An electric power tool includes: a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation.

Electric power tool

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 monitoring system and method for monitoring performance of individual powers sources in a distributed power source system A monitoring module is coupled to each of the power sources, or to each string of serially connected power sources, to monitor and collect data regarding current, voltage, temperature and other environmental factors at the power source The collected data is transmitted over a power line to a central analysis station for analysis Data collected from each source indicates malfunction or degradation at the source Comparison of data collected from adjacent sources filters for environmental factors impacting neighboring sources such as cloudy days for a solar panel Comparison of data collected from the same source at different times indicates soiling or degradation of the source with time or periodic events such as a moving shade from an adjacent building

Monitoring of Distributed Power Harvesting Systems Using DC Power Sources

Method for distributed power harvesting using DC power sources

An energy storage system and a method of controlling the same is provided. The energy storage system may directly provide generated DC power or DC power stored in a battery to a DC load without performing a DC/AC conversion or an AC/DC conversion. Furthermore, in the case where a grid operates abnormally (e.g. power interruption) and the energy storage system functions as an uninterruptible power supply (UPS), power stored in a battery may be selectively provided to loads according to power remaining in a battery, and thus stored power may be used stably.

Energy storage system and method of controlling the same

PROBLEM TO BE SOLVED: To make a solar light power generator compact, to prevent the non- synchronized operation of each dispersed power supply at the same time and to improve the performance by connecting respective power converters to one common controller, and operating the respective power converters in synchronization under the control of the controller. SOLUTION: The operation of inverters (power converters) 24 of respective dispersed power supplies 22a-22d is centrally controlled by one common controller 21 provided in a factory, a building control station or the like. The controller 21 and a system-linkage protecting relay 25 are connected by an optical fiber 26, which transmits the detected signals for over-voltages, insufficient voltages and the like of this relay, 25. The system-linkage protecting relay 25 is commonly used, and the linkage protection of the respective dispersed power supplies 22a-22d is performed. The controller 21 and the respective dispersed power supplies 22a-22d are connected through optical cables 27a and 27b. The controller 21 and a battery power supply 23 are connected through optical cables 28a and 28b. The information is imparted and received among the controller 21, each inverter 24 and the battery power supply 23. COPYRIGHT: (C)1998,JPO

Solarlight power generator

PROBLEM TO BE SOLVED: To perform a coordinated operation and an independent operation by preventing a DC voltage from being applied to the side of a power system with an economical configuration for utilizing the power-feeding path of the three-phase AC power of the coordinated operation for feeding DC between power-converting devices SOLUTION: A distributed power supply system is provided with a first power- converting device 18 for converting a DC power supply (a solar cell 16) to the three- phase AC power of coordinated operation when a system is normal and for taking out a DC power from the DC power supply when the system fails, an AC power-feeding path 22 for feeding three-phase output to the power system side via a switcher circuit part 23 when the system of the device 18 is normal, a first DC power-feeding line 31N that is connected to either of the DC passage paths 18P and 18N of the device 18 directly, a DC power-feeding path 31 that is formed by two wires of a single-phase line 22V of the power-feeding path 22 and a second DC power-feeding line 31P that is connected to the other of the passage paths 18P and 18N via a switching element in the device 18, and a second power-converting device 30 for converting a DC power that is supplied from the device 18 via the power-feeding path 31 to an independent three-phase AC power when the system fails and for feeding it to a load 26

Distributed power supply system

PURPOSE:To make the power generation capacity of a solar battery maximum, and to effectively utilize solar radiation energy by operating a DC/DC converter and controlling the output voltage of the solar battery so that the generated power of the solar battery becomes maximum. CONSTITUTION:At the time of supplying electric power from a solar battery 1 to an inverter 3, a DC/DC converter 5 controls an output voltage of the solar battery 1 so that the generated electric power of the solar battery 1 becomes maximum. When the generatable maximum electric power PPVL of the solar battery 1 is smaller than the consumption electric power PINV of the inverter 3, insufficient electric power obtained by subtracting the generated electric power PPVI of the solar battery from the consumption electric power PINV of the inverter 3 is supplied by electric power supply caused by discharge of a battery 4. On the other hand, when the generatable maximum electric power PPVI of the solar battery 1 is larger than the consumption electric power PINV of the inverter 3, surplus electric power obtained by subtracting the consumption electric power PINV of the inverter 3 from the generated electric power PPVI of the solar battery 1 is used for the charging of the battery 4.

Photovoltaic power generating equipment capable of jointly using battery

PROBLEM TO BE SOLVED: To provide a power storage type photovoltaic power generation system capable of specifying the power generated by a solar cell and the discharge power of a power storage device, and preventing reverse flow of the discharged power of the power storage device charged with the power from a grid. SOLUTION: A power conditioner of the photovoltaic power generation system in which a solar cell is linked to a grid is provided with: a power converter having both functions of an inverter operation of converting DC power from the solar cell into AC and a converter operation of converting AC power from the grid into DC; a reverse flow relay for detecting that reverse flow is generated in the grid; a single controller for selectively controlling charging/discharging of power for any one of a first power storage device suppressing output variation of the solar cell and a second power storage device charging midnight power; and a changeover switch for interrupting connection between the second power storage device and the controller on the basis of an output of the reverse flow relay when reverse flow of excessive power occurs in the solar cell. In the power conditioner, the controller is connected to a solar cell side of the power converter, and the changeover switch is inserted and connected between the first power storage device, the second power storage device and the power converter. COPYRIGHT: (C)2009,JPO&INPIT

Power storage type photovoltaic power generation system

PROBLEM TO BE SOLVED: To save the installation space of a distributed power supply type solar beam power generation system while reducing the cost and the work miss by housing a solar cell connecting circuit section and a current collecting circuit section having a stationary power converter in respective current collecting boxes. SOLUTION: Since the state, power generation, and the like, of distributed power supplies 2a-2d are displayed on a controller 23 for each operation, operating condition of the distributed power supplies 2a-2d can be monitored centrally at one monitoring station in factory or building and the operation control can be carried out efficiently. A current collection box 16 is disposed in the vicinity of the solar battery 3 of each distributed power supply 2a-2d and the installation space can be saved since the solar cell connecting circuit section and a current collecting circuit section having an inverter, conventionally housed individually in two machine containing boxes, are housed collectively in one current collection box 16. Furthermore, installation cost can be reduced while preventing the wiring miss because connection between a current collecting box and an inverter housing box is not required in the field. COPYRIGHT: (C)1998,JPO

満松川

Papers

Solarlight power generator

Distributed power supply system

Photovoltaic power generating equipment capable of jointly using battery

Power storage type photovoltaic power generation system

Solar beam power generation system

満 松川

Papers

Solarlight power generator

Distributed power supply system

Photovoltaic power generating equipment capable of jointly using battery

Power storage type photovoltaic power generation system

Solar beam power generation system

満松川