A method and apparatus for converting DC input power to AC output power. The apparatus comprises means for storing energy from a DC input current, means for converting the DC input current to AC output current, means for causing the energy to be stored in and drawn from the means for storing during at least one storage and at least one burst period, respectively, the AC output current greater than the DC input current during the at least one burst period; a first means for determining a maximum power point (MPP) and operating the means for converting proximate the MPP; and a second means for determining a difference in a first and a second power measurement, producing an error signal indicative of the difference, and coupling the error signal to the first means to adjust at least one operating parameter of the means for converting to drive toward the MPP.

Method and apparatus for improved burst mode during power conversion

PROBLEM TO BE SOLVED: To provide a power conversion device for outputting power generated from power supply to an alternating current system which can improve operation continuity when voltage of the alternating current system lowersSOLUTION: The power conversion device has: a power converter 11 whose one end is connected to an alternating current system 2 and the other end is connected to a power supply 3 to control power generated from a power generator; power converter 10 which controls power to be outputted to the alternating current system; and a control part 200 which controls the power converter Voltage from the alternating current system is calculated by an amplitude calculation device 2001, the calculated voltage amplitude is converted to electric current, and the upper limit of the power generated from the power supply 3 is limited by a limiter 2005 A maximum power operation controller 2004 inputs direct current and panel voltage and searches for a current instruction value Idcref at which the maximum power operation can be performed The current instruction value Idcref is limited to the value between 0 and the upper limit (IdcrefN), a difference with the direct current is obtained, and a voltage instruction value Vchop is generated by a current controller 2007 to output to the power converter 11

Power conversion device and power generation conversion system

PROBLEM TO BE SOLVED: To make it possible to recognize the presence or absence of a failure with system interconnection disconnected. SOLUTION: A power conditioner device 4 includes: an inverter circuit 14 that has multiple switching arms 21, 22 each constructed of pair of switching elements and converts direct-current power from a dispersed power system 2 into the alternating-current power of a commercial system 3; a drive control circuit 18 for controlling driving of the switching elements; and an interconnection relay circuit 16 that disconnects system interconnection. The power conditioner device is provided with a voltage drop determination unit 32 and a control circuit 40. When a first diagnosis activation signal is detected, all the switching elements are turned off with the system interconnection disconnected. Thereafter, only one of the switching elements in off state is turned on and this switch-on operation is sequentially performed. The voltage drop determination unit determines whether or not the input voltage of the inverter circuit has dropped each time this switch-on operation is performed. When the voltage drop determination unit determines that the input voltage has dropped, the control circuit causes a display unit 17 to display a warning about short circuit failure. COPYRIGHT: (C)2008,JPO&INPIT

Power conditioner device

PROBLEM TO BE SOLVED: To detect a ground fault in solar batteries with use of inexpensive components. SOLUTION: When a first converter 14a is started, a first switch 23a is closed and further second and third switches 23b and 23c are opened by control through first to third converter control portions 19a to 19c. If the positive pole of a first solar battery 12a is electrically connected to the ground, the following takes place: when the first switch 23a is closed, the positive pole and the negative pole of the first solar battery 12a are short-circuited to each other, and the direct-current voltage Vin of the first solar battery 12a drops. If the positive pole of the first solar battery 12a is not electrically connected to the ground, the following takes place: when the first switch 23a is closed, the direct-current voltage Vin of the first solar battery 12a does not drop. Therefore, the first converter control portion 19a monitors the direct-current voltage Vin of the first solar battery 12a. If the direct-current voltage Vin of the first solar battery 12a drops when the first switch 23a is closed, the first converter control portion 19a judges that the positive pole of the first solar battery 12a is electrically connected to the ground. COPYRIGHT: (C)2004,JPO&NCIPI

System cooperation inverter arrangement

PROBLEM TO BE SOLVED: To make an output effective power recovered to a state just before occurrence of a brownout, promptly in the case where an electric power system is recovered normally from the brownoutSOLUTION: A power conditioner comprises: a brownout detection part 4 which monitors an internal DC voltage Vdc, and switches an operation mode to a brownout mode by deciding that a momentary voltage drop phenomenon of an electric power system 11 has occurred in the case where the voltage Vdc exceeds an upper limit set in advance, and returns the operation mode to a normal mode by deciding that the momentary voltage drop phenomenon has been restored to the normal state in the case where the voltage Vdc falls short of a lower limit set in advance; an inverter control part 9 which operates an inverter circuit 13 so that an output current iac is in agreement with a value just before the occurrence of the momentary voltage drop phenomenon or a movement average value thereof in the brownout mode; a boosting-up chopper control part 14 which changes a DC input current iin so that the voltage Vdc is in agreement with a target value set in advance in the brownout mode; and a maximum power following control part 6 which returns a current change command of the DC input current iin to a command just before the occurrence of the momentary voltage drop phenomenon in the case where the operation mode has been returned to the normal mode from the brownout mode

Operation stabilization method of power conditioner at time of brownout recovery, power conditioner carrying out the same, and program for operation stabilization of power conditioner at time of brownout recovery

PROBLEM TO BE SOLVED: To allow utilizing an inverter for a single-phase two-wire 200 V output widely used in a market to link a photovoltaic power generating system to a single-phase 100 V system in a solar power generation system. SOLUTION: The inverter 8 is not isolated between an input and an output, and converts power from a solar cell 1 into AC power of a single-phase three- wire 200 V. A transformer 10 connects lines from the single-phase three-wire 200 V with a single-phase two-wire 100 V system 4 in which one wire is grounded. A neutral point potential wire of the single-phase three-wire 200 V is connected with the grounded wire of the system 4 so that a line-to-ground fault detecting sensor 89 built in the inverter 8, can operate. COPYRIGHT: (C)2002,JPO

System linking apparatus and method for linking

PROBLEM TO BE SOLVED: To preclude a problem in a solar power generating system having an inverter that, if the filter capacitor of the inverter is deteriorated, loss of its generated energy is unavoidable because the inverter operation is interrupted. SOLUTION: If a deterioration judging part 211 judges that the capacitor 24 is deteriorated, the operation of the inverter 2 is continued while suppressing the output current of the inverter 2 by an output suppressing part 212. The deterioration of the capacitor is alarmed by an alarm part 213. COPYRIGHT: (C)2002,JPO

Power converter and its control method, and power generating system

PROBLEM TO BE SOLVED: To provide at a low price a system which is excellent in capability for high-speed detection, has a narrow undetectable region, and is capable of detecting service interruption of a system without being accompanied with large variation of effective power, etc., on a DC power source side, without lowering system efficiency. SOLUTION: This is a system interconnection inverter unit 7 provided with an inverter portion 4 which converts inputted DC power into AC power and outputs it, and a controlling means 3, 10, 11 which controls the input voltage of the inverter portion to a constant value. The inverter unit 7 is fitted with a service interruption judging means for a system 5, 6, 10 which detects the variation of the output voltage or output current of the inverter portion which is generated owing to control by the controlling means, when service interruption to the system 9 occurs, and judges whether or not service interruption to the system occurs.

System interconnection inverter unit, system interconnection power system, photovoltaic power generation system and method for detecting service interruption of system

PROBLEM TO BE SOLVED: To dispense with a master slave cable even when performing parallel operations in a plurality of units, and to reduce the cost, and improve the workability of installation, and enhance flexibility. SOLUTION: In a power converter 2 which converts DC power outputted from a solar cell module 1 into AC power and outputs it to a system power source 4, a plurality of ripple generation means 231-23X, which detect single operations in the condition of the supply of power from the system power source being stopped severally according to different active systems when detecting the single operations, are provided, and a selection means 24 selects and operates one or more ripple generation means from among the plurality of ripple generation means. COPYRIGHT: (C)2003,JPO

Power converter, power conversion system, and method of detecting single operation

PROBLEM TO BE SOLVED: To detect DC earth without stopping the operation of an inverter even in a portion where a DC ground voltage is zero or near zero in a DC power supply such as a solar battery. SOLUTION: A power conversion system has a DC power supply, where DC ground voltage is substantially fixed, having a designated ground stray capacitance and outputting DC power, with a power conversion means converting the DC power output from the DC power supply to AC power by switching. The phase of DC ground voltage produced in the DC power supply by switching is detected (ST102), the phase of AC earth current flowing through the ground stray capacitance and the earth resistance of the DC power supply is detected (ST03), and a difference between two detected phases is compared with a designated threshold, thereby determining DC earth of the DC power supply (ST08).

正毅鈴井

Papers

System linking apparatus and method for linking

Power converter and its control method, and power generating system

System interconnection inverter unit, system interconnection power system, photovoltaic power generation system and method for detecting service interruption of system

Power converter, power conversion system, and method of detecting single operation

Earth detection method and device in power conversion system

正毅 鈴井

Papers

System linking apparatus and method for linking

Power converter and its control method, and power generating system

System interconnection inverter unit, system interconnection power system, photovoltaic power generation system and method for detecting service interruption of system

Power converter, power conversion system, and method of detecting single operation

Earth detection method and device in power conversion system

正毅鈴井