37 results about "Power line interference" patented technology

A circuit and corresponding method for controlling inrush current in an AC-DC power converter by providing a relay and a control circuit for limiting inrush current efficiently during cold startup, warm startup, and power line disturbance conditions. The relay is preferably connected in series with a bulk capacitor of the converter and in parallel with a limiting resistor and switch for shunting the resistor and switch so as to improve efficiency during operating conditions, at reduced size and cost. A preferred embodiment includes use of the circuit for AC-DC converters having active power factor correction.

Apparatus and methods for selective protection of an electrical load from disturbances on an input power line. A power protection circuit includes a selectively variable inrush current limiting circuit and a switch for disconnecting the input power line from the load. A control circuit determines that the electrical load is in a first operational state, such as a standby mode or normal operation, or a second operational state, such as full operation at rated current. The power protection circuit provides variable inrush current limiting to the electrical load in response to a first category of disturbances when the electrical load is in the first operational state. The power protection circuit inhibits disconnecting the electrical load in response to a second category of disturbances when the electrical load is in the second operational state. Species of selectively variable current limiting circuits are also described.

The invention relates to a micro-current signal extraction system. A signal is sampled by adopting a high-precision resistor, a current signal is transformed into a voltage signal; the voltage signal is transmitted to an analog signal preconditioning circuit, and sequentially passes through a primary amplification circuit, an analog filter circuit and a secondary amplification circuit to complete analog signal preconditioning; the signal which is subjected to analog signal preconditioning is output to a digital signal preconditioning circuit, and sequentially passes through an A/D (analog to digital) conversion circuit and a range switching and digital filter circuit; and a required micro-current signal is output after the digital signal conditioning is completed. According to the micro-current signal extraction system, the analog signal and digital signal conditionings are combined, a chopper-stabilizer integrated operational amplifier with high gain, high input impedance and high common mode rejection ratio is selected for preposed amplification of the system, 50Hz power line interference is inhibited by a dual-integral AD analog-to-digital conversion chip, and the I/O (input/output) interfaces can be greatly saved by virtue of 4-line serial communication, and high-efficiency and reliable data transmission can be realized. The micro-current signal extraction system can realize accurate measurement on micro-current, and can be used for insulation monitoring of electrical equipment.

The invention provides a method and a device for determining a topological relationship of power lines. The method comprises steps of sending measurement control information to radio nodes or receiving measurement data from the radio nodes, the radio points corresponding to the first and second positions of the power distribution network respectively; using a transmitting coupler set at the firstposition of the power distribution network to inject a topological relationship measurement signal into a power line, and using a receiving coupler located at the second location of the power distribution network to extract the topological relationship measurement signal from the power line; and using at least one of the measurement data of the topology relationship measurement signal and the power line interference measurement data reported by the radio points to determine the power line topology relationship. The method and the device can timely detect the change of the terminal load connection relationship of the power grid, improve the accuracy of the line load statistics and the line loss statistics, and have practicality.

The invention discloses a device obtaining direct current signals from alternative current and direct current overlapped signals. The device obtaining the direct current signals from the alternative current and direct current overlapped signals comprises a controller which sends out control commands according to time sequence, a whole cycle sampling switch connected with the controller and being switched on and off according to the control commands outputted by the controller, an integral circuit connected with an output end of the whole cycle sampling switch, a sampling maintain switch, a sampling holder connected with the other end of the sampling maintain switch, wherein an integral capacitance on the integral circuit conducts integral sampling of inputted overlapped signals, and one end of the sampling maintain switch is connected with the output end of the integral circuit. After sampling of the integral circuit is finished, under the control of the controller, the whole cycle sampling switch is disconnected, the sampling maintain switch is closed, voltage of the integral capacitance is transferred to the sampling holder to be kept. The device obtaining the direct current signals from the alternative current and the direct current overlapped signals can eliminate power line interference of the overlapped signals, ensure test of the instrument not to be influenced by alternative current signals, and improve test speed.

Power line disturbance hold up times are dynamically adjusted prior to the commencement of the power disturbance failover based on battery capacity of batteries in racks of the storage system as the batteries either fail, are repaired, or are added to the storage system having at least one uninterruptible power supply (UPS).

The invention discloses an electric power line interference signal extraction and synchronous playback device. The device is composed of a signal collection module, a signal playback module, a signal processing module, a signal storage module, a mode control module, a network communication module, a clock generation module and a control output module. Tested signals are collected by the signal collection module and are transmitted to the signal processing module for processing. The signal processing module stores the processed signals in the signal storage module and transmits the processed signals to the signal playback module. Triggering signals are input through the mode control module, so that the signal playback module is controlled by generated clock signals to output playback signals. The mode control module is connected with a network port through the network communication module. The mode control module is also connected with the control output module. The control output module is used for controlling output of state indication signals. Isolated sampling and high fidelity playback for non-working frequency signals on an electric power line are realized. The device can be applied to detection of a carrier communication function and an anti-interference capability test of a communication metering function of a meter.

The invention relates to a detachable flexible fabric electrocardio active dry electrode capable of inhibiting motion artifacts. The electrode is composed of a bonding layer, an active layer, an insulated package layer, a contact surface layer and an insulated shielding layer; hook and loop of a hook-and-loop fastener refer to the bonding layer as the first layer, a single-side flexible printed circuit board is the active layer as the second layer, insulating foam refers to the insulated package layer as the third layer, conductive cloth refers to the contact surface layer as the fourth layer,and an insulated fabric with the hollow center refers to the insulated shielding layer as the fifth layer. The detachable flexible fabric electrocardio active dry electrode capable of inhibiting motion artifacts overcomes skin stimulation and damage caused by a traditional wet electrode, can be repeatedly used and fixedly disassembled, and can be used in daily wearable devices. A first-level buffering amplification circuit with the specific active layer structure is adopted, the input impedance is effectively increased, skin-electrode impedance matching can be well performed, power-line interference and power line interference are reduced, the motion artifacts are reduced, and more accurate electrocardio signals are collected.

The invention specially relates to an analysis method of brain electricity of a forehead area. By means of testing and sampling, a reference brain electricity signal of the forehead is obtained, and an ocular electricity noise average waveform is extracted from the reference brain electricity signal. Band-pass filtering waves and notching filtering waves are adopted for removing high-frequency noise and power-line interference noise during real-time processing of brain electricity data to obtain a real-time primarily-filtered brain electricity signal of the forehead. According to a preset amplitude threshold value of the ocular electricity noise, blink cycle of the real-time primarily-filtered brain electricity signal of the forehead is extracted, and a method for overlapping the ocular electricity noise average waveform is adopted for counteracting the noise interference caused by blink in the real-time primarily-filtered brain electricity signal of the forehead. According to the analysis method of the brain electricity of the forehead area, purification and noise removal can be conducted on brain electricity data of a single electrode without arrangement of ocular electricity collecting electrodes, the signal-to-noise ratio of the brain electricity signal can be increased, and meanwhile, since a method for extracting a standard ocular electricity waveform in advance is adopted, the time for processing data in the later period is shortened, and the requirement for instantaneity is better met.

The invention relates to a coupling analysis method of multi-channel electroencephalogram based on multi-scale multi-variate transfer entropy and belongs to the technical field of non-linear dynamic causal systems and cerebral sensory motion network researches. The method comprises the following steps: 1, collecting a multi-channel electroencephalogram signal by adopting 32-channel Neuracle equipment; 2, respectively performing processing of removing baseline drift, electromyogram interference, eye movement interference and 50Hz power line interference on the collected electroencephalogram signal by adopting matlab software; 3, performing 20 different resolution decompositions on the multi-channel electroencephalogram signal by adopting a coarse-grained analysis method; and 4, analyzing the electroencephalogram signal under different resolutions among different time frequencies by adopting a multi-variate transfer entropy method, and quantitatively characterizing nonlinear coupling andinformation transfer characteristics among different cerebral sections. The coupling analysis method has the effects of describing the nonlinear characteristics among cerebral motion sensory cortex and deeply exploring the coupling intensity and information transfer among different regions of a brain.

The invention discloses a detection and processing circuit for a biological weak signal. The detection and processing circuit comprises a program-controlled filter circuit, a differential amplification circuit and low pass filters (LPF); the program-controlled filter circuit is formed by an operational amplifier AMP_1 and the low pass filters which are respectively formed by connecting a resistor with a capacitor in parallel; the program-controlled filter circuit is used for performing range-by-range detection and filtering on weak current; the differential amplification circuit is connected with the program-controlled filter circuit, and can be used for completing differential amplification of a converted small voltage signal and removing differential common-mode voltage so as to achieve the tail-to-rail function of output voltage; the low pass filters LPF are connected with the differential amplification circuit so as to filter off power line interference and high-frequency noise. According to the detection and processing circuit for the biological weak signal, disclosed by the invention, weak signal current different in magnitude is detected grade by grade by adopting program-controlled filtering so as to increase signal to noise ratio; meanwhile, a common-mode signal is filtered off by adopting differential amplification, and then, filtering is performed so as to increase the amplitude of the weak signal; the detection effect is good.

The present invention discloses a method for the removal of power line interference (PLI) to the signal parts of which are abrupt. First, to the non-abrupt part of the original input signal, we pass it to the notch filter, and get the output as the system output. Then, to the abrupt part, we subtract previous output from the original input signal; and add a straight line, connecting the starting and end of previous output, to the result of the subtraction to get the input of the notch filter. After processing of the notch filter, we add previous output to current output of the notch filter; and subtract the straight line as before from the sum to get the output of this step. We repeat this processing several times. During the detection of electrocardiogram (ECG), 50/60 Hz power line interference conceals the subtle changes in the original ECG, which affects the diagnosis. When the linear time-invariant (LTI) notch filter is used to the suppression of PLI, it usually causes ringing after the QRS complex, which affects the measurement of the Ventricular Late Potential and so on. The present invention uses the starting and end points of the QRS complex to process the input and output signal of the notch filter, so it is able to suppress PLI as well as to avoid the generation of the ringing.