Abstract: A method for issuing an alert which includes the following steps:—carry out an R analysis on two or more physiological variable inputs;—carry out an N analysis on a primary physiological variable input;—issue an alert if the R analysis confirms a trend for each of the physiological variable inputs and the N analysis shows a statistically significant change in the primary physiological variable input; where the two or more physiological variable inputs include systolic or mean blood pressure and pulse volume, and the primary physiological variable input is systolic or mean blood pressure; such that the alert is a visual, audio, vibratory, tactile or a combination of two or more of these or an alert signal to an output unit configured to output the alert in one of those forms.

Abstract: A disturbance, for example, a frequency variation, is generated in at least a portion of the power distribution network. The disturbance may be generated, for example, by an uninterruptible power supply (UPS) or some other component of the power distribution network, such as a switch. At least one node of the network experiencing the disturbance is identified and a topology of the power distribution network is determined responsive to identifying the at least one node. The at least one node may be identified by detecting a voltage-related artifact corresponding to the disturbance. A phase-locked loop (PLL)—based circuit may be used for fast artifact detection. Groups of devices in the network may be identified from the artifacts, and combinatorial optimization techniques may be used to determine connectivity within such groups.

Abstract: A resonant converter including: a resonant tank, a switching circuit that connects the resonant tank to a power supply according to a first switching sequence, a synchronous rectifier circuit that supplies power to an output, wherein the rectifier circuit is switched according to a second switching sequence, and a phase delay module arranged to delay the second switching sequence with respect to the first switching sequence to achieve a desired power output, and a method of controlling the same.

Abstract: A three phase full resonant cyclo-converter suitable for converting a three phase AC supply to a DC output. In one embodiment the cyclo-converter consists of two half bridge cyclo-converters driving a resonant circuit. The main switching sequence of the cyclo-converter may consist of a switching sequence in which the phases of a three phase supply are switched in a repeating sequence from the largest to the smallest absolute voltage value of the supply phases.

Abstract: A three-phase resonant cyclo-converter, the cyclo-converter comprising a feed forward control module arranged to develop a feed forward signal for controlling a switching frequency of the cyclo-converter dependent on conditions of a power supply arranged to provide power to the cyclo-converter.

Abstract: A three-phase resonant cyclo-converter comprising a power control module, wherein the power control module is arranged to develop a plurality of repeating switching periods within a cycle, the power control module further arranged to: control the length of a first switching period in the cycle to adjust the power flow, and control the relative length of two or more further switching periods in the cycle to adjust the power factor, wherein the relative length is controlled based on a cross-product of voltage and current values associated with the further switching periods.

Abstract: A three-phase resonant cyclo-converter including a closed loop control module for controlling the switching frequency of the cyclo-converter, the closed loop control module including: a voltage signal development module arranged to develop a voltage signal representative of a voltage output waveform of the cyclo-converter, a storage module arranged to accumulate voltage signal values for phase portions of the voltage output waveform, where the voltage signal values are based on a voltage error signal and accumulated historical voltage signal values for the same corresponding phase portions, and a switching frequency control module arranged to develop a switching frequency control signal to control the switching frequency of the cyclo-converter based on the accumulated voltage signal values for corresponding phase portions of the voltage output waveform, and a proportional voltage signal based on a difference between the developed voltage signal and a reference voltage signal.

Abstract: A method for issuing an alert which includes the following steps:—carry out an R analysis on two or more physiological variable inputs;—carry out an N analysis on a primary physiological variable input;—issue an alert if the R analysis confirms a trend for each of the physiological variable inputs and the N analysis shows a statistically significant change in the primary physiological variable input; where the two or more physiological variable inputs include systolic or mean blood pressure and pulse volume, and the primary physiological variable input is systolic or mean blood pressure; such that the alert is a visual, audio, vibratory, tactile or a combination of two or more of these or an alert signal to an output unit configured to output the alert in one of those forms.

Abstract: A power converter providing required hold up for a primary converter, particularly a cycloconverter, without the required hold up capacity by an auxiliary converter including storage capacitors having the requisite capacity. The auxiliary converter may be isolated from the primary converter during normal operation and switched in during power supply discontinuities. The storage capacitors may be charged via a voltage step up circuit to achieve improved charge utilization. The storage capacitors may be charged via a charge path independent of the auxiliary converter output path so that the storage capacitor charging rate may be set independently.

Abstract: A power factor correction booster circuit for connection to an alternating current (AC) power source including a first circuit portion arranged to be active over a first AC half cycle of the power source, the first circuit portion including: a first AC input node in connection with a source node of a first power transistor, a first node of an inductive element in connection with a drain node of the first power transistor, a second node of the inductive element in connection with a drain node of a second power transistor, a second AC input node in connection with a source node of the second power transistor, an anode of a first semiconductor diode element in connection with the second node of the inductive element, a cathode of the first semiconductor diode element in connection with a first node of a first output capacitor element, and a second node of the first output capacitor element in connection with the second AC input node, wherein the first and second power transistors are controllable to switch the f

Abstract: A resonant converter including: a resonant tank, a switching circuit that connects the resonant tank to a power supply according to a first switching sequence, a synchronous rectifier circuit that supplies power to an output, wherein the rectifier circuit is switched according to a second switching sequence, and a phase delay module arranged to delay the second switching sequence with respect to the first switching sequence to achieve a desired power output, and a method of controlling the same.

Abstract: A three phase full resonant cyclo-converter suitable for converting a three phase AC supply to a DC output. In one embodiment the cycloconverter controls switching frequency to control converter output and adjusts phase on times for power factor correction. A switching sequence is employed which provides resonant switching to reduce losses and component ratings. The converter provides high conversion efficiency with a simple power component design.

Abstract: Apparatus for cancelling electromagnetic interference (EMI) during power conversion. In one embodiment, the apparatus comprises a power converter for converting a DC input to a DC output, wherein the power converter comprises a transformer having a primary winding and a secondary winding, the secondary winding coupled to a diode such that a plurality of secondary winding voltages cause a balanced current flow through a plurality of parasitic capacitances.

Abstract: A three-phase resonant cyclo-converter comprising a power control module, wherein the power control module is arranged to develop a plurality of repeating switching periods within a cycle, the power control module further arranged to: control the length of a first switching period in the cycle to adjust the power flow, and control the relative length of two or more further switching periods in the cycle to adjust the power factor, wherein the relative length is controlled based on a cross-product of voltage and current values associated with the further switching periods.

Abstract: A three-phase resonant cyclo-converter, the cyclo-converter comprising a feed forward control module arranged to develop a feed forward signal for controlling a switching frequency of the cyclo-converter dependent on conditions of a power supply arranged to provide power to the cyclo-converter.

Abstract: A three-phase resonant cyclo-converter including a closed loop control module for controlling the switching frequency of the cyclo-converter, the closed loop control module including: a voltage signal development module arranged to develop a voltage signal representative of a voltage output waveform of the cyclo-converter, a storage module arranged to accumulate voltage signal values for phase portions of the voltage output waveform, where the voltage signal values are based on a voltage error signal and accumulated historical voltage signal values for the same corresponding phase portions, and a switching frequency control module arranged to develop a switching frequency control signal to control the switching frequency of the cyclo-converter based on the accumulated voltage signal values for corresponding phase portions of the voltage output waveform, and a proportional voltage signal based on a difference between the developed voltage signal and a reference voltage signal.

Abstract: A disturbance, for example, a frequency variation, is generated in at least a portion of the power distribution network. The disturbance may be generated, for example, by an uninterruptible power supply (UPS) or some other component of the power distribution network, such as a switch. At least one node of the network experiencing the disturbance is identified and a topology of the power distribution network is determined responsive to identifying the at least one node. The at least one node may be identified by detecting a voltage-related artifact corresponding to the disturbance. A phase-locked loop (PLL)—based circuit may be used for fast artifact detection. Groups of devices in the network may be identified from the artifacts, and combinatorial optimization techniques may be used to determine connectivity within such groups.

Abstract: A switched mode power supply allowing a half bridge converter to be use alone or in combination with another converter to form a full bridge converter. A common controller may be used for either half bridge or full bridge configurations. The modular approach simplifies design for a range of power supplies and reduces costs.

Abstract: A three phase full resonant cyclo-converter suitable for converting a three phase AC supply to a DC output. In one embodiment the cyclo-converter consists of two half bridge cyclo-converters driving a resonant circuit. The main switching sequence of the cyclo-converter may consist of a switching sequence in which the phases of a three phase supply are switched in a repeating sequence from the largest to the smallest absolute voltage value of the supply phases.

Abstract: A power converter providing required hold up for a primary converter, particularly a cycloconverter, without the required hold up capacity by an auxiliary converter including storage capacitors having the requisite capacity. The auxiliary converter may be isolated from the primary converter during normal operation and switched in during power supply discontinuities. The storage capacitors may be charged via a voltage step up circuit to achieve improved charge utilization. The storage capacitors may be charged via a charge path independent of the auxiliary converter output path so that the storage capacitor charging rate may be set independently.