Power supply circuit capable of improving PF and THD values of PFC circuit

Abstract

The utility model discloses a power supply circuit capable of improving PF and THD values of a PFC circuit. The power supply circuit comprises an input rectification filtering module, an input voltage detection module, a compensation boost control module, a PFC power control module, a PFC power level module, a PFC voltage detection module and a PFC output module. Through the structure, the reference voltage and the input voltage can be used for sampling again, when the input voltage reaches a certain value, feedback parameters of a PFC boost loop are changed, the PFC works in a continuous driving mode, the purpose of improving PFC and THD values is achieved, and the stability of the switching power supply is improved.

Description

Technical Field

[0001] The utility model relates to the field of switching power supplies, in particular to a power supply circuit capable of improving PF and THD values ​​of a PFC circuit. Background Art

[0002] With the continuous development of components and power electronics technology, switching power supply technology has achieved rapid development and has quickly grown into an important basic product of the electronics industry. Switching power supplies have the advantages of miniaturization, light weight, and high conversion efficiency, and have quickly become mainstream power products; in order to better utilize energy, switching power supplies generally sample active power factor correction circuits, but when the rated input voltage is high, it will cause the PFC value to decrease and the harmonic value THD to increase, resulting in input current waveform distortion; therefore, a power supply circuit that can improve the PF and THD values ​​of the PFC circuit is urgently needed to solve the above problems. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a power supply circuit which can improve the PF and THD values ​​of a PFC circuit.

[0004] An embodiment of the utility model adopts a technical solution to solve its technical problem: a power supply circuit capable of improving the PF and THD values ​​of a PFC circuit, comprising an input rectifier filter module, an input voltage detection module, a compensation boost control module, a PFC power control module, a PFC power level module, a PFC voltage detection module and a PFC output module;

[0005] The input rectifier and filter module is respectively connected to the external power supply, the input voltage detection module and the PFC power stage module;

[0006] The first comparison terminal of the compensation boost control module is connected to the input voltage detection module, and the second comparison terminal is connected to the reference voltage;

[0007] The PFC power control module is respectively connected to the output end of the compensation boost control module, the PFC power stage module and the PFC voltage detection module;

[0008] The PFC output module is connected to the PFC power stage module and the PFC voltage detection module respectively;

[0009] The compensation boost control module can control the PFC power control module to increase the PFC output voltage when the input voltage detection module detects that the input voltage increases to a preset value.

[0010] As one of the preferred embodiments of the utility model, the input voltage detection module includes a diode D3, resistors R4-6, a capacitor C1, a capacitor C4 and a Zener diode ZD1. The anode of the diode D3 is connected to the input rectifier and filter module, the cathode of the diode D3 is respectively connected to one end of the capacitor C1 and one end of the resistor R4, the other end of the resistor R4 is respectively connected to one end of the capacitor C4, one end of the resistor R6, one end of the Zener diode ZD1 and the first comparison end of the compensation boost control module through the resistor R5, and the other end of the capacitor C4, the other end of the resistor R6, the other end of the Zener diode ZD1 and the other end of the capacitor C1 are grounded.

[0011] As one of the preferred embodiments of the utility model, the compensation boost control module includes a comparator U2, a transistor Q16, a resistor R12 and a capacitor C6, the non-phase input terminal of the comparator U2 is connected to the input voltage detection module, the inverting input terminal of the comparator U2 is connected to the reference voltage, the output terminal of the comparator U2 is connected to the base of the transistor Q16, the power supply terminal of the comparator U2 is connected to VCC1, the collector of the transistor Q16 is respectively connected to one end of the resistor R12 and one end of the capacitor C6, the other end of the resistor R12 and the other end of the capacitor C6 are connected to the PFC power control module, and the emitter of the transistor Q16 is grounded.

[0012] As one of the preferred embodiments of the utility model, the PFC power stage module includes a transformer L1, a MOS tube Q1, a resistor R1 and a resistor R3, one end of the primary winding of the transformer L1 is connected to the input rectifier filter module, the other end of the primary winding of the transformer L1 is connected to the drain of the MOS tube Q1, the source of the MOS tube Q1 is grounded via the resistor R3, and the gate of the MOS tube Q1 is connected to the PFC power control module via the resistor R1.

[0013] As one of the preferred embodiments of the utility model, the PFC voltage detection module includes resistors R14-17 and a capacitor C7, one end of the resistor R14 is connected to the PFC output module, the other end of the resistor R14 is connected to one end of the capacitor C7, one end of the resistor R17 and the PFC power control module through resistors R15 and R16, respectively, and the other end of the capacitor C7 and one end of the resistor R17 are grounded.

[0014] As one of the preferred embodiments of the present utility model, the PFC output module includes a diode D2 and a capacitor CE1, the anode of the diode D2 is connected to the PFC power stage module, the cathode of the diode D2 is respectively connected to one end of the capacitor CE1 and the load, and the other end of the capacitor CE1 is grounded.

[0015] As one of the preferred embodiments of the utility model, a power supply circuit capable of improving the PF and THD values ​​of a PFC circuit further includes a lightning protection module connected to the input rectification and filtering module.

[0016] The beneficial effects of the utility model are as follows: a power supply circuit capable of improving the PF and THD values ​​of a PFC circuit, comprising an input rectifier and filter module, an input voltage detection module, a compensation boost control module, a PFC power control module, a PFC power stage module, a PFC voltage detection module and a PFC output module; the input rectifier and filter module are respectively connected to an external power supply, an input voltage detection module and a PFC power stage module; a first comparison end of the compensation boost control module is connected to the input voltage detection module, and a second comparison end is connected to a reference voltage; the PFC power control module is respectively connected to an output end of the compensation boost control module, a PFC power stage module and a PFC voltage detection module; the PFC output module is respectively connected to the PFC power stage module and the PFC voltage detection module; the compensation boost control module can control the PFC power control module to increase the PFC output voltage when the input voltage detection module detects that the input voltage increases to a preset value; the above structure can utilize the reference voltage and the input voltage to sample again, and when the input voltage reaches a certain value, the PFC boost loop feedback parameter is changed, so that the PFC works in a continuous driving mode, so as to achieve the purpose of improving the PFC and THD values ​​and improve the stability of the switching power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0018] Figure 1 The schematic diagram of a power supply circuit capable of improving the PF and THD values ​​of a PFC circuit is shown in FIG.

[0019] Figure 2 The first part of the circuit schematic diagram of a power supply circuit capable of improving the PF and THD values ​​of a PFC circuit;

[0020] Figure 3 A schematic diagram of the second part of a power supply circuit capable of improving the PF and THD values ​​of a PFC circuit;

[0021] Figure 4 The third part of the circuit schematic diagram of a power supply circuit that can improve the PF and THD values ​​of the PFC circuit. DETAILED DESCRIPTION

[0022] This section will describe in detail the specific embodiments of the utility model. The preferred embodiments of the utility model are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the utility model, but it cannot be understood as a limitation on the protection scope of the utility model.

[0023] In the description of the present utility model, the meaning of "more than" is more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0024] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0025] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0026] Reference Figures 1 to 4 , a power supply circuit capable of improving the PF and THD values ​​of a PFC circuit, comprising an input rectifier filter module 10, an input voltage detection module 20, a compensation boost control module 30, a PFC power control module 40, a PFC power stage module 50, a PFC voltage detection module 60 and a PFC output module 70;

[0027] The input rectification and filtering module 10 is respectively connected to the external power supply, the input voltage detection module 20 and the PFC power stage module 50;

[0028] The first comparison terminal of the compensation boost control module 30 is connected to the input voltage detection module 20, and the second comparison terminal is connected to the reference voltage;

[0029] The PFC power control module 40 is respectively connected to the output end of the compensation boost control module 30 , the PFC power stage module 50 and the PFC voltage detection module 60 ;

[0030] The PFC output module 70 is connected to the PFC power stage module 50 and the PFC voltage detection module 60 respectively;

[0031] The compensation boost control module 30 may control the PFC power control module 40 to increase the PFC output voltage when the input voltage detection module 20 detects that the input voltage increases to a preset value.

[0032] In the present invention, the input end of the input rectifier filter module 10 is connected to the mains or industrial power grid through ACN and ACL, and the input AC power is connected to the mains or industrial power grid through EM After filtering by the common-mode inductor LF1, safety capacitor CX1 and other devices, it is rectified by the rectifier bridge BD1 and then enters the PFC power stage module 50; the input voltage detection module 20 is used to detect and judge the input voltage value. The input voltage detection value is obtained after rectification by the diode D3, filtering by the capacitor C1 and voltage division by the resistors R4-R6, which is used for judgment and comparison by the comparator U2; the reference module 90 is connected to the reference voltage of the circuit and sent to the comparator U2, so as to compare it with the input voltage detection value. The comparator U2 completes the judgment and comparison and sends it to the compensation boost control module 30 for boost compensation control; the compensation boost control module 30 is composed of a resistor R13, a transistor Q16, a resistor R12, etc.; the PFC power control module 40 is composed of a control chip U1 and its peripheral devices; the PFC power stage module 50 is composed of a transformer L1, a MOS tube Q1, etc.; the PFC voltage detection Module 60 is composed of resistors R14-R17, capacitor C7, etc.; PFC output module 70 is composed of diode D2 and capacitor CE1, etc.; its working principle is as follows: as the input AC voltage increases, the input voltage is rectified and filtered, and then compared with the reference voltage. When the input voltage increases to a certain value, the boost compensation boost control module 30 is activated to control the PFC power control module 40 to readjust the PFC output value, increase the PFC output voltage, and adjust the input current waveform phase to follow the input voltage phase, effectively reduce the input current harmonics, and increase the working reliability of the PFC circuit; the advantage of the utility model is that: through the above structure, the reference voltage and the input voltage can be sampled again. When the input voltage reaches a certain value, the PFC boost loop feedback parameters are changed, so that the PFC works in a continuous drive mode, so as to achieve the purpose of improving the PFC and THD values ​​and improve the stability of the switching power supply.

[0033] As a preferred embodiment of the input voltage detection module 20, the input voltage detection module 20 includes a diode D3, resistors R4-6, a capacitor C1, a capacitor C4 and a Zener diode ZD1. The anode of the diode D3 is connected to the input rectifier and filter module 10, and the cathode of the diode D3 is respectively connected to one end of the capacitor C1 and one end of the resistor R4. The other end of the resistor R4 is respectively connected to one end of the capacitor C4, one end of the resistor R6, one end of the Zener diode ZD1 and the first comparison end of the compensation boost control module 30 through the resistor R5. The other end of the capacitor C4, the other end of the resistor R6, the other end of the Zener diode ZD1 and the other end of the capacitor C1 are grounded.

[0034] As a preferred embodiment of the compensation boost control module 30, the compensation boost control module 30 includes a comparator U2, a transistor Q16, a resistor R12 and a capacitor C6, the non-phase input terminal of the comparator U2 is connected to the input voltage detection module 20, the inverting input terminal of the comparator U2 is connected to the reference voltage, the output terminal of the comparator U2 is connected to the base of the transistor Q16, the power supply terminal of the comparator U2 is connected to VCC1, the collector of the transistor Q16 is respectively connected to one end of the resistor R12 and one end of the capacitor C6, the other end of the resistor R12 and the other end of the capacitor C6 are connected to the PFC power control module 40, and the emitter of the transistor Q16 is grounded; wherein the capacitor C6 is connected in parallel to the two ends of the resistor R12, which can improve and stabilize the TDH.

[0035] As a preferred embodiment of the PFC power stage module 50, the PFC power stage module 50 includes a transformer L1, a MOS tube Q1, a resistor R1 and a resistor R3. One end of the primary winding of the transformer L1 is connected to the input rectifier and filter module 10, and the other end of the primary winding of the transformer L1 is connected to the drain of the MOS tube Q1. The source of the MOS tube Q1 is grounded via the resistor R3, and the gate of the MOS tube Q1 is connected to the PFC power control module 40 via the resistor R1.

[0036] As a preferred embodiment of the PFC voltage detection module 60, the PFC voltage detection module 60 includes resistors R14-17 and a capacitor C7, one end of the resistor R14 is connected to the PFC output module 70, the other end of the resistor R14 is connected to one end of the capacitor C7, one end of the resistor R17 and the PFC power control module 40 via resistors R15 and R16, respectively, and the other end of the capacitor C7 and one end of the resistor R17 are grounded.

[0037] As a preferred embodiment of the PFC output module 70, the PFC output module 70 includes a diode D2 and a capacitor CE1, the anode of the diode D2 is connected to the PFC power stage module 50, the cathode of the diode D2 is respectively connected to one end of the capacitor CE1 and the load, and the other end of the capacitor CE1 is grounded.

[0038] A power supply circuit capable of improving the PF and THD values ​​of a PFC circuit further includes a lightning protection module 80 connected to the input rectification and filtering module 10 .

[0039] Of course, the present invention is not limited to the above-mentioned embodiments, and technicians familiar with the field may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A power supply circuit capable of improving the PF and THD values ​​of a PFC circuit, characterized in that: It comprises an input rectification and filtering module (10), an input voltage detection module (20), a compensation boost control module (30), a PFC power control module (40), a PFC power stage module (50), a PFC voltage detection module (60) and a PFC output module (70); The input rectification and filtering module (10) is respectively connected to an external power supply, the input voltage detection module (20) and a PFC power stage module (50); The first comparison terminal of the compensation boost control module (30) is connected to the input voltage detection module (20), and the second comparison terminal is connected to a reference voltage; The PFC power control module (40) is respectively connected to the output end of the compensation boost control module (30), the PFC power stage module (50) and the PFC voltage detection module (60); The PFC output module (70) is connected to the PFC power stage module (50) and the PFC voltage detection module (60) respectively; The compensation boost control module (30) can control the PFC power control module (40) to increase the PFC output voltage when the input voltage detection module (20) detects that the input voltage has increased to a preset value.

2. A power supply circuit capable of improving PF and THD values ​​of a PFC circuit according to claim 1, characterized in that: The input voltage detection module (20) comprises a diode D3, resistors R4-6, a capacitor C1, a capacitor C4 and a voltage stabilizing diode ZD1; the anode of the diode D3 is connected to the input rectification and filtering module (10); the cathode of the diode D3 is respectively connected to one end of the capacitor C1 and one end of the resistor R4; the other end of the resistor R4 is respectively connected to one end of the capacitor C4, one end of the resistor R6, one end of the voltage stabilizing diode ZD1 and the first comparison end of the compensation boost control module (30) via the resistor R5; the other end of the capacitor C4, the other end of the resistor R6, the other end of the voltage stabilizing diode ZD1 and the other end of the capacitor C1 are grounded.

3. A power supply circuit capable of improving PF and THD values ​​of a PFC circuit according to claim 1, characterized in that: The compensation boost control module (30) comprises a comparator U2, a transistor Q16, a resistor R12 and a capacitor C6, the non-phase input end of the comparator U2 is connected to the input voltage detection module (20), the inverting input end of the comparator U2 is connected to the reference voltage, the output end of the comparator U2 is connected to the base of the transistor Q16, the power supply end of the comparator U2 is connected to VCC1, the collector of the transistor Q16 is respectively connected to one end of the resistor R12 and one end of the capacitor C6, the other end of the resistor R12 and the other end of the capacitor C6 are connected to the PFC power control module (40), and the emitter of the transistor Q16 is grounded.

4. A power supply circuit capable of improving PF and THD values ​​of a PFC circuit according to claim 1, characterized in that: The PFC power stage module (50) comprises a transformer L1, a MOS tube Q1, a resistor R1 and a resistor R3; one end of the primary winding of the transformer L1 is connected to the input rectifier filter module (10); the other end of the primary winding of the transformer L1 is connected to the drain of the MOS tube Q1; the source of the MOS tube Q1 is grounded via the resistor R3; and the gate of the MOS tube Q1 is connected to the PFC power control module (40) via the resistor R1.

5. The power supply circuit capable of improving PF and THD values ​​of a PFC circuit according to claim 1, characterized in that: The PFC voltage detection module (60) comprises resistors R14-17 and a capacitor C7, one end of the resistor R14 is connected to the PFC output module (70), the other end of the resistor R14 is connected to one end of the capacitor C7, one end of the resistor R17 and the PFC power control module (40) via resistors R15 and R16 respectively, and the other end of the capacitor C7 and one end of the resistor R17 are grounded.

6. The power supply circuit capable of improving PF and THD values ​​of a PFC circuit according to claim 1, characterized in that: The PFC output module (70) comprises a diode D2 and a capacitor CE1, wherein the anode of the diode D2 is connected to the PFC power stage module (50), the cathode of the diode D2 is respectively connected to one end of the capacitor CE1 and the load, and the other end of the capacitor CE1 is grounded.

7. The power supply circuit capable of improving PF and THD values ​​of a PFC circuit according to claim 1, characterized in that: It also includes a lightning protection module (80) connected to the input rectification and filtering module (10).

Images