12results about How to "Harmonic suppression" patented technology

The invention relates to a model prediction fault-tolerant control method and system for a dual three-phase permanent magnet synchronous motor, and the method comprises the steps: estimating the lumped disturbance in the operation process of the motor in real time based on an extended state observer, and carrying out the feed-forward compensation of the reference voltage of the motor according to the lumped disturbance information; and based on the compensated voltage reference value, constructing a dynamic voltage vector set and correcting an initial voltage vector set, searching an optimal voltage vector in the dynamic voltage vector set, and driving the motor through three-phase decoupling space vector pulse width modulation. According to the field loss fault-tolerant control strategy designed by the invention, phase current harmonics caused by local field loss faults of the dual three-phase permanent magnet synchronous motor can be effectively suppressed, and the steady-state precision and the dynamic response capability of the system under the local field loss faults are enhanced.

The application provides a novel dead-time adaptive control method and device for a bridge arm topology. When complementary driving, the first dead-time is shortened as much as possible to reduce the dead-time freewheeling loss and effectively reduce a large number of harmonics caused by the dead-time insertion under the premise of avoiding bridge arm shoot-through, thereby improving the operation stability of an electrical system. Meanwhile, the second dead-time is dynamically adjusted according to the load current change to ensure that the second dead-time value can eliminate the output capacitor loss and reduce the dead-time freewheeling loss in the full power range, thereby improving the efficiency. Moreover, the second dead-time is too large to affect the output waveform quality of the circuit, and therefore, the second dead-time harmonic restriction is added to relieve the contradiction between the efficiency and the reliability.

This application provides a method and apparatus for suppressing current harmonics in an electrolytic capacitor-free drive system, relating to the field of permanent magnet synchronous motor drive control, and used to improve grid-side current quality. The method includes: acquiring a sawtooth wave of the same frequency, which is generated based on the LC resonant frequency; comparing the sawtooth wave with a given value to obtain a rectangular wave, and amplifying the rectangular wave to obtain a given damping pulse; shifting the phase of the given damping pulse according to the three-phase grid-side current to obtain an applied damping pulse; obtaining an α-axis voltage compensation component and a β-axis voltage compensation component based on the applied damping pulse; superimposing the α-axis voltage compensation component onto the α-axis voltage to obtain an α-axis voltage command; superimposing the β-axis voltage compensation component onto the β-axis voltage to obtain a β-axis voltage command; and applying the α-axis voltage command and the β-axis voltage command to a space vector pulse width modulation (SVPWM) inverter.

The utility model relates to the field of microwave communication, and specifically relates to a circuit for improving broadband ping-pong local oscillator output amplitude consistency. Comprising a first attenuator, a programmable frequency divider, a first filter, a first amplifier, a second attenuator, a second filter, a second amplifier and a third filter which are sequentially connected end to end, the input end of the first attenuator is connected with the output end of the ping-pong local oscillator; and the programmable frequency divider is configured to be in a 1 frequency division mode and is used for carrying out amplitude stabilization processing on the signal output by the first attenuator. According to the invention, the consistency and stability of the output amplitude are significantly improved. The circuit design is simplified, the debugging difficulty is reduced, and the overall performance of the system is improved, so that the system is more suitable for the requirements of a modern microwave communication system.

The invention relates to the technical field of motors and magnetic fluids, in particular to an axial flux permanent magnet motor rotor passive radial restraining and limiting method based on a stator back side magnetic fluid, a magnetic fluid forming limiting assembly is arranged on the back side of a stator, the magnetic fluid forming limiting assembly corresponds to the back face of a stator magnetic flux area, and an annular back side cavity area is formed; magnetic fluid is introduced into the back side cavity area, and the magnetic fluid is preliminarily distributed and attached to the back face area corresponding to the teeth / poles of the stator under the static or low-speed condition; when the motor runs, a rotating magnetic field generated by the rotor is utilized to magnetize the magnetic fluid and orientate the magnetic fluid along magnetic lines of force, so that the magnetic fluid is attached and keeps continuity under the action of the magnetofluid forming and limiting assembly; when the rotor generates radial eccentricity or pitching swing, a radial restoring force and a limiting effect on a boundary are generated by virtue of a coupling effect of a rotating magnetic field and fluid viscosity, so that passive radial constraint and limiting on the rotor are realized.

This invention relates to a speed control method and electronic device for permanent magnet synchronous motors (PMSMs) based on singular perturbation theory. The method includes: establishing a singular perturbation model of the PMSM and decoupling it into a fast-changing subsystem and a slow-changing subsystem; constructing an amplitude control set model predictive controller to obtain a voltage amplitude candidate set and establishing a current prediction model; calculating a q-axis current reference value based on a deadbeat controller; constructing a cost function based on the q-axis current reference value; using the cost function and the current prediction model to traverse the voltage amplitude candidate set; selecting the voltage combination with the minimum cost function as the optimal voltage control signal; and driving the PMSM based on the optimal voltage control signal. Compared with existing technologies, this invention has advantages such as improved current tracking accuracy, suppression of harmonics and torque ripple, ensuring rapid tracking of speed commands, and simultaneously meeting the requirements of high dynamics, high precision, and robust control of motor speed.

The utility model discloses a kind of intermediate frequency DC reactors, including magnetic core, coil, input conductive row and output conductive row, the magnetic core is oppositely equipped with two iron columns, the coil is equipped with two groups and is respectively wound on the two iron columns of the magnetic core, the coil is wound with thin wide metal foil and is formed, the input conductive row is located in the lower portion of this intermediate frequency DC reactor and is connected with the coil, the output conductive row is located in the upper portion of this intermediate frequency DC reactor and is connected with the coil. The utility model winding loss is small, and the heat dissipation performance is excellent, compact structure, high reliability, strong environmental adaptability, can be adapted to intermediate frequency working condition.

The utility model discloses a frequency hopping frequency source module based on DDS relates to microwave radio communication technical field, including crystal oscillator, power divider and frequency mixer, and power divider and frequency mixer are connected in parallel through first branch and second branch, and first branch includes FPGA chip, PLL chip, DDS chip and first filter who connects in order series connection, and FPGA chip and power divider first output electric connection, and first filter and frequency mixer first input electric connection, and the second output of FPGA chip and the frequency control input of DDS chip electric connection. The utility model discloses the hardware construction under relevant layout, still makes it have the advantage that the output frequency coverage is wide under the original already having the advantage that the frequency switching speed is fast, and the frequency resolution is high.

The application provides a control method and device of a permanent magnet synchronous motor and the permanent magnet synchronous motor, and the method comprises the following steps: S1, obtaining a phase-lagged bus voltage sampling signal by sampling and filtering a bus voltage of the permanent magnet synchronous motor; S2, performing phase compensation filtering on the bus voltage sampling signal to obtain a compensated bus voltage; S3, calculating a real-time duty cycle signal according to a Park inverse transformation output voltage and the compensated bus voltage; and S4, controlling an inverter according to the real-time duty cycle signal to drive the permanent magnet synchronous motor to operate. The application proposes a phase compensation algorithm by using the repetitive periodicity of the bus voltage, so that the compensated bus voltage value is closer to the actual bus voltage value, and the accuracy of bus voltage measurement is improved. The harmonics of the motor current can be effectively filtered out.

The application claims a segmented R-2R inverting ladder resistor network with high spurious-free dynamic range, which improves the spurious-free dynamic range (SFDR) of the circuit by segmenting the R-2R inverting ladder resistor network and performing non-overlapping rotation selection processing on the high-bit segment resistor network. The circuit mainly comprises: a thermometer decoder for converting a high-4-bit binary code into a 15-level thermometer code; an accumulator for accumulating the high-4-bit binary code to generate a shift control signal (also called a pointer) required by a logarithmic shifter; a logarithmic shifter for performing a shift operation according to the shift control signal input by the accumulator and the thermometer code input; a level holding circuit for compensating for the level lost during the shift operation of the logarithmic shifter; a latch for time-domain alignment of the signals of the low-12-bit and high-4-bit; and a segmented R-2R inverting ladder resistor network for receiving the digital signal of the latch and then decoding the digital signal.

The application discloses a kind of cross interconnection ground cable metal sheath loop resistance detection method and system, it is related to ground loop resistance detection technical field.By at least two different frequency of different frequency excitation current signals to the cable metal sheath loop to be measured time-sharing injection, acquisition voltage and current response signal and are conditioned and analog-digital conversion obtain digital sequence;Signal is handled under each frequency to obtain pure waveform, and calculate complex impedance according to this, and loop resistance is solved based on the complex impedance of at least two frequencies.In denoising process, signal is decomposed into intrinsic mode component using variational mode decomposition, effective component and noise component are separated by combining effective index value, and effective component is finely denoised and reconstructed.The method can effectively suppress power frequency, harmonic and random interference, reduce waveform distortion, improve the accuracy and stability of loop resistance measurement under complex field environment.

The invention provides a grid-connected inverter harmonic suppression method based on double-vector model predictive control, and the method comprises the steps: building an inverter prediction model under an alpha-beta static coordinate system, separating an output current into a fundamental component and a harmonic component, and carrying out the prediction control of the fundamental component and the harmonic component; a dual-target optimization function containing a fundamental wave weight coefficient eta and a harmonic wave weight coefficient gamma is constructed, minimization of an error area between PCC harmonic current and a zero axis is taken as a harmonic suppression target, and a dual-vector model is combined to predict and control a dynamic optimal voltage vector and action time thereof, so that coordinated optimization of fundamental wave power transmission and harmonic suppression is realized. The method can effectively reduce the total harmonic distortion rate at the PCC, improves the electric energy quality of a multi-inverter parallel system, and is suitable for an alternating current bus system containing multiple harmonic sources.