31 results about "Line Impedance Stabilization Network" patented technology

An electro-magnetic interference detecting system for power line conduction is provided. The electro-magnetic interference detecting system for the power line conduction comprises an electro-magnetic interference (EMI) receiver, a line impedance stabilization network (LISN), a current probe, a voltage probe, an impedance analysis meter and an oscilloscope, wherein the EMI receiver, the LISN, the current probe, the voltage probe, the impedance analysis meter and the oscilloscope are sequentially connected to form a system. The electro-magnetic interference detecting system for the power line conduction is simple and convenient and reliable in the detection process, and facilitates operation of technicians.

The invention discloses a measuring device of switch power supply EMI noise source internal impedance that comprises line impedance stabilization network, common mode/differential mode impedance test module, signal generator and spectrum analyzer; power cord is directly input to the line impedance stabilization network, passes the common mode/differential mode impedance test module, and then input to the switch power supply and load to construct a whole power circuit; the signal generator provides a input signal for the common mode/differential mode impedance test module, response signal in the module is detected by the spectrum analyzer. The measuring method of switch power supply EMI noise source internal impedance IA also disclosed. The measuring device and method can measure the all-purpose internal impedance for all kinds of noise source, but also measure the unknown impedance, the accuracy is high and the operation is simple. The measuring method can judge the nature of internal impedance and provide a precondition for designing of EMI filter that is the designing of filter fulfills the impedance matching property of filter.

The invention discloses a low-voltage orthogonal frequency division multiplexing (OFDM) carrier physical layer communication performance detecting system which is used for detecting emission performance indexes and receiving performance indexes of a low-voltage OFDM carrier physical layer. The detecting system comprises a signal isolation device, a standard carrier sending device, a carrier to be detected sending device, a carrier to be detected receiving device, a standard 50 omega impedance power network, a coupling circuit, two mixers, two adjustable attenuators, a white gaussian noise generator, a line impedance stabilizing network, a programmable logic controller (PLC) demodulation device, an alternating current power meter, a 220V alternating current power source, a signal generator, a network analyzer, a spectrum analyzer, a channel simulator, a signal analyzer and a computer. According to the technical characteristics of low-voltage power line carrier communication of an OFDM modulation mode, the detecting system is capable of conducting detailed test to the main performance indexes of the communication mode, the testing process is speedy, system conformability is high, system manufacturing cost is low, and space and labor cost are saved.

A line impedance stabilization network (LISN) able to withstand high currents includes a power port for connecting to a power supply, an equipment under test (EUT) connection port for connecting to an EUT, and a first inductor connected between the power port and the EUT connection port. The coil includes a first end, an opposite second end, a coiled wire connected between the first end and the second end, and a first and a second resistor. The wire includes a plurality of coils, and the first and second resistors bridge between the starting coil (in each direction) of the coil of wire and two inboard coils of the coil of wire.

The invention relates to a module for separating a different-mode signal and a common-mode signal. The module comprises a first transmission-line transformer. The two ends of a first transmission-line transformer primary coil are connected with the firing line output terminal and the null line output terminal of a line impedance stabilizing network respectively, the first transmission-line transformer primary coil is connected between the firing line output terminal and the null line output terminal, a center tap is arranged in the middle of the primary coil, the center tap is grounded through a first resistor, the center cap is connected with a common-mode signal output terminal, the firing line output terminal is further connected with one end of the input end of a second transmission-line transformer, the corresponding output end of the second transmission-line transformer is connected with a different-mode signal output terminal through a second resistor, the null line output terminal is further connected with the other end of the input end of the second transmission-line transformer, and the corresponding output end the second transmission-line transformer is grounded. The module has the advantages of being simple in circuit structure, good in common-mode rejection ratio and different-mode rejection ratio, precise in test effect, small in size, light in weight and the like.

An electromagnetic interference (EMI) test system with self-checking function for detecting electromagnetic interference includes a signal source, a line impedance stabilization network (LISN), a coupling decoupling network (CDN), an impedance stabilization network (ISN) and a receiver. The signal source provides an electronic signal, the LISN separates interference signal from the electronic signal. The CDN outputs a coupling signal, and the ISN separates interference signal from the signal from the CDN. The receiver figures out current signal strength of each frequency points of the signal from the ISN and compares the current signal strength with a reference value to determine whether the EMI test system works normally according to the comparison.

The invention relates to an upward and downward communication test device of a power consumption information collecting terminal. The upward and downward communication test device is mainly formed in a way that a wireless communication test device and a carrier communication test device are respectively connected with a computer system. The wireless communication test device is used for being connected with an upward communication interface of a power consumption information collecting terminal to be tested, and the carrier communication test device is used for being connected with a downward communication interface of the power consumption information collecting terminal to be tested. The wireless communication test device consists of an 8960 communication comprehensive test device, a 9010a signal analysis instrument and a radio frequency switch, and the carrier communication test device consists of two LISN (line impedance stabilization network) power supplies, a receiver, a gating switch, a wireless router, a serial port communication server, a 485 communication switch and a controlled attenuator. The device has the advantages that the detection on the communication capability and the index of a GPRS (general packet radio service) channel and a carrier channel of the power consumption information terminal to be tested is automatically controlled through the computer system, the real-time, accurate and reliable basis is provided for the operation of the power consumption information terminal, and the normal and safe operation of the power consumption information terminal is ensured.

The invention provides a control system for improving the line impedance stabilizing network low-frequency sampling precision, and the control method thereof. The system comprises a T network unit, a decoupling unit, a communication control unit, an attenuator unit, measuring equipment and measured equipment. The decoupling unit is connected with the T network unit, the communication control unit, the measuring equipment and the measured equipment respectively; and the attenuator unit and the measuring equipment are connected in the forward direction. An inner relay is controlled by the communication control unit to select different sampling and decoupling capacitors in the decoupling unit; and combined with the design of output attenuator unit, the invention provides a convenient and effective scheme for improving the line impedance stabilizing network low-frequency sampling precision in a carrier communication performance test.

The invention relates to a circuit parameter optimization method for a V-type line impedance stabilization network. With the method of the invention adopted, a line impedance stabilization network (LISN) which can keep impedance constant in whole working frequency bands can be designed optimally; with the LISN adopted, it can be ensured that conducted emission experiment results are not affected by the self-impedance variation of the line impedance stabilization network; and algorithm optimized circuit parameter components are adopted, so that the experiment results are not affected by the voltage division of a blocking capacitor in a circuit. The circuit parameter optimization method can play a role of guiding the design and development of a line impedance stabilization network which is better in performance and is more convenient to operate. With the method adopted, line impedance stabilization networks which can be suitable for different tested articles can be designed and developed according to use requirements.

The patent is a design method for optimizing a filter to suppress switching noise. The method includes the steps of supplying power to a switching power supply through a line impedance stabilization network, using a purely resistive load as a load end and adding the load to the maximum output load of the switching power supply and separating common mode and differential mode noise which are produced by a switch line via a differential mode and common mode noise separator and the line impedance stabilization network. Furthermore, the differential mode noise passes a differential mode filtering network carrier board, network effect of differential mode filtering is detected by the use of an oscilloscope, output and input voltage ratio of filter network noise of the differential mode are compare, insertion loss value of the differential mode filtering network is roughly estimated, standard limit requirements are met with a minimum of differential mode filtering devices, and filter optimization is achieved. Meanwhile, common mode noise passes a common mode filtering network carrier board, network effect of common mode filtering is detected by the use of the oscilloscope, output and input voltage ratio of filter network noise of the common mode are compare, insertion loss value of the common mode filtering network is roughly estimated, standard limit requirements are met with a minimum of common mode filtering devices, and filter optimization is achieved.

The invention discloses a system and a method for testing low-frequency radiation immunity of a power line based on crosstalk injection, belongs to the field of electromagnetic compatibility testing methods of electrical and electronic equipment, and aims to solve the problems that a radiation immunity testing method based on a darkroom irradiation method is complex, time-consuming and high in cost, and the radiation efficiency of a low-frequency-band antenna below 1GHz is low. According to the invention, the number of radio frequency interference sources required by a crosstalk injection method is reduced from two to one through a line impedance stabilization network, and the problem of complexity of dual-source cooperative regulation and control is avoided. The radiation immunity test system provided by the invention adopts a near-field crosstalk method, the coupling efficiency is high, expensive equipment such as a microwave anechoic chamber and a broadband radiation antenna is omitted, the time cost and the equipment cost required by the radiation immunity test are saved, and the radiation immunity test system has a better application prospect in the field of electromagnetic compatibility test methods of electrical and electronic equipment.

A line impedance stabilization network (LISN) includes a power port for connecting to a power supply, an equipment under test (EUT) connection port for connecting to an EUT, and a first inductor connected between the power port and the EUT connection port. The coil includes a first end, an opposite second end, a wire connected between the first end and the second end, and a first resistor. The wire includes a plurality of coils, and the first resistor is connected between two different coils of the wire.

The invention, which belongs to the technical field of the electromagnetic-compatibility conducted emission testing, discloses a method for determining an output impedance and a voltage division coefficient of a V type line impedance stabilization network (LISN). According to the method, for an LISN with known element parameters in a description, the output impedance and voltage division coefficient of the LISN can be obtained based on calculation and analysis; and a tested piece interference voltage value that is measured practically by a receiver during a testing process can be corrected. According to the invention, the method plays an important role in correcting a conducted emission testing result and has guiding significance in improving the conducted emission testing precision.

The invention discloses an over-limit problem source screening method for an EMC test for a massage chair complete machine system. The specific working method comprises the following steps of 1, arranging a power supply, a tested EUT, a line impedance stabilization network, an EMI receiver, a PLC processing module and an NAS storage module in a metal plate detection chamber, and grounding through copper wires; and 2, connecting the tested EUT in the massage chair with the line impedance stabilization network through the first circuit switching chip, and selecting the connected EUT. According to the method, a detection circuit can be automatically replaced, detected and switched, operation is simple, efficiency is high, when radiation is received, antennas for receiving different frequency bands can be switched, the receiving effect is ensured, and received radiation data can be conveniently and automatically stored and automatically backed up.

The invention provides an air conditioner EMC (electro magnetic compatibility) optimization circuit, an air conditioner controller and an air conditioner. The air conditioner EMC optimization circuit comprises a ground wire, a rectifier bridge, a low-impedance path, a PFC (power factor correction) circuit and an inverter circuit, wherein the PFC circuit and the inverter circuit are sequentially connected with the output end of the rectifier bridge. The PFC circuit and the inverter circuit are connected with the ground wire through a distributed capacitor, one end of the low-impedance path is connected with the output end of the rectifier bridge, and the other end of the low-impedance path is connected with the ground wire. According to the air conditioner EMC optimization circuit, the air conditioner controller and the air conditioner, on the premise that the basic architecture of an air conditioner variable-frequency controller circuit is not changed, the low-impedance path is additionally arranged in the controller circuit, the high-frequency common-mode interference noise transmitted from the PFC circuit and the inverter circuit is transmitted to the PFC circuit and the inverter circuit again through the output end of the low-impedance path and the output end of the rectifier bridge, the high-frequency common-mode interference noise can flow back to an interference source and cannot be transmitted to a power line from the ground wire, and therefore the common-mode noise interference transmitted by the controller circuit is reduced, the common-mode current flowing to an LISN (line impedance stabilization network) is reduced, and the EMC test margin is increased.

The invention provides a line impedance stabilization network for a medium-frequency power supply, which is used for testing the electromagnetic compatibility and belongs to the technical field of electronic testing and measuring. Meanwhile, the invention further provides a design method for the line impedance stabilization network. The line impedance stabilization network is characterized in that: the line impedance stabilization network comprises a bottom cover, a shell, an output-end wire connecting post, an input-end wire connecting post, a signal port, a grounding terminal and the line impedance stabilization network; the line impedance stabilization network is fixed in a shell body formed by the bottom cover and the shell, the input end and the output end of the line impedance stabilization network are electrically connected with the output-end wire connecting post and the input-end wire connecting post at the two sides of the shell body, and one side of the output-end wire connecting post of the shell body is fixedly connected with the signal port and the grounding terminal. The provided line impedance stabilization network for the medium-frequency power supply can be used in a commercial power grid (50Hz/60Hz and 115V/400Hz) for a long term.