A new nonlinear control approach of superconducting energy storage is devised under the condition of addressing the voltage imbalance of the distribution network in order to obtain more precise control of superconducting energy storage devices (SMEs). The model of the superconducting energy storage device is built on the basis of determining the voltage imbalance signal of the distribution network. Aiming at the situation that the voltage of the device will change at the same time when the structure of the device changes, a nonlinear controller is designed to estimate the discontinuous interference state of the nonlinear controller device and combined with the nonlinear control algorithm to realize the nonlinear control of superconducting energy storage. The simulation test results demonstrate that the design method can accomplish a more accurate signal tracking cut and that switching voltage generation estimation is performed well. It shows that the design method can meet the actual nonlinear control requirements of a superconducting energy storage device.