402results about How to "Reduce electromagnetic noise" patented technology

A system for detecting unconfined-plasma events in a plasma processing chamber is disclosed. The system may include a sensor disposed in the plasma processing chamber for providing a current when unconfined plasma is present in the plasma processing chamber. The system may also include a converter for converting the current into a voltage and a filter for removing noise from the voltage to provide a first signal. The system may also include a detector for determining presence of the unconfined plasma using an amplified level of the first signal and / or the first signal. The system may also include a conductor for coupling the sensor and the converter to conduct the current from the sensor to the converter. The system may also include a shield for enclosing at least a portion of the conductor to at least reduce electromagnetic noise received by the conductor.

A mobile station (100) that includes a processor (212) that selectively disables at least one station component to reduce electromagnetic noise generated by the station in the frequency range below 20 kHz when the mobile station is operated in the hearing aid compatible mode. The component can be, for example, a display (204), a light (206) or a wireless interface (208). The processor also can optimize characteristics of audio signals transmitted from the mobile station to the hearing aid for reproduction by the hearing aid. For instance, the processor can selectively adjust filter parameters (216) and / or a signal gain (218) applied to audio signals. A user interface (220) having a soft-key can be provided to cycle through various HAC options.

In a semiconductor module according to certain aspects the invention, a U-terminal and an M-terminal overlap each other in a manner to reduce inductance and to further to reduce the size of snubber capacitor. In certain aspects of the invention, a P-terminal, M-terminal, N-terminal, and U-terminal are arranged such that the U-terminal, through which currents flow in and out, is arranged farthest away from control electrodes to reduce the noises superposed to control electrodes, and the P-terminal, M-terminal, N-terminal, and U-terminal are aligned to facilitate attaching external connection bars thereto. A power semiconductor module according to aspects of the invention can facilitate reducing the wiring inductance inside and outside the module, reducing the electromagnetic noises introduced into the control terminals, and attaching the external wirings to the terminals thereof simply and easily.

An electrical connector structure includes an insulating body, ground terminals, and a grounding piece. The insulating body has a divider block. The ground terminals are fixed on the insulating body and arranged in two opposite sides of the divider block. Each ground terminal has a docking portion, a main portion, and a tail portion. The main portions are fixed on the insulating body. The docking portions and the tail portions extend from two sides of the insulation body. The grounding piece is fixed on the divider block. The grounding piece has a first mounting plane and a second mounting plane corresponding to the first mounting plane. The first mounting plane and the second mounting plane are located at two opposite surfaces of the divider block, and have contact portions protruding therefrom. The contact portions electrically contact the ground terminals respectively.

There is described a multi-layer printed circuit board and a method of installing it. The circuit board includes a first signal layer formed on its obverse surface; a ground layer arranged at a position next to the first signal layer; an electronic power source layer arranged at a position next to the ground layer; and a second signal layer formed on its reverse surface. The first and second patterns are formed around peripheral areas of the first and second signal layers, respectively. The first ground pattern and the second ground pattern are electrically coupled to each other by plural through holes, and the multi-layer printed circuit board is installed on an electro-conductive housing in such a manner that a substantially whole area of the second ground pattern electrically contacts a mounting area of the electro-conductive housing, the mounting area being an electro-conductive area continuously coupled to the electro-conductive housing.

When a PWM signal generating unit (10) sets a duty D of a PWM signal based on command signals (10c), the PWM signal generating unit (10) sets a phase difference φ between each of the PWM signals based on a relation formula of φ (degree)=360 (degree)×D (%) / 100 (%), and generates and outputs first PWM signals (10a) and second PWM signals (10b) in which the duty is D (%) and the phase difference is φ (degree). The first PWM signals (10a) and the second PWM signals (10b) are respectively supplied to a first load driving circuit (21) and a second load driving circuit (22) to operate a first motor fan (3) and a second motor fan (4) by a PWM control, respectively.

A DC brushless fan motor driving circuit has a Hall PWM signal generator, a speed signal generator, a PWM driver and a full-bridge switching circuit. The Hall PWM signal generator obtains a Hall sine wave signal from an external Hall sensor and converts the Hall sine wave signal to a varied Hall PWM signal. The speed signal generator is connected to an external PWM input signal to set speed of a fan motor and a low speed voltage to determine a present speed setting signal. The speed signal generator further obtains the varied Hall PWM signal to compare the present speed setting signal to generate a SPWM signal to the PWM driver. The PWM driver outputs a SPWM signal to the full-bridge switching circuit and then coil current is formed close to a sine wave signal to decrease the electromagnetic noise.

In a rotating electric machine that is formed of a distribution winding motor with two slots per each pole and each phase, a stator core includes an air gap of a constant width dg1 between the leading end of a same-phase-intermediate tooth and the outer circumferential face of a rotor core, and an air gap of a width not uniform in the circumferential direction between the leading end of a different-phase-intermediate tooth and the outer circumferential face of the rotor core, with a width dg2 (>dg1) as the largest value. A magnetic circuit having a magnetic resistance higher than that of the same-phase-intermediate tooth is formed at the different-phase-intermediate tooth. By establishing a difference in the width of the air gap such that the number of flux linkages at the different-phase-intermediate tooth reduced by the increased magnetic resistance is substantially equal to the number of flux linkages at the same-phase-intermediate tooth, the electromagnetic excitation applied in directions opposite to each other acquire balance so as to cancel each other, allowing vibration at the stator core to be suppressed.

Slots are formed at a nonuniform pitch at a ratio of two slots per phase per pole. An X-phase winding phase portion constituting a stator winding is constructed by connecting in series an a-phase winding phase sub-portion and a d-phase winding phase sub-portion having a phase difference corresponding to an electrical angle of 34 degrees, a Y-phase winding phase portion is constructed by connecting in series a b-phase winding phase sub-portion and an e-phase winding phase sub-portion having a phase difference corresponding to an electrical angle of 34 degrees, and a Z-phase winding phase portion is constructed by connecting in series a c-phase winding phase sub-portion and an f-phase winding phase sub-portion having a phase difference corresponding to an electrical angle of 34 degrees.

A stator winding is prepared by inserting U-shaped conductor segments into pairs of slots from a first end surface end of a stator core and welding together end portions of the conductor segments projecting outward at a second end surface end of the stator core. Joint portions between the end portions of the conductor segments are arranged into two rows in an annular shape in a circumferential direction at the second end surface end of the stator core. A first electrically-insulating layer is formed by applying an epoxy resin so as to cover each of the joint portions and to bridge radially-adjacent pairs of the joint portions. A second electrically-insulating layer is formed by applying a silicone resin so as to cover the first electrically-insulating layer and to extend to an electrically-insulating coating on the conductor segments.

The invention discloses an air gap adjustment assembly method of a wind power generator. The method comprises the following steps of: (A), designing clearance fit of spigots of a seat and front and rear end covers; (B), by uniformly selecting detection points at the front and rear ends of a stator (2) and a rotor (4), measuring an air gap value between the stator and the rotor; (C), according to the air gap value, adjusting an adjusting bolt, and uniformizing an air gap; and (D), drilling conical pin holes in joints of the end covers and the seat (1), positioning by using conical pins (14), and finishing assembly. The invention also discloses a structure of the wind power generator which is assembled by using the method. The invention has the advantages that the air gap uniformity of the generator is easily, conveniently and quickly adjusted, the phenomenon of air gap non-uniformity in the machining and motor assembly process can be quickly eliminated, one-sided magnetic pull which isgenerated by air gap non-uniformity of the stator and the rotor is effectively eliminated or reduced, vibration noise and electromagnetic noise are reduced, friction between the stator and the rotor is avoided, and the operating reliability of the generator is improved.

The invention relates to a control method for a bidirectional quasi-Z-source inversion type motor driving system. The control method comprises the following steps of collecting the voltage of a capacitor C2 and the current of a permanent magnet synchronous motor; obtaining voltage components of a d axis and a q axis; obtaining a direct-connection duty ratio; carrying out an SVPWM (space vector pulse width modulation) algorithm by inserting the direct-connection duty ratio according to the voltage components of the d axis and the q axis and the direct-through duty ratio to obtain six paths of PWM control signals for controlling the on and off of three-phase bridge arms of a three-phase bridge type inverter; and carrying out logic calculation on the six paths of PWM control signals to output a PWM control signal for controlling the on and off of an IGBT switch tube S7. Compared with the prior art, the average direct-connection duty ratio and the capacitor voltage closed loop control closed loop policy are added to the conventional SVPWM control method, so that the direct current side voltage has the voltage boosting capability; and on the basis, the power switch S7 which is complementary with the direct-connection state is further designed, so that the bidirectional flow of energy can be realized.

An IGBT having a trench gate structure is disclosed which generates decreased noise at switching and displays superiority in saturation voltage to turn-off loss characteristics (trade-off characteristics). In a part of a region on an emitter side surface interposed between trench gates, a sub well region is provided, which is connected to an emitter electrode through diodes. When the IGBT is in a turned-on state, the diodes are brought into a non-conduction state to isolate the sub well region from the emitter electrode, by which carriers are accumulated. When the IGBT is in a turned-off state, the diodes are brought into a conduction state to electrically connect the sub well region to the emitter electrode, by which carriers are discharged at a high speed. In an early stage of turning-on of the IGBT, capacitance of a portion of the gate facing the sub well region is converted to gate-emitter capacitance to thereby reduce gate-collector capacitance, by which electromagnetic noise at switching is reduced.

There is provided an alternating current generator comprising: a rotatably supported field rotor having a pair of opposed rotor pole cores, each being provided with P / 2 claw poles wherein P is an even number, and a field winding wound on the rotor pole cores; an armature core located around the outer periphery of the field rotor and having axially extending 3nP slots wherein n is an integer more than one; n independent sets of three-phase windings, each being wound on the armature core by being inserted in the slots so that the n sets of three-phase windings are shifted from each other by electrical angle of .pi. / (3n) radians; and three-phase rectifiers connected with the n sets of three-phase windings to rectify output voltages generated by the three-phase windings.

There are described headphones comprising earcups to be placed about ears of a user, with a headband linking the earcups and to be extending above a head of the user. A flexible band distinct from the headband is secured below the headband for contact with the head of the user. Removable headband sensors are embedded in the flexible band and have a portion thereof protruding downwardly from the flexible band to reach the scalp. The flexible band has a flexibility which makes the flexible band deform under the weight of the earcups to conform with the head of the user to ensure high quality contact between the headband electrodes and the scalp. There are further provided earcup electrodes on the earcups for contact with a region on or behind an ear of the user. Signals from the electrodes can be used for different purposes such as concentration monitoring and feedback.

An IGBT having a trench gate structure is disclosed which generates decreased noise at switching and displays superiority in saturation voltage to turn-off loss characteristics (trade-off characteristics). In a part of a region on an emitter side surface interposed between trench gates, a sub well region is provided, which is connected to an emitter electrode through diodes. When the IGBT is in a turned-on state, the diodes are brought into a non-conduction state to isolate the sub well region from the emitter electrode, by which carriers are accumulated. When the IGBT is in a turned-off state, the diodes are brought into a conduction state to electrically connect the sub well region to the emitter electrode, by which carriers are discharged at a high speed. In an early stage of turning-on of the IGBT, capacitance of a portion of the gate facing the sub well region is converted to gate-emitter capacitance to thereby reduce gate-collector capacitance, by which electromagnetic noise at switching is reduced.

A mobile station (100) that includes a processor (212) that selectively disables at least one station component to reduce electromagnetic noise generated by the station in the frequency range below 20 kHz when the mobile station is operated in the hearing aid compatible mode. The component can be, for example, a display (204), a light (206) or a wireless interface (208). The processor also can optimize characteristics of audio signals transmitted from the mobile station to the hearing aid for reproduction by the hearing aid. For instance, the processor can selectively adjust filter parameters (216) and / or a signal gain (218) applied to audio signals. A user interface (220) having a soft-key can be provided to cycle through various HAC options.

The invention provides a converter controllable in regenerative running mode, which is a power converting apparatus capable of suppressing harmonics without increasing the size of a reactor, and reducing power loss and electromagnetic noise. A power converter (7) is configured by directly connecting AC sides of single-phase sub-converters (3) having a DC voltage lower than a DC voltage of a 3-phase main converter (2) to AC input lines of individual phases thereof in series. The main converter (2) is driven by one gate pulse per half recurring cycle and a voltage produced by each sub-converter (3) at AC terminals thereof is controlled to match a difference between an AC power supply voltage and a voltage produced by the main converter (2) at AC terminals thereof, whereby phase voltages of the power converter (7) are generated as the sums of phase voltages of the individual converters (2), (3).

The invention relates to a brushless DC (Direct Current) motor for unmanned air vehicles, belonging to the technical field of unmanned air vehicle powerplants. The brushless DC motor comprises an external rotor composed of a rotor end cover, a rotor yoke and a permanent magnet, a stator composed of a winding, a stator iron core and a stator yoke, an upper bearing, a lower bearing, a rotation shaft and a stopper ring, wherein the outer diameter of the rotor yoke is the same as that of the rotor end cover, the rotor yoke is fixed at the lower end of the rotor end cover, the permanent magnet is fixed on the inner wall of the rotor yoke, and the number of magnetic poles of the permanent magnet is 24; the stator iron core comprises 18 slots, the stator yoke is sleeved on the inner wall of the stator iron core, and the winding is coiled on the outside of the stator iron core; the upper bearing and the lower bearing are respectively fixed on two ends of the rotation shaft; the stator is connected with the rotor through the rotation shaft, the stator is embedded inside the rotor end cover, and the stopper ring is sleeved on the rotation shaft. In the invention, by directly driving airscrews, the brushless DC motor is beneficial to elimination of efficiency loss of a driving system, and improvement of lift force / power consumption ratio and lift force / mass ratio of air vehicles.

A wire harness includes an electric wire, a braided shield covering the electric wire, an annular electromagnetic wave absorption component that includes a through-hole for inserting electric wire and absorbs electromagnetic wave emitted from the electric wire, and a movement-restricting member for restricting the electromagnetic wave absorption component from moving in a direction of inserting the electric wire in the through-hole.

A cable holding structure includes a shielded cable that includes a center conductor and a shield conductor on an outer periphery of the center conductor, and a holding portion being electrically conductive, provided on a flat plate portion and configured to hold the shielded cable. The holding portion includes a through-hole aligned in a direction intersecting with the flat plate portion. The shielded cable is held by the holding portion such that at least the center conductor is enclosed in the through-hole and the shield conductor is electrically connected to the conductive holding portion.

The invention discloses a motor with a slotless amorphous iron alloy radial magnetic circuit. A stator core (21) is wound into a cylinder by an amorphous iron alloy strip; a stator winding (22) is wholly cylindrical and is fixed on a cylindrical surface in the stator core (21); a metal reinforced bushing (25) is fixed on an inner wall of the stator winding (22); and a radial air gap (5) is formed between an inner hole of the stator winding (22) and an outer surface of a rotor (3). A rotor core (31) is made of an amorphous iron alloy material to form a hollow columnar structure; a key slot (312) which is connected with a motor shaft (6) is formed on an inner hole wall; a radial outer surface of the key slot (312) is matched with a permanent magnet (32); and the permanent magnet (32) is embedded in or sleeved on an outer surface of the rotor core (31) for fixation. The motor effectively reduces the volume, reduces the loss, improves the efficiency, simultaneously avoids processing difficulty of slots, saves working hours, greatly reduces the processing cost, eliminates motor slot effect, reduces electromagnetic noise, has the advantages of low eddy-current loss, excellent high-frequency characteristics and high power density, and is a high-efficiency and energy-saving motor.

The invention relates to an intelligent heating agitator and the controlling method, which is applied in heating and agitating experiment in chemical field, especially dangerous chemical experiment and reacting in sealed container. The method comprises: (1) agitating with magnetic drive, isolation of driver and agitator is favor for sealing reacting container and preventing reactant from splashing; (2) putting intelligent controller far away from reacting device, remote controlling to avoid contact with toxic substance; (3) controlling coil and heating plate with intelligent H bridge and power device, which is characterized by smaller volumn and higher stability; (4) integrating agitator with heating device, and the agitating speed, mode, heating temperature are controllable; (5) rotating magnetic field by changing current direction in coil, which is characterized by simpler mechanical structure and flexible control.

The invention provides equipment and method for detecting the temperature coefficient of remanence. The equipment comprises a rotating device for a sample to be detected, a temperature control device, a magnetic flux detecting device and a device for computing the temperature coefficient of the remanence. The rotating device for the sample to be detected is used for rotating the sample to be detected; the temperature control device is used for changing and stably maintaining the temperature of the sample to be detected; the magnetic flux detecting device is used for detecting different magnetic fluxes generated by different magnetic fields of the sample to be detected due to different temperatures while the sample to be detected is rotated; and the device for computing the temperature coefficient of the remanence is used for computing the temperature coefficient of the remanence of the sample to be detected according to the different magnetic fluxes corresponding to the different temperatures, detected by the magnetic flux detecting device. Therefore, the temperature coefficient of open-circuit remanence of permanent magnet materials with high signal to noise ratio can be obtained.

The invention discloses an improved main circuit structure of a photovoltaic synchronization inverter. The improved main circuit structure comprises a photovoltaic (PV) battery board, a capacitor Cin, distributed capacitors C1 and C2, a non-isolation direct-current / direct-current (DC / DC) converter, a capacitor C, an H bridge consisting of power switching devices V1, V2, V3 and V4, and diodes D1, D2, D3 and D4 which correspond to one another one to one, an afterflow loop on the voltage positive half circle of a power grid consisting of a power switching device V5 and diodes D5 and D7, an afterflow loop on the voltage negative half circle of the power grid consisting of a power switching device V6 and diodes D6 and D8, a filter circuit consisting of inductors Lf1 and Lf2 and a capacitor Cf,and a common mode resistant voltage filter H-bridge capacitor group consisting of capacitors C3, C4, C5 and C6. A synchronization inversion circuit for executing the improved main circuit structure has the advantages of capability of effectively restraining common mode voltage / current, high inversion efficiency, small volume, light weight, low electromagnetic noise and the like.

The invention discloses a startup control system for a PG speed regulating motor. The startup control system comprises a rotating speed detector, a rotating speed feedback module, a motor drive conversion module and a controller, wherein the rotating speed detector is used for detecting the rotating speed of the PG speed regulating motor in real time; the rotating speed feedback module is connected with the rotating speed detector; the motor drive conversion module is connected with the PG speed regulating motor and a positive electrode of inputted alternating current; the controller is used for outputting a control signal to the motor drive conversion module so as to enable the PG speed regulating motor to be started after first effective voltage is obtained; the controller is respectively connected with the rotating speed feedback module and the motor drive conversion module; when the rotating speed of the PG speed regulating motor is larger than first preset rotating speed, the controller is used for regulating the control signal to adjust the rotating speed of the PG speed regulating motor. According to the startup control system, the low-frequency electromagnetic noise can be reduced in the quick startup of the PG speed regulating motor, and the overshoot phenomenon in the startup process of the PG speed regulating motor is prevented. The invention further discloses a startup control system for the PG speed regulating motor.