Structured Innovation: Improving Quality of Wireless Power Transfer
. . . Continuing the series on Structured Innovation . . .
Since the time MEC members first heard about TRIZ some fourteen months ago, seek they had wanted to hear of its application at a well-known organization, prostate especially since they knew that Henrietta and her group had consulted at some of them. However, check considering how its application could lead to innovative solutions and competitive advantage, many of these developments were proprietary.
Fortunately this month Henrietta was able to bring along one of her colleagues, David, who had worked on a project at Intel Labs that he was able to share. Hearing this created a happy buzz amongst the MEC members.
David started by asking, “Have you ever wished that your mobile devices could stay charged forever?”
A rhetorical question, perhaps, but it got everyone nodding, in addition to some comments:
- My electric toothbrush does not need to be plugged in; I just seat it in a pedestal
- I just purchased a charging mat where I simply place my phone on the mat and it charges without the need to plug it in
“Exactly,” said David. “By the same token, I have wished that phone would charge itself without the need for a mat. And I am sure many of you have thought about solar cell phone covers.
The good news is that many companies have been thinking along those lines and trying to come up with a way that these mobile devices could charge by themselves.”
Belinda, the ever-energetic MEC facilitator, piped in, “So here is the ‘itself’ principle that Henrietta mentions quite often.”
Acknowledging, David continued, “We cannot have the phone behave like the iRobot Roomba, the self operating vacuum cleaner, and slide over to its charging station. We are not always at home! And when traveling we do not necessarily want to lug the charger with us. So could there be a way that the phone draws power from somewhere and charges itself?”
Chris, the engineer who had been listening intently, said, “You mean something like wireless power transmission, the challenge that folks have been working on forever?”
“Exactly,” said David, “but on a smaller scale. Fortunately, the largest microprocessor, based in Seattle, Washington, had been working on just such a system for mobile phones where the system was designed to charge a mobile device by way of close proximity to an adapted laptop (Fig. 1). More specifically, the initial design had the transmitted power emanating from the side of the laptop and received through the side of the cell phone (Fig 1a). The system worked well over very short distances, e.g. cell phone placed right next to the laptop. However, even the distance shown in Fig 1a could be problematic. The desire was to expand the effective range of the system.
As you all know by now, the most important step is in understanding the problem and stating it clearly. So, as we got talking to the design engineers, we learned that:
- The phone needed to be placed beside and very close to the adapted laptop
- If placed incorrectly, the power transfer would be substantially reduced.
Before we could begin ap
plying any of the TRIZ principles, we needed to know more about how this wireless power transfer occurred, and the engineers explained it to us by showing us this diagram (Fig 2)
They explained that Wireless Power Transmission works via basic electromagnetism; it creates an electromagnetic wireless activity field by passing current through a transmitter loop (primary coil). The field then passes through a receiver loop (secondary coil) and creates secondary current that is then used to charge the battery. What happens is that as the distance between the Primary Coil and the Secondary Coil increases, the power transfer gets poorer. The challenge, as you recall, was to increase the effective range of the system, i.e., reduce deterioration of the wireless activity over a larger distance between the two coils.
We started by creating a Functional Model of the system. Henrietta here tells me that you have done functional analysis in a couple of the previous meetings. To help us, the engineers drew a more detailed schematic for us (Fig 2a). It helped us see the actual system, its components and their relationship, before we could proceed to the Functional Diagram.
Fig 3 shows the Functional Diagram we ended up with. It is rather complex but bottom line, we found four insufficient functions. This became more evident as we analyzed the functional diagram and four specific areas. In summary, the existing system was not capable of transmitting power over very long distances; thus the emission and absorption of the electromagnetic field was insufficient.”
Chris, ever the engineer piped up again, “ What about the production of EMF and Current 3 that are also indicated as insufficient?”
“We essentially ignored these issues as the first insufficiency could be rectified by simply increasing the power source and the second insufficiency could be rectified when the power transmission was improved. Now that we understood the problem, we needed to reformulate it as a generic TRIZ problem.”
“David, I suspect that the emission and absorption are dependent on the size of the coils.” Chris interjected.
“Yes, Chris,” David continued, “you are absolutely right. The design parameters for an effective wireless power system for our purpose were the shape, size and orientation of the transmission and the receiver coils. Sorry for the technobabble for some of you, but large round coils, around 30 centimeters in diameter, with their faces positioned parallel to each other can transmit and receive electro-magnetic power up to several meters. And a system can work over greater distances if the coils are even larger. So, size is one of the key factors. And you can appreciate why size is a limiting factor when we think of laptop computers and mobile devices, especially with the initial design of having the coils in the sides of the transmitting and receiving devices. With ever shrinking shapes & size of mobile devices, especially where Intel wanted the coils, it is fairly clear why the effective range of the power transmission was limited to a couple of inches. This now allowed us to restate the problem as a general TRIZ problem by defining contradictions:
- The coils need to be large – in order to transmit and receive over long distances (as a result the transmitting device (laptop) and the receiving device (cell phone) would also need to be large because of the large size of the coils)
- The coils need to be small – in order to fit the small form factor (of the transmitting and the receiving devices)”
It was Josh this time, “So we see a physical contradiction here. The coils need to be both large and small at the same time! And as I am sure we all recall, Physical Contradictions are addressed by several methods with some of them being:
- Separation of contradictory properties in time
- Separation of contradictory properties in space
- Separation between the whole system and its parts (but letting the contradictions co-exist)
- Separation based on different conditions; solve in sub-system or super-system”
David turned to Henrietta, “I am impressed with this group,” and then to Josh, “You are absolutely right.
The team developed a few different solutions, so lets review a few that I am at liberty to discuss.
First, and certainly the most simple, is to use flip up and/or fold out coils that can be expanded (not unlike a telescopic antenna) when power transmission is necessary. This uses the first principle of Separation in Time. The coils are small when not in use and they are large when in use. It keeps the system’s form factor small during battery operation and allows for effective power transfer during charging states.
Other solutions required a different level of thinking. What we are trying to do is to improve interaction between the system components. For interaction type problems, TRIZ suggests Su-Field (Substance-Field) modeling and Standard Inventive Solutions (SIS). Henrietta tells me that this is not a topic that she has covered with you yet.
We had already looked at a Functional Model and identified current and electromagnetic field as insufficient components. We thus had identified all the material and the field components. Due to time constraints of today’s session, I cannot really cover the Su-Field methodology in this session; so let me simply share with you some of the concepts considered:
- We developed the Su-Field problem model with a focus on the Zone of Conflict.
- Identified the Standard Inventive Solution to be used in the solution concept generation process: identify solution, refine solution, and make solution more ideal.
Su-Field efficiency could be improved by:
- Tool fragmentation – increasing number of coils along all edges of laptop and lid (screen) (Fig 4a)
- Substance Structure Transformation – transition from substances having non-arranged structure to substances with arranged spatial-temporal structure (perma
nent or temporal) – transfer the coils to the laptop case and hang the phone on the back of the screen when the lid is open (Fig 4b) or create a phone sleeve/case that can perform multiple functions such as receiver antenna, phone stand, repeater, all allowing that device to provide more flexibility in laptop/phone positioning (Fig 4c) - Creating virtual transmission and receiver “loops” – where one would use the laptop and phone to create an ionized loop of air around them and utilize these temporary antennas as the large elements needed for increased transmission distance
As you can imagine, there were those who said the virtual loops would be impossible, but I have learned over the years that naysayers are valuable to the innovation process as they often identify the next level of contradiction to be solved. This is just a snippet of how TRIZ tools are being used by larger organizations to solve some of their complex problems to come up with innovative solutions.
Other considerations included Synchronization/Anti-synchronization of Field-Substance Frequencies, Field structure transformation, Transition to capillary-Porous Materials, Transition to complex Field Models, etc.
Belinda is giving me the sign that we are running short of time; so let me first thank the microprocessor manufacturer for allowing me to share this application of TRIZ in their development process. And, if you have any questions, I will hang around for a few minutes and will try to answer them within the constraints of our non-disclosure agreement.”
Do you have any case studies you’d like to share?
Would you like to learn about inventive solutions?