128results about How to "Reduce harmonic interference" patented technology

An AC to DC converter with harmonic suppression is provided. The harmonic suppression is provided by forcing an instantaneous current conflict between series connected rectifier bridges 54, 80, such that a voltage waveform at 6 times the AC supply frequency of the AC supply is automatically generated. This waveform is then injected via a injection circuit to give harmonic cancellation.

The invention relates to a brushless doubly-fed motor excitation control system, which is characterized by comprising a PWM (Pulse-Width Modulation) rectifying unit, a first current sensor, a smoothing reactor, a contactor, an excitation controller and an inverter unit, an operation and display unit, an energy storage device, a BOOST reactor, a soft start circuit, a first voltage detection circuit and a second voltage detection circuit. The brushless doubly-fed motor excitation control system can always keep a speed-variable load-variable constant-frequency and constant-voltage power generation state when a brushless doubly-fed motor is at an electric operating state, the rotating speed of a brushless rotor rapidly changes and the load condition is within a larger range; and when the brushless doubly-fed motor is at the electric operating state, the brushless doubly-fed motor excitation control system can finish rapid adjustment of the rotating speed of the brushless rotor by excitation control and realizes multiple electric operating modes, such as synchronous operating, asynchronous operating and doubly-fed speed adjustment. When the load condition changes in a larger range, the brushless doubly-fed motor excitation control system can always keep the hard mechanical property of a synchronous motor. The invention also comprises the control method using the brushless doubly-fed motor excitation control system.

The invention discloses a bearing fault identification method based on LMD (Local Mean Decomposition) and wavelet de-noising. First, a fault vibration signal of a rolling bearing is decomposed through LMD to get a plurality of natural vibration composition PF components, and suitable PF components are selected according to the principle of maximum kurtosis and a cross correlation coefficient. Then, the selected PF components are de-noised through wavelet de-noising, and high frequency bands are superposed and reconstructed. Finally, experimental results on an MFS (Machine Fault Simulator) show that the method has obvious advantages compared with the traditional bearing fault diagnosis method.

The present disclosure relates to interference coordination methods and apparatuses, base stations, user equipments, and computer readable storage media. The method for interference coordination includes: determining whether there is intra-device interference between uplink and downlink transmission in two frequency bands by a user equipment UE; if the UE has intra-equipment interference between uplink and downlink transmission in two frequency bands, sending configuration information to the UE to configure Information is used to instruct the UE to stop sending uplink transmission of at least one frequency band in two frequency bands or to power back uplink transmission of at least one frequency band in two frequency bands during a time interval in which the base station sends control data for downlink transmission in each frequency band Retreat The embodiments of the present disclosure can achieve the purpose of reducing the control channel interference in the device.

The invention relates to an integrated gate-commutated thyristor (IGCT)-based hybrid cascaded H-bridge multi-level high-voltage inverter, which belongs to the technical field of electric drive. The inverter comprises a rectification unit, a DC unit, an inversion unit and a dv/dt filter, wherein the secondary side of a multi-winding rectifier transformer is connected with the input of the rectification unit; the output of the rectification unit is connected with the input of the DC unit; the output of the DC unit is connected with the inversion unit; and the output of the inversion unit is connected with the dv/dt filter. The inverter solves the problem that 10 kV high-voltage high-capacity output is obtained without realizing direct series connection by IGCT devices, less impacts a power grid in a working process, increases the sine degree of output voltages, has relatively lower difficulties in control and enhanced reliability, improves the working stability of a system, effectively inhibits current harmonics on a power grid side, and makes the distortion rate of line current on an input side meet standard requirements.

The invention discloses a plasma ignition and combustion stabilization device for IGBT (insulated gate bipolar transistor) rectification power supply. The plasma ignition and combustion stabilization device for the IGBT rectification power supply comprises a collision type pulverized coal concentration fractional combustion pulverized coal burner and a plasma spray gun, wherein the plasma spray gun generates high-temperature flame at the temperature of about 4000DEG C to ignite pulverized coal in an inner-layer combustion chamber of the pulverized coal burner; heat released from the burning of the pulverized coal in the inner-layer combustion chamber then ignites pulverized coal in an outer-layer combustion chamber to realize the stable combustion of pulverized coal flame; the collision type pulverized coal concentration fractional combustion pulverized coal burner comprises a primary air dust inlet, a straight pipe section, a taper pipe section, an outer nozzle, a collision concentration block, a collision concentration ring, the inner-layer combustion chamber, the outer-layer combustion chamber, an inner-layer combustion chamber disturbance block, an outer-layer combustion chamber rear disturbance block and an outer-layer combustion chamber front disturbance block; and the plasma spray gun comprises a cathode, a magnetic field coil, a spiral air chamber, an anode, a nozzle and a gun body. The plasma ignition and combustion stabilization device for the IGBT rectification power supply is applied to the starting ignition and the combustion stabilization stage of a pulverized coal fired boiler to replace the traditional big oil gun ignition and combustion stabilization mode, coal is used for replacing oil, and therefore the purpose of saving cost is achieved.

The low-harmonic AC motor controller includes monochip microprocessor MCU, zero-crossing detection circuit, control input circuit, SCR drive circuit, bi-directional SCR and power circuit. By means of zero-crossing triggering to alter the conducting in set period and phase shift triggering, the on/off of the bi-directional SCR is controlled to output continuously adjustable voltage. The control process includes the following steps: initializing before reading the set output power, performing the output power control operation, and producting interruption by the MCU after the zero-crossing detection circuit detects the AC zero-crossing signal to output triggering pulse. The controller and the control method make full use of the zero-crossing triggering and phase shift control, reduce greatly the harmonic and electromagnetic radiation, and control the output of great power AC motor in continuously adjustable mode radically.

The invention discloses a radio-frequency circuit and a method for reducing harmonic interference of the radio-frequency circuit. The circuit comprises a radio-frequency transceiving module, a matching module, a shunt switch and a filter module; one end of the matching module is connected with the radio-frequency transceiving module, and the other end is connected with the filter module via the shunt switch. The method comprises the following steps: S10, detecting the frequency of signals; and S20, selecting a signal channel according to the frequency detection result of the signals. The radio-frequency circuit can recognize signals and transmit the signals in different channels, and can further filter more harmonic interference generated therein, thus greatly reducing harmonic power no matter on conduction or coupling, and solving the problem of electromagnetic compatibility stray.

The invention belongs to the technical field of nervous system disease electrical stimulation, relates to a biological tissue time domain interference electrical stimulation device and a using methodthereof. The time domain interference electrical stimulation device comprises an AC signal source, a signal filtering module, a voltage control conversion module, a linear power source and a power source filtering module; two pairs of stimulation electrodes are attached to a body surface of a tissue to be stimulated, and two sinusoidal alternating electric fields at the frequency f and the frequency f+Delta f are applied to the two pairs of electrodes respectively, and when the two electric fields with similar frequencies meet, an interference phenomenon in the time domain can occur, and an envelope electric field is formed; and the frequency of the envelope electric field is the frequency difference between the two sinusoidal alternating electric fields. The electrical stimulation changepeak of the envelope electric field can be intensely focused in a specific region of the tissue in a spatial dimension through the time domain interference technique, so the purpose of non-invasive and precise regulation of electrical stimulation of a tissue targeted region only by adjusting the positions of the surface mount electrodes and the stimulation current ratio of the two pairs of electrodes.

The invention discloses a new energy power station dynamic reactive power compensation equipment application method. The improved content is as follows: (1) the dynamic reactive power compensation equipment is connected onto a low voltage-side bus of a three-winding boost transformer, the middle voltage side of the three-winding boost transformer is connected with gathered new energy electric power, and the two are isolated via the transformer; (2) voltage at the high voltage side of the new energy power station serves as reactive power needed by a calculation system for calculating reference voltage and control target voltage; and (3) a novel electronic current voltage combined transformer is applied to a measurement control system for the dynamic reactive power compensation equipment. In view of problems of poor operation stability of the new energy power station and disqualified electric power quality, a dynamic reactive power compensation configuration technology which can be applied to grid-connected power generation of the new energy power station and meet grid requirements is brought forward, a dynamic reactive power compensation equipment mounting site is changed, the new energy collecting system and the reactive power compensation equipment can be effectively isolated, the problems of operation stability of the new energy power station compensation equipment and electric power quality can be solved, and operation stability of the reactive power compensation equipment is improved.

The invention relates to a light-adjustable light-emitting diode (LED) drive circuit. The light-adjustable LED drive circuit is strong in anti-electromagnetic interference, high in power factor and high in reliability. The light-adjustable LED drive circuit comprises an anti-electromagnetic interference unit used for filtering external electromagnetic interference, a power factor correction unit used for improving the power factors of a power supply, a bridge rectifier circuit used for converting alternating current electric energy into direct current electric energy, a light modulator used for modulating voltage input into a voltage transformation rectifying circuit, a drive unit used for supplying electric energy to the light modulator, a voltage transformation rectifying circuit providing work current for an an LED light-source unit, a feedback circuit used for feeding back the work voltage of the voltage transformation rectifying circuit to a switch control circuit, the switch control circuit used for controlling output current of the voltage transformation rectifying circuit, and the LED light-source unit.

The invention relates to application of high-voltage variable-frequency control system in mine winder. Wherein, with asynchronous motor flexible draught closed loop as control strategy, generating proper frequency and amplitude and three-phase sine signal command by the controller according to error between given and feedback rotation speeds to send to high-voltage frequency converter to output ac power accorded with said request to drive motor with running performance rigorous coincidence with request; using IGBT chopping-wave resistance braking mode or of regenerative braking controlled rectifier for motor electric brake. This invention improves speed regulation quality of winder obviously, saves 30-40% energy, increases power factor more than 0.96, and solves difficulty of high-voltage heavy-power motor in four operating conditions.

The invention provides a method for processing harmonic interference and a mobile terminal, wherein the method for processing the harmonic interference comprises: detecting a current working scene ofa radio system of the mobile terminal; and controlling the nonlinear device in the radio frequency system to operate in the linear region when harmonic interference is generated in the current workingscene of the radio system of the mobile terminal, wherein when the nonlinear device operates in the linear region, the input signal and the output signal of the nonlinear device are linearly correlated. The invention is capable of improving the linearity of the working state of the nonlinear device, thereby reducing harmonic interference and improving the radio frequency performance. Moreover, inthe embodiment of the invention, the radio frequency circuit is simple, and the circuit design cost may be saved.

The invention provides an antenna device and a mobile terminal. The antenna device comprises an antenna, a front end module, a first power amplifier, a first filter and an anti-interference module; the antenna is connected with the front end module, the front-end module and the first power amplifier are connected to form a first access, the front-end module, the first filter and the first power amplifier are connected in sequence to form a second access, and the anti-interference module is connected with the first power amplifier; and the anti-interference module is used for acquiring a working frequency band of a carrier in real time, controlling the first power amplifier to close the first access and open the second access when the working frequency band of the carrier satisfies a preset condition, and controlling the first power amplifier to open the first access and close the second access when the working frequency band of the carrier does not satisfy the preset condition. The antenna device provided by the invention has the beneficial effects of reducing the harmonic interference during carrier aggregation.

The invention discloses a method of determining generator grid connection synchronous closing pulse transmission time, which comprises steps: S100, grid voltage and generator-end voltage in each cycleare acquired; S200, the effective value of the difference between the grid voltage and the generator-end voltage in each cycle is calculated; S300, the effective values of the voltage differences inmultiple cycles are stored to form a voltage difference effective value sequence, and a time sequence with the values to be consistent with the effective value sequence is stored; S400, according to the voltage difference effective value sequence and the time sequence, the correlation coefficient between the voltage difference effective value sequence and the time sequence is calculated, and a linear fitting expression for the voltage difference effective value sequence and the time sequence is calculated at the same time; and S500, according to the correlation coefficient and the linear fitting expression, whether to transmit closing pulses is judged.

The invention discloses a method for controlling alternating current digital coding. A controller uses a power driver member to performing digital pulse coding on a trailing edge of positive and negative half waves of the alternating current, each half wave can be used for coding a coding bit, and a purpose of transmission of a digital controlled signal by using an AC power line. The provided controlling method uses the AC power line for transmission of the digital controlled signal, under condition that a control line is not added, digital control of loop equipment can be realized, fewer elements can be required by a system, and cost of the system is reduced. The digital coding method realizes accurate positioning control, compared with a phase-cut dimming system, the controlling method can greatly reduce harmonic wave interference, and can increase the reliability of the system.

The invention discloses an energy storage charging power supply device for connecting an electric automobile with an intelligent power grid. The energy storage charging power supply device comprises a power grid end filter circuit, a static switch, an active power factor correction circuit, an inversion circuit, a bus super capacitor, a bidirectional direct-current/direct-current (DC/DC) converter and a battery end filter circuit, wherein the static switch is connected with three-phase alternating current of the power grid through the power grid end filter circuit; the input end of the active power factor correction circuit is connected with the static switch, and the output end of the active power factor correction circuit is connected with the bus super capacitor; the bus super capacitor is connected with the static switch through the inversion circuit, and then is connected with the battery end filter circuit through the bidirectional DC/DC converter; the battery end filter circuit is connected with a power battery; and the static switch, the active power factor correction circuit and the inversion circuit control the transmission direction of energy between the power grid and the power battery. According to the energy storage charging power supply device, large-capacity batteries can be charged quickly; furthermore, the energy storage charging power supply device has high charging efficiency and a rational design, and is convenient to use.

The invention provides a method for managing batteries of electric bicycles by using a computer. The method comprises the following specific step: recognizing identity information of every battery. Unusual conditions of charging saturability, over-fast descending of electric quantity of the batteries and the like of the batteries can be monitored, charging can be implemented by different staged charging methods, the problem of vulcanization of the insides of storage batteries which are lack of electricity deeply is eliminated, moreover, by adjustment, harmonic interference is low, flexible boosting and voltage-reduction output of output direct-current voltage can be realized, management of different types of batteries in a large range is implemented, and the service lives of the storage batteries are prolonged.

The invention provides a method for reducing coexistence interference of multiple networks and a terminal, and the method comprises the steps: obtaining a first working channel of a first network anda second working channel of a second network if the terminal employs the first network and the second network for communication at the same time; if the first working channel and the second working channel meet the harmonic interference condition and the harmonic noise of the receiving signal of the interfered network is greater than a preset threshold, adjusting a power amplifier in a signal transmitting link of the interfered network so as to reduce the harmonic noise of the receiving signal of the interfered network; wherein the interference network is the network with the minimum frequencyof the frequency band where the working channel is located in the first network and the second network, and the interfered network is the network with the maximum frequency of the frequency band where the working channel is located in the first network and the second network. According to the method, by improving the linearity of the power amplifier, the harmonic noise of an interfered network receiving signal is reduced, so that the terminal performance is improved.

The invention discloses a micro-grid island detection method and system. The method comprises the following steps that the voltage of a common connection point is collected, and the phase and frequency are obtained; whether an island phenomenon occurs is determined, if YES, the method is completed, and otherwise, a next step is followed; and a disturbance current is input, the voltage of the common connection point is collected again, whether the island phenomenon occurs is determined again, if YES, the method is completed, and otherwise, the first step is returned to. The system comprises a PWM driving module, a collection module and an island detection module, the collection module obtains the voltage, phase and frequency of the common connection point, and sends the voltage, phase and frequency to the island detection to compare the frequency and voltage of the power grid, a detection signal is sent to the PWM driving module, and thus, an inverter of a distributed power generation system is controlled, and the disturbance current waveform corresponding to output of the inverter is generated. Thus, micro-grid island detection can be realized rapidly, the validity of island detection can be still ensured under the condition of distributed energy devices, and interference of harmonic waves is reduced.