Wireless Power Transfer (WPT)

Course 264

Summary

This two day course presents the basics of magnetic coupling and applications to power and data transfer ( Near Field Communication - NFC ). Included topics are, coil and system design techniques, simulation and models, building and testing your prototypes, optimization, experimental characterization and commercial solutions.

Outline:

DAY 1

Fundamentals

Important and basic topics critical to design and/or optimize any WPT system: Why magnetic coupling is useful.- Examples of systems and products with magnetic coupling technology - Near vs far field in electromagnetic waves.- Low and high impedance circuits.- Resistance in DC and AC: skin effect.- Total and partial inductance.- Magnetic coupling and mutual inductance.- Resonance, quality factor and bandwidth.- Broadband versus narrowband applications.- Applying resonance to magnetic field coupling.- Coupling distance.- Voltage, current or power variables.

Applications of magnetic coupling

A very fast review of the wireless coupling applications: Typical diagrams for power and/or data transfer.- Wireless Power transfer (WPT) .- Induction heating . -RFID, Near Field Communications (NFC). Etc..

WPT system architecture

Topologies, block diagrams, and architectures oriented to WPT: WPT standards and global organizations: - Qi charging systems. - TX-RX system architectures and electronic blocks. - Modulation techniques.- Single ended vs differential designs. - The role of buck converter in a WPT system.

Elements for a wireless magnetic coupling system

Components and elements used in the design of any WPT system: Coils (wired and in PCB).- Components for resonance and matching. - Problems in high Q (narrowband loads).- Amplifiers: full bridge v/s half bridge inverters. - Advantages and disadvantages of one over the other.- Components for amplifiers: transistors (FETs) and gate drivers.- Control topics: fixed clock, PWM signal.- Filters and shielding: topologies, commom mode chokes, and ferrites.

DAY 2

Special techniques

Special components and techniques for a successful design: Thinking in efficiency. -Thinking in EMI/EMC.- EMI/EMC reduction techniques for low frequencies: 9KHz-1GHz.- Effect of duty cycle variation.- Effect of rise and fall times in driving signals.- Common mode currents: the effect of a common mode choke.- Mitigation of mismatch in differential designs.- Ferrites- Transient protection

Instrumentation and lab techniques

Tools and techniques to measure and optimize your WPT in the lab: Scopes and time domain . - Spectrum analyzer and frequency domain. - VSWR bridges and tracking generator. - Near field probes. - Escáners. - Tuning strategies.

Design techniques and example

General design process and an example with demos: Qi charging - system design.- Exercise/example: design an entire basic system. - Practical demonstrations.

Target Audience

Engineers interested in WPT and NFC.