A control device is provided with: a power transfer control means that controls power transfer to and from a DC distribution network; and an exchange means that exchanges, with respect to transfer power to and from the DC distribution network, information indicating an attribute based on a power generation scheme.

A method for connecting a power transformer, located between an inverter of a wind turbine and an electrical grid, to the electrical grid; the method comprises the steps gradually increasing a voltage at a primary side of the transformer from a low starting voltage to a target voltage equal or close to a nominal voltage of the transformer, by means of the inverter of the wind turbine or by means of an auxiliary inverter, thereby increasing the voltage at a secondary side of the transformer, wherein the gradually increasing of the voltage uses energy of an internal energy storage device, connecting the secondary side of the transformer to the electrical grid after predefined target conditions have been reached.

An embodiment relates to an arrangement for equalizing voltage drops in a power supply mains having a first mains supply and a second mains supply. The arrangement includes at least one first converter system and one second converter system, to which intermediate circuits are coupled and which form a mains coupling as a result. The first mains supply is connected to a distributor via a decoupling inductor, a voltage measurement and a first switch. The second mains supply is connected to the distributor via a second switch, and wherein the mains coupling is arranged parallel to the second switch.

A switching controller generates control pulses for specifying on/off states of a first transistor and a second transistor. One end of a capacitor is coupled to a switching node. A constant voltage is applied to the other end of the capacitor via a rectifier element. A dead time controller controls a delay time between adjacent edges of the first control pulse and the second control pulse according to a sensing voltage across both ends of the capacitor.

An electric power converter includes: an electric power conversion unit configured to convert electric power that has been input, and output the converted electric power; and a control unit configured to control, based on a reference function, an electric power conversion characteristic of the electric power conversion unit, wherein the reference function includes plural droop functions that have been defined according to input values, have drooping characteristics different from one another, and have been connected to each other, and the control unit is configured to control the electric power conversion characteristic by control schemes that are different from one another and are according to the drooping characteristics of the droop functions.

An electric power converter includes: an electric power conversion unit configured to convert electric power that has been input, and output the converted electric power; and a control unit configured to control, based on a reference function, an electric power conversion characteristic of the electric power conversion unit, wherein the reference function includes plural droop functions that have been defined according to input values, have drooping characteristics different from one another, and have been connected to each other, and the control unit is configured to control the electric power conversion characteristic by control schemes that are different from one another and are according to the drooping characteristics of the droop functions.

Embodiments provide a method and apparatus for capacitor demand evaluation in a PDN that includes at least one power bus provided with multiple nodes. The multiple nodes are distributed at different positions of the power bus. Each of the multiple nodes is connected to multiple capacitors connected in parallel. Each of the multiple capacitors is provided with a respective one of control switches. The method includes: Multiple adjustment operations are performed. Upon accomplishment of each of the multiple adjustment operations, a respective IR drop of the power bus and a respective running speed of the load circuit are detected; for each of different nodes on the power bus, an ideal capacitance of the node is determined according to the IR drops of the power bus and running speeds of the load circuit detected through the multiple adjustment operations.

In large PV power plants, grounding of individual PV modules may lead to problems. The present invention overcomes such problems. The basis for the invention is a PV power plant comprising one or more PV generators, each comprising a PV string and an inverter with a DC input and an AC output. The PV string comprises at least one PV module and is electrically connected to the DC input of the inverter. The inverter comprises means for controlling the DC potential at the DC input depending on the DC potential at the AC output. The AC outputs of the inverters are coupled in parallel. The novel feature of the invention is that the PV power plant further comprises an offset voltage source, which controls the DC potential at the AC outputs. Thereby, the DC potential at the DC input will be indirectly controlled, and it is thus possible to ensure that the potentials with respect to ground at the terminals of the PV modules are all non-negative or all non-positive without grounding the PV modules. Ground loops can be avoided, and there is no need for the use of transformer-based inverters.

A power supply control device controls power supply to a load through a power supply switch. A driving circuit switches on or off the power supply switch. When the driving circuit switches the power supply switch from off to on, a waveform value regarding the current waveform of a current that flows through the load is output by a waveform value detection unit to a microcomputer. The microcomputer determines power supply control conditions regarding control of power supply to the load based on the waveform value that is input from the waveform detection unit.

System, methods, and other embodiments described herein relate to safely activating a fuel cell (FC) within a generator. In one embodiment, a method includes initiating a test for sensitive systems of a generator using backup power including a battery. The method also includes powering an FC and a direct current (DC) converter within the generator to an operational level using the battery, wherein the DC converter stabilizes a circuit fed by the FC. The method also includes, upon successfully completing the test and powering the FC and the DC converter, energizing a load inverter after completing a non-critical sequence that controls support systems of the generator, wherein the DC converter stabilizes energy between the FC, the battery, and the load inverter.