Power factor correction circuit, control system and power supply equipment

Abstract

The present application relates to a power factor correction circuit, a control system, and a power supply device. The power factor correction circuit includes an input bus, at least two power factor correction branches connected in parallel to the input bus, and a filter capacitor and a load connected in parallel at both ends of the input bus. Each power factor correction branch includes an energy storage inductor and a switch tube and a diode connected to the energy storage inductor. The switch tube and the diode are also connected to the filter capacitor and the load, respectively. The input bus is used to connect to the input power supply. The present application can reduce the capacity of a single energy storage inductor, reduce the average current stress and output current ripple of the switching device, extend the life of the switching device, reduce the cost of the power supply device, and improve the working efficiency of the power supply device.

Description

Technical Field

[0001] The present application belongs to the technical field of power supply circuits, and specifically relates to a power factor correction circuit, a control system, and a power supply device. Background Art

[0002] Power factor correction (PFC) refers to the relationship between active power and total power, or the ratio of effective power to total power. Power factor measures the degree to which electricity is effectively utilized; a higher power factor value indicates higher power utilization. Power factor correction circuits are widely used in high-power AC-to-DC power supplies. With the continued development of electric vehicles and backup energy storage battery stations, the power required by AC power supply equipment is also increasing, limiting the use of traditional single-stage power factor correction circuit structures. As power increases, the switching devices in a single-stage power factor correction circuit must withstand greater current and voltage stress. During the switching process, excessive current and voltage stress at key nodes in the circuit can cause severe radiation and electromagnetic interference (EMI). Furthermore, when the power of the power factor correction circuit is relatively high, such as exceeding 10kW, the use of a separate inductor as a magnetic structure results in a larger inductor volume and higher losses, increasing the overall cost of the power supply equipment. Summary of the Invention

[0003] In order to at least to some extent overcome the problems that the switching devices of a single-stage power factor correction circuit are subjected to excessive current stress and voltage stress, which are easily damaged and cause serious radiation and electromagnetic interference, as well as the problems that the inductor volume is too large and the power supply equipment cost is relatively high, the present application provides a power factor correction circuit, a control system and a power supply equipment.

[0004] In a first aspect, the present application provides a power factor correction circuit, comprising:

[0005] An input bus, at least two power factor correction branches connected in parallel to the input bus, and a filter capacitor and a load connected in parallel at both ends of the input bus;

[0006] Each power factor correction branch includes an energy storage inductor and a switch tube and a diode connected to the energy storage inductor, and the switch tube and the diode are also connected to the filter capacitor and the load respectively;

[0007] The input bus is used to connect the input power supply. When the switch tube in a power factor correction branch is turned on, the input power supply, the energy storage inductor connected to the turned-on switch tube, and the turned-on switch tube form a power supply circuit. At this time, the energy storage inductor connected to the turned-on switch tube stores energy, and the filter capacitor supplies power to the load.

[0008] When the switch tube in the power factor correction branch is turned off, the input power supply, the energy storage inductor connected to the turned-off switch tube, the diode, the filter capacitor and the load form a power supply circuit. The input power supply and the energy storage inductor connected to the turned-off switch tube supply power to the load and charge the filter capacitor at the same time.

[0009] Furthermore, the number of the power factor correction branches is an even number and is greater than or equal to 2.

[0010] Furthermore, when the switch tube is turned on, the current and voltage of the corresponding power factor correction branch increase with the turn-on time, and when the switch tube is turned off, the current and voltage of the corresponding power factor correction branch decrease with the turn-off time.

[0011] Furthermore, the switch tube is a MOSFET.

[0012] In a second aspect, the present application provides a power factor correction control system, comprising:

[0013] A power factor correction circuit as described in the first aspect.

[0014] Furthermore, it also includes:

[0015] At least one controller is connected to the switch tubes in one or more power factor correction branches.

[0016] Furthermore, it also includes:

[0017] The at least one controller is used to control multiple switching tubes to be turned on in sequence within a working cycle T of the power factor correction circuit, so that the conduction time of each switching tube is 1 / T.

[0018] Furthermore, it also includes:

[0019] The number of controllers is half the number of the power factor correction branches. The working cycle T of the power factor correction circuit includes multiple conduction time periods. Each controller controls the conduction time of the switch tube connected to the controller to be 1 / T within the corresponding conduction time period.

[0020] Furthermore, it also includes:

[0021] During a conduction time period, in two power factor correction branches connected to a controller, the energy storage inductor connected to the conducted switch tube is in an energy storage state, and the energy storage inductor connected to the non-conducting switch tube is in a discharge state.

[0022] In a third aspect, the present application provides a power supply device, comprising:

[0023] A power factor correction control system as described in the second aspect.

[0024] The technical solutions provided by the embodiments of the present application may have the following beneficial effects:

[0025] The power factor correction circuit, control system and power supply equipment provided by the embodiments of the present invention include an input bus, at least two power factor correction branches connected in parallel to the input bus, and a filter capacitor and a load connected in parallel at both ends of the input bus. Each power factor correction branch includes an energy storage inductor and a switch tube and a diode connected to the energy storage inductor. The switch tube and the diode are also connected to the filter capacitor and the load respectively. The input bus is used to connect the input power supply. When the switch tube in a power factor correction branch is turned on, the input power supply, the energy storage inductor connected to the turned-on switch tube, and the load are connected to the filter capacitor and the load respectively. The inductor and the on-state switch tube form a power supply circuit. At this time, the energy storage inductor connected to the on-state switch tube stores energy, and the filter capacitor supplies power to the load. When the switch tube in the power factor correction branch is turned off, the input power supply, the energy storage inductor connected to the off-state switch tube, the diode, the filter capacitor and the load form a power supply circuit. The input power supply and the energy storage inductor connected to the off-state switch tube supply power to the load and charge the filter capacitor at the same time, reducing the capacity of a single energy storage inductor, and can reduce the average current stress and output current ripple of the switching device, extend the life of the switching device, reduce the cost of the power supply equipment, and improve the working efficiency of the power supply equipment.

[0026] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0028] Figure 1 A power factor correction circuit is provided in accordance with an embodiment of the present application.

[0029] Figure 2 A circuit diagram of a traditional single-stage power factor correction circuit provided in one embodiment of the present application.

[0030] Figure 3 A functional structure diagram of a power factor correction control system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be described in detail below. Obviously, the embodiments described are only some of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other implementation methods obtained by ordinary technicians in this field without making any creative work are within the scope of protection of this application.

[0032] Figure 1 A circuit diagram of a power factor correction circuit provided in one embodiment of the present application is shown in FIG. Figure 1 As shown, the power factor correction circuit includes:

[0033] Input bus, at least two power factor correction branches connected in parallel to the input bus, and a filter capacitor C connected in parallel at both ends of the input bus o and load R;

[0034] Each power factor correction branch includes an energy storage inductor and a switch tube and a diode connected to the energy storage inductor. The switch tube and the diode are also connected to the filter capacitor C o Connected to load R;

[0035] For example, Figure 1 As shown, the energy storage inductor L1 is connected to the switch tube Q1 and the diode D1, the energy storage inductor L2 is connected to the switch tube Q2 and the diode D2, ..., the energy storage inductor L6 is connected to the switch tube Q6 and the diode D6;

[0036] The input bus is used to connect the input power supply. When the switch tube in a power factor correction branch is turned on, the input power supply, the energy storage inductor connected to the turned-on switch tube, and the turned-on switch tube form a power supply circuit. At this time, the energy storage inductor connected to the turned-on switch tube stores energy, and the filter capacitor supplies power to the load.

[0037] When the switch tube in the power factor correction branch is turned off, the input power supply, the energy storage inductor connected to the cut-off switch tube, the diode, the filter capacitor and the load form a power supply circuit. The input power supply and the energy storage inductor connected to the cut-off switch tube supply power to the load and charge the filter capacitor at the same time.

[0038] In this embodiment, the number of power factor correction branches is an even number and is greater than or equal to 2.

[0039] When a switch (e.g., a MOSFET) is on, the current and voltage in the corresponding power factor correction branch increase with the on-time. When the switch is off, the current and voltage in the corresponding power factor correction branch decrease with the off-time. When the switch is on, the current in the corresponding branch increases with the on-time. When the switch is off, the current decreases with the off-time. Therefore, the current stress on each branch is less than when the circuit is continuously on in a single-stage structure.

[0040] The use of traditional single-stage power factor correction circuit structure is limited. Figure 2 As shown in the figure, the single-stage power factor correction circuit consists of an energy storage inductor L, a switching tube Q, a diode D, an output filter capacitor C, and a load R. The operating principle of this converter can be divided into two modes: on and off, depending on the on and off of the switching tube Q. When Q is on, the diode D and the part of the circuit after it are short-circuited, and the DC power supply, energy storage inductor L, and MOSFET form a loop. At this time, the energy storage inductor L stores energy, and the load R is powered by the filter capacitor C. When Q is off, the DC power supply, energy storage inductor L, diode D, filter capacitor C, and load R form a loop. At this time, the DC power supply and energy storage inductor L together supply power to the load R and charge the filter capacitor C at the same time. In this operating mode, the energy storage inductor L releases energy, there are two energy sources in the loop, and the output voltage is greater than the DC power supply voltage. As power increases, the switch tube Q of the single-stage power factor correction circuit must withstand greater current stress and voltage stress. During the switching process between the on and off modes, the switch tube Q will experience excessive current stress and voltage stress, which will cause serious radiation and electromagnetic interference. In addition, when the power of the power factor correction circuit is relatively large, such as exceeding 10kW, the capacity of the energy storage inductor L of the power factor correction circuit must also be increased. Therefore, the inductor volume will be relatively large, and the loss when storing or releasing energy will also be relatively high, resulting in an overall increase in the cost of the power supply equipment.

[0041] In this embodiment, the power factor correction circuit includes an input bus, at least two power factor correction branches connected in parallel to the input bus, and a filter capacitor and a load connected in parallel at both ends of the input bus. Each power factor correction branch includes an energy storage inductor, a switch tube and a diode connected to the energy storage inductor, and the switch tube and the diode are also connected to the filter capacitor and the load, respectively. The input bus is used to connect to an input power supply. When the switch tube in a power factor correction branch is turned on, the input power supply, the energy storage inductor connected to the turned-on switch tube, and the turned-on switch tube form a power supply circuit. At this time, the energy storage inductor connected to the turned-on switch tube stores energy, and the filter capacitor supplies power to the load. When the switch tube in the power factor correction branch is turned off, the input power supply, the energy storage inductor connected to the turned-off switch tube, the diode, the filter capacitor, and the load form a power supply circuit. The input power supply and the energy storage inductor connected to the turned-off switch tube supply power to the load and simultaneously charge the filter capacitor, thereby reducing the capacity of a single energy storage inductor, reducing the average current stress and output current ripple of the switching device, extending the life of the switching device, reducing the cost of the power supply equipment, and improving the operating efficiency of the power supply equipment.

[0042] Figure 3 This is a functional structure diagram of a power factor correction control system provided by an embodiment of the present application, such as Figure 3As shown, the power factor correction control system includes:

[0043] The power factor correction circuit 31 as described in the above embodiment.

[0044] In this embodiment, the power factor correction control system further includes:

[0045] At least one controller 32 is connected to the switch tubes in one or more power factor correction branches.

[0046] At least one controller is used to control multiple switching tubes to be turned on in sequence within a working cycle T of the power factor correction circuit, so that the conduction time of each switching tube is 1 / T.

[0047] For example, in a power factor correction system with N (N≥2, N is an even number) stages of staggered parallel power factor correction branches, each power factor correction branch is turned on separately by a controller, which is equivalent to each stage of the power factor correction circuit being turned on in turn for 1 / N of the time within a power factor correction circuit working cycle T, thereby equally allocating the power output to each power factor correction branch. Each power factor correction branch works in an staggered manner, thereby reducing the current stress and voltage stress on each power factor correction branch, effectively reducing EMI noise; the high input power factor increases the power density of the system and greatly improves the power of the equipment.

[0048] In some embodiments, the number of controllers is half the number of power factor correction branches, the power factor correction circuit working cycle T includes multiple conduction time periods, and each controller controls the conduction time of the switch tube connected to the controller to be 1 / T during the corresponding conduction time period.

[0049] When a single control chip cannot meet the requirements, multiple controller chips can be used to coordinate their operation. Let M be the number of controllers (M = N / 2), designated U1, U2, ..., and UM. Each controller controls two power factor correction branches, with staggered conduction. Each branch's conduction time is 1 / N of the total system's. During the 0-T1 period, U1 controls the staggered conduction of the first and second power factor correction branches. During the T1-T2 period, U2 controls the staggered conduction of the third and fourth power factor correction branches. ..., UM controls the staggered conduction of the N-1st and Nth power factor correction branches. Therefore, an N-stage parallel power factor correction system improves input power factor and effectively reduces EMI noise. Compared to a single-stage power factor correction system at the same power output, the current stress on each branch is reduced, reducing the size of the energy storage inductor, increasing the system's power density, and significantly improving device power. Furthermore, using multiple controllers for coordinated control enables intelligent regulation and improves system efficiency.

[0050] In this embodiment, multiple controllers are used to control the power factor correction, thereby realizing intelligent control and improving circuit operating efficiency.

[0051] In this embodiment, during a conduction time period, in two power factor correction branches connected to a controller, the energy storage inductor connected to the conducted switch tube is in an energy storage state, and the energy storage inductor connected to the non-conducting switch tube is in a discharge state.

[0052] The current ripples output by the energy storage inductor in the energy storage state and the energy storage inductor in the discharge state cancel each other out, which can reduce the average current stress and output current ripple of the switching device.

[0053] In this embodiment, an N-stage parallel power factor correction circuit structure is adopted, and multiple circuits are staggered in parallel. Compared with a single-stage power factor correction system under the same power, the current stress borne by each circuit is reduced, the volume of the energy storage inductor is reduced, the power density of the system is increased, and the power of the equipment is greatly improved. At the same time, multiple controllers can be used to intelligently control the power factor correction system to improve the circuit working efficiency.

[0054] An embodiment of the present invention provides a power supply device, including: the power factor correction control system as described in the above embodiment.

[0055] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0056] It should be noted that, in the description of this application, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0057] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0058] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0059] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0060] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0061] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0062] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0063] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

[0064] It should be noted that the present invention is not limited to the above-mentioned optimal embodiment. Those skilled in the art can derive other forms of products under the guidance of the present invention. However, no matter what changes are made in their shape or structure, all technical solutions that are the same or similar to those of the present application fall within the scope of protection of the present invention.

Claims

1. A power factor correction circuit, characterized in that: include: An input bus, at least two power factor correction branches connected in parallel to the input bus, and a filter capacitor and a load connected in parallel at both ends of the input bus; Each power factor correction branch includes an energy storage inductor and a switching tube and a diode connected to the energy storage inductor, and the switching tube and the diode are also connected to the filter capacitor and the load respectively; the switching tube is also connected to a controller so that the controller controls multiple switching tubes to be turned on in sequence within a power factor correction circuit working cycle T, so that each switching tube is turned on in sequence for 1 / N of the working cycle T, that is, T / N time, within the power factor correction circuit working cycle T; the number of controllers is half the number of the power factor correction branches, each controller controls two power factor correction branches, and staggered conduction, the power factor correction circuit working cycle T includes multiple conduction time periods, and each controller controls the switching tube connected to the controller in the corresponding conduction time period so that within the power factor correction circuit working cycle T, each power factor correction circuit is turned on in sequence for 1 / N of the working cycle T, that is, T / N time; The input bus is used to connect the input power supply. When the switch tube in a power factor correction branch is turned on, the input power supply, the energy storage inductor connected to the turned-on switch tube, and the turned-on switch tube form a power supply circuit. At this time, the energy storage inductor connected to the turned-on switch tube stores energy, and the filter capacitor supplies power to the load. When the switch in the power factor correction branch is turned off, the input power supply, the energy storage inductor connected to the turned-off switch, the diode, the filter capacitor, and the load form a power supply circuit. The input power supply and the energy storage inductor connected to the turned-off switch supply power to the load and charge the filter capacitor at the same time. The number of the power factor correction branches is an even number and is greater than or equal to 2; The controller is also used to control: during the process of staggered conduction of the two power factor correction branches controlled by one controller, when the switch tube of one power factor correction branch is turned on to store energy in its energy storage inductor, the switch tube of the other power factor correction branch is turned off to discharge energy in its energy storage inductor.

2. The power factor correction circuit according to claim 1, characterized in that: When the switch tube is turned on, the current and voltage of the corresponding power factor correction branch increase with the turn-on time, and when the switch tube is turned off, the current and voltage of the corresponding power factor correction branch decrease with the turn-off time.

3. The power factor correction circuit according to claim 1 or 2, characterized in that: The switch tube is a MOSFET.

4. A power factor correction control system, characterized in that: include: The power factor correction circuit according to any one of claims 1 to 3; At least one controller, wherein the at least one controller is connected to the switch tubes in one or more power factor correction branches; The at least one controller is used to control the plurality of switching tubes to be turned on in sequence within a working cycle T of the power factor correction circuit, so that each switching tube is turned on in sequence for 1 / N of the working cycle T, that is, T / N, within the working cycle T of the power factor correction circuit. The number of controllers is half the number of the power factor correction branches. Each controller controls two power factor correction branches so that the two power factor correction branches are turned on alternately. The power factor correction circuit working cycle T includes multiple conduction time periods. Each controller controls the switch tube connected to the controller during the corresponding conduction time period. Within one power factor correction circuit working cycle T, each stage of the power factor correction circuit is turned on in turn for 1 / N of the working cycle T, that is, T / N time.

5. A power supply device, characterized in that: include: The power factor correction control system as claimed in claim 4.

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