Abstract: An example of a system to provide energy storage capacity moveable between multiple locations is provided. The system includes a plurality of docking stations, wherein each docking station is connected to a power distribution network. In addition, the system includes an energy storage unit to connect to a first docking station selected from the plurality of docking stations. Furthermore, the system includes a transporter onto which the energy storage unit is mounted to transport the energy storage unit from the first docking station to a second docking station.

Abstract: An example of an apparatus to connect a power distribution network with an energy storage unit. The apparatus includes a mobile platform. In addition, the apparatus includes a connection system to connect with an energy storage unit and to receive a current from the energy storage unit. Furthermore, the apparatus includes a transformer mounted on the mobile platform to convert the voltage from the connection system to the voltage of a power distribution network. The apparatus also includes an output cable to connect with the power distribution network.

Abstract: Feedback-type control systems for power converters that assist the power converters in staying within operational limited during disturbances. In some embodiments, each control system includes an impedance current regulator controlled as a function of an error between a measured feedback voltage signal representing the output of the power converter and an active feedforward voltage signal. In some multiphase embodiments, the impedance current regulator includes a gain that is adjusted as a function of the level of phase imbalance among the multiple phases. In some multiphase embodiments, a total current limit is determined as a function of the level of phase imbalance among the multiple phases. Corresponding feedback control methods and software, as well as power converter systems and AC network systems incorporating such feedback control systems, are also disclosed.