177 results about "Total impedance" patented technology

An ice detection system that detects the onset of ice accreation on an aircraft's external surfaces, continuously measures its thickness and growth time history and provides the type of ice, glaze or rime, is disclosed along with an independent way to confirm that the contaminant is known to be ice and only ice. Total impedance data, thermal conductivity value and complex dielectric properties are used to discriminate between ice, water, deicing fluid and snow with measurements made by low cost, low power consumption, low profile, miniature electronic chips, components and devices collocated together on the external surface in a thin pliant patch that does not effect the airflow about the aircraft. The ice detection system provides ice accreation data and warning signals to displays and aural signaling devices in the cockpit for the pilot and to the control console of a ground controller flying the aircraft if it is unmanned.

To provide an antenna element having a radiation electrode formed mainly on one surface of a dielectric substrate. The radiation electrode is substantially symmetric in form with respect to the center thereof, and has a first half and a second half with the same direction of main polarization of radiation emitted therefrom. Each of the halves of the radiation electrode may be a quarter-wave antenna for a wavelength of the emitted radiation. A power supply conductor to be connected to a high frequency signal source is connected to the first half of the radiation electrode, and a ground conductor to be connected to a ground is connected to the second half. A total impedance of the first half of the radiation electrode and the power supply conductor and a total impedance of the second half of the radiation electrode and the ground conductor can substantially match to one another, so that resonance between the halves of the radiation electrode can be enhanced and a wider bandwidth can be realized.

A radiofrequency thermal balloon catheter system which is accurate in the detection temperature, capable of miniaturization compared to conventional systems, reliably detecting pinholes and adhesion of thrombi. A thermocouple is composed of a radiofrequency transmission line and a single metal wire joined to the distal end thereof. A coiled electrode is formed in a coil shape by extending the distal end of the radiofrequency transmission line. The distal end of the metal wire is brought into pin-point connection with the proximal end of the coiled electrode. A radiofrequency generator monitors the radiofrequency output, total impedance, and reflection waves, while supplying the coiled electrode and a counter electrode plate with a radiofrequency of 1 to 5 MHz, and automatically controls the radiofrequency output, so that the temperature of the coiled electrode can be kept at a target value.

The invention discloses a multi-fan grid-connected resonance analysis method. The method comprises the following steps: on the basis of an output impedance model of an inverter, establishing a grid-connected equivalent model of a wind power plant; establishing a cable equivalent model according to the cable distribution characteristic under a harmonic state, and establishing the equivalent impedance of fan output power at a PCC (Point of Common Coupling) according to a relationship between the absorption power of the PCC and the fan output power to obtain the total impedance of a distributed wind power grid-connected system. The multi-fan grid-connected resonance analysis method has the advantages that the total impedance is calculated by establishing a distributed wind power grid-connected system model recorded with the cable and fan output power; the system model more accords with practical situations and has an application value and a practical significance for the resonance problem in an accurate analysis system.

The invention provides a quantitative analysis method for the subsynchronous oscillation stability of a wind turbine generator grid-connected system. The quantitative analysis method comprises the following steps: adding positive and negative sequence voltage disturbance signals to a wind turbine generator grid-connected point; establishing transfer functions of a wind turbine generator phase-locked loop, a current adjusting link and a PWM modulation link; obtaining positive and negative sequence impedance models Zp (s) and Zn (s) of a wind turbine generator, an equivalent impedance model Zg (s) of a power grid and a total impedance model Z (s) of a grid-connected system; determining proper fitting fractal polynomial orders m and n, and fitting the total impedance model Z (s) of the grid-connected system by using the fitting fractal polynomial orders m and n; solving a zero point of the fitting fractal polynomial in a fitting interval according to a fitting result, and determining theoscillation frequency and the damping level of the system according to the solved zero point. According to the invention, the method provided by the invention is provided based on the sequential impedance model in a static coordinate system. The method solves the problem that the traditional Nyquist stability criterion based on a sequential impedance model cannot quantitatively obtain the oscillation frequency and the damping level of the system in the prior art. The problem that the quantitative analysis method based on an aggregation RLC circuit model is narrow in application range is also solved.

A composite battery set, including a metal-ceramic ruthenium-oxide ultracapacitor and a secondary lithium-ion battery, is provided. The composite battery set is electrically connected to an electrical device, which cuts down the total impedance by the metal-ceramic ruthenium-oxide ultracapacitor to increase the output power and the current. The composite battery set is also able to react a pulse rise time less than 5 ms, to speed up the signal react time of the electronic device. And the composite battery set further includes a protective circuit module (PCM) to protect the secondary lithium-ion battery so as to extend the service life and lifespan.

The present invention relates to a method for locating single-phase ground fault of a low current grounding system power distribution network, including determining a total length L[total] and a total impedance Z[total] between two lines of M and N, and injecting signals when occurring a fault, when a P point between the M and N positions occurring a single-phase ground fault, systems of the two positions inject signals at the M and N position, and measures the amplitude of a return current signal as well as a phase difference between the return current signal and the injection voltage signal, after a line selection device has selected the fault phase; calculating a loop total impedance Z[M] grounded through the P point from the M and N ends, the modulo of the Z[N], and a phase angle Phi[M] of the Z[M] and the Z[N], according to |Z| = |U| / |I|, the measured injection voltage, the amplitude of the return current signal and the phase difference, a distance from the fault point P to the M position is further calculated through the following formula. By the method of the invention, it is easy to detect when the signal amplitude is strong, the attrition in the power distribution network is low, the algorithm is high, and the accuracy is high.

A first block (1) converts a DC voltage (Vi) into an AC voltage (V) of a high frequency, using a high-frequency oscillator circuit (4) and a step-up transformer (5). The first block (1) acts as a low-impedance power supply owing to suppression of leakage flux in the step-up transformer (5). A second block (2) and a third block (3) are connected to each CCFL (20). A ballast inductor (LB) causes the CCFL (20) to shine through the resonance with a matching capacitor (CM), and then maintains the stable lamp current during shining of the CCFL (20). The capacitance of the matching capacitor (CM) is separately adjusted for each CCFL (20), and thereby, the total impedance of the matching capacitor (CM) and the surrounding stray capacitances is matched to the impedance of the series connection of the ballast inductor (LB) and an overcurrent protection capacitor (CP).

A method and structure for a driver circuit having a plurality of parallel resistors, where a total impedance of all the resistors equals an impedance of an associated transmission line and a switch adapted to combine the resistors to control an output level of the driver. The driver circuit's switch selectively connects the resistors to either a voltage high signal or a voltage low signal. The first set of the switches connect a voltage high signal to a first resistor of the resistors and a second set of switches connect a voltage low signal to a second resistor of the resistors. The switch has a matched pair of opposite type transistors. The driver circuit has balancing resistors connected to the switch, the balancing resistors are sized to balance the resistance within the driver circuit. The resistors are the balancing resistors and the drivers are connected to the switches.

The invention discloses a non-contact type fluid electric impedance measurement device and method based on a digital phase sensitive demodulation virtual inductance technology. The non-contact type fluid electric impedance measurement device comprises an insulating measurement pipeline, an excitation electrode, a detection electrode, a metal shielding cover, a virtual inductance module, a signal processing and communication module and a microcomputer. An alternating current excitation signal with specific frequency, which is generated by the signal processing and communication module, passes through the excitation electrode; under a series resonance state, inductive reactance generated by the virtual inductance module is used for eliminating influences which are caused by the fact that the electrode and fluid pass through an insulating pipeline to form capacitive reactance of a coupling capacitor, so that the total impedance of a detection circuit is equal to equivalent impedance of the fluid in the pipeline; then a detection signal is subjected to digital phase sensitive demodulation; and real part information and virtual part information of electric impedance of the fluid are acquired. The invention provides a feasible way for solving an electric impedance measurement problem of the fluid in the pipeline. The non-contact type fluid electric impedance measurement device and method have the advantages of simple structure of a sensor, non-invasion, adjustable inductance value, no influences on the flowing of the fluid in the pipeline and the like.

The present invention provides a heating unit capable of easily and inexpensively adjusting total impedance based on tire mold size so that a power source can be used at a high power factor, and a tire heating apparatus using the same. A ferromagnetic metallic member 10a heats a tire mold M1 by heat conduction. An induction heating coil C1 is disposed on the side of the ferromagnetic metallic member 10a opposite the tire mold M1 to induction-heat the ferromagnetic metallic member 10a by generating magnetic field lines. A nonmagnetic conductor 30a is disposed on the side of the induction heating coil C1 opposite the ferromagnetic metallic member 10a to shield the magnetic field lines generated by the induction heating coil C1. A heating unit 100a including these elements heats the tire mold M1 storing a tire. A relative positional relationship among the nonmagnetic conductor 30a, the induction heating coil C1 and the ferromagnetic metallic member 10a is set by first spacers 71a and 72a and second spacers 21a to 23a.

The invention discloses a radio frequency device which is used for a plasma treatment device and comprises a radio-frequency power supply, a radio-frequency matcher and at least two groups of inductive coupling coils, wherein the proportion of the radio-frequency current in the inductive coupling coils is regulated by a current regulating device; and the current regulating device comprises a variable capacitor and an inductance component. The imaginary part of the total impedance including the current regulating device and the inductive coupling coils is inductive by reasonably setting the inductance value of the inductance component; and the impedance matching is realized by the traditional radio-frequency matcher comprising a plurality of capacitive components when the imaginary part of the total impedance is inductive, the matching process is simple and practicable, and the cost is also lower.

The invention provides a position detection device and method thereof. A position detection device comprises a plurality of intersecting regions which consist of a plurality of conductive strips to form a plurality of intersecting regions, wherein a depressed intersecting region is formed when depressed conductive strips electrically contact with each other. The contact position and the total impedance can be determined based on the depressed intersecting region, wherein the total impedance is the shunt impedance of all the depressed intersecting regions.

According to at least one aspect of the present disclosure, a method includes applying an alternating current having a frequency at a selected voltage to a sensor, wherein the voltage is applied between a reference electrode and a working electrode of the sensor, varying the frequency of the alternating current between a lower frequency and an upper frequency, measuring an impedance of the sensor between the reference electrode and the working electrode as a function of the frequency of the alternating current, analyzing the measured impedance to determine a total impedance of the sensor and the real and imaginary components of the total impedance at each applied frequency of the alternating current, and characterizing the sensor based on the total impedance at the low frequency end of the sensor and on the real and imaginary components of the total impedances.

Spiral coils generate very powerful electromagnetic fields by operating with two different but simultaneous resonant behaviors. Quarter-wave resonance is established by adjusting the frequency (and wavelength) of a radiofrequency (RF) voltage source until the length of the spiral conductor is equal to ¼ of the wavelength of the alternating voltage. This generates an electromagnetic standing wave with at least one peak node and at least one null node. Inductive-capacitive (L/C) resonance is established by optimizing the thickness and width of the wire ribbon used to make the spiral coil. When inductance and capacitance are balanced, the current response will synchronize with the voltage input, creating in-phase behavior, minimal total impedance, and maximal power output. If two such coils are placed near each other, they will create an extremely powerful electromagnetic field between them, which can promote chemical and plasma reactions involving charged particles such as ions or plasma particles, possibly including nuclear fusion reactions.