5results about How to "Improve harmonics" patented technology

This invention relates to the field of inverter technology, and particularly to a heterogeneous power device hybrid inverter and its space vector modulation method. The heterogeneous power device hybrid inverter provided in this invention includes a first constant current source, a second constant current source, a main power inverter module, a secondary power inverter module, and a capacitive reactance module. The first constant current source is connected to the main power inverter module to provide current to the main power inverter module. The main power inverter module includes multiple silicon-based insulated-gate bipolar transistors (SBMTs) as main switching transistors, and the main power inverter module is connected to the capacitive reactance module. The second constant current source is connected to the secondary power inverter module to provide current to the secondary power inverter module. The secondary power inverter module includes multiple silicon carbide-based metal-oxide-semiconductor field-effect transistors (MOSFETs) as secondary switching transistors, and the secondary power inverter module is connected to the capacitive reactance module. The heterogeneous power device hybrid inverter and its space vector modulation method provided by this invention can balance high inverter frequency and low switching losses.

The invention belongs to the technical field of string adjustment, and particularly relates to a violin string tension adjustment control device which comprises an adjustment chamber, adsorption units are symmetrically arranged at one end of the adjustment chamber, positioning units are arranged on the sides, close to the adjustment chamber, of the adsorption units, an adjustment unit is arranged on one side in the adjustment chamber, and a feedback unit is arranged on one side of the adjustment unit. Through the lifting effect of the electric telescopic rod and the face-to-face or back-to-back movement between the idler wheels, lifting and sudden release of strings are achieved, then radial jumping of the strings is degraded and buffered through the multi-degree-of-freedom string roller, dominant impact between the lower electrode cap and the electrode ball is controlled through the prying roller short section, and therefore the electrode ball can be driven to move stably and stably. The high-frequency impact state between the strings and the long section of the prying roller is expressed, that is, impact feedback of the strings in a low-frequency state is explicitly and prominently expressed through an extended range, the change of tension is accurately sensed, excessive or insufficient adjustment is avoided, the overall tone balance is optimized, and the harmony degree and expressive force of the tone of the violin are improved.

This invention relates to the field of electric motors, and more particularly to an electric motor rotor. The electric motor rotor includes: a trapezoidal slot formed on the outer circumferential surface of the motor rotor, the trapezoidal slot having a base edge; a magnet slot, the axis of symmetry of the magnet slot passing through the center of the inner diameter of the motor rotor, the trapezoidal slot being formed on at least one side of the axis of symmetry of the magnet slot, the magnet slot having a first side line; and a magnetic stabilizing hole formed between the outer circumferential surface of the motor rotor and the magnet slot, the longitudinal axis of the magnetic stabilizing hole being perpendicular to the first side line, the magnetic stabilizing hole and the trapezoidal slot being on the same side of the axis of symmetry of the magnet slot, the axis of symmetry of the trapezoidal slot passing through the center of the inner diameter of the motor rotor, an angle α1 between the longitudinal axis of the magnetic stabilizing hole and the axis of symmetry of the trapezoidal slot, and an angle α2 between the longitudinal axis of the magnetic stabilizing hole and the axis of symmetry of the magnet slot, α1 and α2 satisfying 0.701≤(α1-α2) / α1≤0.958. This invention also relates to an electric motor. This invention can effectively reduce the no-load back EMF harmonics of the motor, improving motor efficiency and operational smoothness.

The present disclosure belongs to the technical field of permanent magnet synchronous motor control, and particularly relates to a kind of permanent magnet synchronous motor position sensorless control method and system, comprising: obtaining the stator current and stator voltage of permanent magnet synchronous motor, respectively calculate the first active flux linkage based on voltage model and the second active flux linkage under current model;The first active flux linkage and the second active flux linkage obtained are calculated to match error and inverter output voltage compensation term;According to the output voltage compensation term obtained, the driving signal of inverter is adjusted to realize the driving control of permanent magnet synchronous motor.The present disclosure identifies and compensates by constructing an adaptive observer, improving the running performance of the model method based on flux linkage at low speed.

The invention relates to the technical field of image enhancement, and provides an underwater image dual-path enhancement method based on wavelet domain diffusion and spatial domain collaboration, which comprises the following steps: acquiring and preprocessing an original underwater image, performing multi-stage discrete wavelet transform on each image, and decomposing to obtain a low-frequency component and a multi-layer high-frequency component; performing frequency domain enhancement on the low-frequency component and the multiple layers of high-frequency components, and outputting a frequency domain enhanced image; inputting the original underwater image into the spatial domain residual mapping network for color and contrast correction to obtain a spatial domain enhanced image; performing adaptive fusion on the original underwater image, the frequency domain enhanced image and the spatial domain enhanced image to generate a pixel-by-pixel weight and a global weight, performing weighted fusion on a frequency domain enhanced result and a spatial domain enhanced result based on the pixel-by-pixel weight and the global weight, and outputting a final enhanced image; and loading the trained model, and outputting a final enhanced image. According to the invention, high-quality integrated recovery of underwater image colors, illumination and details is realized.