1241 results about "Phase lead" patented technology

A motor control system for a brushless and sensorless DC motor for driving a compressor, pump or other application, includes a protection and fault detection circuit for detecting a locked rotor and a rotor which has stopped because of lost rotor phase lock. The motor control system also includes an off-the-shelf motor control integrated circuit having an input for disabling power outputs to the motor phase coils. The protection and fault detection circuit uses a back EMF sampling circuit coupled to the motor phase coils and momentarily disables power to the motor phase coils, via the motor control integrated circuit input, to determine if the motor rotor is rotating. The system also monitors supply voltage, supply current, temperature, and motor speed limits to detect faults and protect system components.

In a multiple power source system of the present invention that has an inverter connected to a reactance, such as three-phase coils in a motor, a high voltage battery is connected with a low voltage battery via one transistor (Tr2) and one diode (D2) included in the inverter and one phase coil (U-phase coil) of the three-phase motor. The transistor Tr2 is turned on to make the electric current flow from the low voltage battery to the U-phase coil. The transistor Tr2 is subsequently turned off at a preset timing, so that the electric energy accumulated in the reactance, that is, the U-phase coil, flows through the diode D1 into the high voltage battery and thereby charges the high voltage battery. This arrangement enables the charging process from the low voltage battery to the high voltage battery without any complicated circuit structure for the voltage step-up. The three-phase motor may be unipolar driven with transistors connected to one side of the inverter. The arrangement of the present invention does not require any complicated structure, which undesirably increases the size of the multiple power source system, in order to ensure mutual supplement of the electric energy between electric systems having a large difference in voltage, for example, an electric system for driving a hybrid vehicle and an electric system for its control circuit.

A device for converting alternating voltage to direct voltage and, conversely, direct voltage into alternating voltage. A series connection between the poles of a direct voltage side has at least four units each having a semiconductor element of turn-off type and a first diode connected in anti-parallel therewith. A first midpoint of the series connection is connected to an alternating voltage phase line and forms a phase output. Second midpoints of the series connection are connected to a midpoint of the direct voltage side through such units. An apparatus is adapted to control the semiconductor elements with a pulse width modulation frequency of at least one order of magnitude higher than the fundamental frequency of the alternating voltage of the phase line and the rest of the semiconductor elements with a frequency substantially lower and within or close to the frequency range of one or a couple of times of the fundamental frequency.

Floating electrically isolated active impedance modules are formed to attach to power transmission lines without breaking the lines such that the power line forms a secondary of the main transformer of the module. Each module includes an electrical energy storage device and a switching circuit, such as a single phase inverter, connected to the storage device and to the main transformer primary winding. The inverter can be controlled to couple a selected voltage to the transmission line through the main transformer primary winding which can provide effective positive impedance, negative impedance, or a voltage at or near phase quadrature with the line current. Many active impedance modules may be distributed over a power system grid to allow control of the impedance of the power lines in the grid and to steer power through the grid, with each module electrically isolated from ground and from other phase lines of the transmission system.

A timing recovery unit detects a phase offset and a frequency offset from a head area of reproduction data and initially corrects them. The timing recovery unit stores data in which a head reproduction signal has been made to be discrete by a fixed clock into a buffer. A phase offset detector detects the phase offset from the data head area in parallel with the operation for writing the data into the buffer. At the same time, a frequency offset detector detects the frequency offset from the data head area in parallel with the operation for writing the data into the buffer. A correction value of the detected phase offset and a correction value of the detected frequency offset are initially set into a digital PLL. While the data is read out from the buffer, a frequency lead-in and a phase lead-in are executed in the head area.

A timing recovery unit detects a phase offset and a frequency offset from a head area of reproduction data and initially corrects them. The timing recovery unit stores data in which a head reproduction signal has been made to be discrete by a fixed clock into a buffer. A phase offset detector detects the phase offset from the data head area in parallel with the operation for writing the data into the buffer. At the same time, a frequency offset detector detects the frequency offset from the data head area in parallel with the operation for writing the data into the buffer. A correction value of the detected phase offset and a correction value of the detected frequency offset are initially set into a digital PLL. While the data is read out from the buffer, a frequency lead-in and a phase lead-in are executed in the head area.

A method and system for enhancing communication signals in a power-line communications system, which uses high-voltage or medium-voltage power lines as a transmission medium. Because communication signals are subject to attenuation as they traverse the power-lines over a long distance, they are repeated and amplified by repeaters along the power-lines. The repeated signals are caused to interfere among themselves because of the delay and overlap of signals. By optically or wirelessly conveying communication signals between two phase-lines, and repeating signals in a phase-line hopping fashion, the distance between two adjacent repeaters on any one phase-line can be significantly extended in order to reduce interference.

A direct current brushless electric machine is described that comprises a sequence of permanent magnets where the N and S magnetic poles being alternately arranged adjacent to each other, each exerting a magnetic field; phase coils are composed of a group of conductors, each conductor being laid essentially in parallel with each other, each coil being displaced by a full range of a single magnetic pole of the permanent magnet, such that each phase coil is alternately disposed adjacent to each other; and magnetic field or every other coil is in the same orientation to form an armature positioned opposite to the permanent magnet movable with respect to the armature with a predetermined amount of air gap provided between the phase coils and the permanent magnets. The electric machine operates as a generator when the power is flowing from a prime mover, such as the turbine blade extracting energy from the wind or water. The electric machine operates as a motor when the current is applied to the coils in a sequence to move the rotor when the turbine blades move the wind or water.Also described is an aerodynamic system comprising inner and outer annulus disposed driving fans, with a pressure differential flow enhancing aerodynamic housing, able to concentrate and make laminar rough and turbulent intake air molecule flows, creating a smooth rotationally organized downstream vortex field, with maximum power extraction from building structure directed velocity flow enhancements.

The invention relates to a distribution network ground fault arc suppression method based on three-phase cascade H bridge converters. The three-phase cascade H bridge converters are adopted to replace arc suppression coils and mounted between phase lines and the ground, and power is supplied to capacitors on the direct current side of the converters by using phase voltages, so that boosting transformers and grounding transformers are saved, and the problem of source taking difficulty on the direct current side of the converters is solved. The converters inject current to a distribution network in a phase splitting mode to compensate the total current of a ground fault to be zero or to inhibit the phase voltage of the fault to be zero, so that the arc is automatically extinguished; and the reference compensation current is calculated by using real-time measured zero sequence voltage, so that the fault phase identification link is saved. The operation is simplified by using the voltage arc suppression method of controlling the zero sequence voltage to adjust the injected compensation current. In view of the influence of circuit parameters and load current on the arc suppression effect and the deduced relation between the ground fault residual current after the voltage arc suppression method is applied and the zero sequence voltage after the fault, an adaptive arc suppression method is put forward by using the zero sequence voltage as a voltage and current arc suppression method.

A multiple input, multiple output (MIMO) communications unit includes a multiplicity of analog front ends and a MIMO processor. Each analog front end is connectable to a different two of the wires in a subscriber premises and each handles data of one channel. The MIMO processor processes together the data of the channels. In one embodiment, the wires are the power line wires in a subscriber premises, including the phase, neutral and ground power line wires. In another embodiment, the wires are pairs of telephony wires.

A connection base is presented connecting current supply cables (1) of an electric motor to phase leads (2) of electric motor windings. The connection base comprises, a body (3) made of an insulating material and terminals (4) coupled thereto, the terminals being arranged to comprise at least one angle (α) and at least a first projection (41) and a second projection (42) on the opposite sides of the angle. The body is provided with first reception means (21) for receiving at least the first projection of the terminal and for keeping it in connection with the body. Furthermore the body is provided with second reception means (14, 15) for receiving a fastening means (12, 13) to be arranged at the first projection and for locking to the body. The fastening means being arranged to lock the terminal to the body and to fasten the phase lead to the terminal.

A steady state control method for a three-phase double-mode inverter. Off-grid steady state control is composed of outer loop power droop control, voltage feed-forward quasi-resonant control, and inner current loop dead-beat control. Therefore, the response speed of the inverter is raised, and the influence caused by the load fluctuation of a micro-grid is inhibited. Based on the off-grid steady state control, grid-connected steady state control introduces phase lead control to the power droop control. Therefore, the output voltage of the inverter is always slightly ahead of the power grid voltage, which avoids the energy pour backward phenomenon of the inverter due to a phase error, and realizes stable and reliable running in the grid-connected mode.

Disclosed a high speed magnetic levitation flywheel stability control system, comprises a displacement sensor, a displacement signal interface circuit, a rotary speed detect circuit, a magnetic bearing controller, and a magnetic bearing power amplifying drive circuit. Wherein, the magnetic bearing controller comprises a axial magnetic bearing controller and a radial magnetic bearing controller, while the radial one is formed by decentralized PID control module and a cross feedback control module whose outputs are connected by the feedback method in cross and parallel. Said invention utilizes the cross feedback control formed by forward whirling motion filter and backward whirling motion filter based on the decentralized PID control; it reaches the phase lead compensation to the forward and backward whirling motion by using the difference of their frequency and whirling motion directions, their variation rule of rotary speed, and the signal of rotary speed of flywheel. So the breakdown speed of flywheel is improved while the stable operation of magnetic levitation flywheel in whole rising and falling process is confirmed too.

The triphase AC sliding arc non-balancing plasma sewage treating apparatus includes one triphase AC high voltage power source, one water cooled glass reaction kettle, three knife metal electrodes connected separately to three phase line of the triphase AC plasma power source, one insulating cover, one atomizing nozzle and other parts. The sewage from the sewage source and the carrier gas from the carrier gas source are sprayed in the atomizing nozzle to form gas-liquid mixture entering to the water cooled glass reaction kettle, and the gas-liquid mixture drives the high voltage puncture arc to slide fast downstream and to form sliding pulse arc discharge in the surface of the electrodes, so as to generate non-balancing plasma including O, OH, H2O2, HO2., H, other active particles, ultraviolet ray, etc to degrade organic pollutants in sewage.

A motor drive control device and motor startup method prevent startup noise and reduce startup time. At startup, a current to which a rotor does not react is passed through two phase coils of a polyphase DC motor in succession, and a voltage polarity induced in a non-conducting phase is detected. A first operation decodes the detected signal, and determines phase coils of the motor through which a current should pass to rotate the rotor and the energization direction. A second operation forms a control signal for passing a current according to the determination to drive the motor, detects a voltage peak induced in the non-conducting phase during the drive, and performs switching control of a conducting phase. In normal operation, the position of the rotor is detected based on a back EMF in each phase, and rotation control is performed.

The invention relates to a VSC-converter for converting direct voltage into auxiliary voltage and vice versa, which comprises a series connection of at least two current valves (5, 6) arranged between two poles (7, 8), a positive and a negative, of a direct voltage side of the converter, each current valve comprising several series connected circuits (12), each of which circuits comprising a semiconductor component (13) of turn-off type and a rectifying component (14) connected in anti-parallel therewith, an alternating voltage phase line (16) being connected to a midpoint (15), denominated phase output, of the series connection of current valves (5, 6) between two of said current valves while dividing the series connection into two equal parts. Each of the series connected circuits (12) of the respective current valve comprises, in order to make possible a good voltage distribution between the semiconductor components (13) of turn-off type included in the respective current valve, a snubber capacitor (17) connected in parallel with the semiconductor component (13) of turn-off type included in the circuit. The converter (1) further comprises a resonance circuit (18) for recharging the snubber capacitors (17) of the current valves.

Active power converters and methods are presented for converting input electrical power to output electrical power with converter switching control in which the individual phase voltage command values are compensated according to phase line voltage imbalances to compensate the converter control to provide balanced phase currents in the presence of unbalanced phase supply line voltages.

A Hall sensing circuit generates a positional detection signal representative of a positional relationship between a rotor and a phase coil of a motor. A signal synthesizing circuit transforms the positional detection signal to a driving signal. Based on a comparison of the driving signal and a high-frequency reference signal, a pulse signal is generated for controlling a switching circuit to dive the motor. A current error signal is supplied through feedback to adjust a relative relationship between an amplitude of the drive signal and an amplitude of the high-frequency reference signal, thereby changing a duty ratio of the pulse signal. A duty-ratio limiting circuit is provided to limit the duty ratio of the pulse signal for ensuring a reliable rotation of the motor.

The invention discloses a method for inspecting a single-phase earth fault point of a power distribution network. The method includes the following steps: (1) injecting a test current signal and current detection: inspecting a signal source through a single-phase earth fault, respectively injecting the test current signal with the current value of A1 into three phase lines of the inspected power distribution network in sequence, and adopting a current detection device to synchronously conduct current detection and record detection results when the test current signal is injected into any phase line; (2) judging the existence of the single-phase earth fault: analyzing the detection results recorded in the step one; (3) determining fault sections: comparing the current on the left side and the current on the right side of a signal injecting point on the detected fault phase line, and determining the fault sections of the fault phase line according to the comparative results. The method is simple in step, easy and convenient to operate, low in input cost, low in workload, low in working difficulty, good in using effect and capable of solving a plurality of problems in an existing method for inspecting the single-phase earth fault point.

In a mobile robot, the actuator characteristics are dynamically or statically controlled, during motions of an entire robot body in the course of falldown or descent, to realize stable highly efficient motions. In each stage of the falldown motions, the characteristics of each joint site taking part in controlling the stable area are set so that the low range gain is low, the quantity of phase lead is large and the viscous resistance of the motor is large, in such a manner that these joint sites may be positioned to high accuracy in a controller manner to increase orientation stability. This assures the positioning accuracy of the joints as main component for controlling the quantity ΔS / Δt as a reference in controlling the falldown motions of the robot body to increase the motion stability.

A stator includes a stator core having slots, a stator coil comprised of three phase windings, phase busbars each electrically connecting a corresponding one of the phase windings to an inverter, and a neutral busbar star-connecting the phase windings to define a neutral point therebetween. In each of the slots of the stator core, there are arranged K in-slot portions of the phase windings of the stator coil in K layers so as to be radially aligned with each other, where K is an even number. The phase and neutral busbars are electrically connected with those in-slot portions of the phase windings of the stator coil which are arranged at the radially outermost layer or the radially innermost layer in the respective slots of the stator core so as to be circumferentially spaced from one another by M slot-pitches or more, where M is a slot multiplier number.

The invention relates to an input lack-phase detection circuit of a three-phase power supply, comprising a first current-limiting resistor, a second current-limiting resistor and a third current-limiting resistor which are respectively connected to a first phase line, a second phase line and a third phase line, the input lack-phase detection circuit also comprises a pull-up resistor, a third diode with a cathode which is connected to the third current-limiting resistor, a first optocoupler and a second optocoupler with output ends which are connected in series between the pull-up resistor and signal ground, a first diode which is connected with an input end of the first optocoupler in series between the first current-limiting resistor and an anode of the third diode, a second diode which is connected with the input end of the second optocoupler in series between the second current-limiting resistor and the anode of the third diode, a first capacitor which is connected with the input end of the first optocoupler in parallel and a second capacitor which is connected with the input end of the second optocoupler in parallel, and the pull-up resistor is connected to the output end of the lack-phase detection circuit. The input lack-phase detection circuit reduces the loss on the current-limiting resistors, so the current-limiting resistors are difficult to damage due to small heat, the reliability of the circuit is improved and the service life is prolonged.

Dual feed power supply system provides high reliability of a dual utility feed, with minimal interruptions in power supplied to critical loads during switching, and compensation for voltage sags occurring on the primary power feed. AC input buses are connected through a transfer switching apparatus to phase lines of a distribution bus. The transfer switching apparatus has a first input terminal connected to one of the phase lines of the first input bus and a second input terminal connected to one of the phase lines of the second input bus, and an output terminal connected to one of the phase lines of the distribution bus. Input switches allow switching from one or the other of the AC input buses to the distribution bus, with a fast transfer switch used to interrupt the supply of power from the input buses to the distribution bus during switching of the input switches.

The invention is suitable for the electric instrument field and provides a calibration method and system for electric energy meter, wherein, the method includes the following steps: a calibration control desk transmits basic calibration command frame to a calibrated electric energy meter to complete calibrating initialization of the meter; moreover, the basic calibration command frame carries the initialization parameters and the phase line value of the calibrated electric energy meter; when the initialization of the calibrated electric energy meter is completed, the calibration control desk which controls the output of a power source according to calibration steps reads the calibration parameters generated by a standard electric energy meter according to the output of the power source and transmits calibration command frame to the calibrated electric energy meter; moreover, the calibration command frame carries the calibration parameters and calibration step mark; finally, the calibrated electric energy meter completes calibrating operation according to the calibration parameters and the calibration step mark carried by the calibration command frame, the calibrated parameter calculation error compensation coefficient generated according to the output of the power source. The invention increases the reliability and the accuracy in electric energy meter calibration.

A power output apparatus includes first and second motor generators, first and second inverters and a relay circuit. The first and second motor generators include first and second 3-phase coils, respectively. The first inverter alters periodically the potential at a first neutral point of the 3-phase coil. The second inverter alters periodically the potential of the second neutral point of the second 3-phase coil at phase corresponding to a phase-inverted version of the potential change of the first neutral point. The relay circuit responds to a control signal from the control device to electrically connect first and second AC lines to a connector, and provides an alternating voltage generated across the first and second neutral points to the connector.