WO2017031711A1 - 避免磁饱和提高无线充电效率 - Google Patents

避免磁饱和提高无线充电效率 Download PDF

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WO2017031711A1
WO2017031711A1 PCT/CN2015/088086 CN2015088086W WO2017031711A1 WO 2017031711 A1 WO2017031711 A1 WO 2017031711A1 CN 2015088086 W CN2015088086 W CN 2015088086W WO 2017031711 A1 WO2017031711 A1 WO 2017031711A1
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magnetic saturation
wireless charging
current
saturation state
loss
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PCT/CN2015/088086
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English (en)
French (fr)
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于保华
胡颖
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苏州宝润电子科技有限公司
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Priority to PCT/CN2015/088086 priority Critical patent/WO2017031711A1/zh
Publication of WO2017031711A1 publication Critical patent/WO2017031711A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/14—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
    • H02J7/16—Regulation of the charging current or voltage by variation of field
    • H02J7/20—Regulation of the charging current or voltage by variation of field due to variation of continuously variable ohmic resistor

Definitions

  • Magnetic saturation is a physical property of a magnetic material, which means that the magnetic flux passing through the magnetically permeable material cannot be infinitely increased due to the limitation of the physical structure, thereby maintaining a certain number of states.
  • Wireless charging technology also known as non-contact inductive charging, is derived from wireless power transmission technology, using near-field sensing, inductive coupling, and energy is transmitted from a power supply device to a powered device that uses the received Energy charges the battery and at the same time serves itself.
  • the invention aims to solve the magnetic saturation phenomenon under the electromagnetic induction technology and is applicable to the Qi standard and the PMA standard.
  • the process of transmitting power by two devices does not require the passage of any physically present tangible wires.
  • the energy is transferred from the transmitting end to the receiving end, the currents of the coils used by the two devices to sense each other and then transfer energy will continuously increase.
  • the current exceeds a certain value, the magnetic saturation phenomenon may occur in the emission.
  • the end or the receiving end causes energy transmission loss.
  • the invention aims to detect and avoid magnetic saturation loss during wireless charging and improve wireless charging efficiency.
  • the magnetic saturation curve depicts standard steel, silicon steel (containing 2.5% silicon), mild steel castings, tungsten steel, magnet steel, pig iron, nickel (99%), cast cobalt and magnetite (Fe2O3).
  • Magnetic saturation curves of nine magnetic materials It can be concluded from Fig. 1 that after the magnetic field strength H of the external magnetic field is increased to a certain value, it is impossible to continuously increase the magnetic induction intensity B of the magnetic material regardless of how H continues to enhance, due to the vacuum before B reaches a flat saturated state.
  • Magnetic permeability, B has a slowly increasing process. That is, as shown in Figure 1, the magnetic saturation curve of each magnetic material can be divided into three stages, 110 - the non-magnetic saturation stage, 130 - the magnetic saturation stage, 120 - the transition stage, that is, the unmagnetic saturation stage 110 to the transition phase of the magnetic saturation phase 130.
  • the present invention is directed to maintaining the wireless charging process operating at a 110-non-magnetic saturation stage. When the magnetic saturation state occurs, the current of the wireless charging transmitter is continuously reduced until the software algorithm detects that the magnetic saturation phenomenon no longer occurs.
  • Figure 1 is a magnetic saturation curve
  • FIG. 2 is the wireless charging system framework
  • Figure 3 is a flow chart for avoiding magnetic saturation
  • FIG. 2 depicts a system framework for wireless charging of a mobile terminal through a charging base.
  • the mobile terminal can be a portable electronic product that can be wirelessly charged by an ordinary mobile phone, a smart phone, a handheld computer, a pad, or the like.
  • the charging base detects the mobile terminal (the distance of the mobile terminal from the charging base is less than 1 cm)
  • the energy conversion unit of the transmitting end supplies energy to the transmitting coil to generate a magnetic field.
  • the magnetic field energy is received by the receiving coil and converted into a current, while the receiving energy unit supplies power to the load of the mobile terminal.
  • Both the transmitter and receiver have a communication and control unit that senses and manages the wireless charging process.
  • the mobile terminal can detect the receiving voltage and the receiving current of the receiving end (ie, the voltage across the receiving coil and the current flowing through the transmitting coil) and provide it to the transmitting end, and then the charging base will calculate the transmission of the receiving end by the communication and control unit.
  • Energy (P I * V)
  • W2 decrease in emission current I TX end fixed ratio - the transmitter current I TX fixed value needs to be reduced, i.e. decreases according to a fixed ratio, for example, a new I TX I TX reduced to the original 90% or 80% of the original I TX , or less than 100% of the original I TX any percentage of the case.
  • ⁇ Loss is proportional to the emitter current I TX - determine whether the change in energy loss ⁇ Loss is proportional to the change in the current I TX at the transmitter, for example if I TX is reduced to 90% of I TX , ie ⁇ I TX It is 10%, then it is necessary to calculate whether the proportion of Loss in W1 in W6 is also nearly 10%.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

一种避免磁饱和提高无线充电效率的方法，包括判断无线充电为磁饱和状态（W0）；逐渐按固定值降低发射端电流的数值直到无线充电系统退出磁饱和状态（W2）；当无线充电系统已经不在磁饱和状态时，设置发射端电流最大值Imax（W8），充电基座对同一移动终端同一次充电过程发射端电流不能大于最大值Imax。本方法在无线充电过程中检测并避免磁饱和损耗，提高了无线充电效率。

Description

避免磁饱和提高无线充电效率
技术领域：磁饱和是磁性材料的一种物理特性，指的是导磁材料由于物理结构的限制，所通过的磁通量无法无限增大，从而保持在一定数量的状态。无线充电技术(Wireless charging technology)，又称作非接触式感应充电，源于无线电力输送技术，利用近场感应，电感耦合，由供电设备将能量传送至用电装置，该装置使用接收到的能量对电池充电，并同时供其本身运作之用。主流的无线充电标准有三种：Qi标准、PMA标准、A4WP标准。磁饱和现象在上述三种无线充电标准中均有可能出现。本发明旨在解决电磁感应技术下的磁饱和现象，适用于Qi标准和PMA标准。
背景技术:基于无线充电系统框架，两种设备(一般指能量发射端和能量接收端)传输电力的过程不需要通过任何物理存在的有形电线。当能量从发射端向接收端转移的过程中，这两种设备用来相互感应然后传递能量的线圈中的电流会不断增大，当电流超过一定数值，磁饱和现象就有可能会发生在发射端或接收端，造成能量传输损耗。本发明旨在无线充电过程中检测并避免磁饱和损耗，提高无线充电效率。
发明内容：在磁饱和的状态下，磁渗透性不再随着磁场变大而增加，不同材料的磁饱和曲线是不同的，磁渗透性有自身的最大值。如图1所示，磁饱和曲线图描绘了标准钢板、硅钢板(含硅2.5％)、软钢铸件、钨钢、磁铁钢、生铁、镍(99％)、铸造钴和磁铁矿(Fe2O3)九种磁性材料的磁饱和曲线图。由图1可得出，当外部磁场的磁场强度H增强到一定数值以后，无论H再如何继续增强都不可能使磁性材料的磁感应强度B继续快速增大，在B达到持平饱和状态之前由于真空磁渗透性，B有一段缓慢增大的过程。即图1中所标示，每种磁性材料的磁饱和曲线都可以分为三个阶段，110——未磁饱和阶段，130——磁饱和阶段，120——转折阶段，即从未磁饱和阶段110到磁饱和阶段130的过渡阶段。本发明旨在将无线充电过程保持在110——未磁饱和阶段下工作。当出现磁饱和状态，不断地减小无线充电发射端电流，直到软件算法检测到磁饱和现象不再发生为止。
附图说明：下面结合附图和实施对本发明进一步说明。
图1是磁饱和曲线图
图2是无线充电系统框架
图3是避免磁饱和流程图
具体实施方式：在介绍避免磁饱和的方法之前，我们先了解一下无线充电系统框架，如图2描绘了一个移动终端通过充电基座进行无线充电的系统框架。移动终端可以是普通手机、智能手机、手持电脑、Pad等可以电磁感应无线充电的便携电子产品。当充电基座检测到移动终端时(移动终端距离充电基座距离小于1cm)，发射端的能量转换单元提供能量给发射线圈，产生磁场。在接收端，磁场能量由接收线圈接收并转变为电流，同时，接收能量单元向移动终端的负载供电。发射端和接收端都有一个通信和控制单元，负责感应和管理无线充电过程。在无线充电过程中，充电基座可以通过检测发射端的发射电压和发射电流(即发射线圈两端的电压和流过发射线圈的电流)计算发射端的传输能量(P＝I*V)。同理，移动终端可以通过检测接收端的接收电压和接收电流(即接收线圈两端的电压和流过发射线圈的电流)并提供给发射端，然后由充电基座将由通信和控制单元计算接收端的传输能量(P＝I*V)，并计算能量损耗Loss为发射端的传输能量减去接收端的传输能量(Loss＝PTX-PRX)。
本发明在避免磁饱和和提高无线充电效率的流程如图3所示：
W0.判断无线充电为磁饱和状态——此流程开始于无线充电的状态被判断为在磁饱和状态，即当W7的判断结果为否NO时。
W1.计算新的损耗Lossnew，设置Loss＝Lossnew——按照上述计算能量损耗Loss的方法计算新的损耗Lossnew，并将数值存储在Loss中。
W2.降低发射端电流ITX固定比例——发射端电流ITX需要被减少固定数值，即根据固定比例降低，例如新的ITX减少为原ITX的90％，或者原ITX的80％，或者小于100％的原ITX任意一个百分比例。
W3.读发射端电压VTX、电流ITX——读取发射端电压和电流，计算发射端传输能量PTX＝ITX*VTX。W4.读接收端电压IRX、电流IRX——读取接收端电压和电流，计算接收端传输能量PRX＝IRX*VRX。W5.计算新的损耗Lossnew——计算新的损耗Lossnew＝PTX-PRX。
W6.计算△Loss＝Loss-Lossnew——根据公式计算能量损耗的变化。
W7.△Loss是否与发射端电流ITX等比例——判断能量损耗的变化△Loss是否与发射端电流ITX的变化等比例，例如如果ITX减少为ITX的90％，即△ITX是10％，那么需要计算是否在W6中△Loss所占W1中Loss的比例是否也将近10％。
W8.不在磁饱和状态，设置电流最大值Imax——当W7判断结果为是YES，表明无线充电已经不在磁饱和状态，设置发射端电流最大值Imax为当前ITX。充电基座对同一移动终端同一次充电过程发射端电流不能大于Imax，从而避免再次进入磁饱和状态造成能量损耗。
Figure PCTCN2015088086-appb-000001

Claims (3)

  1. 根据计算无线充电过程中能量传输的损耗变化与发射端电流的变化是否成比例，判断无线充电系统是否进入磁饱和状态。
  2. 基于权利1的要求，逐渐按固定值降低发射端电流的数值直到无线充电系统退出磁饱和状态。
  3. 基于权利1和权力2，记录退出第一次磁饱和状态的发射端电流为Imax，充电基座对同一移动终端同一次充电过程发射端电流不能大于Imax，从而避免再次进入磁饱和状态造成能量损耗。
    Figure PCTCN2015088086-appb-100001
PCT/CN2015/088086 2015-08-26 2015-08-26 避免磁饱和提高无线充电效率 WO2017031711A1 (zh)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103229258A (zh) * 2010-09-16 2013-07-31 Nec卡西欧移动通信株式会社 非接触电力传输设备
WO2015069780A1 (en) * 2013-11-06 2015-05-14 Blackberry Limited Energy transfer optimization by detecting and mitigating magnetic saturation in wireless charging with foreign object detection
CN104993563A (zh) * 2015-08-12 2015-10-21 苏州宝润电子科技有限公司 避免磁饱和提高无线充电效率

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103229258A (zh) * 2010-09-16 2013-07-31 Nec卡西欧移动通信株式会社 非接触电力传输设备
WO2015069780A1 (en) * 2013-11-06 2015-05-14 Blackberry Limited Energy transfer optimization by detecting and mitigating magnetic saturation in wireless charging with foreign object detection
CN104993563A (zh) * 2015-08-12 2015-10-21 苏州宝润电子科技有限公司 避免磁饱和提高无线充电效率

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