Power management system, control module for LLC converter and control method

Abstract

A power management system, a control module for an LLC converter, and a control method are disclosed. One aspect of this disclosure is a control module for an LLC converter having a PFC circuit and an LLC circuit. A bulk capacitor is located between the PFC circuit and the LLC circuit. The control module includes a secondary-side controller coupled to the output of the LLC circuit for receiving the output current of the LLC circuit. The control module also includes an optocoupler circuit coupled to the secondary-side controller. The control module also includes a primary-side controller coupled to both the optocoupler circuit and the PFC circuit. The secondary-side controller generates a PWM signal based on fluctuations in the output current and outputs it to the optocoupler circuit. The optocoupler circuit converts the PWM signal into an analog signal and sends it to the primary-side controller. The primary-side controller adjusts the input current of the PFC circuit based on the analog signal to maintain a stable capacitor voltage across the bulk capacitor.

Description

Technical Field

[0001] This invention relates to a power management system and a control technique for LLC converters, particularly a control technique for controlling relevant electrical parameters between the primary and secondary sides via an optocoupler. Background Technology

[0002] In modern high-power-density and high-power-output power supply units (PSUs), when the output load undergoes large changes—for example, when the output load increases significantly due to electronic data peak processing (EDPP) settings (e.g., from 20% to 170%)—the front-end power accelerator (PFC) circuit reacts slowly to load changes. This causes the voltage of the large-capacity capacitors within the PFC circuit to continuously decrease, gradually increasing the resonant current on the primary side of the LLC circuit until it triggers cycle-by-cycle protection (CBC) or lowers the PFC output voltage, ultimately triggering under-voltage protection (UVP) and shutting down the system. Therefore, there is a need for a technology that can maintain a balance between the input and output power of the PFC circuit and stabilize the voltage of the large-capacity capacitors based on output current fluctuations. Summary of the Invention

[0003] The technology provided by this invention transmits the output current fluctuation information obtained by the secondary controller to the primary controller through an optocoupler circuit. When the primary controller receives the relevant information, it adjusts the input current of the PFC circuit to compensate the large-capacity capacitor in real time to stabilize its capacitor voltage.

[0004] According to a first aspect of the invention, a control module is provided for an LLC converter having a power factor correction (PFC) circuit and an inductor-inductor-capacitor (LLC) circuit. A bulk capacitor is provided between the PFC circuit and the LLC circuit. The control module includes a secondary-side controller coupled to the output of the LLC circuit for receiving the output current of the LLC circuit. The control module also includes an optocoupler coupled to the secondary-side controller. The control module also includes a primary-side controller coupled to the optocoupler circuit and the PFC circuit. The secondary-side controller generates a PWM signal based on fluctuations in the output current and outputs it to the optocoupler circuit. The optocoupler circuit converts the PWM signal into an analog signal and sends it to the primary-side controller. The primary-side controller adjusts the input current of the PFC circuit based on the analog signal to maintain the stability of the capacitor voltage of the bulk capacitor.

[0005] According to a second aspect of the invention, a control method is provided for an LLC converter having a PFC circuit and an LLC circuit. A large-capacity capacitor is located between the PFC circuit and the LLC circuit. The control method includes receiving the output current of the LLC circuit via a secondary-side controller. The control method also includes generating a PWM signal based on fluctuations in the output current via the secondary-side controller and outputting it to an optocoupler circuit. The control method also includes converting the PWM signal into an analog signal via the optocoupler circuit and sending it to a primary-side controller. The control method also includes adjusting the input current of the PFC circuit based on the analog signal via the primary-side controller to maintain a stable capacitor voltage across the large-capacity capacitor.

[0006] According to a third aspect of the present invention, a power management system is provided. The power management system includes an LLC converter. The LLC converter includes a PFC circuit and an LLC circuit. A large-capacity capacitor is located between the PFC circuit and the LLC circuit. The power management system also includes a control module. The control module includes a secondary-side controller coupled to the output of the LLC circuit for receiving the output current of the LLC circuit. The control module also includes an optocoupler circuit coupled to the secondary-side controller. The control module also includes a primary-side controller coupled to the optocoupler circuit and the PFC circuit. The secondary-side controller generates a PWM signal based on fluctuations in the output current and outputs it to the optocoupler circuit. The optocoupler circuit converts the PWM signal into an analog signal and sends it to the primary-side controller. The primary-side controller adjusts the input current of the PFC circuit based on the analog signal to maintain the stability of the capacitor voltage of the large-capacity capacitor.

[0007] The foregoing description is not intended to represent every embodiment or aspect of the invention. Rather, it provides only examples of some novel aspects and features of the invention. The foregoing description will become apparent, as well as other features and advantages of the invention, from the following detailed description of representative embodiments and modes of implementation when taken in conjunction with the accompanying drawings and the claims. Other aspects of the invention will be apparent to those skilled in the art from the detailed description of various embodiments with reference to the drawings and the brief description provided below.

[0008] To provide a better understanding of the above and other aspects of the present invention, specific embodiments are described below in conjunction with the accompanying drawings: Attached Figure Description

[0009] Figure 1 A functional block diagram of a control module for an LLC converter according to various embodiments of the present invention is shown.

[0010] Figure 2 Waveform diagrams illustrating the control module controlling the PFC circuit according to various embodiments of the present invention are shown.

[0011] Figure 3 A flowchart illustrating a control program for an LLC converter according to various embodiments of the present invention is shown.

[0012] In the attached figures, the following labels are used:

[0013] 1000: LLC Converter

[0014] 110: PFC circuit

[0015] 120: LLC circuit

[0016] 130: Large-capacity capacitor

[0017] 140: Load

[0018] 200: Control Module

[0019] 200A: Waveform Diagram

[0020] 210: Secondary side controller

[0021] 220: Primary Side Controller

[0022] 230: Optical coupling circuit

[0023] 231: Optical Coupler

[0024] 232: Filtering Circuit

[0025] S310~S340: Steps Detailed Implementation

[0026] The various embodiments of the present invention will be described in detail below, with illustrations provided. In addition to these detailed descriptions, the present invention can be widely implemented in other embodiments, and any easy substitutions, modifications, or equivalent changes to the described embodiments are included within the scope of the present invention and are subject to the following patent claims. In the description of the specification, many specific details and implementation examples are provided to give the reader a more complete understanding of the present invention; however, these specific details and implementation examples should not be considered as limitations on the present invention. Furthermore, well-known steps or elements are not described in the details to avoid unnecessarily limiting the present invention. In the drawings, the same or similar element symbols are used to represent the same or similar elements.

[0027] Figure 1A functional block diagram of a control module 200 for an LLC converter 1000 according to various embodiments of the present invention is shown. The multi-phase conversion circuit 1000 includes a PFC circuit 110, a large-capacity capacitor 130, and an LLC circuit 120. The large-capacity capacitor 130 is disposed between the PFC circuit 110 and the LLC circuit 120, and the discharge output of the large-capacity capacitor 130 is related to the output power (or voltage) of the PFC circuit. The LLC circuit 120 is coupled to a load 140 and provides output current to the load 140.

[0028] The control module 200 includes a secondary-side controller 210, an optocoupler circuit 230, and a primary-side controller 220. The secondary-side controller 210 is coupled to the output of the LLC circuit 120 and can receive the output current of the LLC circuit 120 and generate a corresponding PWM signal to respond to fluctuations in the output current, such as... Figure 1 As shown. In some embodiments, the secondary-side controller 210 may be part of the LLC circuit 120, or may be implemented by the controller originally used in the LLC circuit 120, such as a digital signal processor (DSP) for controlling the LLC circuit 120. The optocoupler circuit 230 includes an optocoupler 231 and a filter circuit 232, coupled to the secondary-side controller 210 and the primary-side controller 220. The optocoupler 231 can be used to transmit the PWM signal generated by the secondary-side controller 210 to the primary-side controller 220 via the transmitting and receiving ends of the optocoupler 231, while the filter circuit 232 is used to convert the PWM signal received from the receiving end of the optocoupler 231 into an analog signal and provide the analog signal to the primary-side controller 220. The primary-side controller 220 is coupled to the optocoupler circuit 230 and the PFC circuit 110. When the primary-side controller 220 receives an analog signal corresponding to the output current fluctuation, it can adjust the input current of the PFC circuit 110 according to the analog signal, that is, make the input power of the PFC circuit 110 greater than or equal to its output power, i.e., meet the condition (V in *I in )≥(V out *I out ) / η, where V in and I in These are the input voltage and input current of PFC circuit 110, respectively. out and I outHere, η represents the output voltage and output current of LLC circuit 120, respectively, and η is the conversion efficiency. For example, when the primary-side controller 220 receives an analog signal corresponding to a fluctuation (or jump) in the output current, it can quickly adjust the input current of PFC circuit 110 to rapidly increase the input current. In some embodiments, the primary-side controller 220 may be part of PFC circuit 110, or it may be implemented by the controller originally used in PFC circuit 110, such as a digital signal processor (DSP) for controlling PFC circuit 110. Through the above operations, by adjusting the input current of PFC circuit 110, the input / output power is balanced, and the capacitor voltage of large-capacity capacitor 130 can be kept stable.

[0029] Specifically, the secondary-side controller 210, by acquiring the output current of the LLC circuit 120, can determine whether a dynamic load has occurred, i.e., a large fluctuation, such as when the load suddenly increases from 20% to 170% (e.g., the output current increases by 1.4 to 1.8 times). Based on this change in output current, it can generate a PWM signal to the optocoupler circuit 230. The PWM signal is transmitted and converted into an analog signal by the optocoupler circuit 230. The primary-side controller 220 can read this analog signal to obtain the load change (or change value) of the output current. Based on this change value, the primary-side controller 220 can calculate the change in the output power of the LLC circuit, and then calculate the corresponding change in input current. This increases the integral value of the PFC circuit 110 (e.g., through a proportional-integral (PI) controller) to a corresponding value, balancing the input / output power. This prevents the capacitor voltage of large-capacity capacitors from dropping below the lower limit, ensuring that the capacitor voltage fluctuation range is controlled within a certain range, thereby stabilizing the output voltage.

[0030] In some implementations, when the primary-side controller 220 increases the input current of the PFC circuit 110, causing the capacitor voltage of the large-capacity capacitor 130 to increase, if the capacitor voltage exceeds an upper limit, for example, above 435V, the primary-side controller 220 shuts off the input current of the PFC circuit 110 until the capacitor voltage of the large-capacity capacitor 130 drops below a lower limit, for example, below 415V, at which point the input current of the PFC circuit 110 is turned on again. This ensures that the capacitor voltage of the large-capacity capacitor 130 does not exceed the upper voltage withstand limit of the large-capacity capacitor 130.

[0031] Figure 2The diagram illustrates waveforms of the control module controlling the PFC circuit according to various embodiments of the present invention. Through the operations described above, as shown in waveform 200A, by adjusting the input current of the PFC circuit (corresponding to changes in the output current of the LLC circuit), the capacitor voltage of the large-capacity capacitor between the PFC circuit and the LLC circuit can be controlled between 470V and 390V. That is, the fluctuation range of the capacitor voltage is controlled and stabilized within a certain range. Therefore, the overall output voltage of the system can be stabilized, and the CBC protection will not be triggered due to a sudden and significant change in the output current caused by a large change in EDPP.

[0032] Figure 3 A flowchart illustrating a control procedure for an LLC converter according to various embodiments of the present invention is shown. In step S310, the secondary-side controller (e.g., Figure 1 The secondary-side controller 210) receives LLC circuit (e.g. Figure 1 The output current of the LLC circuit 120.

[0033] In step S320, the control method also includes generating a PWM signal based on the fluctuation of the output current by the secondary-side controller and outputting it to the optocoupler circuit (e.g., Figure 1 (Optical coupling circuit 230).

[0034] In step S330, the optocoupler circuit converts the PWM signal into an analog signal and sends it to the primary-side controller (e.g., Figure 1 (Primary side controller 220).

[0035] In step S340, the primary-side controller adjusts the PFC circuit (e.g., based on the analog signal) Figure 1 The input current of the PFC circuit 110 is used to maintain the large capacitance capacitor (e.g., Figure 1 The voltage of the large-capacity capacitor (130) is stabilized. Then, the circuit can return to step S310 to continue receiving the output current from the LLC circuit to maintain the stability of the capacitor voltage.

[0036] In some specific setups, the optocoupler circuit includes an optocoupler and a filter circuit. The optocoupler is used to transmit PWM signals, and the filter circuit is used to convert the PWM signals into analog signals.

[0037] In certain specific configurations, adjusting the input current of the PFC circuit via a primary-side controller includes: calculating the change in the output power of the LLC circuit based on fluctuations in the output current corresponding to the analog signal; and calculating the change in the input current based on the change in output power, and adjusting the input current so that the input power of the PFC circuit is greater than or equal to the output power. The input power is the product of the input voltage and the input current of the PFC circuit.

[0038] In some specific settings, the output power corresponds to a change in the output current, which can be increased from the original output current to 1.4 to 1.8 times.

[0039] In some specific setups, the secondary-side controller generates a PWM signal to the optocoupler circuit based on the output current increasing by 1.4 to 1.8 times.

[0040] In certain settings, the primary-side controller can calculate the change in output power of the LLC circuit based on the increase in output current from 1.4 to 1.8 times, and then calculate the required change in input current of the PFC circuit, so that the PFC circuit increases the input current by the integral value of the proportional-integral controller by the corresponding value.

[0041] In certain specific settings, adjusting the input current of the PFC circuit by the primary-side controller includes: when the primary-side controller increases the input current of the PFC circuit, causing the capacitor voltage of the large-capacity capacitor to increase, if the capacitor voltage exceeds the upper limit, the primary-side controller shuts off the input current of the PFC circuit.

[0042] In certain specific settings, adjusting the input current of the PFC circuit by means of the primary side controller includes: when the primary side controller shuts off the input current of the PFC circuit, causing the capacitor voltage of the large-capacity capacitor to drop, and when the capacitor voltage drops below the lower limit, turning on the input current of the PFC circuit.

[0043] Various embodiments are described with reference to the accompanying drawings, wherein all drawings use the same element reference numerals to denote similar or equivalent elements. The drawings are not necessarily drawn to scale and are provided only to illustrate aspects and features of the invention. Numerous specific details, relationships, and methods are set forth to provide a comprehensive understanding of certain aspects and features of the invention, although those skilled in the art will recognize that these aspects and features can be implemented without one or more of the specific details, relationships, or methods. In some cases, well-known structures or operations are not shown in detail for illustrative purposes. The various embodiments disclosed herein are not necessarily limited to the order of the described actions or events, as some actions may occur in a different order and / or simultaneously with other actions or events. Furthermore, not all actions or events in the drawings are necessary to realize certain aspects and features of the invention.

[0044] Although the invention has been described and illustrated with respect to one or more embodiments, other skilled in the art will recognize or understand equivalent changes and modifications upon reading and understanding this specification and the accompanying drawings. Furthermore, while a particular feature of the invention may be disclosed only in one of several embodiments, this feature may be combined with one or more other features of other embodiments, as these features may be desired and advantageous for any given or particular application.

[0045] While various embodiments of the invention have been described above, it should be understood that they are presented by way of example only and not as limitation. Many changes may be made to the disclosed embodiments based on this disclosure without departing from the spirit or scope of the invention. Therefore, the breadth and scope of the invention should not be limited by any of the above embodiments. Rather, the scope of the invention should be defined according to the appended claims and their equivalents.

Claims

1. A control module for an LLC converter having a power factor correction (PFC) circuit and an LLC circuit, wherein a bulk capacitor is provided between the PFC circuit and the LLC circuit, the control module comprising: A primary and secondary side controller is coupled to an output of the LLC circuit to receive an output current of the LLC circuit. An optical coupling circuit is connected to the secondary-side controller; A primary-side controller is coupled to the optocoupler circuit and the PFC circuit. The secondary-side controller generates a PWM signal based on the fluctuation of the output current and outputs it to the optocoupler circuit. The optocoupler circuit converts the PWM signal into an analog signal and sends it to the primary-side controller. The primary-side controller adjusts an input current of the PFC circuit based on the analog signal to maintain a stable capacitor voltage of the large-capacity capacitor.

2. The control module as described in claim 1, wherein the optical coupling circuit includes an optical coupler and a filter circuit. The optocoupler is used to transmit the PWM signal, and the filter circuit is used to convert the PWM signal into the analog signal.

3. The control module as claimed in claim 1, wherein the primary-side controller adjusts the input current of the PFC circuit according to the analog signal by: Based on the fluctuation of the output current corresponding to the analog signal, the change in the output power of the LLC circuit is calculated; and The change in input current is calculated based on the change in output power, and the input current is adjusted so that the input power of the PFC circuit is greater than or equal to the output power. The input power is the product of the input voltage and the input current of the PFC circuit.

4. The control module as claimed in claim 3, wherein the output power corresponds to the change in the output current, which is an increase from the original output current to 1.4 to 1.8 times.

5. The control module as claimed in claim 4, wherein the secondary-side controller generates the PWM signal to the optocoupler circuit based on the change in the output current from 1.4 times to 1.8 times.

6. The control module as claimed in claim 4, wherein the primary-side controller calculates the change in the output power of the LLC circuit based on the change in the output current from 1.4 times to 1.8 times, and then calculates the required change in the input current of the PFC circuit, so that the PFC circuit increases the input current by a corresponding value through an integral value of a proportional-integral controller.

7. The control module as claimed in claim 4, wherein when the primary-side controller increases the input current of the PFC circuit, causing the capacitor voltage of the large-capacity capacitor to increase, if the capacitor voltage exceeds an upper limit, the primary-side controller shuts off the input current of the PFC circuit until the capacitor voltage drops below a lower limit, at which point the input current of the PFC circuit is turned on.

8. A control method for an LLC converter having a PFC circuit and an LLC circuit, wherein a large capacitance capacitor is provided between the PFC circuit and the LLC circuit, the control method comprising: The output current of the LLC circuit is received by the primary and secondary side controllers; The secondary-side controller generates a PWM signal based on the fluctuation of the output current and outputs it to an optocoupler circuit; The optocoupler circuit converts the PWM signal into an analog signal and sends it to a primary-side controller; and The primary-side controller adjusts an input current of the PFC circuit based on the analog signal to maintain a stable capacitor voltage of the large-capacity capacitor.

9. The control method as described in claim 8, wherein the optical coupling circuit includes an optical coupler and a filter circuit. The optocoupler is used to transmit the PWM signal, and the filter circuit is used to convert the PWM signal into the analog signal.

10. The control method of claim 8, wherein adjusting the input current of the PFC circuit via the primary-side controller comprises: Based on the fluctuation of the output current corresponding to the analog signal, the change in the output power of the LLC circuit is calculated; as well as The change in input current is calculated based on the change in output power, and the input current is adjusted so that the input power of the PFC circuit is greater than or equal to the output power. The input power is the product of the input voltage and the input current of the PFC circuit.

11. The control method of claim 10, wherein the output power corresponds to the change in the output current, which is an increase from the original output current to 1.4 to 1.8 times.

12. The control method of claim 11, wherein the secondary-side controller generates the PWM signal to the optocoupler circuit based on the change in the output current from 1.4 times to 1.8 times.

13. The control method of claim 11, wherein the primary-side controller calculates the change in the output power of the LLC circuit based on the change in the output current from 1.4 times to 1.8 times, and then calculates the required change in the input current of the PFC circuit, so that the PFC circuit increases the input current by a corresponding value through an integral value of a proportional-integral controller.

14. The control method of claim 11, wherein adjusting the input current of the PFC circuit via the primary-side controller comprises: When the primary-side controller increases the input current of the PFC circuit, causing the capacitor voltage of the large-capacity capacitor to increase, if the capacitor voltage exceeds an upper limit, the primary-side controller shuts off the input current of the PFC circuit.

15. The control method of claim 11, wherein adjusting the input current of the PFC circuit via the primary-side controller comprises: When the primary side controller shuts off the input current of the PFC circuit, causing the voltage of the large-capacity capacitor to drop, the input current of the PFC circuit is turned on when the voltage drops below a lower limit.

16. A power management system, comprising: An LLC converter, comprising: A PFC circuit; and An LLC circuit is coupled to the PFC circuit, wherein a large capacitance capacitor is connected between the PFC circuit and the LLC circuit; and One control module includes: A primary and secondary side controller is coupled to an output of the LLC circuit to receive an output current of the LLC circuit. An optical coupling circuit is connected to the secondary-side controller; A primary-side controller is coupled to the optocoupler circuit and the PFC circuit. The secondary-side controller generates a PWM signal based on the fluctuation of the output current and outputs it to the optocoupler circuit. The optocoupler circuit converts the PWM signal into an analog signal and sends it to the primary-side controller. The primary-side controller adjusts an input current of the PFC circuit based on the analog signal to maintain a stable capacitor voltage of the large-capacity capacitor.

17. The power management system of claim 16, wherein the optocoupler circuit includes an optocoupler and a filter circuit. The optocoupler is used to transmit the PWM signal, and the filter circuit is used to convert the PWM signal into the analog signal.

18. The power management system of claim 16, wherein the primary-side controller adjusts the input current of the PFC circuit according to the analog signal by: Based on the fluctuation of the output current corresponding to the analog signal, the change in the output power of the LLC circuit is calculated; and The change in input current is calculated based on the change in output power, and the input current is adjusted so that the input power of the PFC circuit is greater than or equal to the output power. The input power is the product of the input voltage and the input current of the PFC circuit.

19. The power management system of claim 18, wherein the output power corresponds to the change in the output current, which is an increase from the original output current to 1.4 to 1.8 times.

20. The power management system of claim 19, wherein the secondary-side controller generates the PWM signal to the optocoupler circuit based on the change in output current from 1.4 times to 1.8 times.

21. The power management system of claim 19, wherein the primary-side controller calculates the change in output power of the LLC circuit based on the change in output current from 1.4 to 1.8 times, and then calculates the required change in input current of the PFC circuit, so that the PFC circuit increases the input current by a corresponding value through an integral value of a proportional-integral controller.

22. The power management system of claim 19, wherein when the primary-side controller increases the input current of the PFC circuit, causing the capacitor voltage of the large-capacity capacitor to increase, if the capacitor voltage exceeds an upper limit, the primary-side controller shuts off the input current of the PFC circuit until the capacitor voltage drops below a lower limit, at which point the input current of the PFC circuit is turned on.

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