I am actually using a motor controler that does this for my ebike. The Company called Adaptto witch i represented at the Interbike 2015 last year at Las vegas, are offering complete ebike motor controller with display, BMS and charging wide voltage acceptance solution. as well these are made more for DIY ebike and small electric motorcycle and offer controler up to 14kW or 28kW for the dual controller for 2WD. these can work up to 92V and 350A motor current.
The charging option is in fact using the controller output phase mosfets to PWM an external LC circuit (coil in serie with capacitor in parallel). This allow charging at any input voltage from 12V to Vbatt as the coil in conjunction with the controller work together as a boost converter. This is brilliant and simple way that allow you to charge your battery at high power using cheap power supply like the eltek, HP and other server power supply found on ebay for about 20$ per kW
The same principle (PWM acheived by the controller output mosfet controlling the coil and caps) to get the desired voltage and current to the battery can be implemented to any controller in fact. But this goes for a DC source to convert to another DC output to charge.
Now to use AC 240V as the input, the 240v is the RMS input and the peak voltage is 1.41 time higher witch mean 340V. If you add the safety margin this bring the voltage to abot 400Vdc that the mosfet of the controler need to handle.. At this voltage the popular cheap mosfet have less current handling for the packaging same size so it require more mosfet.. ex: a 150V mosfet like the gen4 80V model use can handle higher current than a 400V mosfet the same size can do...
The problem with that is the voltage that the controller are designed to work with and the voltage the AC source require when the controller power stage need to be used for both application... IF the Zero batery could move from from 28s to 96s, this would be done easy as 96s battery have about the same voltage as the 240V peak + margin are... however i think that at Zero they will remain with <150V for long..
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