A method and apparatus for dynamically adjusting the output voltage of a power supply device.
By estimating line loss and monitoring PD input voltage, the PSE output voltage is dynamically adjusted, solving the problem that traditional PSE equipment cannot adaptively adjust. This achieves intelligent voltage adaptation, reduces line loss energy consumption, and extends equipment life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGZHOU V-SOLUTION TELECOMM TECH CO LTD
- Filing Date
- 2026-01-22
- Publication Date
- 2026-06-02
AI Technical Summary
Traditional PSE devices cannot adaptively adjust the output voltage according to the dynamic power consumption changes of the PD, which may lead to device restarts or unstable performance. Furthermore, a fixed high voltage may cause heat loss and potential risks.
By estimating line loss and monitoring PD input voltage, the PSE output voltage is adaptively adjusted, including PD level classification, link layer negotiation, fine power negotiation, and voltage information capability identification. The output voltage is dynamically adjusted using an adjustable DC-DC module to ensure that it is compatible with the voltage required by the PD.
It achieves intelligent adaptive adjustment of PSE output voltage, adapts to the dynamic power consumption changes of PD, reduces line loss energy consumption, extends equipment life and improves system reliability.
Smart Images
Figure CN122137695A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of communication technology, and in particular to a method and apparatus for dynamically adjusting the output voltage of a power supply device. Background Technology
[0002] Traditional PSEs (Power Supply Equipment, such as PoE switches) typically determine a fixed output voltage (e.g., 48V or 54V) during the negotiation phase. However, due to the impedance of the transmission cable, long-distance transmission will result in losses, and the actual voltage at the PD (Powered Device) may be lower than the minimum voltage required for its normal operation, causing device restarts or performance instability. At the same time, a fixed high voltage may also cause unnecessary heat loss and potential risks to PDs connected over short distances.
[0003] The invention patent with authorization announcement number CN103399605B discloses an intelligent remote-controlled regulated PoE system. This invention employs a boost converter chip and operational amplifier core processing unit. It uses the boost converter chip's reference voltage for feedback comparison to adjust the output voltage. When the reference voltage pin is lower than the reference voltage, the voltage at the boost converter chip's power output pin increases; conversely, when the reference voltage pin is higher than the reference voltage, the voltage at the boost converter chip's power output pin decreases, thus achieving automatic output voltage adjustment. However, this system lacks PD negotiation and power matching capabilities, as well as line loss estimation. It cannot adjust the voltage based on the dynamic power consumption of the PD, and it lacks a burst current handling mechanism, making it difficult to cope with instantaneous changes in PD power consumption. The adjusted output voltage is therefore insufficiently adaptable. Summary of the Invention
[0004] Therefore, it is necessary to address the technical problem of insufficient output voltage adaptability of PSE in existing technologies by providing a dynamic adjustment method and device for the output voltage of power supply equipment, which can realize intelligent and adaptive adjustment of PSE output voltage. The specific technical solution is as follows: In a first aspect, this application proposes a method for dynamically adjusting the output voltage of a power supply device, comprising the following steps: S1: The PSE detects the PD with a preset safe voltage and classifies the PD to determine the approximate power level of the PD. S2: Establish a data link, negotiate a protocol at the link layer and conduct fine power negotiation with the PD based on the coarse power level to obtain the power negotiation result, and exchange voltage information and capability identifiers at the same time. S3: Based on the power negotiation results, the PSE is powered by a preset standard voltage. Read the PSE's output voltage and output current. S4: Estimate line loss based on the output current and cable impedance or based on the output voltage and voltage feedback at the PD input terminal; S5: Calculate the target output voltage based on the estimated line loss and adjust the PSE output voltage to make the PSE output voltage approach the target output voltage.
[0005] Furthermore, the link layer negotiation protocol in step S2 includes the LLDP protocol. The fine power negotiation includes the powered device transmitting its actual power requirements and voltage tolerance range, and the power supply device feeding back its power supply capability boundaries. The voltage information capability identifier in step S2 is used to determine whether the PD supports voltage information feedback. If the PD supports voltage information feedback, then step S4 estimates the line loss based on the output voltage of the PSE and the voltage at the PD input terminal; otherwise, it estimates the line loss based on the output current at the PSE output terminal and the cable impedance.
[0006] The calculation expression for line loss estimation based on the output voltage of the PSE and the input voltage of the PD is as follows:
[0007] in, Indicates line loss. This indicates the output voltage of the PSE. This indicates the voltage returned to the PD input terminal; The calculation expression for estimating line loss based on the output current and cable impedance of the PSE output terminal is as follows:
[0008] in, This indicates the output current at the PSE output terminal. This indicates the cable impedance.
[0009] The cable impedance acquisition method includes two types: The first type involves applying two different test currents I1 and I2, measuring the corresponding voltages V1 and V2 of the cable, and then calculating the cable impedance as follows:
[0010] The second method is to directly estimate the impedance using pre-stored cable impedance or based on the cable length and type configured by the user.
[0011] Furthermore, the calculation expression for the target output voltage in step S5 is as follows:
[0012] in, Indicates the target output voltage. V_margin represents the input voltage expected by the PD, and V_margin is the safety margin.
[0013] Furthermore, if the PD terminal supports voltage feedback and an abnormal increase in the voltage of the PD input terminal is detected during feedback, the voltage of the PD input terminal is immediately reduced to within the safe power supply voltage.
[0014] Furthermore, if the PD is detected to be in a low-power state, the output voltage of the PSE is adjusted to a preset low-power voltage.
[0015] Furthermore, when the PD enters sleep mode or is disconnected, the PSE will shut down the output or adjust to the sustaining voltage.
[0016] Secondly, this application proposes a dynamic adjustment device for the output voltage of a power supply equipment, including a core control unit, a PD identification and negotiation module, an adjustable DC-DC module, a voltage and current detection module, and a communication interface. The PD identification and negotiation module is used to classify the powered equipment, determine the coarse power level of the powered equipment, perform fine power negotiation with the powered equipment through a link layer negotiation protocol, obtain the power negotiation result, exchange voltage information capability identifiers, and feed back the power negotiation result to the core control unit. The adjustable DC-DC module is used to receive instructions from the core control unit and adjust the output voltage of the power supply equipment. The voltage and current detection module is used to detect the output voltage and output current of the PSE and feed them back to the core control unit. The communication interface is used to transmit the feedback data from the powered equipment. The core control unit is used to receive data from the PD identification and negotiation module, the voltage and current detection module, and the communication interface and issue instructions.
[0017] This application proposes a method and apparatus for dynamic adjustment of the output voltage of a power supply device. By estimating line loss and monitoring the output voltage of the PSE and the input voltage of the PD, the PSE output voltage is adaptively adjusted to ensure that it matches the voltage required by the PD and extends the service life of the PSE and PD devices. Attached Figure Description
[0018] Figure 1 This is a flowchart illustrating a method for dynamically adjusting the output voltage of a power supply device according to an embodiment of this application. Figure 2 This is a schematic diagram of a dynamic voltage adjustment device for a power supply device according to an embodiment of this application. Figure 3 This is a module functional structure diagram of a dynamic adjustment device for the output voltage of a power supply device according to an embodiment of this application; Figure 4 This is a control flowchart of a dynamic adjustment device for the output voltage of a power supply device according to an embodiment of this application. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0020] Example 1 This embodiment provides a method for dynamically adjusting the output voltage of a power supply device, and the flowchart of the method is as follows. Figure 1 As shown, it includes the following specific content: S1: The PSE detects the PD with a preset safe voltage and classifies the PD to determine the approximate power level of the PD. S2: Establish a data link, negotiate a protocol at the link layer and conduct fine power negotiation with the PD based on the coarse power level to obtain the power negotiation result, and exchange voltage information and capability identifiers at the same time. It should be noted that the link layer negotiation protocol in step S2 includes the LLDP protocol, and the fine power negotiation includes the powered device transmitting its actual power requirements and voltage tolerance range, and the power supply device reporting its own power supply capability boundaries. The voltage information capability identifier in step S2 is used to determine whether the PD supports voltage information backhaul.
[0021] In one specific embodiment, steps S1 and S2 belong to the initial power-on and negotiation phase, and the preset safety voltage adopts a low safety voltage such as 15V.
[0022] S3: Based on the power negotiation results, the PSE is powered by a preset standard voltage. Read the PSE's output voltage and output current. In one specific embodiment, step S3 belongs to the power supply standard establishment stage, and the preset standard voltage starts with 48V.
[0023] S4: Estimate line loss based on the output current and cable impedance or based on the output voltage and voltage feedback at the PD input terminal; It should be noted that if the PD supports voltage information feedback, then step S4 estimates the line loss based on the output voltage of the PSE and the voltage at the input of the PD; otherwise, it estimates the line loss based on the output current at the output of the PSE and the cable impedance.
[0024] The calculation expression for line loss estimation based on the output voltage of the PSE and the input voltage of the PD is as follows:
[0025] in, Indicates line loss. This indicates the output voltage of the PSE. This indicates the voltage returned to the PD input terminal; The calculation expression for estimating line loss based on the output current and cable impedance of the PSE output terminal is as follows:
[0026] in, This indicates the output current at the PSE output terminal. This indicates the cable impedance.
[0027] The cable impedance acquisition method includes two types: The first type involves applying two different test currents I1 and I2 (by slightly adjusting the load or requesting the PD to enter different modes), measuring the corresponding voltages V1 and V2 of the cable, and then calculating the cable impedance.
[0028] The second method is to estimate the impedance directly from the pre-stored cable impedance or based on the user-configured cable length and type (National Standard GB / T 3956-2008 specifies the number of single wires, dimensions, and resistance values of conductors for cables with cross-sectional areas ranging from 0.5 mm² to 2500 mm²).
[0029] S5: Calculate the target output voltage based on the estimated line loss and adjust the PSE output voltage to make the PSE output voltage approach the target output voltage.
[0030] It should be noted that the calculation expression for the target output voltage in step S5 is as follows:
[0031] in, Indicates the target output voltage. V_margin represents the input voltage expected by the PD, and V_margin is the safety margin.
[0032] In one specific embodiment, the PD is expected to have an input voltage of 42V with a safety margin of 1V.
[0033] It should be noted that if the PD terminal supports voltage feedback and an abnormal increase in the voltage of the PD input terminal is detected, the voltage of the PD input terminal should be immediately reduced to within the safe power supply voltage.
[0034] If the PD is detected to be in a low-power state, the output voltage of the PSE will be adjusted to the preset low-power voltage.
[0035] When the PD enters sleep mode or is disconnected, the PSE will shut down the output or adjust to the sustaining voltage.
[0036] In a specific embodiment, the dynamic adjustment and optimization are as follows: During normal power supply, the output voltage of the PSE is fine-tuned by monitoring the output current of the PSE in real time or periodically and estimating the line loss. The core objective is to keep the input voltage of the PD stable at a safe voltage, such as 42V. When a significant change in the output current of the PSE is detected (meaning a change in the power consumption of the PD), the fine-tuning cannot handle the change, and the target output voltage needs to be recalculated and adjusted.
[0037] To ensure system stability, it is necessary to continuously monitor the PSE's output voltage V_local and output current I_out, as well as the PD's input voltage V_remote. If an abnormal increase in V_remote is detected (which may indicate that the cable has been shortened or the PD has been disconnected), the voltage should be immediately reduced to a safe range to prevent the next connected PD from being subjected to overvoltage.
[0038] Light load and idle state optimization: When the PD is detected to be in a low-power state (the PSE output current is very small), the system can automatically reduce the output voltage to a level slightly higher than the minimum operating voltage required by the PD. When the PD enters sleep mode or is disconnected, the PSE can shut down the output or reduce the voltage to the sustaining voltage.
[0039] This invention improves the energy efficiency and reliability of the PoE system by automatically adjusting the output voltage of the PSE device, minimizing energy consumption due to line loss, and extending the service life of the PSE and PD devices. Through dynamic compensation, it increases the power supply distance and enables the system to adapt to differences in transmission cables of varying quality and PD standards.
[0040] Example 2 This embodiment provides a dynamic adjustment device for the output voltage of a power supply device. The architecture diagram of the device is shown below. Figure 2 As shown, it includes a core control unit, a PD identification and negotiation module, an adjustable DC-DC module, a voltage and current detection module, and a communication interface. This device is usually integrated inside the PSE equipment, providing independent group control voltage regulation capability for each PoE port.
[0041] The functional structure diagram of each module of the device is shown in Figure 3. The core control unit is used to receive data from the PD identification and negotiation module, the voltage and current detection module and the communication interface and issue instructions. In one specific embodiment, the main control chip is selected from ARM Cortex-M series MCUs (such as STM32G4 series) that integrate multi-channel high-precision ADC and DAC, or dedicated PSE management ASICs (such as Microchip PD-692x series). This main control chip has powerful computing capabilities, supports floating-point operations, and is used to run PID control algorithms and line loss models; it has built-in flash storage for cable impedance, system adjustment history, and data for PD level identification.
[0042] The PD identification and negotiation module is used to classify PDs by level, determine the coarse power level of PDs, conduct fine power negotiation with PDs through link layer negotiation protocol, obtain power negotiation results and exchange voltage information capability identifiers, and feed back the power negotiation results to the core control unit. In one specific embodiment, the PD identification and negotiation module reuses the physical layer classification function of the standard PoE chip to achieve PD level classification. It is responsible for parsing and generating a PD model and PD voltage report (such as the PD input voltage V_remote, the maximum required voltage at the PD terminal, the minimum operating voltage of the PD, etc.).
[0043] The adjustable DC-DC module is used to receive instructions from the core control unit and adjust the PSE output voltage; In a specific embodiment, key components in the adjustable DC-DC module include a controller, power MOSFETs, inductors, and capacitors. For example, the controller may be an LTC3871 bidirectional buck or boost switching regulator, which can perform voltage regulation from 100V to 30V in buck mode and from 30V to 100V in boost mode based on a control signal. The power MOSFET may be a low-Rds(on) N-channel MOSFET to reduce switching losses. The inductors and capacitors may be low-loss, high-saturation-current inductors and low-ESR ceramic capacitors to ensure low output ripple and fast response.
[0044] The voltage and current detection module is used to detect the output voltage and output current of the PSE and feed them back to the core control unit. In one specific embodiment, the voltage and current detection module employs a high-precision ADC acquisition circuit to sample the voltage and current at 1000 samples per second, facilitating rapid capture of sudden current surges. Voltage sampling utilizes a differential amplifier (INA2181) + high-precision ADC to measure the output voltage V_local at the PSE terminal. Current sampling employs an integrated current-sensing intelligent power switch (TPS23880).
[0045] The communication interface is used to transmit the PD's return data; In one specific embodiment, the communication interface depends on the amount of interface resources available on the main control chip. Having a rich variety of communication interface types can ensure communication between modules. For example, I2C / SPI is used to communicate with voltage and current detection modules and adjustable DC-DC modules. MII / RMII interfaces are used to exchange LLDP data with PSE and PD devices.
[0046] Example 3 This embodiment will describe the process of the device dynamically adjusting the voltage in order to further understand the device proposed in this application. The control flow of the device is as follows: Figure 4 As shown, the steps to achieve dynamic voltage adjustment are as follows: When the PSE port is powered normally, read the PSE output voltage V_local, PSE output voltage I_out, and the returned PD input voltage V_remote value; calculate the target output voltage V_target; send an adjustment command to the adjustable DC-DC module to make V_local approach V_target; wait for the adjustment period T (e.g., 100ms) and simultaneously listen for current surge events; execute fault diagnosis and protection logic.
[0047] To ensure the safe use of PSE / PD equipment and maximize the service life of the PoE system, the following safety strategies are proposed and the entire power supply system is optimized.
[0048] Ⅰ Light load voltage reduction: When I_out is detected to be continuously below the threshold (e.g., 0.1A) for more than 10 seconds, the expected operating voltage V_pd_desired of the PD is gradually reduced from 42V to the minimum allowable value (e.g., 38V), and V_target is recalculated.
[0049] II. Sudden Change Response: When the rate of change of I_out |dI / dt| exceeds the threshold, a voltage recalculation and adjustment is immediately triggered.
[0050] III. Safety Check: V_target needs to be limited to the range of [V_min, V_max] (e.g., between 44V and 57V); if V_remote rises abnormally, it is determined that the cable is short-circuited or the PD is abnormal, and power reduction or power-off protection is immediately implemented.
[0051] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A method for dynamically adjusting the output voltage of a power supply device, characterized in that, Includes the following steps: S1: The power supply equipment detects the powered equipment with a preset safe voltage, classifies the powered equipment by level, and determines the approximate power level of the powered equipment. S2: Establish a data link, negotiate a protocol at the link layer and perform fine power negotiation with the powered device based on the coarse power level to obtain the power negotiation result, and exchange voltage information and capability identifiers at the same time. S3: Based on the power negotiation results, the power supply device supplies power at a preset standard voltage, and reads the output voltage and output current of the power supply device; S4: Estimate line loss based on the output current and cable impedance or based on the output voltage and voltage feedback at the PD input terminal; S5: Calculate the target output voltage based on the estimated line loss and adjust the output voltage of the power supply equipment to make the output voltage of the power supply equipment approach the target output voltage.
2. The method for dynamically adjusting the output voltage of a power supply device according to claim 1, characterized in that, The fine power negotiation in step S2 includes the actual power demand and voltage tolerance range transmitted by the powered equipment, and the power supply capability boundary fed back by the power supply equipment.
3. The method for dynamically adjusting the output voltage of a power supply device according to claim 1, characterized in that, The voltage information capability identifier mentioned in step S2 is used to determine whether the powered device supports voltage information backhaul. If the powered device supports voltage information backhaul, then step S4 estimates the line loss based on the output voltage of the power supply device and the voltage at the input end of the powered device; otherwise, it estimates the line loss based on the output current of the power supply device and the cable impedance.
4. The method for dynamically adjusting the output voltage of a power supply device according to claim 3, characterized in that, The calculation expression for estimating line loss based on the output voltage of the power supply equipment and the input voltage of the power receiving equipment is as follows: in, Indicates line loss. This indicates the output voltage of the PSE. This indicates the voltage at the input terminal of the receiving device being transmitted back. The calculation expression for estimating line loss based on the output current of the power supply equipment and the cable impedance is as follows: in, This indicates the output current at the output terminal of the power supply equipment. This indicates the cable impedance.
5. The method for dynamically adjusting the output voltage of a power supply device according to claim 4, characterized in that, The cable impedance is obtained using two methods: the first method involves applying two different test currents I1 and I2, measuring the corresponding voltages V1 and V2 of the cable, and then calculating the cable impedance. The second method is to directly estimate the impedance using pre-stored cable impedance or based on the cable length and type configured by the user.
6. The method for dynamically adjusting the output voltage of a power supply device according to claim 4, characterized in that, The calculation expression for the target output voltage in step S5 is: in, Indicates the target output voltage. V_margin represents the input voltage expected by the PD, and V_margin is the safety margin.
7. The method for dynamically adjusting the output voltage of a power supply device according to claim 3, characterized in that, If the power receiving equipment supports voltage feedback and an abnormal increase in the voltage at the input terminal of the power receiving equipment is detected, immediately reduce the voltage at the input terminal of the power receiving equipment to within the safe power supply voltage range.
8. The method for dynamically adjusting the output voltage of a power supply device according to claim 7, characterized in that, If the powered device is detected to be in a low-power state, adjust the output voltage of the power supply device to the preset low-power voltage.
9. The method for dynamically adjusting the output voltage of a power supply device according to claim 8, characterized in that, When the powered device is disconnected or enters sleep mode, the power supply device will shut down its output or adjust to maintain voltage.
10. A dynamic voltage adjustment device for power supply equipment, characterized in that, The system includes a core control unit, a PD identification and negotiation module, an adjustable DC-DC module, a voltage and current detection module, and a communication interface. The PD identification and negotiation module is used to classify the powered equipment, determine the coarse power level of the powered equipment, conduct fine power negotiation with the powered equipment through a link layer negotiation protocol, obtain the power negotiation result, exchange voltage information capability identifiers, and feed back the power negotiation result to the core control unit. The adjustable DC-DC module is used to receive instructions from the core control unit and adjust the output voltage of the power supply equipment. The voltage and current detection module is used to detect the output voltage and output current of the PSE and feed them back to the core control unit. The communication interface is used to transmit the feedback data from the powered equipment. The core control unit is used to receive data from the PD identification and negotiation module, the voltage and current detection module, and the communication interface and issue instructions.