1 Introduction to High-Power Motor Applications

High power motor applications can range anywhere from lower voltage systems that result in hundreds of watts, such as a 12-V automotive power seats, to multiple kilowatt systems, such as 60-V and 100-A power tools. Typically, these systems use shunt-based current sensing, and non-isolated gate drivers that control large power MOSFETs. While these applications can be powered from a battery or gridded AC power converted to DC, they all have the common goals to be robust and protected against high current and high voltage events that result from shoot-through, short-circuit, overcurrent, MOSFET reverse recovery, or PCB parasitic inductance behavior.

For example, power tools have high power ratings for industrial and household purposes, such as drilling, grinding, cutting, polishing, driving fasteners, and more. Requirements include:

Small form factor, as tools are often hand-held
High efficiency, as tools are often battery operated
High current, as tools must produce high torque to overcome large loads
High reliability, as safety is a primary concern if the tool fails
Good thermal performance, as high power densities without proper dissipation cause systems to overheat

When designing high power systems, these requirements produce tradeoffs and conflict with each other. In the case of power tools, high current, efficiency, and thermal performance can be an increased with a larger board size which conflicts with the need to be small and hand-held.

This makes high power design very important. Like in the case of Electromagnetic Interference (EMI), designing for high power applications is a process of making decisions and planning to mitigate problems that may or may not occur.