摘要:
The subject matter of the present invention is a method for monitoring a photovoltaic generator (1) for generating current with a number of solar cells connected between two external connections by repeated feeding of a current with a frequency spectrum into the generator current circuit, detecting thereby a respective frequency response in the frequency spectrum with the supplied current as the input variable and an electric variable of the generator as the output variable, and detecting a change in the frequency response for monitoring the photovoltaic generator (1) in the event of a change during repeated feeding.
摘要:
The subject matter of the present invention is a method for monitoring a photovoltaic generator (1) for generating current with a number of solar cells connected between two external connections by repeated feeding of a current with a frequency spectrum into the generator current circuit, detecting thereby a respective frequency response in the frequency spectrum with the supplied current as the input variable and an electric variable of the generator as the output variable, and detecting a change in the frequency response for monitoring the photovoltaic generator (1) in the event of a change during repeated feeding.
摘要:
A method of activating a Multi-String inverter for photovoltaic generators (1a, 1b) of a photovoltaic plant (6), the Multi-String inverter incorporating on the input side a separate DC-DC converter (2a, 2b) for each generator string (photovoltaic generator) (1a, 1b) and each output of the DC-DC converters (2a, 2b) being connected in parallel and to an input of a DC-AC converter (3) and the DC-AC converter (3) being connected with an alternating current mains (4) for feeding into the mains aims at improving efficiency. This is achieved in that one or several electrical variables, namely input current, input voltage and/or input power are measured at each DC-DC converter (2a, 2b) and at least one of the DC-DC converters (2a, 2b) changing its operating condition as a is function of this measurement when a limit value and/or a range is exceeded in such a manner that its power loss is reduced so that the energy yield of the photovoltaic plant (6) is increased.
摘要:
A method of activating a Multi-String inverter for photovoltaic generators (1a, 1b) of a photovoltaic plant (6), the Multi-String inverter incorporating on the input side a separate DC-DC converter (2a, 2b) for each generator string (photovoltaic generator) (1a, 1b) and each output of the DC-DC converters (2a, 2b) being connected in parallel and to an input of a DC-AC converter (3) and the DC-AC converter (3) being connected with an alternating current mains (4) for feeding into the mains aims at improving efficiency. This is achieved in that one or several electrical variables, namely input current, input voltage and/or input power are measured at each DC-DC converter (2a, 2b) and at least one of the DC-DC converters (2a, 2b) changing its operating condition as a function of this measurement when a limit value and/or a range is exceeded in such a manner that its power loss is reduced so that the energy yield of the photovoltaic plant (6) is increased.
摘要:
An inverter has two input lines; an inverter bridge connected between the input lines and including at least one half-bridge having two normally conductive gate-controlled semiconductor switches; a controller which supplies control voltages to the gates of the semiconductor switches in an operative state of the inverter; and a DC voltage source for supplying an auxiliary control voltage to the gates of the semiconductor switches in an inoperative state of the inverter so as to hold the inverter bridge in a non-conductive state between the input lines. The DC voltage source has a charging unit connected between the input lines in series with a further normally conductive gate-controlled semiconductor switch, and charging a storage unit for electric charge, which is connected to the gate of the further semiconductor switch such that this switch becomes non-conductive, when the storage unit has been sufficiently charged for providing the auxiliary control voltage.
摘要:
An inverter comprises two input lines; an inverter bridge connected between the input lines and including at least one half-bridge comprising two normally conductive gate-controlled semiconductor switches; a controller which supplies control voltages to the gates of the semiconductor switches in an operative state of the inverter; and a DC voltage source for supplying an auxiliary control voltage to the gates of the semiconductor switches in an inoperative state of the inverter so as to hold the inverter bridge in a non-conductive state between the input lines. The DC voltage source has a charging unit connected between the input lines in series with a further normally conductive gate-controlled semiconductor switch, o and charging a storage unit for electric charge, which is connected to the gate of the further semiconductor switch such that this switch becomes non-conductive, when the storage unit has been sufficiently charged for providing the auxiliary control voltage.
摘要:
An inverter is devised to avoid high-frequency voltages at input terminals and to allow good efficiency thanks to its simple and cost-optimized circuit layout. This is achieved by a method of converting a direct current voltage, more specifically from a photovoltaic source of direct current voltage, into an alternating current voltage at a frequency through a bridge circuit comprising switching elements (V1-V4) and free-wheeling elements (D1-D4), said switching elements (V1-V4) being on the one side gated at the frequency and on the other side clocked at a high clock rate, a direct current voltage circuit, an alternating current voltage circuit and a plurality of free-wheeling phases being provided. It is provided that, during the free-wheeling phases, the alternating current voltage circuit is decoupled from the direct current voltage circuit by means of a switching element disposed in the direct current voltage circuit, a free-wheeling current flowing through one of the free-wheeling elements (D1) in the bridge circuit when in the decoupled state.
摘要:
A method of converting a direct voltage generated by a decentralized power supply system into three-phase alternating voltage by means of a plurality of single-phase inverters (WR1-WR3), said alternating voltage being provided for supplying an electric mains, is intended to avoid inadmissible load unbalances using single-phase inverters. This is achieved in that, upon failure of one inverter (WR1-WR3), an asymmetrical power supply distribution is reduced by limiting the output of the other inverters. The method makes it possible to simplify three-phase voltage monitoring.
摘要:
The invention relates to a photovoltaic system for feeding three-phase current to a power grid that includes several monophase or three-phase photovoltaic inverters that can be connected to the power grid at the output end and are each fitted with a disconnecting device at the output end. The system includes several photovoltaic generators that are connected to the input end of the photovoltaic inverters. A central control and monitoring unit is connected between the photovoltaic inverters and the power grid. The control and monitoring unit has a grid monitoring device at the feeding point to the grid to measure one or more grid parameters. At least one communication link is provided between the individual photovoltaic inverters or the individual disconnecting devices and the connected central control and monitoring unit such that the connecting devices can disconnect the individual photovoltaic inverters from the power grid by means of a control instruction signal of the communication link. The central control and monitoring unit includes a load unbalance recognition component and a load unbalance regulation component, wherein the regulation includes limiting the power variation between the individual phases to a predetermined value.
摘要:
The subject matter of the invention is an inverter (1), comprising a casing (8) as well as at least one casing cover (2), said casing cover (2) being mechanically engaged with a safety plug (10), said safety plug (10) being in electrical connection with at least the one load-current circuit located on the DC side, the inverter being switched off or disconnected at least from the DC-side load-current circuit after removal of the safety plug from the casing (8).