37results about How to "Reduce waveform distortion rate" patented technology

The invention discloses a power cable field partial discharge signal noise reduction method. The method comprises the steps that S1 a field power cable partial discharge signal is collected, and digital processing is carried out to form the time domain signal f (t) of the field partial discharge signal; S2 the time domain signal f (t) is converted to a corresponding frequency domain function F (omega) through fast Fourier transform, and mathematical processing is carried out on the frequency domain function F (omega) to acquire a fast Fourier power spectrum described in the description; S3 anAGFCM algorithm is used to classify noisy signal power spectrum data into two categories; S4 narrow band interference peak is positioned; the positioned narrow band interference peak is compressed; inverse fast Fourier transform is carried out on P (omega) after narrow band interference peak filtering to acquire a narrow band noise filtered signal g (t); and S5 wavelet transform analysis is carried out on g (t); mother wavelet is selected; a threshold is determined; white noise is filtered out to acquire a final denoised signal. According to the invention, periodic narrow-band noise can be suppressed; the waveform distortion rate is reduced; and the signal-to-noise ratio of the denoising result is improved.

The invention discloses a pulse-width modulation (PWM) inverted power supply system and a PWM inverted power supply algorithm based on a fuzzy predictive control technology. The input is direct current (DC) voltage, and the input passes through a DC booster circuit, is subjected to ripple wave removal through a filtering circuit and passes through a DC/alternating current (AC) inversion circuit; the output is high-voltage AC, an AC voltage detection feedback circuit, an overcurrent detection feedback circuit, a DC detection feedback circuit, a DC voltage detection feedback circuit and other protection circuits are arranged in the circuit, when overcurrent and overvoltage are detected, a control chip obtains a reasonable dead-zone predictive control scheme through an algorithm according to data which is acquired in real time, the PWM driving pulse waveform is changed, and the working reliability of a switching device is effectively guaranteed; meanwhile, the conversion efficiency of a PWM inverter system is high, and the distortion rate of output waveform is reduced. The invention is applicable to fields of switching power supply inverters, solar inverted power supplies, small wind driven generator inverted power supplies and the like.

The invention relates to a generator, in particular to a high-power harmonic wave excitation generator which solves the problem of higher voltage waveform aberration rate of a triple harmonic wave winding and a primary winding of the existing harmonic wave excitation generator. The high-power harmonic wave excitation generator comprises a stator, a primary winding and a triple harmonic wave winding embedded in a stator groove, wherein the primary winding is a double-layer wave winding; the triple harmonic wave winding is a single-layer concentric type winding with different turns, i.e., in eight grooves under each pole pair of the triple harmonic wave winding, no conductors are arranged in a third groove and a seventh groove; the ratio of the number of turns of the single-layer concentriccoils in the first and fifth grooves to the number of turns of the single-layer concentric coils in the second, fourth, sixth and eighth grooves is 1:0.707 which is rounded; and the primary winding adopts a short-range winding. The waveform aberration rate of the triple harmonic wave winding can be reduced to 15 percent and the waveform aberration rate of the primary winding can be reduced by 4.8percent. The excitation generator is applicable to mining electric drive dumper lorries and also can be used in other fields of railway, generating plant, industrial and mining, and the like.

This invention relates to a continuous rotating type ac electric motor, particularly three phase, low wave form distortion, high efficiency ac electric motor being composed of a rotor and a stator. The stator comprises: a seat, a stator core and stator winding each of the three phase stator winding occupies one layer of stator core channel. On the cross-section of the stator core, the corresponding end points of three-layer winding are of 120 deg. intervals. This invention breaks-through prior art mode of single layer or double layers of stator winding of three-phase motor, so it can eliminating distortion wave form of three phase electric motor, the distortion rate is less than 2%. The efficiency of electric generation is greater than 95%, while the efficiency of electric motor is greater than 90%.

The invention aims to provide a low-spurious sinusoidal signal generator based on a multi-point compensation scheme. The low-spurious sinusoidal signal generator based on the multi-point compensation scheme comprises a main D/A conversion module and a high-speed D/A conversion module; the main D/A conversion module is a low-speed D/A converter having high effective bit, and is responsible for outputting sinusoidal waveform; the high-speed D/A conversion module generates a harmonic counteraction signal zeta(t), and is used for counteracting the harmonic component in the sinusoidal waveform generated by the main D/A conversion module; after being subjected to subtraction through an addition and subtraction operation circuit, the two signals are output; and thus, sinusoidal voltage output after harmonic counteraction is finally obtained. The low-spurious sinusoidal signal generator overcomes the disadvantage that both the effective bit and the conversion speed cannot be obtained at the same time in the prior art; when the harmonic component in the sinusoidal wave generated by the sinusoidal signal generator is effectively reduced, the A/D conversion speed of the sinusoidal signal generator can be ensured; and thus, sinusoidal wave signals having relatively low waveform deviation rate can be obtained.

The invention discloses a double-random SVPWM modulated SVG double-sequence synchronous control method, which comprises the following steps: 1. Detecting load current, SVG output current, DC side capacitance voltage and grid voltage; 2, compensate that positive sequence component and the negative sequence component respectively by adopting the positive and negative two-sequence control strategy; 3, acquiring a voltage command signal; 4, that drive signal of the bridge circuit is obtained by the double random SVPWM control method, the power switch transistor is controlled, and the reactive power and the negative sequence current component are compensated. So that that structure of the invention is clear, not only can the reactive current component and the negative sequence current componentcaused by load unbalance be compensated accurately, At that same time, the harmonic characteristic of SVG power bridge circuit is consider, and the harmonic peak of output current and line voltage issuppressed by using the double random SVPWM modulation method, which can reduce the harmonic pollution of SVG to the power system when the SVG is in grid-connected operation.

The invention discloses a novel broadband high-voltage cascaded linear amplifier device. N linear amplifier modules are cascaded, and an independent direct-current power supply module is arranged in each linear amplifier module to supply power to the linear amplifier module, so that an input voltage signal can be amplified by N times, and high voltage can be output. Meanwhile, the linear optical coupling circuit is adopted to carry out signal transmission on the linear amplifier circuit, alternating current signals can be isolated, the insulation and anti-interference effects are achieved, cross-over distortion is greatly reduced, the waveform distortion rate is reduced, and meanwhile good linearity can be achieved through the linear amplifier circuit.

The invention discloses a novel axial coreless motor rotor structure and a heat dissipation method thereof. The structure comprises a plurality of permanent magnets annularly distributed on back iron along the radial direction, an air gap is arranged between two adjacent permanent magnets, a U-shaped iron pole is inserted in the air gap between every two adjacent permanent magnets, and air slots formed by the U-shaped parts of all the U-shaped iron poles face the back iron. The U-shaped iron poles are filled between every two adjacent permanent magnets in the rotor disc of the motor to improve the air gap flux density waveform of the axial coreless motor, so that the distortion rate of the air gap flux density waveform of the motor is reduced, the waveform of counter electromotive force of the motor is also improved, and the distortion rate is reduced. Meanwhile, the composite phase-change material is filled in the air slots added with the U-shaped iron poles, so heat generated by the motor rotor can be absorbed, the temperature of the motor rotor is reduced, and the demagnetization risk of the permanent magnets is reduced.

The invention discloses a stator and rotor structure of a surface-mounted permanent magnet motor, which comprises a stator, a rotor, stator water holes, permanent magnets and permanent magnet auxiliary grooves. In order to output high torque and stably operate the motor, the structure adopts an inner rotor and outer stator mechanism, the inner rotor adopts a magnetic pole surface-mounted type, and the magnetic pole adopts two non-uniform permanent magnets, the inner side arc and the outer side arc are located on the same circle with the proportion of 6:5, auxiliary grooves are formed in magnetic poles, excitation windings are placed in inner stator winding grooves, and two round holes are formed in stator teeth to be connected with water pipes to facilitate heat dissipation of the motor. According to the invention, the asymmetric structure of the magnetic poles is used to reduce eddy current loss and optimize the air-gap flux density waveform, reduce magnetic leakage and enhance the sinusoidal property of the air-gap magnetic field; the permanent magnets are used for forming auxiliary slots to reduce cogging torque pulsation; and the purposes of reducing the waveform irregularity and controlling the temperature rise are achieved by using the water holes formed in the stator, so that the motor can operate more safely and stably.

The present invention is one RE permanent magnetic generator with permanent magnet rotor and consists of stator and rotor. The stator includes iron core, single-layer winding and seat; and the rotor has even number of tile-shaped magnet poles of RE permanent magnetic material distributed homogeneously. The stator winding has several subsidiary windings, each of which is connected serially to the main winding of each pole. The generator of the present invention has the advantages of both single-layer winding and double-layer winding and has output voltage waveform deformation rate lower than 2 % and voltage regulating rate lower than 3 %.

The invention discloses a waveform control system, comprising a Miller integrating circuit, a Schmidt circuit, a Schmidt trigger and a power supply VCC, wherein the output end of the Miller integrating circuit is connected with the Schmidt circuit, the output end of the Schmidt circuit is separately connected with the input end of the Schmidt trigger and the input end of a filter circuit, the output end of the Schmidt trigger is connected with the input end of the Miller integrating circuit, the power supply VCC separately supplies power to the Miller integrating circuit and the Schmidt trigger, and the output end of the filter circuit is connected with the output end Vo of the system. According to the waveform control system disclosed by the invention, a direct current power supply VCC is directly converted to a square wave signal, the amplitude value and frequency of the square wave signal at the output end can be changed by changing the size of the power supply VCC and the charge and discharge frequency of a capacitor C1, the secondary amplification is not required, high stability can be achieved, and the obtained waveform is low in distortion rate.