82results about How to "Reduce EMI noise" patented technology

In a switching type power supply for use in an electric arc welder or plasma cutter, of the type having an output transformer with a primary winding in a series circuit DC source with a selected voltage and a switch, either single or tandem, with a conductive on state to pass a current pulse through the primary winding in a first electrical direction and a non-conductive off state disconnecting the DC voltage source from the winding and a large filter capacitor across the DC input voltage source, the improvement comprising: a snubber network for transferring energy due to the leakage inductance of the primary winding to the filter capacitor when the switch is shifted from the on state to the off state where the snubber network includes a storage capacitor with a diode controlled resonant charging circuit so the winding is in a tank circuit with the storage capacitor to charge the storage capacitor in a charging cycle when the switch shifts from the on state to the off state and a diode controlled discharging circuit where the storage capacitor is in series with the winding and the filter capacitor to discharge the storage capacitor into the filter capacitor when the winding reverses polarity.

A technique for effectively attenuating EMI noise, which is generated from the electric power system of semiconductor devices, is described. In accordance with the technique, a power supply netlist with an additional electric current source(s) is generated by adding block power supply current waveform data, as extracted from test vector data and a block netlist, to the power supply netlist as extracted from the layout data of the circuit under analysis. A circuit simulation of the power supply netlist with an additional electric current source(s) is then performed in order to calculate power supply current/voltage waveform data. Furthermore, current/voltage spectral data is calculated by the Fourier transformation of the power supply current/voltage waveform data followed by displaying the current/voltage spectral data as the result of the Fourier transformation.

Disclosed are a three-phase wireless power transfer (WPT) system and three-phase wireless rechargeable unmanned aerial vehicle (UAV) system based on the same. Three power receiving coils, including resonators, are installed at the ends of three landing leg of the UAV. A three-phase power converter installed in the UAV receives the three-phase AC induction current induced in three power receiving coils, including resonators, converting the three-phase AC induction current into a DC current to be charged in a battery. A three-phase power wireless charging apparatus wirelessly transfers three-phase power from three power transmitting coils to the three power receiving coils of the UAV when the three landing legs land on three coil seating units provided on a charging platform. A magnetic flux leakage shielding coil may be provided to prevent magnetic flux leakage from approaching the UAV. The power transfer efficiency is excellent, and electromagnetic interference can be also reduced.

The isolated voltage step-down switching DC-DC converter has one magnetic component, the isolation transformer, and two small size resonant inductors. The transformer is built on a magnetic core with no air-gap, hence no DC storage and thus results in fast load transient response. Two active switches on the primary side have voltage stresses equal to input voltage and two current rectifiers on secondary side have voltage stresses equal to output DC voltage under all operating duty ratio conditions. The converter operates with two independent resonance's, one coinciding with the ON-time interval and the other coinciding with the OFF-time interval resulting in all switches being turned ON and turned OFF at zero current. Primary side high voltage switches operate with zero-voltage switching for all load currents. Despite the two resonance's, the output voltage is controlled by use of the variable duty ratio, constant switching frequency PWM method.

A new type of the passive non-dissipative snubber with a single saturable reactor improves the performance of the boost converter used as a front-end active Power Factor Correction (PFC) in two critical areas: excess voltage stresses caused by high voltage spikes on input high voltage switching transistor of the boost converter is eliminated and EMI noise is much reduced. The high voltage spike energy instead of being dissipated as in a dissipative snubber circuits is recovered resulting in increased conversion efficiency. High voltage spike elimination also allows use of lower voltage rated devices with lower ON resistance, hence further increasing the efficiency of the PFC boost converter.

An inverter for driving a motor includes one or more power stages for producing one or more power signals for energizing the motor, each power stage including first and second III-nitride based bi-directional switching devices connected in series between a DC voltage bus and ground.

A circuit for driving a gate of a power MOS transistor includes an adaptive pull-up unit and an adaptive pull-down unit. The adaptive pull-up unit is connected between a first power source voltage and the gate of the power MOS transistor. The adaptive pull-up unit maximizes pull-up current driving ability. The adaptive pull-down unit is connected between a second power source voltage and the gate of the power MOS transistor. The adaptive pull-down unit maximizes pull-down current driving ability.

The invention presents an antenna element capable of attenuating electric far filed while suppressing attenuation of magnetic near field of electromagnetic field radiated from loop antenna as an application example of antenna element, and a loop antenna and a communication control apparatus of wireless communications medium using the same. The antenna element of the invention comprises a conductor, and a conductive electromagnetic shield disposed on its surface by way of an insulator. The conductive electromagnetic shield has a ground contact, a lead portion, and a plurality of branches, and it is composed so as to determine uniquely the route from an arbitrary point of branches to the ground contact by way of the lead portion.

A second wiring layer 362 of a multilayer wiring board constituting a power converter is provided with a first positive side direct current wiring 311p and a second positive side direct current wiring 312p constituting a direct current bus 300p. The first positive side direct current wiring 311p and the second positive side direct current wiring 312p as well as a negative side direct current wiring are provided with a bent structure for making a transmission path length on one side in a direct current transmitting direction shorter than a transmission path length on other side thereof. Line widths of the first positive side direct current wiring 311p and the second positive side direct current wiring 312p are set to a width equal to or larger than a width by which a damping factor of a noise current in the direct current transmitting direction becomes substantially a constant value.

The invention relates to a distributed transient electromagnetic data acquisition system based on a wireless sensor network. The distributed transient electromagnetic data acquisition system is composed of an industrial personal computer, a coordinator, a plurality of router nodes, a plurality of terminal acquisition nodes and the wireless sensor network serving as a basic network, wherein the router nodes and the terminal acquisition nodes are distributed flexibly. The industrial personal computer is connected with the coordinator through a USB, and the terminal acquisition nodes, the router nodes and all nodes of the coordinator are in wireless connection with one another; the terminal acquisition nodes are used for completing acquisition and uploading of transient electromagnetic data; the router nodes are used for completing the router addressing and data forwarding function; the coordinator is used for completing storage, display and USB communication of the acquired data; the industrial personal computer is used for controlling the acquisition process of each node, displaying the data, and completing calculation of obtained data exploration parameters. The distributed transient electromagnetic data acquisition system has high exploration accuracy, connection wires between the nodes are omitted, field operation is convenient, work efficiency is improved, modular design is adopted for the nodes, and maintenance and replacement are convenient.

An electronic apparatus with a wireless unit includes a multiplier to receive a clock signal at a predetermined frequency. The electronic apparatus further includes a modulator configured to modulate the frequency of the clock signal generated by the multiplier, and a controller configured to change the frequency of the clock signal generated by the multiplier and a modulation rate of the modulation performed by the modulator according to a state of the electronic apparatus.

A motor drive system control provides global closed loop feedback to cooperatively operate system components to adaptively reduce noise and provide noise cancellation feedback. An active EMI filter reduces differential and common mode noise on an input and provides a noise level indication to a system controller. Power switches in both a power converter and power inverter are cooperatively controlled with dynamic dv/dt control to reduce switching noise according to a profile specified by the controller. The dv/dt control is provided as an analog signal to a high voltage IC and codified as a pulse width for a level shifting circuit supplying control signals to the high voltage gate drive. A noise extraction circuit and technique obtain fast noise sampling to permit noise cancellation and adaptive noise reduction.

A turbocharger speed controller includes a rising rate limiter having an input receiving a turbocharger speed signal and an output producing a rate limited turbocharger speed signal, a high envelope filter having an input receiving the rate limited turbocharger speed signal and an output producing a filtered and rate limited turbocharger speed signal, a turbocharger speed control signal generator having an input receiving the filtered and rate limited turbocharger speed signal and an output producing a turbocharger speed control signal based on comparison of the filtered and rate limited turbocharger speed signal with a desired turbocharger speed, and a swallowing capacity control mechanism responsive to the turbocharger speed control signal to vary a swallowing capacity of the turbocharger.

The invention discloses a high-power EMI (Electromagnetic Interference) filter. The high-power EMI filter comprises three phase current output load ends and three phase current input ends, wherein a differential mode inductor L1, a common mode inductor L2 and a common mode inductor L3 are connected between each of the three phase current output load ends and each of the three phase current input ends in series in sequence; the differential mode inductor L1 is connected with a differential mode capacitor C1X and a common mode capacitor C1Y to form a first-order filter; the common mode inductor L2 is connected with a differential mode capacitor C2X and a common mode capacitor C2Y to form a second-order filter; the common mode inductor L3 is connected with a differential mode capacitor C3X and a common mode capacitor C3Y to form a third-order filter; the differential mode capacitors C1X, C2X and C3X are bridged between a phase line and a neutral line; and the common mode capacitors C1Y, C2Y and C3Y are bridged between the neutral line and a ground line. According to the high-power EMI filter, the performance and safety of the filter under high current can be guaranteed, and EMC (Electromagnetic Compatibility) filtering in high-current and high-power systems can be met.

An inductor device includes a first magnetic body pattern layer in which slits are provided and which is made to a pattern, a lower insulating layer formed on the first magnetic body pattern layer, a planar coil layer formed on the lower insulating layer, an upper insulating layer formed on the planar coil layer, and a second magnetic body pattern layer formed on the upper insulating layer and in which slits are provided and which is made to a pattern, wherein the first magnetic body pattern layer and the second magnetic body pattern layer are arranged to intersect orthogonally with the planar coil layer.

The invention efficiently decreases EMI noise occurring with regard to the entirety of an electronic apparatus with a plurality of clocks as references for the operations. The spread spectrum is applied to the clock used by the largest number of ICs, that is, a display clock from among three types of clocks.

Provided are an electric circuit and a display device having the electric circuit. The electric circuit comprises a transmission unit and one or more reception units that perform data frame communications with the transmission unit via a plurality of buses. In the electric circuit, scramble processing is performed during the data frame communications, wherein the scramble processing is performed at different timings for the respective buses with respect to the data frame communication time, whereby the occurrence of EMI noise can be more reliably reduced without increasing the number of components (for example, gaskets).

A planar magnetic element includes a pair of cores, a first winding layer disposed between the pair of cores and including a first winding coupled between a first terminal and a second terminal, and a plurality of second winding layers disposed between the pair of cores and including second windings coupled between a third terminal and a fourth terminal, wherein the first winding layer may be disposed between the plurality of second winding layers.