CN105337486A - Passive-type coupling inductor soft switching circuit for power factor corrector - Google Patents

Abstract

The invention proposes a passive-type coupling inductor soft switching circuit for a power factor corrector, and the circuit comprises a power input end, a first inductor, a second diode, a power output end, a power switch, and a buffering circuit, wherein one end of the first inductor is coupled to the power input end, the positive end of the second diode is coupled to the other end of the first inductor, the power output end is coupled to the negative end of the second diode, and the buffering circuit is connected with the power switch. A circuit design employing the buffering circuit enables the waveforms of voltage and current to generate phase intersection displacement, so as to reduce switching loss.

Description

Passive Coupled Inductor Soft Switching Circuit for Power Factor Corrector

technical field

The present invention relates to a power factor corrector, and more particularly to a power factor corrector with soft switching circuit for continuous conduction mode.

Background technique

With the progress of science and technology and the development of economy, the human demand for switching converters is increasing day by day. In recent years, due to the great progress of power electronics technology, most of the electronic devices are also developing in the direction of thinner, thinner and smaller. The internal power converters also need to be designed in a thinner and shorter trend. Therefore, it has the advantages of small size and light weight. Switching power converters with advantages such as high efficiency and high efficiency have gradually replaced traditional linear converters and become the mainstream of power converters. In addition to the advantages of being small and light, the switching converter further improves the efficiency and quality of the converter.

Common operation modes of a power factor corrector (PFC) include continuous conduction mode (CCM) and discontinuous conduction mode (DCM). For low power systems, a common way to implement a power factor corrector is to use discontinuous conduction mode to control the switching mode. Conversely, continuous conduction mode is usually used instead for higher power requirements.

Generally speaking, if the boost converter in the traditional continuous conduction mode operates in the hard switching mode, there will be energy loss when the power switch is turned off and on, which is mainly due to the voltage at the moment of turning off and on. This is the switching loss due to the current delay. The main solution is to use an external circuit to generate a phase interleaving displacement of the voltage and current waveforms in order to reduce switching losses.

Contents of the invention

In view of this, the object of the present invention is to provide a passive coupled inductor soft switching circuit for a power factor corrector, which utilizes an external circuit to generate a phase-staggered displacement of the voltage and current waveforms so as to reduce switching losses.

In order to achieve the above or other purposes, the present invention proposes a passive coupled inductor soft switching circuit of a power factor corrector, which includes a power input terminal, a first inductor, one end of which is coupled to the power input terminal, a first two A pole tube, the positive end of which is coupled to the other end of the first inductor, a power output end, which is coupled to the negative end of the first diode, a power switch, and a snubber circuit, which is coupled to the power switch catch. Among them, the circuit design of the snubber circuit is used to generate phase interleaving displacement of the voltage and current waveforms, so as to reduce the switching loss.

Description of drawings

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

FIG. 2 to FIG. 7 are flow charts of circuit actuation sequences of a preferred embodiment of the present invention.

detailed description

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments will be described in detail below together with the accompanying drawings.

Please refer to FIG. 1 to FIG. 7 , which are circuit schematic diagrams and circuit actuation timing flow charts of a preferred embodiment of the present invention. The present invention proposes a passive soft switching circuit of a power factor corrector, which includes a power input terminal (10), a power output terminal (11), a first inductor (12), and a first diode (13) , a power switch (14), a third capacitor (15), a fourth capacitor (16) and a buffer circuit (20).

The power input terminal (10) is coupled to one end of the first inductor (12), and the third capacitor (15) can be coupled between the power input terminal (10) and the first inductor (12). The positive end of the first diode (13) is coupled to the other end of the first inductor (12), and the negative end of the first diode (13) is coupled to the power output end (11), And the fourth capacitor (16) is coupled in front of the power output terminal (11).

The snubber circuit (20) is coupled to the power switch (14), and the snubber circuit (20) includes a coupled inductor (21), a first capacitor (22), a second diode (23), a A third diode (24), a second capacitor (25), a fourth diode (26) and a fifth diode (27). The power switch (14) can be a metal oxide semiconductor field effect transistor or other equivalent components, and the coupled inductor (21) mainly includes a first winding group (21a) and a second winding group (21b) .

One end of the first winding group (21a) of the coupled inductor (21) is coupled between the first inductor (12) and the first diode (13), the first winding group (21a) The other end is coupled to the power switch (14). This end of the first winding group (21a) is also coupled with one end of the first capacitor (22) and the positive end of the fifth diode (27), and the positive end of the second diode (23) end is coupled with the other end of the first capacitor (22) and the negative end of the fourth diode (26), and the positive end of the fourth diode (26) is coupled in series with the second winding One end of group (21b). The positive end of the third diode (24) is coupled between the second inductor (21) and the power switch (14), and the negative end of the third diode (24) is connected to the fifth and second The negative end of the pole tube (27), the other end of the second winding group (21b) and one end of the second capacitor (25) are coupled. The negative end of the second diode (23) is coupled between the first diode (13) and the power input end (11), and the other end of the second capacitor (25) is coupled to the The negative end of the second diode (23) is at the same potential line. Wherein, the fifth diode (27) is mainly used as a protection circuit component to prevent damage to the whole circuit caused by abnormal current.

The connection relationship of each relevant unit has been described above, and the operation process will be described in the following. Firstly, the power input terminal (10) can provide the source of power, and the third capacitor (15) can provide the effect of filtering. When the power switch (14) is in the closed state, the power provided by the power input terminal is directly provided to the first inductor (12) and the first diode (13), and then the power is directly output through the power terminal (11) output, and charge the fourth capacitor (16) at the same time.

When the power switch (14) is in an open state, part of the power provided by the power input terminal (10) will flow through the first line group (21a) and the power switch (14), relatively flowing through the second The current of a diode (13) starts to drop (the input current is assumed to be constant during one switching cycle). Finally, the power provided by the power input terminal (10) will all flow through the first line group (21a) and the power switch (14), and at this time the fourth capacitor (16) will be discharged, and the discharged power will be Flow through the second capacitor (25), the second line group (21b), the fourth diode (26), the first capacitor (22), the first line group (21a) and finally through The power switch (14), and the first capacitor (22) and the second capacitor (25) store electric power due to the discharge of the fourth capacitor (16). And when the fourth capacitor (16) exhausts the stored power, the power provided by the power input terminal (10) will all flow through the second inductor (21) and the power switch (14).

Immediately after the power switch (14) is turned off, first the power provided by the first inductor (12) will flow through the first line group (21a), the third diode (24) and the second Capacitor (25). Then, when the power provided by the first winding group (21a) decreases, the power provided by the first inductor (12) also starts to flow through the first capacitor (22) and the second diode in sequence (twenty three). Finally, when the first line group (21a) fails to provide power, and the first capacitor (22) and the second capacitor (25) also fail to provide power, the overall circuit system returns to the initial state.

Based on the above description, the present invention can effectively shift the phases of the corresponding waveforms of the current and voltage waveforms during the switching time, so as to achieve the function of soft switching, thereby reducing energy loss during switching.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, this The protection scope of the invention shall be defined by the claims.

Claims (5)

1. a passive type coupling inductance soft-switching circuit for power factor corrector, is characterized in that this circuit comprises:

One power input end;

One first inductance, its one end and this power input end couple;

One first diode, the other end of its anode and this first inductance couples;

One power output end, the negative terminal of itself and this first diode couples;

One power switch;

One buffer circuit, itself and this power switch couples, and this buffer circuit includes,

One coupling inductance, it has two coiling groups, and be respectively one first coiling group and one second coiling group, and one end of this first coiling group is coupled between this first inductance and this first diode, its other end is coupled to this power switch;

One first electric capacity, its one end is coupled to this end of this first coiling group;

One second diode, its anode is coupled to the other end of this first electric capacity, and negative terminal is coupled between this first diode and this power output end;

One the 3rd diode, its anode is coupled between this first coiling group and this power switch;

One second electric capacity, its one end is coupled to the negative terminal of the 3rd diode, and the other end is coupled to the negative terminal same place with this second diode; And

One the 4th diode, its negative terminal is coupled between this first electric capacity and this second diode, and one end coupled in series of anode and this second coiling group, the other end of this second coiling group is coupled between this second electric capacity and the 3rd diode.

2. the passive type coupling inductance soft-switching circuit of power factor corrector as claimed in claim 1, is characterized in that this power switch is a metal-oxide half field effect transistor.

3. the passive type coupling inductance soft-switching circuit of power factor corrector as claimed in claim 2, it is characterized in that this circuit has one the 3rd electric capacity further, the 3rd electric capacity is coupled between this power input end and this first inductance.

4. the passive type coupling inductance soft-switching circuit of power factor corrector as claimed in claim 3, is characterized in that this circuit has one the 4th electric capacity further, before the 4th electric capacity is coupled to this power output end.

5. the passive type coupling inductance soft-switching circuit of power factor corrector as claimed in claim 4, it is characterized in that this circuit has one the 5th diode further, its anode is coupled to this end of this first electric capacity, and negative terminal is coupled between this second electric capacity and the 3rd diode.