A PoDL system includes a PSE connected via a wire pair to a PD, where differential data and DC power are transmitted over the same wire pair. Typically, low voltage/current detection and classification routines are required upon every powering up of the system to allow the PD to convey its PoDL requirements to the PSE. Various techniques are described that simplify or obviate such start-up routines or enable increased flexibility for the PoDL system. Such techniques include: ways to specify a particular PD operating voltage; ways to disable the PD's UVLO circuit during such routines; using opposite polarity voltages for the two routines; using voltage limiters or surge protectors to convey the PoDL information; detecting loop resistance; using a PSE memory to store previous results of the routines; and powering the PD communication circuit using the wire pair while the PD load is powered by an alternate power source.

A power management system comprises a plurality of HEMSs 10 and a CEMS 40. The CEMS 40 transmits, to each HEMS 10, a notification request for requesting a notification of an amount of power that can be reduced from power currently consumed by a load connected to each HEMS 10, in response to a power curtailment signal. Each HEMS 10 transmits, to the CEMS 40, reducible power information including the amount of power that can be reduced from the power currently consumed, in response to the notification request. The CEMS 40 transmits, to each HEMS 10, power reduction information including an amount of power that should be reduced in each consumer 70, in response to the power curtailment signal and the reducible power information.

A power management system comprises a plurality of HEMSs 10 and a CEMS 40. The CEMS 40 transmits, to each HEMS 10, a notification request for requesting a notification of an amount of power that can be reduced from power currently consumed by a load connected to each HEMS 10, in response to a power curtailment signal. Each HEMS 10 transmits, to the CEMS 40, reducible power information including the amount of power that can be reduced from the power currently consumed, in response to the notification request. The CEMS 40 transmits, to each HEMS 10, power reduction information including an amount of power that should be reduced in each consumer 70, in response to the power curtailment signal and the reducible power information.

A centralized voltage control device connected, via a communication network, to local voltage control devices connected to voltage control apparatuses, including: a transmission and reception unit receiving the number of times a tap position is changed per fixed time of the voltage control apparatus from the local voltage control device; a dead-zone-width updating unit increasing a dead zone width when the number of times a tap position is changed in a voltage control apparatus of a transformer type is a threshold or larger; and a voltage-upper-and-lower-limit-value determining unit determining the voltage upper limit value and the voltage lower limit value for each local voltage control device and issuing a command regarding these values to each local voltage control device, and determining the voltage upper limit value and the voltage lower limit value of the voltage control apparatus of a transformer type on the basis of the dead zone width.

A power source apparatus that combines power generated by a photovoltaic system and power generated from another power source by using a power combiner and transmits the combined power to a load side, wherein an output voltage of the photovoltaic system can be changed by changing a cell connection state of a plurality of solar cells of the photovoltaic system, and the highest efficiency of the photovoltaic system can be obtained by adding the output voltage of the photovoltaic system to an output voltage of the another power source.

A power source apparatus that combines power generated by a photovoltaic system and power generated from another power source by using a power combiner and transmits the combined power to a load side, wherein an output voltage of the photovoltaic system can be changed by changing a cell connection state of a plurality of solar cells of the photovoltaic system, and the highest efficiency of the photovoltaic system can be obtained by adding the output voltage of the photovoltaic system to an output voltage of the another power source.

Disclosed is a method of and control system for operating a circuit arrangement, in particular a circuit arrangement of an electric vehicle for inductive power transfer to the vehicle. The circuit arrangement includes at least one phase line with at least one field receiving arrangement and at least one compensating arrangement with a variable reactance, wherein at least one current-dependent cost function is evaluated, wherein the reactance is varied such that the cost function is optimized.

A centralized voltage controller connected, via a communication network, to local voltage control units controlling voltage controllers, which are connected to a distribution line of a distribution system and control voltage of the distribution line, has: a voltage distribution determination unit calculating a controlled amount for each first voltage controller to be controlled among the plurality of voltage controllers, based on a measured value of voltage at each point of the distribution line; a tap position determination unit generating a command value to be given to each local voltage control unit based on the controlled amount; and a control state determination unit determining whether each voltage controller is a second voltage controller that fails to perform control according to the command value, and setting the voltage controllers except the second voltage controller to be the first voltage controller.

A centralized voltage controller connected, via a communication network, to local voltage control units controlling voltage controllers, which are connected to a distribution line of a distribution system and control voltage of the distribution line, has: a voltage distribution determination unit calculating a controlled amount for each first voltage controller to be controlled among the plurality of voltage controllers, based on a measured value of voltage at each point of the distribution line; a tap position determination unit generating a command value to be given to each local voltage control unit based on the controlled amount; and a control state determination unit determining whether each voltage controller is a second voltage controller that fails to perform control according to the command value, and setting the voltage controllers except the second voltage controller to be the first voltage controller.

A doorbell system and a doorbell control device are provided. The doorbell system includes a doorbell control device, a transformer, and a doorbell interface device. The doorbell control device has a first pin, a second pin, and a third pin. The doorbell control device includes a speaker unit and a control unit. The control unit is configured to control whether or not the speaker unit produces sound according to a current or a voltage of the second pin. The first pin is coupled to the second pin. The transformer outputs an AC voltage to the first pin and the third pin of the doorbell control device. The doorbell interface device is coupled to the second pin and the third pin of the doorbell control device.