296results about How to "Improve waveform" patented technology

This optical receiving device for discriminating and recovering a data signal, which results from converting an optical signal input through a dispersion equalizer into an electrical signal and amplifying it to a pre-determined amplitude, by using a clock and data recovery circuit for discriminating a data signal at the decision point controlled to achieve the optimum position controls the dispersion characteristics of a dispersion equalizer so that the error count in the recovered data signal by using a clock and data recovery circuit will be minimized by controlling the eye pattern of the data signal which has been amplified to a pre-determined amplitude.

The present invention relates to a photovoltaic three phase synchronization control method realizing maximum power tracking swiftly and stably, which belongs to the technical field photovoltaic power generating control. The method includes the steps as follows: judging the DeltaP / DeltaV value according to the power difference DeltaP between the current time k and the previous time and the voltage difference DeltaV; working out the Iref(k) when the photovoltaic array produces the maximum power; using the Iref(k) to adjust the uq* under the coordinates in vectorial synchronous rotation with the electric network voltage; acquiring six ways of space vectorial SVPWM impulse series according to the rotation angle degree Theta of the three phase electric network voltage, with the aim to control the inverter in order to ensure that the output current of the photovoltaic inverter has the same phase position as that of the mains voltage while ensuring the photovoltaic array is realizing the maximum power output tracking. The power factor is 1. The present invention also can adjust the Idref(k) according to local load requirements, therefore achieving adjustment to the power factor, with low synchronization current harmonic wave distortion factor.

A power conversion system for driving a load is provided. The power conversion system comprises a power transformer having at least one primary winding circuit and at least one secondary winding circuit, the primary winding circuit being electrically connectable to an AC power source. The system further comprises at least one power cell, each of the at least one power cell having a power cell input connected to a respective one of the at least one secondary winding circuit. Each power cell also has a single phase output connectable to the load. A power switching arrangement including at least one power switch is connected to the power cell input and a DC bus, and a switch controller is connected to the power switching arrangement and the power cell input. The power cell also has a PWM output stage having a plurality of PWM switches connected to the DC bus and the single phase output. A local modulation controller is connected to the PWM output stage. The switch controller is adapted for monitoring and controlling a DC bus voltage according to a predetermined control methodology in both a motoring mode in which power from the AC power source is supplied to the load by the at least one power cell and a regeneration mode in which power from the load is supplied to the AC power source by the at least one power cell. The power conversion system also comprises a master controller in communication with the switch controller and the local modulation controller of each of the at least one power cell. The master controller is connectable to the load to monitor power flow thereto.

Provided is a welding system and method for controlling a welding system with an improved pulsed waveform suitable for use with metal core welding wires. The waveform includes peak pulses (of voltage, current, power, energy or a combination thereof) that aid in transfer of molten metal from the wire to the weld pool. The pulse duration is sufficiently short to avoid damage to the metal core welding wire. The waveform enables welding of thin metals and reduces spatter.

A shift register invention includes a plurality of stages outputting a plurality of output signals, in sequence. Each of the stages includes a driving part and a discharging part. The driving part includes a driving transistor. The driving transistor has a control electrode, a first electrode, a second electrode and a channel layer. The control electrode receives one of a start signal or an output signal of a previous stage. The first electrode receives a clock signal. The second electrode outputs an output signal of a present stage. The channel layer has a different length from a channel layer of a driving transistor of the previous stage. The discharging part discharges the output signal of the present stage based on an output signal of a next stage, therefore improving the electrical characteristics of the shift register.

The invention relates to a data acquisition unit for on-line detection of transformer partial discharge and a detection method thereof. The data acquisition unit detects and acquires the transformer partial discharge signals and transmits the signals to a host computer for processing via a transformer partial discharge signal amplification module, a high speed data acquisition module and a remote communication module. In the invention, proper program control filtering and amplifying circuit are designed and manufactured, the precision of signals is high, the design and manufacturing of a high-speed and large-capacity multiple-channel synchronous data acquisition module circuit are finished, the requirement of detecting external multi-channel circuits can be met, and the adaptability is good; the invention is characterized by rapid sampling rate and large storage capacity, etc.; the whole acquisition system can be divided into a plurality of channels, the maximum sampling rate of each channel can reach 20MHz and the maximum storage depth can reach 512 K words; the data acquisition unit finishes digitization of partial discharge signals and upload the signals for processing, thus effectively reducing the distortion and aberration of the partial discharge signals during transmission, meanwhile, the data is transmitted by adopting the GPRS wireless communication technology, which reduces the cost and facilitates the construction and installation.

The present invention which belongs to the matrix converter control technology is a control method for a matrix converter. An input phase voltage is divided into a main range and a transition range in which new P, M, N conditions and PM, NP, MN transition conditions are defined, some null vector is selected and the condition combination sequence of bidirectional power switches are adjusted in each modulation period to realize the safe, reliable and rapid commutation and the stable operation of the matrix converter. The present invention also provides a device to realize the present method, including a trigger driving circuit, an over-current protecting circuit, a synchronous signal detecting circuit, a voltage range dividing unit, a switch state control unit and a commutation control unit. Based on the two-step commutation strategy of the voltage of the transition range and without an extra measuring device to precisely detect the relative size relation of the input phase voltage, the present invention solves the problem of a short circuit caused by an inaccurate measurement of the input phase voltage during range alteration, and the waveforms of the output voltage and the input current are not affected.

The invention discloses a bifunctional direct current ice melting apparatus based on a voltage source type current converter and an ice melting method thereof. The direct current ice melting apparatus is characterized in that: the apparatus is in a bifunctional working mode. More particularly, in an ice-melting mode, the apparatus is in a rectification working state and can provide enough direct currents to carry out ice melting on an icing line; and in a non-ice melting mode, a corresponded switch switching and controlling strategy is utilized, so that the apparatus is in an inversion working state and is used as a static synchronous compensator (STATCOM) for operation; and thus, system reactive compensation is realized. Compared with a current source type ice melting apparatus, the provided novel apparatus enables an ice melting power to be increased, reactive power consumption to be reduced and harmonic output to be optimized; besides, the main characteristic of the apparatus is as follows: a dual mode working performance is designed; that is, energy-saving economic objectives of three-phase uniform ice melting and ice melting current minimization can be achieved in minimum ice melting time under an ice melting mode.

The termination circuit for use in a transmission line to transmit a differential signal includes a first series circuit of a resistive element and an inductive element connected between one of two signal wires of the transmission line and a reference potential, and a second series circuit of a resistive element and an inductive element connected between the other of the signal wires and the reference potential. The inductive elements of the first and second series circuits are magnetically coupled such that they generate magnetic fields having such directions as to reinforce each other when a common-mode signal flows along the transmission line, and generate magnetic fields having such directions as to weaken each other when a differential-mode signal flows along the transmission line.

The invention provides a cascade type time-interval variable-order multi-level static converter, which can be modularized; a previous-stage four-way isolation DC-DC (Direct-Current-Direct-Current) converter (1) is connected to a subsequent-stage four-unit cascade inverter (2); a novel time-interval variable-order multi-level control circuit (3) is connected between the previous stage and the subsequent stage; the converter is characterized in that the previous stage is adopted with four ways of mutually independent, staggered and parallel double-tube forward direct-current converters; the subsequent stage is a cascade structure composed of four single-phase H bridges; a carrier phase-shifting frequency-doubling SPWM (Sinusoidal Pulse Width Modulation) technology is adopted; the time-interval variable-order multi-level control circuit is connected between the previous stage and the subsequent stage; the previous stage of the static converter is beneficial to reducing input current ripple and reducing the volume of a filter; the subsequent stage is low in voltage stress of a power switch device, high in circuit modularization degree and low in loss; and, by means of the time-interval variable-order multi-level control circuit, on the premise of not increasing the number of independent sources of the previous stage, the more level number of output can be realized, and the THD (Total Harmonic Distortion) of the harmonic wave is low.

A first constant-current source supplies a charging current to a second terminal of a first capacitor in which a first terminal is grounded. A first terminal of a second capacitor is grounded, and a first switch is provided between the second terminal of the first capacitor and a second terminal of the second capacitor. A second constant-current source supplies current to the second capacitor, and a second switch is provided on a current path of the second constant-current source. A third constant-current source draws out current from the first capacitor and the second capacitor. A switch controller turns on the first switch and turns off the second switch when an output voltage appearing in the second terminal of the first capacitor reaches a predetermined upper-limit voltage. The switch controller turns off the first switch and turns on the second switch when the output voltage drops to a predetermined lower-limit voltage.

The present invention is related to a method and system for wave power generation. When a floating body rises with the wave, a hydraulic cylinder is being pulled to drive a hydraulic motor; the hydraulic motor will in turn drive the generation of power. When a stroke action of the hydraulic cylinder is completed, signals will be transmitted to a drum to release the rope, at which time the hydraulic cylinder will be reset. When the reset is completed, the distance between the floating body and the anchor base increases, the hydraulic cylinder is pulled again, thus repeating the above process. When the floating body drops along with the wave, the hydraulic cylinder is reset at first and then the drum retracts the rope. This system can automatically reset the hydraulic cylinder and do work multiple times during the process of one rising wave.

The invention relates to the technical field of power electronics, and aims to provide a current zero-crossing detection and dead zone compensation method used for a frequency converter. The method comprises the following steps of: (1) performing OR operation on drive signals of Wx and reversed Wx of an upper bridge arm and a lower bridge arm; taking the drive signal on which the OR operation is performed as a clock signal of a D trigger; performing isolation and transform on an output voltage Ux of the frequency converter to obtain a high-low level Sx serving as an input signal of the D trigger; and acquiring an output signal Qx; (2) judging the polarity of an output current within a dead time according to the Qx; (3) judging whether the Qx is flipped in each switch period Ts; and (4) determining the state of the output current in the switch period according to the number of flips Nf of the Qx in each switch period Ts. In inverted power supplies such as the frequency converter and the like, by using the method, current distortion and torque pulsation caused by the inaccuracy of current polarity detection and the inaccuracy of the dead zone compensation in a reciprocating zero-crossing stage of a current can be greatly avoided, and the waveform of the output current can be improved greatly so that the waveform is closer to a sine wave. Therefore, output torque is greatly improved.

The invention provides an aeroengine load spectrum filtering method based on a rain-flow counting method. The aeroengine load spectrum filtering method comprises steps that (1), rain-flow filtering for original spectrum of aeroengine load spectrum is carried out to acquire rain-flow filtering spectrum; and (2), based on the rain-flow filtering spectrum, points of multiple original load spectrum are added, and the filtering spectrum based on the rain-flow method is lastly acquired. Through the method, the load loading / unloading path information can be reflected, namely, on the basis of deleting small circulation, circulation peak / valley values of the filtering spectrum and the original spectrum are guaranteed to be identical, and the path of the original spectrum is reserved to a maximum degree; singular points can be more effectively eliminated, threshold filtering for signals is carried out to eliminate noise of the signals, and signal processing efficiency is improved. The method is advantaged in that research on flight parameter pre-processing and outlier elimination in an aeroengine load spectrum compilation process is realized.

A tunable dispersion compensator and a tunable dispersion compensation method having an excellent dispersion compensation characteristic are provided. A tunable dispersion compensator 201 is constructed of first to fourth ring resonators 2021 to 2024 connected in series along a common linear waveguide 203. The linear waveguide 203 is provided with first to fifth mode filters 2041 to 2045 in such a way as to sandwich the ring resonators 2021 to 2024 respectively. These mode filters 2041 to 2045 eliminate high-order mode noise components which transmit through the linear waveguide 203. The mode filters 2041 to 2045 are constructed with the width of a central waveguide reduced or in a curved shape.

A space is set substantially in a tropical rain forest type environment to activate a human's essential brain region and realize an environment suitable for the human's brain by arranging a device for setting the tropical rain forest type environment based on characteristics of activating human's essential brain region responsive to tropical rain forest type environment information, in a space such as an urban space, a housing space or other living space. The tropical rain forest type environmental information has higher density and higher complexity than those of urban space type environmental information, and includes at least one of auditory information, visual information, and super perceptual information of aerial vibration. The tropical rain forest type environmental information is comfortable for the human with no excessive stress, and is environmental information for effecting prevention and treatment of diseases due to stress by realizing the environment comfortable for the human's brain.

The present invention is to provide an LD-driver that enables to adjust the waveform of the driving current to the LD even the driver is constituted with a current controlled device such as bipolar transistor. The LD-driver of the invention provides a plurality of modulation current sources each having a function to set the amplitude, the phase and the pulse width of the current output independently. The LD is provided with the modulation current superposed with each current derived from respective current sources.

A tunable dispersion compensator and a tunable dispersion compensation method having an excellent dispersion compensation characteristic are provided. A tunable dispersion compensator 201 is constructed of first to fourth ring resonators 2021 to 2024 connected in series along a common linear waveguide 203. The linear waveguide 203 is provided with first to fifth mode filters 2041 to 2045 in such a way as to sandwich the ring resonators 2021 to 2024 respectively. These mode filters 2041 to 2045 eliminate high-order mode noise components which transmit through the linear waveguide 203. The mode filters 2041 to 2045 are constructed with the width of a central waveguide reduced or in a curved shape.

In a multilayer interconnection layer of a mother board and a memory module, a position relationship between a bus interconnection layer and a conductive layer of a power supply layer or a ground layer opposite to the bus interconnection layer is substantially held in not only the mother board but also the memory module and a relationship of multilayer interconnections is unified. As a result, it is possible to reduce disturbance of a return current of a high frequency signal given to the bus interconnection layer, to prevent degradation of quality of a signal waveform caused by the disturbance of the return current, and to prevent unnecessary electromagnetic waves from radiating caused by the disturbance of the return current. When a position relationship between the bus interconnection layer and an opposite conductive layer is not held at a constant, a similar effect is obtained by disposing a bypass capacitor in the vicinity of a portion where a plane of the bus interconnection layer and the conductive layer is switched.

The invention discloses a MIMO radar waveform optimization method, used to improve parameter estimation performance of a MIMO radar system under a condition that target prior information exists in a clutter scene. Implement method thereof comprises: firstly, establishing a MIMO radar signal model, and deriving Cramer-Rao bound (CRB) of an unknown parameter based on the model; based on a Trace-Opt criterion, minimizing trace of the CRB, establishing a waveform optimization model; and based on a diagonal loading (DL) method, relaxing a nonlinear optimization problem to a semi-definite programming (SDP) problem, to obtain efficient solution of the optimization problem, so as to improve parameter estimation performance of the system. Compared with an uncorrelated transmitted waveform and a non-prior scene, the method can obviously improve system parameter estimation performance.

The invention relates to an active sonar target simulator signal processing method which comprises the following steps: an underwater acoustic energy transducer picks up audio information in water and converts the audio information into an electrical signal; an analog-to-digital converter converts the analog electrical signal into a discrete digital signal; the discrete digital signal is transmitted to a signal processing chip and is processed by an SPI serial port; a double-buffer area is arranged in a storage area in the signal processing chip, and read data are placed into the double-buffer area in a circular way; the digital signal in the double-buffer area is read according to a fixed time interval and converted into the analog electrical signal; and the underwater acoustic energy transducer is promoted to convert the signal into a voice signal by filtering ultraharmonics and amplifying by a power amplification circuit. The invention can simulate the acoustic reflection of a submarine and recognize signal forms of a single frequency signal and a frequency-modulated signal, signal time length and signal strength according to a received active sonar signal, transmit a signal in the same form after increasing a certain reflection strength and also increase the Doppler frequency shift for simulating the relative motion between the submarine and a sonar.

The invention discloses a radar pulse modulator for modulating direct-current high voltage into various time intervals and various frequencies. A signal receiving module is connected with a pulse generator through a serial interface circuit, the output of the pulse generator is respectively connected with a first driving circuit and a second driving circuit, the outputs of the first driving circuit and the second driving circuit are respectively connected to the primary coil end of a pulse transformer, the outputs of high-voltage power supplies of the first driving circuit and the second driving circuit are respectively connected with an MOSFET branch module and an IGBT branch module, and the MOSFET branch module and the IGBT branch module are in parallel connected and then connected with the input of a branch switching controller; and an FPGA chip of the pulse generator is respectively and externally connected with a parallel output interface, a parallel input interface, a program memory, a switching control switch and a trigger pulse switch. The radar pulse modulator can conveniently control the preheating time of a transmitter, the pulse widths and the repetition frequencies of trigger pulse, restrain the same frequency interference, and obtain better wave forms during a high voltage modulating process; in addition, the driving circuits have faster on-off speed and higher voltage and power capacity.

The pulse mode electron generator of the invention includes a field emission cathode with electron-emitting micropoints associated with a grid biased by means for positively biasing the grid and an anode attracting electrons emitted by the cathode. The grid is biased by a permanent positive pre-bias voltage generator delivering a rest voltage which is slightly lower than the emission threshold voltage of the cathode and in series with a positive pulse voltage generator delivering a pulse component of sufficient value to exceed the emission threshold voltage of the cathode. This facilitates the pulse mode production of electrons and reduces the power consumption needed to produce the electrons.

The invention discloses a high-power brushless double-fed motor three-level bidirectional frequency conversion speed regulation system, which is characterized in that the system is composed of a brushless double-fed motor and a three-level dual PWM AC speed regulation system. The dual-PWM AC speed regulation system includes a brushless doubly-fed motor three-level PWM rectifier unit and a brushless doubly-fed motor three-level inverter unit. In the main circuit structure of the three-level dual-PWM AC speed regulation system of the present invention, four power devices are connected in series for each phase bridge arm. The three-level PWM rectifier can realize two-way flow of energy, improve energy recovery rate, and reduce energy loss of motor AC speed control system. It is suitable for high-voltage and high-power motor drive occasions.

A semiconductor device of the invention is a semiconductor device that controls a transistor that controls an electric current that flows through a light emitting element, the transistor including a gate that is connected to one end of a capacitor. The semiconductor device includes: a first terminal that is connected to the gate of the transistor and the one end of the capacitor; a second terminal that is connected to the other end of the capacitor; a first driving circuit that outputs a first control signal to the first terminal; and a second driving circuit that, in order to control the transistor in an on-state or an off-state, activates or deactivates a second control signal, and outputs the second control signal to the second terminal, the second control signal having a potential lower than a potential of the first control signal.

The invention provides an any wave form complex signal generator which comprises a local bus control module, a FIFO speed adjusting module, a D / A digital-to-analog converting module, a low-path filtering module, an analog converter, wherein the local bus control module is connected with the storing module; the local bus control module is also connected with the PIC bus controller and the PIC bus of the computer by local bus and PIC bus pin; the analog converter arranges a signal output port and a carrier input port which is connected with the external signal source.

An apparatus that reduces sampling errors for data communicated between devices uses phase information acquired from a timing reference signal such as a strobe signal to align a data-sampling signal for sampling a data signal that was sent along with the timing reference signal. The data-sampling signal may be provided by adjustably delaying a clock signal according to the phase information acquired from the strobe signal. The data-sampling signal may also have an improved waveform compared to the timing reference signal, including a fifty percent duty cycle and sharp transitions. The phase information acquired from the timing reference signal may also be used for other purposes, such as aligning received data with a local clock domain, or transmitting data so that it arrives at a remote device in synchronism with a reference clock signal at the remote device.

The invention discloses a drag point identification processing method of a laser radar. The method comprises the following steps: acquiring waveform information of an echo corresponding to a detectionpulse; and based on the waveform information of the echo, judging whether the echo corresponds to the drag point. According to the invention, the intensity of the received echo signal is identified,if the echo amplitude is greater than the set expected value, the intensity of the next light emission is reduced, otherwise, the light emission intensity is increased. Meanwhile, a timing threshold can be determined according to the intensity of each echo signal. Through the detection and processing of the invention, the improved drag point waveform can be obtained, and more accurate measurementinformation can be obtained, such as distance information or reflectance information, etc.

The invention provides a halbach birotor self-sliding wide range speed regulation permanent magnet hub motor for an electric vehicle. The halbach birotor self-sliding wide range speed regulation permanent magnetism hub motor for an electric vehicle includes barrel-shaped inner and outer rotors, a rotatable stator with inner and outer double layer armature windings, two end caps with special structures, an automatic sliding structure fully utilizing mutual coordination of permanent magnet attractive force and a freewheel clutch, and a double reinforcing structure utilizing an electromagnetic clutch. Besides, the hub motor also utilizes a design of a wireless transmission position sensor signal, a sectional type speed regulation design, Halbach array permanent magnet setting, and a novel heat radiation design, and then becomes a unique motor after being integrated with the other patent: self-sliding motor intelligent cruise and PWM and SVPWM control conversion.

A positive and negative sequence decoupling control method for low-voltage ride-through compatible with a grid-connected photovoltaic inverter comprises the following steps: (1) a detected grid voltage is decomposed into a positive sequence component and a negative sequence component by a positive and negative sequence decoupling method, the output current of the inverter is also decomposed into a positive sequence component and a negative sequence component, and the components are controlled; and (2) the positive sequence component of the output current of the inverter is made to track the positive sequence component of the grid voltage, and the negative sequence component of the output current of the inverter is controlled to be zero so as to enable the inverter to correctly calculate the phase of the grid voltage in real time according to the drop of the grid voltage to realize phase control of the output current. The true phase of the grid voltage during low-voltage ride-through is detected by the positive and negative sequence decoupling method. Moreover, the positive sequence component and the negative sequence component of the current are controlled, and the power factor output by the inverter during low-voltage ride-through is precisely controlled. The same active current as normal operation can be output at low voltage, the output power remains unchanged, and the stability of the grid is maintained to the maximum.