How Transformer Design Supports More Reliable EV Charging Equipment

As electric vehicle charging infrastructure expands, charging equipment manufacturers are paying greater attention to the reliability of internal power-conversion components. While charging systems are often evaluated by charging speed, output power, and communication functions, magnetic components also have an important influence on voltage conversion, electrical isolation, thermal performance, and overall system stability.

For EV charger manufacturers, charging pile developers, and power electronics companies, transformer selection requires more than simply matching a power rating. Parameters such as turns ratio, inductance, leakage inductance, insulation performance, operating temperature, package dimensions, and circuit topology should all be evaluated against the actual converter design.

The EV Charging Transformer from JASN, model PEE4301-001, is a planar transformer developed for EV charging and new-energy power applications. Its published configuration features a full-bridge topology, 1200W power rating, 28:6:6 turns ratio, and DIP package with dimensions of 62 × 45 × 30.1 mm.

Why Transformers Are Important in EV Charging Systems

Providing Electrical Isolation

EV charging equipment operates with significant electrical energy, making controlled isolation between different circuit stages an important design consideration. A transformer can transfer energy between primary and secondary circuits while maintaining galvanic isolation.

The required insulation level depends on the complete charging system, including input voltage, output voltage, working voltage, transient conditions, creepage and clearance requirements, and applicable safety standards.

Supporting High-Frequency Voltage Conversion

Modern power converters commonly use high-frequency switching to improve power density and reduce the size of magnetic components. A transformer designed for the corresponding switching frequency can transfer energy between circuit stages while providing the required voltage relationship.

The PEE4301-001 uses a 28:6:6 turns ratio, providing two secondary winding sections. The actual voltage conversion performance depends on the converter topology, switching frequency, duty cycle, input voltage, rectification method, and control strategy.

Core Parameters of the JASN EV Charging Transformer

These specifications provide a technical reference for engineers evaluating the transformer. Actual performance should be verified under the intended input voltage, switching frequency, load condition, ambient temperature, and converter topology before mass production.

Why Planar Transformer Design Is Relevant to EV Chargers

Supporting Compact Power Electronics

Charging equipment manufacturers are increasingly looking for ways to increase power density while keeping the overall enclosure compact. Traditional magnetic components can occupy substantial space as power requirements increase.

Planar transformer structures provide an alternative approach by using a compact magnetic and winding arrangement that can be integrated into modern PCB-based power systems. This makes them particularly relevant to applications where available installation space is limited.

Improving Integration With PCB Designs

The PEE4301-001 uses a DIP package, allowing it to be integrated into compatible printed circuit board assemblies. Before PCB production, engineers should evaluate component height, pin configuration, creepage and clearance distances, surrounding heat sources, and mechanical installation requirements.

A suitable PCB layout should also provide sufficient copper area and thermal paths around the transformer according to the actual power level and operating conditions.

How a Full-Bridge Converter Works With the Transformer

High-Frequency Switching Transfers Energy

In a full-bridge converter, switching devices generate an alternating high-frequency waveform from the DC input. The transformer receives this waveform through its primary winding and transfers energy to the secondary side.

The transformer simultaneously provides voltage transformation and electrical isolation. Its performance is therefore closely connected with the switching devices, control circuit, rectifier, filter, and load on the secondary side.

Turns Ratio Influences Voltage Transformation

The 28:6:6 winding arrangement determines the basic relationship between the primary and secondary windings. However, the actual output voltage cannot be determined by the turns ratio alone.

Switching frequency, duty cycle, input voltage, losses, rectification method, regulation strategy, and load conditions all influence the final electrical output. Engineers should therefore evaluate the transformer as part of the complete converter rather than as an independent component.

Why Leakage Inductance Matters in High-Frequency Applications

Influencing Switching Performance

Leakage inductance represents the portion of transformer inductance caused by incomplete magnetic coupling between windings. In high-frequency power converters, this parameter can influence voltage spikes, switching losses, electromagnetic interference, and overall efficiency.

For this reason, the specified leakage inductance should be considered during power-stage design, especially when the converter operates at high switching frequencies or has strict efficiency requirements.

Matching the Transformer to the Converter

The PEE4301-001 provides defined leakage-inductance limits under specified test conditions. Engineers should use these values together with the converter's switching characteristics when evaluating compatibility.

When replacing an existing transformer, even relatively small differences in inductance, winding resistance, or leakage characteristics may affect the behavior of the power stage. Sample testing is therefore recommended before approving a substitute component.

Insulation Performance Is Critical for EV Charging Equipment

High-Potential Testing

High-potential testing is used to verify the dielectric withstand capability between designated electrical sections. The published specifications for this transformer include high-voltage withstand testing between primary, secondary, and core sections.

For EV charging equipment, the transformer insulation system should be evaluated together with the complete equipment design. The component's test voltage should not be considered separately from the final charger's applicable safety requirements.

Insulation Resistance

The specified minimum insulation resistance is 100 MΩ at DC500V for the applicable primary-to-secondary and coil-to-core measurements.

High insulation resistance helps reduce unwanted leakage paths between electrically isolated sections. For commercial charging equipment, buyers should also verify the required working voltage, transient voltage, environmental conditions, and certification requirements of the final system.

Temperature Performance and Thermal Management

Wide Operating Temperature Range

The published operating temperature range of the PEE4301-001 is -40°C to +125°C. This range can support charging equipment operating in environments with significant temperature variation.

However, a wide rated temperature range does not eliminate the need for thermal management. Actual transformer temperature is affected by copper losses, core losses, switching frequency, load profile, PCB layout, airflow, and the temperature of nearby components.

Evaluating Temperature Rise Under Load

For high-power charging equipment, engineers should test the transformer under representative continuous-load conditions. Temperature rise should be evaluated at the expected maximum operating point rather than only under short-duration laboratory tests.

This approach helps identify whether the transformer remains within its specified temperature range throughout normal charging operation.

Applications for EV and New-Energy Equipment

EV Charging Piles

EV charging piles contain multiple power-conversion stages that require controlled voltage transformation and electrical isolation. A suitable transformer can be integrated into the relevant high-frequency power stage according to the charging architecture.

For charging-pile manufacturers, transformer selection should take into account rated power, input and output voltage, switching frequency, isolation requirements, available PCB space, and expected operating temperature.

New-Energy Power Systems

Similar transformer structures can also be considered for other new-energy power electronics applications. Depending on the electrical topology, magnetic components may be used in energy conversion, isolated auxiliary power supplies, renewable-energy equipment, and related systems.

Application suitability should always be confirmed through electrical design calculations and prototype testing.

What EV Charger Manufacturers Should Check Before Ordering

Define the Power-Conversion Topology

The first step is to identify the converter architecture. Full-bridge, half-bridge, LLC, flyback, and other topologies impose different requirements on transformer design.

Buyers should provide the manufacturer with the input voltage range, output voltage, rated power, switching frequency, duty cycle, isolation requirements, and operating conditions.

Confirm Mechanical Dimensions

The published transformer dimensions are 62 × 45 × 30.1 mm. These dimensions should be checked against the PCB layout, enclosure height, neighboring components, cooling structure, and required safety distances.

For new product development, mechanical integration should be evaluated before final PCB design to avoid clearance or installation problems during mass production.

Test Samples Before Mass Production

Prototype testing should include electrical and thermal measurements under representative operating conditions. Engineers may evaluate inductance, leakage inductance, winding resistance, temperature rise, dielectric withstand, insulation resistance, and overall converter efficiency.

This validation process is particularly important when the transformer is used in a new charging platform or when replacing an existing supplier's magnetic component.

Quality Control for EV Charging Transformers

Transformer consistency can directly affect the production stability of power-electronic equipment. Variations in winding structure, core assembly, insulation materials, soldering, dimensions, and electrical parameters may influence the performance of the finished converter.

For this reason, EV charger manufacturers should evaluate suppliers based on production consistency, electrical testing, process control, traceability, sample validation, and technical documentation rather than focusing only on unit price.

JASN, operated by Jansum Electronics Dongguan Co., Ltd., focuses on magnetic components including power transformers, planar transformers, inductors, Ethernet transformers, telecom transformers, solar inverter inductors, and other components for power electronics and new-energy applications.

JASN's Approach to New-Energy Magnetic Components

JASN provides different magnetic component configurations for power conversion and new-energy applications. Its planar transformer product range includes different power ratings, winding configurations, package structures, inductance characteristics, and dimensional options.

This type of product portfolio allows engineers to select magnetic components according to the requirements of their specific converter rather than relying on a universal transformer specification.

A Practical Procurement Process for EV Charging Transformers

For B2B buyers, transformer procurement should begin with a complete technical specification. The supplier should receive information about input voltage, output voltage, rated power, switching frequency, topology, isolation level, operating temperature, PCB limitations, and expected duty cycle.

Based on these parameters, the transformer manufacturer can evaluate the appropriate core structure, winding configuration, turns ratio, insulation system, package, and electrical specifications.

Samples should then be tested within the complete power-conversion system before mass production. This approach can reduce compatibility risks and help ensure stable performance across production batches.

Why Transformer Selection Affects EV Charging Reliability

EV charging equipment is a complex power-electronic system, and the transformer is an important component within its energy-transfer architecture. Its electrical, mechanical, thermal, and insulation characteristics must work together with the rest of the converter.

The EV Charging Transformer from JASN combines a full-bridge configuration, 1200W rated power, 28:6:6 turns ratio, DIP package, and a stated operating temperature range of -40°C to +125°C.

For EV charger manufacturers, charging-pile developers, and new-energy equipment integrators, the right transformer should be selected according to the complete power-conversion system. Evaluating electrical parameters, insulation performance, thermal behavior, mechanical dimensions, and production consistency before procurement can help create a more stable and reliable charging solution.