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

In a power supply system (10) having a cogeneration unit (12) equipped with an internal combustion engine (12a) and a generator (12b) to generate power to be supplied to a power destination and hot water to be supplied to a hot water destination, there are provided with a natural energy generation unit (14) that generates power with natural energy, a power supply unit (20) that receives the power generated by the generator and natural energy generation unit to supply the received power to the power destination; a voltage detector (22a) that detects voltage (V1) of the power flowing through an connecting bus (22), and an electric heater (12l). The power supply unit (20) controls operation of the electric heater based on the detected connecting bus power voltage (V1), thereby effectively utilizing surplus electricity without transmitting back it to a commercial power source.

Power supply system

The present invention is applied to a photovoltaic power generation system 1 comprising a solar battery system 2 provided with a plurality of solar battery modules 6 disposed in series and in parallel, a connection box 3, and a power conditioner 4 for converting a direct-current power PX into an alternate power synchronizing with a frequency (50Hz /60Hz) on a system side (commercial power supply) and an alternate voltage. In a state where the photovoltaic power generation system 1 is actually installed, a DC current IX - direct-current voltage VX curve or a direct-current power PX - direct-current voltage VX curve is displayed on a screen so as to measure if the solar battery system 2 supplied to the power conditioner 4 is in a normal state or an abnormal state.

Power conditioner comprising curve tracer and curve evaluating method for curve tracer

PROBLEM TO BE SOLVED: To minimize the drop of power factor to be caused by a load and the effect to be caused by higher harmonics on a system side, and also to make it possible for a system to be automatically changed over to a self-supporting operation if a system power source is in trouble. SOLUTION: The system voltage and current of a system side are fed back from a load 5 to a power conditioner 21, to control power factor and the suppression of higher harmonics. Also, the abnormality of a system power source 4 is detected, based on the voltage of the system. If there is any abnormality, an electromagnetic contactor 22 is automatically opened, while a relay 14 is automatically closed to change over to an operation supported by non-utility power supply. When the system power source 4 restores its normal condition, the electromagnetic contactor 22 is automatically closed and the relay 14 is opened to change over to an interconnected operation.

Power conditioner and dispersed power supplying system

PROBLEM TO BE SOLVED: To eliminate nonuniformity in output among power conditioners by detecting an inverse flow of a current in the all power conditioners when a plurality of power conditioners are connected to a commercial power supply system. SOLUTION: A plurality of power conditioners 10-1, 10-2,..., 10-n are connected using a wired system or radio system parallel communication link 22 for the exchange of an output power quantity, fault information, an synchronization signal of a single operation and an operating condition or the like of each power conditioner 10-1, 10-2,..., 10-n. Moreover, a reverse flow of the current is monitored by one unit of the power conditioner 10-1 and obtained information is then transmitted to the power conditioners 10-2,..., 10-n so that the quantity of power generation is controlled to prevent the inverse flow of the current on the basis of pieces of the obtained information.

Operation control device and control method of power conditioner

An apparatus for controlling the operation of power conditioners (10) for supplying the generated power to an external power system such as a commercial power system, in which power conditioners (10) are interconnected to an external power system such as a commercial power system, the power conditioners (10) are interconnected through information exchange means, at least one of the power conditioners (10) monitors the reverse power flow, and the power conditioners (10) exchange the monitor information with information of the other power conditioners (10), thereby equalising the outputs of all the power conditioners (10). A generator (42) has armature windings (60), and an inverter circuit (13) of the power conditioner (10) provided for each of the armature windings (60) is controlled by cable or radio.

Power system having generator driven by engine

PROBLEM TO BE SOLVED: To provide a highly practical circuit protective device that can be applicable to the change of a capacitive load and a resistive load, that controls an inrush current or a short circuit current with a constant current, that drives the capacitive load without interrupting power supply to the load, and that does not affect the drive of other loads, by interrupting a current after supplying the constant current to the short circuit load for a prescribed period of time. SOLUTION: The circuit protective device is made up of a branching/controlling means 2, which controls the operation of an entire device, and output branching means 3, which are provided with a constant current portion 12, an interruption portion 13, an instantaneous interruption portion 14, a current detection portion 15, and an operation/interruption drive portion 16. COPYRIGHT: (C)2007,JPO&INPIT

Nobuyuki Toyoura

Papers

Power conditioner comprising curve tracer and curve evaluating method for curve tracer

Power conditioner and dispersed power supplying system

Operation control device and control method of power conditioner

Power system having generator driven by engine

Circuit protective device and method of interrupting short circuit current method