Power inductor – a device used to store energy, reduce signal and core losses, and filter EMI noises in applications where voltage conversion is required. It is usually an electrical component that can both receive as well as store energy with the use of a magnet field usually created by tightly coiled conductive wire. The main purpose of using power inductors is to maintain the steady current in an electrical circuit with varying current and/or voltage.
They are mainly distinguished using criteria such as inductance, rated current, DCR, saturation current, and frequency range. However, they can also be categorized by their construction.
Generally, small size or low current power inductors are mainly designed for electronic devices and high current power inductors are purposely designed for large scale power generation and distribution applications.
Types of Power Inductors
While there are different types of inductors, we can divide them into three main categories such as:
- Flatwire inductors
- Coupled inductors
- Compact SMD power inductors
Flatwire Inductors
These inductors are designed by using a flat wire in place of conventional round wire. They come with several advantages such as large wire surface, low winding capacity, high packing density, low DC resistance, and high operating temperature.
Coupled Inductors
They are constructed with two magnetically coupled discrete inductors. They are known for current ripple cancellation, low leakage inductance, and increased efficiency.
Compact SMD Power Inductors
These are low profile inductors mainly designed for surface mount devices. They have the benefit of wide inductance and low DC resistance. They are ideal for highly efficient DC/DC switching controllers due to low space requirement.
How to Choose a Power Inductor
Since there are so many types of power inductors available in the market, it is important to make the selection based on the current in which the core saturates and exceeds the application’s peak inductor current. Apart from the current value, there are other factors to consider such as:
- Size
- Geometry
- Temperature capacity
- Winding characteristics
- Power levels for voltages and currents
- Requirements for inductance and current
Choosing your power inductor after knowing all these factors will help you make a better selection.
Uses of Power Inductors
There are mainly three ways a power inductor can be used.
- To filter the EMI noise in AC inputs
- To filter low frequency ripple current noise
- To store energy in DC-to-DC converters
The filtering is based on the characteristics of specific types of power inductors. The units generally support ripple current and high peak current.
So, decide whether you need a low current or high current power inductor for your application. As there are many power inductors available, it is important to choose a design which also offers lower lifetime cost.