When a pulsed waveform is used to transmit power-supply power in a form of a power packet etc., a filter for reducing harmonic components is disposed on a power transmission side. A switch and a control portion for controlling ON/OFF of a function of the filter are provided to turn ON the function of the filter limitedly at each of timings t1 to t2 and t3 to t4 at which the power is transmitted. The harmonic components are reduced from the waveform of the transmission power by the function of the filter. Radiation noise generated by the wire harness is reduced in a high frequency region. The function of the filter is turned OFF at a timing at which digital information is transmitted so that a waveform of the digital information can be prevented from being deformed.

The presence of injected DC has harmful consequences for a power grid system. A piecewise sinusoidal ripple voltage wave at the line-frequency that rides on the main capacitor bank of the power converter is observed. This observation leads to a new DC detection elimination method. Three DC elimination methods for this ripple component are disclosed to allow dissipation of DC energy through heat and/or electromagnetic wave, or to allow transformation of this energy into usable power that is fed back into the power grid.

The presence of injected DC has harmful consequences for a power grid system. A piecewise sinusoidal ripple voltage wave at the line-frequency that rides on the main capacitor bank of the power converter is observed. This observation leads to a new detection method and mitigation method. A two-stage control circuit is added to the operation of a power converter that controls power line impedance in order to mitigate the injected DC and to block DC circulation. This control computes a correction angle to adjust the timing of generated pulsed square waves to counter-balance the ripple. A functional solution and the results of experiments are presented. Furthermore, an extraction method and three elimination methods for this ripple component are presented to allow dissipation of DC energy through heat and/or electronic magnetic wave, or to allow transformation of this energy into usable power that is fed back into the power grid.

Aspects of the subject disclosure may include, for example, a coupling device includes a circuit that receives a signal. At least one passive electrical circuit element generates an electromagnetic field in response to the signal. A portion of the electromagnetic field is guided by a surface of a transmission medium to propagate as a guided electromagnetic wave longitudinally along the transmission medium. Other embodiments are disclosed.

An electrical device with a power switch has at least two different electrical operational states and a circuit which detects a sequence of momentary fluctuations of power defining a First user message, corresponding to a change in state. The circuit implements that change in state in response to detection of the First message. Another circuit detects a sequence of momentary fluctuations of power, different from the sequence of the First user message, defining a Second user message and defining a fixed Reset electrical operational state. The device also implements a change from the current electrical operational state, to the fixed Reset electrical operational state. A memory circuit stores the current electrical operational state, a number corresponding to one of the countable numbers of electrical operational state, and provides retentions of its memory, including the stored current electrical operational state, during periods of power off.

A control circuit of a code modulator sets first to third states to a code modulation circuit. In first state, first and fourth switch circuits are on, and second and third switch circuits are off. In second state, first and fourth switch circuits are off, and second and third switch circuits are on. In third state, all first to fourth switch circuits are on during transition from the first to second state, and vice versa. A control circuit of a code demodulator sets fourth to sixth states to a code demodulation circuit. In fourth state, fifth and eighth switch circuits are off, and sixth and seventh switch circuits are on. In fifth state, fifth and eighth switch circuits are on, and sixth and seventh switch circuits are off. In sixth state, all fifth to eighth switch circuits are on during transition from fourth to fifth state, and vice versa.

Systems and method for synchronizing power generators with a power grid are provided. One system among various implementations includes a plurality of synchronization modules, wherein each synchronization module corresponds to one power generator. The synchronization modules are configured to output a control signal to adjust a frequency of the respective power generator to correspond with the frequency of the existing power grid. The system also includes a central controller in communication with the plurality of synchronization modules. The central controller is configured to determine a propagation delay with respect to each synchronization module. The propagation delay is a measure of time for a signal to propagate from the respective synchronization module to the central controller. The central controller is further configured to send a control signal to each synchronization module to control when each synchronization module connects the respective power generator to the existing power grid.

Each one of code modulators modulates first power to generate a code-modulated wave using a modulation code based on a code sequence, and transmits the code-modulated wave to one of code demodulators. Each one of code demodulator receives the code-modulated wave from one of the code modulators, and demodulates the received code-modulated wave to generate second power using a demodulation code based on a code sequence identical to the code sequence of the modulation code used. When power is transmitted between each one of transmitter and receiver pairs, a controller selects and assigns code sequences to the transmitter and receiver pairs, so as to reduce an average of an absolute value of a total current of the code-modulated waves of the transmitter and receiver pairs in a transmission path, as compared to a reference value, the average being averaged over a predetermined time.

A pressure sewer control system includes a server in communication with one or more pressure sewer installations across a communications network, each of the one or more pressure sewer installations including a controller and one or more sewerage tanks. The server is configured to: determine weather data for a region associated with the pressure sewer installation; estimate power generating capability of a weather-dependent power generator based on the weather data; receive fluid level data indicative of a fluid level in the one or more sewerage tanks from the controller; determine whether a pump action should be instigated by the controller to pump fluid from the sewage tank based on the estimated power generating capability of the weather-dependent power generator and the fluid level data; and transmit a pump control instruction to the controller.

A method of preventing disjunctions in a power distribution unit having a plurality of output connectors is disclosed. A power level of each of the output connectors is sensed. It is detected that the power level of a given output connector exceeds a fixed power limit. In response to the detection, a delivery of power by the given output connector is stopped while maintaining a delivery of power by a remainder of the output connectors. Power delivery may be resumed in response to receiving a user command to rearm the given output connector. A power distribution unit adapted to prevent disjunctions is also disclosed.