10results about How to "Harmonic reduction" patented technology

The application discloses a random rotation DEM structure for reducing switch activity, comprising a digital-to-analog converter, a digital input of the digital-to-analog converter is divided into an input code and a random rotation number, the random rotation number is input into a switch activity reduction structure through a barrel shifter output result delayed by a D flip-flop for one period, a feedback output of the switch activity reduction structure is fed back to the barrel shifter as an input, and an output of the barrel shifter after rotation controls corresponding switches and is connected to a corresponding cell array. The application uses input data to replace a pseudo-random number generator, and uses relatively simple logic to realize a switch activity reduction function, so that the complexity is reduced.

This application provides a radio frequency (RF) device and its inductor. The RF device includes a power amplifier circuit, a signal coupling circuit, an extraction circuit, and a harmonic filter circuit. The power amplifier circuit amplifies a differential signal to output a signal to be filtered. The signal coupling circuit includes a primary inductor and a secondary inductor. The signal coupling circuit receives the signal to be filtered through the primary inductor and outputs a single-ended signal from the secondary inductor. The extraction circuit has a center tap. The extraction circuit couples with the primary inductor and outputs a common-mode signal from the center tap. The harmonic filter circuit performs harmonic filtering on the single-ended signal based on the common-mode signal, so that the secondary inductor of the signal coupling circuit outputs a filtered signal.

The application belongs to the technical field of communication, and particularly relates to a radio frequency front-end module and a radio frequency chip. The radio frequency front-end module comprises a power amplification circuit, a transceiving switch circuit, a filter circuit, an antenna switch circuit, a matching adjustment circuit, a low-noise amplification circuit and an antenna end; the antenna switch circuit comprises a switch unit, a coupling unit, a first trap unit, a second trap unit, a third trap unit, a first inductor and a second inductor; a first end of the switch unit is used as a first end of the antenna switch circuit, and a second end of the switch unit is connected with a first end of the coupling unit; a second end of the coupling unit is connected with a first end of the first trap unit, and the coupling unit is used for extracting part of power in a radio frequency signal for detection and calibration. Compared with the prior art, the radio frequency front-end module of the application precisely suppresses and blocks low-frequency multiple harmonics, cooperates with a high-low frequency dual-module filtering scheme, and greatly improves the harmonic suppression capability.

The invention discloses a permanent magnet synchronous motor and a single-resistor current sampling method. The permanent magnet synchronous motor controls a three-phase inverter based on an SVPWM strategy, and the method comprises the following steps: in a current control period, acquiring flow directions of A, B and C three-phase current; according to the flow direction of the ABC three-phase current and a sector where a target voltage vector is located, whether the minimum time window of single-resistor sampling in the current control period can cancel dead time or not is determined; and according to the determined minimum time window, determining whether to adjust the two-phase sampling in the current control period. According to the scheme provided by the invention, sampling can be carried out by directly utilizing the dead time under some conditions, so that the number of times of PWM waveform adjustment is reduced, the stability of the system is improved, and the collected current is closer to the same moment.

This invention discloses a scalable power very low frequency (VLF) transmitter device and its control method. It consists of multiple individual cabinets, with multiple units sharing a single main control system, facilitating expansion and allowing for power level adjustments, improved waveform quality, and reduced output waveform harmonics. The input terminals of multiple individual power cabinets can be connected in parallel to DC or AC power supplies, and the output terminals are connected in series to the load. Each cabinet includes a switching module, a voltage conversion module, an adjustable voltage module, multiple switching signal modules, multiple multi-tap high-frequency transformers, and a corresponding number of bypass switches. The unique design of the switching signal modules facilitates online expansion and replacement. The high-frequency transformers are multi-tap high-frequency transformers; adjusting the tap positions allows for graded adjustable output voltage after multiple units are connected in parallel. The main control system includes a command control unit, a stepped waveform generation and expansion unit, a storage unit, and a communication unit. The main control system can multiply the comparison value and pulse quantity based on the individual unit comparison value using interpolation methods to provide pulse signals to the switching signal modules.

A method and a sensor system for calibrating a magnetic sensor system are provided. The position of the magnetic structure varies within a calibration range when measuring at least four components of the magnetic field generated by the magnetic structure having a main orbit and a nonius orbit. The uncalibrated position of the structure is determined and compared with a corresponding reference position. A periodic function is obtained by calculating two coefficients of a function such that the function applied to the uncalibrated position minimizes the error caused by the comparison with the reference position.

The application provides a motor rotor, a self-starting synchronous reluctance motor, a compressor and a motor rotor. The motor rotor has a slit slot, a second filling slot and a first filling slot on a first rotor lamination. An outer magnetic barrier layer includes the first filling slot, and an inner magnetic barrier layer includes the slit slot and the second filling slot at both ends of the slit slot. Between the second filling slot and the slit slot in the same layer of the inner magnetic barrier layer, there is a separation rib. A side of the separation rib close to an outer circle of the rotor has a center point in an axial plane. The distance between two center points corresponding to two separation ribs in any two adjacent layers of magnetic barrier layers along a d-axis direction is L. The maximum distance between the filling slots in the two adjacent layers of magnetic barrier layers along a q-axis direction is W, and 0<=L<2W. According to the application, the saturation degree of the magnetic conduction channel between the filling slots can be reduced, the motor harmonics can be reduced, the torque ripple can be reduced, the harmonic loss can be reduced, the motor efficiency and the operation stability can be improved.

This invention provides a filtering method, apparatus, frequency converter, and storage medium. The filtering method includes: obtaining a filtering capacitor based on the cable length between the frequency converter and the motor; obtaining a filtering inductor based on the motor's rated parameters; and filtering the voltage signal to be output to the motor using the filtering inductor, the filtering capacitor, and a pulse width modulation waveform determined based on both, to obtain a filtered voltage signal. This invention improves the accuracy of filtering parameter calculation, reduces computational complexity, lowers the waveform distortion rate and phase voltage amplitude of the input voltage signal at the motor end, and reduces harmonics in the voltage signal.

The application discloses a kind of permanent magnet synchronous motor double vector model predicted current control methods considering dead zone, it is related to motor drive control technical field, comprising the following steps: S1, establish PMSM discrete prediction model and sampling: derivation current prediction equation;S2, based on the classification strategy of cost function and torque current: voltage vector is divided into overshoot vector group and under shock vector group;S3, double vector screening strategy based on classification strategy: screening out optimal double vector candidate combination;S4, dead zone determination and beatless time synthesis: output final switch control pulse.The application adopts the above-mentioned permanent magnet synchronous motor double vector model predicted current control method considering dead zone, reduces the current distortion caused by dead zone effect, solves the local optimal problem in traditional strategy, and greatly reduces the calculation burden, provides a kind of efficient control scheme with high dynamic response, global steady-state accuracy and low harmonic characteristic for ship PMSM propulsion system.