25365results about "Ac-dc conversion" patented technology

A power subsystem is actively optimized to improve total subsystem efficiency in a way that is responsive to changes in load requirements, power supply variations, and subsystem temperature variations. Detailed, multidimensional power loss models are developed for constituent devices which are then combined into a power subsystem containing a controller and circuity for measuring device operating parameters such as input and output voltage, output current, and temperature. Operating parameters are continually monitored, and set points are correspondingly changed based on the detailed power loss models to achieve maximum overall efficiency for the instantaneous operating state of the system.

A modular apparatus for and method of alternating current photovoltaic power generation comprising via a photovoltaic module, generating power in the form of direct current; and converting direct current to alternating current and exporting power via one or more power conversion and transfer units attached to the module, each unit comprising a unitary housing extending a length or width of the module, which housing comprises: contact means for receiving direct current from the module; one or more direct current-to-alternating current inverters; an alternating current bus; and contact means for receiving alternating current from the one or more inverters.

A controller for a power converter and method of operating the same employable with a bridge rectifier having first and second synchronous rectifier switches. In one embodiment, the controller includes an amplifier configured to enable a turn-on delay for the first synchronous rectifier switch. The controller also includes a discharge switch having first and second switched terminals coupled to gate and source terminals, respectively, of the first synchronous rectifier switch and configured to discharge a gate-to-source capacitance of the first synchronous rectifier switch to enable a turn off thereof.

The present invention provides a primary-side flyback power converter that supplies a constant voltage output and a constant current output. To generate a well-regulated output voltage under varying load conditions, a PWM controller is included in the power converter in order to generate a PWM signal controlling a switching transistor in response to a flyback voltage sampled from a first primary winding of the power supply transformer. Several improvements are included in this present invention to overcome the disadvantages of prior-art flyback power converters. Firstly, the flyback energy of the first primary winding is used as a DC power source for the PWM controller in order to reduce power consumption. A double sample amplifier samples the flyback voltage just before the transformer current drops to zero. Moreover, an offset current is pulled from a detection input of the double sample amplifier in order to generate a more accurate DC output voltage. The offset current is generated in response to the temperature in order to compensate for temperature-induced voltage fluctuations across the output rectifier. Ultimately, in order to maintain a constant output current, the PWM controller modulates the switching frequency in response to the output voltage.

An apparatus and method of control for converting DC (direct current) power from a solar photovoltaic source to AC (alternating current) power. A novel DC-to-AC power converter topology and a novel control method are disclosed. This combination of topology and control are very well suited for photovoltaic microinverter applications. Also, a novel variant of this control method is illustrated with a number of known photovoltaic DC-to-AC power converter topologies. The primary function of both control methods is to seek the maximum power point (MPP) of the photovoltaic source with novel, iterative, perturb and observe control algorithms. The control portion of this invention discloses two related control methods, both an improvement over prior art by having greatly improved stability, dynamic response and accuracy.

A maximum power point tracking method, applied to a tracking device, employs a DC / DC converter connecting with a solar cell array, and including a controller actuating the DC / DC converter to perform an active resistance characteristic; a maximum power point tracking circuit adjusting the active resistance of the DC / DC converter; monitoring a change of an output power of the solar cell array in determining a direction for adjusting the active resistance of the DC / DC converter; and the maximum power point tracking circuit repeatedly adjusting the active resistance of the DC / DC converter. If the change of the output power of the solar cell array is positive, the active resistance of the DC / DC converter is adjusted in the same direction; but, conversely, if the change of the output power of the solar cell array is negative, the active resistance of the DC / DC converter is adjusted in an opposite direction.

In a power generation system which includes a plurality of sets of direct current power sources and power converters which are connected to the direct current power sources to convert a direct current power into an alternating current power, the power converters being connected in parallel to supply the alternating current power to a system power supply, from the plurality of power converters in the system, one power converter is set as a master machine which detects an islanding operation state in which power supply from the system power supply is stopped, and setting is executed so as to cause the remaining power converters not to detect the islanding operation state. When the master machine is not present among the power converters in operation, the master machine is selected from the power converters in operation in accordance with a predetermined condition.

A system for minimizing neuromuscular stimulation includes a converter, an inverter, and a controller. The converter is configured to output a dc waveform and includes at least one first switching element operated at a first duty cycle. The inverter is coupled to the converter and includes at least one second switching element operated at a second duty cycle. The inverter is configured to invert the DC waveform to generate an electrosurgical pulse waveform. The controller is coupled to the converter and the inverter, and is configured to control the first duty cycle to adjust a magnitude of the electrosurgical pulse waveform and the second duty cycle to adjust at least one property of the electrosurgical pulse waveform to minimize neuromuscular stimulation.

A power control circuit is provided containing a switch array, which includes segmented switches, a flying capacitor, an output voltage terminal, a feedback loop, and a digital voltage regulator block. The digital voltage regulator block includes an A / D converter, an encoder, an add-subtractor, and a gate logic. These power control circuits do not include pass transistors. A method is also provided, where the charge pumps of the power control circuit are operated in two-phase cycles including a charging phase and a pumping phase. The power control circuit is controlled in both of these phases, thereby reducing the ripple of the output voltage.