Printed Electronics Power Supply for IoT Systems

CeNTI - Center for Nanotechnology and Smart Materials is an institute of R&D located in Famalicão. The main goal of the institute is to promote activities of research, Technological Development, Innovation and Engineering with special focus in smart materials and systems. The Internet Of Things is the concept by which multiple devices, are connected and performing activities with each other, such as communication and processing, without human interference. The development of multiple technologies such Artificial Intelligence, Machine Learning, Smart homes, smart devices has accelerated the convergence of all into networks. These networks at the edge of the system possess devices that are meant to make the connection between cyber environments and physical ones. This type of devices are often referred to as Edge devices. Devices like these are most often low power devices used to sense aspects of the physical system and their dimension might be a defining factor to decide if such system is adequate to its function. In sensors the most common forms of power supplies are batteries, mains electricity with a transformer for voltage division and isolation or a combination of both. With the increasing need for miniaturization and technological means to achieve it, the investigation of novel forms becomes more and more relevant. The main objective of this thesis is to investigate the use of printed electronics and in particular printed inductors, to attain an efficient and safe power supply adequate for human handling while aiming to reduce the final volume of the system. The approach intents to use the traditional Transformerless Power Supply circuit configuration using capacitors to drop the mains voltage. Such goal is to prevent undesired power expenditure caused by the introduction of resistances. Besides the voltage drop and rectification the other major concern of the system is the safety of the human operator that may touch the device. Voltage dropping and rectification of grid power is an extremely dangerous circuit configuration due to different ground references and creates an electrocution hazard to both living beings and devices connected to it. The way to circumvent the danger is to introduce galvanic isolation. The system proposed in this project physically separates the output of the system from the input with energy being transferred magnetically. For that purpose, printed inductors are stacked to achieve a planar air-core transformer. The system aims contributes to the continued minimizing of Edge devices that will become progressively more present in everyday life.In recent times, connected devices are becoming increasingly more common. Such devices usually referred to as IoT (Internet of Things), are converging to ever small builds. This document aims to deepen the progress in the field of miniaturization of such devices. To achieve this goal a power supply is designed. The project intents to offer an alternative to common power supplies by making use of printed inductors. Such components intent to replace the traditional transformer by suppling a reduced volume alternative. An investigation into these inductors is conducted and an implementation of its use is presented. The investigation led to conclude that the inductors may be used to provide isolation but further improvements into the fabrication process are required. Due to the current fabrication process involving impure silver as the conductor the resulting coils have a resistance excessively high. This creates difficulties in magnetic field creation as well as introducing a great level of losses. To solve this problem the presented implementation uses high frequency switching to allows for better results in the receiver side of the system

Development of Wireless Charging for Mobile Application using PV Module

In this paper, a wireless power transmission (WPT) using resonant magnetic coupling for mobile phone charger is presented. Solar energy was used as the energy source to address the scarcity of non-renewable energy sources and tackles the constraints of wired charging technology such as lack of universal electrical standard, untidiness and inconvenience of wires and wires' wear and tear. The system includes PV panels and battery, oscillator, transmitting coil and receiving coil and rectifier. Proteus 8.1 was used to simulate before implementing in the hardware. The resonant magnetic coupling resonated at 800 kHz ± 10 kHz. The maximum distance to charge a mobile phone was 4 cm at 3.7 V. All the objectives are achieved within the limited time frame. The significance of the project can help to eradicate the use of wires and the need of power plugs. The future research includes the study of efficiency, coil design, system with multiple loads

HIGH VOLTAGE RESONANT SELF-TRACKING CURRENT-FED CONVERTER

High voltage power supply design presents unique requirements, combining safety, controllability, high performance, and high efficiencies. A new Resonant Self-Tracking Current-Fed Converter (RST-CFC) is investigated as a proof-of-concept of a high voltage power supply particularly for an X-ray system. These systems require fast voltage rise times and low ripple to yield a clear image. The proposed converter implements high-frequency resonance among discrete components and transformer parasitics to achieve high voltage gain, and the self-tracking nature ensures operation at maximum gain while power switches achieve zero-voltage switching across the full load range. This converter exhibits an inherent indefinite short-circuit capability. Theoretical results were obtained through simulations and verified by experimental results through a complete test configuration. Converter topology viability was confirmed through hardware testing and characterization

A Class-E Inductive Powering Link with Backward Data Communications for Implantable Sensor Systems

The design and implementation of a wireless power and data transfer system based on inductive coupling, having the potential to be used in numerous implantable bio-medical sensors and systems, is presented. The system consists of an external (primary) unit and an internal (secondary) unit. The external unit incorporates a high-efficiency switch-mode Class-E amplifier operating at ~200 kHz for driving the primary coil. The secondary unit consists of a parallel resonant coil followed by the power recovery circuitry. Means for backward data communication from the internal to the external unit over the same pair of coils has been realized using a simple FSK-based modulation scheme incorporated into the internal unit. FSK demodulation and associated filtering are integrated with the base inductive powering system. Prototype system test results indicate the inductive link efficiency can exceed 80% under optimum operating conditions with the overall power transfer efficiency of approximately 30%. The communication system is capable of transmitting up to 10kbps of data with the FSK carrier frequency (i.e., middle-frequency) being only 120kHz. The complete system functions reliably over an inter-coil distances exceeding 2.5cm with a 5V dc supply

ASDTIC control and standardized interface circuits applied to buck, parallel and buck-boost dc to dc power converters

Versatile standardized pulse modulation nondissipatively regulated control signal processing circuits were applied to three most commonly used dc to dc power converter configurations: (1) the series switching buck-regulator, (2) the pulse modulated parallel inverter, and (3) the buck-boost converter. The unique control concept and the commonality of control functions for all switching regulators have resulted in improved static and dynamic performance and control circuit standardization. New power-circuit technology was also applied to enhance reliability and to achieve optimum weight and efficiency