SoC balance control method for parallel operation of multiple energy storage units

The invention discloses an SoC balance control method for parallel operation of multiple energy storage units. The SoC balance control method comprises the following steps: estimating the SoC of the ith energy storage unit by using an ampere-hour integral method; the SoC estimated by other energy storage units is obtained through a low-bandwidth communication line, and the average SoC of the n energy storage units running in parallel is calculated locally; adaptively adjusting the droop coefficient by using an SoC equalization control algorithm to obtain a dynamic correction droop coefficient of the ith energy storage unit; a converter reference output voltage of the ith energy storage unit is obtained, and a converter reference output current of the ith energy storage unit is obtained by adopting a voltage loop PI control method; a current loop PI control method is adopted to obtain the duty ratio of a converter switching tube of the ith energy storage unit; each energy storage unit converter controls the ac