The application relates to an electric converter for converting AC or DC input into an electric AC or DC output. A swap circuit with controllable electric switches serves to selectively swap connection of a plurality of DC power banks (DCBs) between an input terminal and an output terminal, thus selectively connecting the DCBs to an electric source or an electric load. The DCBs are formed as series of interconnected submodules (SMs) each having electric energy storage elements (ESEs) and a switching circuit for selectively by-passing or connecting the ESEs. By properly controlling the swap circuit and the switching of the SMs, the converter can be used for DC-AC, DC-DC, AC-DC, or AC-AC conversion, allowing multilevel output.

A device includes an input converter, an output converter, and a controller. The input converter is electrically coupled to an electrical meter and an energy production array. The output converter is electrically coupled to the energy production array and a load. The controller is communicatively coupled to the input converter, the output converter, the energy production array, and the load. The input converter and the output converter are positioned between the electrical meter and the load.

A method includes generating a time-varying charge/discharge control signal for an electrical storage device, wherein generating the time-varying charge/discharge control signal comprises identifying a prioritization order of a stack of simultaneously operating control modes, the stack of simultaneously operating control modes including a staging mode and at least two additional control modes, each control mode of the stack comprising a plurality of control signal candidate values; identifying an intersection of one or more control signal candidate values from the plurality of control signal candidate values of each control mode of the stack according to the prioritization order; and determining, based on the prioritization order, at least one time-varying charge/discharge control signal for the electrical energy storage device from the intersection of control signal candidate values.

The invention discloses an islanding detection method in DC microgrids based on MPPT trapezoidal voltage disturbance. The steps are as follows: start the MPPT strategy; set the starting signal threshold of disturbance; measure the output current of PVA at the maximum power; calculate the same environmental factor of PVA with different capacities under the same light intensity and temperature in real time; when the environmental factor is greater than the starting signal threshold of the disturbance, periodic trapezoidal disturbance is carried out to the PVA port voltage reference; if the PCC voltage Upcc exceeds the threshold set by the passive method, it is judged as islanding; otherwise, it is judged whether the change rule of Upcc is consistent with the change rule of the calculated PCC voltage Upccp under the trapezoidal disturbance; If it is consistent, it is judged as islanding; otherwise, it is pseudo islanding.

In order to output sufficient reactive power for voltage stabilization of a utility grid, and calculate an appropriate consideration according to an amount of the output reactive power, is provided a control device for controlling a distributed power source connected to the utility grid, comprising: a range setting unit where an allowable range of reactive and active powers output at normal times is set; an output control unit for controlling the reactive and active powers supplied from the distributed power source to the utility grid within the allowable range set in the range setting unit; and a reception unit for receiving, from a command device in the utility grid, an excess output command indicating that the reactive power exceeding the allowable range should be output, wherein the output control unit is for outputting the reactive power out of the allowable range when the reception unit receives the excess output command.

A wireless power transfer pad for wireless charging of a vehicle electrical storage system. The wireless power transfer pad includes an oscillating electromagnetic field generating device configured for transmitting energy to a wireless power receiver associated with the vehicle. The pad further includes a foreign object detection arrangement including a plurality of foreign object detection coils. The solar panel arrangement includes a photovoltaic substrate with a front side and a rear side, a front side electrode arrangement and a rear side electrode arrangement. The foreign object detection coils are configured to function also as the front side electrode arrangement.

A photovoltaic system includes a controller and plurality of photovoltaic strings that are independently controlled. The controller enables some photovoltaic strings to be in a maximum power point tracking state, and the remaining photovoltaic strings to be in a power output limited state. The system implements maximum power point tracking detection so that the maximum power point power and the maximum power point voltage are updated in real time. Further, the working status of the power supply system can be fed back in real time, so that the photovoltaic system can predict the capacity of an energy storage apparatus or regulate charging and discharging of the energy storage apparatus. After a curtailment state ends, the photovoltaic system is relatively quickly restored to the normal working state, so that a loss of generated power is reduced.

An example system includes an aggregator configured to receive a service collaboration request and iteratively determine, based on minimum and maximum power values for DERs under its management, an optimized operation schedule. The aggregator may also be configured to iteratively determine, based on the optimized operation schedule, an estimated flexibility range for devices under its management and output an indication thereof. The system may also include a power management unit (PMU) configured to iteratively receive the indication and determine, based on a network model that includes the estimated flexibility range, a reconfiguration plan and an overall optimized operation schedule for the network. The PMU may also be configured to iteratively cause reconfiguration of the network based on the plan. The PMU and aggregator may also be configured to iteratively, at a fast timescale, cause energy resources under their management to modify operation based on the overall optimized operation schedule.

The present disclosure provides an electrical system that includes an energy control system, a photovoltaic (PV) power generation system electrically coupled to the energy control system, an energy storage system electrically coupled to the energy control system, and a smart load panel electrically coupled to the energy control system and to a plurality of backup loads. The energy control system operates in an on-grid mode electrically connecting the PV power generation system to a utility grid and a backup mode electrically disconnecting the PV power generation system from the utility grid. The smart load panel selectively disconnects one or more of the plurality of backup loads from the energy control system when the energy control system is in the on-grid mode and when the energy control system is in the backup mode.

Various implementations described herein are directed to a methods and apparatuses for disconnecting, by a device, elements at certain parts of an electrical system. The method may include measuring operational parameters at certain locations within the system and/or receiving messages from control devices indicating a potentially unsafe condition, disconnecting and/or short-circuiting system elements in response, and reconnection the system elements when it is safe to do so. Certain embodiments relate to methods and apparatuses for providing operational power to safety switches during different modes of system operation.