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2739results about How to "Reduce electromagnetic interference" patented technology

Topology and control method for power factor correction

In a power factor corrected AC-to-DC power supply system, a DC-to-DC power converter is coupled to the output of an AC-to-DC power converter in order to produce a regulated DC output signal from a rectified AC input signal. The AC-to-DC power converter and the DC-to-DC power converter each includes a switch for controlling the operation of their respective power converter. The AC-to-DC converter includes an inductor. The system provides power factor correction for minimizing harmonic distortion by including a controller that receives the regulated DC output voltage as a feedback signal, and in response, produces a series of drive pulses having predetermined constant duty cycle. These pulses are simultaneously fed to each switch, to operate the respective converters alternately between ON and OFF states. When the AC-to-DC converter is driven by a fixed duty cycle of the series of pulses, power factor correction is improved since the current flowing through the inductor is substantially proportional to the waveform of the rectified AC input signal. By preselecting the value of the inductor, the AC-to-DC converter is operable in a discontinuous mode when the instantaneous rectified AC input signal is low and in a continuous mode when the instantaneous rectified AC input signal is high.
Owner:ASTEC INT LTD

High efficiency incandescent bulb replacement lamp

The invention discloses a high efficiency incandescent and Compact Fluorescent (CFL) bulb replacement LED lamp having a good color reproduction. The LED light bulb includes two groups of semiconductor light emitters and a luminescent material to emit four different spectrums of light. The two groups of semiconductor light emitters are enclosed around an interior wall of the light bulb housing, which has a plurality of fins at an exterior surface for effective heat dissipation. A high reflective member having a dome shape in the center is disposed under the two groups of semiconductor light emitters to redirect the emission and excitation lights from the two groups of semiconductor light emitters and recycle the backscattered light for multi-spectrum light mixing. The LED-light bulb further includes a single power line connecting to the two groups of semiconductor light emitters and a high efficiency electrical AC/DC conversion and control device. The light bulb has a diffuser dome for an output window and a conventional Edison-mount screw-type light bulb socket, a conventional fluorescent tube coupler arrangement or a conventional halogen MR-16 socket arrangement connecting to an AC power base. If a voltage is supplied to the AC/DC conversion and control device, a mixture light from the diffuser dome produces a warm white light with a color rendering index of at least 85 and a luminous efficacy of at least 80 lumens per watt.
Owner:LEDNOVATION

Multiphase soft switched DC/DC converter and active control technique for fuel cell ripple current elimination

ActiveUS7518886B1Cost size reductionElimination of voltage clampingDc-dc conversionDynamo-electric converter controlInner loopVoltage reference
DC / DC converter has a transformer having primary coils connected to an input side and secondary coils connected to an output side. Each primary coil connects a full-bridge circuit comprising two switches on two legs, the primary coil being connected between the switches on each leg, each full-bridge circuit being connected in parallel wherein each leg is disposed parallel to one another, and the secondary coils connected to a rectifying circuit. An outer loop control circuit that reduces ripple in a voltage reference has a first resistor connected in series with a second resistor connected in series with a first capacitor which are connected in parallel with a second capacitor. An inner loop control circuit that reduces ripple in a current reference has a third resistor connected in series with a fourth resistor connected in series with a third capacitor which are connected in parallel with a fourth capacitor.
Owner:VIRGINIA TECH INTPROP INC

Scalable high-swing transmitter with rise and/or fall time mismatch compensation

Disclosed is a high-swing voltage-mode transmitter or line driver. The transmitter can operate over a wide range of supply voltages. Increasing the available output swing merely involves increasing the supply voltage; the circuit adapts to maintain the desired output impedance. This allows for a tradeoff between output amplitude and power consumption. Another advantage of the proposed architecture is that it compensates for process, voltage, and temperature (PVT) and mismatch variations so as to keep rise and fall times matched. This feature reduces common-mode noise and hence EMI in systems in which the transmitter is used.
Owner:MICROSEMI STORAGE SOLUTIONS

Microminiature personal combined navigation system as well as navigating and positioning method thereof

InactiveCN102445200AReduce electromagnetic interferenceSuitable for personal portabilityNavigation instrumentsAccelerometerGyroscope
The invention discloses a microminiature personal combined navigation system as well as a navigating and positioning method thereof. The system is composed of a subsystem installed on the foot part of a human body and a subsystem installed on the trunk position, wherein the subsystem installed on the foot part comprises an MEMS IMU (Micro-electromechanical Systems Inertial Measurement Unit), a magnetometer and a communication module; and the subsystem installed on the trunk position comprises a satellite navigation receiver, a Doppler velometer, an atmospheric pressure altimeter, a communication module and a microminiature navigation computer. The positioning method comprises the following steps of: collecting the MEMS IMU signal; modeling and correcting the random error of a gyroscope and an accelerometer; initially aligning an MEMS inertial navigation system; resolving strapdown inertial navigation, and correcting zero speed; carrying out combined navigation of the MEMS inertial navigation system/ satellite navigation receiver/ the Doppler velometer/ the magnetometer/ and the atmospheric pressure altimeter; and displaying the navigation result in real time. The microminiature individual combined navigation system is convenient to individually carry, individual real-time gesture fixing, velocity measurement and positioning can be realized, and whole and precise real-time navigation positioning information can be provided for pedestrians, operating personnel, soldiers, rescue workers and the like in the complex electromagnetic environment.
Owner:NANJING UNIV OF SCI & TECH

Sigma-delta modulated amplifier

A sigma-delta modulated amplifier is disclosed that is operable to sum an input signal and a feedback signal, integrate the summed signal, asynchronously quantize the integrated signal, sample the quantized signal utilizing a pseudo-random osculating signal, and amplify the sampled signal. The amplifier enables discrete implementation of a low-cost, spread spectrum controlled, sigma delta modulated audio amplifier for spectrally pure, high efficiency, low EMI, audio power amplification.
Owner:DOLBY LAB LICENSING CORP

Electric field coupling-based wireless power transmission system

The invention discloses an electric field coupling-based wireless power transmission system. The system comprises a power supply circuit, a high-frequency inverter circuit, a tuning circuit, an electric field coupling polar plate, a rectifier filter circuit and a load circuit and is characterized by also comprising a coupling capacitance detection module, a controller and a fixed frequency drive circuit; a capacitance compensation array is arranged in the tuning circuit; the controller detects parameters of the electric field coupling polar plate and controls compensation values of the capacitance compensation array through the coupling capacitance detection module, and outputs fixed frequency control signals; and the fixed frequency signals are transmitted to the fixed frequency drive circuit, and then the high-frequency inverter circuit is driven to work. The electric field coupling-based wireless power transmission system has the advantages that based on the electric field coupling, the transmission capacity and efficiency of the system are improved by adopting an E amplifier; and by arranging the coupling capacitance detection module, the electric field coupling polar plate of the system is detected in real time, and the capacitance compensation value can be effectively controlled, so that the system is kept in the soft switching state, and the power transmission stability and reliability of the system are improved.
Owner:重庆华创智能科技研究院有限公司

Radio frequency antenna system and high-speed digital data link to reduce electromagnetic interference for wireless communications

A radio frequency antenna system and high-speed digital data link are disclosed to, among other things, reduce electromagnetic interference (“EMI”) at relatively high data rates while reducing the manufacturing complexities associated with conventional data links. In one embodiment, a radio frequency (“RF”) antenna system includes an antenna and an RF radio coupled to the antenna for receiving wireless RF signals. In particular, the RF radio is configured to digitize RF signals at a fixed data rate to form digitized data signals and to apply the digitized data signals at a variable data rate to a high-speed digital link. The variable data rate distributes the signal energy of the digitized data signals over one or more bands of frequencies, thereby beneficially altering an EMI spectral profile describing emissions that develop as the digitized data signals are transported through a channel.
Owner:NVIDIA CORP

Method and equipment of sealed chamber atmosphere deoxygenization and circulating purification for metal 3D printer

The invention discloses a method and equipment of sealed chamber atmosphere deoxygenization and circulating purification for a metal 3D printer. A gas inlet and a gas outlet are respectively formed in two ends of a forming chamber; the gas inlet and the gas outlet are mutually connected through a gas circulating pipeline; a first pneumatic butterfly valve, a dust purifier, a second pneumatic butterfly valve and a water removal drier are arranged on the gas circulating pipeline; a branch pipeline is arranged on the gas circulating pipeline between the second pneumatic butterfly valve and the water removal drier; the tail end of the branch pipeline is connected with a vacuum pump; a molecular sieve and a vacuum pipeline solenoid valve are arranged on the branch pipeline; the forming chamber is connected with an inert gas source. According to the method, firstly the oxygen content in the forming chamber is reduced to a required range before machining, and gas circulating purification is started during machining, so that gas purity degree in the forming chamber is kept; pressure detection and oxygen content detection are introduced, so that the oxygen content and pressure are within a reasonable range at all time during machining. The method and the equipment improve the forming efficiency and quality of the 3D printer, and guarantee the safety and the reliability of the machining process.
Owner:SOUTH CHINA UNIV OF TECH
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