Abstract: In view of the problems of unstable operation waveforms，high output current stress and

instantaneous fluctuation difference of load in the current sharing control of two-way DC-DC converter in flexible

substation，a method of independent current sharing control of two-way DC-DC converter in flexible substation

based on three-dimensional modulation was proposed. Three dimensional modulation method was used to adjust

the capacitor voltage in DC-DC converter to balance the capacitor voltage in DC-DC converter. Dual phase shift

（DPS）method was used to analyze the current stress characteristics of the converter and calculate the phase shift

angle to obtain the current duty cycle of the converter. Finally，by acquiring the current duty cycle of the converter，the independent current sharing control of the two-way DC-DC converter in flexible substation was completed. The experimental results show that the proposed method can improve the current waveform stability of bidirectional DC-DC converter，reduce the current stress and improve the load transient fluctuation.

      Key words: three-dimensional modulation；flexible substation；autonomous current sharing control；converter；output current