49results about How to "Improve electromagnetic compatibility characteristics" patented technology

The invention relates to a multi-output power supply, disclosing an adjustable-voltage multi-output power supply, comprising input circuit, transformer and output circuit connected in sequence, where the output circuit comprises main output and at least one auxiliary output, and the auxiliary output comprises auxiliary output transformer winding, rectifier unit and filter unit connected in sequence and an energy delay unit is connected between the transformer winding and filter unit of one or more auxiliary outputs with higher output voltage. Thus, it reduces the output voltage of an auxiliary output by reducing the output energy of the auxiliary output so as to achieve the voltage adjusting purpose.

The invention relates to a self-adaptive driving circuit of an active clamping switch tube in the field of switch power supply. The circuit input terminal Vin and Vss are connected with two ends of anactive clamping signal detection winding Nf of a transformer; the output terminal Gate is connected with the control terminal of the active clamping switch tube; the self-adaptive driving circuit comprises a frequency-voltage conversion control unit, a pulse width control unit, an input pulse current-limiting and shaping unit, a driving circuit unit and a power supply circuit unit that are electrically connected with one another; and the circuit can be also provided with an enabling port and an extended function port. In the invention, the circuit is brief, the cost is low, the circuit is applied to a switch power converter of a flyback quasi-resonant mode and can realize the voltage clamping function; the voltage stress of a main switch tube can be reduced, the electromagnetic noise of the power supply can be reduced, the electromagnetic compatibility characteristic of the power supply can be improved; simultaneously the loss of the clamping circuit can be reduced, the efficiency ofthe power supply can be improved, and the performances of the switch power converter of the flyback quasi-resonant mode are obviously improved.

The invention belongs to the field of medical instruments, and specifically relates to a three-dimensional force transducer used for a minimally invasive medical device. The force transducer includesa flat spring, a groove type outer tube, an inner tube, external optical fibers, a center optical fiber, an upper pedestal and a lower pedestal; the upper and lower ends of the groove type outer tubeare respectively connected to the upper pedestal and the lower pedestal; the outer side of the flat spring is connected to the upper end part of the groove type outer tube; the inner tube successivelypasses through the lower pedestal and the groove type outer tube, the upper end of the inner tube is connected to the inner side of the flat spring, and the lower end of the inner tube is connected to the lower pedestal; the center optical fiber passes through the inner tube, and the two ends of the center optical fiber are respectively connected to the upper pedestal and the lower pedestal; andthe outer surface of the inner tube circumferentially adheres multiple external optical fibers. The force transducer can realize stiffness matching in three-dimensional force direction, and has less length-diameter ratio, so that high precision force detection accuracy can be realized, and the stiffness of operative instruments cannot be excessively weakened; and light can be adopted as a signal acquisition and transmission manner, so that good electromagnetic compatible characteristics can be achieved.

The invention discloses a double-plate linear motion eddy current retarder, and belongs to the technical field of spacecraft on-track micro-vibration control. The double-plate linear motion eddy current retarder comprises a center shaft, a spring, a mounting cylinder, an outer cylinder, a first metal plate, a permanent magnet, a connecting shaft, a second metal plate, a magnetic shielding end cover and a magnetic shielding cylinder; the bottom of the mounting cylinder is fixed at the end part of the outer cylinder; a linear bearing is mounted in the mounting cylinder; the center shaft is sleeved in the linear bearing; the spring coats the mounting cylinder; the magnetic shielding cylinder is fixed in the outer cylinder; the magnetic shielding end cover is mounted at an opening end of the magnetic shielding cylinder; the permanent magnet is mounted in a closed space consisting of the magnetic shielding cylinder and the magnetic shielding end cover; after the connecting shaft penetrates through the permanent magnet, the top end of the connecting shaft is connected with the tail end of the center shaft; the first metal plate and the second metal plate are respectively fixedly connected to the two ends of the connecting shaft, and are respectively positioned at two ends of the polarization direction of the permanent magnet. The double-plate linear motion eddy current retarder is applied to the spacecraft on-track micro-vibration control, uses an electromagnetic induction principle for generating damping, and can adapt to such complex environments as high space vacuum and thermal alternation.

The invention discloses a microcontroller used for improving the electromagnetic compatibility characteristic of an automobile electronic control system. A multi-mode clock generation module and an IO port module are improved, a clock gating method is applied to the multi-mode clock generation module, the electromagnetic compatibility characteristic of the IO port module is reinforced with a turning rate and driving strength control method, and the electromagnetic compatibility characteristic of the automobile electronic control system is effectively improved. The microcontroller used for improving the electromagnetic compatibility characteristic of the automobile electronic control system has the advantages of being simple in structure and high in adaptability, clocks and ports which are applied to an automobile electronic MCU are rich in configuration function, different working modes and using characteristics can be configured according to the requirement of the system, all the independent peripheral clocks can be subjected to gating setting, the functions of open-drain setting, upward and downward pull, digital / analog function multiplex, interrupt multiplex, EMC control and the like are integrated on the ports, and high flexibility and high configurability are achieved.

The invention discloses a high-efficiency low-ripple frequency conversion modulation method, and belongs to the technical field of power transmission. An inverter composed of two high-frequency switching devices and six low-frequency switching devices is driven, the generation mode and time sequence of a zero vector in a traditional space vector modulation strategy are improved, the high-frequencyswitching devices control bus voltage to be zero to replace the zero voltage vector, meanwhile zero voltage switching conditions are provided for the low-frequency switching devices, the low-frequency switching device only generates an effective voltage vector, the switching action frequency is reduced, and the loss of the inverter is reduced by utilizing the low switching loss characteristic ofthe high-frequency switching device, so that the available switching frequency of the inverter is improved, the current ripple is reduced, the carrier period is adjusted in real time according to thepredicted value and the given value of the current ripple, the current ripple is reduced, and the electromagnetic compatibility of the system is improved, according to the modulation algorithm provided by the invention, higher system working efficiency, lower current ripple output and higher current control precision can be obtained at the same time, and the modulation algorithm has a certain application value.

The invention discloses a drawing circuit for resistance in photovoltaic grid-connected inverter direct current side noise source and a method. The drawing circuit comprises a direct current voltage source, a signal source, a current probe, a spectrum analyzer and a grid-connected inverter. A negative pole on the direct current side of the grid-connected inverter is connected with the signal source through a radio frequency cable. The signal source is connected to a negative pole of the direct current voltage source. A positive pole of the direct current voltage source is connected with a positive pole on the direct current side of the grid-connected inverter through a wire. Single current probe is arranged on the wire. The single current probe is connected to the spectrum analyzer. According to the fact that high-frequency noise signal voltage in a circuit detection circuit is drawn, resistance of the photovoltaic grid-connected inverter direct current side noise source and in a conduction electro-magnetic interference (EMI) frequency range (150KHz to 30 MHz) can be effectively drawn through the fact that high-frequency signal output frequencies of the signal power source are changed one by one. According to the drawing circuit for the resistance in the photovoltaic grid-connected inverter direct current side noise source, the conduction EMI noise characteristic analysis on the direct current side of the photovoltaic grid-connected inverter and design of an EMI filter are guided, and an effective theory solution is provided for solving of the problems of the conductive EMI on the direct current side of the photovoltaic grid-connected inverter.

The invention discloses a preparation method of an excessive zinc-doped ferrite solid waste-based electromagnetic wave absorption material. From the perspective of a ferrite crystal structure, throughdisplacement doping of excessive zinc atoms, more Fe<3+> can at site A in spinel structure ferrite can enter site B under the driving of Zn<2+>, the molecular magnetic moment is increased, and the response of magnetic moment to electromagnetic wave is greatly enhanced, thus improving the magnetic loss performance of low-loss magnetic core solid waste, balancing the magnetic loss difference between different mixed solid wastes, and acquiring the high performance broadband electromagnetic wave absorption material and device. The method provided by the invention has the characteristics of simpleoperation, short production period and low requirement for equipment hardware, the electromagnetic wave absorption material can be widely popularized in electromagnetic shielding, electromagnetic interference resistance, electromagnetic radiation resistance and other uses of various electronic and electrical and wireless communication equipment, has excellent low-frequency-band electromagnetic wave absorption performance, and has very wide application.

The invention provides a DC transformer calibrator and a working method thereof. The calibrator comprises a first digital multimeter for collecting a first standard analog signal of a standard DC transformer or a second standard analog signal of the standard DC transformer; a second digital multimeter for collecting an analog signal to be calibrated of a DC transformer to be calibrated; a GPIB acquisition card for collecting the first standard analog signal and the analog signal to be calibrated, or collecting the second standard analog signal; a protocol converter for converting the collecteddigital signal of an FT3 protocol into sampling data to be calibrated of a TCP / IP protocol; and a PC industrial computer for determining steady-state errors of an analog-output type DC transformer according to the first standard analog signal and the analog signal to be calibrated, or determining steady-state errors of a digital-output type DC transformer according to the second standard analog signal and the sampling data to be calibrated. The technical scheme above realizes calibration of the analog-output type and digital-output type DC transformers.

The invention provides a power module, comprising a gallium nitride power switch and a drive circuit. The gallium nitride power switch comprises a drain, a source and a gate. The drive circuit comprises an input end and an output end. The output end of the drive circuit is electrically coupled with the gate of the gallium nitride power switch through an external resistor and is used for changing acurrent of the gate of the gallium nitride power switch by adjusting a resistance value of the external resistor, thereby controlling switch-on or switch-off speed of the gallium nitride power switch. According to the power module provided by the invention, the current of the gate of the gallium nitride power switch is adjusted through utilization of the resistance value of the external resistor,further the switch-on or switch-off speed of the gallium nitride power switch is adjusted, the electromagnetic compatibility of a terminal product is improved, and the performance of the gallium nitride power switch is improved.

The invention discloses an optically controlled polarization-reconfigurable monopole antenna. The optically controlled polarization-reconfigurable monopole antenna comprises a reflecting plate and a dielectric substrate, the dielectric substrate is fixed to the position above the reflecting plate through supporting structures, an antenna radiation unit, a parasitic unit, a microstrip line feed unit and optical switches are printed on the upper surface of the dielectric substrate, and an earth plate unit is printed on the lower surface of the dielectric substrate; the antenna radiation unit comprises a C-shaped monopole, and the C-shaped monopole is provided with a groove and L-shaped grooves; the parasitic radiation unit is located in the groove, and the optical switches are located at thejunction of the microstrip line feed unit and antenna radiation unit; and the optically controlled polarization-reconfigurable monopole antenna further comprises a coaxial feeder line unit, and the coaxial feeder line unit feeds electricity to the microstrip line feed unit through the dielectric substrate. The optically controlled polarization-reconfigurable monopole antenna is of a planar structure, radiates directionally by using the reflecting plate, has good directionality and can achieve a polarization-reconfigurable effect in three modes.

The invention relates to an antenna fixing structure of a magnetron for a microwave oven. The antenna fixing structure comprises an antenna and blades arranged inside the positive electrode portion of the magnetron. The upper end of the antenna and the central shaft of the positive electrode portion of the magnetron are arranged coaxially; the upper end of the antenna passes through an antenna sealing cover and a ceramic ring of the magnetron and is connected with an upper sealing portion of an exhaust pipe. And the lower end of the antenna bends towards the outer side of the central shaft of the positive electrode portion and is fixedly with the blades mutually; and the distances between the inner sides of the blades and the antenna lower end and the blade fixing positions are increased by 10 to 15%. Because the fixing position of the antenna lower end is farther off the central shaft of the positive electrode portion of the magnetron, the electromagnetic compatible characteristic of the magnetron for the microwave oven can be improved under the circumstances that the magnetron characteristic remains unchanged, thereby reducing the secondary harmonics well.

The invention discloses a microcontroller used for improving the electromagnetic compatibility characteristic of an automobile electronic control system. A multi-mode clock generation module and an IO port module are improved, a clock gating method is applied to the multi-mode clock generation module, the electromagnetic compatibility characteristic of the IO port module is reinforced with a turning rate and driving strength control method, and the electromagnetic compatibility characteristic of the automobile electronic control system is effectively improved. The microcontroller used for improving the electromagnetic compatibility characteristic of the automobile electronic control system has the advantages of being simple in structure and high in adaptability, clocks and ports which are applied to an automobile electronic MCU are rich in configuration function, different working modes and using characteristics can be configured according to the requirement of the system, all the independent peripheral clocks can be subjected to gating setting, the functions of open-drain setting, upward and downward pull, digital / analog function multiplex, interrupt multiplex, EMC control and the like are integrated on the ports, and high flexibility and high configurability are achieved.

The invention discloses a preparation method of ferrite solid waste-based electromagnetic wave absorbing material doped with excess zinc. Starting from the perspective of ferrite crystal structure, the spinel structure iron can be made through the substitution doping of excess zinc atoms Fe at the A site in the oxygen body 3+ in Zn 2+ Driven by the drive, more enter the B position, increase the molecular magnetic moment, greatly enhance the response of the magnetic moment to electromagnetic waves, thereby improving the magnetic loss performance of the low-loss magnetic core solid waste, and balancing the magnetic loss difference between different mixed solid waste , to obtain high-performance broadband electromagnetic wave absorbing materials and devices. The invention has simple operation, short production cycle and low requirements on equipment hardware, and can be widely used in electromagnetic shielding, anti-electromagnetic interference, and anti-electromagnetic radiation of various electronic and electrical and wireless communication equipment, and has excellent low-frequency electromagnetic wave absorption performance , is widely used.

An exhaust pipe for a magnetron used in a microwave oven, comprising a tubular body and a fixed wall extending outward from the outside of the pipe body and bending downwards, the exhaust pipe is arranged above the antenna cover of the magnetron On the ceramic ring, and the lower part of the ceramic ring is fixed with the antenna cover, the top of the tube body is sealed after vacuuming, and the length of the tube body is reduced by 20‑25% after sealing; the lower end of the fixed wall extends to the farthest plane and the tube The distance between the planes where the lowest point of the body lies is reduced by 18‑21%. By changing the reserved length of the upper end of the pipe body and the length of the lower end of the pipe body protruding from the fixed wall, the choke capacity of the exhaust pipe for the third harmonic and the fourth harmonic is improved, and the useless high noise generated during the operation of the magnetron is correspondingly suppressed. Frequency harmonics, without causing changes in the characteristics of the magnetron, improve the electromagnetic compatibility characteristics of the magnetron used in microwave ovens.

The invention provides a semi-directional adjusting circuit, which is used for adjusting output signals of at least an auxiliary circuit of a signal source. The semi-directional adjusting circuit includes a transformer having at least two windings. An output main circuit of the signal source is in series with a first winding of the transformer; the auxiliary circuit requiring signal adjustment is in series with at least the other winding of the transformer. By adopting the technique of the semi-directional adjusting circuit provided by the invention, the voltage adjusting amplitude can be large without loss increase, and thus the invention is beneficial for increasing power efficiency and also the reliability. The semi-directional energy consumption can be controlled through the duty cycle of main circuit adjustment, which is free from the limit by a relatively high quantity or a relatively low quantity of specific output of the auxiliary circuit. The invention can realize complete compensation under the condition that the output of all the auxiliary circuits is relatively low. The voltage adjusting amplitude can be directly used for quantum calculation, without effect from the duty cycle. Besides, the voltage adjusting cost is low, the performance cost ratio is high, and the electromagnetic characteristics of relevant output circuits can be improved as well.

The invention discloses a multiple output supply, comprising a transformer provided with at least two output paths, a power control module for controlling the input of the transformer, and a voltage detecting comparison module. The voltage detecting comparison module detects an output voltage of a certain output path in a plurality of output paths except a main output path provided with feedback,and outputs the detecting result to the power control module; the power control module can start up the protection according to the detecting result. The invention further comprises a mutual-inductance element, wherein the mutual-inductance element is in series connected to a detecting output path which is connected with a voltage detecting module and at least one output path of the multiple output supply respectively. The circuit of the invention is very simple, complicated circuits, such as reference source and comparator, are not needed, and the parts that can bring depletion such as resistance are not required.

The invention discloses a multi-path output power supply, comprising a transformer having at least two output paths, a power supply control module and a voltage detection comparing module. The at least two output paths comprise a main output path and an assistant output path. The output end of the power supply control module is connected to the input end of the transformer through the switch pipe. The output end of the voltage detection comparing module is connected to the input end of the power supply control module; further comprising a mutual inductor comprising a detecting winding connected to one input end of the voltage detection comparing module and an output path winding connected in series to at least two output paths. The circuit of the invention is extremely simple without complex circuits, for example, reference source, and comparator and without adding apparatus such as resistor which brings loss. The invention not only processes overcurrent or short-circuit protection simultaneously for multi-path output, but also processes overcurrent protection for the main output path and all assistant output paths simultaneously.