Combined Dual modulation Scheme (CDMS) for high power converters in Spacecraft All Electric Propulsion Systems (AEPS)

All Electric Propulsion Systems (AEPS) is replacing chemical propulsion and has became popular configuration for satellite propulsion system due to various advantages. The AEPS spacecraft operates at High Thrust, Low Specific i mpulse (Isp) and/or Low Thrust, High Isp modes to meet the mission requirements. The power processing unit feeding the electric thrusters are to be designed for wide load and line variations. Dual active bridge (DAB) converters are becoming popular in Aerospace and AEPS missions. Aim of this work is to develop a novel control scheme and analytically prove that higher efficiency (thru minimum RMS or peak current) and improved performance (thru increased ZVS range) can be achieved over entire AEPS operating regime. In this paper, a novel modulation scheme called Combined dual modulation scheme (CDMS) is presented. The analysis of the same is presented and the performance is verified in terms of RMS, peak inductor currents and ZVS operation of DAB converter. The control scheme is verified for simulation of DAB converter feeding a 1 kW - 5 kW system. The CDMS features better configurable output stage, wide output voltage range, high efficiency, higher power density and reduced Electromagnetic interference (EMI).