CN116015045A - PFC circuit and related equipment - Google Patents

Abstract

The embodiment of the application provides a PFC circuit and related equipment, which are used for improving the flexibility of upper and lower bridge arm switches. The PFC circuit comprises a first upper bridge arm circuit, a first lower bridge arm circuit and a first capacitor. The first upper bridge arm circuit comprises a first driver, a first auxiliary power supply, a first switch tube and a second capacitor, wherein the first switch tube comprises a control end, an input end and an output end, the input end is coupled with the alternating current power supply, the output end is connected with the first capacitor, the control end is connected with the first driver, one end of the second capacitor is connected with the first driver, the other end of the second capacitor is connected with the input end, the low level of the first auxiliary power supply is connected with the input end, and the high level of the first auxiliary power supply is connected with the second capacitor. By adding the first auxiliary power supply into the first bridge arm circuit, the start and stop of the PFC circuit are not influenced by the charge quantity of the first capacitor, and the power can be turned on and off at any time, so that the flexibility of the upper and lower bridge arm switching tubes is improved.

Description

PFC circuit and related equipment

Technical Field

The embodiment of the application relates to the field of power conversion, in particular to a PFC circuit and related equipment.

Background

Since output power type requirements of power sources may be different for electronic devices such as servers, user terminals, network devices, etc., in a power system, there are power conversion circuits that convert power sources, for example, power conversion circuits including a power factor correction (power factor correction, PFC) circuit and a direct current-to-direct current (direct current direct current, DCDC) circuit. In the application scene of PFC, in order to realize high efficiency and miniaturization of a server power supply, totem pole bridgeless PFC is utilized to realize electric energy conversion of a power supply module, in the totem pole bridgeless PFC, a half-bridge loop comprising upper and lower bridge arm switching tubes is adopted, a floating power supply is needed when the upper bridge arm switching tubes are driven, and in common scenes, a bootstrap capacitor is adopted to provide the floating power supply for the upper bridge arm switching tubes.

The working effect of the bootstrap capacitor is limited by the self electric quantity of the bootstrap capacitor and the condition of charging the bootstrap capacitor in a loop, flexible switching of the upper and lower bridge arm switching tubes cannot be realized by effectively utilizing the bootstrap capacitor, and how to realize flexible switching of the upper and lower bridge arm switching tubes becomes a problem to be solved by a technical staff.

Disclosure of Invention

The embodiment of the application provides a PFC circuit and related equipment, which are used for improving the flexibility of upper and lower bridge arm switching tubes.

A first aspect of the present embodiments provides a power factor correction (power factor correction, PFC) circuit including a first upper leg circuit, a first lower leg circuit, and a first capacitor; the first capacitor is connected between the first upper bridge arm circuit and the first lower bridge arm circuit, the first upper bridge arm and the first lower bridge arm are connected with an alternating current power supply, and the first upper bridge arm circuit and the first lower bridge arm circuit work cooperatively to change alternating current output by the alternating current power supply into direct current; the first upper bridge arm circuit comprises a first driver, a first auxiliary power supply, a first switch tube and a second capacitor, wherein the first switch tube comprises a control end, an input end and an output end, the input end is coupled with the alternating current power supply, the output end is connected with the first capacitor, the control end is connected with the first driver, the first driver is used for driving a switch of the first switch tube, one end of the second capacitor is connected with the first driver, the other end of the second capacitor is connected with the input end, the low level of the first auxiliary power supply is connected to the input end, and the high level of the first auxiliary power supply is connected to the second capacitor and is used for providing electric energy for the first driver.

In the embodiment of the application, the PFC circuit includes a first upper bridge arm circuit, a first lower bridge arm circuit, and a first capacitor, where the first capacitor is connected between the first upper bridge arm circuit and the first lower bridge arm circuit, and by adding a first driver and a first driver to the first upper bridge arm circuit, both the first upper bridge arm and the first lower bridge arm are connected with an ac power supply, and the first upper bridge arm circuit and the first lower bridge arm circuit work cooperatively to change an ac current output by the ac power supply into a dc current. The first upper bridge arm circuit comprises a first driver, a first auxiliary power supply, a first switch tube and a second capacitor, wherein the first switch tube comprises a control end, an input end and an output end, the input end is coupled with the alternating current power supply, the output end is connected with the first capacitor, the control end is connected with the first driver, the first driver is used for driving a switch of the first switch tube, one end of the second capacitor is connected with the first driver, the other end of the second capacitor is connected with the input end, the low level of the first auxiliary power supply is connected with the input end, and the high level of the first auxiliary power supply is connected with the second capacitor and used for providing electric energy for the first driver. By adding the first auxiliary power supply into the first bridge arm circuit, the start and stop of the PFC circuit are not influenced by the charge quantity of the first capacitor, and the power can be turned on and off at any time, so that the flexibility of the upper and lower bridge arm switching tubes is improved.

In a possible implementation manner of the first aspect, the first upper bridge arm circuit further includes: a first diode; and one end of the first diode is connected with the second capacitor and the driver, and the other end of the first diode is connected with the output end of the first auxiliary power supply and is used for preventing current from flowing back to the output end of the first auxiliary power supply.

In this embodiment of the application, through addding the first diode that is connected with the output of second electric capacity, driver and auxiliary power supply, prevent that the electric current from flowing backward to the output of first auxiliary power supply. Through addding first diode, prevent that the electric current from flowing backward, promoted the security of scheme.

In a possible implementation manner of the first aspect, the first upper bridge arm circuit further includes: a first power supply and a second diode; a second diode coupled to the first driver, the second capacitor, and the first power supply for preventing current from flowing back to the first power supply; the first power supply is coupled with the second capacitor and is used for providing electric energy for the second capacitor when the input voltage of the first switch tube is smaller than the output voltage of the first power supply. In the embodiment of the application, a second diode and a first power supply for preventing current from flowing back to the power supply are added to the PFC circuit; the first power supply is coupled with the second capacitor, and is used for providing electric energy for the second capacitor when the input voltage of the first switching tube is smaller than the output voltage of the first power supply, and the first power supply and the first auxiliary power supply power for the first driver together, so that the condition that long-term stable power supply is needed when only the first auxiliary power supply supplies power for a loop is avoided, the second capacitor in the first upper bridge arm circuit is utilized for charging and discharging, the long-term stable power supply is not needed to be additionally provided for the first upper bridge arm circuit, and the working efficiency of the PFC circuit is improved.

In a possible implementation manner of the first aspect, the voltage provided by the first power supply to the second capacitor is greater than the voltage provided by the first auxiliary power supply to the second capacitor. In the embodiment of the application, the voltage provided by the first power supply for the second capacitor is larger than the voltage provided by the first auxiliary power supply for the second capacitor, so that the power supply for the PFC circuit by the first power supply is realized in the starting state of the PFC circuit, the first auxiliary power supply is not required to provide electric energy, and the power supply efficiency of the PFC circuit is improved.

In a possible implementation manner of the first aspect, the PFC circuit further includes a controller, and the controller is further coupled to the first driver for controlling the switching of the first switching tube according to the signal. In the embodiment of the application, the driver is coupled with the controller, so that the driver is controlled by the signal of the controller, and the maneuverability of the scheme is improved.

In a possible implementation manner of the first aspect, when the second capacitor is charged, an input voltage of the first switching tube is smaller than an output voltage of the first power supply. In this embodiment of the present application, when the input voltage of the first switching tube is smaller than the output voltage of the first power supply, the first power supply charges the second capacitor. When the second capacitor is charged, the input voltage of the first switch tube is smaller than the output voltage of the first power supply.

In a possible implementation manner of the first aspect, the first switching tube is at least one of an insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT), a metal-oxide-semiconductor field effect transistor (metal-oxide-semiconductor field-effect transistor, MOSFET) and gallium nitride (GaN).

A second aspect of the present application provides a power supply comprising a PFC circuit as described in any one of the possible embodiments of the first aspect or the first invention.

A third aspect of the present application provides a computing device, characterized in that the computing device comprises the PFC circuit described in the first aspect or any of the possible implementations of the first aspect, or the computing device comprises the power supply described in the second aspect.

A fourth aspect of the present application is a power supply system, wherein the power supply system comprises the PFC circuit described in the first aspect or any of the possible embodiments of the first invention, or wherein the computing device comprises the power supply described in the second aspect.

Drawings

Fig. 1 is a schematic structural diagram of a power supply according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a PFC unit according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a PFC circuit according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of an upper bridge arm circuit according to an embodiment of the present application;

fig. 5 is another schematic structural diagram of an upper bridge arm circuit provided in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a lower bridge arm circuit according to an embodiment of the present disclosure;

fig. 7 is a schematic diagram of totem pole bridgeless PFC according to an embodiment of the present application;

fig. 8 is another schematic diagram of a totem pole bridgeless PFC according to an embodiment of the present disclosure;

fig. 9 is another schematic diagram of a totem pole bridgeless PFC according to an embodiment of the present application;

fig. 10 is another schematic diagram of a totem pole bridgeless PFC according to an embodiment of the present application.

Detailed Description

Embodiments of the present application will now be described with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some, but not all embodiments of the present application. As a person of ordinary skill in the art can know, with the development of technology and the appearance of new scenes, the technical solutions provided in the embodiments of the present application are applicable to similar technical problems.

The terms first, second and the like in the description and in the claims of the present application and in the above-described figures, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. In the present application, "at least one" means one or more, and "a plurality" means two or more. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments described herein may be implemented in other sequences than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In the application scenario of electronic devices, in most cases, the power supply provides ac power for the electronic devices, and in order to ensure that the power supply circuit provides stable dc power for the electronic devices, a power supply is usually disposed in the electronic devices, and converts ac power input into the electronic devices into dc power, and provides dc power for electrical components in the electronic devices.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a power supply according to an embodiment of the present application.

The power supply includes a power correction (power factor correction, PFC) unit, a DC-DC conversion unit, and an electromagnetic compatibility (electro magnetic compatibility, EMC) unit.

And the EMC unit is coupled with the direct current power supply and the PFC unit and is used for eliminating electromagnetic interference in the circuit.

And the PFC unit is coupled with the PFC chip, the capacitor and the ground wire and is used for realizing the mutual conversion of alternating current and direct current.

And the DC-DC change unit is coupled with the capacitor and the ground wire and is used for realizing the voltage conversion of direct current and outputting the voltage converted by the power supply to the outside.

In the related art, referring to fig. 2, fig. 2 is a schematic structural diagram of a PFC unit according to an embodiment of the present application.

In the PFC circuit of the PFC unit shown in fig. 2, the PFC circuit includes an upper arm circuit 21, a lower arm circuit 22, and a capacitor 23.

In the example of the upper bridge arm circuit 21, the upper bridge arm circuit 21 includes a switching tube 211, a floating power supply 212, and a power supply 213, and the switching tube 211 may include at least one of an insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), and gallium nitride (GaN). Such a circuit generally requires a floating power supply 212 when driving the switch of the switching tube 211, and the most common way is to use a bootstrap capacitor to provide the floating power supply for the switch of the switching tube, so in the embodiment of the present application, the floating power supply is taken as an example of the bootstrap capacitor for description.

The bootstrap capacitor 212 needs to be charged by the power supply 213 at the initial stage of circuit operation, when the voltage of the power supply 213 is greater than the input voltage VQDS or VSDS of the switch 211, the power supply 213 charges the bootstrap capacitor 212, in other words, the PFC circuit is shown in fig. 2, if the voltage of the power supply 213 is less than V _QDS Or V _SDS The power supply 213 is unable to charge the bootstrap capacitor 212. If it isThe bootstrap capacitor cannot be charged in the circuit working state, the charge of the bootstrap capacitor is gradually consumed, and the time required for the next charging is longer. In such a circuit, at circuit start-up, it is necessary to wait for the bootstrap capacitor 212 to charge until the voltage across the bootstrap capacitor 212 is above the voltage threshold of the switching PFC circuit of the switching tube 211.

The PFC unit illustrated in fig. 2 is analyzed as follows:

1. when the residual voltage of the capacitor 23 in the PFC unit is greater than the peak value of the input voltage, no charge flows in the circuit, so that the switching tube 211 in the loop is not turned on, the voltage of the power supply 213 is less than the input voltage of the switching tube 211, resulting in a failure of charging the bootstrap capacitor, and further the bootstrap capacitor 212 in the PFC unit cannot be utilized to provide a floating power supply for the switching of the switching tube 211, so that the circuit cannot work normally.

When the pfc unit is connected to the power grid, after the bootstrap capacitor 212 is first charged abnormally, the bootstrap capacitor 212 is only charged again after a half of a working period of the ac power supply, so that the time consumed in the charging process is difficult to control, and the work efficiency of the power supply is greatly affected.

3. When the power supply is directly connected to the direct-current power supply, one half-bridge circuit in the PFC unit cannot be charged, so that the PFC unit cannot normally start to work.

4. In the power standby mode, the power standby state, the PFC discontinuous mode, and the residual voltage of the capacitor 23 is greater than the peak value of the input voltage, the bootstrap capacitor 212 may be not charged or may not be charged.

Based on the above analysis, the operation effect of the bootstrap capacitor 212 is limited by the self-electric quantity of the bootstrap capacitor 212 and the condition of charging the bootstrap capacitor 212 in the loop, so that the bootstrap capacitor 212 cannot be effectively utilized to realize flexible switching of the switching tube 211, and how to realize flexible switching of the switching tube 211 becomes a problem to be solved by a technical personnel.

The application provides a power supply mode which can be adopted for supplying power to the PFC circuit of the upper bridge arm switch tube of the rectifying circuit or the inverting circuit.

The following describes a scheme proposed in the present application by taking a totem bridgeless PFC circuit as an example, referring to fig. 3, fig. 3 is a schematic structural diagram of the PFC circuit provided in the embodiment of the present application.

The totem pole bridgeless PFC circuit shown in fig. 3 includes a first upper arm circuit 30, a second upper arm circuit 31, a first lower arm circuit 32, a second lower arm circuit 33, an inductor 35, a first capacitor 36, and a controller 37. The inductor 35, the first upper bridge arm circuit 30, the first capacitor 36 and the first lower bridge arm circuit 32 are sequentially connected in series, and one end of the inductor 35, which is far away from the first upper bridge arm circuit 30, and one end of the first lower bridge arm circuit 33, which is far away from the first capacitor 36, are respectively connected to two ends of the ac power supply 34. The second upper bridge arm circuit 31 has one end connected between the first upper bridge arm circuit 30 and the first capacitor 36, the other end connected between the first lower bridge arm circuit 32 and the ac power source 34, and the second lower bridge arm circuit 33 has one end connected between the first lower bridge arm circuit 32 and the first capacitor 36, and the other end connected between the inductor 35 and the first upper bridge arm circuit 30.

The first upper arm circuit 30, the second upper arm circuit 31, the first lower arm circuit 32, and the second lower arm circuit 33 constitute one bridge circuit.

First upper leg circuit 30, together with first lower leg circuit 32, inductor 35, and first capacitor 36, operate when the input voltage is at the positive half cycle. Specifically, when the current of the ac power source is in the positive half cycle, the current starts from the ac power source 34, flows through the inductor 35, the first upper arm 30, the first capacitor 36, and the first lower arm 32, and returns to the ac power source 34.

Second upper leg circuit 31, and second lower leg circuit 33, inductor 35, and first capacitor 36 are used to operate when the input voltage is at the negative half cycle. Specifically, when the current of the ac power supply 34 is in the negative half cycle, the current flows from the ac power supply 34, through the second upper arm circuit 31, the first capacitor 36, the second lower arm circuit 33, and the inductor 35, and back to the ac power supply 34.

The ac power supply 34 is used to provide ac power to the PFC circuit.

The controller 37 is coupled to the first upper arm circuit 30, the second upper arm circuit 31, the first lower arm circuit 32, and the second lower arm circuit 33, respectively, and is configured to control the switching of the first upper arm circuit 30, the second upper arm circuit 31, the first lower arm circuit 32, and the second lower arm circuit 33.

The circuits of the first upper bridge arm circuit 30 and the second upper bridge arm circuit 31 are similar, and the first upper bridge arm circuit 30 is taken as an example for illustration, please refer to fig. 3 and fig. 4, and fig. 4 is a schematic diagram of a structure of the upper bridge arm circuit according to an embodiment of the present application.

The first upper bridge arm circuit 30 includes a first PFC circuit 301 and a first switching tube 302;

specifically, the first PFC circuit 301 includes: a first driver 3011 and a first auxiliary power source 3012.

The first driver 3011 may include a first terminal, a second terminal, a signal receiving terminal, and a signal transmitting terminal. A first terminal of the first driver 3011 is connected to a high level of the first auxiliary power supply 3012, and a second terminal of the first driver 3011 is coupled to a low level of the first auxiliary power supply 3012. The first auxiliary power source 3012 is used to supply power to the first driver 3011. The signal receiving end of the first driver 3011 is coupled to the controller 37, and the signal transmitting end of the first driver 3011 is coupled to the first switching tube 302, and is configured to receive a signal transmitted by the controller 37 and control the switching of the first switching tube 302 according to the signal.

The first switching tube 302 may include a control terminal, an input terminal, and an output terminal. The input is coupled to an ac power source 34 via an inductor 35, and the input is also coupled to a second terminal of the first driver 3011 and to a low level of the first auxiliary power source 3012. The output terminal is connected to the first capacitor 36, and the control terminal is connected to the signal transmitting terminal of the first driver 3011. Of course, in other embodiments, the input of the first switching tube 302 may also be directly coupled to the ac power source 34.

Specifically, the first switching tube includes an IGBT, a MOSFET, and GaN.

It should be understood that the description of the first switching tube is merely an example, and in practical application, the description should be set in connection with practical situations, which is not limited herein.

Optionally, in a loop in which the auxiliary power supply supplies power to a driver in the PFC circuit of the upper bridge arm switching tube, a first resistor 3013 is disposed in a circuit in which the first auxiliary power supply 3012 is coupled to the first driver 3011, and the first resistor 3013 is used to protect the first auxiliary power supply 3013. Specifically, one end of the first resistor 3013 is coupled to the high level of the first auxiliary power source 3012, and the other end is connected to the first end of the first driver 3011.

Optionally, in a loop in which the auxiliary power supply supplies power to a driver in the PFC circuit of the upper bridge arm switching tube, a first diode 3014 may be further disposed in a circuit in which the first auxiliary power supply 3012 is coupled to the first driver 3011, where the first diode 3014 is used to prevent current backflow in the loop. Specifically, one end of the first diode 3014 is coupled to the second capacitor 3015 through the first resistor 3013, and the other end of the first diode 3014 is coupled to the high level of the first auxiliary power supply 3012.

Optionally, in a loop in which the auxiliary power supply supplies power to the driver in the PFC circuit of the upper bridge arm switch, a second capacitor 3015 may be further disposed in a circuit in which the first auxiliary power supply 3012 is coupled to the first driver 3011, where the second capacitor 3015 is used to stabilize a voltage difference between the output voltage and the input voltage of the first auxiliary power supply 3012. Specifically, one end of the second capacitor 3015 is connected to the first end of the first driver 3011, and is connected to the high level of the first auxiliary power source 3012 through the first resistor 3013 and the first diode 3014, in other words, one end of the second capacitor 3015 is connected between the first resistor 3013 and the first end of the first driver 3011, and the other end is connected to the second end of the first driver 3011, and the low level of the first auxiliary power source 3012 and the input end of the first switching tube 302.

It should be noted that the first resistor 3013 and/or the first diode 3014 are provided in the circuit coupled between the first auxiliary power supply 301 and the first driver 3011, and in practical application, any electrical component that protects the first auxiliary power supply 3012 when the circuit is shorted may be used to replace the first resistor 3013, and any electrical component that may be used to prevent the current in the circuit from flowing back may be used to replace the first diode 3014, which is not limited herein.

In the embodiment of the application, the electric energy is stably supplied to the driver by utilizing the potential difference of the auxiliary power supply, so that the starting of the driver is prevented from being limited by the output voltage of the bootstrap capacitor, and the switching of the switching tube can be realized more flexibly.

In order to improve the utilization efficiency of electric energy, the embodiment of the application provides that the two loops can simultaneously supply power for the PFC circuit of the upper bridge arm switch tube of the rectifying circuit or the inverting circuit by using the mode of bootstrap capacitor power supply and auxiliary power supply. Referring to fig. 5, fig. 5 is a schematic diagram of another structure of an upper bridge arm circuit according to an embodiment of the present application.

The first upper bridge arm circuit 30 includes a first PFC circuit 301 and a first switching tube 302;

specifically, the first PFC circuit 301 may include: a first driver 3011, a first auxiliary power source 3012, a second capacitor 3015, and a first power source 3016.

The first driver 3011 may include a first terminal, a second terminal, a signal receiving terminal, and a signal transmitting terminal. A first terminal of the first driver 3011 is connected to a high level of the first auxiliary power supply 3012, and a second terminal of the first driver 3011 is coupled to a low level of the first auxiliary power supply 3012. The first auxiliary power source 3012 is used to supply power to the first driver 3011. The signal receiving end of the first driver 3011 is coupled to the controller 37, and the signal transmitting end of the first driver 3011 is coupled to the first switching tube 302, and is configured to receive a signal transmitted by the controller 37 and control the switching of the first switching tube 302 according to the signal.

The first switching tube 302 may include a control terminal, an input terminal, and an output terminal. The input is coupled to an ac power source 34 via an inductor 35, and the input is also coupled to a second terminal of the first driver 3011 and to a low level of the first auxiliary power source 3012. The output terminal is connected to the first capacitor 36, and the control terminal is connected to the signal transmitting terminal of the first driver 3011. Of course, in other embodiments, the input of the first switching tube 302 may also be directly coupled to the ac power source 34.

One end of the second capacitor 3015 is connected between the first end of the first driver 3011 and the high level of the first auxiliary power source 3012, and the other end is connected to the second end of the first driver 3011, the low level of the first auxiliary power source 3012, and the input end of the first switching tube 302. The second capacitor 3015 is used to store power and provide power to the first driver 3011.

The output terminal of the first power source 3016 is connected between the second capacitor 3015 and the first resistor 3013 or the first terminal of the first driver 3011, in other words, the output terminal of the first power source 3016 is connected between the second capacitor 3015 and the first terminal of the first driver 3011 and is also connected to the first resistor 3013.

In the loop of the second capacitor 3015 supplying power to the PFC circuit of the upper bridge arm switch tube, a second diode 3017 and a second resistor 3018 are further connected in series between the first power supply 3016 and the output end of the second capacitor 3015, where the second diode 3017 is used to prevent current from flowing back, protect the first power supply 3016, and simultaneously prevent current from flowing to the first power supply 3016 when the first auxiliary power supply 3012 charges the second capacitor 3015. The second resistor 3018 is used to protect the first power supply 3016 in the event of a short circuit in the loop. Specifically, a second diode 3017 is connected between the first terminal of the first driver 3011 and the second capacitor 3015 via a second resistor 3018, and is coupled to a first power supply 3016.

It should be noted that the arrangement of the second diode 3017 and the second resistor 3018 between the output terminals of the first power supply 3016 and the second capacitor 3015 is merely an example, and any electrical component that can prevent current from flowing backward and that can protect the first power supply 3016 when the circuit is short-circuited may be used for substitution in practical applications, which is not limited herein.

In the circuit where the first auxiliary power supply 3012 supplies power to the PFC circuit of the upper bridge arm switching tube, a first diode 3014 may be further disposed in the circuit where the first auxiliary power supply 3012 is coupled to the first driver 3011, where the first diode 3014 is used to prevent current in the circuit from flowing backward, and meanwhile, to prevent current from flowing to the first auxiliary power supply 3012 when the first power supply 3016 charges the second capacitor 3015. Specifically, one end of the first diode 3014 is connected between the second capacitor 3015 and the first end of the first driver 3011 through the second resistor 3018, and the other end of the first diode 3014 is coupled to the high level of the first auxiliary power supply 3012.

It should be noted that the first diode 3014 is provided in a circuit coupled to the first driver 3011 by the first auxiliary power source 3012, and in practical application, any electrical component that can be used to prevent current backflow in the circuit may be used to replace the first diode 3014, which is not limited herein.

In the embodiment of the application, the mode that the power supply and the auxiliary power supply power to the driver together avoids the condition that long-term stable power supply is needed when only the auxiliary power supply supplies power to the loop. The auxiliary power supply is used for maintaining the voltage of the second capacitor to be larger than the threshold value, so that the PFC circuit can start to work at any time, when the PFC circuit starts to work, the power supply provides electric energy for the second capacitor in the PFC circuit, the auxiliary power supply is not needed to stably provide electric energy for the PFC circuit for a long time, and the working efficiency of the PFC circuit is improved. Compared with the scheme that the existing power supply supplies power to the loop, the scheme utilizes the auxiliary power supply to charge the second capacitor, shortens or even eliminates the charging preparation time of the second capacitor, ensures that the PFC circuit can be started at any time, and improves the flexibility of the scheme.

In some embodiments, the voltage of the first auxiliary power source 3012 is less than the voltage of the first power source 3016, such that the first power source 3016 charges the second capacitor 3015 when the input voltage of the first switching tube 302 is less than the voltage of the first power source 3016, and the first auxiliary power source 3012 charges the second capacitor 3015 when the input voltage of the first switching tube 302 is greater than or equal to the voltage of the first power source 3016. Therefore, when the first power supply 3016 can charge the second capacitor 3015, the first power supply 3016 is used for charging the second capacitor, when the first power supply 3016 cannot charge the second capacitor 3015, the first auxiliary power supply 3012 is used for charging, the problem that the service life of the first auxiliary power supply 3012 is seriously lost due to the fact that the first auxiliary power supply 3012 is always used for charging is avoided, and the service life of the first auxiliary power supply 3012 is prolonged.

Of course, in other embodiments, the voltage of the first auxiliary power source 3012 may also be equal to the voltage of the first power source 3016.

The first lower bridge arm circuit 32 is similar to the second lower bridge arm circuit 33, and the first lower bridge arm circuit 32 is taken as an example for description, refer to fig. 6, and fig. 6 is a schematic diagram of a lower bridge arm circuit according to an embodiment of the present application.

The first lower bridge arm circuit 32 includes a second PFC circuit 321 and a second switching tube 322;

specifically, the second PFC circuit 321 includes: a third capacitor 3211, a second driver 3212, and a second power source 3213.

It is to be understood that the structure of the second driver 3212 is the same as that of the first driver 3011, and the connection relationship between the second driver 3212 and the second power source 3213, the second switching tube 322, and the third capacitor 3211 is the same as that between the first driver 3011 and the first capacitor 36, the first switching tube 302, and the second capacitor 3015, and reference is made to the description of the first driver 3011.

A third capacitor 3211 is coupled to the second driver 3212, the input of the second switching tube 322 and the second power source 3213 for storing electrical energy and providing electrical energy to the second driver 3212.

And a second driver 3212 coupled to the control terminal of the second switching tube 322, the output terminal of the second power source 3213, and the controller 37, for receiving a signal transmitted from the controller 37 and controlling the switching of the second switching tube 322 according to the signal.

The second power source 3213 and the output end of the third capacitor 3211 are further connected in series with a third diode 3214 and a third resistor 3215, where the third diode 3214 is used for preventing current from flowing back and protecting the second power source 3213. The third resistor 3215 is used to protect the second power source 3213 when the loop is shorted.

It should be noted that, the arrangement of the third diode 3214 and the third resistor 3215 between the second power source 3213 and the output terminal of the third capacitor 3211 is merely an example, and any electrical component that can prevent current from flowing backward and that can protect the second power source 3213 when the circuit is short-circuited may be used for replacement in practical applications, which is not limited herein.

Since the input terminal of the first lower bridge arm circuit 32 is coupled to the floating ground terminal of the first capacitor 36, the input terminal of the first lower bridge arm circuit 32 is infinitely close to 0v, and the second PFC circuit 321 in the first lower bridge arm circuit 32 can charge the third capacitor 3211 at any time. The second PFC circuit 321 can thus also control the second switching tube 322 without providing an auxiliary power supply.

Therefore, the scheme of supplying power to the PFC circuit of the upper bridge arm switch tube by the auxiliary power supply in the lower bridge arm circuit is not necessary in practical application, and is not described here.

The following description is made with reference to fig. 3, fig. 4, and fig. 6 in the specific application case of totem pole bridgeless PFC provided in the embodiments of the present application, that is, a scenario in which an upper bridge arm circuit uses an auxiliary power supply to supply power to a driver in an upper bridge arm switching tube PFC circuit, and a lower bridge arm uses a bootstrap capacitor to supply power to a driver in a lower bridge arm switching tube PFC circuit. In this scenario, since the waveform of the output voltage of the ac power supply may be positive half cycle or negative half cycle, the directions of the currents in the circuit are described corresponding to the different directions of the currents in the totem pole bridgeless PFC.

1. When the output voltage of the ac power source is at the positive half cycle.

Referring to fig. 7, fig. 7 is a schematic diagram of a totem pole bridgeless PFC according to an embodiment of the present application.

In the circuit shown in fig. 7, the first auxiliary power source 3012 of the first upper bridge arm 30 supplies power to the first driver 3011, so that the first driver 3011 can implement switching control on the first switching tube 302 at any time after receiving the switching signal sent by the controller 37. It is realized that when the waveform of the output voltage of the ac power supply 34 is positive half cycle, a current flows from the inductor 35 through the first upper arm circuit 30, the first capacitor 36 and the first lower arm circuit 32 to form a loop.

2. When the output voltage of the ac power source is at the negative half cycle.

Referring to fig. 8, fig. 8 is another schematic diagram of a totem pole bridgeless PFC according to an embodiment of the present disclosure.

In the circuit shown in fig. 8, the first auxiliary power source 3012 of the second upper bridge arm 31 supplies power to the first driver 3011, so that the first driver 3011 can implement switching control on the first switching tube 302 at any time after receiving the switching signal sent by the controller 37. When the waveform of the output voltage of the ac power supply 34 is negative half cycle, it is realized that a current flows from the inductor 35 through the second upper arm circuit 31, the first capacitor 36 and the second lower arm circuit 33 to form a loop.

The following description is made with reference to fig. 3, fig. 5, and fig. 6 in the specific application case of totem pole bridgeless PFC provided in the embodiments of the present application, that is, a scenario in which an auxiliary power supply and a power supply dual loop are adopted in an upper bridge arm circuit to supply power to a driver in an upper bridge arm switching tube PFC circuit, and a lower bridge arm adopts a power supply to supply power to a driver in a lower bridge arm switching tube PFC circuit.

1. When the output voltage of the ac power source is at the positive half cycle.

Referring to fig. 9, fig. 9 is another schematic diagram of a totem pole bridgeless PFC according to an embodiment of the present disclosure.

In the circuit shown in fig. 9, the first driver 3011 in the PFC circuit of the upper bridge arm switching tube is powered by using the first auxiliary power source 3012 and the first power source 3016 in a double loop manner, so that the first driver 3011 can realize switching control on the first switching tube 302 at any time after receiving the switching signal sent by the controller 37. It is realized that when the waveform of the output voltage of the ac power supply 34 is positive half cycle, a current flows from the inductor 35 through the first upper arm circuit 30, the first capacitor 36 and the first lower arm circuit 32 to form a loop.

The flow of the auxiliary power supply and the power supply dual-loop for supplying power to the driver in the PFC circuit of the upper bridge arm switch tube is described by means of figure 5, and comprises:

when the input voltage of the first switching transistor 302 is smaller than the output voltage of the first power source 3016, the first power source 3016 charges the second capacitor 3015.

When the input voltage of the first switching transistor 302 is greater than or equal to the output voltage of the first power source 3016, the first auxiliary power source 3012 charges the second capacitor 3015 and supplies power to the first driver 3011.

To achieve the above-described timing of supplying power to the driver by the dual circuits, it is necessary to ensure that the difference between the output voltage of the first power source 3016 and the divided voltage of the first resistor 3018 is still greater than the output voltage of the first auxiliary power source 3012.

2. When the output voltage of the ac power source is at the negative half cycle.

Referring to fig. 10, fig. 10 is another schematic diagram of a totem pole bridgeless PFC according to an embodiment of the present disclosure.

In the circuit shown in fig. 10, the first driver 3011 in the PFC circuit of the upper bridge arm switching tube is powered by using the first auxiliary power source 3012 and the first power source 3016 in a double loop manner, so that the switching control of the switching tube 302 can be implemented at any time after the first driver 3011 receives the switching signal sent by the controller 37. When the waveform of the output voltage of the ac power supply 34 is negative half cycle, it is realized that a current flows from the inductor 35 through the second upper arm circuit 31, the first capacitor 36 and the second lower arm circuit 33 to form a loop.

At this time, the flow of supplying power to the driver in the PFC circuit of the upper bridge arm switch tube by the auxiliary power supply and the bootstrap dual circuit is similar to that in fig. 9, and will not be repeated here.

The PFC circuit provided in the present application is described above, and the computing device and the power supply system provided in the embodiments of the present application are described below respectively.

The computing device comprises a power supply, wherein the power supply comprises a PFC circuit, and the PFC circuit is connected with an alternating current power supply, is used for converting alternating current energy provided by the alternating current power supply into direct current energy and provides electric energy for electric equipment. The PFC circuit is similar to the PFC circuits described in fig. 3 to 9, and will not be described here.

In another embodiment, a PFC circuit is disposed in the computing device, and the PFC circuit is connected to an ac power source, and is configured to convert ac power provided by the ac power source into dc power, and to provide power to a power circuit in the computing device. The PFC circuit is similar to the PFC circuits described in fig. 3 to 9, and will not be described here.

The power supply system comprises a power supply, wherein the power supply comprises a PFC circuit, and the PFC circuit is connected with an alternating current power supply and is used for converting alternating current energy provided by the alternating current power supply into direct current energy and providing electric energy for electric equipment. The PFC circuit is similar to the PFC circuits described in fig. 3 to 9, and will not be described here.

In another embodiment, the power supply system includes a PFC circuit, where the PFC circuit is connected to an ac power source, and is configured to convert ac power provided by the ac power source into dc power and provide power to the electrical device. The PFC circuit is similar to the PFC circuits described in fig. 3 to 9, and will not be described here.

Claims (10)

1. A power factor correction, PFC, circuit comprising: the first capacitor is connected between the first upper bridge arm circuit and the first lower bridge arm circuit, the first upper bridge arm and the first lower bridge arm are connected with an alternating current power supply, and the first upper bridge arm circuit and the first lower bridge arm circuit work cooperatively to change alternating current output by the alternating current power supply into direct current;

the first upper bridge arm circuit comprises a first driver, a first auxiliary power supply, a first switch tube and a second capacitor, wherein the first switch tube comprises a control end, an input end and an output end, the input end is coupled with the alternating current power supply, the output end is connected with the first capacitor, the control end is connected with the first driver, the first driver is used for driving a switch of the first switch tube, one end of the second capacitor is connected with the first driver, the other end of the second capacitor is connected with the input end, the low level of the first auxiliary power supply is connected to the input end, and the high level of the first auxiliary power supply is connected to the second capacitor and is used for providing electric energy for the first driver.

2. The PFC circuit of claim 1 wherein the first upper leg circuit further comprises: a first diode;

and one end of the first diode is connected with the second capacitor and the first driver, and the other end of the first diode is connected with the high level of the first auxiliary power supply and is used for preventing current from flowing back to the output end of the first auxiliary power supply.

3. The PFC circuit of claim 1 or 2, wherein the first upper leg circuit further comprises: a first power supply and a second diode;

one end of the second diode is connected with the first driver and the second capacitor, and the other end of the second diode is coupled with the first power supply and is used for preventing current from flowing back to the output end of the first power supply;

the first power supply is used for providing electric energy for the second capacitor when the input voltage of the first switch tube is smaller than the output voltage of the first power supply.

4. The PFC circuit of claim 3 wherein the first power supply provides a voltage to the second capacitor that is greater than a voltage provided by the first auxiliary power supply to the second capacitor.

5. The PFC circuit according to any of claims 1 to 4, further comprising a controller, the first driver being coupled to the controller for controlling switching of the first switching tube in dependence on a signal.

6. The PFC circuit according to any of claims 1 to 5, wherein an input voltage of the first switching tube is less than an output voltage of the first power supply when the first power supply charges the second capacitor.

7. The PFC circuit according to any of claims 1 to 5, wherein the first switching tube is at least one of an IGBT, a MOSFET, or GaN.

8. A power supply comprising the PFC circuit of any of claims 1 to 7.

9. A computing device comprising the PFC circuit of any of claims 1-7; alternatively, the computing device comprises the power supply of claim 8.

10. A power supply system, characterized in that it comprises the PFC circuit of any one of claims 1 to 7; alternatively, the computing device comprises the power supply of claim 8.

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