respect to the smoothing capacitor C _1. In addition, the current when the AC input voltage is negative, such as the period indicated by π to 2π in FIG. 3A, is changed from the AC power source 1 to the triac T ₁ → as shown by the broken arrow in FIG.
Power choke coil PCC-1 → smoothing capacitor C
₂ → Diode D ₁ → AC power supply 1 path. That is, in this case a charge operation to the smoothing capacitor C _2.

Accordingly, in this case, the voltage V _C1 across the smoothing capacitor C ₁ has a waveform as shown by the solid line in FIG. _{3D, and} the voltage V _C2 across the smoothing capacitor C ₂ is as shown in FIG. The waveform shown by the broken line in (e) is obtained. In this manner, when the AC input voltage is a 100 V system, the voltage doubler rectification smoothing operation is performed, and a rectified smoothed voltage Vi as shown in FIG. 3C is obtained. Also, at this time, by allowing the current to flow through the power choke coil PCC-1 having an inductance of, for example, about 6 mH in the AC path, for example, the conduction angle of the _AC input voltage I _AC is enlarged (FIG. 3B). The power factor improvement (shown in the τ period) will be performed.

It should be noted in this case, although the power choke coil PCC-2 as shown in FIG. 2 (a) is in a state of being inserted between the AC power source 1 and the diode D _4, a power choke coil inductance 6mH Power choke coil PC with PCM-1 and inductance of 30mH
When comparing the AC impedance of C-2, the power choke coil PCC-2 is much larger,
Also as can be seen from FIG. 3 (a) (d) ( e), in the first half the AC input voltage is in the negative half cycle, (the voltage across the smoothing capacitor _{C 1) V C1> V C2} ( the smoothing capacitor C ₂ since a voltage across), the charging current does not flow into the smoothing capacitor C ₁ through the period power choke coil PCC-2. That is, in this case, the circuit of the power choke coil PCC-2 can be regarded as open.

Next, in the case of a 200 V system in which the AC input voltage is 150 V or more, the triac T ₁ of the switch SW ₁ is turned off as shown in FIG. Thereby, the smoothing capacitors C ₁ and C ₂
Is disconnected from the negative line of the AC input power supply, and the power choke coil PCC
Switch SW ₁ side of the terminal of -1 is open. In this state, 0 ac input voltage V _AC is shown in FIG. 3 (a)
In a positive period such as the period of π, 2π to 3π, the current flows as shown by a solid arrow in FIG. In other words, the smoothing capacitors C ₁ and C ₂ which flow through the path of AC power supply 1 → diode D ₃ → smoothing capacitor C ₁ → smoothing capacitor C ₂ → diode D ₂ → power choke coil PCC-2 → AC power supply 1 and are connected in series Charging operation. In addition, the AC input voltage V _AC in FIG. 3
In the negative period as shown in the π to 2π period of (a), the current is changed from the AC power source 1 to the dashed arrow in FIG.
Power choke coil PCC-2 → diode D ₄ → smoothing capacitor C ₁ → smoothing capacitor C ₂ → diode D ₁
→ flows in a path of the AC power source 1, AC input voltage V _AC is similar to the positive period, the charging operation with respect to the smoothing capacitor C ₁ and C ₂ connected in series. Therefore, the voltage V _C1 across the smoothing capacitors C ₁ and C ₂ in this case,
Both V _C2 are as shown in FIG.
In this manner, when the AC input voltage is of the 200 V system, the rectification and smoothing operation is performed with the action of the smoothing capacitors C ₁ and C ₂ connected in series, so that the rectification and smoothing voltage Vi substantially corresponding to the AC input voltage. (FIG. 3 (g)) is obtained. At this time, for example, the conduction angle of the _AC input current I _AC is reduced by setting the inductance of the power choke coil PCC-2 through which the AC current flows to about 30 mH, as shown in FIG.
The power factor is extended to the period τ shown in FIG.

As described above, the power factor improving rectifier circuit of the present embodiment performs the double voltage rectifying and smoothing operation when the AC power input is 100 V, and performs the normal rectifying and smoothing operation when the AC power input is 200 V. against switchable power circuit so as to, when improve power factor by choke input, the switch SW ₁ is to flow an AC current to the power choke coil PCC-1 in the case of the on for this operation switching When the power supply is off, the AC current flows through the power choke coil PCC-2. Thus, the power factor correction in accordance with the switch SW ₂ AC input voltage is not necessarily provided for performing bypass control of the power choke coil PCC-2 is implemented as shown for example in FIG. As described above, the switch SW ₁ or SW ₂ is configured by a hybrid IC, which in addition to components with various outside is required to be mounted on the substrate, resulting heat generation due to the power loss. Therefore, in the present embodiment, since such a hybrid IC can be provided as a single set, the number of components to be added is reduced, and a heat radiating plate is required to reduce the heat generation amount as compared with the case of two sets. Is also gone.

Next, another embodiment of the present invention will be described with reference to FIG. The same parts as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. In this embodiment, as shown in the figure, a power choke coil PCC-3 is inserted into the negative line of the AC input power supply. The power choke coil PCC-3 are those windings N ₁ and the winding N ₃ becomes connected in series, the ends of the winding N ₁ is connected to the AC power source 1 side, end of the winding N ₃ Is connected to the connection point between the diodes D ₂ and D ₄ of the rectifying bridge circuit 3. Then, the impedance of the winding N ₁ and L _N1, the impedance of the winding N ₃ and L _N3, impedance L _N1 is set to correspond to the power factor correction when the AC input voltage of 100V system, whereas Impedance L
_N3 is the combined value of L _N1 + L _N3 and the AC input voltage is 200V
The inductance is set to be L _N2 (the same inductance as the winding N _{2 in} FIG. 1) corresponding to the power factor improvement in the case of the system. For example, as in the previous embodiment, L _N1 = 6 mH,
Assuming that L _N2 = 30 mH, L _N3 = L _N2 −L _N1 (30−
6) = 24 mH, and L _N3 is set to about 24 mH. The switch SW ₁ is connected one end to the connection point of the smoothing capacitor C ₁ and C _2, the other end is connected to the tap output terminal of the power choke coil PCC-3 as shown in FIG. .

FIG. 6C shows an example of the structure of the power choke coil PCC-3. The front part is shown by a cross section. Power choke coil PCC-3 in this figure, for example, it is constructed by winding the winding N ₂ of windings N ₁ and small cross-sectional area of the larger cross-sectional area relative to the EE type core 10 of laminated silicon steel plates or the like You.

Therefore, in the power supply circuit provided with the power factor improving rectifier circuit having the above configuration, when the AC input voltage is 150 V or less, the operation as shown in the following equalizing circuit of FIG. That is, in this case, the AC input voltage is 15
Because it is less 0V, conduction state is obtained triac T ₁ is being turned on in the switch SW _1. As a result, during a period in which the AC input voltage is positive, the AC current flows as shown by the solid line in the figure, AC power source 1 → diode D ₃ → smoothing capacitor C ₁ → switch SW ₁ → winding N ₁ → AC power source 1 Flows in Further, the AC current during the period in which the AC input voltage is negative is changed from the AC power supply 1 to the winding N ₁ as shown by the broken line in the figure.
→ switch SW ₁ → smoothing capacitor C ₂ → diode D
₁ → It flows on the path of AC power supply 1. Incidentally, the winding N ₃ is not an open In this case, although a state of being connected between the winding N ₁ and the diode D _4, inductance is winding N ₁ and the inductance of 6MH 30
When comparing the AC impedance of the winding N ₃ of mH,
Because more of the winding N ₃ becomes large, there is no possibility that the AC input voltage AC current in the negative period flows into the smoothing capacitor C ₁ via the winding N _3.

When the AC input voltage is 150 V or more, the operation is as shown in the following equalizing circuit of FIG. In this case, the triac T ₁ in the switch SW ₁ is turned off, that path which connects the tap outputs of the smoothing capacitor C _1, the connection point of the C ₂ and the power choke coil PCC-3 is to be cut off Become. In this state, when the AC input voltage is positive, the AC current is as shown by the solid line in the figure, AC power source 1 → diode D ₃ → smoothing capacitor C ₁ → smoothing capacitor C ₂ → diode D ₂ → power choke coil PCC -3 (winding N ₃ → winding N ₁ ) →
It flows on the path of the AC power supply 1. Further, the AC current during the period when the AC input voltage is negative is: AC power supply 1 → power choke coil PCC-3 (winding N ₁ → winding N ₃ ) → diode D ₄ → smoothing capacitor C as shown by the broken line in the figure. ₁ → smoothing capacitor C ₂ → diode D ₁ → AC power supply 1

That is, when the AC input voltage is a 100 V system, the voltage doubler rectification and smoothing operation is performed, so that the input power supply voltage becomes approximately 2%.
Although times of the rectified smoothed voltage Ei is to be obtained, this time, in the power choke coil PCC-3 that a current flows only in the winding N ₁ having an inductance L _N1, AC input voltage 100V system The power factor improvement corresponding to is performed. When the AC input voltage is 200 V, the rectifying and smoothing operation is performed by the series smoothing capacitors C ₁ and C ₂ to obtain a rectified and smoothed voltage Ei substantially corresponding to the input power supply voltage. so that the flows winding N ₁ and the winding N ₃ of PCC-3. Inductance L of the winding N ₁ as described above
_When the inductance L _N3 of _N1 and the winding N ₃ is combined,
Since the inductance is set to L _N2 (that is, L _N1 + L _N3 = L _N2 ), in this case, the AC current is the same as flowing through the power choke coil having the inductance L _N2 , and the AC input voltage is 200 V A power factor improvement corresponding to the system is performed. Although not shown, the operation waveforms of the respective main parts in this case are the same as those in the previous embodiment, assuming that the load, the set values of the inductances L _N1 and L _N2 are the same as in the previous embodiment, and the waveform diagram of FIG. It should be the same as shown in

As described above, in the power factor improving rectifier circuit of the present embodiment, it is possible to appropriately improve the power factor corresponding to a wide-range AC input voltage. In this case, as shown in FIG. since the two winding N ₁ and the winding N ₃ as described above operate on the configured as one PWW coils formed by the series connection is realized, and further the number of parts can be reduced.

The circuit configuration in each of the above embodiments is not limited to those shown in FIGS. 1 and 4, and it goes without saying that various changes can be made within the scope of the gist.

[0038]

As described above, the power factor improving rectifier circuit of the present invention is applicable to a power supply circuit which switches between normal rectifying smoothing operation and double voltage rectifying smoothing operation in response to a wide range of AC input voltage. For example, 100V AC input voltage system and 2
When the inductance of the power choke coil is selected so that the power factor is appropriately improved with the 00V system, switching is performed in accordance with on / off of a changeover switch for rectifying and smoothing operation. It is not necessary to add a switch for switching the inductance to the switch.
As a result, only one switch is required to be configured as a hybrid IC, so that the number of components including external components is reduced, and the amount of heat generated only needs to be considered for one switch. There is no need to provide a heat radiating plate, so that there is an effect that it is possible to reduce the size of the substrate, reduce the cost, and further reduce the power loss. When the AC input voltage is 100V and 200V
By realizing the power factor improvement operation with the system using a single set of power choke coils in which two windings having different inductances are connected in series, the number of components is further reduced, and the board size is further reduced. This is advantageous for reduction in cost and cost.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating an AC input voltage of 100 V system and 200 V AC according to the embodiment.
It is an equivalent circuit diagram at the time of V system.

FIG. 3 is a waveform chart showing an operation of a main part of the embodiment.

FIG. 4 is a circuit diagram of another embodiment of the present invention.

FIG. 5 is a diagram showing another embodiment in which the AC input voltage is 100 V and 2
It is an equivalent circuit diagram at the time of 00V system.

FIG. 6 is a perspective view showing a power choke coil.

FIG. 7 is a circuit diagram showing a conventional example.

FIG. 8 is a diagram showing the relationship between the inductance and the power factor of a power choke coil.

FIG. 9 is a circuit diagram showing a conventional example.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 AC power supply 2 Line filter transformer 3 Rectifier bridge circuit SW ₁ , SW ₂ switch T ₁ Triac PCC-1, PCC-2, PCC-3 Power choke coil N ₁ N ₂ , N ₃ winding C ₁ , C ₂ Smoothing capacitor

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-59-148564 (JP, A) JP-A-59-181970 (JP, A) JP-A-55-103082 (JP, A) 344731 (JP, A) JP-A-4-359674 (JP, A) JP-A 62-4893 (JP, U) JP-A 59-99695 (JP, U) (58) Fields investigated (Int. ⁷ , DB name) H02M 7/06 H02M 7/10

Claims (2)

(57) [Claims] A pair of AC voltage input terminals and a pair of DC output
An input terminal between the pair of AC voltage input terminals.
AC voltage from a source is applied to the pair of DC output terminals.
A diode bridge that outputs DC output voltage from one of the
And a pair of AC voltage inputs of the diode bridge rectifier circuit.
A first choke connected between one of the terminals and the AC power supply
Coil and the pair of DC outputs of the diode bridge rectifier circuit
A first connector to which a DC output voltage from one of the terminals is supplied.
A series circuit of a capacitor and a second capacitor, and a connection point between the first capacitor and the second capacitor;
And an AC power supply side of the first choke coil.
And an inductor smaller than the first choke coil.
The direct connection between the second choke coil having a closet and the switch
Detects the magnitude of the AC voltage from the column circuit and AC power supply
If the magnitude of the AC voltage from
Turn off the switch and increase the AC voltage from the AC power supply.
If the magnitude is less than the predetermined value, switch off the switch.
And a detection circuit for turning on the power supply , wherein the magnitude of the AC voltage from the AC power supply is greater than or equal to the predetermined value.
Switch, turn off the switch and
Rectifier circuit and the first and second capacitors
Perform full-wave rectification and smoothing operation, and
A current is caused to flow through the first choke coil,
The magnitude of the AC voltage from the power supply is less than the predetermined value.
The switch is turned on and the diode
Double the bridge rectifier circuit and the first and second capacitors
Perform voltage rectification and smoothing operation, and
A power factor improving rectifier circuit in which a current flows through the second choke coil . 2. A pair of AC voltage input terminals and a pair of DC output terminals.
An input terminal between the pair of AC voltage input terminals.
AC voltage from a source is applied to the pair of DC output terminals.
A diode bridge that outputs DC output voltage from one of the
And a pair of AC voltage inputs of the diode bridge rectifier circuit.
The output of the intermediate tap connected between one of the terminals and the AC power supply
A choke coil having a power terminal; and the pair of DC outputs of the diode bridge rectifier circuit.
A first connector to which a DC output voltage from one of the terminals is supplied.
A series circuit of a capacitor and a second capacitor, and a connection point between the first capacitor and the second capacitor;
And the AC power supply side of the intermediate tap output terminal of the choke coil
Between the switch and the AC power supply by detecting the magnitude of the AC voltage from the AC power supply.
If the magnitude of the AC voltage from
Turn off the switch and increase the AC voltage from the AC power supply.
If the magnitude is less than the predetermined value, switch off the switch.
And a detection circuit for turning on the power supply , wherein the magnitude of the AC voltage from the AC power supply is greater than or equal to the predetermined value.
Switch, turn off the switch and
Rectifier circuit and the first and second capacitors
Perform full-wave rectification and smoothing operation, and
An electric current is supplied to the
When the magnitude of the AC voltage from is less than the predetermined value
Turn on the switch and turn on the diode bridge.
Voltage rectification circuit and the first and second capacitors.
Current from the AC power supply
It flows from the middle tap output terminal of the choke coil
Unishi was the power factor improving rectification circuit.