IIoT project Wireless Power Transfer: Getting rid of cables - in industry, too

The terms Internet of Things (IoT) and Industrial Internet of Things (IIoT) cover a wide variety of technical developments ranging from fitness trackers and agricultural robots to smart factories in an Industry 4.0 scenario. Their common feature is networking while having one goal: to build more flexible solutions via intelligent, decentralized functions.

When hearing about flexible and intelligent solutions, I immediately think of mobile devices that control themselves. But the challenges are: How can devices be made both mobile and autonomous? How can power be supplied to autonomous devices, and how can they communicate and provide feedback? In all cases, I have to let them "off the leash" - they have to be cable-free. No cable for data nor for power - which is not always easy.

Würth Elektronik has proven strengths to “Cut the cord”. The important enabler is Wireless Power Transfer (WPT). We have one of the largest ranges of WPT coils on the market and make it easy for developers to come up with solutions. We demonstrate here how to “Cut the cable.” The main challenge is that the wireless power is very popular and necessary in consumer electronics, the protocols for the WPC Qi standard are not applicable for many industrial applications. The background: The main concern of wireless power standards such as Qi is interoperability, which is intended to make universal charging stations possible for your mobile device. However, those who develop industrial solutions usually have other priorities - primarily, significantly higher power than is provided for in the Qi standard, for example.

However, there are solutions for this as well: Würth Elektronik offers a wireless power development system for applications up to 200 W. Due to the power class, an inductive approach with a resonant converter is recommended for 200 W. The advantage is high efficiency and good shielding of the magnetic field. When designing the application, the distance between the coils must be considered to minimize losses in efficiency. The good news about the solution proposed by Würth Elektronik for applications up to 200 W is that a resonant converter can achieve an efficiency of more than 90 %. This webinar will show the step by step process to realize a WPT solution based on the Wireless Power 200 W Development Kit 760308EMP. The development of a drone as an example will be presented.

Communication by modulation

Say the requirement is to develop a device for use in a clean hygienic application, or in an dirty or wet environment - the device must be sealed, encapsulated, to keep it clean and free of dirt or moisture ingress. Those requirements means the device must be powered by wireless power technology, and of course communication must also be wireless. In many cases, it is sufficient for a mobile device to receive simple commands and simply report a few sensor data readings or its battery status back to a base station. For such cases, our WPT development kit offers a nice lean solution: during wireless power transmission, the device and charging station exchange data via amplitude and frequency modulation. We provide the software for this newly developed wireless solution including a checksum control for free.

As an optional hardware extension of the developer kit, there is also a display board 760308EMPLCD that can, for example, display the temperature from a sensor device, that is powered by WPT and that transmits the data via the ASK modulation. As described in the webinar, the next step, the transmission of data from the base station to a smartphone app, for example, can also be implemented very easily with wireless modules from Würth Elektronik.

Hobby Plane with Wireless Power Charging

Communication via NFC

The headline says IIoT. However, contrary to the terminology, data transmission between machines does not necessarily have to take place via the Internet protocol. If only a small amount of data needs to be transmitted only periodically or a status report only needs to be transmitted occasionally, the integration of a Wi-Fi interface, for example, may be excessive. With the modulation of the WPT for data transmission that will be presented, up to 500 bit/s can be achieved.

Another possibility is the use of WPT for power transfer combined with NFC antenna for data communication. Würth Elektronik offers ‘combination coils’, WPT coil with NFC antenna, that can be tested for your application with the help of the development kit. With a data rate of 848 kBit/s, NFC (Near Field Communication) is actually an RFID standard, but it is used for much more than authentication solutions.

The Application Note ANP084: Impedance Matching for Near Field Communication Applications is recommended on this topic.

Summary

Cutting the power cord also opens up possibilities for wireless data transmission - with the Wireless Power 200 W Development Kit, you can quickly check the feasibility of such ideas. And you should not be misled by the term ‘Internet of Things’. Not every communication needs Internet protocol and Wi-Fi. On the contrary, lean solutions such as amplitude and frequency modulation or NFC are often sufficient. When it comes to larger data volumes, developers should also evaluate proprietary solutions, especially in the industrial sector because depending on the priorities, this often leads to optimized solutions that are superior to the Internet Protocol.