4441results about "Conversion with intermediate conversion to dc" patented technology

The present invention focuses on the development of a high-performance solar photovoltaic (PV) energy conversion system. The power circuit of the invention is made of a two-stage circuit, connecting a step-up DC-DC converter and a full-bridge inverter in serial. The present invention uses an adaptive perturbation and observation method to increase tracking speed of maximum power position and at the same time reduces energy loss. In addition, the full-bridge inverter's output has to have the same phase with the utility power in order to achieve unit power factor and increase the system efficiency. The present invention uses voltage type current control full-bridge inverter to achieve the goal of merging into utility grid. The present invention provides an active Sun tracking system, by utilizing the character of changing in open circuit output voltage with Sun radiation strength to follow the Sun, and decreases the system cost and increases system effectiveness.

This invention improves the performance and lowers the cost of DC to AC inverters and the systems where these inverters are used. The performance enhancements are most valuable in renewable and distributed energy applications where high power conversion efficiencies are critical. The invention allows a variety of DC sources to provide power thru the inverter to the utility grid or directly to loads without a transformer and at very high power conversion efficiencies. The enabling technology is a novel boost converter stage that regulates the voltage for a following DC to AC converter stage and uses a single semiconductor switching device. The AC inverter output configuration is either single-phase or three-phase.

A method to convert direct current (DC) power generated by a photovoltaic (PV) arrays to alternating current (AC) power using a PV inverter, the method includes: applying the DC power generated the PV array to the PV inverter; boosting the DC power from the PV array from a predetermined voltage level to a predetermine DC link voltage, wherein the PV array is regulated by the boosting to output a voltage at the predetermined voltage level; converting the boosted DC power to AC power, and disabling the boost of the power generated by the PV array after the array has a predetermined voltage level at least as great as the DC link voltage.

A power converter includes a DC to AC inverter that is connected to a neutral node formed between first and second capacitors connected across two DC supply lines. The inverter is operated to selectively couple the DC supply lines and the neutral node to an output terminal thereby producing an alternating voltage waveform formed by a sequence of output pulses having positive, zero and negative voltage levels. To compensate for a voltage imbalance across the capacitors, an imbalance compensation coefficient is derived from the difference in voltages across the first and second capacitors and from the direction of current between the neutral node and the inverter. The imbalance compensation coefficient is employed to adjust the width of the output pulses so as to charge and discharge the capacitors to correct the imbalance.

A contactless electrical energy transmission system includes a transformer having a primary winding that is coupled to a power source through a primary resonant circuit and a secondary winding that is coupled to a load through a secondary resonant circuit. The primary and secondary resonant circuits are inductively coupled to each other. A primary control circuit detects current changes through the primary resonant circuit to control the switching frequency of a controllable switching device for maintaining a substantially constant energy transfer between the primary winding and secondary winding in response to at least one of a power source voltage change and a load change. As a result, excessive circulating energy of the CEET system is minimized providing a tight regulation of the output voltage over the entire load and input voltage ranges without any feedback connection between the primary side and the secondary side.

The invention relates to a conditioning circuit that measures operating points of a power supply to deduce therefrom the current-voltage characteristic thereof and to determine directly the voltage corresponding to its maximum power point, without using any kind of tracking algorithm that causes the operating point of the power unit to oscillate about the maximum power point. The maximum power point voltage VMPP is supplied to a controller which regulates a power cell by slaving it to the input voltage until the output voltage of the supply is equal to the maximum power point voltage V_MPP. The invention also relates to a solar generator and an associated conditioning method. One particular application is to high-power satellites.

An object of the present invention is to provide a photovoltaic power generation system which is capable of achieving system linkage of a plurality of solar cell strings having different output voltages to a commercial electric power system with ease, and which enables efficient use of the maximum output electric power. It is a photovoltaic power generation system characterized by disposing voltage regulating means that regulates a DC voltage outputted from non-standard solar cell string between a standard solar cell string and electric power converting means, and regulating an output voltage of the non-standard solar cell string to the side of an output voltage of the standard solar cell string by the use of the voltage regulating means.

A power converter system advantageously employs a modular, bi-directionally symmetrical power converter assembly in a readily customizable configuration to interconnect a direct current power source to a three-phase alternating power grid. Connections external to the power converter assembly are selected to optimize the power converter system for a specific application, such as interconnecting a photovoltaic array to the three-phase electrical power grid. The electrical interconnections of various elements including isolation transformers, voltage sensors, and control switches are optimized to improve efficiency and reliability.

A method and apparatus for converting Direct Current (DC) to Alternating Current (AC). The method comprises performing system analysis on at least one of a DC current, DC voltage, or an AC voltage; utilizing the system analysis for selecting at least one conversion parameter; and converting DC to AC utilizing the at least one conversion parameter.