Electromagnetic Components for Aerospace Electric Power Systems

Most electronic systems, including electric motor drives and electric power conditioners, require the use of electromagnetic devices, such as inductors and transformers as circuit components to carry out any of the following functions:

1. a)
   Suppressing or isolating specific harmonic components in voltages and currents.
2. b)
   Providing electrical isolation from one circuit to another.
3. c)
   Limiting the currents under fault conditions.
4. d)
   Increasing or decreasing the voltage or current levels.
5. e)
   Integrating voltages, currents, or power.
6. f)
   Providing neutral line, phase shift.

The performance of the electronic systems is dependent upon the design of the electromagnetic components that are used. For the aerospace quality hardware, the weight, size, cost, reliability, and efficiency of the electronic systems are substantially dependent upon the design of electromagnetic components.

The diversity of functions carried out by the electromagnetic components result in a great variety of components that use different iron structures, winding arrangements, and insulation schemes. The iron structures, laminated or powdered, are selected on the basis of eddy current and hysteresis losses, as well as magnetic saturation characteristics. Winding schematics and connections are dependent upon specific functions and the number of phases. Insulation schemes are selected to effectively isolate the electrical windings from each other as well as from the ground without creating excessive thermal barriers.

While the basic technology of designing the electromagnetic components is fairly mature, applications in aerospace systems require great attention and care in addressing the following issues:

1. a)
   Terminal requirements -- proposed conditions of voltage, current waveshapes at the input (and output) terminals.
2. b)
   Selection of materials.
3. c)
   Electromagnetic analysis: performance, losses.
4. d)
   Thermal considerations.
5. e)
   Insulation.

This paper will address these issues in relation to trading of size, cost, reliability and efficiency versus specific performance parameters for these components.