180 results about "Ac resistance" patented technology

Described herein are improved configurations for providing a stranded printed circuit board trace comprising, a plurality of conductor layers, a plurality of individual conductor traces on each of the said conductor layers, and a plurality of vias for connecting individual conductor traces on different said conductor layers, the vias located on the outside edges of the stranded trace. The individual conductor traces of each layer may be routed from vias on one side of the stranded printed circuit board trace to vias on the other side in a substantially diagonal direction with respect to the axis of the stranded printed circuit board trace. In embodiments, the stranded printed circuit board trace configuration may be applied to a wireless power transfer system.

A battery measuring device includes a temperature measuring unit which measures temperature T1 of a secondary battery, a resistance measuring unit which measures an AC resistance value and a DC pulse resistance value of a first discharging period of the secondary battery at the temperature T1, and an estimating unit in which an electric resistance Re1 and a reaction resistance Rc1 of the secondary battery at the temperature T1 are considered as,

• • Re1=AC resistance value
  • Rc1=DC pulse resistance value of the first discharging period−AC resistance value, and which estimates at least an internal resistance of the secondary battery using the temperature T1, electric resistance Re1 and reaction resistance Rc1.

A switching power supply unit is provided, in which core loss in a transformer or a level of heating due to AC resistance of the transformer can be reduced. A switching power supply unit has a transformer, an inverter circuit and a rectifier circuit. In a secondary side of the transformer, secondary wirings are connected to each other. In a primary side of the transformer, primary wirings are connected in series to each other, and connected to the inverter circuit to allow them to be driven in a time-divisional manner in phases opposite to each other in response to operation of the inverter circuit. The rectifier circuit has diodes connected to the secondary wirings to allow the secondary wirings to be driven in a time-divisional manner in phases opposite to each other in response to operation of the inverter circuit.

The invention discloses a method for inferring the internal DC resistance of a lithium ion battery. The method comprises the steps of performing cyclic tests on a sampled battery in the environment of a certain temperature and certain humidity, and testing the internal AC resistance IR0 and the internal DC resistance DCIR0 in a certain SOC state every certain cycles, establishing an IR-DCIR linear relation according to the internal AC resistance IR0 and the internal DC resistance DCIR0, when inferring the internal DC resistance of a battery in same model with the sampled battery, measuring the internal AC resistance IR of the battery to be tested at the same frequency according to the SOC state and the temperature and humidity conditions when the internal AC resistance of the sampled batter is measured, comparing the measured internal AC resistance IR with the established IR-DCIR linear relation, and performing ratiometric conversion on the internal AC resistance to obtain the internal DC resistance of the battery. The method for inferring the internal DC resistance of the lithium ion battery is capable of inferring the internal DC resistance according to the linear relation of the internal AC resistance and the internal DC resistance and avoiding the harm of multiple internal DC resistance tests by use of large current discharge to the battery, and also capable of obtaining higher detection speed and accuracy.

At least one graphene layer is formed to laterally surround a tube so that the basal plane of each graphene layer is tangential to the local surface of the tube on which the graphene layer is formed. An electrically conductive path is provided around the tube for providing high conductivity electrical path provided by the basal plane of each graphene layer. The high conductivity path can be employed for high frequency applications such as coupling coils for wireless power transmission to overcome skin depth effects and proximity effects prevalent in high frequency alternating current paths.

An apparatus (10) is set forth for measuring a return signal of a magnetostrictive sensor (20) that detects a force, torque, or pressure. The return signal includes noise, a DC resistance (44), an AC resistance and an inductance and the inductance is shifted ninety degrees from the AC resistance. The apparatus (10) includes a sensor filter (22) to remove the noise from the return signal. A sensor filter (22) shifts the return signal and more specifically, the inductance by an additional angle and the sum of the additional angle and the ninety degrees phase shift is defined as the final detection angle. To detect the inductance at the final detection angle, a wave filter (16) and a reference filter (28) shifts a reference signal by the final detection angle to trigger a first demodulator (26) to detect the inductance at the final detection angle. The inductance detected by the first demodulator (26) varies due to temperature. To remove the temperature from the measured inductance, the apparatus includes a DC detection circuit (42) to detect the DC resistance which is proportional to the temperature across the sensor (20). The DC resistance and the measure inductance are inserted into a correction equation to produce a corrected inductance which is independent of temperature. Instead of inductance, an AC resistance may be used in the equation.

The invention discloses a broadband Kelvin double electric bridge and a measurement method thereof, an automatic control system, a method and application thereof. A 1k Omega double-helical type resistance of difference of the alternate-current and direct-current is utilized to be a proportional element for the electric bridge, the electric bridge adopts the total arrangement of the electric bridge with the cross shape, therefore the comparing measurement of the electric bridge is utilized to calculate the resistance with the same nominal resistance in the wide range of direct-current to 100kHz. The electric bridge is utilized to calculate the resistance according to the difference of the double-helical alternate-current and direct-current between the electric bridge and five resistance measurement values of 1 Omega, 10 Omega, 100 Omega, 1k Omega, 10k Omega, the difference of the alternate-current and direct-current of Tinsley5685 type resistance on the five widely applied measurement values of 1 Omega, 10 Omega, 100 Omega, 1k Omega, 10k Omega are measured. The Tinsley5685 type resistance with the five measurement values can be utilized in the calibration of the resistance of the alternate current.

The invention discloses a steady state thermal circuit model-based method and device for determining a permissible current of an overhead conductor. The method comprises the steps of: firstly, loading a current to the overhead conductor, after the temperature of the conductor is stabilized, measuring the temperature of the conductor and an environment temperature of an environment where the conductor is in; according to the two temperatures, by adopting a special formula, sequentially calculating an AC resistance and an environment thermal resistance, and the maximum permissible current when the temperature of the conductor reaches 70 DEG C under the current outside environment; and comparing the current current and the maximum permissible current to carry out corresponding compatibility on the overhead conductor, and providing basis for load transfer, scheduling plan and the like, wherein the formula for calculating the environment thermal resistance and the maximum permissible current is based on a steady state thermal circuit model, the maximum permissible current can be obtained through measuring the temperature of the conductor and the environment temperature of the environment where the conductor is in and through simple calculation, and proved by experiments, result errors are in a permissible range.

Described herein are embodiments of a method and system for determining power loss in an inductor. In accordance with one aspect, a method is provided of determining power loss in an inductor. The method comprises modeling an inductor's windings and core using electromagnetic field simulation finite element analysis software executing on a computer. A ratio of AC resistance to DC resistance (Rac/Rdc) for the inductor is determined at one or more frequencies using the electromagnetic field simulation finite element analysis software. DC resistance (Rdc) of the windings is determined based on material properties and shape of the windings. The DC resistance is used to determine AC resistance (Rac) using the ratio, Rac/Rdc. Winding power loss at the one or more frequencies is determined based on the AC resistance (Rac). Core loss of the inductor is determined at the one or more frequencies using a core loss versus frequency curve. Winding power loss and core loss are summed at each of the one or more frequencies to determine total power loss at the respective frequency.

The present invention relates to a precise AC resistance measuring instrument and a measuring method thereof. The precise AC resistance measuring instrument comprises a microprocessor, a sine wave oscillator, a frequency divider, a phase controller, a first sine wave generator, a second sine wave generator, a filter, a signal selector, and a phase discriminator. The input end of the frequency divider is connected to the sine wave oscillator. The output end of the frequency divider is connected to the first sine wave generator and the second sine wave generator. The sine wave generated by the first sine wave generator is used as the test signal source of the phase discriminator. The sine wave generated by the second sine wave generator is used as the reference signal source of the phase discriminator. The vector synthesis voltage of a standard resistor and a tested piece is measured through the phase discriminator and is sent to the microprocessor, and the microprocessor calculates the resistance value of the tested piece. According to the precise AC resistance measuring instrument, the classical bridge measurement technology is substituted by the phase discriminator measurement technology, the difference between a common mode current output and a detector converter scale coefficient is eliminated, the measurement is more accurate, the structure is simple, and the cost is low.

An apparatus and a method reduce the ripple on a load current through an LED load. The load current is provided by a flyback converter, which is responsive to a feedback signal to maintain the output current at or near a selected magnitude. The LED load has an AC resistance which is at least one cause of the ripple on the load current. A stabilizing resistor in the current path to the LED load reduces the magnitude of the ripple caused by the AC resistance. The stabilizing resistor may have a constant stabilizing resistance value for different LED loads; or the stabilizing resistor have a dynamic stabilizing resistance value such that the stabilizing resistance value is greater when the LED load has fewer LEDs and is smaller when the LED load has more LEDs.

The invention relates to a method for testing the dielectric properties of liquid samples under high-pressure conditions for high-pressure physical property measurement. Before introducing liquid samples, use water as a calibration sample to calibrate the pressure of the device at room temperature, and put them into two holes of the Teflon gasket respectively. Ruby ball, pressure measurement by ruby ​​fluorescence method; place the anvil in the compaction device, turn the screw I slightly to seal the indium gasket between the contact surfaces of the upper anvil and the lower anvil, record the pressure in the anvil and the screw The relationship between the rotation angle of I; introduce the liquid sample, and rotate the screw I to apply pressure to the anvil; measure the dielectric constant of the sample by the parallel plate capacitor method: connect the current lead I and the current lead II to the dielectric constant measuring instrument respectively, Record the dielectric constant of the sample under various anvil pressure conditions; measure the AC resistance of the sample: sample I is connected to the lock-in amplifier I through the current lead III and the current lead IV, and the sample II is connected to the lock-in amplifier II through the current lead V and the current lead VI .

The invention discloses a cross-linked polyethylene insulated power cable with a divided conductor structure. Buffer water blocking tape, corrugated aluminum sheath and non-metallic outer sheath layer. The conductor is cabled by several fan-shaped strands to form a conductor with an overall circular cross-section. Insulation corrugations are used between each fan-shaped strand The paper is separated to insulate the strands from each other, so that the conductor is equivalent to being composed of several mutually insulated fan-shaped strands connected in parallel. Since the cross-sectional area of ​​a single strand is only a fraction of the total cross-sectional area of ​​the conductor, the "skin effect" and "proximity effect" of a single strand are greatly reduced, thereby achieving the purpose of reducing the AC resistance of the conductor.

The invention discloses an aerial cable which comprises a reinforced core and an aluminum stranded wire layer, wherein, the aluminum stranded wire layer is divided into an outer aluminum stranded wire layer and an inner aluminum stranded wire layer which are respectively formed by the twisting of a plurality of aluminum wires; each single aluminum wire is coated by an insulation layer; the aerial cable has the advantages that each single aluminum wire is coated or covered by the insulation layer; therefore, currents do not influence each other due to magnetic fields produced by adjacent wires during the transmission process of an alternating current (adjacency effect refers to the phenomenon that wires get close to each other, and the current density in each wire is not even any more) so as to eliminate AC resistance caused by the said 'crowded current' and cause the current transmission to be distributed on each wire, thereby greatly increasing the effective area of a cable conductor and reducing the impedance of the conductor and electric power consumption.

The invention discloses a transient state thermal circuit model-based method and device for determining a permissible current of an overhead conductor. The method comprises the steps of: firstly, loading a current to the overhead conductor, measuring the temperature of the conductor and an environment temperature of an environment where the conductor is in in real time; if wanting to know the maximum permissible current at some moment, calculating an AC resistance; by adopting a special formula, sequentially calculating the AC resistance and an environment thermal resistance of a moment to be detected, and the maximum permissible current when the temperature of the conductor reaches 70 DEG C under the outside environment of the moment to be detected; and comparing the current current and the maximum permissible current to carry out corresponding compatibility on the overhead conductor, and providing basis for load transfer, scheduling plan and the like, wherein the formula for calculating the environment thermal resistance and the maximum permissible current is based on a transient state thermal circuit model, the maximum permissible current can be obtained through measuring the temperature of the conductor and the environment temperature of the environment where the conductor is in and through simple calculation, and proved by experiments, result errors are in a permissible range.

The invention provides a digital alternating current resistance electrical bridge which comprises a two-stage induction voltage divider, a standard alternating current resistor, a tested alternating current resistor, a dual-channel synchronous sampling device and a power source, wherein both the standard alternating current resistor and the tested alternating current resistor are four-end resistors and comprise first voltage ends, second voltage ends, first current ends and second current ends; the dual-channel synchronous sampling device comprises a first channel and a second channel, and the second current end of the stand alternating current resistor and the second current end of the tested alternating current resistor are connected in series; the first current end of the standard alternating current resistor and the first current end of the tested alternating current resistor are connected with the power source through an isolation transformer. According to the digital alternating current resistance electrical bridge, an unbalanced electrical bridge structure is adopted, balance adjusting is not needed in the measuring process, and the problems that in a traditional measuring scheme, the balance adjusting process is tedious and the electrical bridge structure is complex are solved.

The invention relates to a device for detecting alternating-current resistance of a high-pressure cable split conductor. The device comprises a measuring meter, a center-through transformer, a sensor and a thermo-couple assembly, wherein the center-through transformer is connected with two ends of a conductor and is used for supplying current for the conductor, the sensor is connected with the center-through transformer, one input end of the measuring meter is connected with the center-through transformer by a signal wire, the other end of the measuring meter is connected with the sensor by a signal wire and is used for converting acquired voltage and current signals of the conductor into vector angles, and the thermo-couple assembly is arranged on the conductor and is used for measuring the temperature of the conductor. Compared with the prior art, the device has the advantages of being simple in structure, convenient to use, high in measurement accuracy and the like.

The invention provides a method and a system for measuring the pressure bonding resistance of a cable joint. The method comprises the steps: a first measurement point and a second measurement point are arranged on two ends of the cable joint, a third measurement point is arranged on the cable, the current is applied to the cable joint, the temperature of the cable joint is measured, when the temperature of the cable joint reaches a stable state, and the effective voltage, the effective current and the phase angle between the first measurement point and the third measurement point as well as between the second measurement point and the third measurement point are measured; according to the AC resistance calculating formula, the AC resistance between the first measurement point and the third measurement point is calculated, and the AC resistance between the second measurement point and the third measurement point is calculated, the absolute value of the difference value between the two AC resistance is calculated, and the pressure bonding resistance of the cable joint is acquired. The measuring process is simple, and the rigorous mathematical calculation is adopted, so that the pressure bonding resistance of the cable joint can be simply and accurately measured.

A high-frequency transmission line having low alternate current (AC) resistance is provided. One aspect of the present invention is a high-frequency transmission line disposed along a surface of an insulating support, wherein, letting F [Hz] be the frequency of an AC electric signal transmitted by the high-frequency transmission line and Ms [Wb/m] be the saturation magnetization per unit area, the frequency value F and the saturation magnification value per unit area Ms satisfy the following expression (1): Ms@(1.5×102)/F+5.7×10-8.(1)