Background and Motivation

Wireless Power Transfer (WPT) is an increasingly common solution across applications ranging from electric vehicle charging and industrial automation to autonomous mobile robots and medical implants. Among available WPT technologies, Inductive Power Transfer (IPT) is the most widely adopted, and within an IPT system the magnetic coupler most directly drives efficiency, spatial robustness, weight, and cost. Conventional coupler design relies heavily on Finite-Element Analysis (FEA), which, despite its accuracy, is too computationally expensive for the broad parametric sweeps and population-based searches required in early design.

Objectives and Methods

This paper presents a modular MATLAB toolchain, developed at INESC TEC, that provides fast, analytically grounded, manufacturable initial designs for inductive WPT couplers, narrowing the design space before higher-fidelity tools are invoked. Every coil - single-layer, multi-layer, Double-D, or hybrid - is reduced to one unified geometric representation (an array of current-carrying segments), over which five integrated modules operate: Litz-wire dimensioning; coil electrical-parameter analysis (DC/AC resistance, self-inductance, quality factor); spatial coupling analysis across a discretised 3-D misalignment volume; particle-swarm coupling optimisation under user-defined geometric and electrical constraints; and one-factor-at-a-time sensitivity analysis. All coupling metrics rest on a compensation-agnostic figure of merit, independent of the reactive compensation topology chosen downstream.

Validation

The toolchain's air-core electromagnetic model was validated against Ansys Maxwell 2025 R2 across ten coil-pair families, 36 Tx/Rx coupling pairs, and four Litz-wire constructions, at DC and three AC frequencies bracketing the SAE J2954 operating band. Deduplicating repeated evidence units, median errors were 0.5% (self-inductance), 2.5% (total resistance), and 5.4% (mutual inductance), all within standard engineering pass tolerances for a pre-design filter.

Results and Conclusions

The toolchain forms the first stage of a broader five-stage pipeline - FEA air-core cross-check, ferrite/shielding design and integration, electrical assessment, and thermal simulation - carrying candidate couplers through to physical prototypes. Two coupler geometries built and measured at INESC TEC agreed with Maxwell within 4-10% and under 0.8 percentage points of efficiency error, confirming the toolchain's suitability as a reliable, validated pre-design filter rather than a substitute for FEA. By integrating wire sizing, electromagnetic modelling, misalignment analysis, and optimisation in one environment, the tool offers a practical first-pass design aid that avoids the cost of FEA during the early exploratory design phase. This methodology is currently being extended to a full system-level, autonomous robotic-platform WPT prototype under development at INESC TEC.