WO2024088139A1

WO2024088139A1 - Totem-pole bridgeless circuit, surge protection method thereof and power supply module

Info

Publication number: WO2024088139A1
Application number: PCT/CN2023/125272
Authority: WO
Inventors: 谢仁践; 刘翔
Original assignee: 深圳慧能泰半导体科技有限公司
Priority date: 2022-10-28
Filing date: 2023-10-18
Publication date: 2024-05-02
Also published as: CN115580161A

Abstract

A totem-pole bridgeless circuit. The circuit comprises a slow bridge arm unit (110) and a fast bridge arm unit (120) which are connected in parallel; an alternating-current input unit (130) connected between the midpoint of two switching transistors in the slow bridge arm unit (110) and the midpoint of two switching transistors in the fast bridge arm unit (120); a current sampling unit (140); and a surge protection unit (150). The current sampling unit (140) comprises sampling resistors respectively connected in series with the two switching transistors in the slow bridge arm unit (110). When the current sampling unit (140) collects a surge current, the circuit can control, by means of the surge protection unit (150), a first slow switching transistor (SR1), a second slow switching transistor (SR2), a first fast switching transistor (Q1) and a second fast switching transistor (Q2) to be disconnected, thereby realizing surge protection of the totem-pole bridgeless circuit. The totem-pole bridgeless circuit has a simple circuit structure and a fast response speed. Also disclosed are a totem-pole bridgeless circuit surge protection method and a power supply module.

Description

A totem pole bridgeless circuit and surge protection method thereof, and power supply module

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to a Chinese patent application filed with the China Patent Office on October 28, 2022, with application number 202211333044.7, and invention name “A totem pole bridgeless circuit, surge protection method, and power supply module”, all contents of which are incorporated by reference in this application.

Technical Field

The embodiments of the present application relate to the field of power electronics technology, and in particular to a totem pole bridgeless circuit and a surge protection method and a power supply module.

Background technique

In energy conversion systems, the conversion efficiency of power supply is an important parameter for evaluating the system. Compared with traditional power conversion circuits, bridgeless circuits can eliminate some or all diodes, thereby reducing the conduction loss of the circuit and having advantages in efficient energy conversion. As a type of bridgeless circuit, the Totem-Pole Bridgeless circuit has the advantages of simple circuit structure and high conversion efficiency, and has been increasingly widely used in recent years.

In the process of implementing the embodiments of the present application, the inventors found that there are at least the following problems in the above-mentioned related technologies: At present, due to the characteristics of the circuit structure of the totem pole bridgeless circuit, the input current will inevitably pass through the switch tube in the bridge arm unit. Limited by the impact current resistance capability of the switch tube in the bridge arm unit, when there is a large surge current generated by lightning strikes on the AC input, the switch tube in the bridge arm unit is easily damaged.

Summary of the invention

The present application provides a totem pole bridgeless circuit and a surge protection method thereof, a power supply Module.

The purpose of the embodiment of the present application is achieved through the following technical solutions:

To solve the above technical problems, in a first aspect, a totem pole bridgeless circuit is provided in an embodiment of the present application, comprising: a slow bridge arm unit, comprising a first slow switch tube and a second slow switch tube connected in series in the same direction; a fast bridge arm unit, comprising a first fast switch tube and a second fast switch tube connected in series in the same direction, and the fast bridge arm unit and the slow bridge arm unit are connected in parallel; an AC input unit, one end of which is connected between the first slow switch tube and the second slow switch tube, and the other end of which is connected between the first fast switch tube and the second fast switch tube; a current sampling unit, comprising a first sampling resistor and a second sampling resistor, the first sampling resistor is connected between the AC input unit and the second slow switch tube, and the second sampling resistor is connected between the AC input unit and the first slow switch tube; a surge protection unit, an input end of which is connected to the current sampling unit, and an output end of which is connected to the slow bridge arm unit and the fast bridge arm unit respectively, and the surge protection unit is configured to control the first slow switch tube, the second slow switch tube, the first fast switch tube and the second fast switch tube to be disconnected when a surge current is collected by the current sampling unit.

In some embodiments, the surge protection unit includes: a current limiting resistor, one end of which is connected to the current sampling unit; a hysteresis comparator, a non-phase input end of which is connected to the other end of the current limiting resistor, and the hysteresis comparator is configured to output a high-level signal when the current sampling unit collects a surge current; a low-pass filter, an input end of which is connected to the other end of the current limiting resistor, and an output end of which is connected to the inverting input end of the hysteresis comparator; a controller, an input end of which is connected to the output end of the hysteresis comparator, and an output end of which is respectively connected to the control ends of the first slow switch tube, the second slow switch tube, the first fast switch tube and the second fast switch tube, and is configured to drive the switch tubes in the slow bridge arm unit and the fast bridge arm unit to disconnect when the hysteresis comparator outputs a high-level signal.

In some embodiments, the low-pass filter includes: a filter resistor connected to the limit Between the other end of the current limiting resistor and the inverting input terminal of the hysteresis comparator; a first filter capacitor, one end of which is connected to the other end of the current limiting resistor and the other end of which is grounded; a second filter capacitor, one end of which is connected to the inverting input terminal of the hysteresis comparator and the other end of which is grounded.

In some embodiments, the input end of the surge protection unit is connected between the first sampling resistor and the second slow switching tube, and one end of the second sampling resistor connected to the first slow switching tube is grounded, or the input end of the surge protection unit is connected between the second sampling resistor and the first slow switching tube, and one end of the first sampling resistor connected to the second slow switching tube is grounded.

In some embodiments, the AC input unit also includes: an electromagnetic interference filter, whose input end is connected to the AC power supply, and whose negative output end is connected between the first sampling resistor and the second sampling resistor; an input inductor, one end of which is connected to the positive output end of the electromagnetic interference filter, and the other end of which is connected between the first fast switching tube and the second fast switching tube.

In some embodiments, the totem pole bridgeless circuit also includes: a surge bypass unit, which is connected in parallel with the fast bridge arm unit and the slow bridge arm unit, the surge bypass unit includes a first diode and a second diode connected in series in the same direction, and the positive output terminal of the electromagnetic interference filter is connected between the cathode of the first diode and the anode of the second diode.

In some embodiments, the switching of the first slow switch tube and the second slow switch tube is synchronized with the frequency of the output voltage of the AC power supply, and the reverse recovery time of the first fast switch tube and the second fast switch tube is shorter than the reverse recovery time of the first slow switch tube and the second slow switch tube.

In some embodiments, the totem pole bridgeless circuit further includes: an AC output unit, which is connected in parallel with the fast bridge arm unit and the slow bridge arm unit, wherein the AC output unit includes: an output filter capacitor, which is connected in parallel with the fast bridge arm unit and the slow bridge arm unit; and an output load, which is connected in parallel with the output filter capacitor.

To solve the above technical problems, in the second aspect, a surge protection method for a totem pole bridgeless circuit is provided in an embodiment of the present application, which is applied to the totem pole bridgeless circuit as described in the first aspect, and the method includes: collecting the current passing through the slow bridge arm unit through a current sampling unit; when the change in the collected current exceeds the threshold of the hysteresis comparator, the surge protection unit controls the switch tubes in the slow bridge arm unit and the fast bridge arm unit to disconnect.

To solve the above technical problems, in a third aspect, an embodiment of the present application provides a power supply module, including: a totem pole bridgeless circuit as described in the first aspect.

Compared with the prior art, the beneficial effects of the present invention are as follows: Different from the prior art, the embodiment of the present application provides a totem pole bridgeless circuit and a surge protection method thereof, and a power supply module. The circuit includes a slow bridge arm unit and a fast bridge arm unit connected in parallel, an AC input unit connected between the midpoints of two switch tubes in the slow bridge arm unit and the midpoints of two switch tubes in the fast bridge arm unit, a current sampling unit and a surge protection unit. The current sampling unit includes a sampling resistor connected in series with the two switch tubes in the slow bridge arm unit, respectively. When the current sampling unit collects a surge current, the circuit can control the first slow switch tube, the second slow switch tube, the first fast switch tube and the second fast switch tube to be disconnected through the surge protection unit, thereby realizing surge protection of the totem pole bridgeless circuit and the power supply module, and the circuit structure is simple and the response speed is fast.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are exemplarily described by pictures in the corresponding drawings, which do not constitute limitations on the embodiments. Elements/modules and steps with the same reference numerals in the drawings are represented as similar elements/modules and steps. Unless otherwise specified, the figures in the drawings do not constitute proportional limitations.

FIG1 is a structural block diagram of a totem pole bridgeless circuit provided in Embodiment 1 of the present application;

FIG2 is a schematic diagram of a circuit structure of a totem pole bridgeless circuit provided in Example 1 of the present application;

FIG3 is a schematic diagram of the circuit structure of another totem pole bridgeless circuit provided in Example 1 of the present application;

FIG4 is a structural block diagram of another totem pole bridgeless circuit provided in Example 1 of the present application;

FIG5( a ) is a schematic diagram of an energy storage circuit of the totem pole bridgeless circuit shown in FIG2 when the AC power input is normal and is in the positive half cycle of the AC power;

FIG5( b ) is a schematic diagram of a freewheeling circuit of the totem pole bridgeless circuit shown in FIG2 when the AC power input is normal and is in the positive half cycle of the AC power;

FIG5( c ) is a schematic diagram of the energy storage circuit of the totem pole bridgeless circuit shown in FIG2 when the AC power input is normal and is in the negative half cycle of the AC power;

FIG5( d ) is a schematic diagram of a freewheeling circuit of the totem pole bridgeless circuit shown in FIG2 when the AC power input is normal and is in the negative half cycle of the AC power;

FIG6( a ) is a schematic diagram of the surge current path of the totem pole bridgeless circuit shown in FIG2 when struck by in-phase lightning during the positive half cycle of the AC power supply;

FIG6( b ) is a schematic diagram of the surge current path of the totem pole bridgeless circuit shown in FIG2 when a reverse-phase lightning strike occurs during the positive half cycle of the AC power supply;

FIG6( c ) is a schematic diagram of the surge current path of the totem pole bridgeless circuit shown in FIG2 when struck by in-phase lightning during the negative half cycle of the AC power supply;

FIG6( d ) is a schematic diagram of the surge current path of the totem pole bridgeless circuit shown in FIG2 when a reverse-phase lightning strike occurs during the negative half cycle of the AC power supply;

FIG7( a ) is a schematic diagram of current sampling and protection waveforms under reverse-phase lightning strike during the positive half cycle of the AC power supply;

FIG7( b ) is a schematic diagram of current sampling and protection waveforms under reverse-phase lightning strike at the negative half cycle of the AC power supply;

FIG8 is a flow chart of a surge protection method for a totem pole bridgeless circuit provided in Embodiment 2 of the present application;

FIG9 is a schematic diagram of the hardware structure of a power supply module provided in Example 3 of the present application.

Description of the drawings: 100, totem pole bridgeless circuit; 110, slow bridge arm unit; 120, fast bridge arm unit; 130, AC input unit; 140, current sampling unit; 150, surge protection unit; 160, surge bypass unit; 170, AC output unit; AC, AC power supply; SR1, first slow switch tube; SR2, second slow switch tube; Q1, first fast switch tube; Q2, second fast switch tube; EMI, electromagnetic interference filter; L1, input inductor; RS1, first sampling resistor; RS2, second sampling resistor; U1, hysteresis comparator; LPF, low-pass filter; CNTLR, controller; R1, current limiting resistor; R2, filter resistor; C1, output filter capacitor; C2, first filter capacitor; C3, second filter capacitor; D1, first diode; D2, second diode; RL, output load; 10, power module.

Detailed ways

The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

It should be noted that, if there is no conflict, the various features in the embodiments of the present application can be combined with each other, all within the scope of protection of the present application. In addition, although the functional module division is performed in the device schematic diagram and the logical order is shown in the flow chart, in some cases, it may be different from the module division in the device, or the steps shown or described in the order of the flow chart. In addition, the words "first", "second", etc. used herein do not limit the data and the execution order, but only distinguish the same items or similar items with basically the same functions and effects. It should be noted that when an element is expressed as being “connected to” another element, it may be directly connected to the other element, or one or more intervening elements may exist therebetween.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

In order to solve the problem that the current totem pole bridgeless circuit cannot achieve surge protection, especially cannot protect against surge current formed by reverse lightning strike, the embodiment of the present application provides a totem pole bridgeless circuit and its surge protection method, and a power supply module. The totem pole bridgeless circuit collects the current flowing through the switch tube of the slow bridge arm unit through a current sampling unit, and controls the first slow switch tube, the second slow switch tube, the first fast switch tube and the second fast switch tube to be disconnected through the surge protection unit when the surge current is collected, so as to achieve surge protection for the totem pole bridgeless circuit and the power supply module. The circuit structure is simple and the response speed is fast. When the change in the collected current exceeds the threshold of the hysteresis comparator, it is determined that the current collected by the current sampling unit is a surge current.

Specifically, the embodiments of the present application are further described below in conjunction with the accompanying drawings.

Embodiment 1

The embodiment of the present application provides a totem pole bridgeless circuit. Please refer to FIG. 1, which shows a structural block diagram of a totem pole bridgeless circuit provided by the embodiment of the present application. The totem pole bridgeless circuit 100 includes: a slow bridge arm unit 110, a fast bridge arm unit 120, an AC input unit 130, a current sampling unit 140 and a surge protection unit 150. The totem pole bridgeless circuit 100 can determine that the current sampling unit 140 collects the current flowing through the surge protection unit 150. When the current of the slow bridge arm unit 110 is a surge current, the switch tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 are driven to be disconnected by the surge protection unit 150, thereby realizing surge protection. Specifically, please refer to FIG. 2 , which shows a circuit structure of a totem pole bridgeless circuit provided in an embodiment of the present application.

The slow bridge arm unit 110 includes a first slow switch tube SR1 and a second slow switch tube SR2 connected in series in the same direction, and the switching of the first slow switch tube SR1 and the second slow switch tube SR2 is synchronized with the frequency of the output voltage of the alternating current power source AC.

The fast bridge arm unit 120 includes a first fast switch tube Q1 and a second fast switch tube Q2 connected in series in the same direction, and the fast bridge arm unit 120 is connected in parallel with the slow bridge arm unit 110. In addition, the reverse recovery time of the first fast switch tube Q1 and the second fast switch tube Q2 is shorter than the reverse recovery time of the first slow switch tube SR1 and the second slow switch tube SR2.

In the embodiment of the present application, the "fast" and "slow" are relative speeds in reverse recovery time. The reverse recovery time of the fast switch tube is lower than the conduction voltage of the slow switch tube, and the reverse recovery time is shorter and faster. When surge current occurs and all the switches on the bridge arm need to be turned off, the connection with the output side circuit can be disconnected first to protect the electronic components on the output side. In addition, the first slow switch tube SR1 and the second slow switch tube SR2, the first fast switch tube Q1 and the second fast switch tube Q2 can be power switch devices such as thyristors, MOS tubes, IGBT tubes, and the slow switch tube and the fast switch tube can be the same type/model switch tube, or different types and models of switch tubes, which can be selected according to actual needs.

The AC input unit 130 has one end connected between the first slow switch tube SR1 and the second slow switch tube SR2, and the other end connected between the first fast switch tube Q1 and the second fast switch tube Q2. The AC input unit 130 is used to receive AC power and input the received AC power into the bridge arm unit for voltage conversion.

Specifically, please continue to refer to Figure 2, the AC input unit 130 also includes: an electromagnetic interference filter (EMI filter) EMI, whose input end is connected to the AC power supply AC, and whose negative output end is connected between the first sampling resistor RS1 and the second sampling resistor RS2; an input inductor L1, one end of which is connected to the positive output end of the electromagnetic interference filter EMI, and the other end of which is connected between the first fast switch tube Q1 and the second fast switch tube Q2.

The current sampling unit 140 includes a first sampling resistor RS1 and a second sampling resistor RS2, wherein the first sampling resistor RS1 is connected between the AC input unit 130 and the second slow switch tube SR2, and the second sampling resistor RS2 is connected between the AC input unit 130 and the first slow switch tube SR1. Compared with the traditional method of using a Hall sensor and an isolation amplifier, the embodiment of the present application can achieve fast current sampling and thus fast protection by using a resistor to collect power.

The surge protection unit 150 has an input end CS connected to the current sampling unit 140, and an output end connected to the slow bridge arm unit 110 and the fast bridge arm unit 120 respectively. The surge protection unit 150 is configured to control the first slow switch tube SR1, the second slow switch tube SR2, the first fast switch tube Q1 and the second fast switch tube Q2 to be disconnected when a surge current is collected by the current sampling unit 140.

Specifically, please continue to refer to Figure 2. The surge protection unit 150 includes: a current limiting resistor R1, a hysteresis comparator U1, a low-pass filter LPF and a controller CNTLR. Among them, the current limiting resistor R1, one end of which is connected to the current sampling unit 140; the hysteresis comparator U1, its positive phase input end is connected to the other end of the current limiting resistor R1, and the hysteresis comparator U1 is configured to output a high-level signal when the current sampling unit 140 collects a surge current; the low-pass filter LPF, its input end is connected to the other end of the current limiting resistor R1, and its output end is connected to the inverting input end of the hysteresis comparator U1; the controller CNTLR, its input end is connected to the output end of the hysteresis comparator U1, and its output end is respectively connected to the first slow switch The control ends of the switch SR1, the second slow switch SR2, the first fast switch Q1 and the second fast switch Q2 are connected, and are configured to drive the switch tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 to be disconnected when the hysteresis comparator U1 outputs a high level signal, that is, to control the first slow switch SR1, the second slow switch SR2, the first fast switch Q1 and the second fast switch Q2 to be disconnected. In the embodiment of the present application, the change rate of the current flowing through the first slow switch SR1 and the second slow switch SR2 can be detected by the hysteresis comparator U1, the reference threshold of the hysteresis comparator U1 is a non-fixed value, and the threshold is adjusted by the low-pass filter LPF, and the hysteresis comparator U1 is only triggered when the current signal input at the input terminal CS increases rapidly, which can effectively prevent false triggering. In the embodiment of the present application, the controller CNTLR is a logic control unit, which can output a low-level pulse width modulation signal to control the switching tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 to disconnect when the hysteresis comparator U1 outputs a high-level signal.

Among them, please continue to refer to Figure 2. The low-pass filter LPF is composed of a CRC filter circuit. The filter bandwidth can be adjusted according to actual needs. The low-pass filter LPF includes: a filter resistor R2, connected between the other end of the current limiting resistor R1 and the inverting input end of the hysteresis comparator U1; a first filter capacitor C2, one end of which is connected to the other end of the current limiting resistor R1, and the other end of which is grounded; a second filter capacitor C3, one end of which is connected to the inverting input end of the hysteresis comparator U1, and the other end of which is grounded.

In addition, in the example shown in FIG. 2 , the input end CS of the surge protection unit 150 is connected between the first sampling resistor RS1 and the second slow switch tube SR2, and one end of the second sampling resistor RS2 connected to the first slow switch tube SR1 is grounded; or, please refer to FIG. 3 , which shows a circuit structure of another totem pole bridgeless circuit provided in an embodiment of the present application, or the input end CS of the surge protection unit 150 is connected between the second sampling resistor RS2 and the first slow switch tube SR1, and one end of the first sampling resistor RS1 connected to the second slow switch tube SR2 is grounded.

In some embodiments, please refer to Figure 4, which shows a structural block diagram of another totem pole bridgeless circuit provided in an embodiment of the present application, the totem pole bridgeless circuit 100 also includes: a surge bypass unit 160 and an AC output unit 170, the surge bypass unit 160 is connected in parallel with the fast bridge arm unit 120 and the slow bridge arm unit 110, and the AC output unit 170 is also connected in parallel with the fast bridge arm unit 120 and the slow bridge arm unit 110.

Specifically, please continue to refer to FIG. 2 , the surge bypass unit 160 includes a first diode D1 and a second diode D2 connected in series in the same direction, and the positive output end of the electromagnetic interference filter EMI is connected between the cathode of the first diode D1 and the anode of the second diode D2.

Specifically, please continue to refer to FIG. 2 , the AC output unit 170 includes: an output filter capacitor C1 connected in parallel with the fast bridge arm unit 120 and the slow bridge arm unit 110 ; and an output load RL connected in parallel with the output filter capacitor C1 .

When the totem pole bridgeless circuit 100 provided in the embodiment of the present application works normally, please refer to FIG. 5 , which shows the energy storage circuit and the freewheeling circuit of the totem pole bridgeless circuit 100 provided in the embodiment of the present application when the alternating current is supplied through the positive and negative half cycles respectively, taking the structure of the totem pole bridgeless circuit 100 shown in FIG. 2 as an example. Specifically,

Please refer to Figure 5(a), which shows the energy storage circuit of the totem pole bridgeless circuit 100 shown in Figure 2 when the AC power supply AC input is normal and it is the positive half cycle of the AC power. At this time, the first fast switch tube Q1 is the main tube of the Boost boost circuit, the second fast switch tube Q2 is the freewheeling tube of the Boost boost circuit, the first slow switch tube SR1 remains on, and the second slow switch tube SR2 remains off; when the first fast switch tube Q1 is closed and the second fast switch tube Q2 is disconnected, the input inductor L1, the first fast switch tube Q1, and the first slow switch tube SR1 constitute an energy storage circuit, and the AC power supply AC stores energy in the input inductor L1; and the output filter capacitor C1 and the output load RL on the output side also constitute a separate current loop.

Please refer to FIG. 5( b ), which shows the freewheeling circuit of the totem pole bridgeless circuit 100 shown in FIG. 2 when the AC power supply AC input is normal and is in the positive half cycle of the AC power. At this time, the first fast The switch tube Q1 is the main tube of the Boost boost circuit, the second fast switch tube Q2 is the freewheeling tube of the Boost boost circuit, the first slow switch tube SR1 remains on, and the second slow switch tube SR2 remains off; when the second fast switch tube Q2 is closed and the first fast switch tube Q1 is disconnected, the input inductor L1, the second fast switch tube Q2, and the first slow switch tube SR1 form a freewheeling circuit, and the input inductor L1 and/or the AC power supply AC release energy to the output filter capacitor C1 and the output load RL at the load end.

Please refer to Figure 5(c), which shows the energy storage circuit of the totem pole bridgeless circuit 100 shown in Figure 2 when the AC power supply AC input is normal and it is the negative half cycle of the AC power. At this time, the second fast switch tube Q2 is the main tube of the Boost boost circuit, the first fast switch tube Q1 is the freewheeling tube of the Boost boost circuit, the first slow switch tube SR1 remains turned off, and the second slow switch tube SR2 remains turned on; when the second fast switch tube Q2 is closed and the first fast switch tube Q1 is disconnected, the second slow switch tube SR2, the second fast switch tube Q2, and the input inductor L1 constitute an energy storage circuit, and the AC power supply AC stores energy in the input inductor L1; and the output filter capacitor C1 and the output load RL on the output side also constitute a separate current loop.

Please refer to Figure 5(d), which shows the freewheeling circuit of the totem pole bridgeless circuit 100 shown in Figure 2 when the AC power supply AC input is normal and it is the negative half cycle of the AC power. At this time, the second fast switch tube Q2 is the main tube of the Boost boost circuit, the first fast switch tube Q1 is the freewheeling tube of the Boost boost circuit, the first slow switch tube SR1 remains turned off, and the second slow switch tube SR2 remains turned on; when the first fast switch tube Q1 is closed and the second fast switch tube Q2 is disconnected, the second slow switch tube SR2, the first fast switch tube Q1, and the input inductor L1 constitute a freewheeling circuit, and the input inductor L1 and/or the AC power supply AC release energy to the output filter capacitor C1 and the output load RL at the load end.

5, the current collected at the output terminal CS of the current sampling unit 140, that is, the input terminal CS of the surge protection unit 150, is negative, and the current change rate is small, the hysteresis comparator U1 will not trigger the reversal, and the controller CNTLR will not Work.

When there is a surge current caused by lightning strike on the AC input side of the totem pole bridgeless circuit 100 provided in the embodiment of the present application, please refer to FIG6, which shows the surge current paths of the same-phase and anti-phase lightning strikes generated by the totem pole bridgeless circuit 100 provided in the embodiment of the present application when the AC power is supplied through the positive and negative half cycles respectively, taking the structure of the totem pole bridgeless circuit 100 shown in FIG2 as an example. Specifically,

Please refer to FIG6(a), which shows the surge current path of the totem pole bridgeless circuit 100 shown in FIG2 when the same-phase lightning strikes the AC positive half cycle. At this time, since the surge current limits the amplitude of the surge current through the input inductor L1, the surge protection unit 150 can achieve surge protection without controlling the switch tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 to turn off. Optionally, in order to ensure further effective surge protection, the surge protection unit 150 can also be configured to control the switch tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 to turn off to achieve surge protection.

Please refer to FIG6(b), which shows the surge current path of the totem pole bridgeless circuit 100 shown in FIG2 under reverse-phase lightning strike at the positive half cycle of the AC power supply AC. Since the surge current does not pass through the input inductor L1, the surge current has a large amplitude and is easy to damage the first slow switch tube SR1. Please also refer to FIG7(a), which shows the current sampling and protection waveform under reverse-phase lightning strike at the positive half cycle of the AC power supply AC. When a reverse-phase lightning strike occurs in the positive half cycle, the current I_SR1 flowing through the first sampling resistor RS1 and the first slow switch tube SR1 increases sharply, and the current collected at the output terminal CS of the current sampling unit 140, that is, the input terminal CS of the surge protection unit 150, also increases sharply synchronously, and quickly changes from a negative level in a normal state to a positive level. The current change rate is large, causing the hysteresis comparator U1 to reverse, and the output terminal Trig of the hysteresis comparator U1 outputs a high-level signal to drive the controller CNTLR to output a low-level pulse width modulation (PWM) signal to the control terminals of the first slow switch tube SR1 and the first fast switch tube Q1, and quickly turns off the first slow switch tube SR1 and the first fast switch tube Q1 to achieve surge protection.

Please refer to FIG6(c), which shows the surge current path of the totem pole bridgeless circuit 100 shown in FIG2 when the same-phase lightning strike occurs at the negative half cycle of the AC power supply AC. At this time, since the surge current limits the amplitude of the surge current through the input inductor L1, the surge protection unit 150 can achieve surge protection without controlling the switch tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 to turn off. Optionally, in order to ensure further effective surge protection, the surge protection unit 150 can also be configured to control the switch tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 to turn off to achieve surge protection.

Please refer to Figure 6(d), which shows the surge current path of the totem pole bridgeless circuit 100 shown in Figure 2 during the reverse lightning strike at the negative half-cycle of the AC power supply AC. At this time, since the surge current does not pass through the input inductor L1, the surge current amplitude is large and it is easy to damage the second slow switch tube SR2. At this time, the surge protection unit 150 needs to be configured to control the switch tubes in the slow bridge arm unit 110 and the fast bridge arm unit 120 to turn off to achieve surge protection.

Please refer to Figure 6(d), which shows the surge current path of the totem pole bridgeless circuit 100 shown in Figure 2 under reverse lightning strike at the negative half cycle of the AC power supply AC. Since the surge current does not pass through the input inductor L1, the surge current has a large amplitude and is easy to damage the first slow switch tube SR1. Please also refer to Figure 7(b), which shows the current sampling and protection waveform under reverse lightning strike at the negative half cycle of the AC power supply AC. When a negative half-cycle reverse-phase lightning strike occurs, the current I_SR2 flowing through the second sampling resistor RS2 and the second slow switch tube SR2 increases dramatically, and the current collected at the output terminal CS of the current sampling unit 140, that is, the input terminal CS of the surge protection unit 150, also increases dramatically synchronously, and quickly changes from a negative level in a normal state to a positive level. The current change rate is large, causing the hysteresis comparator U1 to reverse, and the output terminal Trig of the hysteresis comparator U1 outputs a high-level signal to drive the controller CNTLR to output a low-level pulse width modulation (PWM) signal to the control terminals of the second slow switch tube SR2 and the second fast switch tube Q2, and quickly turns off the second slow switch tube SR2 and the second fast switch tube Q2 to achieve surge protection.

Embodiment 2

The embodiment of the present application provides a surge protection method for a totem pole bridgeless circuit. The surge protection method is applied to the totem pole bridgeless circuit as described in the first embodiment. Please refer to FIG8 , which shows a surge protection method provided by the embodiment of the present application, and the method includes but is not limited to the following steps:

Step S10: collecting the current passing through the slow bridge arm unit through the current sampling unit;

Specifically, in the embodiments of the present application, referring to Embodiment 1, it can be known that the current passing through the switch tube of the slow bridge arm unit can be quickly collected by the current sampling unit, so that when a surge current occurs, the surge current is collected and the collected current is output to the surge protection unit to achieve rapid surge protection.

Step S20: When the acquired current variation exceeds the threshold of the hysteresis comparator, the surge protection unit controls the switch tubes in the slow bridge arm unit and the fast bridge arm unit to be disconnected.

In the embodiment of the present application, it is not difficult to see from the figures of the above embodiment 1 Figure 6 that when there is a reverse-phase lightning strike, the first slow switch tube or the second slow switch tube is easily burned. Therefore, when the rate of change of the current collected by the current sampling unit exceeds the threshold of the hysteresis comparator, the protection is quickly triggered to close the corresponding switch tubes, that is, the first slow switch tube and the first fast switch tube, or the second slow switch tube and the second fast switch tube, to achieve surge protection.

Embodiment 3

An embodiment of the present application provides a power supply module. Please refer to Figure 9, which shows the hardware structure of a power supply module provided by an embodiment of the present application. The power supply module 10 includes: a totem pole bridgeless circuit 100 as described in Example 1.

In an energy conversion system, such as a power module 10, the totem pole bridgeless circuit 100 provided in the first embodiment of the present application can be used to realize the protection of the AC power supply when the same-phase lightning strike and the opposite-phase lightning strike occur. protection to achieve surge protection.

In an embodiment of the present application, a totem pole bridgeless circuit and a surge protection method and a power supply module are provided. The circuit includes a slow bridge arm unit and a fast bridge arm unit connected in parallel, an AC input unit connected between the midpoints of two switch tubes in the slow bridge arm unit and the midpoints of two switch tubes in the fast bridge arm unit, a current sampling unit and a surge protection unit. The current sampling unit includes a sampling resistor connected in series with the two switch tubes in the slow bridge arm unit, respectively. When the current sampling unit collects a surge current, the circuit can control the first slow switch tube, the second slow switch tube, the first fast switch tube and the second fast switch tube to be disconnected through the surge protection unit, thereby realizing surge protection for the totem pole bridgeless circuit and the power supply module, and the circuit structure is simple and the response speed is fast.

It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, and may be located in one place or distributed over multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Through the description of the above implementation methods, a person of ordinary skill in the art can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course, can also be implemented by hardware. A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, and are not intended to To limit it; under the idea of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity; although the present invention is described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to make equivalent replacements for some of the technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

A totem pole bridgeless circuit, characterized by comprising:

The slow bridge arm unit comprises a first slow switch tube and a second slow switch tube connected in series in the same direction;

A fast bridge arm unit comprises a first fast switch tube and a second fast switch tube connected in series in the same direction, and the fast bridge arm unit and the slow bridge arm unit are connected in parallel;

an AC input unit, one end of which is connected between the first slow switch tube and the second slow switch tube, and the other end of which is connected between the first fast switch tube and the second fast switch tube;

A current sampling unit, comprising a first sampling resistor and a second sampling resistor, wherein the first sampling resistor is connected between the AC input unit and the second slow switching tube, and the second sampling resistor is connected between the AC input unit and the first slow switching tube;

A surge protection unit, whose input end is connected to the current sampling unit, and whose output end is respectively connected to the slow bridge arm unit and the fast bridge arm unit, wherein the surge protection unit is configured to control the first slow switch tube, the second slow switch tube, the first fast switch tube and the second fast switch tube to be disconnected when a surge current is collected by the current sampling unit.
The totem pole bridgeless circuit according to claim 1, characterized in that the surge protection unit comprises:

A current limiting resistor, one end of which is connected to the current sampling unit;

A hysteresis comparator, whose non-phase input terminal is connected to the other end of the current limiting resistor, and the hysteresis comparator is configured to output a high level signal when the current sampling unit collects the surge current;

A low-pass filter, whose input end is connected to the other end of the current-limiting resistor, and whose output end is connected to the inverting input end of the hysteresis comparator;

A controller, whose input end is connected to the output end of the hysteresis comparator, and whose output end is respectively connected to the control ends of the first slow switch tube, the second slow switch tube, the first fast switch tube and the second fast switch tube, and is configured to drive the switch tubes in the slow bridge arm unit and the fast bridge arm unit to disconnect when the hysteresis comparator outputs a high-level signal.
The totem pole bridgeless circuit according to claim 2, characterized in that the low-pass filter comprises:

A filter resistor connected between the other end of the current limiting resistor and the inverting input end of the hysteresis comparator;

A first filter capacitor, one end of which is connected to the other end of the current limiting resistor, and the other end of which is grounded;

A second filter capacitor has one end connected to the inverting input end of the hysteresis comparator and the other end grounded.
The totem pole bridgeless circuit according to claim 2 is characterized in that:

The input end of the surge protection unit is connected between the first sampling resistor and the second slow switch tube, and one end of the second sampling resistor connected to the first slow switch tube is grounded.

or,

The input end of the surge protection unit is connected between the second sampling resistor and the first slow switch tube, and one end of the first sampling resistor connected to the second slow switch tube is grounded.
The totem pole bridgeless circuit according to any one of claims 1 to 4, characterized in that the AC input unit further comprises:

An electromagnetic interference filter, whose input end is connected to an AC power supply, and whose negative output end is connected between the first sampling resistor and the second sampling resistor;

An input inductor, one end of which is connected to the positive output end of the electromagnetic interference filter, and the other end of which is connected between the first fast switch tube and the second fast switch tube.
The totem pole bridgeless circuit according to claim 5, characterized in that the totem pole bridgeless circuit further comprises:

A surge bypass unit is connected in parallel with the fast bridge arm unit and the slow bridge arm unit. The surge bypass unit includes a first diode and a second diode connected in series in the same direction. The positive output end of the electromagnetic interference filter is connected between the cathode of the first diode and the anode of the second diode.
The totem pole bridgeless circuit according to claim 5 is characterized in that:

The switching of the first slow switching tube and the second slow switching tube is synchronized with the frequency of the output voltage of the AC power supply.

The reverse recovery time of the first fast switch tube and the second fast switch tube is shorter than the reverse recovery time of the first slow switch tube and the second slow switch tube.
The totem pole bridgeless circuit according to claim 7, characterized in that the totem pole bridgeless circuit further comprises:

An AC output unit, which is connected in parallel with the fast bridge arm unit and the slow bridge arm unit, wherein the AC output unit comprises:

An output filter capacitor connected in parallel with the fast bridge arm unit and the slow bridge arm unit;

An output load is connected in parallel with the output filter capacitor.
A surge protection method for a totem pole bridgeless circuit, characterized in that it is applied to the totem pole bridgeless circuit according to any one of claims 1 to 8, and the method comprises:

The current passing through the slow bridge arm unit is collected by a current sampling unit;

When the variation of the collected current exceeds the threshold of the hysteresis comparator, the surge protection unit controls the switch tubes in the slow bridge arm unit and the fast bridge arm unit to be disconnected.
A power supply module, characterized by comprising: a totem pole bridgeless circuit as described in any one of claims 1-8.