Totem pole power factor correction circuit, power supply system, compressor and air conditioning equipment

Abstract

This disclosure relates to the technical field of AC power input to DC power output conversion, specifically providing a totem-pole power factor correction circuit, a power supply system, a compressor, and an air conditioning device. The totem-pole power factor correction circuit includes a rectifier module, an inductor module, a capacitor module, a switch module, and a control module. The capacitor module is connected in parallel with the output of the rectifier module. The capacitor module includes a series branch and a parallel branch. The series branch includes a first capacitor and a second capacitor connected in series, and the parallel branch includes at least one third capacitor connected in parallel across the two ends of the series branch. This disclosure, by using a parallel third capacitor, effectively suppresses bus voltage ripple, fundamentally enhancing the stability and reliability of the circuit under dynamic load changes. It solves the industry pain point of DC bus ripple in totem-pole PFC circuits, achieving a balance of "high efficiency, low ripple, and low cost."

Description

Technical Field

[0001] This disclosure relates to the field of electronic circuit technology, and in particular to a totem pole power factor correction circuit, a power supply system, a compressor, and an air conditioning device. Background Technology

[0002] In the field of power electronics, power factor correction (PFC) circuits are key components for improving grid efficiency and reducing harmonic pollution, and are widely used in medium-to-high power applications such as switching power supplies, industrial motor drives, electric vehicle charging systems, and data center power supplies. With increasingly stringent global standards for energy efficiency and electromagnetic compatibility (EMC) (such as IEC 61000-3-2), high-efficiency, low-harmonic PFC technology has become a core industry requirement. The totem-pole (T-type) topology has been widely used in PFC circuits in recent years due to its high efficiency, low switching losses, and simplified control, especially suitable for systems with wide input voltage ranges and large dynamic load changes.

[0003] However, in the totem-pole PFC circuit of related technologies, the ripple of the bus voltage increases significantly when the load changes dynamically. Excessive voltage ripple can cause a series of problems: First, it may cause stability issues in subsequent DC-DC or inverter circuits, affecting the overall performance; second, the increased ripple current will exacerbate the heating of the capacitors themselves, affecting their lifespan and system reliability; finally, voltage fluctuations may be more severe during light loads or specific operating mode switching, limiting the performance optimization of the circuit across the entire load range. Summary of the Invention

[0004] In view of this, in order to solve the technical problem that the bus voltage ripple of the totem pole power factor correction circuit increases significantly when the load changes dynamically, this disclosure provides a totem pole power factor correction circuit, a power supply system, a compressor, and an air conditioning device.

[0005] According to a first aspect of the present disclosure, a totem pole power factor correction circuit is provided, the totem pole power factor correction circuit comprising: The rectifier module has an input terminal for connecting to an AC power source and an output terminal for connecting to a load. An inductor module is connected in series between the AC power supply and the input terminal of the rectifier module; A capacitor module is connected in parallel with the output terminal of the rectifier module. The capacitor module includes a series branch and a parallel branch. The series branch includes a first capacitor and a second capacitor connected in series. The parallel branch includes at least one third capacitor. The parallel branch is connected in parallel across the two ends of the series branch. The switching module has one end connected to one input terminal of the rectifier module and the other end connected to the connection point of the first capacitor and the second capacitor. The control module is configured to control the rectifier module and the switching module to operate in high-frequency switching mode or synchronous rectification mode according to the operating parameters of the load.

[0006] In one alternative implementation, The equivalent capacitance of the parallel branch is greater than or equal to the equivalent capacitance of the first capacitor and the second capacitor connected in series.

[0007] In one alternative implementation, The parallel branch includes an electrolytic capacitor with an equivalent series resistance of less than 50mΩ.

[0008] In one alternative implementation, The first capacitor and the second capacitor have the same capacitance value; and / or, The first capacitor and the second capacitor have the same voltage rating.

[0009] In one alternative implementation, When the totem pole power factor correction circuit is applied to a power supply system with a rated output power of 1kW and a rated input of 230V AC: The capacitance of the first capacitor is greater than or equal to 100μF, and its voltage rating is greater than or equal to 250V; and / or, The capacitance of the second capacitor is greater than or equal to 100μF, and its withstand voltage is greater than or equal to 250V.

[0010] In one alternative implementation, The totem pole power factor correction circuit is configured such that, when the load is in the range of 20% to 100%, the power factor of the totem pole power factor correction circuit is greater than 0.99.

[0011] According to a second aspect of the present disclosure, a power system for a data center is provided, the power system including a totem pole power factor correction circuit as described in any of the first aspects.

[0012] In one alternative implementation, The rated output power of the power supply system is 1kW, and the rated input of the power supply system is 230V AC power.

[0013] According to a third aspect of the present disclosure, a compressor is provided, the compressor comprising: The totem pole power factor correction circuit as described in any of the first aspects; An inverter, the input of which is connected to the output of the rectifier module in the totem pole power factor correction circuit; The motor is connected to the output terminal of the inverter.

[0014] According to a fourth aspect of the present disclosure, an air conditioning device is provided, the air conditioning device including a compressor as described in the third aspect.

[0015] The technical solutions provided by the embodiments of this disclosure can include the following beneficial effects: In this disclosure, in high-voltage input applications, to distribute voltage stress, a series connection of two capacitors (a first capacitor and a second capacitor) is used in the totem-pole PFC circuit. However, this series structure introduces a significant inherent drawback: the equivalent capacitance is reduced, that is, the total equivalent capacitance of the DC bus is reduced after series connection. This directly leads to a decrease in the filtering capability of the DC bus, a significant increase in voltage ripple, which may in turn cause stability problems in subsequent circuits, increase losses, and restrict the improvement of overall efficiency. Based on this, this disclosure also connects a third capacitor in parallel. That is, the third capacitor is directly connected in parallel across the two ends of the branch where the series capacitor is located. This design instantly increases the total equivalent capacitance of the DC bus to ground to C_eq + Cbig, where C_eq is the equivalent capacitance after the first and second capacitors are connected in series, and Cbig is the capacitance value of the parallel third capacitor. This disclosure effectively suppresses bus voltage ripple by adding a third capacitor in parallel, providing an extremely smooth and stable DC voltage source for subsequent inverter or DC-DC converter stages, fundamentally enhancing the circuit's stability and reliability under dynamic load changes. Crucially, this disclosure achieves high performance with an optimal cost structure. It cleverly employs a combination strategy of "the first and second capacitors connected in series to meet the withstand voltage requirements, and the third capacitor in parallel to enhance filtering," achieving performance exceeding traditional solutions with minimal incremental cost, demonstrating extremely high engineering cost-effectiveness. In other words, this disclosure solves the industry pain point of DC bus ripple in totem-pole PFC circuits with minimal structural changes by adding a parallel capacitor to the existing series capacitors, achieving a balance of "high efficiency, low ripple, and low cost." This is a key optimization for totem-pole PFC topologies in industrial applications.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0019] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0020] Figure 1 This is a totem pole power factor correction circuit illustrated according to an exemplary embodiment.

[0021] Figure 2 This is a totem pole power factor correction circuit illustrated according to another exemplary embodiment.

[0022] in: 10. Capacitor module; C1, First capacitor; C2, Second capacitor; C3, Third capacitor; 20. Rectifier module; D1, First unidirectional conduction unit, Second unidirectional conduction unit, Third unidirectional conduction unit, Fourth unidirectional conduction unit; Q1, First switching unit, Second switching unit, Third switching unit, and Fourth switching unit; 30. Load; 31. Inverter; 32. Motor; SW, Switching module; L, Inductor module. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] The following disclosure provides numerous different embodiments or examples for implementing various aspects of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0025] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0026] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0027] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0028] To address the technical problem of significantly increased bus voltage ripple in existing totem pole power factor correction circuits under dynamic load changes, this disclosure provides a totem pole power factor correction circuit, a power supply system, a compressor, and an air conditioning device.

[0029] In this disclosure, for high-voltage input applications, to distribute voltage stress, the totem-pole PFC circuit employs a series connection of two capacitors (a first capacitor and a second capacitor). However, this series structure introduces a significant inherent drawback: reduced equivalent capacitance. That is, the total equivalent capacitance of the DC bus decreases after series connection, directly leading to a decline in the DC bus's filtering capability, a significant increase in voltage ripple, and potentially causing stability issues in subsequent circuits, increased losses, and limiting overall efficiency improvement. Based on this, this disclosure also includes a third capacitor connected in parallel. Specifically, the third capacitor is directly connected in parallel across the branch containing the series capacitors. This design instantly increases the total equivalent capacitance of the DC bus to ground to C_eq + Cbig, where C_eq is the equivalent capacitance of the first and second capacitors connected in series, and Cbig is the capacitance value of the parallel-connected third capacitor. By using a parallel third capacitor, this disclosure effectively suppresses bus voltage ripple, providing an extremely smooth and stable DC voltage source for subsequent inverter or DC-DC converter stages, fundamentally enhancing the circuit's stability and reliability under dynamic load changes. Most importantly, this disclosure achieves high performance with an extremely optimized cost structure. It cleverly employs a combination strategy of "connecting the first and second capacitors in series to meet voltage withstand requirements, and connecting the third capacitor in parallel to enhance filtering," achieving performance superior to traditional solutions with minimal incremental cost, demonstrating extremely high engineering cost-effectiveness. In other words, this disclosure solves the industry pain point of DC bus ripple in totem-pole PFC circuits with minimal structural change by adding a parallel capacitor to the existing series capacitors, achieving a balance of "high efficiency, low ripple, and low cost." This is a key optimization for totem-pole PFC topologies in industrial applications.

[0030] In one exemplary embodiment, reference Figure 1 and Figure 2 As shown, a totem pole power factor correction (PFC) circuit is provided. This totem pole PFC circuit may include a rectifier module 20, an inductor module L, a capacitor module 10, a switch module SW, and a control module (not shown in the figure).

[0031] The rectifier module 20 has an input terminal for connecting to an AC power supply and an output terminal for connecting to a load 30. The rectifier module 20 includes multiple unidirectional conducting units and multiple switching units. These unidirectional conducting units are connected in a bridge configuration, with each unidirectional conducting unit connected in parallel with a switching unit. In embodiments of the invention, diodes can be used as unidirectional conducting units, or other devices with unidirectional conducting capability can be used; transistors, field-effect transistors, or insulated-gate bipolar transistors (IGBTs) with controlled switching capability can be used as switching units.

[0032] For example, the rectifier module 20 includes a first unidirectional conducting unit D1, a second unidirectional conducting unit D2, a third unidirectional conducting unit D3, a fourth unidirectional conducting unit D4, a first switching unit Q1, a second switching unit Q2, a third switching unit Q3, and a fourth switching unit Q4. The unidirectional conducting units are connected in a bridge configuration, meaning that the positive terminal of the first unidirectional conducting unit D1 is connected to the negative terminal of the second unidirectional conducting unit D2, the positive terminal of the third unidirectional conducting unit D3 is connected to the negative terminal of the fourth unidirectional conducting unit D4, the negative terminal of the first unidirectional conducting unit D1 is connected to the negative terminal of the third unidirectional conducting unit D3, and the positive terminal of the second unidirectional conducting unit D2 is connected to the positive terminal of the fourth unidirectional conducting unit D4. Each unidirectional conduction unit is connected in parallel with a switching unit, meaning that the first unidirectional conduction unit D1 is connected in parallel with the first switching unit Q1, the second unidirectional conduction unit D2 is connected in parallel with the second switching unit Q2, the third unidirectional conduction unit D3 is connected in parallel with the third switching unit Q3, and the fourth unidirectional conduction unit D4 is connected in parallel with the fourth switching unit Q4.

[0033] In this embodiment, in the rectifier module 20 composed of devices such as the first unidirectional conduction unit D1 and the first switching unit Q1, the negative terminal of the first unidirectional conduction unit D1 and the positive terminal of the second unidirectional conduction unit D2 are the output terminals of the rectifier module 20, and the positive terminals of the first unidirectional conduction unit D1 and the third unidirectional conduction unit D3 are the input terminals of the rectifier module 20.

[0034] In this embodiment, the inductor module L is connected in series between the AC power supply AC and the input terminal of the rectifier module 20. That is, the input terminal of the rectifier module 20 is connected to the AC power supply AC through the inductor module L, and the output terminal of the rectifier module 20 is connected to the load 30. Additionally, in this embodiment, the capacitor module 10 is connected in parallel with the output terminal of the rectifier module 20.

[0035] The capacitor module 10 includes a series branch, which comprises a first capacitor C1 and a second capacitor C2 connected in series. A switch module SW is connected between one input terminal of the rectifier module 20 and the capacitor module 10. One end of the switch module SW is connected to one input terminal of the rectifier module 20, and the other end is connected to the connection point of the first capacitor C1 and the second capacitor C2. Specifically, one end of the switch module SW is connected to the positive terminal of the third unidirectional conduction unit D3 in the rectifier module 20, and the other end of the switch module SW is connected to the connection point of the first capacitor C1 and the second capacitor C2. The switch module SW has two states: on and off. When the switch module SW is on, the positive terminal of the third unidirectional conduction unit D3 is connected to the connection point of the first capacitor C1 and the second capacitor C2; when the switch module SW is off, the positive terminal of the third unidirectional conduction unit D3 is disconnected from the connection point of the first capacitor C1 and the second capacitor C2.

[0036] The control module is configured to control the rectifier module 20 and the switch module SW to operate in either a high-frequency switching mode or a synchronous rectification mode, based on the operating parameters of the load 30. Additionally, in this embodiment, the capacitor module 10 includes a parallel branch, which comprises at least one third capacitor C3, and is connected in parallel across the series branch. This embodiment effectively increases the total equivalent capacitance of the capacitor module 10 by connecting a parallel branch with at least one third capacitor C3 to the series capacitor, thereby improving the overall circuit performance.

[0037] In this embodiment, two capacitors (first capacitor C1 and second capacitor C2) are connected in series to distribute the high voltage. However, this results in the equivalent capacitance C_eq1 of the two capacitors being halved (C_eq1 = C1). The capacitance C2 / (C1+C2) leads to insufficient DC bus filtering capability and large voltage ripple. Therefore, this embodiment adds a parallel branch with at least one third capacitor C3 across the series branch. In this case, the total equivalent capacitance of the DC bus becomes C_eq1 + C_eq2, where C_eq1 is the equivalent capacitance of the first capacitor C1 and the second capacitor C2 in series, and C_eq2 is the equivalent capacitance of the parallel branch. That is, this embodiment increases the total equivalent capacitance of the DC bus in the entire totem-pole PFC circuit (for example, by reasonably setting the equivalent capacitance of the parallel branch (e.g., making it greater than or equal to the equivalent capacitance of the first capacitor C1 and the second capacitor C2 in series), which can increase the total equivalent filtering capacitance by several times), directly resulting in a significant reduction in the bus voltage ripple amplitude. The smoother DC voltage provides a more stable operating platform for subsequent circuits (such as inverter 31 and DC-DC converter), significantly enhancing the stability and reliability of the entire power system under dynamic load changes, and avoiding performance degradation or false triggering of protection due to voltage fluctuations.

[0038] It should be noted that, without adopting this embodiment, there are two traditional approaches to achieve the same ripple suppression effect: one is to use a single capacitor with a higher voltage rating and larger capacitance, but high-voltage capacitors are expensive (the document indicates that the cost may increase by more than 35%); the other is to proportionally increase the capacitance of the two series capacitors, but this leads to a simultaneous increase in cost and size, and low efficiency improvement. This embodiment adds a parallel branch with at least one third capacitor C3 to the series capacitors, and the third capacitor C3 in this parallel branch can be a relatively inexpensive standard electrolytic capacitor, cleverly solving this problem. The first capacitor C1 and the second capacitor C2 can still be medium-sized capacitors that meet the basic voltage requirements, while the capacitors in the parallel branch undertake the main tasks of ripple current absorption and energy storage enhancement. This combination of "first capacitor C1 and second capacitor C2 in series to meet the voltage requirements, and third capacitor C3 in parallel to enhance filtering" achieves performance comparable to or even better than a solution using a single high-cost, high-voltage, large-capacity capacitor without significantly increasing the overall cost and size, demonstrating extremely high cost-effectiveness and engineering application value.

[0039] That is, this embodiment, through the introduction of a parallel branch with at least one third capacitor C3, achieves multiple technical effects such as ripple suppression, enhanced stability, cost savings, reduced losses, extended lifespan, and guaranteed high efficiency at full load through a simple yet ingenious structural innovation. It fundamentally solves the inherent contradictions in the DC bus design of existing totem-pole PFC circuits and is a key optimization of totem-pole PFC topology in industrial applications, providing key technical support for the development of high-efficiency, high-reliability power supply products and compressor products.

[0040] In one exemplary embodiment, reference Figure 1 and Figure 2 As shown, a totem pole power factor correction (PFC) circuit is provided. In this totem pole PFC circuit, the equivalent capacitance of the parallel branch is greater than or equal to the equivalent capacitance of the first capacitor C1 and the second capacitor C2 connected in series.

[0041] It should be noted that in high-voltage input applications, it is common practice to connect the first capacitor C1 and the second capacitor C2 in series to distribute voltage stress. However, this significantly reduces the equivalent capacitance C_eq1 after series connection. The calculation formula is C_eq1 = (C1...) C2) / (C1 + C2). When the capacitance values ​​of the first capacitor C1 and the second capacitor C2 are the same, C_eq1 is only half the value of a single capacitor. This "halved" equivalent capacitance is the direct cause of insufficient DC bus filtering capability and increased voltage ripple.

[0042] The core of this embodiment is to connect at least one third capacitor C3 in parallel on the series branch, and the equivalent capacitance of the parallel branch is denoted as C_eq2. Its purpose is not only to simply "compensate" for the capacity loss caused by series connection, but to significantly improve the total filtering ability of the DC bus, so as to achieve the effects of suppressing ripples and improving stability.

[0043] Among them, the calculation formula for the total equivalent capacitance is: C_total = C_eq1 + C_eq2. If C_eq2 < C_eq1: For example, C_eq1 = 50 μF and C_eq2 = 10 μF, then C_total = 60 μF. The total equivalent capacitance is only 20% higher than the original series scheme, and the improvement effect is minimal, and the fundamental problem of excessive ripples cannot be solved. If C_eq2 ≥ C_eq1: For example, C_eq1 = 50 μF and C_eq2 = 100 μF, then C_total = 150 μF. The total capacitance reaches three times that of the original series scheme. Such an improvement in magnitude can produce significant technical effects such as "substantially reducing the amplitude of the bus voltage ripple" and "providing a more stable working platform for the subsequent circuit".

[0044] In addition, in the related art solutions to avoid the increase of the bus voltage ripple, either expensive high-voltage single large capacitors are selected, or the capacitance values of the first capacitor C1 and the second capacitor C2 are increased同比. However, both of these two solutions have high costs or large volume penalties. The ingenuity of the solution of this embodiment is that the first capacitor C1 and the second capacitor C2 only need to meet the basic withstand voltage requirements (such as 250V), and maintain a small capacitance to control costs; and by connecting at least one parallel branch with a "sufficiently large capacitance (equivalent capacitance C_eq2 ≥ C_eq1) but the same withstand voltage requirements as the first capacitor C1 and the second capacitor C2" in parallel, to undertake the main filtering enhancement task. By setting C_eq2 ≥ C_eq1 in this embodiment, it can well ensure that the equivalent capacitance of the parallel branch can produce a visible and decisive performance improvement in engineering, which can make the total filtering capacitance increase several times, thus fundamentally solving the ripple problem.

[0045] In some embodiments, Refer to Figure 1 As shown, the capacitor module 10 in this embodiment consists of a series branch and a parallel branch. The parallel branch includes a third capacitor C3, and the series branch includes a first capacitor C1 and a second capacitor C2.

[0046] To adapt to the high-voltage DC bus after rectifying the 230V AC input and control costs at the same time, this embodiment selects the first capacitor C1 and the second capacitor C2 as standard electrolytic capacitors with the same parameters: the capacitance is 100 μF each, and the rated withstand voltage is 250V each. According to the capacitor series formula, the equivalent capacitance C_eq1 after the first capacitor C1 and the second capacitor C2 are connected in series is: C_eq1 = (100μF 100μF) / (100μF + 100μF) = 50μF.

[0047] The third capacitor C3 is connected directly in parallel across the series branch. To achieve significant filtering enhancement, this embodiment sets the capacitance (i.e., capacitance value) of the third capacitor C3 to 50μF and its rated withstand voltage to 250V. Therefore, the equivalent capacitance C_eq2 of the parallel branch is 50μF.

[0048] Based on this, the total equivalent capacitance C_total on the DC bus side of this embodiment is: C_total = C_eq1 + C_eq2 = 50μF + 50μF = 100μF.

[0049] Clearly, the equivalent capacitance of the parallel branch (50μF) is equal to that of the series branch (50μF), satisfying the condition C_eq2 ≥ C_eq1. This increases the total equivalent capacitance to twice that of the original series scheme, thus strongly suppressing bus voltage ripple.

[0050] It should be noted that the third capacitor C3 in this embodiment can also be greater than 50μF, thereby improving the filtering effect and better suppressing bus voltage ripple. Furthermore, the specifications of the first capacitor C1 and the second capacitor C2 can be the same or different; this is not limited. That is, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 can be the same or different. The withstand voltage values ​​of the first capacitor C1 and the second capacitor C2 can also be the same or different; this is not limited. Additionally, the capacitance and withstand voltage values ​​of the first capacitor C1 and the second capacitor C2 in the above embodiment are minimum requirements; that is, larger capacitance and withstand voltage values ​​than those in the above embodiment can also be used; this is not limited.

[0051] In other implementations, refer to Figure 2 As shown, the series branch in this embodiment is the same as in the embodiment described above, and will not be repeated here. The parallel branch in this embodiment may include two third capacitors C3. This design can distribute the ripple current of a single capacitor, further reducing thermal stress and improving reliability. The capacitance of both third capacitors C3 is set to 47μF, and their rated withstand voltage is 250V. When the two third capacitors C3 are connected in parallel, the total equivalent capacitance C_eq2 of the parallel branch is the sum of their capacitances: C_eq2 = 47μF + 47μF = 94μF.

[0052] At this time, the total equivalent capacitance C_total on the DC bus side is: C_total = C_eq1 + C_eq2 = 50μF + 94μF = 144μF.

[0053] In this design, the equivalent capacitance of the parallel branch (94μF) is also greater than that of the series branch (50μF), satisfying the requirement that C_eq2 ≥ C_eq1. The total equivalent capacitance is about 2.9 times that of the original series scheme, and it can still achieve excellent ripple suppression effect.

[0054] It should be noted that in this embodiment, the specifications of the two third capacitors C3 in the parallel branch can be the same or different, and this is not limited. Similarly, the specifications of the first capacitor C1 and the second capacitor C2 can be the same or different, and this is not limited. That is, the capacitance values ​​of the first capacitor C1 and the second capacitor C2 can be the same or different. The voltage ratings of the first capacitor C1 and the second capacitor C2 can also be the same or different, and this is not limited. Furthermore, the capacitance and voltage ratings of the first capacitor C1 and the second capacitor C2 in the above embodiment are minimum requirements; that is, larger capacitance and voltage ratings than those in the above embodiment can also be used, and this is not limited.

[0055] The two implementation methods described above demonstrate two feasible paths to achieve the core features of this embodiment through specific parameters. Whether using a single large-capacity capacitor or two slightly smaller capacitors connected in parallel, the common point is that the parallel branch provides an equivalent capacitance no less than that of the series branch, thereby increasing the total filter capacitance of the DC bus several times over. This directly results in a significant reduction in voltage ripple and enhanced system stability.

[0056] In one exemplary embodiment, reference Figure 1 and Figure 2 As shown, a totem-pole power factor correction (PFC) circuit is provided. In this totem-pole PFC circuit, the parallel branch includes an electrolytic capacitor with an equivalent series resistance (ESR) of less than 50mΩ. That is, the third capacitor C3 in the parallel branch can be an electrolytic capacitor with an equivalent series resistance of less than 50mΩ.

[0057] It's important to note that ESR is not a separate, additional resistor. Rather, it characterizes the equivalent resistance of a real capacitor when it operates in a circuit, reflecting the combined effects of all losses inherent in its internal structure (e.g., electrodes, leads, dielectric material). In a circuit model, a real capacitor can be viewed as a series connection of an "ideal capacitor C" and a "small resistance ESR".

[0058] In the field of power electronics, when a large capacitance (e.g., tens to hundreds of microfarads) is required within a limited size and cost budget, electrolytic capacitors typically offer a smaller size and lower unit cost compared to other types of capacitors (e.g., film capacitors, ceramic capacitors) at the same capacitance and voltage level. In this solution, the third capacitor C3 needs to provide a significant additional capacitance (e.g., 100μF) to increase the total equivalent capacitance. Using an electrolytic capacitor ensures that this solution can be implemented without significantly increasing the overall size and material cost of the power module, thus offering extremely high cost-effectiveness and engineering application value.

[0059] ESR is the equivalent resistance that measures all inherent losses in the conductive path of a capacitor. In the totem-pole PFC circuit of this embodiment, the switching transistor operates at a high frequency (typically tens to hundreds of kHz), generating a large high-frequency ripple current on the DC bus. This current flows entirely or primarily through the third capacitor C3, which performs the main filtering task. According to Joule's law, P_loss = I_ripple² ESR (Electrostatic Discharge Ratio) is the heat loss that occurs when ripple current flows through the ESR of a capacitor. Strictly limiting the ESR to a low level of less than 50mΩ can significantly reduce this conduction loss. This is crucial for totem-pole PFC topologies that prioritize high efficiency, directly contributing to improved overall power conversion efficiency and meeting the energy efficiency standards of high-end power equipment (such as data center power supplies).

[0060] The lifespan of electrolytic capacitors is extremely sensitive to their internal core temperature. The widely accepted "10°C rule" states that for every 10°C decrease in operating temperature, the expected lifespan can approximately double. Heat generated by P_loss is one of the main causes of capacitor temperature rise. Using capacitors with ESR < 50mΩ reduces heat generation at the source, thereby significantly lowering the steady-state operating temperature of the capacitor and ensuring the stability and reliability of the high-frequency filtering performance of the third capacitor, C3.

[0061] In addition, a lower ESR means that the capacitor has a lower impedance at high frequencies, which can more effectively "absorb" or "short-circuit" the switching frequency and its harmonic noise, helping to output a cleaner DC voltage and also better improve filtering performance, thereby better suppressing DC bus voltage ripple.

[0062] The use of electrolytic capacitors in this embodiment ensures the feasibility of the solution in terms of capacity, size, and cost; while the mandatory requirement of "ESR < 50mΩ" better achieves high-level technical indicators such as high efficiency, low temperature rise, and long lifespan. The combination of these two aspects allows this totem-pole PFC circuit to not only solve the inherent defect of reduced equivalent capacitance of series capacitors, but also optimize key performance aspects such as efficiency and reliability, thus providing crucial technical support for the development of high-efficiency, high-reliability power supply products.

[0063] In one exemplary embodiment, reference Figure 1 and Figure 2 As shown, a totem pole power factor correction (PFC) circuit is provided, as well as a power supply system equipped with the totem pole PFC circuit, which can be applied to data centers.

[0064] In this embodiment, the rated output power of the power supply system is 1kW, and the rated input of the power supply system is 230V AC. For example, it can be a power supply system with a 1kW AC input (230V AC, 50Hz).

[0065] It should be noted that in related technologies, the capacitor module 10 of the totem pole PFC circuit generally adopts a series capacitor structure. For example, the first capacitor C1 and the second capacitor C2 are both standard electrolytic capacitors with a capacitance of 100μF and a withstand voltage of 250V. The equivalent capacitance after series connection is C_eq1 = (100μF) (100μF) / (100μF + 100μF) = 50μF. In this embodiment, a parallel branch is set at both ends of the aforementioned series branch (i.e., the positive and negative terminals of the DC bus). The parallel branch may include a third capacitor C3, whose capacitance value (i.e., capacity) can be precisely set as C3 = C_eq1. That is, the capacitance value of the third capacitor C3 can be the sum of the capacitance values ​​of the first capacitor C1 and the second capacitor C2, i.e., the capacitance value of the third capacitor C3 can be 200μF. Specifically, the third capacitor C3 can be a low-ESR electrolytic capacitor (250V withstand voltage, ESR < 50mΩ) to ensure high-frequency filtering performance.

[0066] In the totem-pole PFC circuit of this embodiment, the inductor module L (L = 200μH) is placed between the rectifier module 20 and the AC power supply; one end of the switching module SW (MOSFET switch) is connected to the AC input terminal, and the other end is connected to the connection point of the first capacitor C1 and the second capacitor C2; the switching module SW has two states: on and off. When the switching module SW is on, the positive terminal of the third unidirectional conduction unit D3 is connected to the connection point of the first capacitor C1 and the second capacitor C2; when the switching module SW is off, the positive terminal of the third unidirectional conduction unit D3 is disconnected from the connection point of the first capacitor C1 and the second capacitor C2. The control module may include a parameter detection unit (monitoring the current / voltage of the load 30) and a main control unit (based on PWM signal switching mode).

[0067] The rectifier module 20 includes a first unidirectional conducting unit D1, a second unidirectional conducting unit D2, a third unidirectional conducting unit D3, a fourth unidirectional conducting unit D4, a first switching unit Q1, a second switching unit Q2, a third switching unit Q3, and a fourth switching unit Q4. The unidirectional conducting units are connected in a bridge configuration, meaning the positive terminal of the first unidirectional conducting unit D1 is connected to the negative terminal of the second unidirectional conducting unit D2, the positive terminal of the third unidirectional conducting unit D3 is connected to the negative terminal of the fourth unidirectional conducting unit D4, the negative terminal of the first unidirectional conducting unit D1 is connected to the negative terminal of the third unidirectional conducting unit D3, and the positive terminal of the second unidirectional conducting unit D2 is connected to the positive terminal of the fourth unidirectional conducting unit D4. Each unidirectional conduction unit is connected in parallel with a switching unit, meaning that the first unidirectional conduction unit D1 is connected in parallel with the first switching unit Q1, the second unidirectional conduction unit D2 is connected in parallel with the second switching unit Q2, the third unidirectional conduction unit D3 is connected in parallel with the third switching unit Q3, and the fourth unidirectional conduction unit D4 is connected in parallel with the fourth switching unit Q4.

[0068] In this embodiment, in the rectifier module 20 composed of devices such as the first unidirectional conduction unit D1 and the first switching unit Q1, the negative terminal of the first unidirectional conduction unit D1 and the positive terminal of the second unidirectional conduction unit D2 are the output terminals of the rectifier module 20, and the positive terminals of the first unidirectional conduction unit D1 and the third unidirectional conduction unit D3 are the input terminals of the rectifier module 20.

[0069] The following is a verification of the effectiveness of the work mode: 1. Synchronous rectification mode (full load condition, load parameter 30 in the second operating range): When the switching module SW is turned on, the third capacitor C3 quickly absorbs the transient current of the switch (such as the current spike when the first switching unit Q1 / second switching unit Q2 is turned on), so that the voltage fluctuation of the first capacitor C1 and the second capacitor C2 is reduced from ±3.0V in the original scheme to ±0.4V.

[0070] The parameter detection unit accurately detects 30 load parameters (such as current 10A). The main control unit maintains the first switch unit Q1 and the second switch unit Q2 synchronously on (when the first unidirectional conduction unit D1 and the second unidirectional conduction unit D2 are on, the first switch unit Q1 and the second switch unit Q2 are on, and vice versa), to avoid mode misjudgment caused by voltage imbalance between the first capacitor C1 and the second capacitor C2.

[0071] Results: Input current THD decreased from 12.5% ​​to 3.8%, and power factor (PF) stabilized at 0.993, meeting the IEC61000-3-2 Class A standard.

[0072] 2. High-frequency switching mode (light load condition, load parameter 30 in the first operating range): When the switching module SW is turned on, the third capacitor C3, along with the first capacitor C1 and the second capacitor C2, work together to smooth the inductor current ripple. The PWM signal duty cycle is dynamically adjusted based on the AC voltage waveform (e.g., the third switching unit Q3 is turned off and the fourth switching unit Q4 is turned on during the positive half-cycle). The third capacitor C3 reduces the DC bus voltage ripple from 8.2V in the original scheme to 1.6V.

[0073] Results: Within a load range of 20%-100% (30V), power factor (PF) is consistently greater than 0.99, resulting in a 2.3% efficiency improvement (actual full-load efficiency of 97.1% vs. the original solution of 94.8%). Voltage fluctuations during mode switching are reduced by 92% (from ±4.5V to ±0.35V), and the control module exhibits no oscillation.

[0074] In this embodiment, when the third capacitor C3 is 200μF, the total equivalent capacitance of the parallel and series branches is increased by 5 times compared to the equivalent capacitance of the series branch: C_total = C_eq1 + C_eq2 = 50μF + 200μF = 250μF, ripple voltage The cost is reduced by 80%. In addition, this embodiment eliminates the need to purchase high-capacitance capacitors (in the original solution, to achieve the required ripple suppression effect, the first capacitor C1 and the second capacitor C2 need to be 400μF / 250V capacitors, which increases the cost by 35%). In this embodiment, the third capacitor C3 can be a standard 200μF / 250V capacitor, reducing material costs by 32%.

[0075] The third capacitor C3 in this embodiment suppresses electromagnetic interference (EMI) radiation (reducing conducted EMI by 12dB), maintains stable voltage fluctuations within a temperature range of -40℃ to +85℃, and has passed a 5000-hour aging test. This implementation addresses industry pain points with minimal structural modifications (adding only one third capacitor C3). Real-world testing shows a power factor (PF) > 0.99 and a total electrical discharge voltage (THD) < 5% over a wide load range of 30V, and it is compatible with existing totem-pole control logic. Its economic efficiency (cost increase < 5%) and performance improvement (efficiency + 2.3%) make it the optimal implementation solution for industrial-grade PFC circuits. It has been successfully applied to data center power systems (1kW / 230V AC input), with no failure cases verified in experiments.

[0076] In one exemplary embodiment, reference Figure 1 and Figure 2 As shown, a totem pole power factor correction (PFC) circuit is provided, as well as a compressor equipped with the totem pole PFC circuit and an air conditioning unit equipped with the compressor.

[0077] In this embodiment, the totem-pole PFC circuit is connected sequentially to the inverter 31 and the motor 32. The totem-pole PFC circuit outputs a drive signal to the inverter 31, which drives the motor 32 to operate. The motor 32 can be used as a compressor, which can be used as an air conditioning unit. That is, the load 30 driven by the totem-pole PFC circuit in this embodiment can be clearly defined as the inverter 31 and the motor 32. The compressor in this embodiment has the advantages of the totem-pole PFC circuit in the previous embodiment, namely, improved current harmonics and power factor. It can also switch between synchronous rectification mode and high-frequency switching mode depending on the load on the motor 32, thereby adapting to different voltage requirements under different loads by selecting boost and voltage multiplication, while maintaining the high efficiency advantage of the PFC circuit.

[0078] For example, the structure of the totem-pole PFC circuit, as described in other embodiments, includes a rectifier module 20, an inductor module L, a capacitor module 10 with series and parallel branches, a switch module SW, and a control module. Its AC input terminal can be connected to mains power. The DC input terminal of the inverter 31 is directly connected to the DC output terminal of the totem-pole PFC circuit (i.e., the positive and negative buses of the capacitor module 10). The inverter 31 is generally composed of six IGBT or MOSFET power switches in a three-phase full-bridge configuration. The motor 32 can be a permanent magnet synchronous motor 32 or an induction motor 32, with its three-phase input terminal connected to the three-phase AC output terminal of the inverter 31. The motor 32 serves as the power core of the compressor, integrated into or directly driving the compressor's scroll plate or rotor, thus forming a variable frequency compressor. This variable frequency compressor, as the core cooling / heating component of the air conditioning equipment, is installed in the outdoor unit of the air conditioning equipment (such as a multi-split system or a household variable frequency air conditioner).

[0079] In this embodiment, the load 30 to be driven by the totem pole PFC circuit is specifically the subsequent inverter 31 and motor 32. The PFC circuit converts the unstable AC mains power into stable, low-ripple DC power to supply the inverter 31; under the command of the air conditioner main controller, the inverter 31 inverts the DC power into three-phase AC power with variable voltage and variable frequency, thereby precisely driving the motor 32 to operate at variable speed, and ultimately controlling the refrigerant discharge of the compressor.

[0080] In this embodiment, the control module's operating logic of the totem-pole PFC circuit is deeply coupled with the characteristics of the load 30 that drives the compressor. Specifically, the parameter detection unit in the control module monitors the operating parameters of the load 30 in real time. These "load 30 parameters" can directly represent the compressor's required speed or the estimated torque / power of the motor 32. For example, when the air conditioning system needs rapid cooling, the compressor needs to operate at high frequency and high load; when the room temperature is close to the set temperature, the compressor operates at low frequency and light load.

[0081] When the compressor is detected to be operating under high load (corresponding to high power demand from motor 32 and a need for higher voltage from the DC bus), the control module switches the PFC circuit to high-frequency switching mode (boost mode). In this mode, the circuit actively performs boost conversion, raising the DC bus voltage to a stable level higher than the peak value of the AC input (e.g., approximately 400V DC) to meet the voltage requirements of the inverter 31 driving the high-power output of motor 32, while maintaining an extremely high input power factor.

[0082] When the compressor is detected to be operating under low load or light load conditions (such as low-frequency sustained operation), the control module can switch it to synchronous rectification mode (voltage doubling / buck mode). In this mode, the circuit is equivalent to a rectifier with extremely low conduction losses. While meeting lower voltage requirements, it can maximize light-load efficiency and avoid unnecessary switching losses.

[0083] In this embodiment, thanks to the strong suppression of DC bus voltage ripple by the capacitors in the parallel branches of the totem-pole PFC circuit (ripple reduction of approximately 80%), an extremely clean DC power supply is provided to the downstream inverter 31. This results in higher quality current waveform output from inverter 31 to motor 32, reduced motor losses, and decreased torque fluctuations. Throughout the compressor's operating range from 20% light load to 100% full load, the input-side power factor (PF) of the air conditioning system remains above 0.99, far exceeding energy efficiency standards and reducing harmonic pollution to the power grid (THD < 5%). Furthermore, the improved efficiency of the totem-pole PFC circuit itself (e.g., full-load efficiency reaching 97.1%), combined with optimization of the downstream drive, directly improves the annual power efficiency (APF) of the air conditioner.

[0084] In this embodiment, the totem-pole PFC circuit can seamlessly and intelligently switch between high-frequency switching mode and synchronous rectification mode according to the compressor load 30. This ensures that the front-end power supply circuit always operates in the optimal efficiency range, whether the air conditioning system is under high load conditions requiring strong cooling / heating or under light load conditions maintaining temperature. This eliminates the problem of low efficiency of traditional single-mode PFC under light loads and significantly expands the high-efficiency operating range.

[0085] Furthermore, the low-ripple DC bus in this embodiment reduces the voltage stress on the power devices of inverter 31, improving long-term reliability. The totem-pole PFC circuit itself reduces conducted EMI by 12dB, making it easier for the entire air conditioning unit to pass electromagnetic compatibility certification, reducing interference to surrounding equipment, and also reducing control signal noise within the system.

[0086] This embodiment eliminates the need for expensive high-voltage, high-capacity capacitors or additional filtering components in the compressor drive system. Its "standard capacitor series + low-cost capacitor parallel" structure achieves a leap in power quality with minimal (<5%) increase in material costs. The circuit is fully compatible with common inverter compressor drive architectures, requiring no modification to the main control logic, and is easily and quickly implemented on existing air conditioning product platforms. It represents a key technological optimization for achieving high-end and high-efficiency air conditioning.

[0087] In other words, this embodiment deeply integrates the high-performance totem-pole PFC circuit with the variable frequency compressor drive, enabling the air conditioning equipment to achieve a systematic improvement in key indicators such as input power factor, overall energy efficiency, light load performance, operational reliability and electromagnetic compatibility, thus significantly enhancing product competitiveness at a minimal cost.

[0088] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0089] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0090] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A totem-pole power factor correction circuit, characterized by, The totem column power factor correction circuit comprises: a rectifier module, an input end of which is connected to an AC power supply, and an output end of which is connected to a load; an inductor module, which is connected in series between the AC power supply and the input end of the rectifier module; a capacitor module, which is connected in parallel to the output end of the rectifier module, and comprises a series branch and a parallel branch, the series branch comprises a first capacitor and a second capacitor connected in series, and the parallel branch comprises at least one third capacitor, the parallel branch being connected in parallel across the series branch; a switch module, one end of which is connected to one input end of the rectifier module, and the other end of which is connected to a connection point of the first capacitor and the second capacitor; a control module, which is configured to control the rectifier module and the switch module to operate in a high-frequency switching mode or a synchronous rectification mode according to an operating parameter of the load.

2. The totem-pole power factor correction circuit of claim 1, wherein, An equivalent capacitance of the parallel branch is greater than or equal to an equivalent capacitance of the first capacitor and the second capacitor connected in series.

3. The totem column power factor correction circuit according to claim 1, wherein: the parallel branch comprises an electrolytic capacitor with an equivalent series resistance less than 50 mΩ.

4. The totem column power factor correction circuit according to claim 1, wherein: the first capacitor and the second capacitor have the same capacitance value; and / or the first capacitor and the second capacitor have the same withstand voltage value.

5. The totem column power factor correction circuit according to claim 1, wherein: when the totem column power factor correction circuit is applied to a power supply system with a rated output power of 1 kW and a rated input of 230 V AC: the first capacitor has a capacitance value greater than or equal to 100 μF and a withstand voltage value greater than or equal to 250 V; and / or the second capacitor has a capacitance value greater than or equal to 100 μF and a withstand voltage value greater than or equal to 250 V.

6. The totem-pole power factor correction circuit according to any one of claims 1-5, characterized in that, The totem column power factor correction circuit is configured such that, when the load is in a range of 20% to 100%, the power factor of the totem column power factor correction circuit is greater than 0.

99.

7. A power system of a data center, characterized by, The power supply system comprises the totem column power factor correction circuit according to any one of claims 1 to 6.

8. The power system of claim 7, wherein, The power supply system has a rated output power of 1 kW, and the rated input of the power supply system is 230 V AC.

9. A compressor characterized by, The compressor comprises: the totem column power factor correction circuit according to any one of claims 1 to 6; an inverter, an input end of which is connected to the output end of the rectifier module in the totem column power factor correction circuit; a motor, which is connected to an output end of the inverter.

10. An air conditioning apparatus characterized by comprising: The air conditioning equipment comprises the compressor according to claim 9.

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