6167 results about "Power frequency" patented technology

There is provided an inductive power line data coupler. The coupler includes (a) a magnetic core having a high magnetic permeability at a data communication frequency and being configured to allow a power line of a power distribution system to be routed through the magnetic core to serve as a primary winding, (b) a data signaling circuit that provides a secondary winding through the magnetic core for coupling a data signal between the power line and a communication device, and (c) a choke coil coupled to the data signaling circuit for creating a flux-canceling power frequency current opposite in direction and comparable in magnitude to a power frequency current. The coupler may also include a circuit for sensing a level of current in the power line.

A plasma reactor for processing a semiconductor wafer includes a side wall and an overhead ceiling defining a chamber, a workpiece support cathode within the chamber having a working surface facing the ceiling for supporting a semiconductor workpiece, process gas inlets for introducing a process gas into the chamber and an RF bias power generator having a bias power frequency. There is a bias power feed point at the working surface and an RF conductor is connected between the RF bias power generator and the bias power feed point at the working surface. A dielectric sleeve surrounds a portion of the RF conductor, the sleeve having an axial length along the RF conductor, a dielectric constant and an axial location along the RF conductor, the length, dielectric constant and location of the sleeve being such that the sleeve provides a reactance that enhances plasma ion density uniformity over the working surface. In accordance with a further aspect, the reactor can include an annular RF coupling ring having an inner diameter corresponding generally to a periphery of the workpiece, the RF coupling ring extending a sufficient portion of a distance between the working surface and the overhead electrode to enhance plasma ion density near a periphery of the workpiece.

An electronic identification tag, usually in very small size, responds to a reader with an identification code unique to the object to which the tag is attached. The stand-alone device responds to a reader signal by storing energy received from the signal, then using the stored energy to generate another signal that is encoded with identification information. In operation, a reader generates RF energy which can reach a multiplicity of such tags over a distance of several meters. The system minimizes power requirements for the tag by minimizing intelligence in the IC. Use of a transmit frequency which is different from the reader's power frequency reduces interference between the power pulse and information pulse, eliminates the need for filters and enables the multiplied clock reference frequency as the transmit carrier frequency.

Apparatus for supplying energy to a load, comprises a power supply unit (102) e.g. a switched mode electronic transformer or electronic ballast having an input for receiving current at mains frequency and a means for stepping-up said mains frequency to a higher frequency e.g. 30-50 kHz and an output for delivering energy at the higher frequency. A two part connector (108) has a first core portion (106) that has a primary winding (104) connected to the output of the power supply unit and a mating second core portion (112) that has a secondary winding (110) for delivery of energy to a load (114), the core portions being of a high resistivity material, e.g. a ferrite having a resistivity of at least 104 Ωcm. The apparatus may be used to power e.g. low voltage halogen or other incandescent lighting, fluorescent lighting, or an electric motor, a power supply for a computer, radio, television or like electronic device, a heater or the like.

An electronic identification tag, usually in very small size, responds to a reader with an identification code unique to the object to which the tag is attached. The stand-alone device responds to a reader signal by storing energy received from the signal, then using the stored energy to generate another signal that is encoded with identification information. In operation, a reader generates RF energy which can reach a multiplicity of such tags over a distance of several meters. The system minimizes power requirements for the tag by minimizing intelligence in the IC. Use of a transmit frequency which is different from the reader's power frequency reduces interference between the power pulse and information pulse, eliminates the need for filters and enables the multiplied clock reference frequency as the transmit carrier frequency.

The invention belongs to the technical field of energy conservation, and relates to a variable frequency energy-saving control method for a refrigeration system. The control method comprises the steps of: determining the mass flow of a refrigerant according to the change or change trend of cooling load, then determining consumed power of a compressor which satisfies the flow, predicting the minimum condensation pressure which ensures that the thermal load of a condenser satisfies the cooling load and the power change of the compressor through an established energy-saving control mathematical model, and gradually adjusting the power frequency of the compressor to ensure that the rotating speed of the compressor reaches a predicted value; and adjusting the opening degree of an expansion valve to ensure that the condensation pressure reaches to be lowest, realizing the minimum pressure difference operation between the condenser and an evaporator, and ensuring that the operation energy consumption of the refrigeration system is lowest. The method solves the optimizing control problem of the compressor, the expansion valve and a fan in the system, utilizes the energy-saving control mathematical model to perform joint regulation on controllable factors (such as the rotating speed of the compressor, the opening degree of the expansion valve, and the air volume of an outdoor unit) of the operation of the system, ensures that the refrigeration system operates at a best operating point, and realizes the further energy conservation of the refrigeration system based on the variable frequency regulation.

A variable frequency power system with a power source having a rotating output and a speed control to regulate rotational speed of the rotating output. A generator coupled to and driven by the rotating output of the power source, whereby the speed control of the power source directly controls output power frequency of the generator due to control of rotational frequency of the rotating output. A voltage regulator connected between the generator and the motor regulates output voltage from the generator to the electrical motor load. A system controller controls output power frequency of the generator. The system controller interfaces with the speed control of the power source and configured to monitor generator output and operational conditions of the electrical motor load. The system controller adjusts the speed control based on generator output and operational conditions of the electrical motor load.

The utility model relates to a digitized high voltage direct current power supply, and comprises a main power circuit, a digitized control circuit based on DSP and a control program of host computer based on PC, wherein the main power circuit comprises a three phase rectifying element [1], a soft start element [2], a filter element [3], a resonance inverting element [4], a high frequency and high voltage transformer [5], a doubling circuit [6] and a two-stage voltage divider [7]; the digitized control circuit based on DSP comprises an interface circuit of IPM drive signal, a high voltage feedback element, a resonance overcurrent protection element, a soft start circuit and a serial communication interface circuit. The voltage of power frequency electrical network is converted into DC voltage which is used as busbar voltage by three phase rectification, soft start and filter, and the busbar voltage is converted into 20KHz quasi-sine-wave by the resonance inverting element which is driven by a phase difference computed by the DSP according to feedback signal, and then 0-100Kv AC high voltage is output by the high frequency and high voltage transformer [5] and the doubling circuit [6]. The utility model adopts a host computer as a control device, and outputs the voltage via the control instructions of the DSP, therefore meets the requirements of voltage withstand test of insulation material.

The invention relates to a control method which can be applied to an active-clamp flyback miniature photovoltaic grid-connected inverter device. The active-clamp flyback miniature photovoltaic grid-connected inverter device comprises a flyback converter and a power frequency polarity conversion circuit. In the device, a current reference is used for controlling a flyback primary-side current peak value so that the device can output a half-wave sinusoidal current, and the output voltage is clamped by a grid voltage. When the instantaneous power is lower, a constant frequency current discontinuous mode in combined with a variable frequency current critical continuous mode is adopted in the flyback control method. When the flyback converter works in a variable frequency current critical discontinuous mode, an auxiliary switching tube can be conducted for a period of time when the secondary-side current of the flyback converter reaches zero, the conduction time can be accurately controlled by a digital chip, thus realizing the leakage inductance energy feedback and the soft switch of a master switching tube under the condition of wide-range output voltages and different instantaneous powers and greatly improving the efficiency under the condition of full loads.

There is provided an inductive power line data coupler. The coupler includes (a) a magnetic core having a high magnetic permeability at a data communication frequency and being configured to allow a power line of a power distribution system to be routed through the magnetic core to serve as a primary winding, (b) a data signaling circuit that provides a secondary winding through the magnetic core for coupling a data signal between the power line and a communication device, and (c) a choke coil coupled to the data signaling circuit for creating a flux-canceling power frequency current opposite in direction and comparable in magnitude to a power frequency current. The coupler may also include a circuit for sensing a level of current in the power line.

A gas distribution ceiling electrode for use as a capacitive source power applicator and gas distribution showerhead in a plasma reactor includes a metal base and a process-compatible protective layer on the interior surface of he electrode having a dopant impurity concentration within a range corresponding to a minimal change in RF power absorption in the protective layer at an RF source power frequency with changes in coating temperature and or thickness. The metal base may have a set of first arcuately slotted gas passages and a set of pressure-dropping orifices coinciding axially with the top ends of the gas passages. The protective coating a set of arcuately slotted gas passages in registration gas passages of the metal base. The pressure drop in the orifices and the electric field drop in the slotted gas passages are both sufficient to maintain the pressure and electric field within the gas passages within a range that prevents arcing.

A method and apparatus for adaptively maintaining the power-frequency spectrum in a reverberation chamber. The invention is thus capable of maintaining a relatively constant power-frequency spectrum in the chamber even when a device under examination is placed into the chamber which exhibits selective frequency absorption and or directional frequency absorption. The object disposed within the chamber need not necessarily be a device under examination. Rather, the present invention can also adaptively maintain a relatively constant power-frequency spectrum when heating any material disposed within a electromagnetic wave chamber.

The invention discloses an automatic identification method and system of low-voltage power distribution network topology based on based on power frequency carrier communication technology. A concentrator and an automatic topology identification device are installed beside each transformer in a low-voltage distribution network court, the concentrator and the automatic topology identification device are connected by a 485 line, a dual-mode collector is internally or externally arranged on an intelligent electric meter of the low-voltage distribution network court, an intelligent power distribution network topology identification master station is installed in a power marketing center or a power operation and inspection department, then the intelligent power distribution network topology identification master station performs automatic identification via the above equipment, the automatic identification converts the newly established topology link relation table data into a geographical topology diagram and a logic topology diagram of the low-voltage power distribution network, updates the original geographical topology diagram and the original logic topology diagram of the court, and records a topology state change event. The automatic identification method and system disclosed by the invention are conducive to updating the data in real time and greatly improving the timeliness of operation and maintenance, and patrol and repair, and play an important role of improving the economic benefits of power enterprises.

A load monitoring apparatus for monitoring the load applied to a portable generator. The apparatus includes a sensor, and a humanly perceptible indicator that indicates at least one discontinuous load power frequency.

The invention discloses a control circuit for a voltage dropping type power factor corrector, which is used for controlling a voltage dropping converter to realize the power factor correction function. Inductance current critical intermittent control of changed on-time is performed on a Buck circuit through the control circuit to ensure that the on-time of a switching tube rises in the power frequency period along with increase of input voltage; and the critical intermittent working mode of inductance current in the Buck circuit is controlled, and when the inductance current is greater than zero, the junction capacitance of the switching tube and inductance are resonated, and the switching tube is connected when the voltage resonance of the junction capacitance reaches the volley bottom. The control circuit for the voltage dropping type power factor corrector has the characteristics of ensuring high power factors in the whole input voltage range, and meeting the harmonic requirements of IEC 61000-3-2 Class C, Class D, along with high efficiency.

An acoustic detection of a discrete acoustic signal allows to detect a leak behind a casing (23) of a borehole. An acoustic amplitude (AA) is sampled during a recording time period (24;64) at a determined position along the tube. Time intervals (26;66) are defined inside of the recording time period (24), and for each time interval (26) the measured acoustic amplitudes are processed to obtain respectively a corresponding power-frequency spectrum (261). A plurality of the power-frequency spectra are analyzed to identify the discrete acoustic signal by detecting time and frequency dependant changes of power. Preferably the processing involves a Fourier transform analysis. A power-frequency time plot is used to conveniently identify the discrete acoustic event.

The invention discloses a controller and method for simulating the active power frequency of a double-fed induction generator (DFIG) in combination with inertia and over speed. The controller comprises a frequency deviation detecting module, a blocking module, a regulating variable setting module, a time delay module and a speed protecting module which are connected in sequence, wherein a real-time grid frequency signal and a frequency setting value are respectively input in the frequency deviation detecting module to obtain the frequency deviation signal of the grid at that time; the frequency deviation signal enters the regulating variable setting module through the blocking module, and the regulating variable setting module obtains a speed regulating variable according to the frequency deviation signal; and the speed protecting module enables the DFIG unit to exit frequency modulation under an abnormal speed condition, and can put into the frequency modulation again after time delay for a period of time. The controller has the beneficial effects that large-scale double-fed wind power integration takes the place of a conventional synchronous generator to cause that the system inertia is reduced and thus the transient stability of system frequency is worsened, and the comprehensive frequency controller provided by the invention can effectively solve the problem.

A system and method are described in which power is inductively supplied to a product or a package containing a product. This power is received via a coil and used by a light source to further enhance the presentation of the product or packaging. The illuminated light draws more attention to the product or package and thereby increases the probability that a prospective buyer till buy the product. Power is supplied to the package via a coil mounted to a shelf system. The frequency of the power supplied to the shelf coil may be changed to change the frequency at which the light source in the product or package illuminates.

The present invention discloses a ground fault detection system and method for an inverter. The ground fault detection method for the inverter includes a reference value setting step for setting a reference value for estimating a ground fault current and a reference value for deciding a ground fault, a ground fault current estimation step for comparing a current value obtained by adding up current values flowing through each phase of an output terminal of the inverter with the reference value for estimating the ground fault current, and estimating generation of the ground fault current when the calculated current value is larger than the reference value, and a ground fault phase decision step for deciding the phase in which the ground fault has been generated on the basis of a current difference value between start and end points of 0 vector sections of each phase or between start and end points of 7 vector sections of each phase. Therefore, even if the ground fault occurs in an output line during the load operation or a power frequency of the inverter is similar to an output frequency, the ground fault detection system and method for the inverter detect the ground fault to improve operational reliability of the inverter.

A method and apparatus for adaptively maintaining the power-frequency spectrum in a reverberation chamber. The invention is thus capable of maintaining a relatively constant power-frequency spectrum in the chamber even when a device under examination is placed into the chamber which exhibits selective frequency absorption and or directional frequency absorption. The object disposed within the chamber need not necessarily be a device under examination. Rather, the present invention can also adaptively maintain a relatively constant power-frequency spectrum when heating any material disposed within a electromagnetic wave chamber.

A power frequency distribution predicting unit predicts the power frequency distribution of a vehicle in a case where the vehicle travels a route with reference to the history of the vehicle power Pv when the vehicle traveled the route in the past. An operation condition setting unit sets the range of the required vehicle power Pv0 to operate the engine as an engine operation condition for controlling the energy balance between generated power and generated electric power of an electric rotating machine in a case where the vehicle travels the route to be at a preset value according to the power frequency distribution predicted by the power frequency distribution predicting unit. An operation control unit controls the operation of the engine according to the range of the required vehicle power Pv0 to operate the engine set by the operation condition setting unit.

An acoustic detection of a discrete acoustic signal allows to detect a leak behind a casing (23) of a borehole. An acoustic amplitude (AA) is sampled during a recording time period (24; 64) at a determined position along the tube. Time intervals (26; 66) are defined inside of the recording time period (24), and for each time interval (26) the measured acoustic amplitudes are processed to obtain respectively a corresponding power-frequency spectrum (261). A plurality of the power-frequency spectra are analyzed to identify the discrete acoustic signal by detecting time and frequency dependant changes of power. Preferably the processing involves a Fourier transform analysis. A power-frequency time plot is used to conveniently identify the discrete acoustic event.

The invention discloses a switching power supply for an AC / DC-DC self-adaptive instrument within an ultra-wide voltage input range. The switching power supply comprises an input protective circuit, an EMI filter circuit, a power frequency rectification and filter circuit, a high frequency rectification and filter circuit, a boosting conversion circuit, a flyback conversion circuit, a first voltage sampling circuit, a first current sampling circuit, a second voltage sampling circuit, a second current sampling circuit, a first PWM circuit, a second PWM circuit, an auxiliary power supply circuit, a power switching circuit, a voltage detection and comparison control circuit and an optocoupler isolation feedback circuit. A two-stage type cascade circuit is formed by the boosting conversion circuit and the flyback conversion circuit, and the automatic instrument can automatically adapt to power supply of an 85-265V alternating-current power supply and an 18-100V direct-current power supply.

A purpose of the present invention is disclosing a flyback type miniature photovoltaic grid connected inverter with a power decoupling circuit and a control method thereof. The inverter comprises a flyback converter and a power frequency polarity conversion circuit. The flyback converter is provided with a power decoupling circuit, a decoupling capacitance voltage grade is higher than output voltage of a solar energy photovoltaic array, decoupling capacitance voltage is allowed to fluctuate in a large range, thus decoupling capacitance capacity is decreased, power decoupling can be realized by only using a non-electrolytic capacitor, using an electrolytic capacitor is avoided, a service life of the miniature photovoltaic grid connected inverter is prolonged, and reliability is raised. Through the control method, not only is decoupling of miniature photovoltaic grid connected inverter output power and solar energy photovoltaic array output power realized, but also direct current voltage and current waveform outputted by the solar energy photovoltaic array can maintain smooth, a service life of the solar energy photovoltaic array is guaranteed, and realization of maximum power point tracking (MPPT) is facilitated.

The invention discloses a charging system for an unmanned aircraft. The charging system is characterized by comprising a power-taking device, an electric energy transmitting device, an electric energy receiving device and an aircraft-mounted battery, wherein an overhead transmission line is arranged on the power-taking device; the electric energy transmitting device is for converting power frequency alternating current into high-frequency alternating current; the electric energy receiving device is arranged on the unmanned aircraft; electric energy transmission is realized in a wireless manner between the electric energy receiving device and the electric energy transmitting device; the aircraft-mounted battery is arranged on the unmanned aircraft, is used for supplying power to the unmanned aircraft, and is connected in series to a current loop of the electric energy receiving device. Compared with the prior art, an electric unmanned aircraft charging system based on an alternating-current power transmission overhead line provided by the invention has the advantages that a full-autonomous and safe charging way is realized for the unmanned aircraft, and the distance per charge of the unmanned aircraft is prolonged. Meanwhile, a high-frequency inductive constant-current charging circuit based on an unstable alternating-current power supply is provided, so that unmanned charging operation is fully realized, the dependence of the unmanned aircraft on a ground base or a mobile base station is reduced, labor operation is reduced, and labor cost is reduced.

The invention discloses a new method for performing fault line selection by using the characteristic of a non-power frequency transient state fault component for extracting single-phase fault zero-sequence current by using Hilbert-Huang transform (HHT). The method comprises the following steps: performing EMD decomposition on fault zero-sequence current of each feeder line by using the HHT to acquire an IMF component of the zero-sequence current of each feeder line; constructing a resolving signal according to Hilbert transform, solving instantaneous amplitude and frequency of the zero-sequence current of each feeder line, and eliminating a power frequency component in the instantaneous frequency of the zero-sequence current of each feeder line to acquire a non-power frequency fault component; and forming a line selection criterion according to the characteristics that the amplitude of the non-power frequency fault component of the fault line is greater than that of the non-fault line and the polarity of the fault line is opposite to that of the non-fault line. The line selection method is not affected by an arc suppression coil, and is applicable to non-grounded, arc suppression coil grounded and high-resistor grounded systems, overhead lines or cable lines and cable overhead mixed lines; and the line selection result shows that the method applied to low-current single-phase grounding fault line selection is accurate and reliable.

The invention relates to a distributed single-phase earth fault ranging system that is used for realizing ranging of a fault on a high tension transmission line between two transformer substations. The system comprises: at least two sets of fault current detection device sets, which are installed at preset test points of a high tension transmission line; a remote wireless communication module; and a remote monitoring master station. The remote monitoring master station is respectively connected with the fault current detection device sets by the remote wireless communication module as well as receives fault currents collected by the fault current detection device sets by the remote wireless communication module; and the remote monitoring master station carries out comparison and an analysis according to positional data of the preset test points and length data of the high tension transmission line, so that a final fault position is obtained. In addition, a ranging method of the distributed single-phase earth fault ranging system is also provided. Power frequency fault current information and fault current travelling wave energy information are utilized to determine fault intervals; and different positioning equations are selected according to different fault intervals as well as fault point positions are determined; therefore, a dead zone problem can be solved, wherein the problem occurs when there are faults at a head and an end of a line, that is, when a fault point approaches a bus.

The invention relates to a method for testing the electricity of an ultrahigh-voltage transmission line based on electric field measurement, which comprises the following steps: 1, establishing a measurement point; 2, measuring an electric field; 3, establishing a transmission line power frequency inverse problem equivalent model; and 4, computing the voltage of the transmission line according to the electric field at the measurement point to obtain the actual voltage of each phase of transmission line, if the voltage of the transmission line is below 30 V, determining the transmission line is electrically neutral, otherwise, determining the transmission line is electrified. The invention also relates to a system for implementing the method for testing the electricity of the ultrahigh-voltage transmission line based on the electric field measurement, which consists of an electricity testing terminal and a data processing centre. The method and the system realize the non-contact electricity testing of the ultrahigh-voltage transmission line and ensure the safety of workers. Because the voltage level of the ultrahigh-voltage transmission line is high and a safe distance is long, the safe, effective and new method for testing the electricity of the ultrahigh-voltage transmission line is provided.

The invention discloses a micro-grid multi-inverter parallel voltage control method for droop control of robust power. The method comprises the following steps of: specific to each inverter in a micro-grid, computing and synthesizing an inverter output reference voltage by adopting a robust power droop controller; and introducing virtual complex impedance containing a resistance component and an inductive impedance component, and keeping inverter output impedance in a pure resistance state under a power frequency condition by adopting a multi-loop voltage control method based on virtual impedance and quasi-resonance PR (Proportional-Resonant) control, thereby realizing micro-grid multi-inverter parallel running and power equation, wherein the robustness of a micro-grid parallel system on numeric value computing errors, parameter drift, noise interference and the like is enhanced. Due to the adoption of the method, the defects of larger loop current of a parallel system, non-uniform power distribution and the like caused by the inductivity of the impedance output by inverters in the conventional droop method are overcome; and the method is suitable for multi-grid parallel uniform current control in a low-voltage micro-grid.