Patrick,
Can it change the frequency and voltage on Antminer B3?
I actually don't know, because I don't have access to this ASIC miner. Awesome Miner has a feature to change frequency (toolbar: Tools -> Antminer -> Configure Frequency), but it only works on some Antminers.
No, it can't. There is the option but it does nothing.... Miner always returns to the default 750 MHz.