16 results about "Harmonic cancellation" patented technology

The invention discloses a high-linearity low-noise amplifier based on harmonic suppression, relates to the field of communication and the technical field of electronic devices, and is used for solving the problem that the noise coefficient of an existing Darlington structure is large. Comprising a noise matching and input matching network, a linearity enhancement structure, a negative feedback structure and a pre-distortion structure. Wherein the linearity enhancement structure at least comprises a first amplification transistor and a second amplification transistor which are arranged in parallel, and is used for improving the linearity of the circuit through harmonic cancellation; the negative feedback structure is connected with the noise matching and input matching network and the pre-distortion structure and is used for expanding circuit bandwidth and optimizing output matching; the pre-distortion structure is used for stabilizing the bias voltage of the third amplification transistor. According to the invention, the linearity of the whole circuit is effectively improved, and the source microstrip lines of the two circuits are utilized to improve the minimum noise matching and improve the noise performance. Noise is reduced, linearity is improved, low-frequency gain is suppressed, and bandwidth of the whole circuit is improved.

The invention discloses an axial flux permanent magnet synchronous reluctance motor rotor based on modular harmonic counteracting, the rotor is designed in a three-in-one mode of structure modularization, magnetic barrier gradient and phase computable dislocation, a rotor assembly is formed by splicing N fan-shaped rotor modules along the circumference, and the adjacent modules are provided with optimal dislocation angles calculated according to the harmonic counteracting principle. The sum of target harmonic magnetic field vectors generated by each module is zero; a U-shaped magnetic barrier array of which geometric parameters are monotonically changed in a gradient manner is arranged in the fan-shaped rotor module, and a permanent magnet group is embedded in the fan-shaped rotor module; main electromagnetic harmonic waves are offset from the source, magnetism gathering and resistance increasing functions are decoupled, the mechanical robustness and the electromagnetic performance of the motor are improved, meanwhile, overall machining is converted into standardized module assembling, the manufacturing cost and the maintenance difficulty are reduced, different motor pole numbers can be flexibly adapted, and the service life of the motor is prolonged. The method is suitable for high-end application scenes such as new energy automobiles, industrial driving and aerospace.

This invention discloses a general construction method for a bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation. The method consists of three levels: preliminary optimization, constraint 1 for the cancellation of armature magnetic field harmonics and permanent magnet harmonics before modulation, and constraint 2 for the cancellation of armature magnetic field harmonics and permanent magnet harmonics after modulation. Preliminary optimization can only reduce the pulsation generated by the fundamental wave of the levitation magnetic field and the stationary wave of the permanent magnet. Based on this, constraint 1 is proposed to reduce the levitation force pulsation generated by the armature magnetic field harmonics and permanent magnet harmonics before modulation, and constraint 2 is proposed to reduce the levitation force pulsation generated by the armature magnetic field harmonics and permanent magnet harmonics after modulation. Through the principle of global fundamental harmonic cancellation, this invention effectively reduces the levitation force pulsation of the bearingless magnetic gear double-sided motor, overcoming the shortcomings of traditional and existing levitation motor construction methods.

The application belongs to the technical field of electric machines, and discloses a magnetic suspension fan variable frequency driving device and a harmonic suppression method; the method comprises the following steps: judging a transient operation process and activating a phase compensation mechanism by monitoring the state of the electric machine in real time, extracting harmonic components in real time and updating a weight vector to obtain harmonic currents of different orders; meanwhile, a phase compensation amount is dynamically obtained based on a pre-built control loop phase lag atlas, an anti-phase harmonic voltage is calculated in combination with the harmonic currents and the compensation phase, and the variable frequency device is injected through a space vector pulse width modulation method to realize accurate harmonic cancellation; torque safety monitoring is also independently operated in parallel in the whole process, the electromagnetic torque and its change rate are detected in real time to perform safety logic determination, and a protection action is triggered when the limit is exceeded; the application can realize accurate cancellation of anti-phase harmonics and actual interference harmonics in the transient process, significantly reduce the instantaneous impact of the electromagnetic torque, and effectively improve the operation stability and reliability of the magnetic suspension fan variable frequency driving system under transient working conditions.

A radio frequency circuit includes a transmit power amplifier, a differential transmit signal path having first and second paths, and first and second baluns. The first balun can be configured to convert a single ended transmit signal into a differential transmit signal, and the second balun can be configured to convert the differential transmit signal back to a single ended transmit signal. The circuit can also include a pair of transmit filters between the first and second baluns and including a first transmit filter connected in the first path and a second transmit filter connected in the second path. The second balun cancels harmonic noise generated by the pair of transmit filters.

The invention relates to the technical field of rail transit vehicle electrical control, and discloses a PFC cooperative control method and system of a rail transit multi-motor driving system. According to the method, parameters of multiple motors and a vehicle-mounted power grid are collected in real time, THD is predicted based on a harmonic superposition model, the standard exceeding risk is judged, PFC control parameters are dynamically distributed in combination with model prediction control and self-adaptive harmonic cancellation logic, the actual THD and power factors are monitored after synchronous issuing, and closed-loop optimization is formed; the system comprises a signal acquisition module, a global optimization algorithm module, an execution control module and a monitoring feedback module. The method can reduce the THD of multi-motor parallel operation by more than 30%, improves the power factor to be greater than or equal to 0.98, adapts to load fluctuation and motor switching working conditions, is compatible with existing hardware, is low in improvement cost, and is suitable for rail transit vehicles such as subways and high-speed rails.

This invention belongs to the field of sensors and signal processing, specifically relating to a wavelet kernel-scale sensitivity-guided denoising method for abrasive particle induced voltage signals. The method includes: acquiring abrasive particle induced voltage signals and performing harmonic cancellation to obtain a preprocessed signal; constructing a wavelet kernel function and calculating a kernel-scale guided spectrum using it and the preprocessed signal; constructing a sparse joint denoising model based on the kernel-scale guided spectrum; processing the sparse joint denoising model to obtain a convex optimization objective function; solving the convex optimization objective function using an adaptive step-size gradient descent method and an adaptive iterative shrinking threshold method to obtain a weight vector characterizing the distribution of abrasive particle characteristic signals; binarizing the weight vector characterizing the distribution of abrasive particle characteristic signals to obtain a feature indicator vector; performing a Hadamard product between the feature indicator vector and the preprocessed signal, followed by low-pass filtering to obtain a denoised signal. This invention can adaptively and non-destructively enhance and denoise abrasive particle characteristic signals under strong interference environments.

The invention discloses a real-time harmonic suppression and compensation method for a DAC output end, and the method comprises the steps: collecting harmonic characteristic parameters of an output signal through a high-precision DAC calibration test platform, and carrying out the cooperative processing of a cascade notch dynamic harmonic cancellation model, a frequency band weight adaptive distribution model and a nonlinear even harmonic enhancement algorithm, harmonic feature extraction, model parameter configuration, weight distribution, even harmonic enhancement, dynamic offset and real-time feedback correction are sequentially completed. According to the method, model parameters are dynamically adjusted to adapt to a complex harmonic scene, the processing precision is improved by means of multi-model linkage and real-time feedback, the method has the advantages of being high in adaptability, accurate in processing and good in stability, DAC output signal distortion can be greatly reduced, the signal purity and reliability are improved, and the method is suitable for large-scale popularization and application. The method is suitable for communication, industrial control, test measurement and other environments with strict signal precision requirements.

The invention belongs to the technical field of motors, and discloses magnetic suspension fan variable frequency driving equipment and a harmonic suppression method. The method comprises the following steps: judging a transient operation process and activating a phase compensation mechanism by monitoring a motor state in real time, extracting a harmonic component in real time and updating a weight vector to obtain each harmonic current; meanwhile, dynamically obtaining a phase compensation amount based on a pre-established control loop phase lag map, calculating an anti-phase harmonic voltage in combination with the harmonic current and a compensation phase, and injecting the anti-phase harmonic voltage into a frequency converter through a space vector pulse width modulation method to realize accurate harmonic cancellation; torque safety monitoring is independently operated in the whole process in parallel, the electromagnetic torque and the change rate of the electromagnetic torque are detected in real time for safety logic judgment, and a protection action is triggered when the limit is exceeded; according to the method, the reverse-phase harmonic waves and the actual interference harmonic waves in the transient process can be accurately offset, the instantaneous impact of the electromagnetic torque is remarkably reduced, and the operation stability and reliability of the variable-frequency driving system of the magnetic suspension fan under the transient working condition are effectively improved.

Apparatus and methods may include receiving a square wave having a frequency at an input of a harmonic cancellation (HC) sine wave generator; receiving a clock signal having a clock frequency at a clock input of the HC sine wave generator; generating, using one or more delay components of the HC sine wave generator, one or more delayed square waves based on the received square waves and the clock signal; and amplitude scaling the square wave and the one or more delayed square waves using a plurality of taps of the HC sine wave generator to produce a plurality of amplitude scaled square waves. The method may include adding the plurality of amplitude scaled square waves using summing circuitry of the HC sine wave generator to generate a sine wave at an output of the HC sine wave generator, the sine wave having a tone at the frequency of the square waves and a suppressed signal strength at a selected harmonic of the frequency.

The present disclosure relates to a resonator with intrinsic second harmonic cancellation. The resonator can include a first electrode, a second electrode, and a piezoelectric material between the first electrode and the second electrode, where the piezoelectric material is formed by fabricating the piezoelectric material with a compression axis vector (C-axis vector) oriented along a first direction and applying an electric field across the piezoelectric material to modify the direction of the C-axis vector to be oriented along a second direction. The second direction can be antiparallel to the first direction.

This invention provides a harmonic suppression method for a T-type three-level inverter using active reconfiguration of switch combinations, relating to the field of power electronics technology. Addressing the shortcomings of existing methods that rely on precise modeling and have poor dynamic adaptability, this method acquires the three-phase output voltage in real time and extracts the harmonic deviation vector. Based on its direction angle, a lookup table is used to select the corresponding switch combination as the modulation mode. The drive pulses of the selected switches are actively shielded to change the available set of the basic voltage vector. A linear equation system for the modulation time correction is established, and the SVPWM modulation time is reconstructed. A compensation voltage opposite to the original harmonic deviation is synthesized, and this process is iterated in a closed loop until the harmonic deviation is below a threshold. This method does not change the main circuit, does not rely on precise mathematical models, and does not affect the fundamental frequency control. It achieves directional harmonic cancellation through dynamic reconfiguration of switch combinations, effectively reducing the total harmonic distortion rate and adapting to high power quality scenarios such as motor drives and new energy grid integration.

The present application belongs to the technical field of power quality optimization, and discloses an M3C output power quality optimization method, system, device and medium, which comprises the following steps: acquiring an M3C output side electric signal in real time and converting it into a sampling sequence, extracting a harmonic error signal from the sampling sequence by using an adaptive filtering algorithm, and dynamically adjusting the step factor of the adaptive filtering algorithm according to the error signal; based on the harmonic error signal, generating a harmonic compensation signal for each bridge arm by using a bridge arm phase coordination strategy and superimposing the harmonic compensation signal on the basic modulation wave of the corresponding bridge arm; converting the modulation wave of each bridge arm after compensation and superposition into a switching driving signal, and realizing harmonic cancellation at the M3C output end by using the spatial phase redundancy between the bridge arms; and using passive filtering technology to assist in filtering the residual high-frequency harmonics in the M3C output waveform after harmonic compensation, so as to realize the optimization of the M3C output power quality. The adaptive harmonic extraction and bridge arm phase coordination compensation mechanism are introduced to realize the optimization of the output power quality.

The application discloses a double-branch second harmonic rectifier transmitter based on PIE modulation and a wireless power transmission system. The rectifier transmitter comprises a distribution and combination network, a first rectification branch and a second rectification branch. The first rectification branch and the second rectification branch respectively comprise a first rectification diode and a second rectification diode in reverse parallel connection and are respectively connected to a first direct-current load and a second direct-current load. The second direct-current load is controlled by a pulse interval modulation signal to realize switching between a first impedance state and a second impedance state; in the first impedance state, second harmonic components generated by the two rectification branches cancel each other out; in the second impedance state, the second harmonic cancellation state is destroyed, high-amplitude second harmonic pulses are formed, and the time interval between adjacent high-amplitude second harmonic pulses is used to represent the data to be transmitted. The application can realize second harmonic uplink communication while maintaining rectification energy output, and reduce the influence of communication modulation on wireless energy collection efficiency.

Devices and methods may include receiving a square wave having a frequency at an input of a harmonic-cancellation (HC) sine-wave generator; receiving a clock signal having a clock frequency at a clock input of the HC sine-wave generator; generating one or more delayed square waves based on the received square wave and the clock signal using one or more delay components of the HC sine-wave generator; and amplitude-scaling the square wave and the one or more delayed square waves using a plurality of taps of the HC sine-wave generator to produce a plurality of amplitude-scaled square waves. The method may include adding the plurality of amplitude-scaled square waves using summing circuitry of the HC sine-wave generator to produce a sine wave having tone at the frequency with suppressed signal strength at selected harmonics of the frequency of the square wave at an output terminal of the HC sine-wave generator.

The application discloses a harmonic elimination circuit, method and device, and relates to the technical field of circuits.The circuit comprises a controller, a harmonic elimination resistor and a switching circuit.The harmonic elimination resistor is connected to the neutral point of a voltage transformer and the ground respectively, and the switching circuit is connected in parallel with the harmonic elimination resistor.The controller controls the switching circuit to be turned off when ferromagnetic resonance is detected, so that the harmonic elimination resistor is connected to suppress resonance;and the controller controls the switching circuit to be turned on after the fault disappears, so that the neutral point is directly connected to the ground.The controller compares the neutral point current with a first threshold value to determine whether resonance occurs, and determines that the fault disappears when the current is less than a second threshold value.When the harmonic elimination resistor is a variable resistor, the controller adjusts the resistance value according to the current change rate and a pre-learned mapping relationship.The switching circuit can be a switch tube or a relay, and the controller controls the switch tube to be turned off or the relay coil to lose power to realize switching.The circuit can quickly suppress ferromagnetic resonance, guarantee system stability and improve fault handling efficiency.