Introduction

In electric vehicles (EV), power inductors are critical for efficiently converting electrical energy to meet the demands of various onboard systems. Their performance directly affects the vehicle’s overall efficiency, power delivery, and safety. As EV technology advances and market demands increase, optimizing the performance of onboard power inductors has become essential.

In practical applications, power inductors generate heat during energy conversion, which, if not properly managed, can reduce efficiency, shorten operating lifetime, etc. Thus, addressing inductor’s thermal aging has become a critical industry focus.

Part 1: Causes of Power Inductor Thermal Aging

1. Current Overload

Current overload is a major cause of heating in power inductors. When current exceeds the rated capacity, resistance converts electrical energy into heat, especially during high-demand situations like acceleration or climbing. Moreover, current overload degrades magnetic properties, leading to permanent damage, higher maintenance costs, and increased failure rates.

2. Material Characteristics

The material characteristics of inductors significantly influence heating. The magnetic permeability of core materials and the resistivity of winding materials are key factors. In low-frequency applications (50Hz/60Hz), high-permeability materials can reduce copper losses. However, at higher frequencies (100 kHz to 500 kHz or more), core losses may exceed copper losses if use high-permeability materials.

Therefore, material selection must be optimized for specific applications. In low-frequency applications, the focus is on the core's DC bias capability, while in high-frequency applications, it's important to balance core losses with copper losses. Choosing the right materials and optimizing their performance is crucial to controlling heat in power inductors.

3. Design Factors

The inductor's design, including its structure and dimensions, directly impacts thermal issues. Factors such as winding layout, core shape, and size affect magnetic field distribution and current paths. For example, a compact winding design can hinder heat dissipation, while improperly sized cores may lead to magnetic saturation and increased heat generation. Therefore, thoughtful design is crucial for minimizing heat while meeting performance requirements.

4. Environmental Conditions

Environmental conditions also affect inductor thermal issues. High temperatures can reduce cooling efficiency and increase heating, while high humidity may alter material properties. Poor airflow can restrict heat release, leading to increased operating temperatures. Thus, environment factor is important for reducing heating.

Part 2: Impacts of Heating on Automotive Systems

1. Reduced Efficiency

Thermal aging in power inductors negatively impacts the efficiency of EV DC-DC converters. Increased resistance due to heat results in energy being lost as heat rather than being converted into usable power. This loss not only decreases conversion efficiency but also puts additional strain on the battery, reducing its lifespan and range.

2. Shortened Lifetime

Prolonged exposure to high temperatures accelerates aging in inductors, leading to failures such as insulation degradation and loss of magnetic properties. Early failures increase maintenance and replacement costs and can destabilize the power system, potentially resulting in safety issues.

3. Safety Hazards

Overheating inductors pose significant safety risks, including potential fires or explosions, especially when located near high-energy components like batteries. Ensuring that inductors operate within safe temperature limits is critical to preventing serious accidents.

Part 3: Solutions

1. Material Improvements

Choosing appropriate materials is fundamental for addressing inductor heating. Core materials with high saturation flux density, low losses, and high reliability are essential. In high-frequency applications, materials like iron-silicon-aluminum and ferrite are effective in minimizing losses. Optimizing wire materials, such as using litz wire or flat wire, can further reduce resistance and heat.

2. Structural Optimization

Optimizing the inductor structure enhances thermal performance. Utilizing open designs or adding heat sinks can improve thermal exchange. Innovative winding techniques that reduce thermal coupling between layers can help lower localized temperatures.

3. Cooling Technologies

Employing active cooling methods, such as fan-assisted or liquid cooling, can effectively manage inductor temperatures, particularly in high-power applications. These technologies are essential for ensuring stable operation.

4. Control Strategy Adjustments

Implementing intelligent control strategies can optimize current distribution in EV power systems. Dynamic current management adjusts current levels based on real-time load and temperature, reducing heat generation. Temperature monitoring systems can trigger adjustments to prevent overheating.

Part 4: VSBX Series Inductor Design and Applications

CODACA Electronics has launched the VSBX series of automotive grade high current inductors, designed to meet the requirements of the automotive applications. The VSBX series effectively reduces heating issues through innovative materials and advanced design principles.

The automotive grade high current power inductors VSBX series utilizes high Bs core materials, which offer excellent DC bias performance and saturation resistance, ensuring stability under high current conditions while minimizing losses and heat generation. Its compact flat wire winding construction reduces size while reducing heating by increasing the surface area of and facilitating better heat dissipation.

Additionally, the optimized magnetic shielding design in the VSBX series effectively resists electromagnetic interference (EMI). The inductors comply with the AEC-Q200 grade 0 international standard, ensuring stability and reliability across a wide temperature range (-55°C to +155°C).

Conclusion

The automotive grade high current power inductors VSBX series from CODACA exemplifies advanced technology in the automotive electronics field, enhancing the performance and safety of electric vehicles. By effectively addressing heating challenges, these inductors significantly contribute to the overall efficiency and reliability of EV power systems.