Superconducting Magnetic Energy Interaction Model And Its Applications

Superconducting magnetic energy storage(SMES) systems having the outstanding advantages of high storage efficiency, high power density and fast response speed behave significant research potentials for efficient, fast and smart energy management applications in future smart grid. However, the superconducting magnet in a SMES system belongs to applied superconductivity field, while its power conditioning system belongs to electrical engineering field. The differences between the above fields limit the extensive utilizations of SMES in the modern power system. To have both the superconducting features and energy interaction features integrated in one model, this work proposes and investigates a novel superconducting magnetic energy interaction(SMEI) model and accessorial experimental platform based on a circuit-field-superconductor coupled method, and then explores several novel application schemes in modern power system and future smart grid. The main contents, contributions and innovative points are presented as follows:1. From the view of energy interaction analysis, this paper develops a novel energy interaction circuit model based on the essential features and equivalent circuit transformation approach of SMES to solve various power system problems. The developed model provides an equivalent power system circuit model for the researchers in the applied superconductivity field, and thus makes it more convenient to calculate the anisotropic and AC loss characteristics and to carry out various optimization designs for the SMES coil structure and refrigeration system.2. From the view of circuit-field-superconductor coupled analysis, this paper develops a novel coil-current-dependent superconductor model based on the anisotropic and AC loss characteristics of SMES. The developed mode provides an equivalent SMES component having independent input-output relationships and current-dependent superconducting characteristics.3. Based on the developed SMEI model, an SMEI experimental platform is built to carry out the performance tests and evaluations of SMES before its practical applications, and to lay a valuable foundation for the optimization designs for the SMES coil structure and power conditioning system. In addition, a bridge-type chopper operated at room or cryogenic temperature is proposed and experimentally verified to behave much higher operation efficiency over the conventional chopper.4. For the feasibility studies of SMES-based frontier applications, this paper explores a SMES-cryogenic liquid hydrogen-fuel cell integrated application scheme and a SMES-cryogenic liquid hydrogen-superconducting DC cable integrated application scheme, and thus presents the conceptual designs of SMES-based liquid hydrogen powered fuel cell electric vehicle and SMES-based low-voltage direct-current micro grid. Finally, four SMES application modes are put forward for the SMES applications in the power generation, transmission, distribution and utilization systems of the future smart grid.