TWI868583B - Totem-pole power factor corrector with zero-voltage switching - Google Patents

Abstract

A Totem-pole power factor corrector with zero-voltage switching is used to receive an input power source and convert the input power source into an output power source. The Totem-pole power factor corrector includes an input inductor, a fast-switching leg, a slow-switching leg, a resonant tank, and an output capacitor. A first end of the input inductor receives the input power source. The fast-switching leg includes a fast-switching upper switch and a fast-switching lower switch, and the fast-switching upper switch and the fast-switching lower switch are commonly coupled at a first middle node. The slow-switching leg is coupled in parallel to the fast-switching leg, and the slow-switching leg includes a slow-switching upper and a slow-switching lower switch. The resonant tank includes a resonant inductor and at least one resonant capacitor. A first end of the resonant inductor is coupled to the first middle node, and a second end of the resonant inductor is coupled to the at least one capacitor. The output capacitor is coupled in parallel to the fast-switching leg to provide the output power source.

Description

Totem pole power factor corrector with zero voltage switching

The present invention relates to a totem pole power factor corrector, in particular to a totem pole power factor corrector with zero voltage switching.

For Totem-pole PFC (TPPFC), the power density is usually increased by increasing the switching frequency. However, the traditional approach operates in continuous conduction mode (CCM), because the heat generated by hard switching increases with the increase of switching frequency, so frequency reduction must be used to reduce the generated heat. However, although the reduction of switching frequency can reduce the generation of heat, it cannot achieve the effect of reducing the size of magnetic components. Therefore, the critical conduction mode (CRM) operation mode was proposed, which has the characteristics of zero-voltage switching (ZVS), which increases the operating frequency and improves efficiency. However, this operation mode is accompanied by the following deficiencies:

1. Dramatic frequency changes make control more difficult and the total input harmonic distortion (THD) is higher.

2. It has both high-frequency ripple and low-frequency main power components, so it is not easy to design the filtering function of the magnetic components.

3. The peak current under CRM operation is twice that under traditional CCM, and the volume of magnetic components needs to be larger.

4. Due to the large input ripple, if only a single-arm switch is used, a larger electromagnetic interference inductor (EMI choke) is required, which will lose the size advantage. Therefore, two-phase interleave operation is often used to solve this problem. However, this increases the cost and control complexity, resulting in the dilemma of using multiple switches for low power.

Therefore, how to design a zero-voltage switching totem pole power factor corrector, which can maintain continuous conduction mode (CCM) operation by adding a set of LC resonant tanks to the circuit structure of the existing totem pole power factor corrector (TPPFC) to solve the shortcomings of the existing technology, is an important topic studied by the inventor of this case.

The purpose of the present invention is to provide a zero-voltage switching totem pole power factor corrector to solve the problems of the prior art.

To achieve the above-mentioned purpose, the present invention proposes a zero-voltage switching totem pole power factor corrector for receiving input power and converting the input power into output power. The totem pole power factor corrector includes an input inductor, a fast switching bridge arm, a slow switching bridge arm, a resonant tank, and an output capacitor. The first end of the input inductor receives the input power. The fast switching bridge arm includes a fast upper switch and a fast lower switch, and the fast upper switch and the fast lower switch are connected to a first midpoint. The slow switching bridge arm is coupled in parallel to the fast switching bridge arm, and the slow switching bridge arm includes a slow upper switch and a slow lower switch. The resonant tank includes a resonant inductor and at least a resonant capacitor. The first end of the resonant inductor is coupled to the first midpoint, and the second end of the resonant inductor is coupled to at least one resonant capacitor. The output capacitor is coupled in parallel with the fast switching bridge arm to provide output power.

In one embodiment, the number of at least one resonant capacitor is one. The first end of the resonant capacitor is coupled to the second end of the resonant inductor, and the second end of the resonant capacitor is coupled to the fast upper switch and the slow upper switch.

In one embodiment, the number of at least one resonant capacitor is one. The first end of the resonant capacitor is coupled to the second end of the resonant inductor, and the second end of the resonant capacitor is coupled to the fast down switch and the slow down switch.

In one embodiment, the number of at least one resonant capacitor is two, namely a first resonant capacitor and a second resonant capacitor. The first end of the first resonant capacitor and the first end of the second resonant capacitor are coupled to the second end of the resonant inductor, the second end of the first resonant capacitor is coupled to the fast down switch and the slow down switch, and the second end of the second resonant capacitor is coupled to the fast up switch and the slow up switch.

In one embodiment, the first end of the fast upper switch and the first end of the fast lower switch are connected to the first midpoint; the first end of the slow upper switch and the first end of the slow lower switch are connected to the input power supply. The second end of the fast upper switch is coupled to the second end of the slow upper switch, and the second end of the fast lower switch is coupled to the second end of the slow lower switch.

In one embodiment, the input inductor and the resonant inductor are an integrated coupling structure.

In one embodiment, the totem pole power factor corrector is an N-phase operation. The N-phase totem pole power factor corrector includes: N sets of input inductors, N sets of fast switching bridge arms, N sets of resonant tanks, and a set of slow switching bridge arms and a set of output capacitors.

In one embodiment, the input inductance of each phase is coupled to the resonant inductance of the corresponding resonant tank.

In one embodiment, the two resonant inductors between the two phases are cross-coupled.

The proposed zero-voltage switching totem column power factor corrector can achieve the following features and advantages: 1. The addition of an LC resonant tank enables the full-switch zero-voltage switching function, reduces switching losses, and improves power conversion efficiency. 2. The addition of an LC resonant tank can accelerate the release of the energy stored in the parasitic capacitance of the switch, and can suppress the surge during switch switching to protect the switch. 3. It has very small input inductor current ripple, so a smaller electromagnetic interference (EMI) level can be selected. 4. Through the resonance of the internal resonant tank, the parasitic capacitance of the switch to be turned on can be discharged during the switch dead time, so that it can achieve zero-voltage conduction. 5. Zero-voltage switching reduces the heat dissipation requirements of the switch module. 6. Zero voltage switching increases the switching frequency and reduces the size of magnetic components. 7. If coupled inductors are used to integrate the resonant inductor and the input inductor, the advantage of magnetic flux cancellation can be obtained, which can improve efficiency, integration and power density. 8. With coupled inductors, there is no additional magnetic component occupying volume, which will not increase costs.

In order to further understand the technology, means and effects adopted by the present invention to achieve the intended purpose, please refer to the following detailed description and attached figures of the present invention. It is believed that the purpose, features and characteristics of the present invention can be understood in depth and concretely. However, the attached figures are only provided for reference and explanation, and are not used to limit the present invention.

L,Lboost,nL: input inductance

11: Quick switch bridge arm

12: Slow switching bridge arm

13: Resonance groove

Co: output capacitance

N1: First midpoint

S ₁ ,nS ₁ : Fast switch down

S ₂ ,nS ₂ : Fast on/off switch

M ₁ : Slow down switch

M ₂ : Slow on/off

L _r ,nL _r : resonant inductance

C _r ,nC _r : resonant capacitance

C _r1 : First resonant capacitor

C _r2 : Second resonant capacitor

Vin: Input power

Vo: output power

FIG. 1A is a circuit diagram of the first embodiment of the present invention's zero-voltage switching totem pole power factor corrector.

FIG1B is a circuit diagram of the second embodiment of the present invention's zero-voltage switching totem pole power factor corrector.

FIG. 1C is a circuit diagram of the third embodiment of the present invention's zero-voltage switching totem pole power factor corrector.

Figure 2 is a circuit block diagram of the multi-phase parallel structure of the zero-voltage switching totem pole power factor corrector of the present invention.

FIG3A is a circuit diagram of the first embodiment of the inductive coupling of the multi-phase parallel structure of the zero-voltage switching totem pole power factor corrector of the present invention.

FIG3B is a circuit diagram of the second embodiment of the inductive coupling of the multi-phase parallel structure of the zero-voltage switching totem pole power factor corrector of the present invention.

Figure 4 is a circuit diagram of an inductive coupling embodiment of the zero-voltage switching totem pole power factor corrector of the present invention under a single-phase architecture.

The technical content and detailed description of the present invention are as follows, along with the accompanying drawings.

Please refer to FIG. 1A to FIG. 1C, which are circuit diagrams of the first embodiment, the second embodiment and the third embodiment of the zero-voltage switching totem pole power factor corrector of the present invention. The zero-voltage switching totem pole power factor corrector (hereinafter referred to as the totem pole power factor corrector) is used to receive an input power Vin and convert the input power Vin into an output power Vo. In this embodiment, the input power Vin is an AC power source, and the converted output power Vo is a DC power source.

The totem column power factor corrector includes an input inductor L, a fast switching bridge arm 11, a slow switching bridge arm 12, a resonant tank 13 and an output capacitor Co.

The input inductor L has a first end and a second end, and the first end of the input inductor L receives the input power Vin, i.e., the AC power. The fast switching bridge arm 11 includes a fast upper switch _S2 and a fast lower switch _S1 , and the fast upper switch _S2 and the fast lower switch _S1 are connected to the first midpoint N1. In this embodiment, the fast switching bridge arm 11 is coupled to the AC input power Vin through the input inductor L. The slow switching bridge arm 12 is coupled to the fast switching bridge arm 11 in parallel. The slow switching bridge arm 12 includes a slow upper switch _M2 and a slow lower switch _M1 . In this embodiment, the slow switching bridge arm 12 is directly coupled to the AC input power Vin and is controlled by the mains frequency (i.e., the frequency of the AC input power Vin).

The first end of the fast upper switch _S2 and the first end of the fast lower switch _S1 are connected to the first midpoint N1. The first end of the slow upper switch _M2 and the first end of the slow lower switch _M1 are connected to the input power Vin. The second end of the fast upper switch _S2 is coupled to the second end of the slow upper switch _M2 , and the second end of the fast lower switch _S1 is coupled to the second end of the slow lower switch _M1 . Therefore, a dual-level architecture is formed through this circuit topology.

The resonant tank 13 includes a resonant inductor _Lr and at least one resonant capacitor _Cr , _Cr1 , _Cr2 . A first end of the resonant inductor _Lr is coupled to the first midpoint N1, and a second end of the resonant inductor _Lr is coupled to at least one resonant capacitor _Cr , _Cr1 , _Cr2 . An output capacitor Co is coupled in parallel to the fast switch bridge arm 11 to provide an output power Vo.

In the first embodiment shown in FIG. 1A , the number of the at least one resonant capacitor is one. A first end of the resonant capacitor _Cr is coupled to a second end of the resonant inductor _Lr , and a second end of the resonant capacitor _Cr is coupled to the fast switch _S2 and the slow switch _M2 .

In the second embodiment shown in FIG. 1B , the number of the at least one resonant capacitor is one. A first end of the resonant capacitor _Cr is coupled to a second end of the resonant inductor _Lr , and a second end of the resonant capacitor _Cr is coupled to the fast down switch _S1 and the slow down switch _M1 .

In the third embodiment shown in FIG. 1C , the number of at least one resonant capacitor is two, namely a first resonant capacitor _Cr1 and a second resonant capacitor _Cr2 . A first end of the first resonant capacitor _Cr1 and a first end of the second resonant capacitor _Cr2 are coupled to a second end of the resonant inductor _Lr . A second end of the first resonant capacitor _Cr1 is coupled to a fast down switch _S1 and a slow down switch _M1 . A second end of the second resonant capacitor _Cr2 is coupled to a fast up switch _S2 and a slow up switch _M2 .

It is worth mentioning that in the third embodiment shown in FIG. 1C , since two resonant capacitors C _r1 , C _r2 are used, the voltage across each resonant capacitor C _r1 , C _r2 can be relatively low, about half of the voltage across a single resonant capacitor in FIG. 1A and FIG. 1B . Therefore, the capacitance value selected for each resonant capacitor C _r1 , C _r2 can be relatively small. In one embodiment, the capacitance value of each resonant capacitor C _r1 , C _r2 is the same and half of the original capacitance. Therefore, the current stress of each resonant capacitor C _r1 , C _r2 is only half of that of a single resonant capacitor.

Furthermore, in the circuit structure of the third embodiment, the two resonant capacitors C _r1 , C _r2 provide two current paths for the inductor current (ie, the current flowing through the resonant inductor L _r ), thereby increasing the service life of each resonant capacitor C _r1 , C _r2 .

In summary, the present invention adds an LC resonant tank and a power inductor (i.e., input inductor L) so that the fast upper switch _S2 and the fast lower switch _S1 of the fast switching bridge arm 11 have a zero-voltage switching effect. Its characteristic is that under the TPPFC (Totem Pole Power Factor Corrector) architecture, a resonant inductor _Lr is connected to the junction of the half-bridge switch and the input inductor L, and then connected in series with a resonant capacitor _Cr to the positive or negative end of the DC output capacitor Co, or connected with two resonant capacitors _Cr1 and _Cr2 to the positive and negative ends of the output capacitor Co.

Please refer to FIG2, which is a circuit block diagram of a multi-phase parallel architecture of a zero-voltage switching totem column power factor corrector of the present invention. Different from FIG1A to FIG1C, the zero-voltage switching totem column power factor corrector of the present invention is applied to a single-phase architecture, and the present invention can also realize the multi-phase parallel architecture shown in FIG2. Specifically, as shown in FIG2, when the totem column power factor corrector is operated in N phases, the N-phase totem column power factor corrector includes N sets of input inductors L, N sets of fast switching bridge arms 11, N sets of resonant slots 13, and a set of slow switching bridge arms 12 and a set of output capacitors Co. As shown in FIG2 , nL represents the Nth group of input inductors L, nS ₁ represents the Nth group of fast lower switches of the fast switching bridge arm 11, nS ₂ represents the Nth group of fast upper switches of the fast switching bridge arm 11, nL _r represents the Nth group of resonant inductors, and nC _r represents the Nth group of resonant capacitors. In addition, the output of the Nth group of circuit architecture shown in FIG2 is coupled to the two ends of the output capacitor Co (respectively represented by B+ and B-). Thus, through the multi-phase parallel architecture, staggered phase control can be used to reduce the ripple components of the input current because they cancel each other out.

Under the multi-phase parallel structure shown in FIG2 , there are different types of inductive coupling. As shown in FIG3A , it is a circuit diagram of the first embodiment of the inductive coupling under the multi-phase parallel structure of the zero-voltage switching totem pole power factor corrector of the present invention. Specifically, the input inductance Lboost of each phase is coupled with the resonant inductance _Lr of the corresponding resonant slot 13. Alternatively, as shown in FIG3B , it is a circuit diagram of the second embodiment of the inductive coupling under the multi-phase parallel structure of the zero-voltage switching totem pole power factor corrector of the present invention. Specifically, the two resonant inductances _Lr between the two phases are cross-coupled.

Please refer to FIG4, which is a circuit diagram of an inductive coupling embodiment of the zero-voltage switching totem pole power factor corrector of the present invention under a single-phase architecture. In this case, the input inductor L and the resonant inductor _Lr can be two separate inductors, two sets of coils (wound on two different cores), or the input inductor L and the resonant inductor _Lr can be an integrated coupling structure, that is, the input inductor L and the resonant inductor _Lr can share a core to achieve an integrated architecture with a shared coupling magnetic path, as shown in FIG4.

In summary, the invention provides a zero-voltage switching totem pole power factor corrector, which can maintain continuous conduction mode (CCM) operation by adding a set of LC resonant tanks to the circuit structure of the existing totem pole power factor corrector (TPPFC), thus solving the defects of the existing technology.

In summary, the present invention has the following features and advantages:

1. Adding LC resonance tank enables full switch zero voltage switching function, reduces switching loss, and improves power conversion efficiency.

2. Adding an LC resonant tank can accelerate the release of the energy stored in the parasitic capacitance of the switch and suppress the surge during switch switching to protect the switch.

3. It has very small input inductor current ripple, so a smaller EMI level can be selected.

4. Through the resonance of the internal resonant tank, the parasitic capacitance of the switch to be turned on can be discharged during the dead time of the switch, so that it can be turned on at zero voltage.

5. Zero voltage switching reduces the heat dissipation requirements of the switch module.

6. Zero voltage switching increases the switching frequency and reduces the volume of magnetic components.

7. If coupled inductors are used to integrate the resonant inductor and the input inductor, the advantage of magnetic flux cancellation can be obtained, which can improve efficiency, while also improving integration and power density.

8. When used with coupled inductors, there is no need for additional magnetic components to occupy volume, and the cost will not be increased.

The above is only a detailed description and diagram of the preferred specific embodiment of the present invention, but the features of the present invention are not limited thereto, and are not used to limit the present invention. The entire scope of the present invention shall be subject to the following patent application scope. All embodiments that conform to the spirit of the patent application scope of the present invention and its similar variations shall be included in the scope of the present invention. Any changes or modifications that can be easily thought of by anyone familiar with the art within the field of the present invention can be covered by the following patent scope of this case.

L: Input inductance

11: Quick switch bridge arm

12: Slow switching bridge arm

13: Resonance groove

Co: output capacitance

N1: First midpoint

S ₁ : Quick switch down

S ₂ : Quick on/off switch

M ₁ : Slow down switch

M ₂ : Slow on/off

L _r : Resonant inductance

C _r : Resonance Capacitor

Vin: Input power

Vo: output power

Claims (9)

A zero-voltage switching totem pole power factor corrector is used to receive an input power source and convert the input power source into an output power source. The totem pole power factor corrector includes: an input inductor, a first end of which receives the input power source; a fast switching bridge arm, including a fast upper switch and a fast lower switch, and the fast upper switch and the fast lower switch are connected to a first midpoint; a slow A fast switching bridge arm is coupled in parallel with the fast switching bridge arm, the slow switching bridge arm includes a slow upper switch and a slow lower switch; a resonant tank includes a resonant inductor and at least one resonant capacitor, a first end of the resonant inductor is coupled to the first midpoint, and a second end of the resonant inductor is coupled to the at least one resonant capacitor; and an output capacitor is coupled in parallel with the fast switching bridge arm to provide the output power. A zero-voltage switching totem pole power factor corrector as described in claim 1, wherein the number of the at least one resonant capacitor is one; a first end of the resonant capacitor is coupled to the second end of the resonant inductor, and a second end of the resonant capacitor is coupled to the fast upper switch and the slow upper switch. A zero-voltage switching totem pole power factor corrector as described in claim 1, wherein the number of the at least one resonant capacitor is one; a first end of the resonant capacitor is coupled to the second end of the resonant inductor, and a second end of the resonant capacitor is coupled to the fast down switch and the slow down switch. The zero-voltage switching totem pole power factor corrector as described in claim 1, wherein the at least one resonant capacitor is two in number, namely a first resonant capacitor and a second resonant capacitor; a first end of the first resonant capacitor and a first end of the second resonant capacitor are coupled to the second end of the resonant inductor, a second end of the first resonant capacitor is coupled to the fast down switch and the slow down switch, and a second end of the second resonant capacitor is coupled to the fast up switch and the slow up switch. A zero-voltage switching totem pole power factor corrector as described in claim 1, wherein a first end of the fast upper switch and a first end of the fast lower switch are connected to the first midpoint; a first end of the slow upper switch and a first end of the slow lower switch are connected to the input power source; a second end of the fast upper switch is coupled to a second end of the slow upper switch, and a second end of the fast lower switch is coupled to a second end of the slow lower switch. A zero-voltage switching totem pole power factor corrector as described in claim 1, wherein the input inductor and the resonant inductor are an integrated coupling structure. A zero-voltage switching totem pole power factor corrector as described in claim 1, wherein the totem pole power factor corrector is an N-phase operation; the N-phase totem pole power factor corrector includes: N sets of input inductors, N sets of fast switching bridge arms, N sets of resonant tanks, and one set of slow switching bridge arms and one set of output capacitors. A zero-voltage switching totem pole power factor corrector as described in claim 7, wherein the input inductor of each phase is coupled to the resonant inductor of the corresponding resonant tank. A totem pole power factor corrector with zero voltage switching as described in claim 7, wherein the two resonant inductors between the two phases are cross-coupled.

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