The term “Internet of Things” (IoT) is currently used to refer to anything, including all commercial and industrial gadgets, condition-monitoring systems for preventive maintenance, and smart, self-powered labels for asset tracking. The purpose of this blog is to assist readers understand how a power-centric mindset may be used at different levels to achieve hierarchical solutions by focusing on the power viewpoint of IoT and identifying terminology and application options.
Numerous objects might be referred to as the Internet of Things (IoT). Some believe it refers to Bluetooth low energy (BLE)-capable gadgets that let smartphones converse with and even command any contemporary electronic device in view. Others believe that the Internet of Things (IoT) refers to the widespread deployment of sensors on everything from high-value assets for tracking to conditional monitoring on equipment for preventative maintenance (better known as the Industrial IoT or (IIoT) to medical wearables and implantables, sending data to the cloud for intensive processing and the creation of data analytics.
The famous 2006 statement by British mathematician Clive Humby, “Data is the new oil,” implies the enormous amount of data analytics and the industries centered on them. Even if it is unclear exactly what that means for the technology of today and tomorrow, it’s possible that for many people, the Internet of Things just means labeling everything “smart,” from toasters to window shades.
Putting Power in Perspective
Specifically in non-tethered applications like remote monitoring, electric/autonomous vehicles (EV/AVs), aerospace/MIL applications, and other ground-based massive transportation, the IoT refers to several battery-based and low-power technologies as well as the aggregation of systems (i.e., railway). From a power perspective, it may refer to widespread deployments of wireless sensor networks (WSN) integrated into settings that are difficult, expensive, or even dangerous to access (i.e., deep oil wells, permanently embedded in structures, wind generator turbine blades).
Additionally, it provides chances for telemetry, control, and preventative maintenance on a scale never before possible. The IoT/IIoT can be essential in both low-power and high-power deployments, even if the circuits themselves are generally low power in nature, as these diverse lists of systems and applications suggest.
The majority of “things” in the IoT are low-power devices that are often powered by batteries. Primarily, these are powered by primary or non-rechargeable batteries. In the near future, it’s predicted that there will be hundreds of billions (if not more than one trillion) of end devices. If we continue to discard more than 100 M batteries daily, this would result in a worldwide tragedy in terms of hazardous waste in landfills.
In addition to these serious environmental or sustainability concerns, this is typically bad business in a purely financial sense because, even if all of those small primary batteries are very inexpensive in high volumes, the cost may end up being many times greater than the entire system if they ever need to be replaced (e.g., operating and maintenance expenses can heavily dwarf capital expenses to dominate the total cost of ownership).
The value proposition for using secondary or rechargeable batteries (or other energy storage devices, such as capacitors) along with scavenging ambient energy, also known as energy harvesting, is elevated by this environmental dilemma and the extremely low system power budgets of many of these devices. The majority of the so-called Power IoT ecosystem consists of this convergence of IoT/IIoT, energy harvesting, energy storage, and low-power connectivity.
Advanced Power Management (IPM)
Most IoT/IIoT applications prioritize maximizing battery life, which is related to the link between available power (such as the energy source) and the system power budget (e.g., the loads). The majority of engineering resources and efforts tend to go toward increasing the amount of power that is available and improving the efficiency of power converters, with far less attention going toward lowering the system power budget.
This can be confusing because there are more chances to use intelligent power management (IPM) approaches to reduce system load consumption than there are to deploy a larger battery or a more effective power converter. In other words, the system power budget will be reduced by Moore’s Law far more quickly than battery energy density would rise. In contrast to integrated circuits (ICs) and even microelectromechanical systems (MEMS) sensors, which may reduce power consumption by almost half while maintaining functionality, battery capacity typically only doubles every ten years or so.
Creating Future Power Supply Designs
Finding the appropriate balance between transmission and sleep time can have a significant impact on battery life because radios are often the main power consumers in an IoT/IIoT device system. Do you need to know that information at that degree of granularity, even if your temperature sensor is capable of sampling at 1 kHz? And maybe more importantly, is processing and transmitting that much data really necessary?
Size, weight, and power (also known as SWaP factors) issues are becoming more prevalent due to the growing trend of integrating computation, sensors, radios, displays, motor control, energy storage, and power management. Disaggregated systems have historically been joined to create increasingly sophisticated integrated components, like System-on-Chip (SoC) or integrated motor drive system loads.
The mention of the growing SWaP factor issues and the concomitant lowering of individual system components may give the impression that the messaging is somewhat contradictory. Since system designers and integrators frequently cram in as many loads and features as they can fit and afford, this is not nearly the dichotomy it may appear to be on the surface.
Therefore, the overall system power budget has a propensity to expand even when individual load footprints have a tendency to reduce their thermal design power (TDP) budgets. The application of IPM approaches, as mentioned above, is where the power electronics and embedded engineering resources come into play in an effort to reduce the system power budget.
Using Less Energy and Providing More Energy
It may seem like a sin to any power supply designer to prioritize power commutation optimization and energy efficiency, but there are some situations where getting power to the load as quickly as possible is the most important thing. For instance, an unforeseen power interruption might have negative effects on industrial automation. This argument can also be particularly clear in applications that run in hard, somewhat inaccessible areas and/or require very little power. Examples of this include WSNs incorporated into huge constructions like bridges or skyscrapers or medical implants or gadgets.
In recent years, wireless power transfer (WPT) has attracted a lot of attention, sometimes as a convenience for consumers and other times as a solution to the problems associated with energy delivery. One distinction that must be made is that many WPT applications are mistakenly categorized as energy harvesting methods. WPT often requires the commutation of power from a directed (typically off-line or wall source), where one of the “wires” just so happens to be a wireless link. However, this may merely be a semantic dispute. This is in contrast to actual, ambient RF (far-field radio frequency) energy scavenging.
In terms of energy efficiency, WPT is equal to utilizing a wired, ac-dc adaptor (also known as the infamous wall wart) from more than 20 years ago for the majority of consumer applications because one cannot make the minimal effort necessary to plug in a wire. On the other hand, despite the inefficiency of the power commutation, WPT can make a lot of sense if one wishes to capture, process, or read data from an IoT node embedded in a solid piece of concrete or supply energy for an in-situ WSN embedded in live tissue.
High Isolation Can Be Needed Even With Low Power
It should not be assumed that a system or Internet of Things (IoT) device is operating in a separated/safety extra-low voltage (SELV) environment, even if it consumes very little power and uses low voltages. Particularly in IIoT applications, the WSN or IoT node may be connected to a sizable piece of equipment or a high-power system that operates off of and/or employs three-phase voltages, necessitating low-wattage power supplies capable of operating from high AC input voltages.
Therefore, it may be necessary for power solutions to support a wide range of input voltages, to offer many kVs of isolation, and to include a variety of protection features, including overvoltage protection (OVP), overcurrent protection (OCP), and overtemperature protection (OTP), among other protection modes. Again, even if the power solution only generates a little amount of power in the 1s or low 10s of watts, all these design requirements may still need to be built into the system. This is crucial for applications like medical imaging and gadgets that directly interact with people.
Sustainability Today and Tomorrow
As previously mentioned, the IoT/IIoT can offer previously unheard-of opportunities for reducing carbon footprint and capital/operations expenditures (CAPEX/OPEX) through the use of massive data analytics, optimizing consumption, and preventative maintenance via conditional monitoring, among other things. The IoT/IIoT can produce unprecedented waste in terms of dangerous materials like batteries and can also use more rare earth elements, finite gases, and valuable metals than the world can support.
One of the most intriguing and potential synergistic relationships in these sectors is the compatibility of IoT/IIoT technologies with energy harvesting since the ideal situation is a sensor system that is permanently self-powered from the ambient environment. This will not only reduce the need for reliability-critical components like primary batteries and connectors, but it will also make it possible to install “forever” systems that don’t require maintenance.
The main lesson is that there are no absolute, straightforward solutions to problems or the related business and pay-back calculations, which is true of most complex problems in life. If one wants to simultaneously maximize performance and sustainability, several second-order considerations must be taken into account.