Methods and systems are provided for optimizing the control of energy supply and demand. An energy control unit includes one or more algorithms for scheduling the control of energy consumption devices on the basis of variables relating to forecast energy supply and demand. Devices for which energy consumption can be scheduled or deferred are activated during periods of cheapest energy usage. Battery storage and alternative energy sources (e.g., photovoltaic cells) are activated to sell energy to the power grid during periods that are determined to correspond to favorable cost conditions.

Optimized energy management system

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.

Distributed Power Harvesting Systems Using DC Power Sources

A network-controlled charge transfer device for electric vehicles includes a control device to turn electric supply on and off to enable and disable charge transfer for electric vehicles, a transceiver to communicate requests for charge transfer with a remote server and receive communications from the remote server, and a controller, coupled with the control device and the transceiver, to cause the control device to turn the electric supply on based on communication from the remote server.

Network-controlled charging system for electric vehicles

A wireless base unit communicates with one or more wireless load manager units to receive power measurements for one or more loads connected to the wireless load manager. In response to dynamic variables, such as the changing price of electricity, the wireless base unit transmits commands to the wireless load manager to shut off or reduce power consumed by the one or more loads. In one variation, a wireless adapter also receives commands from the wireless base unit and converts the commands into a vendor-specific format used to control other devices such as a photovoltaic (PV) inverter.

Modular energy control system

The invention in the simplest form is a method and apparatus for reliably protecting against island situations with one or multiple power sources connected to an electric distribution grid. The method and apparatus detects variations in the voltage and frequency of the grid. An observed change in grid voltage causes a change in output power that is sufficient to cause an even larger change in grid voltage when the utility AC power source is disconnected. An observed change in grid frequency causes a change in phase or reactive output power that is sufficient to cause an even larger change in grid frequency. If several shifts in voltage or frequency happen in the same direction, the response to the change is increased in an accelerating manner.

Anti-islanding method and apparatus for distributed power generation

A pulse width of a pulse train signal used for PWM (pulse width modulation) control is monitored. When a variation of the pulse width substantially disappears within a specified time, it is determined that an operating point on an output characteristic curve of a photovoltaic array is located on the open-circuit voltage side of a maximum power point. When the variation of the pulse width does not disappear after the elapse of the specified time, it is determined that the operating point is located on the short-circuit current side of the maximum power point. Based on the determination result, the inverter control is performed such that the operating point follows the maximum power point.

Inverter control method and inverter apparatus using the method

PROBLEM TO BE SOLVED: To provide a power supply system for a distributed source, installing a distributed power source system in a plot of a power user by a power supply provider to perform power supply to the user, diagnosis of system operation, etc. SOLUTION: This system includes a distributed power source system 16, supplying power of commercial frequency to a load 8 of a specific user, additionally performing system linkage and a system managing means 15 connected to each distributed power source system via a communication network 12; the distributed power source system 16 includes a solar battery 1, a fuel cell 2, a storage battery 3, a power converter means 4 for system-linking power output from these power-generating means, a power condition monitor means 6, and a system control means 7; and the system control means 7 communicates operating information of the distributed power source system 16 to the system managing means 15 and controls the operating condition of the power converter means 4, according to the indication received from the system-managing means 15.

Power supply system for distributed source

PROBLEM TO BE SOLVED: To improve the efficiency of system generation in a system linkage inverter which has input from a plurality of solar cell arrays connected in parallel, by causing the individual solar cell arrays to independently follow maximum power. SOLUTION: In a power conversion device for photovoltaic generation having a plurality of solar cell modules 8a, 8b, 8c as power sources, each of the solar cell modules 8a, 8b, 8c is provided with step-up chopper portions 26a, 26b, 26c which follow the maximum power of the individual solar cell modules 8a, 8b, 8c, and a DC-DC converter for waveform generating portions. Maximum power is derived from respective solar cell modules 8a, 8b, 8c and is converted into an alternating-current output through a inverter 23, a DC-AC converter 36, and the like in a bundle. COPYRIGHT: (C)1999,JPO

Power conversion device for photovoltaic generation

There is provided an inverter apparatus islanding operation detecting method capable of surely detecting an islanding operation with a simple construction. A distortion for causing a variation in an output frequency of an inverter apparatus in an islanding operation stage is applied to an inverter output waveform. With this arrangement, even when the inverter apparatus is disconnected from an AC power system in a state in which a power factor of a load impedance is proximate to one, a frequency variation is generated in an inverter output, thereby ensuring detection of the islanding operation.

Inverter apparatus islanding operation detecting method and inverter apparatus capable of surely detecting an islanding operation with a simple construction

PROBLEM TO BE SOLVED: To attain improvement of system power generation efficiency by independently performing maximum power follow-up relating to each solar battery array, in a system interconnection inverter connecting in parallel a plurality of the solar battery arrays input. SOLUTION: In the power conversion apparatus for solar power generations with a plurality of solar battery modules 8a, 8b, 8c serving as the power source, boost chopper parts 26a, 26b, 26c for performing maximum power follow-up of each solar battery module 8a, 8b, 8c for every thereof and a DC/DC converter of waveform forming parts 34a, 34b, 34c, 34d, etc. are provided, maximum power is led through from each solar battery module 8a, 8b, 8c thereafter to be collectively converted into an AC output by an inverter 23, a DC/AC converter 36, etc. COPYRIGHT: (C)2004,JPO&NCIPI

Masaki Eguchi

Papers

Inverter control method and inverter apparatus using the method

Power supply system for distributed source

Power conversion device for photovoltaic generation

Inverter apparatus islanding operation detecting method and inverter apparatus capable of surely detecting an islanding operation with a simple construction

Power conversion apparatus for solar power generation