I agree that this design requires a larger number of power transistors. This increases the overall cost. But this replaces a mechanical gear box, plus differential, plus...
And I don't understand why power transistors should be larger than for other designs for similar power motors.
series resistance is the limiting issue with this design.
Things helping this issue:
Larger slow, low RdsON devices can be used (compared to PWM optimized devices)
Things hurting this design:
Way to large a volt second bandwidth across "gears". So components will be large for the worst case.
also current bandwidth is large increasing component size and cost to be able to handle worst case.
Clever and interesting nun the less.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Are the design challenges the same as with embedded systems, but with a little developer- and IT-skills added in? What do engineers need to know? Rick Merritt talks with two experts about the tools and best options for designing IoT devices in 2016. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.