POE-based power supply method and PSE

Patent metadata

Field	Value
Publication number	US-10027494-B2
Application number	US-201615362910-A
Country	US
Kind code	B2
Filing date	Nov 29, 2016
Priority date	Nov 30, 2015
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A PoE-based power supply method and PSE. The method includes: after PSE supplies power to a PD, determining, by the PSE, a line voltage drop across a network cable between the PSE and the PD; and when the line voltage drop across the network cable is greater than a line voltage drop threshold, sending, by the PSE, a first Ethernet packet to the PD, so that the PD decreases load of the PD according to instruction information instructing the PD to decrease load power consumption and included in the first Ethernet packet. This ensures that a voltage received by the PD can satisfy a power requirement of the load of the PD, and further ensures that the PD can work normally.

First claim

What is claimed is:

1. A Power over Ethernet (PoE)-based power supply method implemented by a power sourcing equipment (PSE), the method comprising:
determining, before supplying power to a powered device (PD), an impedance of a network cable between the PSE and the PD;
determining a current in the network cable after supplying power to the PD;
using a product of the current and the impedance as a line voltage drop across the network cable;
and
sending a first Ethernet packet to the PD when the line voltage drop is greater than a line voltage drop threshold, wherein the first Ethernet packet comprises a first instruction for instructing the PD to decrease a load power consumption.

2. The method of claim 1 , wherein the determining the impedance comprises:
determining a length of the network cable;
determining a category of the network cable by:
determining a first correspondence between output powers and signal-to-noise ratios (SNRs) of the network cable; and
determining the category according to correspondences between output powers and SNRs of various network cable categories on one hand and the first correspondence on another hand;

determining, according to the category, an impedance per unit length corresponding to the category; and
using a product of the impedance per unit length and the length as the impedance of the network cable.

3. The method of claim 2 , wherein before sending the first Ethernet packet to the PD, the method further comprises determining a current change rate of the network cable, wherein the current change rate indicates a change rate threshold of the load power consumption, wherein the first Ethernet packet further comprises the current change rate.

4. The method of claim 3 , wherein the determining the current change rate comprises:
determining a maximum communication bandwidth corresponding to the network cable category;
determining a noise voltage threshold of the network cable according to a port rate of the PSE, the maximum communication bandwidth, and an output voltage outputted by the PSE to the PD;
adjusting, after the PSE outputs the output voltage to the PD, a voltage value of the output voltage according to a specified unit time;
measuring, after the PSE outputs the output voltage to the PD, a noise voltage of the network cable after each voltage adjustment, till until a measured noise voltage of the network cable is equal to the noise voltage threshold; and
determining a current change rate of the network cable within the specified unit time in a last adjustment process.

5. The method of claim 4 , wherein the noise voltage threshold makes the following formula hold true:

U
N

=

U
O

2

C
W

-
1

wherein U N is the noise voltage threshold, U O is the output voltage, C is the port rate, and W is the maximum communication bandwidth.

6. The method of claim 1 , wherein before the PSE supplies the power to the PD, the method further comprises:
detecting a current load power consumption of the PD;
classifying the PD according to the current load power consumption to determine a class of the PD;
determining, according to the class, a maximum-load power consumption of the PD and a maximum output voltage outputted by the PSE to the PD;
determining a current overload threshold for the network cable according to the maximum-load power consumption of the PD, the impedance of the network cable, and the maximum output voltage; and
using the current overload threshold to control a power supply for the PD.

7. The method of claim 1 , further comprising:
sending a first voltage impulse to the PD;
detecting a second voltage impulse received by the PD;
determining a network cable insertion loss of the network cable according to the first voltage impulse and the second voltage impulse;
determining, according to a correspondence between insertion losses and temperatures, a network cable temperature corresponding to the network cable insertion loss; and
sending a second Ethernet packet to the PD when the network cable temperature is greater than a network cable temperature threshold, wherein the second Ethernet packet comprises a second instruction instructing the PD to decrease the load power consumption.

8. A power sourcing equipment (PSE) comprising:
a PSE chip configured to supply power to a powered device (PD) and determine, after the PSE chip supplies power to the PD, a current in a network cable between the PSE and the PD; and
a processor coupled to the PSE chip and configured to:
determine an impedance of the network cable before the PSE chip supplies power to the PD;
use a product of the current and the impedance as a line voltage drop across the network cable;
and
send a first Ethernet packet to the PD when the line voltage drop across the network cable is greater than a line voltage drop threshold, wherein the first Ethernet packet comprises an instruction for instructing the PD to decrease a load power consumption.

9. The PSE of claim 8 , wherein the processor is further configured to:
determine a network cable category of the network cable by:
determining a first correspondence between output powers and signal-to-noise ratios (SNRs) of the network cable; and
determining the category according to correspondences between output powers and SNRs of various network cable categories on one hand and the first correspondence on another hand;

determine, according to the category, an impedance per unit length corresponding to the category; and
use a product of the impedance per unit length and the length as the impedance of the network cable.

10. The PSE of claim 9 , wherein the PSE chip is further configured to:
determine the length; and
detect and obtain the SNRs of the network cable under the output powers.

11. The PSE of claim 10 , wherein before sending the first Ethernet packet to the PD, the processor is further configured to determine a current change rate of the network cable, wherein the current change rate indicates a change rate threshold of the load power consumption, and wherein the first Ethernet packet further comprises the current change rate.

12. The PSE of claim 11 , wherein the processor is further configured to:
determine a maximum communication bandwidth corresponding to the network cable category; and
determine a noise voltage threshold of the network cable according to a port rate of the PSE, the maximum communication bandwidth, and an output voltage outputted by the PSE to the PD,
wherein the PSE chip is further configured to:
adjust, after outputting the output voltage to the PD, a voltage value of the output voltage according to a specified unit time; and
measure, after outputting the output voltage to the PD, a noise voltage of the network cable after each voltage adjustment until a measured noise voltage of the network cable is equal to the noise voltage threshold, and

wherein the processor is further configured to determine a current change rate of the network cable within the specified unit time in a last adjustment process.

13. The PSE of claim 12 , wherein the noise voltag

Assignees

• Huawei Tech Co Ltd

Inventors

• Yang Chuanfeng

Classifications

• H04L12/10 Primary

  Current supply arrangements · CPC title

• H04L12/40045

  Details regarding the feeding of energy to the node from the bus · CPC title

• H04L41/0813

  characterised by the conditions triggering a change of settings · CPC title

• H04L41/08

  Configuration management of networks or network elements (address allocation H04L61/50) · CPC title