The proliferation of electric vehicles (EVs) as alternatives to combustion engine vehicles has driven advancements in charging technology. Wireless power transfer (WPT) has emerged as a promising charging solution, offering greater convenience than conventional conductive charging methods (Madaram et al., 2024). WPT is becoming popular for charging electromobility fleets (Li et al., 2022) and provides advantages including user convenience through cable elimination, enhanced safety via galvanic isolation, and improved aesthetics (Mukherjee et al., 2021). Wireless charging enables automatic charging for autonomous vehicles and robotic applications, thereby reducing the need for human intervention. EV adoption is driven by government incentives and environmental concerns, resulting in an increased demand for advanced charging infrastructure (Iannuzzi and Franzese, 2020). The transition to wireless charging systems presents challenges in terms of efficiency, electromagnetic interference, safety, and cost. Improvements in power electronics, coil design, and control algorithms are needed for efficiency. Electromagnetic compatibility must prevent interference with other devices. Safety standards are crucial for protecting users of high-power wireless charging systems. Standardisation and interoperability are essential for seamless EV charging across stations (Sh et al., 2024). Addressing these challenges will enable the widespread adoption of wireless EV charging for sustainable transportation.

Despite advancements, the efficiency of high-power WPT systems for EV charging at 5 kW remains suboptimal due to coil misalignment, magnetic leakage, and losses in power electronic components. Misalignment reduces magnetic coupling efficiency, causing magnetic leakage that prevents effective energy transfer. This study aims to develop a 5 kW IPT system optimised for improved power transfer efficiency and reliability in electromobility applications. Wireless charging faces challenges that require efficient and reliable operations. Coil design must optimise geometry, materials, and winding configuration to maximise magnetic field strength while minimising losses (Acharige et al., 2023). The coupling coefficient between transmitting and receiving coils must be maximised for efficient power transfer (Singh et al., 2022). Misalignment can significantly reduce the coupling coefficient and transfer efficiency (Afshar et al., 2020). Electromagnetic compatibility remains a concern (Aibinu et al., 2021). Addressing these challenges requires optimising coil design, coupling coefficient, and misalignment effects. Advanced control techniques can enhance efficiency and stability. A multidisciplinary approach involving electromagnetics, power electronics, and control systems is needed, considering the interplay between design elements and system integration. Electromagnetic interference mitigation through shielding is essential for compatibility. Safety is paramount in WPT, requiring protection mechanisms against overvoltage, overcurrent, and overtemperature hazards. Through innovative designs, control techniques, and safety measures, high-performance 5 kW wireless charging systems can meet the growing demand for efficient EV charging. The 5 kW system suits residential use due to power supply constraints, as current systems either exceed residential capabilities or fail to meet daily EV charging needs (Roslan et al., 2021).

The adoption of electromobility is transforming transportation, driven by the need to reduce greenhouse gas emissions and improve energy efficiency (Deilami and Muyeen, 2020). However, the limited range and long charging times of EVs remain obstacles to widespread adoption (Safayatullah et al., 2022). Wireless charging technologies provide convenient alternatives to traditional plug-in charging methods, enabling automatic charging in parking spaces and on roadways (Dimitriadou et al., 2023). This technology also enables wireless charging of smartphones, laptops, and wearable devices without the need for physical connectors (Seth and Singh, 2021). Electromobility adoption has expanded rapidly over the last decade as the global energy sector shifts away from fossil fuels (Abro et al., 2023). Lower battery costs, government policies, and consumer demand have driven this growth. As EV adoption increases, accessible charging infrastructure becomes critical, leading to research on optimising charging station placement and algorithms (Xiao et al., 2022). A 5 kW wireless charging system is justified due to its balance of power, efficiency, and applicability across various scenarios. These systems are suitable for residential charging and can be easily integrated into power grids (ElGhanam et al., 2021). The 5 kW charging rate adequately meets daily EV charging needs, providing an efficient solution. 5 kW wireless charging systems are ideal for small electromobility fleets, such as scooters, motorcycles, and neighbourhood electromobility. They offer compact, cost-effective solutions for urban and low-range mobility applications. These systems can be scaled to higher power levels by using multiple charging pads or increasing the power-transfer capability. This scalability makes them suitable for both residential and public charging infrastructure. Given their grid compatibility, suitability for small EVs, and scalability, 5 kW wireless charging systems represent a promising solution for advancing wireless charging technology and sustainable transport.

Integrating electromobility into an energy system necessitates careful consideration of charging infrastructure and its impact on the grid (Al-Ogaili et al., 2020). Electromobilities can charge and discharge anywhere in the distribution grid. Uncoordinated charging can lead to voltage variations and reduced power quality (Ayoade and Longe, 2025a). Smart charging strategies can improve grid stability (Alexeenko and Bitar, 2023). Vehicle-to-grid (V2G) technology allows EVs to discharge electricity back into the grid, mitigating load fluctuations (He et al., 2020). The increasing EV adoption implies a higher grid load, with charging behaviour affecting demand patterns. Smart charging can optimise this demand within the grid capacity (Mastoi et al., 2022). The grid benefits from storage components by selling electricity during peak hours, improving rotational capacity and frequency regulation (Nour et al., 2020). Wireless charging technologies offer promising alternatives to plug-in charging due to their convenience, safety, and potential for integration with autonomous systems (Ayoade and Longe, 2025b). However, coil misalignment, magnetic leakage, and converter losses limit the efficiency of high-power IPT systems (Ayoade et al., 2024; Biswas et al., 2025). Prior studies have improved compensation topologies (Bons et al., 2021; Jin et al., 2021), coil geometries (Sohet et al., 2020; Xu and Huang, 2020), and controls (Yumiki et al., 2022); however, the efficiency of 5 kW-class systems remains suboptimal under real-world conditions. This study also addresses these challenges by developing and validating a 5 kW high-frequency.

Building on the identified research gaps in efficiency, misalignment tolerance, and electromagnetic compliance, this study makes several key contributions to advancing high-power wireless EV charging technologies. The uniqueness of this study lies in its integrated design framework, which combines high-frequency resonant compensation, electromagnetic safety compliance, and adaptive control into a single 5 kW IPT platform optimised for EV wireless charging. Unlike conventional IPT designs that prioritise power transfer alone, the proposed system introduces a multi-constraint optimisation of coil geometry, compensation network, and converter topology to achieve both high efficiency (92.5%) and misalignment tolerance (up to ±60 mm) without additional mechanical alignment or complex feedback circuits. The system’s dual-side controlled CC–CV regulation provides seamless battery charging stability, extending the constant-current region by 17% compared with traditional primary-side-only control strategies, a capability consistent with recent high-efficiency topologies reported in (Li et al., 2024; Wang et al., 2025). In addition, the proposed architecture innovatively applies a Hammerstein-model-based controller to stabilise the inverter phase-shift operation under coupling variations, an approach not widely implemented in 5 kW-class IPT systems. This control technique ensures ZVS retention and mitigates harmonic distortion, yielding a THD of <6.3% compared to ≥15% in prior SS-compensated prototypes. The magnetic-field mapping of the design validated compliance with the ICNIRP (27 µT limit), ensuring electromagnetic safety, which is often overlooked in earlier studies. The integration of experimental field compliance with analytical modelling represents a holistic advancement aligned with contemporary standards, such as SAE J2954.

This work contributes an integrated framework for a 5 kW IPT system combining resonant design, misalignment-aware modelling, soft-switching control, harmonic mitigation, and CC–CV battery charging within a validated platform. The study links performance to variations in mutual inductance, quantifies the mechanisms of misalignment loss, verifies electromagnetic safety compliance, and demonstrates strong agreement (<3% deviation) between simulated and experimental results. These contributions provide a robust wireless charging solution that advances EV IPT research. The system employs an 85 kHz series–parallel compensation topology, with integrated design features not previously presented in existing IPT literature. The study validates an efficiency hypothesis predicting power transfer dependence on coupling coefficient and mutual inductance under variations in air gap and lateral misalignment. The system utilises hybrid coil geometry, combining a racetrack transmitter and a circular receiver coil to enhance lateral field uniformity without the need for additional coupling pads. The converter features ZVS phase-shift modulation on the primary side and CC–CV regulation on the secondary side, enabling <1.5% ripple and stable charging. The study presents a loss decomposition analysis of the effects of misalignment on copper losses, inverter switching losses, rectifier losses, and magnetic leakage. Electromagnetic field measurements verify ICNIRP compliance under nominal and misaligned conditions, establishing a novel IPT platform that advances both analytical understanding and practical reliability of 5 kW wireless EV charging.

Recent high-power IPT systems at 3.3–10 kW typically operate at 85 kHz with efficiencies of approximately 88%–91% and varying misalignment tolerances, for example, 3.3 kW circular designs at 20 kHz (≈88%) and 6.6–7 kW at 85 kHz (≈90–91%) with only moderate lateral offsets maintained under test. This study achieves comparable or better performance at 5 kW while adding safety-verified leakage control, quantified loss auditing, and battery-aware CC–CV integration, which many benchmarks do not report in a unified study. The significant contributions of this study are as follows.

The high efficiency at 5 kW with a complete charging chain evaluated, and the system achieved a peak simulated dc-dc efficiency of 92.5% and an experimental wall-to-battery efficiency of 86.7% at 85 kHz with a 72 V pack, positioning it within or above the range reported for 3.3–7 kW systems while explicitly measuring end-to-end loss. Numerous recent studies on misalignment-focused couplers omit the dc-dc efficiency; however, this study reports it and audits the sources of loss.

Having established these contributions, the remainder of this article is structured as follows: Section 3 presents the system modelling, the design methodology and the experimental setup and validation procedures, Section 4 discusses the results and comparative analysis, and Section 5 concludes with key findings and future research directions.

The simulation model, as shown in Figure 2, represents a 5 kW high-frequency IPT system for EV charging, developed using MATLAB Simulink (2025a). The system began with a 220 V RMS, 50 Hz AC grid source, which was rectified using a diode bridge to produce a stable DC voltage. This DC is filtered using an LC circuit and fed into a high-frequency inverter operating at 85 kHz, which converts it into a high-frequency AC signal, required for efficient WPT. The primary compensation network includes a series capacitor ( C 1 ) designed to resonate with the transmitter coil at the operating frequency, enhancing power transfer efficiency. The transmitter and receiver coils, each with 25 turns and separated by an air gap of 100 mm, formed a magnetic coupling interface for power transmission. On the secondary side, the receiver coil was tuned using a series capacitor ( C 2 ) to maintain resonance and transfer the maximum power to the rectifier circuit. The AC power was converted back into DC using a full-bridge vehicle rectifier, which supplied a 72 V lithium-ion battery. The simulation included real-time monitoring of high-frequency currents on both sides, DC link voltage, battery input power, and the battery SOC tracked using voltage and current feedback. A constant-current control strategy was implemented via a current sensor feedback loop to maintain stable battery charging and protect against overcurrent events. The system evaluates the input active and reactive powers, DC link behaviour, and battery charging dynamics under both nominal and transient conditions, providing a comprehensive and realistic assessment of WPT performance. The resonant frequency was designed at 85 kHz, but measurements showed actual resonance at 84.8 kHz, a 0.24% detuning due to component tolerances and parasitic effects.

The measured resonance shift from 85 kHz to 84.8 kHz represents a 0.24% detuning, and this deviation did not impact performance, as the inverter maintained a ±7 kHz soft-switching window around resonance. Oscilloscope measurements confirmed consistent zero-voltage switching under varying loads. The SS compensation topology’s flat voltage gain characteristic near resonance resulted in a variation of less than 1.5% in the output voltage. These results demonstrate the IPT system’s robustness against variations in component tolerances and load.

The plot in Figure 3 shows that the power transfer efficiency decreased exponentially as the air gap increased. This is owing to the reduced mutual inductance and weaker magnetic coupling at larger separations, highlighting the critical importance of minimising the air gap in the IPT system design for optimal performance. The Simulink result in Figure 4 demonstrates stable 85 kHz operation with minimal voltage/current distortion, achieving an efficiency greater than 90%. Source measurements showed proper inverter synchronisation, with a minor phase shift of 5° owing to the LCL network reactance. The DC link maintains tight regulation (ripple <0.1% of 48 V), whereas the SiC MOSFET switching and capacitor ESR account for the CC W losses. On the receiver side, the EE V and FF A outputs confirmed a GG% power transfer efficiency, with a slight coil imbalance detectable in the C1/C2 branches. The system meets the dynamic charging requirements but can benefit from adaptive frequency tuning to optimise coupling variations.

The roadside winding voltage in Figure 4 exhibits a stable 85 kHz oscillation with a peak amplitude of 325 V (based on a 48 V DC-link with a 6.8x resonant gain), confirming the proper operation of the resonant converter. The current waveform exhibited near-sinusoidal characteristics with a peak current amplitude of 22 A, although a slight phase lag of 12° relative to the voltage indicated reactive power circulation in the transmitter coil. The current zero-crossings align precisely with the voltage peaks, demonstrating the effective soft-switching operation of the SiC MOSFETs. The Δ20 A current variation during 0.1–0.2 s intervals suggests controlled power modulation for alignment compensation. The harmonic distortion remained below 5%, thereby meeting the IPT standards for EV applications. Figure 5 shows the transmitter-side voltage and current characteristics of the WPT.

The vehicle-side winding voltage in Figure 6 demonstrates rectified sinusoidal characteristics with a peak amplitude of 280 V, indicating proper resonant coupling from the transmitter. The current waveforms exhibited a peak amplitude of 18 A, maintaining a near-unity power factor (phase lag of less than 5°). Voltage-current synchronisation confirmed efficient AC-DC conversion, with a ripple frequency of 170 kHz matching the expected double of the operating frequency of 85 kHz of the full-bridge rectifier. The observed waveform distortion of <3% THD suggests optimal tuning of the receiver-side compensation network. The 92.5% power transfer efficiency, calculated from the V/I product, satisfied the charging requirements.

The battery voltage profile in Figure 7 demonstrates stable charging characteristics, maintaining approximately 400 V DC with less than 1.5% ripple, indicating effective filtering by the vehicle-side power electronics. The current waveform shows a controlled ramp-up to 12.5A, corresponding to a 5 kW power transfer at 400V, with a near-constant current phase beginning at 0.1 s. The 95% current voltage overlaps during constant-current charging confirmed the proper operation of the battery management system (BMS). A minimal voltage fluctuation of ±6 V was observed during the mode transitions, and precise current regulation matched the constant current–constant voltage (CC-CV) charging curve.

The DC-link voltage in Figure 8 maintains stable regulation at 48 V nominal with a peak-to-peak ripple of <2.5%, demonstrating effective capacitor bank performance. Current measurements show a 104 A peak (theoretical: 5 kW/48 V = 104.2 A) with smooth transitions, confirming proper inverter modulation. The 0.9% THD in the current waveform indicates minimal high-frequency noise from the SiC MOSFET switching. The system exhibited voltage regulation of ±1.2 V under full load, current-phase alignment with an inverter switching frequency of 85 kHz, and absence of voltage sag during power transitions. The SOC curve in Figure 9 demonstrates stable charging behaviour, with a gradual increase from 51.6440% to 51.6452% during the 0.3 s simulation window. This corresponds to a 0.0012% SOC gain, reflecting the system’s 5 kW charging capability for a high-capacity 75 kWh EV battery pack. The linear progression indicates (1) proper coulomb counting by the BMS, (2) Absence of SOC estimation drift, and (3) consistent energy transfer matching theoretical calculations (0.0012% SOC ≈0.9 Wh energy transfer).

The voltage waveform in Figure 10 exhibits a controlled transient response, stabilising at 400 V DC after the initial oscillations (±50 V) within 0.04 s. The current (on a 10³ scale) shows the corresponding inrush characteristics, peaking at −30 kA during startup before settling into steady-state operation. This demonstrates the effective performance of the snubber circuit, proper soft-start implementation, and damping of the resonant circuit oscillations. The 0.1 s stabilisation time meets the industry standards for EV charging systems, with a voltage overshoot greater than 1% in the steady state. The wireless charging system exhibits a slower charging rate compared to an equivalent 5 kW wired system, owing to inherent efficiency losses in the magnetic coupling, compensation, and power conversion stages, typically 10%–20% lower efficiency than wired charging at the same rating (Hsieh et al., 2017). This is evident from the gradual increase in SOC, confirming that while wireless systems provide convenience, they trade off the charging speed.

The upper waveform (scale: 0–2000) represents instantaneous power transfer, peaking at 1.8 kW before stabilising to a nominal power of 1.5 kW, reflecting the dynamic power adjustment capability of the system. The lower waveform (scale: 0–60) shows efficiency progression from 85% to 92% during the 0.3 s simulation, the output demonstrates rapid system warm-up of 0–0.05 s, an optimal coupling achievement at 0.1 s with 92% peak efficiency, and a stable operation with less than 1% fluctuation of the efficiency afterwards. The 7% efficiency improvement during operation confirmed proper alignment compensation and resonant tuning. These results validate the system’s ability to maintain a high-efficiency power transfer of greater than 90% and provide a dynamic response to coupling variations, meeting the SAE J2954 performance benchmarks for wireless EV charging.

The results shown in Figure 11 demonstrate robust performance across all critical subsystems of the wireless charging system. The transmitter-side electrical characteristics revealed stable 85 kHz operation with a peak voltage of 325 V and a current of 22 A, exhibiting a minimal 12° phase lag, which confirmed efficient soft-switching operation. On the receiver side, the system maintained a 280 V rectified output with an 18 A charging current, achieving a power transfer efficiency of 92.5% through well-tuned LCL compensation. The DC-link stage achieved excellent voltage regulation of 48 V ± 1.2 V with a current capacity of 104 A, supporting full 5 kW power transfer while maintaining a ripple of less than 2.5%. The battery charging profiles exhibited proper CC-CV characteristics, with the 400 V pack showing only a 1.5% voltage ripple during 12.5 A of constant current charging. The system demonstrated stable thermal performance, with temperatures stabilising at 42 °C (ΔT<15 °C) during continuous operation. SoC monitoring confirmed linear progression (0.0012% SoC gain in 0.3 s simulation), while transient responses met industry standards with a 0.1 s stabilisation time and less than 1% voltage overshoot. These collective results validate the compliance of the design with the SAE J2954 standards (Sulejmani et al., 2023), showing a particular strength in efficiency greater than 90% across all stages, thermal management, and dynamic response characteristics, which are essential for real-world EV charging applications.

This study presents the design, modelling, simulation, and experimental validation of a 5 kW high-frequency IPT system for wireless electromobility charging. The research hypothesis that efficiency and delivered power are primarily determined by the coupling coefficient (k) and mutual inductance (M), which are sensitive to misalignment and air-gap variations, was rigorously validated through analytical modelling and experimental measurements. The developed system achieved a simulated peak efficiency of 92.5% and an experimental wall-to-battery efficiency of 86.7% at nominal alignment, which decreased to 65.3% under a 60 mm lateral offset. Loss analysis revealed that coil copper losses accounted for 6.2% of the total input power at nominal alignment, increasing to 10.5% under misalignment. In contrast, inverter and rectifier losses contributed 4.1% and 3.0%, respectively. The inverter operated with verified zero-voltage switching (ZVS) across an 85–88 kHz frequency window, and the DC link voltage was stably regulated at 310 ± 2 V with less than 1.5% ripple during charging. The battery maintained proper constant-current/constant-voltage (CC–CV) charging characteristics at 70 A, with an overall harmonic distortion of <6.5%, confirming effective soft-switching and harmonic mitigation control. The system sustained its performance across air-gap variations from 10 to 100 mm, validating the robustness of the design relative to the benchmarked 3.7–11 kW systems in the literature. The findings explicitly support the study objectives, demonstrating that high-efficiency wireless EV charging can be achieved through optimal resonant compensation, careful control of coupling parameters, and adaptive inverter modulation. Quantitative comparisons affirm that the proposed IPT system delivers comparable or superior performance to state-of-the-art configurations, achieving >90% efficiency while maintaining safe electromagnetic exposure levels (<27 μT at 10 cm), in accordance with the ICNIRP and SAE J2954 standards.

Future work will focus on the development of adaptive multi-coil architectures and double-LCC compensation networks to further enhance misalignment tolerance and maintain constant efficiency under dynamic operating conditions. The integration of real-time mutual inductance estimation with closed-loop adaptive frequency tuning enables self-optimising resonance tracking to compensate for coil displacement. Moreover, incorporating bidirectional V2G capabilities, AI-based predictive control, and augmented reality (AR)-assisted diagnostics can expand the functionality and scalability of the system for smart grids and autonomous charging ecosystems. Finally, future prototypes will investigate thermal behaviour, EMI suppression, and system miniaturisation through ferrite optimisations and wide-bandgap (SiC/GaN) devices, aiming to develop a compact, high-efficiency, and commercially viable IPT platform for next-generation electromobility.