... . 3. Double DSP controller .... Features:1. Three phase in and out system, compatible with utility of 380/400/415V, 50/60Hz2 ... all kinds of load, high overload capability4. Fully digital control with three DSPs including IGBT rectifier, inverter, charger5. Digital circulating current control ... lower than 3.5mA, no flashover in 1 minuteSurge protectionComply with IEC60664-1 class IV, endure surge of 1.2/ ...