摘要:
A method for switching on and off electric current includes detecting a verification condition, switching on the electric current responsive to the detected verification condition, establishing a communication via a communication network after switching on the electric current, detecting a switch-off condition via the established communication, and switching off the electric current responsive to the detected switch-off condition. An apparatus and a system are described for controlling switching on and off electric current.
摘要:
Intelligent safety disconnect switching methods and arrangements for PhotoVoltaic (PV) panels are disclosed. A switching device that is connected between a PV panel and a PV panel string detects a low current condition or an arc fault condition in the PV panel string. The switching device is automatically controlled to disconnect thePV panel from the PV panel string responsive to detection of the low current condition or the arc fault condition. Switching device control could also be responsive to a disconnect command. For example, such a command could be generated by a grid sensor responsive to determining that an inverter, to which the PV panel string is connected, is not connected to an electrical grid.
摘要:
Methods, systems, and devices for determining current are described herein. One method includes receiving power from a current conductor using a first quantity of coils of a wire around a magnetic core at least partially surrounding a portion of the current conductor, receiving an indication associated with a determined current through the current conductor from a current sensor associated with the wire, and receiving power from the current conductor using a second quantity of the coils of the wire, wherein the second quantity is determined based, at least in part, on the determined current.
摘要:
A device includes a connection receiving power from a power source under normal conditions and circuitry configured to determine, based on an input from the connection, when the power from the power source is absent; output, when the power source is absent, a test signal at the connection; and generate a detection signal based on current flow generated following the output of the test signal, wherein the detection signal indicates a position of a switch connecting the circuitry to the connection and the generated detection signal indicates the switch is closed when the current flow is above a threshold. The circuitry is configured such that when the power from the power source is absent, the switch is dosed, and plural devices are connected on the supply side of the switch, the plurality of devices on the supply side appear as a substantially open circuit to the test signal.
摘要:
Methods and systems for detecting a falling power line in a power transmission or distribution system are described. Electrical measurements at various points in the power distribution system are used to detect changes in a power line indicating that the conductor has broken or become disconnected. Upon detection, control mechanisms are used to deenergize the conductor while the conductor is falling and/or before it contacts the ground.
摘要:
Power supply current is supplied to a plurality of electric loads, the power supply current being generated by a DC power supply, flowing in and branching from a shared power supply switching device and then flowing in reverse connection protection devices that are a field-effect transistor and connected in series to the electric loads, respectively. The reverse connection protection devices are connected in a polarity such that the power supply current flows in the forward direction of parasitic diodes generated between the source terminal S and the drain terminal D of the field-effect transistor. When the current in the field-effect transistor is less than a predetermined value, a gate control circuit interrupts the gate voltage of the reverse connection protection device to cause the reverse connection protection device to open.
摘要:
A power saving circuit for an electronic device is disclosed. The power saving circuit includes a direct-current (DC) power supply, a sensing unit, and a control unit. The DC power supply is used for providing a DC current. The sensing unit, coupled to the DC power supply, is used for detecting the DC current and operating to generate a voltage signal according to the DC current. The control unit, coupled to the sensing unit, is used for determining whether a system circuit of the electronic device has a light load or a heavy load and generating an enable signal.
摘要:
Various techniques are employed alone or in combination, to reduce the levelized cost of energy imposed by a power plant system. Solar energy concentrators in the form of inflated reflectors, focus light onto photovoltaic receivers. Multiple concentrators are grouped into a series-connected cluster that shares control circuitry and support structure. Individual concentrators are maintained at their maximum power point via balance controllers that control the flow of current that shunts this series connection. DC current from clusters is transmitted moderate distances to a centralized inverter. The inductance of transmission lines is maximized using an air-spaced twisted pair, enhancing the performance of boost-type three phase inverters. Cluster outputs are separate from individual inverters in massively interleaved arrays co-located at a central location. Step-up transformers convert inverter voltages to grid voltages, and small transformers provide isolation and voltage step-up only on receiver-to-receiver imbalance currents, typically
摘要:
A device includes a connection receiving power from a power source under normal conditions and circuitry configured to determine, based on an input from the connection, when the power from the power source is absent; output, when the power source is absent, a test signal at the connection; and generate a detection signal based on current flow generated following the output of the test signal, wherein the detection signal indicates a position of a switch connecting the circuitry to the connection and the generated detection signal indicates the switch is closed when the current flow is above a threshold. The circuitry is configured such that when the power from the power source is absent, the switch is closed, and plural devices are connected on the supply side of the switch, the plurality of devices on the supply side appear as a substantially open circuit to the test signal.
摘要:
A light load current detection system including a detection process module and a control circuit is provided for detecting a current value of a light load current of a load in a light load mode; the detection process module including a power save unit and a voltage detection module. The power save unit sends a power save signal, wherein a cycle of the power save signal corresponds to a switch state. The voltage detection module detects an input voltage value to generate and output a detection signal. The control circuit includes a data table and a threshold, the data table showing a relation among the cycle, the current value and the input voltage value. The control circuit determines if the current value reaching the threshold, the switch is turned off in the light load module.