An AC / DC power supply output ripple suppression method and system based on adaptive PR parameter adjustment

Abstract

The application discloses an AC / DC power supply output ripple suppression method and system based on adaptive PR parameter adjustment, and relates to the technical field of power electronic power supplies. The method comprises the following steps: obtaining the difference between the acquired LLC output voltage of the latter stage and a reference voltage; performing ripple frequency detection on the obtained difference value to obtain the ripple frequency of the LLC output voltage of the latter stage; and dynamically adjusting the zero-pole configuration of a PR controller according to the ripple frequency of the LLC output voltage of the latter stage. When the resonance frequency of the PR controller is equal to the ripple frequency of the LLC output voltage of the latter stage, the result output by the PR controller is superimposed with the result output by a PI controller, and the superimposed result is transmitted to the LLC of the latter stage as a switching frequency. The application can significantly improve the output voltage quality of the LLC of the latter stage, improve the stability of the AC / DC power supply system, and has high engineering application value.

Description

Technical Field

[0001] This invention relates to the field of power electronic power supply technology, and in particular to an AC / DC power supply output ripple suppression method and system based on adaptive PR parameter adjustment. Background Technology

[0002] In AC / DC converters, output voltage ripple suppression is one of the key factors affecting power quality and system stability. Traditional AC / DC power supplies typically employ an architecture combining a pre-stage PFC (Power Factor Correction) stage with a post-stage LLC (Logical Link Control) stage to improve the power factor and achieve efficient energy conversion. However, in applications with a wide input frequency range (e.g., 47Hz to 63Hz, 400Hz to 800Hz), the double-frequency ripple from the pre-stage PFC output is directly transmitted to the input of the post-stage LLC, further affecting the final output voltage and resulting in a large output voltage Vout ripple amplitude.

[0003] Currently, a common method to suppress output voltage ripple in the subsequent LLC stage is to increase the output filter capacitor capacitance by adding a large-capacity electrolytic capacitor at the output terminal of the subsequent LLC stage to reduce output voltage ripple. However, this method has the following problems:

[0004] Increased size and cost: Large-capacity electrolytic capacitors significantly increase the size and cost of the system, making them unsuitable for high power density applications.

[0005] Low-temperature performance degradation: In low-temperature environments, the equivalent series resistance (ESR) of electrolytic capacitors increases significantly, leading to aggravated output ripple in the pre-stage PFC and thus reducing ripple suppression effect. Summary of the Invention

[0006] The purpose of this invention is to provide an AC / DC power supply output ripple suppression method and system based on adaptive PR parameter adjustment, to solve the technical problems of increased size and cost, and decreased low-temperature performance caused by existing techniques for suppressing output voltage ripple in the downstream LLC stage. The various technical effects of the preferred solutions among the many technical solutions provided by this invention are detailed below.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides an AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment, used to detect and eliminate the frequency of double the power frequency ripple when the pre-stage PFC and post-stage LLC lack communication capability. The method includes a PR controller and a PI controller, and its steps include:

[0009] The difference between the obtained output voltage of the subsequent LLC stage and the reference voltage is calculated.

[0010] The obtained difference is subjected to ripple frequency detection to obtain the ripple frequency of the output voltage of the subsequent LLC.

[0011] Based on the ripple frequency of the output voltage of the subsequent LLC, the zero-pole configuration of the PR controller is dynamically adjusted. When the resonant frequency of the PR controller is equal to the ripple frequency of the output voltage of the subsequent LLC, the difference obtained is superimposed on the result output by the PR controller and the result output by the PI controller. The superimposed result is transmitted to the subsequent LLC as the switching frequency.

[0012] In one or more embodiments, ripple frequency detection is performed on the obtained difference, including the following steps:

[0013] S201. Configure and initialize the first available output frequency and the second available output frequency;

[0014] S202. Subtract the obtained difference from the first available output frequency, and multiply the difference by the gain coefficient K to obtain the first product;

[0015] S203. Integrate the first available output frequency and multiply it with the second available output frequency to obtain the second product;

[0016] S204. Take the difference between the first product and the second product, multiply the difference by the second available output frequency, and integrate the result to update the first available output frequency.

[0017] S205. The difference obtained is subtracted from the first available output frequency, and the difference is multiplied by the second product. After multiplying, the product is multiplied by the proportional coefficient -r, and the integral of the product is used to update the second available output frequency.

[0018] S206. Return to step S202 until the second available output frequency is within the set range, then the ripple detection ends. The second available output frequency is the ripple frequency of the output voltage of the subsequent LLC.

[0019] In one or more embodiments, dynamically adjusting the zero-pole configuration of the PR controller based on the ripple frequency of the output voltage of the subsequent LLC includes:

[0020] After discretizing the transfer function of the PR controller, the parameters of the PR controller are calculated based on the ripple frequency of the output voltage of the subsequent LLC.

[0021] In one or more embodiments, the expression obtained by discretizing the transfer function of the PR controller is:

[0022] ;

[0023] in, The calculation cycle of the discrete controller. For proportional gain, For resonant gain, The resonant frequency, is the damping factor, and z is the transform domain variable in discrete-time system analysis.

[0024] In one or more embodiments, before superimposing the obtained difference value through the output of the PR controller with the output of the PI controller, the obtained difference value is adjusted by the PI controller to obtain a reference value for the switching frequency corresponding to the output voltage of the subsequent LLC.

[0025] In one or more embodiments, before transmitting the superimposed result to the subsequent LLC, the superimposed result is converted from a discrete digital signal into a continuous analog signal by enhanced pulse width modulation.

[0026] In one or more embodiments, the obtained output voltage of the subsequent LLC is converted from analog to digital and then the difference is calculated with the reference voltage.

[0027] In one or more embodiments, after the downstream LLC boost soft-start is completed, the output voltage of the downstream LLC is obtained through a voltage divider resistor.

[0028] According to another aspect of the present invention, an AC / DC power supply output ripple suppression system based on adaptive PR parameter adjustment is also provided for performing the AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment described above, including a frequency detection module, a PR controller, a PI controller, a digital-to-analog converter, a sampling module, an analog-to-digital converter, a subtractor, and an adder.

[0029] The sampling module is connected to the output terminal of the subsequent LLC and is used to collect the output voltage of the subsequent LLC;

[0030] The analog-to-digital converter is connected to the sampling module and is used to convert the output voltage of the subsequent LLC from a continuous analog signal into a discrete digital signal.

[0031] The subtractor is connected to the analog-to-digital converter and is used to calculate the difference between the output voltage of the subsequent LLC stage after conversion by the analog-to-digital converter and the reference voltage.

[0032] The frequency detection module is connected to the subtractor and is used to detect the ripple frequency of the subtractor's output to obtain the ripple frequency of the output voltage of the subsequent LLC.

[0033] The PR controller is connected to the frequency detection module and dynamically adjusts its zero-pole configuration according to the ripple frequency of the output voltage of the subsequent LLC. When the resonant frequency of the PR controller is equal to the ripple frequency of the output voltage of the subsequent LLC, it outputs a resonant frequency that eliminates twice the power frequency ripple.

[0034] The PI controller is connected to the subtractor and is used to adjust the output of the subtractor to obtain a reference value of the switching frequency corresponding to the output voltage of the subsequent LLC.

[0035] The digital-to-analog converter is connected to the PI controller and the PR controller through the adder. The adder superimposes the outputs of the PR controller and the PI controller. The digital-to-analog converter converts the superimposed ripple frequency, which eliminates double the power frequency ripple, from a discrete digital signal into a continuous analog signal and transmits it to the subsequent LLC stage.

[0036] In one or more embodiments, the frequency detection module is an SOGI-FLL frequency detection loop, and the SOGI-FLL frequency detection loop has multiple preset output frequencies.

[0037] Implementing one of the above-described technical solutions of the present invention has the following advantages or beneficial effects:

[0038] The invention obtains the output voltage ripple of the subsequent LLC through ADC (Analog-to-Digital Converter), obtains the ripple frequency of the subsequent stage through frequency detection, and adaptively designs the resonant frequency of the PR controller based on the obtained ripple frequency of the subsequent stage, thereby reducing the gain at the output voltage ripple frequency and achieving the effect of reducing the amplitude of the output voltage ripple.

[0039] This invention achieves digital control and can reduce the output frequency ripple by twice without increasing the output capacitor capacity. Especially under low temperature conditions, when the ESR of the front-stage PFC electrolytic capacitor increases and the output ripple of the front-stage PFC increases significantly, this method can significantly reduce the output voltage ripple of the subsequent LLC. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0041] Figure 1 This is a flowchart of an AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to an embodiment of the present invention;

[0042] Figure 2 This is a flowchart of a ripple frequency detection method according to an embodiment of the present invention;

[0043] Figure 3 This is a block diagram illustrating the principle of ripple frequency detection according to an embodiment of the present invention;

[0044] Figure 4 This is a structural diagram of an AC / DC power supply output ripple suppression system based on adaptive PR parameter adjustment according to an embodiment of the present invention;

[0045] Figure 5 This is a schematic diagram of the output voltage of the front-end PFC and the rear-end LLC obtained using a conventional PI controller according to an embodiment of the present invention.

[0046] Figure 6 This is a schematic diagram of the output voltage of the front-end PFC and the rear-end LLC obtained by using an AC / DC power supply output ripple suppression system based on adaptive PR parameter adjustment according to an embodiment of the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the present invention clearer, various exemplary embodiments described below will be referenced to the accompanying drawings, which form part of the exemplary embodiments, illustrating various exemplary embodiments that may be used to implement the present invention. Unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. It should be understood that they are merely examples of processes, methods, and apparatuses consistent with some aspects of the present invention disclosed as detailed in the appended claims, and other embodiments may be used, or structural and functional modifications may be made to the embodiments listed herein without departing from the scope and spirit of the present invention.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," etc., indicate the orientation or positional relationship based on the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the referred element must have a specific orientation, or be constructed and operated in a specific orientation. The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. The term "multiple" means two or more. The terms "connected" and "linked" should be interpreted broadly, for example, they can be fixed connections, detachable connections, integral connections, mechanical connections, electrical connections, communication connections, direct connections, indirect connections through an intermediate medium, and can be the internal connection of two elements or the interaction relationship between two elements. The term "and / or" includes any and all combinations of one or more of the related listed items. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] To illustrate the technical solution described in this invention, specific embodiments are described below, showing only the parts related to the embodiments of this invention.

[0050] Example 1:

[0051] like Figures 1-3 As shown, this embodiment provides an AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment. This method detects and eliminates the frequency of double the power frequency ripple when the pre-stage PFC and post-stage LLC lack communication capabilities. It includes a parallel PR controller and a PI controller. The steps of this method include:

[0052] S100. The difference between the obtained output voltage Vout of the subsequent LLC and the reference voltage Vref is calculated to obtain the difference value err.

[0053] In one or more embodiments, after the downstream LLC boost soft-start is completed, the output voltage of the downstream LLC is obtained through a voltage divider resistor.

[0054] Furthermore, the obtained output voltage of the subsequent LLC is converted from analog to digital and then the difference is calculated with the reference voltage.

[0055] S200. Perform ripple frequency detection on the obtained difference err to obtain the ripple frequency of the output voltage of the subsequent LLC stage.

[0056] In one or more embodiments, ripple frequency detection is performed on the obtained difference, including the following steps:

[0057] S201. Configure and initialize the first available output frequency and the second available output frequency.

[0058] S202. Subtract the obtained difference from the first available output frequency, and multiply the difference by the gain coefficient K to obtain the first product.

[0059] S203. Integrate the first available output frequency and multiply it with the second available output frequency to obtain the second product.

[0060] S204. Take the difference between the first product and the second product, multiply the difference by the second available output frequency, integrate the result, and update the first available output frequency.

[0061] S205. Subtract the obtained difference from the first available output frequency, multiply the difference by the second product, multiply the product by the proportional coefficient -r, and integrate the product. Update the second available output frequency with the integral result.

[0062] S206. Return to step S202 until the second available output frequency is within the set range. The ripple detection ends then. The second available output frequency is the ripple frequency of the output voltage of the subsequent LLC stage. .

[0063] In a specific implementation, the reference value for K can be 1.414. The integral can be a Fourier transform or a wavelet transform, which will not be elaborated here. It should be noted that the upper limit of the integral can be twice the size of the ripple, and the lower limit of the integral can be 0. The size of r affects the convergence speed; the larger the value, the faster the convergence, but it will introduce overshoot and oscillation amplitude in the output result. In this embodiment, the reference value for r is 46.

[0064] It should also be noted that the number of second available output frequencies can be preset to multiple, and the multiple possible output frequencies speed up the process of obtaining the second available output frequency, thereby improving the efficiency of this method.

[0065] S300: Based on the ripple frequency of the output voltage of the subsequent LLC stage, dynamically adjust the zero-pole configuration of the PR controller. When the resonant frequency of the PR controller... When the ripple frequency of the output voltage of the subsequent LLC is equal to that of the PR controller, the result of the difference err is superimposed with the result of the PI controller, and the superimposed result is transmitted to the subsequent LLC as the switching frequency.

[0066] Understandably, as the detected ripple frequency changes, the zeros and poles of the PR controller also change. Therefore, the aforementioned dynamic adjustment of the PR controller's zero and pole configuration includes:

[0067] After discretizing the transfer function of the PR controller, the parameters of the PR controller are calculated based on the ripple frequency of the output voltage of the subsequent LLC.

[0068] The PR controller transfer function is:

[0069] (1);

[0070] in For proportional gain, in this embodiment, the PR controller and PI controller are used in parallel, taking... It is 0. For resonant gain, It is the resonant frequency. It is the damping factor, used to control the width of the resonance and avoid excessive oscillation. s is the ripple frequency of the output voltage of the subsequent LLC stage.

[0071] In order for the PR controller to function correctly with different frequency inputs, it is necessary to obtain The discretized expression. Furthermore, the expression obtained by discretizing the transfer function of the PR controller is:

[0072] (2);

[0073] in, The calculation cycle of the discrete controller. For proportional gain, For resonant gain, Let z be the resonant frequency. In discrete-time system analysis, z is a transform domain variable used to map the discretized system from the time domain to the z-domain. z corresponds to the Laplace transform variable "s" in continuous-time systems. Through this transformation, the difference equations in the discrete-time domain can be converted into algebraic equations in the z-domain, facilitating the analysis of the system's stability, frequency response, and other characteristics.

[0074] Understandably, the resonant frequency of the PR controller is always equal to the detected output voltage Vout ripple frequency, which can minimize the gain at the output voltage Vout ripple frequency.

[0075] In this step, before superimposing the result of the PR controller output and the result of the PI controller output, the PI controller is used to adjust the obtained difference to obtain a reference value for the switching frequency corresponding to the output voltage of the subsequent LLC.

[0076] Furthermore, before transmitting the superimposed result to the subsequent LLC, the discrete digital signal is converted into a drive signal using enhanced pulse width modulation (EPWM). This can be achieved using an EPWM module.

[0077] The method in this embodiment is based on a frequency detection and PR controller combination for suppressing output voltage Vout ripple. By detecting the ripple frequency of the output voltage Vout of the subsequent LLC, the resonant frequency of the PR controller is adaptively adjusted to reduce the gain at that frequency, thereby effectively suppressing twice the power frequency ripple. This method has the following advantages:

[0078] No need to add large-capacity output electrolytic capacitors, making it suitable for high power density applications;

[0079] By using digital control technology, it can adapt to power frequency ripple changes over a wide input frequency range and improve the output voltage Vout ripple suppression capability.

[0080] It can effectively suppress output voltage Vout ripple even in low-temperature environments, thus improving system reliability.

[0081] Therefore, this method can significantly improve the output voltage Vout quality of the subsequent LLC, enhance the stability of the AC / DC power supply system, and has high engineering application value.

[0082] Example 2:

[0083] like Figure 4 As shown, this embodiment provides an AC / DC power supply output ripple suppression system based on adaptive PR parameter adjustment, used to execute the AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment described in Embodiment 1. It includes a frequency detection module, a PR controller, a PI controller, a digital-to-analog converter, a sampling module, an analog-to-digital converter, a subtractor, and an adder.

[0084] The sampling module is connected to the output terminal of the subsequent LLC and is used to collect the output voltage of the subsequent LLC.

[0085] The analog-to-digital converter is connected to the sampling module to convert the output voltage of the subsequent LLC from a continuous analog signal into a discrete digital signal.

[0086] The subtractor is connected to the analog-to-digital converter (ADC) and is used to calculate the difference between the output voltage of the LLC stage after the ADC conversion and the reference voltage.

[0087] The frequency detection module is connected to the subtractor and is used to detect the ripple frequency of the subtractor's output to obtain the ripple frequency of the output voltage of the subsequent LLC stage. The specific detection method is the same as in Embodiment 1, please refer to Embodiment 1 for details.

[0088] The PR controller is connected to the frequency detection module. Based on the ripple frequency of the output voltage of the subsequent LLC, it dynamically adjusts its zero-pole configuration. When the resonant frequency of the PR controller is equal to the ripple frequency of the output voltage of the subsequent LLC, it outputs a resonant frequency that eliminates twice the power frequency ripple.

[0089] The PI controller is connected to the subtractor and is used to adjust the output of the subtractor to obtain a reference value for the switching frequency corresponding to the output voltage of the subsequent LLC stage.

[0090] The digital-to-analog converter is connected to the PI controller and PR controller via an adder. The adder superimposes the outputs of the PR controller and PI controller. The digital-to-analog converter converts the superimposed ripple frequency, which eliminates double the power frequency ripple, from a discrete digital signal into a continuous analog signal and transmits it to the subsequent LLC stage.

[0091] It is understood that the frequency detection module can be an SOGI-FLL frequency detection loop. When it is an SOGI-FLL frequency detection loop, multiple available output frequencies are preset within the SOGI-FLL frequency detection loop (see the first and second available output frequencies in Embodiment 1). This can speed up the process of obtaining the output voltage frequency.

[0092] like Figures 5-6 The image shows two experimental graphs, in which... Figure 5 The experimental graph is obtained using a traditional PI controller. Figure 6 In the solution described in this patent, line one in the figure represents the ripple of the output voltage Vout of the pre-stage PFC, and line two represents the ripple of the output voltage Vout of the post-stage LLC.

[0093] At 100Hz input Figure 5 The output voltage Vout of the LLC stage shown has a ripple of 200mV. Figure 6 The output voltage Vout ripple of the LLC stage shown is 140mV, and it can be clearly seen that the double power frequency ripple of the output voltage Vout ripple is well eliminated and suppressed.

[0094] The above description is merely a preferred embodiment of the present invention. Those skilled in the art will understand that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A method for AC / DC power supply output ripple rejection based on adaptive PR parameter adjustment, characterized by, The application relates to a method for detecting and eliminating double-frequency ripple in the case that a pre-stage PFC and a post-stage LLC do not have communication capability, which comprises a PR controller and a PI controller, and the steps include: differencing the obtained post-stage LLC output voltage from a reference voltage; detecting the ripple frequency of the obtained difference value to obtain the ripple frequency of the post-stage LLC output voltage; dynamically adjusting the zero-pole configuration of the PR controller according to the ripple frequency of the post-stage LLC output voltage; when the resonance frequency of the PR controller is equal to the ripple frequency of the post-stage LLC output voltage, superimposing the result output by the PR controller on the result output by the PI controller, and transmitting the superimposed result to the post-stage LLC as a switching frequency.

2. The AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to claim 1, characterized in that, The ripple frequency detection of the obtained difference value comprises the following steps: S201, configuring and initializing a first available output frequency and a second available output frequency; S202, differencing the obtained difference value from the first available output frequency, multiplying the difference by a gain coefficient K to obtain a first product; S203, multiplying the first available output frequency after integration by the second available output frequency to obtain a second product; S204, differencing the first product from the second product, multiplying the difference by the second available output frequency, and integrating the result to update the first available output frequency; S205, differencing the obtained difference value from the first available output frequency, multiplying the difference by the second product, multiplying the result by a proportional coefficient -r, integrating the obtained product, and updating the second available output frequency with the integration result; S206, returning to step S202 until the second available output frequency is within a set range, and ending the ripple detection, wherein the second available output frequency is the ripple frequency of the post-stage LLC output voltage.

3. The AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to claim 1, characterized in that, The dynamic adjustment of the zero-pole configuration of the PR controller according to the ripple frequency of the post-stage LLC output voltage comprises: discretizing the transfer function of the PR controller, and calculating the parameters of the PR controller according to the ripple frequency of the post-stage LLC output voltage.

4. The AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to claim 3, characterized in that, The expression obtained by discretizing the transfer function of the PR controller is: ； wherein, is the computation period of the discrete controller, is the proportional gain, is the resonant gain, is the resonant frequency, is the damping factor, z is the transform domain variable in the analysis of discrete time systems.

5. The AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to claim 1, characterized in that, Before superimposing the result output by the PR controller on the result output by the PI controller, the PI controller is used to adjust the obtained difference value to obtain a reference value of the switching frequency corresponding to the post-stage LLC output voltage.

6. The AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to claim 1, characterized in that, Before transmitting the superimposed result to the post-stage LLC, the superimposed result is converted into a continuous analog signal through enhanced pulse width modulation.

7. The AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to claim 1, characterized in that, The obtained post-stage LLC output voltage is converted into a digital signal through analog-digital conversion, and then is differenced from a reference voltage.

8. The AC / DC power supply output ripple suppression method based on adaptive PR parameter adjustment according to claim 1, characterized in that, After the soft start of the post-stage LLC is completed, the output voltage of the post-stage LLC is obtained through a voltage dividing resistor.

9. An AC / DC power supply output ripple rejection system based on adaptive PR parameter adjustment, characterized by, The application discloses an AC / DC power output ripple suppression method based on adaptive PR parameter adjustment, which comprises a frequency detection module, a PR controller, a PI controller, a digital-analog converter, a sampling module, an analog-digital converter, a subtractor and an adder. The sampling module is connected with an output end of the post-stage LLC and is used for collecting an output voltage of the post-stage LLC. The analog-digital converter is connected with the sampling module and is used for converting the output voltage of the post-stage LLC from a continuous analog signal into a discrete digital signal. The subtractor is connected with the analog-digital converter and is used for subtracting the output voltage of the post-stage LLC converted by the analog-digital converter from a reference voltage. The frequency detection module is connected with the subtractor and is used for performing ripple frequency detection on an output of the subtractor to obtain a ripple frequency of the output voltage of the post-stage LLC. The PR controller is connected with the frequency detection module and is used for dynamically adjusting zero-pole configurations of the post-stage LLC according to the ripple frequency of the output voltage of the post-stage LLC, and when a resonance frequency of the PR controller is equal to the ripple frequency of the output voltage of the post-stage LLC, a resonance frequency eliminating a double working frequency ripple is output. The PI controller is connected with the subtractor and is used for adjusting the output of the subtractor to obtain a reference value of a switching frequency corresponding to the output voltage of the post-stage LLC. The digital-analog converter is connected with the PI controller and the PR controller through the adder, the adder superimposes outputs of the PR controller and the PI controller, the digital-analog converter converts the superimposed ripple frequency eliminating the double working frequency ripple from the discrete digital signal into the continuous analog signal, and the continuous analog signal is transmitted to the post-stage LLC.

10. The AC / DC power supply output ripple suppression system based on adaptive PR parameter adjustment of claim 9, wherein, The frequency detection module is a SOGI-FLL frequency detection loop, and a plurality of output frequencies are preset in the SOGI-FLL frequency detection loop.

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