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 has a reduced number of capacitors for storing energy such as renewable energy, thereby reducing cost and improving stability of the system. The energy storage system is configured to store power from a power generating unit, and includes: a storage capacitor having a first end electrically coupled to one end of the power generating unit; a secondary battery having a first terminal electrically coupled to a second end of the storage capacitor, and a second terminal electrically coupled to another end of the power generating unit; and a first converter configured to selectively couple the storage capacitor and the secondary battery to a load.

Energy storage system

This invention is generally concerned with power supply circuits, and more particularly, with circuits to supply power to a mains supply, such as domestic grid mains, from a photovoltaic device. A photovoltaic power conditioning circuit for providing power from a photovoltaic device to an alternating current mains power supply line, the circuit comprising: a DC input to receive DC power from said photovoltaic device; an AC output configured for direct connection to said AC mains power supply line; a DC-to-AC converter coupled to said DC input and to said AC output to convert DC power from said photovoltaic device to AC power for output onto said power supply line; and an electronic controller directly coupled to said power supply line to measure a voltage of said power supply line and a current in said supply line and to control said DC-to-AC converter responsive to said measuring.

Power supply circuits

PROBLEM TO BE SOLVED: To provide a photovoltaic power generation system with easy installation work and high efficiency. SOLUTION: In this photovoltaic power generation system, an inverter controller 6 controls an inverter circuit 5 for maximum power point following-up operation during the period where the output voltage of a booster circuit 11 is kept constant by a booster unit controller 9. The booster unit controller 9 controls the booster circuit 11 for maximum power point following-up operation during the period where the input voltage of the inverter circuit 5 is kept constant by the inverter controller 6. Thus, manual setting of the boosting ratio of the booster circuit 11 can be eliminated at the time of system installation.

Booster unit, power conditioner, and photovoltaic power generation system

PURPOSE:To always take out a maximum power from a DC power source by satisfactorily performing the maximum power point tracking control regardless of the variance in voltage-current characteristic of the DC power source like a solar battery. CONSTITUTION:A CPU 48 outputs the waveform pattern read out from a ROM 49 to a D/A converter 51 to obtain a reference sine wave signal S11 and switches an FET bridge 36 through a PWM modulation circuit 43 and a gate drive circuit 42 to convert the DC power from a solar battery 32 to an AC power. A detected inverter output current IOUT is converted to a digital value by an A/D converter 47 and stored in a RAM 50. The CPU 48 compares the preceding output current value and the present, output current value with each other to discriminate whether the output current IOUT is increased or not. The amplitude changing direction of the reference sine wave signal S11 is kept if it is increased, but this direction is inverted if it is reduced, and the amplitude of the reference sine wave signal S11 is changed in the determined direction by one stage to perform the maximum power point tracking control of the solar battery 32.

System interconnection type inverter controller

PURPOSE: To improve the responsiveness of current control with simple circuit constitution by detection the fluctuation of inverter input (solar battery output) accompanying the increase/decrease of an output current and performing solar battery maximum point following control. CONSTITUTION: This system interconnection inverter 1 is inserted between a solar battery 2 and a commercial power source 3. A current signal IT on the primary side of a high frequency transformer 6 which is the actual value of a controlled variable is detected in a current detector 17 and inputted to a hysterisis comparator 13 along with a current command signal 18 outputted from a signal processing arithmetic circuit 12. When the current signal IT exceeds the upper limit set value of the current command signal 18, the switching elements Q1 and Q4 of a high frequency inverter bridge 5 are turned OFF, the switching elements Q2 and Q3 are turned ON and a current grade is controlled so as to be in a decreasing direction. Also, when the current signal IT decreases and becomes less than a lower limit set value, the elements Q1 and Q4 are turned ON, the elements Q2 and Q3 are turned OFF and control is performed so as to increase the current signal IT. COPYRIGHT: (C)1995,JPO

System interconnection type inverter

PROBLEM TO BE SOLVED: To provide an inverter device and a control method thereof which can prevent the chattering phenomenon of a linking switch with only the input voltage of an inverter device monitored and whose output can be drawn effectively without being wasted at the time of the low output of a solar battery, by preventing inrush current from flowing into an inverter device from a commercial system, when the output of a solar battery is not sufficient. SOLUTION: A diode 6 is formed between a system power source 3 and a DC capacitor 5, so that the inrush current does not flow into an inverter device 1 from the system power source 3. In order to draw as much output as possible, even if the output of a solar battery 2 decreases, when inverter input voltage reaches its minimum input voltage value, the inverter input voltage is controlled so as not to become lower than the minimum input voltage by conducting such control as the operating voltage of the solar battery 2 may be shifted from a voltage value at the maximum point to the open voltage side of the solar battery, or in such a direction so as to become higher.

Inverter device and starting thereof

PROBLEM TO BE SOLVED: To easily and efficiently link a photovoltaic power generation system provided with plural solar cell strings having different output voltages to a commercial power system. SOLUTION: In a solar cell system for linking plural solar cell strings 1a and 1b, with which plural solar cell modules are serially connected, through a power conditioner 3 to a commercial power system 4, on the pre-stage of the power conditioner 3, a boosting unit 2 is provided for increasing the non-standard output voltage of the non-standard solar cell string 1b to the standard output voltage of the standard solar cell string 1a when parallel connecting the standard solar cell string 1a provided with serial standard modules and the non-standard solar cell string 1b provided with modules less than the number of these serial standard modules to the power conditioner 3.

司竹林

Papers

Booster unit, power conditioner, and photovoltaic power generation system

System interconnection type inverter controller

System interconnection type inverter

Inverter device and starting thereof

Photovoltaic power generation system and boosting unit to be used therefor

司 竹林

Papers

Booster unit, power conditioner, and photovoltaic power generation system

System interconnection type inverter controller

System interconnection type inverter

Inverter device and starting thereof

Photovoltaic power generation system and boosting unit to be used therefor

司竹林