CN201091060Y - Single-stage power factor correction circuit - Google Patents

Abstract

The utility model provides a single-stage power factor correction circuit, it has: a first rectifier; a second rectifier; a full bridge rectifier; a capacitor; a flyback transformer; and a switch. Compared with the traditional single-stage power factor correction circuit, the utility model only needs to flow through two rectifiers in the positive half cycle and the negative half cycle, and has lower conduction loss; therefore, the temperature of the power supply can be reduced, and the voltage of the energy storage capacitor can be effectively controlled and also used as the output voltage for stabilizing.

Description

Single stage power factor correction circuit

technical field

The utility model relates to a single-stage power factor correction circuit, especially a circuit with a switch, so that the conduction paths of the positive half cycle and the negative half cycle are respectively provided, so that the current only needs to flow through two rectifiers, so as to reduce the power supply. A single-stage power factor correction circuit for the temperature of the converter.

Background technique

Single-stage power factor correction circuits are often used in high-efficiency power supplies to improve power factor. In the traditional single-stage power factor correction circuit, in the positive half cycle or the negative half cycle, the metal oxide semiconductor field effect transistor is turned on or off to make the current flow through three rectifiers to form a loop.

However, the disadvantage of the above circuit is that no matter in the positive half cycle or the negative half cycle, the current needs to flow through three rectifiers to form a loop, which will cause high conduction loss and increase the temperature of the power supply.

For the above-mentioned shortcomings, the applicant of this case once proposed a new patent application called "single-stage power factor correction circuit" to the Taiwan Patent Office of China on May 9, 2006 (the patent number is M301459, and its corresponding application number in the United States is 11/ 493,879, currently in the process of obtaining the license announcement). However, this patent still has room for improvement in terms of component reduction and reduction of heat generated by current stress.

In view of this, the utility model proposes a single-stage power factor correction circuit to improve the above shortcomings.

Utility model content

An object of the present invention is to provide a single-stage power factor correction circuit, the voltage of the energy storage capacitor can be effectively controlled, so as to reduce its manufacturing cost.

Another object of the present invention is to provide a single-stage power factor correction circuit, which can save a power diode.

Another object of the present invention is to provide a single-stage power factor correction circuit, which does not require an additional circuit for limiting the conduction ratio.

Another object of the present invention is to provide a single-stage power factor correction circuit, the power diode of which is only responsible for half of the input cycle, so as to reduce the heat generated by the current stress.

In order to achieve the above-mentioned purpose, a single-stage power factor correction circuit of the utility model is characterized in that it has:

a first rectifier, one end of which is coupled to a neutral input end;

a second rectifier, one end of which is coupled to a line input end, and the other end is coupled to the second end of the first rectifier;

A full-bridge rectifier, which has a third rectifier, a fourth rectifier, a fifth rectifier, and a sixth rectifier, wherein the positive end of the third rectifier and the negative end of the fourth rectifier are coupled to the live wire input end, the The positive terminal of the fifth rectifier and the negative terminal of the sixth rectifier are coupled to the neutral input terminal;

a capacitor, one end of which is coupled to the second end of the second rectifier, and the other end is coupled to the positive terminals of the fourth and sixth rectifiers;

A transformer, which has a first primary coil, a second primary coil and a first secondary coil, wherein one end of the first primary coil is coupled to the capacitor, and one end of the second primary coil is coupled to the negative terminals of the third rectifier and the fifth rectifier; and

A switch is a three-terminal element, the first end of which is coupled to the first primary coil and the other end of the second primary coil, the second end is coupled to a control signal, and the third end is coupled to the The other end of the capacitor can be turned on or off under the control of the control signal.

Wherein the switch is a power switch, and the power switch is an N-channel metal oxide semiconductor field effect transistor N-channel junction field effect transistor, a P-channel metal oxide semiconductor field-effect transistor or a P-channel junction field effect transistor, wherein the first The first terminal is the drain of the MOSFET, the second terminal is the gate of the MOSFET, and the third terminal is the source of the MOSFET.

Wherein the first rectifier and the second rectifier are a rectifier diode, and the transformer is a flyback transformer.

Wherein the control signal is output by an external power factor correction controller, which can first turn on the switch in the positive half cycle, let the current flow through the second rectifier and the sixth rectifier, and then turn off the switch, Let the current flow through the third rectifier and the sixth rectifier; in the negative half cycle, first turn on the switch, let the current flow through the first rectifier and the fourth rectifier, and then turn off the switch, let the current flow through the first rectifier The fifth rectifier and the fourth rectifier.

Wherein the first primary coil has N2 turns, and the second primary coil has N1 turns, so that the negative terminals of the third rectifier and the fifth rectifier have a voltage of KV _B , wherein K=N1/N2, V _B is the voltage across the capacitor.

It further has an inductor, which is connected in series between the input terminal of the live wire and the positive terminals of the second rectifier and the third rectifier, and can supply power with the capacitor at the same time, so that the change of the current is smoother.

The utility model provides a single-stage power factor correction circuit, which is characterized in that it has:

a first rectifier, one end of which is coupled to a live wire input end;

a second rectifier, one end of which is coupled to a neutral input end and the other end is coupled to the second end of the first rectifier;

A full-bridge rectifier, which has a third rectifier, a fourth rectifier, a fifth rectifier, and a sixth rectifier, wherein the positive end of the third rectifier and the negative end of the fourth rectifier are coupled to the live wire input end, the The positive terminal of the fifth rectifier and the negative terminal of the sixth rectifier are coupled to the neutral input terminal;

a capacitor, one end of which is coupled to the negative terminals of the third rectifier and the fifth rectifier, and the other end is coupled to the positive terminals of the fourth rectifier and the sixth rectifier;

A transformer, which has a first primary coil, a second primary coil and a first secondary coil, wherein one end of the first primary coil is coupled to the capacitor, and one end of the second primary coil is coupled to the negative terminals of the first rectifier and the second rectifier; and

A switch is a three-terminal element, the first end of which is coupled to the first primary coil and the other end of the second primary coil, the second end is coupled to a control signal, and the third end is coupled to the The other end of the capacitor can be turned on or off under the control of the control signal.

Wherein the switch is a power switch, the power switch can be an N-channel metal oxide semiconductor field effect transistor N-channel junction field effect transistor, a P-channel metal oxide semiconductor field effect transistor or a P-channel junction field effect transistor, wherein the first The first terminal is the drain of the MOSFET, the second terminal is the gate of the MOSFET, and the third terminal is the source of the MOSFET.

Wherein the first rectifier and the second rectifier are a rectifier diode, and the transformer is a flyback transformer.

Wherein the control signal is output by an external power factor correction controller, which can first turn on the switch in the positive half cycle, let the current flow through the first rectifier and the sixth rectifier, and then turn off the switch, Let the current flow through the third rectifier and the sixth rectifier; in the negative half cycle, first turn on the switch, let the current flow through the second rectifier and the fourth rectifier, and then turn off the switch, let the current flow through the first rectifier The fifth rectifier and the fourth rectifier.

Wherein the first primary coil has N2 turns, and the second primary coil has N1 turns, so that the negative terminals of the third rectifier and the fifth rectifier have a voltage of KV _B , wherein K=N1/N2, V _B is the voltage across the capacitor.

It further has an inductor, which is connected in series between the live wire input terminal and the positive terminals of the first rectifier and the third rectifier, and can supply power with the capacitor at the same time, so that the change of the current is smoother.

The beneficial effects of the utility model are:

In the single-stage power factor correction circuit of the utility model, the voltage of the energy storage capacitor can be effectively controlled to reduce its manufacturing cost.

The single-stage power factor correction circuit of the utility model can save one power diode.

The single-stage power factor correction circuit of the present utility model does not need an additional circuit for limiting the conduction ratio.

In the single-stage power factor correction circuit of the utility model, its power diode is only responsible for half of the input cycle, so as to reduce the heat generated by the current stress.

Description of drawings

The features and purposes of the "single-stage power factor correction circuit" of the present utility model are described in detail with the accompanying drawings and embodiments, wherein:

FIG. 1 is a schematic diagram showing a block diagram of a single-stage power factor correction circuit in a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram showing the operation of the single-stage power factor correction circuit of the present invention when the input voltage V _i is less than the voltage KV _B , greater than the voltage KV _B and greater than the voltage V _B .

FIG. 3( a ) is a schematic diagram showing the current flow direction of the single-stage power factor correction circuit in the positive half cycle of the present application.

FIG. 3( b ) is a schematic diagram showing the current flow of the single-stage power factor correction circuit of the present application in the negative half cycle.

FIG. 4 is a schematic diagram illustrating a block diagram of a single-stage power factor correction circuit according to another preferred embodiment of the present invention.

Detailed ways

Please refer to FIG. 1 , which shows a schematic block diagram of a single-stage power factor correction circuit according to a preferred embodiment of the present invention. As shown in the figure, the single-stage power factor correction circuit of the present invention includes: a first rectifier 10; a second rectifier 20; a full bridge rectifier 30; a capacitor 40; a transformer 60; and a switch 70 combined.

Wherein, the first rectifier 10 is, for example but not limited to, a rectifier diode, one end of which is coupled to a neutral (Neutral, N) input end, which can provide the effect of half-wave rectification, but this is a common power supply. known, so I will not repeat them here.

The second rectifier 20 is, for example but not limited to, a rectifier diode, one end of which is coupled to a live wire (L) input end, which can also provide the effect of half-wave rectification, but this is known in general power supplies, Therefore, it is not intended to go into details here.

The full bridge rectifier 30 has a third rectifier 31, a fourth rectifier 32, a fifth rectifier 33 and a sixth rectifier 34, wherein the positive end of the third rectifier 31 and the negative end of the fourth rectifier 32 are coupled to the The live line input terminal, the positive terminal of the fifth rectifier 33 and the negative terminal of the sixth rectifier 34 are coupled to the neutral input terminal, but this is known in general power supply, so it is not going to be described here.

One end of the capacitor 40 is coupled to the second end of the first rectifier 10 and the second rectifier 20 (i.e., the negative end), and the other end is coupled to the positive end of the fourth rectifier 32 and the sixth rectifier 34, There is a voltage V _B across it.

The transformer 60 is, for example but not limited to, a flyback transformer, which has a first primary coil 61, a second primary coil 62 and a first secondary coil 63, wherein one end of the first primary coil 61 is coupled to the One terminal of the capacitor 40 and the second primary coil 62 is coupled to negative terminals of the third rectifier 31 and the fifth rectifier 33 . In addition, the first primary coil 61 has N2 turns, and the second primary coil 62 has N1 turns, so that the negative ends of the third rectifier 31 and the fifth rectifier 33 are coupled to the second primary coil 62 There is a voltage of KV _B at , where K=N1/N2, and V _B is the voltage across the capacitor 40 .

The switch 70 is a three-terminal device, which can be any power switch, such as but not limited to an N-channel MOSFET, N-channel junction field effect transistor, P-channel MOSFET or P-channel junction field effect transistor, hereinafter referred to as MOS switch 70, its first end is coupled to the other end of the first primary coil 61 and the second primary coil 62, the second end is coupled to a control signal, and the third The terminal is coupled to the other terminal of the capacitor 40, which can be turned on or off under the control of the control signal. Wherein, the second end is the gate (Gate) of the metal oxide semiconductor field effect transistor 70, the first end is the drain (Drain) of the metal oxide semiconductor field effect transistor 70, and the third end is the metal oxide semiconductor field effect transistor 70. The source of the semiconductor field effect transistor 70 (Source). Wherein, the control signal is output by an external power factor correction controller (not shown).

Please refer to FIG. 2 , which shows a schematic diagram of the operation of the single-stage power factor correction circuit of the present invention when the input voltage V _i is less than the voltage KV _B , greater than the voltage KV _B and greater than the voltage V _B .

As shown in the figure, during operation, when the input voltage V _i is lower than the voltage KV _B , the two ends of the first rectifier 10 form a reverse bias, so the second rectifier 20 is in a cut-off state, and the circuit will be powered by V _B at this time. The relevant circuits on the secondary side are discharged, so the current I _in at the input is zero.

As shown in the figure, when the input voltage V _i is greater than the voltage KV _B , both ends of the third rectifier 31 form a forward bias, so they are in a conduction state, and the two ends of the second rectifier 20 are still in a reverse bias, and the circuit will now be composed of V _i and V _B supply power at the same time, and I _in is not zero, but because of the initial conduction stage, its current value is very small.

As shown in the figure, when the input voltage V _i is greater than the voltage V _B , the two ends of the second rectifier 20 form a forward bias, so they are in a conduction state, and the two ends of the third rectifier 31 are also in a forward bias, so the circuit will be changed by V _i supplies power, and when it is close to the peak voltage (V _pk ), it is directly supplied by V _i , so its current value is also close to the peak value. After the peak value (V _pk ) is exceeded, the input voltage V _i gradually decreases, so it returns to the above-mentioned stage, thus completing a cycle of a positive half cycle.

Therefore, the single-stage power factor correction circuit of the present invention can not only save the rectifier coupled to the input terminal of the capacitor 40, but also reduce the voltage V _B across the capacitor 40, so as to further reduce the procurement cost of parts.

Please refer to FIG. 3( a ), which shows a schematic diagram of the current flow of the single-stage power factor correction circuit of this case in the positive half cycle. As shown in the figure, when the power is supplied by V _i , during the positive half cycle, the switch 70 can be turned on first under the control of the control signal, so that the current flows through the second rectifier 20, The switch 70 and the sixth rectifier 34 return to the neutral input terminal (N) to form a current loop; The six rectifiers 34 then go back to the neutral input (N) to form the current loop.

Please refer to FIG. 3( b ), which shows a schematic diagram of the current flow of the single-stage power factor correction circuit of this case in the negative half cycle. As shown in the figure, during the negative half cycle, controlled by the control signal, the switch 70 can be turned on first, allowing current to flow from the neutral input terminal (N) through the first rectifier 10, the switch 70 And the fourth rectifier 32 returns to the live wire input terminal (L) to form a current loop; then the control signal closes the switch 70, allowing current to flow through the fifth rectifier 33 and the fourth rectifier 32 from the neutral input terminal (N) Return to the Line input (L) to form a current loop.

Therefore, no matter during the positive half cycle or the negative half cycle, the single-stage power factor correction circuit of the present invention only needs to pass through two rectifiers, so it has lower conduction loss, and thus can reduce the temperature of the power supply. Therefore, the single-stage power factor correction circuit of the present invention is indeed progressive compared with the single-stage power factor correction circuit of the prior art.

In addition, the single-stage power factor correction circuit of the present invention further has an inductor 80, which is connected in series between the live wire input terminal (L) and the positive terminals of the second rectifier 20 and the third rectifier 31, which Electric energy can be stored and supplied simultaneously with the capacitor 40, so that the input current changes more smoothly.

Please refer to FIG. 4 , which shows a schematic block diagram of a single-stage power factor correction circuit according to another preferred embodiment of the present invention. As shown in the figure, the single-stage power factor correction circuit of the present invention includes: a first rectifier 110; a second rectifier 120; a full-bridge rectifier 130; a capacitor 140; a transformer 160; and a switch 170 combined.

Wherein, the first rectifier 110 is, for example but not limited to, a rectifier diode, one end of which is coupled to a live wire (L) input end, which can provide the effect of half-wave rectification, but this is known in general power supply , so it will not be described here.

The second rectifier 120 is, for example but not limited to, a rectifier diode, one end of which is coupled to a neutral (Neutral, N) input end, which can also provide the effect of half-wave rectification, which is not available in general power supplies. Those who know, so I will not repeat it here.

The full bridge rectifier 130 has a third rectifier 131, a fourth rectifier 132, a fifth rectifier 133 and a sixth rectifier 134, wherein the positive terminal of the third rectifier 131 and the negative terminal of the fourth rectifier 132 are coupled to the The live line input terminal, the positive terminal of the fifth rectifier 133 and the negative terminal of the sixth rectifier 134 are coupled to the neutral input terminal, but this is known in common power supplies, so it will not be described here.

One end of the capacitor 140 is coupled to the negative terminals of the third rectifier 131 and the fifth rectifier 133 , and the other end is coupled to the positive terminals of the fourth rectifier 132 and the sixth rectifier 134 , and has a voltage V _B thereon.

The transformer 160 is, for example but not limited to, a flyback transformer, which has a first primary coil 161, a second primary coil 162 and a first secondary coil 163, wherein one end of the first primary coil 161 is coupled to the The capacitor 140 and one terminal of the second primary coil 162 are coupled to negative terminals of the first rectifier 110 and the second rectifier 120 . In addition, the first primary coil 161 has N2 turns, and the second primary coil 162 has N1 turns, so that the negative terminals of the first rectifier 110 and the second rectifier 120 are coupled to the second primary coil 162 There is a voltage of KV _B at , where K=N1/N2, and V _B is the voltage across the capacitor 140 .

The switch 170 is a three-terminal device, which can be any power switch, such as but not limited to an N-channel MOSFET, N-channel junction field effect transistor, P-channel MOSFET or P-channel junction field effect transistor, hereinafter referred to as MOS switch 170, its first end is coupled to the first primary coil 161 and the other end of the second primary coil 162, the second end is coupled to a control signal, and the third The terminal is coupled to the other terminal of the capacitor 140, which can be turned on or off under the control of the control signal. Wherein, the second terminal is the gate (Gate) of the metal oxide semiconductor field effect transistor 170, the first terminal is the drain (Drain) of the metal oxide semiconductor field effect transistor 170, and the third terminal is the metal oxide semiconductor field effect transistor 170. The source of the semiconductor field effect transistor 170 (Source). Wherein, the control signal is output by an external power factor correction controller (not shown).

In the positive half cycle, the switch 170 can be turned on first to allow the current to flow through the first rectifier 110 and the sixth rectifier 134, and then the switch 170 is turned off to allow the current to flow through the third rectifier 131 and the sixth rectifier 134 ; During the negative half cycle, first make the switch 170 conduction, allow the current to flow through the second rectifier 120 and the fourth rectifier 132, then make the switch 170 off, allow the current to flow through the fifth rectifier 133 and the fourth rectifier 132 . In this way, the effect of the above-mentioned embodiment can also be achieved. For the principle, please refer to the above-mentioned description, which will not be repeated here.

In addition, the single-stage power factor correction circuit of the present invention further has an inductor 180, which is connected in series between the live wire input terminal (L) and the positive terminal of the first rectifier 110 and the third rectifier 131, which Electric energy can be stored and powered simultaneously with the capacitor 140, so that the input current changes more smoothly.

What is disclosed in this case is a preferred embodiment, and any partial change or modification derived from the technical idea of this case and easily deduced by a person familiar with the technology does not depart from the scope of the patent right of this case.

Claims (12)

1. A single-stage power factor correction circuit, characterized in that it has: a first rectifier, one end of which is coupled to a neutral input end; a second rectifier, one end of which is coupled to a line input end, and the other end is coupled to the second end of the first rectifier; A full-bridge rectifier, which has a third rectifier, a fourth rectifier, a fifth rectifier, and a sixth rectifier, wherein the positive end of the third rectifier and the negative end of the fourth rectifier are coupled to the live wire input end, the The positive terminal of the fifth rectifier and the negative terminal of the sixth rectifier are coupled to the neutral input terminal; a capacitor, one end of which is coupled to the second end of the second rectifier, and the other end is coupled to the positive terminals of the fourth and sixth rectifiers; A transformer, which has a first primary coil, a second primary coil and a first secondary coil, wherein one end of the first primary coil is coupled to the capacitor, and one end of the second primary coil is coupled to the negative terminals of the third rectifier and the fifth rectifier; and A switch is a three-terminal element, the first end of which is coupled to the first primary coil and the other end of the second primary coil, the second end is coupled to a control signal, and the third end is coupled to the The other end of the capacitor can be turned on or off under the control of the control signal. 2. The single-stage power factor correction circuit as claimed in claim 1, wherein the switch is a power switch, and the power switch is an N-channel metal-oxide-semiconductor field-effect transistor, an N-channel junction field-effect transistor, a P channel metal oxide semiconductor field effect transistor or p channel junction field effect transistor, wherein the first terminal is the drain of the metal oxide semiconductor field effect transistor, the second terminal is the gate of the metal oxide semiconductor field effect transistor, the The third terminal is the source of the MOSFET. 3. The single-stage power factor correction circuit as claimed in claim 1, wherein the first rectifier and the second rectifier are rectifier diodes, and the transformer is a flyback transformer. 4. The single-stage power factor correction circuit as claimed in claim 1, wherein the control signal is output by an external power factor correction controller, which can first turn on the switch in the positive half cycle , let the current flow through the second rectifier and the sixth rectifier, then turn off the switch, let the current flow through the third rectifier and the sixth rectifier; in the negative half cycle, first turn on the switch, let the current flow through the The first rectifier and the fourth rectifier, and then the switch is closed, so that the current flows through the fifth rectifier and the fourth rectifier. 5. The single-stage power factor correction circuit as claimed in claim 1, wherein the first primary coil has N2 turns, and the second primary coil has N1 turns, so that the third rectifier and the fifth The negative terminal of the rectifier has a voltage of KV _B , where K=N1/N2, and V _B is the voltage across the capacitor. 6. The single-stage power factor correction circuit as claimed in claim 1, further comprising an inductor connected in series between the live wire input end and the positive terminals of the second rectifier and the third rectifier, It can be powered simultaneously with this capacitor to make the change of current more gradual. 7. A single-stage power factor correction circuit, characterized in that it has: a first rectifier, one end of which is coupled to a live wire input end; a second rectifier, one end of which is coupled to a neutral input end and the other end is coupled to the second end of the first rectifier; A full-bridge rectifier, which has a third rectifier, a fourth rectifier, a fifth rectifier, and a sixth rectifier, wherein the positive end of the third rectifier and the negative end of the fourth rectifier are coupled to the live wire input end, the The positive terminal of the fifth rectifier and the negative terminal of the sixth rectifier are coupled to the neutral input terminal; a capacitor, one end of which is coupled to the negative terminals of the third rectifier and the fifth rectifier, and the other end is coupled to the positive terminals of the fourth rectifier and the sixth rectifier; A transformer, which has a first primary coil, a second primary coil and a first secondary coil, wherein one end of the first primary coil is coupled to the capacitor, and one end of the second primary coil is coupled to the negative terminals of the first rectifier and the second rectifier; and A switch is a three-terminal element, the first end of which is coupled to the first primary coil and the other end of the second primary coil, the second end is coupled to a control signal, and the third end is coupled to the The other end of the capacitor can be turned on or off under the control of the control signal. 8. The single-stage power factor correction circuit as claimed in claim 7, wherein the switch is a power switch, and the power switch can be an N-channel metal-oxide-semiconductor field-effect transistor, an N-channel junction field-effect transistor, a P channel metal oxide semiconductor field effect transistor or p channel junction field effect transistor, wherein the first terminal is the drain of the metal oxide semiconductor field effect transistor, the second terminal is the gate of the metal oxide semiconductor field effect transistor, the The third terminal is the source of the MOSFET. 9. The single-stage power factor correction circuit as claimed in claim 7, wherein the first rectifier and the second rectifier are rectifier diodes, and the transformer is a flyback transformer. 10. The single-stage power factor correction circuit as claimed in claim 7, wherein the control signal is output by an external power factor correction controller, which can first turn on the switch in the positive half cycle , let the current flow through the first rectifier and the sixth rectifier, then turn off the switch, let the current flow through the third rectifier and the sixth rectifier; in the negative half cycle, first turn on the switch, let the current flow through the The second rectifier and the fourth rectifier close the switch, so that the current flows through the fifth rectifier and the fourth rectifier. 11. The single-stage power factor correction circuit as claimed in claim 7, wherein the first primary coil has N2 turns, and the second primary coil has N1 turns, so that the third rectifier and the fifth The negative terminal of the rectifier has a voltage of KV _B , where K=N1/N2, and V _B is the voltage across the capacitor. 12. The single-stage power factor correction circuit as claimed in claim 7, further comprising an inductor connected in series between the live wire input end and the positive terminals of the first rectifier and the third rectifier, It can be powered simultaneously with this capacitor to make the change of current more gradual.

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