Techniques for duplex communication and power transfer across an isolator are provided. In an example, a first transceiver coupled to a first side of an isolator can include a transmit modulator configured to receive first data and timing signals, to provide control signals to oscillate an output of the transceiver to transmit power and to order each half-cycle of an oscillation cycle of the output to transmit the first data. A second transceiver coupled to a second side of the isolator can include a receive detection circuit configured to compare a received oscillation cycle with a plurality of thresholds and to provide a plurality of comparator outputs indicative of reception of the positive half-cycle and the negative half-cycle, and a receive decoder configured to identify the order of half-cycles and to provide an output indicative of logic level of the first data.

Provided is a communication device using a powerline which can transmit and receive control data and so on by using the powerline, and an LED (Light Emitting Diode) lighting system using the device which can control the illumination of an LED by using the communication device. The LED illumination device comprising: one or more control devices coupled with commercial power source through powerlines; one or more LED illumination devices coupled with control devices, respectively, through the powerlines; and a management device for performing communication with the control devices; wherein the control devices and the LED illumination device perform data transmission and reception by using the powerlines, the data communication from the control devices to the LED illumination device is executed by broadcasting method, and the data communication from the LED illumination device to the control devices is executed by polling method.

A method for direct current power line communication in a photovoltaic system includes (a) transferring power between a photovoltaic device and a load using a power line, (b) detecting a change in operation of the power line, and (c) in response to the detected change in operation of the power line, decoding operating state of the power line to obtain information. A method for direct current power line communication in a photovoltaic system includes (a) transferring power between a photovoltaic device and a load using a power line, (b) changing operation of the power line, and (c) encoding operating state of the power line to represent information to be communicated.

Methods, apparatus and computer programs for transmitting and/or receiving information are described. Information encoded in a carrier signal comprising a modulation pattern superimposed on a grid frequency at which electricity flows in a synchronous area of an electric power grid, is decoded by measuring, at a receiving device, a characteristic relating to a frequency of electricity flowing in the electric power grid, accessing data indicative of one or more predetermined code patterns and performing a correlation process to determine a correlation between the modulation pattern and one of the one or more predetermined code patterns. The information is decoded on the basis of the determined correlation. This enables information to be easily transmitted within a synchronous area of the electric power grid.

A method for direct current power line communication in a photovoltaic system includes (a) transferring power between at least one photovoltaic device and a load using a power line, (b) maintaining a magnitude of a current flowing through the power line above a threshold value in a normal operating mode of the photovoltaic system, (c) detecting a change in operation of the power line in response to magnitude of a direct current component of the current flowing through the power line falling below the threshold value, and (d) in response to the detected change in operation of the power line, decoding operating state of the power line to obtain information.

A well tool for use in a wellbore can include a motor for performing a well operation. The well tool can include a switch that is couplable between the motor and a wireline. The switch can be toggleable between (i) a first operational state for providing the power to the motor by coupling the motor to an external power source and (ii) a second operational state for decoupling the motor from the external power source. The well tool can include a motor controller coupled to the switch for toggling the switch between the first operational state and the second operational state in an arrangement configured to impart, on the wireline, multiple current pulses including data encoded in the current pulses according to an encoding scheme.

A load control device may control power delivered from a power source, such as an alternating-current (AC) power source, to at least two electrical loads, such as a lighting load and a motor load. The load control device may include multiple load control circuit, such as a dimmer circuit and a motor drive circuit, for controlling the power delivered to the lighting load and the motor load, respectively. The load control device may adjust the rotational speed of the motor load in a manner so as to minimize acoustic noise generated by the load control device and reduce the amount of time required to adjust the rotational speed of the motor load. The load control device may remain powered when one of the electrical loads (e.g., the lighting load) has been removed (e.g., electrically disconnected or uninstalled) and/or has failed in an open state (has burnt out or blown out).

A load control device may control power delivered from a power source, such as an alternating-current (AC) power source, to at least two electrical loads, such as a lighting load and a motor load. The load control device may include multiple load control circuit, such as a dimmer circuit and a motor drive circuit, for controlling the power delivered to the lighting load and the motor load, respectively. The load control device may adjust the rotational speed of the motor load in a manner so as to minimize acoustic noise generated by the load control device and reduce the amount of time required to adjust the rotational speed of the motor load. The load control device may remain powered when one of the electrical loads (e.g., the lighting load) has been removed (e.g., electrically disconnected or uninstalled) and/or has failed in an open state (has burnt out or blown out).

A well tool for use in a wellbore can include a motor for performing a well operation. The well tool can include a switch that is couplable between the motor and a wireline. The switch can be toggleable between (i) a first operational state for providing the power to the motor by coupling the motor to an external power source and (ii) a second operational state for decoupling the motor from the external power source. The well tool can include a motor controller coupled to the switch for toggling the switch between the first operational state and the second operational state in an arrangement configured to impart, on the wireline, multiple current pulses including data encoded in the current pulses according to an encoding scheme.

The present application is concerned with a system for transmitting and/or receiving the control and sensing signals between the control units and the power electronic components. One system according to the present application comprises: a transceiver adapted to modulate the communication signal on a communication signal frequency band, and a coupler connected to the power conductor and adapted to couple the modulated communication signal to the power conductor. The present application also concerns a method for transmitting and receiving the control and sensing signals.