Provided is a microgrid system having: a plurality of distributed power sources; a plurality of distributed loads; and lines for connecting the distributed power sources and the distributed loads, the microgrid system including: an ESS for storing power supplied from all or a portion of the distributed power sources and supplying the stored power to all or a portion of the distributed loads; an ESS PCS including an interruption means for converting the power stored in the ESS into AC power suitable for the microgrid and supplying the AC power to the microgrid in order to block connection to the microgrid in an abnormal state; and a monitoring/control device for gradually increasing a voltage output from the ESS PCS and performing processing for the failure when a failure is detected in the microgrid.

Provided is a fault processing method of a microgrid having a plurality of distributed energy resources, a plurality of distributed loads, lines that connect the distributed energy resources and the distributed loads, and an energy storage system (ESS) that stores power supplied from a part or all of the distributed energy resources and supplies the stored power to a part or all of the distributed loads, the fault processing method comprising steps of: disconnecting the distributed energy resources and an ESS power conditioning system (ESS-PCS) responsible for the ESS when a fault is detected in the microgrid system; connecting the ESS-PCS to the microgrid; determining a location of the fault while gradually increasing a voltage output from the ESS-PCS; and disconnecting the location of the fault and boosting the voltage output from the ESS-PCS to a normal operation level.

A method and apparatus for parallel operation of multiple power sources including one fuel cell power source. The apparatus includes a droop controller master communicatively connected to the multiple power sources and configured to measure a load demand for the multiple power sources, a first droop controller slave communicatively connected to the droop controller master and to a first fuel cell power source, the first droop controller configured to calculate a first droop profile for the first fuel cell power source, a second droop controller slave communicatively connected to the droop controller master and to a second power source, and a first inverter, electrically connected to the first fuel cell power source and communicatively connected to the first droop controller slave, and configured to output power according to a first droop profile.

Nonlinear control method for the micro-grid inverter with anti-disturbance. By generating reference currents that satisfy specific active and reactive power command under various working conditions, and introducing a nonlinear control method based on Lyapunov function to control the inverter, fast and accurate tracking of the generated reference signals is realized. The method realizes effective decoupling control of active power and reactive power. The system has high dynamic response and good robustness. Besides, the control structure of the method is simple and easy to implement, and the synchronous control link and the additional voltage and current regulator are omitted. The method realizes fast and accurate power exchange and stable power transmission between the inverter and the grid in the micro-grid under various working conditions, and provides a guarantee for improving the energy management efficiency within the micro-grid.

This invention presents a new circuit topology formed by passive filter LCCL or LCC and voltage source DC/AC converter, which is named as fundamental forming unit. Compared with conventional LCL filter based DC/AC converter, the new converter circuits can handle wider range of power without suffering from disturbance by harmonic voltages and currents. For high voltage and high power application, circuits with multiple stages and multiple parallel branches are developed based on multiple fundamental forming units. Such circuits can be for general purpose application. They can also be for microgrid applications. Furthermore a new series of multistage DC/AC converters with LCL filter have also been developed to handle high power conversion at high voltage and high current levels. By applying such circuits to acting as grid-forming, grid-supporting and grid-feeding generators in a microgrid operating at constant frequency, the microgrid system can handle much higher power and can adapt to drastic change of renewable energy generation and load change. Such microgrid is operated using newly invented methods described in this disclosure.

A distributed method is provided for controlling electrical power in a microgrid, wherein a plurality of distributed generators supply electrical power to the microgrid, and each of the distributed generators is connected to a controller for controlling the real and reactive output power from the distributed generator. The method includes the steps of measuring, for each of the distributed generators, a voltage level at a measuring point associated with that distributed generator and forwarding the measured voltage level to the controller connected to that distributed generator; determining, for each of the controllers, a parameter value related to the received measured voltage level and/or related to a reactive current injection capacity of the distributed generator connected to that controller; communicating, from each of the controllers, its determined parameter value to each other ones of the controllers; determining a sequential order in which the controllers are to control the distributed generators to inject reactive power into the microgrid based on the communicated parameter values; and controlling the distributed generators to inject reactive power into the microgrid by means of the controllers in the determined sequential order.

A method for configuring a switched-mode power supply with multiple output channels, where the switched-mode power supply includes at least one operating element for each output channel, where the operating element is used to manually adjust an operating parameter for the corresponding output channel, the switched-mode power supply also includes an interface for performing a remote configuration, where each manually adjusted operating parameter is output to a remote configuring unit via the interface, and each manually adjusted operating parameter is transferred into a switched-mode power supply configuration that is set via the configuring unit such that, in a manual mode, adjusted operating parameters are transferred into the remote configuration and are used in a remote mode upon restarting the switched-mode power supply.

A microgrid control system including a plurality of distributed generators, loads and/or energy storages. The system includes a microgrid controller arrangement, and a network controller arrangement. The network controller is distributed and configured to perform measurements on the microgrid, send information to at least one other of the plurality of network controllers, and send information to the microgrid controller arrangement based on the performed measurements. The information sent to the microgrid controller arrangement relates to assets which are included in a segment of the microgrid with which the controller is associated. The microgrid controller arrangement is configured to control the plurality of assets by instructing respective converter controller of each of the plurality of assets.

Device for heating and cooling, respectively, more than one house, where at least two small houses (1) are connected to a common energy storage (2) in the ground and where a control device (3) is arranged to transport a heat carrier in a pipe work (4) connected to the energy storage (2). The small houses (1) are each arranged to have a separate respective heat pump device, and in each heat pump device is connected to the pipe work (4), so that, firstly, the heat carrier can flow through the heat pump device and, secondly, the small houses (1) are connected in parallel in relation to each other to the pipe work (4).

A method for controlling power in a microgrid that includes power sources, loads and at least one connection to a main grid where a transformer is arranged to transfer electric power between the microgrid and the main grid is disclosed. The method includes: monitoring the power balance within the microgrid; monitoring the transformer, including monitoring the transformer temperature; and detecting a need for overloading the transformer based on the power balance within the microgrid. Especially, the method includes: determining a load profile for the transformer based on the power balance within the microgrid; determining a prognosis of the transformer temperature based on the load profile; and determining a schedule for power control of the microgrid, which determining of a schedule for power control includes analyzing the prognosis of the transformer temperature.