6487 results about "Power factor" 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.

A synchronous full bridge rectifier is controlled to provide a power factor near unity. The full bridge rectifiers are transistors each with a controlling input. The AC input signal and currents within the circuit are sensed and sent to a controller. In response, the controller output control signals to turn on / off the rectifying MOSFETS on a timely basis to form a power factor of near one with respect to the AC input signal. The full wave rectifier is made of N-channel MOSFET's, some with fast body diodes. The MOSFET's are rectifiers and PFC control elements. The result is a one stage synchronous rectifier with PFC. A solid state precision analog differential amplifier senses the AC line waveform and high frequency current transformers sense the currents. The controller accepts the inputs of the amplifier and the sensed currents and outputs control signals that turn on and off the four MOSFET's. The timing of turning on / off is arranged so that the current drawn from the AC source is sinusoidal and matches the phase of the sinusoidal AC source.

A new fluorescent lamp comprises a lamp tube and an electronic ballast, it is characterized in that it is provided with an outer tube, there are respectively an outer plug at both ends of the outer tube, in which inserts a socket for the lamp tube. The electronic ballast is between the outer plug and the socket for the lamp tube at one end, said lamp tube is disposed between two sockets for the lamp tube. There are advantages as follows: an urgent lighting, the electronic ballast and the compact lamp tube are integrated as one whole; it is convenient for mounting and exchanging, a cost for mounting is greatly reduced; it is possible for repacking to maintain an original means, to reduce a contamination of waste; its weight is light; its power factor is high, more than 95%, it is economical in power, a cost for transporting is low; the color rendering index (CRI) is more than 80%; it is ignited immediately after it is turned on, it does not flash; it is applied to lamps having deferent power; the life of the lamp tube is prolonged by 50%; its output brightness is higher than existing lamps by twice or more; the lamp tube still steadily operates when a power supply is unexpected to be shut off, which reduces accident cases; the whole distortion of a resonant wave becomes smaller than 30%.

The switching rectifier and switching inverter on a motor drive unit are modulated to indirectly change the magnitude of current and voltage stored in DC link by controlling the magnetic field of the motor to correct for both power factor lead and power factor lag over a wide range of motor speeds and conditions while maintaining a predetermined motor operating point.

An induction motor drive system and method estimates a motor power factor based on the AC power output to the motor phase windings and estimates the rotor speed based on the estimated power factor. The estimated rotor speed is compared to a rotor speed command signal to generate a speed error, and the voltage and frequency input to the motor are adjusted in response to the speed error. Rotor speed is estimated based on estimated rotor slip, which is estimated based on the applied voltage, frequency, estimated power factor and estimated motor power.