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    October 04

    Wireless Power

    Wireless communication, also wireless power
    Wireless does make life easy

     

    Comments (18)

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    Bin Fanwrote:
    同学你到底算是八卦男还是算是学术男呢? 我陷入了沉思 ...
    Oct. 23
    Jun Zhangwrote:
    It turns out that there are commercial products already: http://gigaom.com/2009/10/23/wireless-power-is-still-pretty-useless/
    Oct. 23
    i was talking about this: http://www.themirasoleffect.com/
    but yeah, qualcomm definitely has a lot of money to burn and one of those projects may actually launch into something big.
    Oct. 14
    Jun Zhangwrote:
    Previously, I heard from someone who did intern in Qualcomm that they are doing something on 3D monitor, maybe just this one: http://www.allbusiness.com/electronics/computer-electronics-manufacturing/6297476-1.html
    also very interesting.
    Oct. 13
    wireless charging确实是一个attractive的东东。要说这个东西不可能没人想过要做,归根到底可能还是安全和损耗的问题。距离问题本质上也是个损耗问题, 如果能做到10m以内50%,那么还是很不错的。不过我肯定还是不会着急用这个玩意的,junjun你先试用一下先,哈哈

    不过说起qualcomm做的很多东西还是很impressive的,感觉qualcomm现在和google有点像,CDMA那边靠专利抓了一大笔钱,现在就有闲情来搞各种R&D。前几个月看到他们在做的一个新一代显示器的project, 也很fancy的样子。
    Oct. 12
    是不是原理跟微波炉差不多啊?
    Oct. 8
    Yan Liwrote:
    qualcomm 做成盘子的样子只是方便你放置手机啊啥的,不是说一定要接触到才能开始充电滴。。。你拿着手机靠近那个‘盘子’其实就已经开始充电了,可是你总不想在那儿一直举着手机吧。。。所以说确实是wireless charging啦,好像他们说是充满电要半个小时还是啥的,忘了,反正不会比现在的充电速度慢很多。但是。。。如果放了几个手机的话当然就慢下去了。。。
    Oct. 7
    Jun Zhangwrote:
    well, I just find it's interesting. Glad to see lots of replies on this post. If it works well, i.e. omni-directional, power efficient, low cost, then absolutely it will play a role. Let's see how good we can make it.
    Oct. 7
    还是阿军这边的学术氛围浓hoho~
    to Yingda同学:谢谢提醒,我刚检查了一下笔记本电源,之前把输入当输出了,输入是100-240~ 1.6A,输出是65W。BTW,这么着输入是160W了,难道我的开关电源耗了差不多100W还是我算错了。。。OMG。。。
    还有两个问题:1是功率和距离的问题,具体数值记不得了,感应线圈获得的功率是随距离成指数递减的,正对情况下,大概两个平行线圈的距离是线圈边长的1/10以内的情况下,功率传输大概可以达到1:1这个数量级。就是说,如果50cm边长的线圈,两个线圈正对,并且距离5cm以内,大概你发射4W或许可以接收4W,线圈匝数和电阻损耗啥的暂不考虑。然后,功率传输效率就是随着距离成指数递减了,大概距离50cm的情况下获得的功率<0.4W.上述分析还是发射线圈和感应线圈的尺寸都是50cm的情况。
    第二个问题是全方向性:全方向的线圈是有的,基本上就是做成8字形的天线,然后要有一堆电路控制不同回路的电流相位。05年底的时候国内公司买过一个,8万还是12万 RMB。给手机冲个电实在成本太高。。。

    目前这种技术的应用在超市防盗门,RFID识别主要是物流领域,高速公路自动收费等。

    Oct. 7
    if it is not omni-directional, then maybe it is nothing more than an eye-catcher...

    but i bet to disagree that one needs to provide ~100W wirelessly to make the technology useful. most cellphones can be charged at less than 5W input. if you think about it, standard USB provides 5V at maximum <1A: u can use that to charge almost every mobile device. in fact, ~2W is probably enough to get most phone going, just charging slower.

    the big turn-off is that the thing being one-directional, which i am not sure though. if they can make it omni-directional, then there are still tremendous potentials at <4W power. not that you can use it to light up a light bulb, but that is not what makes this attractive anyway. i will be all over it if it can charge my mobile device SAFELY (a.k.a, without burning my brain....) without wires.

    btw: you should check your numbers, i seriously doubt any 12inch laptop runs at 160W, you will be burning yourself if you put such laptop on your lap...:-) my x60 runs at 65W peak, and most of time it is <30W.
    Oct. 6
    昨天和朋友讨论了一下这个问题,目前得出两点结论:
    1、没有找到有价值的应用领域,通俗点说:没用。
    2、安全性是大问题,以我12寸的笔记本为例,功率160W左右,如果能够满足这种供电需求,就要求无线power传输功率大于这个数值。我以前做RFID,13.56MHz的美国安全标准是4W,欧洲安全标准是10W。在这种耦合传输的无线传输中(散射的功率要更大),除了手机这种小玩意儿大概可以在4W以下。说白了。。。实在没啥用。。。
    努力找找无人环境中的应用似乎还有点前途。。。

    to楼下的Yingda同学,这个video演示的也不是omni—directional,两个线圈必须平行正对,这种情况在RFID领域中被称为one-directional。从演示的情况判断,频率应该在10MHz的数量级上,应用距离<1m,似乎最大可以到2m。
    Oct. 6
    做成盘子状扔进去充电/方向性充电和这个video里面的demo难度估计要低一些,现在很多接触性的充电器(比如电动牙刷,剃须刀)几年前就已经实现了这种功能。这个video展示的是真正的无线充电,是有一定的距离的而且omni-directional。this is what makes it new and impressive. But then again, I am really doubtful if staying in a house full of magnetic field used for wireless charging is harmless....wouldn't that burn your brain?...somehow...
    Oct. 6
    Yan Liwrote:
    有次去qualcom visit的时候,他们show的其中一个正在研发的product就是wireless charger,不过跟这个vedio里的原理不同啦,是跟下面yang同学说的差不多的。他们有演示做成的成品,盘子一样,然后手机扔进去就开始充电,还有做成放在桌子下面的,手机扔到桌子上就开始充电,看着还挺有意思的。好像当时是在努力通过safety的要求。。。现在通过没有。。。不知道了。
    Oct. 5
    终于发现有人讨论偶们track的问题了,呵呵~
    Oct. 5
    yangwrote:
    Our lab initiated research on wireless power transfer about two years ago...
    Trying to use different antennas to substitute the coil inside the video.
    Quite interesting but there are a lot issues, distance is one of them.
    Also safety is another concern.
    Oct. 5
    use wireless to transfer power? oo
    Oct. 5
    Jun Zhangwrote:
    yes, it's amazing. I heard about it before, but didn't expect it works so well as in this demo. Seems lots of companies are interested in this.
    Oct. 5
    very impressive...if this is really as safe as he claims and comes at reasonable size/efficiency, this thing is going to be HUGE...
    i am still a bit suspicious about the safety though...let's see how things roll out...
    Oct. 5

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