JPH07250473A - Power factor improving rectifier circuit - Google Patents

Abstract

PURPOSE:To obtain a power factor improving rectifier circuit for which reduc tion of a board size, the cost and a power loss and others are realized, on the occasion when the improvement of a power factor by a choke input method is made so properly as to correspond to an AC input voltage of a wide range. CONSTITUTION:Regarding a power choke coil PCC-3 having a construction wherein a winding N1 for which an inductance LN1 corresponding to the improvement of a power factor in the case of an AC power supply input of a 100V system is set and a winding N3 for which suchaninductance LN3 as to be LN3= LN2-LN1 when an inductance corresponding to the improvement of the power factor in the case of the AC power supply input of a 200V system is made LN3, are connected in series, the coil is inserted in a line on the minus side of the AC power supply input in such a manner that the end part of the winding N. is connected onto the power supply input side and the end part of the winding N3 onto the rectifying circuit side. A switch SW1 for switching a rectifyingsmoothing operation is connected in such a manner that it is inserted between between the node of smoothing capacitors C1 and C.2 and a tap output of the windings N1 and N3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power factor correction rectifier circuit provided for improving the power factor of a power supply circuit, and particularly to a 200 V AC power supply input to a power supply circuit.
It is suitable for application to a so-called wide range power supply circuit that is compatible with AC power input up to V system.

[0002]

2. Description of the Related Art As a power supply circuit, a so-called world-wide power supply circuit is widely used which is widely applicable to, for example, 100 V AC power input to 200 V AC power input. For example, the operation of the rectifying / smoothing circuit section is switched depending on whether the AC power input is 100V system or 200V system, and when the AC power input is 100V system, the voltage doubler rectifying / smoothing operation is executed, while the AC power input Is a 200V system, a normal rectifying / smoothing operation is executed and, for example, by supplying it to a power supply circuit unit in a subsequent stage, a predetermined DC voltage can be obtained regardless of fluctuations in the AC input voltage. Are known.

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

The circuit diagram of FIG. 7 shows an example of a power supply circuit in which a choke input type power factor correction rectifier circuit is provided for the above worldwide power supply circuit. A power supply is shown, and both poles of the AC power supply 1 are respectively connected to the windings of the line filter transformer 2. Further, Ci inserted between the positive electrode line and the negative electrode line in the latter stage of the line filter transformer 2 indicates an across capacitor and forms a low pass filter together with the line filter transformer 2. The PCC-11 inserted between the line filter transformer 2 and the input end of the rectifying bridge circuit 3 (connection point of the diodes D ₁ and D ₃ ) in the positive line represents a power choke coil, as shown in the figure. It consists of winding N ₁₁ . That is, in the power supply circuit of this figure, the power choke coil PCC-1
The action of the inductance L _N11 of the first winding N ₁₁ expands the conduction angle of the current flowing to the AC input, thereby improving the power factor. Reference numeral 3 is a rectifying bridge circuit composed of diodes D ₁ , D ₂ , D ₃ , and D ₄ , and the full-wave rectified input voltage 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 form a DC voltage Ei, which is supplied to a constant power supply circuit such as a switching power supply circuit at a subsequent stage (not shown).

Further, SW ₁ indicated by a broken line is a switch for switching between the double voltage rectifying and smoothing operation and the normal rectifying and smoothing operation. The switch SW ₁ has, for example, the triac T ₁ shown in the drawing as a switch element, and In addition, it is a hybrid IC including an on / off control circuit for the triac T _{1 and} the like. In this case, the triac T ₁ of the switch SW ₁ is connected between the connection points of the smoothing capacitors C ₁ and C ₂ and the negative side of the rectifying bridge circuit 3 (connection points of the diodes D ₂ and D ₄ ) as shown in the figure. It is provided so as to be inserted into. R ₁ is a resistance,
C ₃ -C ₆ are capacitors, D ₅ represents a diode, are each external components of the switch SW _1. Then, in these external parts, the detection voltage V _D obtained by rectifying and smoothing the AC input voltage is obtained by the rectifying circuit including the capacitor C ₃ and the diode D ₅ . And the switch SW
_{In the case of 1} , for example, the AC power source 1 based on this detection voltage V _D
When 150 V or less is supplied, it is turned on to be in a conductive state, and when 150 V or more is supplied, it is turned off to be in a non-conductive state.
That is, in this case, when the AC power supply 1 is a so-called 100V system, the switch SW ₁ is turned on, and the AC power supply 1
Is a so-called 200V system, it will be turned off. A resistor R ₁ and capacitors C _{4 to} C ₆ , which are other external parts, are protection circuits provided for measures against surge current when the triac T ₁ is turned on and off, noise of the gate signal of the triac T ₁ , and the like. Is formed.

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

That is, at this time, the smoothing capacitor C ₁ ,
By charging C _{2 in} the positive period and the negative period, respectively, the voltage Ei is 200 times as much as the input voltage of the AC power supply 1.
The voltage doubler rectifying and smoothing operation is performed to obtain the V system voltage.

On the other hand, when the AC voltage of 200 V system is supplied as the AC power source 1, the switch SW ₁ is turned off. In this case, the current during the period when the AC input voltage is positive is as follows: 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
It will flow in the route of the winding 2b of T to the AC power supply 1.
Also, while the AC input voltage is negative, the current is AC power source 1 →
Winding 2b of the line filter transformer LFT → diode D ₄ → smoothing capacitor C ₁ → smoothing capacitor C ₂ → diode D ₁ → power choke coil PCC-11 → winding 2a of the line filter transformer LFT → flow in the path of the AC power supply 1 . That is, in this case, the bridge rectifier circuit 2
And the normal rectifying and smoothing operation by the capacitors C ₁ and C _{2 in} series is performed to respond to the input voltage.
A V-system DC voltage Ei is obtained.

By switching the switch SW ₁ in this manner, the voltage doubler rectifying and smoothing operation is performed when the AC power supply input is 100V system, while the normal full-wave rectifying and smoothing operation is performed when the AC power supply input is 200V system. The operation configures a power supply circuit corresponding to a wide range AC input voltage.

[0010]

By the way, in the configuration shown in FIG. 7, the power factor should be improved to about 0.6 to 0.75 under the condition that the load power is constant (about 200 W), for example. In this case, since the conduction angle of the AC current becomes smaller as the AC power supply input rises, the inductance L _N11 of the winding N ₁₁ of the power choke coil PCC-11 is actually the case when the AC power supply input is 100V system. For example, about 6 mH is required, and about 30 mH is required when the AC power supply input is a 200 V system. The peak of the current flowing through the winding N ₁₁ at this time is 1 when the AC power input is 1.
In the case of the 00V system, it is up to about 8A, and in the 200V system, the current flowing through the inductance L _N11 is about 3.5A. Therefore, assuming that a winding N ₁₁ having an inductance L _N11 of 6 mH is used as the power choke coil PCC-11, a force of about 0.75 is applied when the AC power input is 100 V as shown by the alternate long and short dash line in FIG. The power factor is guaranteed, but when the AC power input rises to 230V, the power factor drops to about 0.5, which is below the target value. Therefore, this inductance value L _N11 is 6 m
H is not appropriate.

The power choke coil PCC-11
Assuming that a winding N ₁₁ having an inductance L _N11 of 30 mH is used as shown in FIG. 8, a power factor of 0.75 or more can be secured even when the AC power input is 100 V and 230 V. Becomes However, in order to set the inductance L _N11 of the power choke coil PCC-11 to 30 mH and to cope with the DC current when the AC input voltage is 100 V, for example, the winding N ₁₁ is wound with a urethane wire having a large cross-sectional area. Therefore, it is necessary to suppress the DC resistance to be small, and as a result, the power choke coil PCC-11 becomes large and the weight also increases. As described above, when it is attempted to improve the power factor by actually using the circuit configuration shown in FIG. 7 to cope with a wide range AC input voltage, one large power choke coil can reduce the AC input voltage 1
Since a large current and a small inductance at the time of 00V and a small current and a large inductance at the time of the AC input voltage must be realized, the weight and the cost are increased.

Therefore, for example, as shown in the circuit diagram of FIG. 9, two power choke coils PCC-1 and PCC-2 are used to actually form a power factor correction rectifier circuit corresponding to a wide range AC input voltage. It is considered to make up.
In this figure, the same parts as those in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted. 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 inserted between the end of the capacitor C ₃ and the switch is a switch for switching between the voltage doubler rectifying / smoothing operation and the normal rectifying / smoothing operation, and like the capacitor C ₃ shown in FIG.
The AC input voltage rectified by the diode D ₅ and the diode D ₅ is used as a detection voltage. For example, when the AC input voltage is detected to be 150 V or less, the triac T ₁ is turned on and 1
When it is detected that the voltage is 50 V or more, it is turned off. Further, PCC-1 inserted between the connection point of the switch SW ₁ and the smoothing capacitors C ₁ and C ₂ indicates a power choke coil provided for improving the power factor when the AC input voltage is 100 V, and the winding The inductance L _{N1 of} N ₁ is, for example, 6 mH.

SW ₂ connected in parallel to both ends of the power choke coil PCC-2 is a switch provided for turning on / off the bypass of the power choke coil PCC-2, and is represented by a switch SW ₁ . Similarly, it is configured as a hybrid IC incorporating a triac T ₂ as a switching element. Also in this switch SW ₂ , a voltage obtained by rectifying and smoothing an AC input voltage by a diode D ₁₅ and a capacitor C ₁₃ which are external components is used as a detection voltage, and when the detection voltage corresponds to, for example, 150 V or less, a triac is used. T ₂ is turned on, and when it corresponds to 150 V or higher, it is turned off. In addition, the resistor R ₁₁ and the capacitor C ₁₄
C ₁₆ is an external component for measures against surge current and gate signal noise. The PCC- inserted between the winding 2a of the line filter transformer 2 and the input end 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 accommodating a power factor improvement of an AC input voltage of 200 V system. In this power choke coil PCC-2, the inductance L _N2 of the winding N ₂ is set to 30 mH, for example.

The power supply circuit having the power factor correction rectifying circuit having the configuration shown in FIG. 9 operates as follows. First,
When the AC input voltage is 100 V, both the switch SW ₁ and the switch SW ₂ are turned on and become conductive as described above. In this state, the current during the period when the AC input voltage is positive is as follows: 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 → flows in the path of AC power supply 1. On the other hand, while the AC input voltage is negative, the current is AC power supply 1 → winding 2b of the line filter transformer LFT → switch SW ₁ → power choke coil PCC-1 → smoothing capacitor C ₂ → diode D ₁ → switch SW ₂ → Line filter transformer L
The FT winding 2a flows in the path of 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, the AC current flows through the power choke coil PCC-1 as described above, and the inductance L _N1 of the winding N ₁ of the power choke coil PCC-1 is, for example, 6
Since it is set to mH, power factor improvement suitable for the condition of large current and small inductance when the AC input voltage is 100V is performed.

Next, when the AC input voltage is 200 V, both the switch SW ₁ and the switch SW ₂ are turned off and become non-conductive. As a result, the path passing through the power choke coil PCC-2 via the switch SW ₂ is cut off, and the path of the power choke coil PCC- ₁ is opened by SW ₁ . Therefore, in this state, the current during the period when the AC input voltage is positive is as follows: 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 → It flows in the path of the diode D ₂ → the winding ₂ b of the line filter transformer LFT → the AC power supply 1. In addition, while the AC input voltage is negative, the current is AC power supply 1 → 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
It flows in the path of C-2 → the winding 2a of the line filter transformer LFT → the AC power supply 1.

That is, when the AC input voltage is 200 V, the rectification by the bridge rectification circuit 2 and the capacitor C
_{Although the} smoothing operation by ₁ and C ₂ is performed and the DC voltage Ei responding to the input voltage is obtained, a current flows through the power choke coil PCC-2 in the current path at this time. The inductance L _N1 of the winding N ₁ of the power choke coil PCC-2 is set to, for example, 30 mH, so that a small current large inductance, which is a condition for improving the power factor when the AC input voltage is 200 V, can be obtained. Become. Thus, in the case of 100V AC input voltage system and 2
In the case of a 00V system, two types of power choke coils that meet the respective conditions are provided, and by switching between the two switches SW ₁ and SW ₂ , switching of the rectifying and smoothing operation according to the AC input voltage and the power choke coil. If the selection switching is performed, it is possible to obtain a rectifier circuit that improves the power factor in response to a wide range AC input voltage.

However, in the configuration as described above,
Two switches SW ₁ and SW ₂ that are on / off controlled by the AC input voltage are required. Since these switches are composed of hybrid ICs as described above, the area occupied by them on the board is considerable, and in addition to the fact that a relatively large number of external parts are required as shown in the figure, There is a problem that it is very difficult to increase the number of parts and the board size is reduced accordingly, and the cost is high. In addition, 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 Fever cannot be ignored. For this reason, it becomes necessary to provide a heat dissipation plate, which inevitably leads to an increase in the size of the substrate and the like, and there is a problem in that the rectification efficiency also decreases.

[0018]

In view of the above problems, therefore, the power factor correction rectifier circuit of the present invention appropriately performs power factor correction by the choke input method in response to a wide range AC input voltage. In doing so, it is an object of the present invention to obtain a power factor correction rectifier circuit in which the substrate size is reduced, the cost is reduced, and the power loss is reduced.

Therefore, the diode bridge rectifier circuit connected to the AC power supply input via the first AC reactor and the first and the series connected so as to be charged by the rectified output of the diode bridge rectifier circuit. Second
Smoothing capacitor and a switch that is turned off when the AC power supply exceeds a predetermined value, and is turned on otherwise, by the switch.
Between the terminal to which the AC reactor is connected and the connection point of the first and second smoothing capacitors are connected via the second AC reactor having an inductance smaller than the first reactance. We decided to construct an improved rectification circuit.

A diode bridge rectifier circuit connected to an AC power supply input via an AC reactor having an intermediate tap, and a first series connected so as to be charged by a rectified output of the diode bridge rectifier circuit.
And a second smoothing capacitor, and a switch that is turned off when the AC power source becomes equal to or higher than a predetermined value, and is turned on otherwise, by the switch, the intermediate tap of the AC reactor and the first and second The power factor correction rectifier circuit is configured so that the connection point of the second smoothing capacitor is connected.

[0021]

According to the above structure, a power choke coil having an inductance capable of improving the power factor according to the AC input voltage is provided with the ON / OFF of the switch for switching between the normal rectifying / smoothing operation and the double voltage rectifying / smoothing operation. It becomes possible to select. The power choke coil is connected to the first winding and the second winding.
If the inductance is configured so that the power factor can be improved according to the AC input voltage, the power choke coil should be one in the circuit. be able to.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power factor correction 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 correction rectifier circuit according to the present embodiment. The same parts as those in FIG. 9 described above are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment as well, the power choke coil PCC-1 corresponds to the power factor improvement when the AC input voltage is 100V system.
For example, the power choke coil PCC-2 has a large current and a small inductance, and the power choke coil PCC-2 has, for example, a small current and a large inductance so as to cope with the power factor improvement when the AC input voltage is 200V. .

6 (a) and 6 (b) 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.
As shown in (a), an EE type core 10 made of, for example, a silicon steel plate (in this case, a laminated type) is wound with a thick wire N ₁ for large current as shown in the figure. And
The power choke coil PCC-2 is also shown in FIG.
As shown in FIG. 6B, a thin wire N ₂ for small current is wound around the EE type core 10 in which silicon steel plates are laminated as shown in the figure. Further, the switch SW ₁ in the present embodiment switches between the voltage doubler rectifying and smoothing operation and the normal rectifying and smoothing operation in the same manner as described with reference to FIG. 9, and is configured as a hybrid IC.
When the voltage is 50 V or less, the conduction of the triac T ₁ is turned on,
When the voltage is 150 V or more, it is turned off.

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 in the line on the negative side of the AC power source as shown in the figure. It is inserted between the input terminal (connection point between the diodes D ₂ and D ₄ ). The switch SW ₁ has one end connected to the power choke coil PCC-1 side and the other end connected to the power choke coil PCC-2 and the winding 2 b of the line filter transformer 2 in the line on the negative side of the AC power supply. It is connected to the connection point with.

Therefore, 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. 2A equivalently shows the operation of the power supply circuit shown in FIG. 1 when the AC input voltage is 100 V system (150 V or less in this case), and FIG. The operation in the case of 200 system (150 V or more) is equivalently shown. Further, FIG. 3A shows a waveform of the _AC input voltage V _AC , and FIGS. 3B to 3E respectively show the AC input current I _AC when the AC input voltage is 150 V or less.
Rectification smoothing voltage Vi, voltage V across smoothing capacitor C _1
C1 shows the waveform of the voltage V _C2 across the smoothing capacitor C ₂ , and FIGS. 3 (f) to 3 (h) show that the AC input voltage is 15
AC input current I _AC , rectified and smoothed voltage V in the case of 0 V or more
i shows the waveforms of the voltage V _C1 across the smoothing capacitor C ₁ and the voltage V _C2 across the smoothing capacitor C ₂ . However, FIG. 3 shows the 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 and brought into a conductive state as shown in FIG. 2 (a). Then, in this state, during the period when the AC input voltage is positive (the period indicated by 0 to π and 2π to 3π in FIG. 3A), the current flows as indicated by the solid arrow in FIG. 2A. . In other words, AC power supply 1 → diode D ₃
→ Smoothing capacitor C ₁ → Power choke coil PCC-
A path of 1 → triac T ₁ → AC power supply 1 is formed, and a charging current flows to the smoothing capacitor C ₁ . Further, the current when the AC input voltage is negative as in the period shown by π to 2π in FIG. 3A, the AC power supply 1 → triac T ₁ →
Power choke coil PCC-1 → Smoothing capacitor C
₂ → diode D ₁ → AC power supply 1 path. That is, in this case, the smoothing capacitor C _{2 is} charged.

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

In this case, the power choke coil PCC-2 is inserted between the AC power source 1 and the diode D ₄ as shown in FIG. 2A, but the power choke coil has an inductance of 6 mH. PCC-1 and power choke coil PC with inductance of 30mH
When the AC impedance of C-2 is compared, the power choke coil PCC-2 becomes much larger,
As can be seen from FIGS. 3A, 3D, and 3E, in the first half of the negative half cycle of the AC input voltage, V _C1 (voltage across smoothing capacitor C ₁ )> V _C2 (smoothing capacitor C ₂ Since the voltage is at both ends), the charging current does not flow into the smoothing capacitor C ₁ via the power choke coil PCC-2 during this period. 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 and becomes in a non-conductive state as shown in FIG. 2 (b). As a result, the smoothing capacitors C ₁ and C ₂
The connection point between the connection point and the line on the negative side of the AC input power supply is cut off, and the power choke coil PCC
The terminal on the switch SW ₁ side of -1 becomes open. In this state, the AC input voltage V _AC is 0 to 0 in FIG.
During a positive period such as π, 2π to 3π period, the current flows as indicated by the solid arrow in FIG. That is, the 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 flows through the smoothing capacitors C ₁ and C ₂ connected in series. It becomes the charging operation for. In addition, the AC input voltage V _AC is shown in FIG.
In a negative period such as the period from π to 2π in (a), the current flows from the AC power supply 1 → as indicated by the broken line arrow in FIG.
Power choke coil PCC-2 → diode D ₄ → smoothing capacitor C ₁ → smoothing capacitor C ₂ → diode D ₁
→ The smoothing capacitors C ₁ and C ₂ connected in series are charged in the same manner as in the period when the _AC input voltage V _AC is positive, flowing in the path of the AC power supply 1. Therefore, in this case, the voltage V _C1 across the smoothing capacitors C ₁ and C ₂ respectively,
Both V _C2 are as shown in FIG. 3 (h).
In this way, when the AC input voltage is the 200 V system, the rectifying and smoothing operation is performed by the action of the smoothing capacitors C ₁ and C ₂ connected in series, so that the rectifying and smoothing voltage Vi substantially corresponding to the AC input voltage is obtained. (FIG. 3 (g)) is obtained. Further, at this time, for example, the power choke coil PCC-2 inductance through which the alternating current flows is set to about 30 mH, so that the conduction angle of the alternating input current I _AC is as shown in FIG.
The power factor is improved by expanding the period to τ shown in (f).

As described above, the power factor correction rectifier circuit of this embodiment performs the voltage doubler rectifying and smoothing operation when the AC power supply input is 100V system, and the normal rectifying and smoothing operation when the AC power supply input is 200V system. In order to improve the power factor by the choke input for the switchable power supply circuit as described above, when the switch SW ₁ for switching the operation is turned on, the alternating current flows through the power choke coil PCC-1. In the off state, an alternating current flows through the power choke coil PCC-2. As a result, for example, as shown in FIG. 9, the power factor improvement corresponding to the AC input voltage is realized without providing the switch SW ₂ for performing the bypass control of the power choke coil PCC-2. As described above, the switch SW ₁ or SW ₂ is composed of a hybrid IC, and various external parts are required to mount the switch SW ₁ or SW ₂ on the substrate, and heat is also generated due to the power loss. Therefore, in this embodiment, since one set of such hybrid ICs is sufficient, the number of parts to be added is reduced, and the heat generation amount is also reduced as compared with the case of two sets, so it is necessary to provide a heat dissipation plate. Also disappears.

Next, another embodiment of the present invention will be described with reference to FIG. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, as shown in the figure, the power choke coil PCC-3 is inserted in the negative line of the AC input power source. 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 of the diodes D ₂ and D ₄ of the rectifying bridge circuit 3. When the impedance of the winding N ₁ is L _N1 and the impedance of the winding N ₃ is L _N3 , the impedance L _N1 is set so as to correspond to the power factor improvement in the case of the AC input voltage of 100 V system. Impedance L
_N3 is L _N1 + L _N3 , and the combined value is AC input voltage 200V
The inductance is set to 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,
If 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 has one end connected to the connection point of the smoothing capacitors C ₁ and C ₂ and the other end connected to the tap output terminal of the power choke coil PCC-3 as shown in the figure. .

FIG. 6C shows an example of the structure of the power choke coil PCC-3. The front portion is shown by a cross section. In this figure, a power choke coil PCC-3 is constructed by winding a winding N _{1 having} a large cross-sectional area and a winding N ₂ having a small cross-sectional area around an EE type core 10 in which silicon steel plates and the like are laminated. It

Therefore, when the AC input voltage is 150 V or less in the power supply circuit having the power factor correction rectifying circuit having the above-described configuration, the operation is as shown in the following equalizing circuit of FIG. 5 (a). That is, in this case, the AC input voltage is 15
Since it is 0 V or less, in the switch SW ₁ , the triac T ₁ is turned on and a conductive state is obtained. As a result, during the period when the AC input voltage is positive, the AC current flows through the path of AC power supply 1 → diode D ₃ → smoothing capacitor C ₁ → switch SW ₁ → winding N ₁ → AC power supply 1 as shown by the solid line in the figure. Flowing in. Further, the alternating current during the period when the alternating input voltage is negative is as shown by the broken line in the figure, the alternating current power supply 1 → the winding N ₁
→ switch SW ₁ → smoothing capacitor C ₂ → diode D
₁ → It will flow in the route of AC power supply 1. Note that the winding N ₃ is not open in this case and is connected between the winding N ₁ and the diode D ₄ , but the winding N ₁ having an inductance of 6 mH and the inductance N 30
When comparing the AC impedance of the winding N ₃ of mH,
Since the winding N ₃ becomes larger, the AC current does not flow into the smoothing capacitor C ₁ through the winding N ₃ during the period when the AC input voltage is negative.

When the AC input voltage is 150 V or higher, the operation is as shown in the equalizing circuit of FIG. 5B. In this case, in the switch SW ₁ , the triac T ₁ is turned off, and the path connecting the connection point of the smoothing capacitors C ₁ and C ₂ and the tap output of the power choke coil PCC-3 is cut off. Become. In this state, in the period when the AC input voltage is positive, the AC current is, as shown by the solid line in the figure, AC power supply 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 in the path of the AC power supply 1. Further, the alternating current in the period when the alternating input voltage is negative is as shown by the broken line in the figure, alternating current power supply 1 → power choke coil PCC-3 (winding N ₁ → winding N ₃ ) → diode D ₄ → smoothing capacitor C ₁ → smoothing capacitor C ₂ → diode D ₁ → AC power source 1 will flow.

That is, when the AC input voltage is 100 V, the voltage doubler rectifying and smoothing operation is performed and the input power supply voltage is almost 2%.
The rectified and smoothed voltage Ei is doubled. At this time, in the power choke coil PCC-3, the current flows only in the winding N ₁ having the inductance L _N1. The power factor will be improved according to. Further, when the AC input voltage is 200 V system, the rectifying and smoothing operation is performed by the smoothing capacitors C ₁ and C _{2 in} series, and the rectifying and smoothing voltage Ei substantially corresponding to the input power supply voltage is obtained, and the AC current is the power choke coil. It will flow through winding N ₁ and winding N ₃ of PCC-3. As described above, the inductance L of the winding N _{1
When N1} and the inductance L _N3 of the winding N ₃ are combined,
Since the inductance is 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 of the inductance L _N2 , and the AC input voltage is 200 V. Power factor correction corresponding to the system is performed. Although not shown, the operation waveforms of the respective main parts in this case are such that the load, the set values of the inductances L _N1 and L _N2 are the same as those in the previous embodiment, and the waveform diagram of FIG. The same as shown in

As described above, even in the power factor correction rectifier circuit of this embodiment, it is possible to properly improve the power factor corresponding to the wide range AC input voltage. In this case, as shown in FIG. Further, since the above operation is realized after being configured as one PWW coil in which the winding N ₁ and the winding N ₃ are connected in series, the number of parts is further reduced.

The circuit configurations in the above embodiments are not limited to those shown in FIGS. 1 and 4, and it goes without saying that various modifications can be made within the scope of the invention.

[0038]

As described above, the power factor correction rectifier circuit of the present invention is applied to a power supply circuit that switches between a normal rectifying / smoothing operation and a double voltage rectifying / smoothing operation in response to a wide range AC input voltage. For example, AC input voltage 100V system and 2
When selecting the inductance of the power choke coil so that the power factor can be properly corrected with the 00V system, the inductance is selected according to the on / off state of the rectifying / smoothing operation changeover switch. It is not necessary to add a switch for switching the inductance to.
As a result, since only one switch is configured as a hybrid IC, the number of parts including external parts can be reduced, and the heat generation amount can be taken into consideration for one switch. It is possible to reduce the size of the substrate, reduce the cost, and reduce the power loss by eliminating the need for providing a heat sink. In addition, AC input voltage 100V system and 200V
By realizing the power factor improvement operation with the system time with one set of power choke coils in which windings having two different inductances are connected in series, the number of parts is further reduced, and the board size is further reduced. It is advantageous for the cost reduction and cost reduction.

[Brief description of drawings]

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

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

FIG. 3 is a waveform diagram 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 of another embodiment of the AC input voltage 100V system and 2
It is an equivalent circuit diagram at the time of a 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 a relationship between an inductance of a power choke coil and a power factor.

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

[Explanation of symbols]

1 AC power supply 2 Line filter transformer 3 Rectifying 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

Claims (2)

[Claims] 1. A diode bridge rectifier circuit connected to an AC power source input via a first AC reactor, and first and first series connected so as to be charged by a rectified output of the diode bridge rectifier circuit. 2 smoothing capacitor, and is turned off when the AC power supply is above a predetermined value,
In other cases, a switch means that is turned on is provided, and the switch means connects the first AC reactor input terminal connected to the first AC reactor and the connection point of the first and second smoothing capacitors. The power factor correction rectifier circuit is characterized in that the two are connected via a second AC reactor having an inductance smaller than the first reactance. 2. A diode bridge rectifier circuit connected to an AC power supply input via an AC reactor having an intermediate tap, and first and serially connected so as to be charged by a rectified output of the diode bridge rectifier circuit. A second smoothing capacitor, and is turned off when the AC power supply has exceeded a predetermined value,
In other cases, switch means that is turned on is provided, and the intermediate tap of the AC reactor and the connection point of the first and second smoothing capacitors are connected by the switch means. Power factor correction rectifier circuit.