Anti-harmonic AC-DC conversion circuit based on power factor correction

Abstract

The utility model provides an anti-harmonic AC-DC conversion circuit based on power factor correction, and the circuit comprises an EMI filter circuit which is connected with an AC input; the full-bridge rectifier circuit is electrically connected with the EMI filter circuit; the boost type APFC circuit is electrically connected with the full-bridge rectification circuit; the half-bridge LLC resonance circuit is electrically connected with the boost type APFC circuit; the synchronous rectification circuit is electrically connected with the half-bridge LLC resonance circuit; the multi-voltage output circuit is electrically connected with the synchronous rectification circuit; according to the utility model, the EMI filter circuit, the full-bridge rectification circuit, the boost APFC circuit, the half-bridge LLC resonance circuit, the synchronous rectification circuit, the multi-voltage output circuit and other modules are integrated, so that efficient and stable electric energy conversion is realized, harmonic interference is reduced, and the power factor is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply circuits, in particular to an anti-harmonic AC-DC conversion circuit based on power factor correction. Background Art

[0002] With the popularity of power electronic devices in daily life and industrial applications, the design of AC-DC power converters with high efficiency, high power density and low electromagnetic interference (EMI) has become a key demand. Traditional non-power factor correction (PFC) power supplies will generate significant current harmonics during the conversion process, which not only reduces the efficiency of the power grid, but may also cause interference to other sensitive equipment. Therefore, the design of AC-DC converters with integrated power factor correction function is particularly important to meet strict international energy efficiency standards and electromagnetic compatibility (EMC) requirements.

[0003] There are several key problems in the AC-DC converter in the prior art, especially how to achieve good power factor and low harmonic distortion while ensuring high efficiency. Traditional solutions, such as passive PFC technology, can improve the power factor to a certain extent, but they are large in size, heavy in weight and low in efficiency. In contrast, active PFC technology, especially the design of boost active power factor correction (APFC) circuit, significantly improves the power factor to close to 1 by adjusting the input current in real time to follow the input voltage, effectively reducing the harmonic content of the input current and reducing pollution to the power grid.

[0004] However, even with the adoption of APFC technology, it remains a challenge to maintain high efficiency and flexibility in the subsequent DC-DC conversion stage while ensuring that the circuit can adapt to different output voltage requirements. This is especially true in application scenarios that require multiple voltage outputs. Traditional multi-channel output designs are often complex and costly, and it is difficult to balance size, efficiency, and flexibility.

[0005] Therefore, it is necessary to provide an anti-harmonic AC-DC conversion circuit based on power factor correction to solve the above technical problems. Utility Model Content

[0006] In order to solve the above technical problems, the utility model provides an anti-harmonic AC-DC conversion circuit based on power factor correction, which realizes efficient and stable power conversion by integrating modules such as EMI filter circuit, full-bridge rectifier circuit, boost APFC circuit, half-bridge LLC resonant circuit, synchronous rectifier circuit and multi-voltage output circuit, while reducing harmonic interference and improving power factor.

[0007] The utility model provides an anti-harmonic AC-DC conversion circuit based on power factor correction, comprising:

[0008] EMI filter circuit, connected to AC input;

[0009] A full-bridge rectifier circuit, electrically connected to the EMI filter circuit;

[0010] A boost APFC circuit, electrically connected to the full-bridge rectifier circuit;

[0011] A half-bridge LLC resonant circuit, electrically connected to the boost APFC circuit;

[0012] a synchronous rectification circuit, electrically connected to the half-bridge LLC resonant circuit;

[0013] A multi-voltage output circuit, electrically connected to the synchronous rectification circuit;

[0014] Wherein, the multi-voltage output circuit comprises:

[0015] A voltage stabilizing circuit 1, used for receiving the voltage output by the synchronous rectification circuit and converting it into a first predetermined voltage;

[0016] A second voltage stabilizing circuit, configured to receive the voltage output by the synchronous rectification circuit and convert the voltage into a second predetermined voltage, wherein the second predetermined voltage is different from the first predetermined voltage;

[0017] An SPDT relay, whose common terminal is grounded, has a first set of contacts connected to voltage divider circuit one, and a second set of contacts connected to voltage divider circuit two. The relay selectively closes the first set of contacts or the second set of contacts according to a control signal so as to send the corresponding voltage divider signal to the feedback control system, thereby controlling the output of the first predetermined voltage or the second predetermined voltage.

[0018] Preferably, it also includes an APFC controller electrically connected to the boost APFC circuit.

[0019] Preferably, it also includes an LLC resonant controller electrically connected to the half-bridge LLC resonant circuit.

[0020] Preferably, it also includes a synchronous rectification controller electrically connected to the synchronous rectification circuit.

[0021] Preferably, a microcontroller is further included, which is used to generate a control signal to drive the SPDT relay to selectively output the first predetermined voltage or the second predetermined voltage according to a preset logic.

[0022] Preferably, the voltage stabilizing circuit 1 and the voltage stabilizing circuit 2 are both voltage stabilizers.

[0023] Compared with the related art, the anti-harmonic AC-DC conversion circuit based on power factor correction provided by the utility model has the following beneficial effects:

[0024] This utility model significantly improves the power conversion efficiency and greatly reduces harmonic interference by integrating advanced technologies such as EMI filtering, full-bridge rectification, boost APFC, half-bridge LLC resonance, synchronous rectification and multi-voltage output. This circuit not only achieves high power factor operation and improves energy utilization efficiency, but also ensures the stability and accuracy of the output voltage. At the same time, its multi-voltage output design meets the power requirements of different devices and provides an efficient and reliable power supply solution for modern electronic equipment and power systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A circuit diagram of an anti-harmonic AC-DC conversion circuit based on power factor correction provided by the utility model;

[0026] Figure 2 The utility model provides a multi-circuit output voltage schematic diagram of an anti-harmonic AC-DC conversion circuit based on power factor correction. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] A harmonic-resistant AC-DC conversion circuit based on power factor correction, reference Figure 1 and Figure 2 Shown, including

[0031] EMI filter circuit, connected to AC input.

[0032] In this embodiment, the EMI filter circuit is connected to the AC input to filter out high-frequency noise and electromagnetic interference in the input power grid to ensure the stable operation of subsequent circuits. The EMI filter circuit is a four-terminal passive network composed of concentrated parameter components, mainly including common-mode inductors, differential-mode inductors, common-mode capacitors and differential-mode capacitors, etc. These components can effectively attenuate common-mode and differential-mode interference noise on the AC input line.

[0033] The full-bridge rectifier circuit is electrically connected to the EMI filter circuit.

[0034] In this embodiment, the full-bridge rectifier circuit is electrically connected to the EMI filter circuit to convert the filtered AC power into DC power, thereby providing a stable DC power supply for subsequent circuits.

[0035] The boost APFC circuit is electrically connected to the full-bridge rectifier circuit, and the boost APFC circuit is electrically connected to an APFC controller.

[0036] In this embodiment, it is electrically connected to the full-bridge rectifier circuit to improve the power factor of the circuit. The APFC circuit controls the waveform of the input current to keep it in phase with the input voltage waveform, thereby effectively reducing reactive power and improving the efficiency of power utilization.

[0037] The half-bridge LLC resonant circuit is electrically connected to the boost APFC circuit, and the half-bridge LLC resonant circuit is electrically connected to an LLC resonant controller.

[0038] In this embodiment, it is electrically connected to the boost APFC circuit as the main conversion part of the circuit, responsible for converting DC power into high-frequency AC power so that it can be rectified by the subsequent synchronous rectification circuit. The LLC resonant circuit has the characteristics of high efficiency and low loss, which can further improve the power conversion efficiency of the circuit.

[0039] The synchronous rectification circuit is electrically connected to the half-bridge LLC resonant circuit, and the synchronous rectification circuit is electrically connected to a synchronous rectification controller.

[0040] In this embodiment, it is electrically connected to the half-bridge LLC resonant circuit to convert high-frequency AC power into DC power. The synchronous rectifier circuit achieves synchronization with the output frequency of the LLC resonant circuit by controlling the switching state of the rectifier tube, thereby reducing energy loss during the rectification process.

[0041] The multi-voltage output circuit is electrically connected to the synchronous rectification circuit.

[0042] In this embodiment, it is electrically connected to the synchronous rectification circuit to convert the rectified direct current into multiple predetermined voltages to meet the power requirements of different electronic devices. The multi-voltage output circuit includes modules such as a voltage stabilizing circuit, a voltage dividing circuit, and an SPDT relay. The voltage stabilizing circuit is responsible for receiving the voltage output by the synchronous rectification circuit and converting it into a predetermined stable voltage; the voltage dividing circuit is used to generate a feedback signal proportional to the predetermined voltage; the SPDT relay selectively closes the corresponding contacts according to the control signal, and sends the corresponding voltage dividing signal to the feedback control system, thereby controlling the output of the corresponding predetermined voltage.

[0043] Specifically, the multi-voltage output circuit includes:

[0044] A voltage stabilizing circuit 1, used for receiving the voltage output by the synchronous rectification circuit and converting it into a first predetermined voltage;

[0045] A second voltage stabilizing circuit, configured to receive the voltage output by the synchronous rectification circuit and convert the voltage into a second predetermined voltage, wherein the second predetermined voltage is different from the first predetermined voltage;

[0046] An SPDT relay, whose common terminal is grounded, has a first set of contacts connected to voltage divider circuit one, and a second set of contacts connected to voltage divider circuit two. The relay selectively closes the first set of contacts or the second set of contacts according to a control signal so as to send the corresponding voltage divider signal to the feedback control system, thereby controlling the output of the first predetermined voltage or the second predetermined voltage.

[0047] It also includes a microcontroller for generating a control signal to drive the SPDT relay to selectively output a first predetermined voltage or a second predetermined voltage according to a preset logic.

[0048] Exemplarily, in a multi-voltage output circuit, the electrical input voltage is 15V, and is initially filtered by an input filter circuit composed of C1 and C2 to reduce input ripple.

[0049] The first voltage regulator circuit is the LM7805 voltage regulator, which is a three-terminal voltage regulator with a fixed output voltage of 5V. Its input voltage comes from the input filter circuit, and the output voltage is filtered by the output filter circuit composed of C6 and C7, ultimately providing a stable output voltage of 5V.

[0050] The first voltage regulator circuit is the LM7812 voltage regulator, which is a three-terminal voltage regulator with a fixed output voltage of 12V. Its input voltage comes from the input filter circuit, and the output voltage is filtered by the output filter circuit composed of C9 and C10, ultimately providing a stable 12V output voltage.

[0051] SPDT relay K1 is a double-throw relay with two contacts. When the coil of K1 receives a GPIO signal, the relay switches the contacts according to the preset logic.

[0052] The GPIO signal is provided by the microcontroller and is used to control the action of relay K1. When the GPIO signal is at a high level, the coil of K1 receives the signal, the relay switches the contacts, and the output voltage switches to 12V; when the GPIO signal is at a low level, the coil of K1 does not receive the signal, the relay maintains the contact state unchanged, and the output voltage remains at 5V.

[0053] In addition, R1 acts as a bias resistor to provide a stable bias voltage for the base of the transistor Q1 connected to it, ensuring that the transistor operates at a preset bias point; Q1 acts as an amplifier element, which provides gain and amplifies current or voltage signals under the action of the input signal; D1 is connected to the collector or emitter of the transistor, and it may act as a clamping diode to prevent reverse voltage from damaging the transistor.

[0054] The working principle of the anti-harmonic AC-DC conversion circuit based on power factor correction provided by the utility model is as follows: by integrating EMI filtering, full-bridge rectification, boost APFC, half-bridge LLC resonance, synchronous rectification and multi-voltage output and other advanced technologies, the power conversion efficiency is significantly improved and the harmonic interference is greatly reduced. The circuit not only realizes high power factor operation and improves energy utilization efficiency, but also ensures the stability and accuracy of the output voltage. At the same time, its multi-voltage output design meets the power requirements of different devices and provides an efficient and reliable power supply solution for modern electronic equipment and power systems.

[0055] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An anti-harmonic AC-DC conversion circuit based on power factor correction, characterized in that: include EMI filter circuit, connected to AC input; A full-bridge rectifier circuit, electrically connected to the EMI filter circuit; A boost APFC circuit, electrically connected to the full-bridge rectifier circuit; A half-bridge LLC resonant circuit electrically connected to the boost APFC circuit; a synchronous rectification circuit, electrically connected to the half-bridge LLC resonant circuit; a multi-voltage output circuit, electrically connected to the synchronous rectification circuit; Wherein, the multi-voltage output circuit comprises: A voltage stabilizing circuit 1, used for receiving the voltage output by the synchronous rectification circuit and converting it into a first predetermined voltage; A second voltage stabilizing circuit, configured to receive the voltage output by the synchronous rectification circuit and convert the voltage into a second predetermined voltage, wherein the second predetermined voltage is different from the first predetermined voltage; An SPDT relay, whose common terminal is grounded, has a first set of contacts connected to voltage divider circuit one, and a second set of contacts connected to voltage divider circuit two. The relay selectively closes the first set of contacts or the second set of contacts according to a control signal so as to send the corresponding voltage divider signal to the feedback control system, thereby controlling the output of the first predetermined voltage or the second predetermined voltage.

2. The anti-harmonic AC-DC conversion circuit based on power factor correction according to claim 1, characterized in that: An APFC controller is also included, which is electrically connected to the boost APFC circuit.

3. The anti-harmonic AC-DC conversion circuit based on power factor correction according to claim 2, characterized in that: It also includes an LLC resonant controller electrically connected to the half-bridge LLC resonant circuit.

4. The anti-harmonic AC-DC conversion circuit based on power factor correction according to claim 3 is characterized in that: It also includes a synchronous rectification controller electrically connected to the synchronous rectification circuit.

5. The anti-harmonic AC-DC conversion circuit based on power factor correction according to claim 4, characterized in that: It also includes a microcontroller for generating a control signal to drive the SPDT relay to selectively output a first predetermined voltage or a second predetermined voltage according to a preset logic.

6. The anti-harmonic AC-DC conversion circuit based on power factor correction according to claim 5, characterized in that: The voltage stabilizing circuit 1 and the voltage stabilizing circuit 2 are both voltage stabilizers.

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