Abstract: To solve problems arising when a power conditioner equivalent to that connected to a solar panel is connected to a power storage device. Direct-current power generated by the solar panel 9 is supplied to a DC-DC converter 51 and output as a predetermined direct-current voltage. The output voltage of the converter 51 is supplied to a DC-AC inverter 52. Direct-current power generated by the power storage device 11 is supplied to a DC-DC converter 55. Predetermined direct-current power from the converter 55 is supplied to a DC-AC inverter 56. Alternating-current power output by the inverter 56 is supplied to an alternating-current power system at home. The converter 55 is configured to have two output voltages. The first output voltage is a standby voltage. The second voltage is a voltage at which the inverter 56 starts power supply to outside.

Abstract: Used electric energy is collected while maintaining accuracy. Information to be displayed on a display 14 is generated in such a way that a gateway 4 processes a measured value (with a time stamp) transmitted from a power meter 2, an appliance monitor 5, a solar module 10, and a battery center 13 through a wireless LAN. In the gateway 4, the used electric energy is synchronized with each other by the time stamp. Further, an integrated value of the used electric energy in the time direction is calculated. The information can be secured by obtaining the integrated value of data even if breakdown of devices and the like due to power failure occurs.

Abstract: An inductive power transfer system comprises a primary unit operable to generate an electromagnetic field and at least one secondary device, separable from the primary unit, and adapted to couple with the field when the secondary device is in proximity to the primary unit so that power can be received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween. The system detects if there is a substantial difference between, on the one hand, a power drawn from the primary unit, and on the other hand, a power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices. Following such detection, the system restricts or stops the inductive power supply from the primary unit. Such a system can detect the presence of unwanted parasitic loads in the vicinity of the primary unit reliably.

Abstract: A grid tied inverter connectable to an electricity grid, the grid tied inverter comprising a DC to DC current fed push-pull converter operable to generate a current waveform from a DC voltage source, the current waveform being substantially synchronised to the electricity grid, the push-pull converter comprising a transformer having a first side connectable to a battery and a second side connectable to the grid, wherein each of the two primary sides is connected to ground via a switching transistor; and respective voltage clamps are connected between the respective primary side of the transformer and the respective switching transistor, the voltage clamp commutating the current from the respective primary side of the transformer when the switching transistor is turned off.

Abstract: A grid tied inverter connectable to an electricity grid, the grid tied inverter comprising a DC to DC current fed push-pull converter operable to generate a current waveform from a DC voltage source, the current waveform being substantially synchronised to the electricity grid, and a transformer having a first side connected to the DC to DC current fed converter and a second side having an output line connectable to the grid.

Abstract: A grid tied inverter comprising an unfolding circuit connectable to an electricity grid; and a DC to DC current fed converter operable to generate a current waveform from a battery, the current waveform being substantially synchronised to the electricity grid, wherein the unfolding circuit is operable, in a first mode, to convert the current into a sinusoidal waveform have an instantaneous voltage suitable for injection onto the grid.

Abstract: An inductive power transfer system comprises a primary unit operable to generate an electromagnetic field and at least one secondary device, separable from the primary unit, and adapted to couple with the field when the secondary device is in proximity to the primary unit so that power can be received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween. The system detects if there is a substantial difference between, on the one hand, a power drawn from the primary unit, and on the other hand, a power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices. Following such detection, the system restricts or stops the inductive power supply from the primary unit. Such a system can detect the presence of unwanted parasitic loads in the vicinity of the primary unit reliably.

Abstract: An inductive power transfer system comprises a primary unit, having a primary coil and an electrical drive unit which applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device, separable from the primary unit and having a secondary coil which couples with the field when the secondary device is in proximity to the primary unit. A control unit causes a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unit takes one or more measures of such energy decay during the measurement period.

Abstract: An inductive power transfer system (1) comprises a primary unit (10) operable to generate an electromagnetic field and at least one secondary device (30), separable from the primary unit, and adapted to couple with the field when the secondary device is in proximity to the primary unit so that power can be received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween. The system detects if there is a substantial difference between, on the one hand, a power drawn from the primary unit and, on the other hand, a power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices. Following such detection, the system restricts or stops the inductive power supply from the primary unit. Such a system can detect the presence of unwanted parasitic loads in the vicinity of the primary unit reliably.

Abstract: An inductive power transfer system comprises a primary unit, having a primary coil and an electrical drive unit which applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device, separable from the primary unit and having a secondary coil which couples with the field when the secondary device is in proximity to the primary unit. A control unit causes a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unit takes one or more measures of such energy decay during the measurement period.

Abstract: An inductive power transfer system comprises a primary unit 10, having a primary coil 12 and an electrical drive unit 14 which applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device 30, separable from the primary unit and having a secondary coil 32 which couples with the field when the secondary device is in proximity to the primary unit. A control unit 16 causes a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unit 18 takes one or more measures of such energy decay during the measurement period.

Abstract: An inductive power transfer system comprises a primary unit 10, having a primary coil 12 and an electrical drive unit 14 which applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device 30, separable from the primary unit and having a secondary coil 32 which couples with the field when the secondary device is in proximity to the primary unit. A control unit 16 causes a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unit 18 takes one or more measures of such energy decay during the measurement period.

Abstract: An inductive power transfer system (1) comprises a primary unit (10) operable to generate an electromagnetic field and at least one secondary device (30), separable from the primary unit, and adapted to couple with the field when the secondary device is in proximity to the primary unit so that power can be received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween. The system detects if there is a substantial difference between, on the one hand, a power drawn from the primary unit and, on the other hand, a power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices. Following such detection, the system restricts or stops the inductive power supply from the primary unit. Such a system can detect the presence of unwanted parasitic loads in the vicinity of the primary unit reliably.

Abstract: An inductive power transfer system (1) comprises a primary unit (10) operable to generate an electromagnetic field and at least one secondary device (30), separable from the primary unit, and adapted to couple with the field when the secondary device is in proximity to the primary unit so that power can be received inductively by the secondary device from the primary unit without direct electrical conductive contacts therebetween. The system detects if there is a substantial difference between, on the one hand, a power drawn from the primary unit and, on the other hand, a power required by the secondary device or, if there is more than one secondary device, a combined power required by the secondary devices. Following such detection, the system restricts or stops the inductive power supply from the primary unit. Such a system can detect the presence of unwanted parasitic loads in the vicinity of the primary unit reliably.

Abstract: An inductive power transfer system comprises a primary unit (10), having a primary coil (12) and an electrical drive unit (14) which applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device (30), separable from the primary unit and having a secondary coil (32) which couples with the field when the secondary device is in proximity to the primary unit. A control unit (16) causes a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unit (18) takes one or more measures of such energy decay during the measurement period.

Abstract: An inductive power transfer system comprises a primary unit 10, having a primary coil 12 and an electrical drive unit 14 which applies electrical drive signals to the primary coil so as to generate an electromagnetic field. The system also comprises at least one secondary device 30, separable from the primary unit and having a secondary coil 32 which couples with the field when the secondary device is in proximity to the primary unit. A control unit 16 causes a circuit including said primary coil to operate, during a measurement period, in an undriven resonating condition. In this condition the application of the drive signals to the primary coil by the electrical drive unit is suspended so that energy stored in the circuit decays over the course of the period. A decay measurement unit 18 takes one or more measures of such energy decay during the measurement period.

Abstract: A magnetic transducer (109) for measuring the flow of a fluid (108) has electrodes (102) and an alternating magnetic field (107), an electrode (102) having lower noise energy at frequencies below 5 Hz than an electrode comprising carbon or corrosion-resistant metal alloy. The noise characteristic of the electrode (102) at magnetic field frequencies around 1 Hz is lower than that of an electrode comprising carbon or corrosion-resistant metal alloy.