A system and method for combining power from DC power sources. Each power source is coupled to a converter. Each converter converts input power to output power by monitoring and maintaining the input power at a maximum power point. Substantially all input power is converted to the output power, and the controlling is performed by allowing output voltage of the converter to vary. The converters are coupled in series. An inverter is connected in parallel with the series connection of the converters and inverts a DC input to the inverter from the converters into an AC output. The inverter maintains the voltage at the inverter input at a desirable voltage by varying the amount of the series current drawn from the converters. The series current and the output power of the converters, determine the output voltage at each converter.

A system and method provide integrated carbon-negative, geothermal-based, energy generation and storage. The embodiments produce dispatchable electricity at grid-scale by storing excess energy from the grid and generating its own energy. The excess energy may be taken from solar and wind sources. In one aspect, the subject technology is energy storage, energy generation, carbon utilization and sequestration, all in one. The technology has very high round-trip efficiency of storing energy and is carbon-negative which makes it far more sustainable than any competing energy storage technology.

The present disclosure includes methods and apparatus for HVDC power distribution. A control apparatus is described for controlling a frequency set-point for a first AC network electrically connected to a first HVDC station to regulate active power. The controller has a frequency controller operable in a first mode of operation to determine a frequency set-point (Fref) for the first AC network based on a measured DC voltage at the first HVDC station. A disturbance detector is configured to monitor the measured value of DC voltage at the first HVDC station (VDC1) for a predetermined characteristic indicative that a variation in measured DC voltage does correspond to a known modulation applied to the DC voltage by a second HVDC station. The frequency controller is configured to determine the frequency set-point (Fref) for the first AC network based on a measured value of DC voltage (VDC1) if said predetermined characteristic is detected, and to control the frequency set-point to a predetermined default frequency if said predetermined characteristic is not detected.

The present application provides a method and a system for controlling continuous low voltage ride-through and high voltage ride-through of a permanent magnet direct-driven wind turbine. The method includes: determining a transient time period during which the wind turbine is transitioned from a low voltage ride-through state to a high voltage ride-through state; controlling the wind turbine to provide, during the transient time period, a gradually increasing active current to the point of common coupling; and controlling the wind turbine to provide, during the transient time period, a reactive current to the point of common coupling according to an operation state of the wind turbine before the low voltage ride-through state.

A multi-port converter includes a hybrid energy storage system (HESS) that provides a faster dynamic response to load changes than prior art systems, and enables either downsizing of the main energy storage system (ESS) to increase the life of the main ESS (e.g. energy battery), or retaining the same size ESS and increasing the range or life of the power source. The multi-port convertor can advantageously result in lower investment and maintenance costs, and can also advantageously provide a path for inputs to directly feed the load. All these benefits can be achieved while reducing the number of active switches and overall component count as compared to prior art systems.

Demand response methodologies for primary frequency response (PFR) for under or over frequency events. Aspects of the present disclosure include methods for controlling a fleet of distributed energy resources equipped for PFR and quantifying in real time an amount of primary frequency control capacity available in the fleet. In some examples, the DERs may be configured to consume and discharge electrical energy in discrete energy packets and be equipped with a frequency response local control law that causes each DER to independently and instantaneously interrupt an energy packet in response to local frequency measurements indicating a grid disturbance event has occurred.

A server that manages energy of a power grid by using a plurality of energy storage resources includes a loss obtaining unit and a selector. The loss obtaining unit obtains for each of the plurality of energy storage resources, energy loss including retention loss and input and output loss, the energy loss being caused in storing energy in each energy storage resource. When surplus electric power occurs in the power grid, the selector selects at least one energy storage resource for storing surplus electric power from among the plurality of energy storage resources based on the energy loss caused in storing surplus electric power.

Provided are a substation system including an energy storage device, a method of calculating capacity of the energy storage device, and a control apparatus for the same. The control apparatus may include a charge and discharge determination unit configured to determine a charge or discharge operation of an energy storage device based on whether a measured output value is within an output operation range; a forecast error determination unit configured to determine a ratio of a period in which the measured output value is out of the output operation range with respect to a total period; and a capacity determination unit configured to determine capacity of the energy storage device based on the ratio.

An energy offloading system is in direct electric communication with an energy supply and dynamically receives energy from the energy supply. The energy offloading system uses energy for high-load computations. The energy offloading system includes computers performing the high-load computations as well as servers, cooling units, and communication devices. When the energy from the energy supply is terminated, the energy offloading system may power down these and other devices, or may switch these devices to an alternative power source. The energy offloading system may be portable.

A grid-forming wind turbine control method for a diode rectifier unit-based offshore wind power transmission system. A control system for controlling a grid-side converter has a three-layered structure, where a first layer is a combination of an active power controller and a reactive power controller; a second layer is a voltage controller; and a third layer is a current controller. The actual reactive power is represented by a per-unit value of a capacity of a corresponding wind turbine unit. The wind turbine units have the same reactive-power reference value, which is constant and does not change with time. The reactive power controllers of all wind turbine units have the same structure and parameters.