Hello! As many might have noticed from Surplus motors thread I have been designing my own servo drive especially for those Sanyo P5 motors. Many of Sanyo owners seems to be interested about my drive so I must ask for some opinions to get the idea what kind of drive is most wanted.
I already have a working "proof of concept" running and I'm starting to build a real prototype soon. First thing to decide is the type of the power stage. Some explanations of each choice:
1) Surface mount discrete MOSFETs: Continuous output power would probably be limited to about 500 Watts. However it has the most solid contruction and the lowest total component cost.
2) IRAMS10UP60A power module (3 phase 600V 10A max). An easy solution (speeds up design process) but the voltage rating is somewhat unoptimal for 100Vac motors. Maximum output power would be around 500-800W.
3) Discrete through-hole MOSFETs with heatsink. Over 1kW output power possible but has most undesirable construction. Many parts to cool down and heatsink must be insulated etc.
4) SMD discrete MOSFETS + possibility to connect own custom external power stage of any power. Enough power for most applications (<500W) but enables to drive higher loads too. Requires lots of time to get it well tested.
5) Controller logic only without integrated power stage. An external power stage must be used. Virtually any power possible.
A typical power stage consists a) six power transistors, b) gate drivers for transistors, c) current sensing circuity and possibly d) short circuit protection (optional).
Those 1kW servos have peak power rating of 3kW for 10% duty cycle. Because motor efficiency is not 100% it would require about 4kW power stage to squeeze everything out of motors. That kind of power stage can be complex and expensive.
I wonder what kind of CNC machine it takes to utilize that kind of power. It must be a massive industrial size machine weighting tons that rapids at 1000 IPM. How many of you are planning to build one? I don't think its very good idea to pay for 4kW drives if you really need "only" 400W. Anyway I'm open to suggestions.
Xerxes