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If you have a distributed system of DC motors, sensors and microcontrollers, is power usually distributed over a single high volt bus, using DC converters where needed? Or is it typical to implement separate power buses for each device class?
Maximum cable length from battery to device is about 1 meter, 12 V, 5 V and 3.3 V will be needed depending on the device.
What's used in practice, like in industrial equipment or large robot arms?
Electrical cables and connectors are a very common failure point in distributed electro-mechanical systems. So minimizing the number of wires and connectors is often a priority. In which case a single high voltage line distributes power to all the nodes and each one converts it down to the voltages it needs locally. Switched DC-DC converters are so common and cheap now that the cost reasons for having separate central supplies for each voltage level are no longer valid.
However, motors add noise to the power supply system and, depending on machine design, can also add a large amount of power draw (voltage*amperage) to the power supply. You will need to address these issues if you use a single bus. Motor capacitors and regenerative voltage shunt circuits are your friend for this. Also a clean wiring design that minimizes RF and inductive noise.
My personal experience is in industrial automation and controls designing utility fed electrical panels. I do not have experience with industrial battery powered equipment like AGVs but maybe you can apply some of what I share below to your needs.
Typically your main power (usually AC power) is brought in and is immediately fed into a circuit protective device and/or a power disconnect (on-off switch). From there it may be filtered, further protected with fuses or circuit breakers, and subsequently fed into devices which consume power directly from the main. When control power is required (think 5, 12, 24VDC or 120VAC) the main power is fed into a DC power supply or AC control transformer. The output from these power supplies is fed into fuses for circuit protection and made available at a central distribution point. Each branch of power is individually protected with fuses or circuit breakers.
When devices outside of the control panel require power, the power is typically transmitted through the connection cable to the device at the voltage the device requires. I would say it is very rare to see power supplies or transformers at the end device.
Since your cable run is very short, I would have no issue with centrally converting power to your requirements and only sending the power you need through the cable. This simplifies the design since you only need one central supply, and it allows you to locate all your circuit protective devices together at the power supply.
