Power Design with Ferrite Core for Inductors and Transformers

Power Design Ferrites are the right type of material for inductors and transformers as they offer twin advantages of low core pricing and low core losses. Generally, they are used in the frequency of 20 kHz To 3 MHz and in the saturating mode which requires low power and low-frequency operation. Power Design Ferrites are available in a variety of shapes and sizes, which makes them ideal for different applications.

The optimal design of a magnetic device with a ferrite core for power applications is governed by the following two factors-

1. Saturation Flux Density
2. Allowable Temperature Rise

Power Design for Inductors

Ferrite cores for inductors benefit users with low market prices, low losses, self-shielding, tolerance for power, flexible shapes, and more compared to most other magnetic materials. This is possible because ferrites are oxide materials and not metals, so they have to bear a dilution effect of the large oxygen ions.
Power materials are the best option to change regulators as their temperature and DC aspects match up to the required levels. If air gaps are added in the designing of the ferrite cores, they can prove to be more efficient with no or minimum saturation. The right selection of cores that support the design of inductors helps in switching regulators. When it comes to any inductor, usually, the decision of selecting materials is taken based on several factors like: 

• Costing 
• Winding 
• Assembly
• Space efficiency
• Temperature rising and rating, and others

Power Design for Transformers

While choosing a power transformer design, two factors must be considered—it should minimize the core losses and keep the core out of saturation. Most of the time, ferrite cores and tape wound cores with high permeability are used for transformers. Ferrite cores are usually preferred out of the two because they offer advantages like low losses, low costs, high permeability, and are available in a range of sizes and shapes, serving different purposes. For example, EC cores ensure minimum winding resistance along with standard channels while RM Cores increase magnetic performance and are important for temperature stability.

Ferrite Characteristics for Power Application

Here are a few important characteristics of ferrites for power applications that we can’t miss:

• High saturation flux density at elevated temperature
• Low loss at the operating frequency, high flux density & elevated temperatures
• Minimum losses in the operating temperature range (usually 70°C - 100 °C)
• High resistivity to minimize the eddy-current core loss

 
Also, while making the selection of ferrite core shapes for high frequency and high power applications, the following properties need to be checked.

• Adequate flux carrying capability
• Minimization of the winding resistance and leakage inductance
• Minimization of thermal resistance
• Good magnetic shielding
• Adequate space for safety isolation
• Simple and low-cost winding, termination and assembly
• Lowest cost of power handling capacity per unit volume

Ferrite Core Shapes & Applications:

1. E, I Cores: E, I Cores are slightly lower-priced than POT Cores and carry the advantage of simple assembly. However, the cores do not have a self-shielding quality. Common applications of these cores include differential, power and telecom inductor, broadband, and inverter transformer.

2.EFD/ EFF Core: As per the industry standards, EFD cores are E-shaped, allowing the maximum utilization of space in transformers and inductors. These cores are an accurate choice for compact transformers and inductor applications.

3. ETD/ EER Core: These cores are less expensive, which makes them a good choice for transformers or inductors. Common applications of the ETD/ EER Cores include differential inductors and power transformers. 

4. EC Cores: EC Cores have standard channels for clamping assemblies. Their center post design ensures a minimum winding resistance in the cores. Common applications of EC Cores include differential inductors and power transformers, and EC printed circuit bobbins. 

5. U, I/UR Cores: U-shaped cores are suitable for operating on a higher power when there are space constraints or uncommon form factors. They have long legs that support low leakage inductance and encourage economical assembly. Common applications for these cores include power transformers.

6. Planar E & Planar I Core: Planar E cores are designed with an adjustable leg length and window height. On the other hand, I Cores also have a standard flexible design. So, the combination of these cores is widely used for making gapped inductor cores that have a plain surface. Common applications for these cores include differential inductors and DC/ DC, AC/DC converter.

7. POT Core/ PTS: POT Cores offer the advantage of self-shielding, convenience, good temperature, low losses, and much more. Common applications for POT/ PTS Cores include broadband and narrow transformers, and telecom inductors, power transformers, power inductors, and inductive switches.

8. PQ Core: PQ Cores are commonly used in power applications. They ensure good stability across load conditions and maximum inductance along with simple assembly. The cores are built in both types, gapped and ungapped. Common applications for PQ Cores include SMPS and power inductors.

9. RM Core: RM Cores are built to increase magnetic performance to the fullest. The cores allow simple tuning adjustments, reduce losses, and facilitate temperature stability. Common applications for RM Cores include differential inductors, power inductors, filter inductors, telecom inductors, and broadband transformers. 

10. EP Core: EP Cores are built-in round center post shapes to lessen the effect of air gaps that are formed along the magnetic path. They have a round leg in the center that helps to prevent winding losses. Common applications for EP Cores include differential & telecom inductors, and power transformers. 

Conclusion

At Cosmo Ferrites, we have a wide range of ferrite cores available for different applications. Our products ensure low coercivity and low losses at high frequencies which is why they are the best choice for use in transformers and inductors. Contact us to know more about our products and services.