Technological Advancements in AC Charger Design

1. Implementation of Silicon Carbide (SiC) Components

Croatia’s electroindustry, led by Končar, has integrated 4th-generation SiC MOSFETs into its eCharg 22 kW systems. These power semiconductors operate at frequencies up to 150 kHz with losses of just 1.8 W/cm²—47% lower than traditional silicon IGBTs. A key innovation lies in the trench-gate design of Rohm’s components, reducing switching time to 15 ns and significantly improving efficiency across load ranges (10–100%).

Data from testing facilities in Samobor show 98.4% efficiency at 32A loads, alongside a 22% reduction in converter weight compared to previous generations. This is critical for urban installations where space constraints demand compact solutions.

1.1 Hybrid Topological Designs for Multi-Purpose Use

Rimac Automobili is developing a dual-active bridge (DAB) configuration that combines AC/DC and DC/DC converters into a unified system. This design enables:

  • Automatic voltage adjustment (200–800V DC) for compatibility with diverse battery packs

  • Intelligent power management between photovoltaic systems and the grid

  • Soft-switching operation across the entire load spectrum

Tests on a 150 kW prototype demonstrate 96.7% overall efficiency even at 15% load, outperforming conventional LLC resonant converters. This technology will be pivotal for future 800V high-voltage systems anticipated in next-gen EVs.

2. Grid Integration Challenges and Solutions

2.1 Dynamic Voltage Stability Management

A study on HEP’s distribution grid in Split revealed critical voltage drops of 6.2% when 12×22 kW AC chargers were activated simultaneously on a 400V busbar. To address this, Končar developed an adaptive DC link controller with:

  • Real-time grid impedance monitoring via frequency response analysis (FRA)

  • Dynamic current limitation in 1A increments

  • Integration with ENTSO-E SCADA systems for predictive management

Deploying this technology at 35 locations along the Adriatic Highway reduced voltage collapse incidents by 72% between 2023–2024.

2.2 Synergy with Distributed Renewable Energy

SoltiQ’s mobile charging system integrates three core elements:

  1. 10 kW bifacial PV modules with 23.7% conversion efficiency

  2. 57.6 kWh LFP battery packs with active cell balancing

  3. Bidirectional 11 kW AC/DC converters with 94.2% round-trip efficiency

Field tests on Vis Island demonstrated the system’s ability to:

  • Provide 18 hours of autonomous operation at 7.4 kW loads

  • Reduce diesel consumption by 62 tonnes of CO₂ annually per station

  • Synchronize with existing diesel generators via modular synchro-clusters

3. Thermal Management and Equipment Longevity

3.1 Advanced Cooling Systems

Graphene-enhanced paraffin waxes in SoltiQ chargers exhibit:

  • Thermal conductivity of 8.7 W/mK (142% better than conventional PCMs)

  • Phase-change latent heat of 218 kJ/kg

  • Stability across 5,000+ thermal cycles

These materials maintain critical component temperatures below 65°C even at 40°C ambient, extending electronics lifespan by 30–35%.

3.2 Battery Health Monitoring

Incremental capacity analysis (ICA) in ULandPower systems enables:

  • Anode degradation detection with 98% accuracy

  • Remaining capacity prediction (±2.3% error)

  • Adaptive charging algorithms based on battery health

4. Regulatory Framework and Economic Considerations

4.1 EU Directives and National Implementation

Under Directive 2024/123/EU, Croatia must ensure by 2026:

  • Minimum 1 AC charger per 60 km of TEN-T network

  • 150 kW total power per 1,000 registered EVs

  • Full interoperability via OCPP 2.0.1 protocol

The Croatian Chamber of Economy’s (HGK) action plan outlines:

  • 22% of funding (€44 million) for rural areas

  • Subsidies covering 40% of private investor costs

  • Mandatory V2G readiness for all new stations

4.2 Cost-Benefit Analysis

A Zagreb Institute of Economics study for 22 kW AC stations shows:

  • Initial investment: €16,450 (excl. VAT)

  • Annual maintenance: €850

  • Revenue per station: €3,200/year (18% average utilization)

  • ROI period: 6–8 years depending on location

5. Case Study: V2G Implementation in Zagreb’s Novi Zagreb District

5.1 Technical Specifications

  • 32×11 kW bidirectional stations (Siemens Sicharge UC)

  • 500 kWh lithium-iron-phosphate (LFP) storage

  • AI management platform (NVIDIA Jetson AGX)

5.2 Results After 12 Months of Operation

  • 14.7% reduction in grid peak loads

  • 63% average station utilization

  • €28,500/year savings in grid maintenance

  • 19% extension in battery lifespan via optimized SoC profiles

6. Future Development Directions

6.1 Material Science Innovations

  • Development of GaN-on-SiC hybrid transistors for 44 kW OBC systems

  • Topological insulators to minimize losses in high-frequency converters

6.2 Smart Grid Algorithms

  • Federated learning for distributed charging management

  • Quantum neural networks for demand forecasting

6.3 Policy and Standardization

  • Dynamic tariff models based on levelized cost of charging (LCOC)

  • Blockchain integration for decarbonization tracking

Leave A Comment