95 results about "Harmonic phase" patented technology

The present invention relates to a method of measuring motion of an object such as a heart by magnetic resonance imaging. A pulse sequence is applied to spatially modulate a region of interest of the object and at least one first spectral peak is acquired from the Fourier domain of the spatially modulated object. The inverse Fourier transform information of the acquired first spectral-peaks is computed and a computed first harmonic phase image is determined from each spectral peak. The process is repeated to create a second harmonic phase image from each second spectral peak and the strain is determined from the first and second harmonic phase images. In a preferred embodiment, the method is employed to determine strain within the myocardium and to determine change in position of a point at two different times which may result in an increased distance or reduced distance. The method may be employed to determine the path of motion of a point through a sequence of tag images depicting movement of the heart. The method may be employed to determine circumferential strain and radial strain.

The present invention provides a method, system, and apparatus to monitor cardiovascular signals such as arterial blood pressure (ABP), pulse oximetry (POX), and intracranial pressure (ICP). The system can be used to calculate and monitor useful clinical information such as heart rate, respiratory rate, pulse pressure variation (PPV), harmonic phases, pulse morphology, and for artifact removal. The method uses a statistical state-space model of cardiovascular signals and a generalized Kalman filter (EKF) to simultaneously estimate and track the cardiovascular parameters of interest such as the cardiac fundamental frequency and higher harmonics, respiratory fundamental frequency and higher harmonics, cardiac component harmonic amplitudes and phases, respiratory component harmonic amplitudes and phases, and PPV.

The invention discloses a high-precision harmonic parameter estimation method based on a composite iterative algorithm. The method comprises the steps as follows: firstly, a harmonic amplitude value is directly calculated by utilizing a three-peak interpolation algorithm, and meanwhile, a harmonic phase is calculated to serve as an initial phase value for composite iteration, then the initial phase value is transmitted to a phase difference correction algorithm to obtain a frequency deviation value by utilizing the phase difference correction algorithm, and the phase difference correction algorithm is combined with a spectral leakage cancellation algorithm so as to obtain a phase value for the first-time iterative computation; circulating iteration is performed between the phase difference correction algorithm and the spectral leakage cancellation algorithm repeatedly until a phase iteration result meeting the error limit requirement is obtained. According to the invention, with the adoption of the three-peak interpolation algorithm, the estimation precision of the harmonic amplitude value is improved, and the phase obtained by utilizing the three-peak interpolation algorithm serves as an initial value, and the phase difference correction algorithm and the spectral leakage cancellation algorithm are combined to construct the composite iterative algorithm, so that the estimation precision of a harmonic phase and frequency is greatly improved.

The invention discloses a ground fault current compensation system and method for a self-produced power supply phase power supply. The system comprises a phase power supply generator, a phase power supply phase compensator, a fling-cut switch, a controller and a voltage transformation device. An output end of a phase compensator of a power supply is connected to a system neutral point through thefling-cut switch. The system can passively generate power distribution network power supply phase power supply and harmonic phase power supply and input anti-phase power supply phase power supply andthe harmonic phase power supply into the system according to fault logic. The complete compensation of power distribution network grounding fault reactive current, harmonic current and active currentis achieved, the defect that compensation is incomplete by adopting a power electronic device inversion injection method after electricity is taken from a bus system is overcome, and the problems thatan active inversion method has a poor metallic grounding compensation effect and a traditional arc suppression coil cannot achieve full compensation are solved. The system is efficient and accurate and can completely compensate overvoltage and overcurrent generated by a grounding fault, the safety of a power grid and equipment is guaranteed, and the risk of electric shock of a human body is completely avoided.

According to one exemplary embodiment, a switching module includes a first harmonic phase tuning filter coupled to a first input of an RF switch. The first harmonic phase tuning filter is configured to provide an output impedance that substantially matches an input impedance of the RF switch at approximately a fundamental frequency and to provide a high impedance at approximately a harmonic frequency generated by the RF switch. The first harmonic phase tuning filter includes an LC circuit coupled between input and output terminals of the first harmonic phase tuning filter and tuned to provide the high impedance at approximately the harmonic frequency generated by the RF switch. The RF switching module further includes a second harmonic phase tuning filter coupled to a second input of the RF switch. The first and second harmonic phase tuning filters can be fabricated on a single semiconductor die.

The invention discloses a grounding fault current compensation system and method for a self-generated power supply phase power supply. The grounding fault current compensation system comprises a phasepower supply converter, a fling-cut switch, a voltage transformation device and a controller, wherein the input end of the phase power supply converter is connected with a bus, the output end of thephase power supply converter is connected with the input end of the fling-cut switch, the voltage transformation device is connected between the phase power supply converter and a system neutral pointin series, the controller is connected with a voltage transformer of the bus, and the output end of the controller is connected with the input end of the fling-cut switch. The system can passively generate a power distribution network power supply phase power supply and a harmonic phase power supply, and the reversed-phase power supply phase power supply and the harmonic phase power supply are put into the system according to fault logic, so that complete compensation of reactive current and harmonic current of the grounding fault of the power distribution network is achieved, the defect thatthe compensation is incomplete by adopting a power electronic device inversion injection method after electricity is taken from a bus system is overcome, and the problems that an active inversion method is poor in metallic grounding compensation effect and a traditional arc suppression coil cannot achieve full compensation are solved.

The invention discloses a compressor high-frequency harmonic torque compensation method, a compressor controller and an air conditioner. The method comprises the steps of acquiring a vibration amplitude of the compressor in operation; when the vibration amplitude of the compressor is higher than a first preset vibration value, acquiring a load torque harmonic wave and an output electromagnetic torque harmonic wave of the compressor in the current operation working condition, determining a harmonic compensation order according to the load torque harmonic wave and the output electromagnetic torque harmonic wave; determining a harmonic frequency which corresponds with the harmonic compensation order, stacking a sine electromagnetic torque with a corresponding frequency into an output electromagnetic torque according to the harmonic frequency, adjusting a harmonic phase which corresponds with the sine electromagnetic torque according to a multiple-iteration method; and when a fact that the harmonic amplitude which corresponds with the output electromagnetic torque with the stacked sine electromagnetic torque reaches a highest value, recording the harmonic wave which corresponds with the current sine electromagnetic torque as an optimal compensation phase, and performing compensation on the high-frequency harmonic torque of the compressor according to an optimal compensation phase. The compressor high-frequency harmonic torque compensation method, the compressor controller and the air conditioner realize high-frequency harmonic torque compensation of the compressor.

The invention provides a frequency tracking method for an electric automobile wireless charging system and relates to the field of wireless charging. According to the frequency tracking method, the problem that the charging efficiency of an existing electric automobile wireless charging system is low at the time of charging due to external disturbance is mainly solved. The system comprises a high-frequency inverting circuit, an LC resonance circuit and a frequency tracking circuit. The high-frequency inverting circuit is used for producing a high-frequency signal consistent with the LC resonance circuit in frequency to enable the whole system to resonate. The frequency tracking circuit is used for detecting the voltage and current phase of a wireless transmitting terminal and outputting a PWM driving signal to the high-frequency inverting circuit after a series of adjustments. The LC resonance circuit is used for constituting a resonance system and guaranteeing efficient energy transmitting. The method comprises the steps that voltage and current signals are collected to conduct FFT transformation to obtain a phase difference; the phase difference is subjected to PI operation through phase locking treatment to obtain an adjusted frequency; and the adjusted frequency serving as the frequency of the PWM driving signal of the high-frequency inverting circuit produces a high-frequency current to form the resonance system to transmit energy. The resonance frequency of the system is tracked through the method of a resonance-type phase-locked loop of a voltage and current fundamental harmonic phase, and it can be effectively ensured that the system keeps the resonance state and has high charging efficiency.

The invention discloses a method for measuring common-frequency periodic signal phase differences. The method includes the steps of S1, carrying out synchronous sampling on W sample data of two common-frequency periodic signals to be measured in an evenly-spaced mode, S2, obtaining harmonic amplitude values A1k and A2k and harmonic phase angles of ml subharmonic and m2 subharmonic of the two common-frequency periodic signals to be measured, S3 computing initial phase angles of the two common-frequency periodic signals to be measured according to the harmonic amplitude values A1k and A2k and the harmonic phase angles, and S4, computing the phase differences according to the difference of the two initial phase angles and obtaining high-accuracy phase different measurement results. Thus, quality of instrument devices in the fields like electrical equipment condition monitoring, signal collecting and analysis, communication and automatic control can be achieved, wherein the instrument devices are based on the phase difference technology.

According to one exemplary embodiment, a switching module includes a first harmonic phase tuning filter coupled to a first input of an RF switch. The first harmonic phase tuning filter is configured to provide an output impedance that substantially matches an input impedance of the RF switch at approximately a fundamental frequency and to provide a low impedance at approximately a harmonic frequency generated by the RF switch. The first harmonic phase tuning filter includes an LC circuit coupled between an output terminal of the first harmonic phase tuning filter and a ground and tuned to provide the low impedance at approximately the harmonic frequency generated by the RF switch. The RF switching module further includes a second harmonic phase tuning filter coupled to a second input of the RF switch. The first and second harmonic phase tuning filters can be fabricated on a single semiconductor die.

A calibration procedure for a real-time load-pull system whereby the signal passes through at least one of the tuners of said real-time load-pull system. A calibration standard is connected to the test ports and an electromagnetic wave signal passes through one of the tuners before passing through the wave sensing structure. After having passed the wave sensing structure the electromagnetic wave signal interacts with the calibration element. This results in a reflected and eventually a transmitted electromagnetic wave signal that pass through the wave sensing structures of the system. The sensed electromagnetic wave signals are measured by means of a receiver. The procedure is repeated with different calibration standards. Then a line element is connected to the test ports and, one after the other, a set of calibration standards, a power meter and a harmonic phase reference generator are connected to the output tuner, each time sending a signal and measuring the wave signals. The measured data is used to calculate the error coefficients of the real-time load-pull system.

The invention relates to a digital signal processing method. The method solves the problem of unable to obtain the accurate wideband harmonic phase by using the existed technique. Based on the NTN correct technique, this invention obtains a serious wideband impulses, corrects orderly their time base aberration, uses average signal shift to eliminate co-modulate interference, corrects mismatch aberration, and signal dithering. Then phase-spreading and eliminating linearization against the obtained phase frequency response function obtains the harmonic phase. Finally, the phase uncertainty can be obtained by means of introducing the error spread formulation and assumption verification estimation in the complex frequency area. The wideband phase obtained by this invention can be used in the phase correction in large-signal network analyzer and hi-speed sampling oscilloscope.

A fiber amplifier system including at least one seed source providing an optical seed beam and a harmonic driver providing a sinusoidal drive signal at a predetermined frequency. The system also includes a harmonic phase modulator that receives the seed beam and the drive signal, where the harmonic phase modulator frequency modulates the seed beam using the drive signal so as to remove optical power from a zeroth-order frequency of the seed beam and create sidebands separated by the frequency of the drive signal. A dispersion element receives the frequency modulated seed beam and provides temporal amplitude modulation to the seed beam and a nonlinear fiber amplifier receives the amplitude modulated seed beam from the dispersion element and amplifies the seed beam, where the dispersion element and the fiber amplifier combine to remove optical power from the sidebands and put optical power back into the zeroth-order frequency.

The invention discloses a harmonic phase locking frequency source which comprises a crystal oscillator, a microwave sampling phase discriminator, a loop filter and automatic capture circuit, a voltage-controlled oscillator, a coupler and a locking detection circuit. The invention also provides a phase locking method of the harmonic phase locking frequency source. The frequency source provided by the invention has the characteristics of low phase noise, better clutter suppression characteristic and the like.

The invention provides a wind farm harmonic evaluation prediction method. The method includes the following steps that: a mathematical model is established for individual wind turbine generator sets in a wind farm to be established, and the overall distribution condition of harmonic current of various orders which is outputted by the individual wind turbine generator sets under historical wind speed at a corresponding region can be obtained through utilizing the mathematical model, and a corresponding probability density function can be obtained through utilizing the least square fit; the historical data of harmonic current of an existing wind farm are put into statists, so that the overall distribution interval of harmonic phases of various orders or the discrete degree of the harmonic phases of various orders can be obtained, and therefore, a random model of the phases is established; and the amplitude and phase conditions of the harmonic current of the sets in the wind farm can be simulated according to the random model; amplitude and phase variation values of harmonic current brought by power transmission lines and transformers thereof are calculated according to a wind farm topologic structure diagram and a power transmission line and transformer harmonic model, so that the magnitude and phase angle of the harmonic current of various orders brought by the sets can be obtained, wherein the harmonic current is harmonic current which has not been aggregated to a main transformer; and harmonic phase superposition based on sector distribution is evaluated.

The invention discloses an inter-harmonic detection system of a three-phase active power distribution network. The inter-harmonic detection system comprises a three-phase current testing module, a module for transforming three-phase static coordinates to two-phase static coordinates, an inter-harmonic phase-locked loop circuit to be determined, a module for transforming the two-phase static coordinates to two-phase synchronous inter-harmonic frequency rotating coordinates to be determined, a low pass filter, a module for transforming the two-phase synchronous inter-harmonic frequency rotating coordinates to be determined to the two-phase static coordinates, and a module for transforming the two-phase static coordinates to three-phase static coordinates. The inter-harmonic detection system, provided by the invention, is very effective on the inter-harmonic voltage and the inter-harmonic current of a power distribution system. The invention is a system with simple structure, clear conception, and simpler dynamic and static inter-harmonic detection and inter-harmonic cancellation.

The invention provides a method for eliminating harmonic interference. The comprises the steps of determining a harmonic shifting amount which is a difference between a harmonic interference frequency point and a central frequency point of a receiving signal; determining the harmonic amplitude and the harmonic phase of a harmonic interference signal included in the receiving signal according to the receiving signal and the harmonic shifting amount; determining the harmonic interference signal according to the harmonic amplitude and the harmonic phase; and subtracting the harmonic interference signal from the receiving signal, thus eliminating the harmonic interference signal in the receiving signal. Therefore, according to the method provided by the invention, interference to the receiving signal caused by the harmonic signal is effectively solved, and the sensitivity performance of a receiver is improved, so that the performance of the receiver is not influenced by the strength of the harmonic signal, and the receiver has high robustness.

The invention discloses a grounding fault current compensation system and method for a self-produced power supply phase power supply. The system comprises a phase supply power converter, an on-off switch, a voltage regulator and a controller. The input end of the phase power supply converter is connected with a bus, and the output end is connected with the input end of the on-off switch. The common connection point of the on-off switch and the system neutral point are connected on the non-homonymous ends on the two sides of the voltage regulator, and the remaining connection points of the voltage regulator are grounded. The controller is connected with the voltage transformer of the bus. The output end of the controller is connected with the input end of the on-off switch and the voltage regulator. The system can passively generate the power supply phase power supply and the harmonic phase power supply of a distribution network and put the reverse phase power supply and the harmonic phase power supply into the system according to the fault logic so as to realize complete compensation of reactive current, harmonic current and active current of the distribution network grounding fault and solve the problems of poor metal grounding compensation effect of the active inverter method and inability of complete compensation of the traditional arc suppression coil.

The invention discloses a power grid harmonic testing and analysis method comprising the steps of: obtaining a wave recording data file of a wave recording device of a testing point according to preset wave recording device parameters, wherein the wave recording data file comprises channel data of three-phase alternating current voltage and three-phase alternating current of the testing point; selecting sampling data of ten-cycle wave length as an analysis unit according to a predetermined channel and performing a fast Fourier transformation on the sampling data to obtain fundamental wave, each sub-harmonic effective value and each sub-harmonic phase of the predetermined channel; obtaining each sub-harmonic voltage distortion rate, total harmonic distortion rate and each sub-harmonic current effective value according to the fundamental wave and each sub-harmonic effective value, so as to obtain a harmonic content level of the testing point; obtaining corresponding phase difference by each sub-harmonic current phase in each sub-harmonic phase minus each sub-harmonic voltage phase; and obtaining the transmission direction of the corresponding harmonic according to the phase difference and the corresponding harmonic effective power. According to the method, device, apparatus and medium for power grid harmonic testing and analysis, the power grid harmonic testing efficiency can beimproved, the harmonic source searching can be completed and the measurement data quality and the result accuracy are improved.

The invention relates to a method for assessing occurrence of commutation failure based on the harmonic comprehensive commutation coefficient. The corresponding AC bus voltage of a certain extinctionangle drop moment of operation to the inverter station converter valve is acquired, and the phase offset of the voltage amplitude of each harmonic and the fundamental phase relative to the normal commutation situation and the corresponding leading trigger angle and the extinction angle of the moment under normal operation of the system are obtained after Fourier transform of the AC bus voltage ofthe moment; the harmonic voltage comprehensive influence factor and the harmonic phase comprehensive influence factor are calculated, the two factors are added to obtain the harmonic comprehensive commutation coefficient, and the DC system commutation failure is judged according to the situation of whether the harmonic comprehensive commutation coefficient is greater than the maximum commutation area margin. The calculation method is low in calculation dimension and fast in speed; the method comprehensively considers the harmonic order, the harmonic voltage amplitude and the fundamental offsetcaused by the harmonic waves so that the calculation and judgment result is enabled to be more accurate; and the method is suitable for evaluation of continuous commutation failure.

The invention discloses a ground fault current compensation system and method for a self-produced phase power supply, The ground fault current compensation system includes a phase power supply generator, a phase power supply phase compensator, a switch, a controller, and a voltage regulator. The input end of the phase power supply generator is connected to a bus. The output end of the phase powersupply generator is connected to the input end of the phase power supply phase compensator. The voltage regulator is connected in series between the phase power supply phase compensator and the neutral point of the system. The controller is connected to the voltage transformer of the bus. The output end of the controller is connected to the switch. The system passively generates the phase power supply, and puts the inverted power supply phase and the harmonic phase power supply into the system according to the fault logic. The ground fault current compensation system achieves the complete compensation of the reactive current, the harmonic current and the active current of the ground fault of a distribution network, and solves the problems that the power electronic device inversion injection method cannot achieve full compensation and is complex to control after taking power from the system.

The invention discloses a variational Bayesian parameter learning method based harmonic current detection algorithm for an electric vehicle charging station. The algorithm includes establishing a charger equivalent circuit model, and judging whether a charging pile can be randomly accessed into a power distribution network system by utilizing a random number algorithm and a comparison module; performing ideal superposition calculation on the harmonic current meeting gaussian normal distribution so that an ideal harmonic superposition coefficient calculation method can be obtained; and performing sampling on harmonic phase to form two sets of random set of state space and measurement space, obtaining model parameters through the lower bound of a logarithmic edge likelihood function by usinga variational Bayesian parameter learning method, continuously maximizing the lower bound of the likelihood function, and iteratively updating variational phase parameters until approximate distribution approaches the true posterior distribution of the parameters so that harmonic phase superposition detection can be realized. Actual harmonic superposition coefficients can be obtained by substituting harmonic phase distribution into the harmonic superposition coefficient calculation method, so that accurate detection of multi-harmonic current superposition at same time in a charging station can be realized.

The invention provides a three-phase high-precision harmonic electric energy meter which comprises a frequency measurement module, a sampling control module, an amplitude and phase calculating module,a harmonic phase compensation module and a harmonic electric energy accumulation module connected successively. The electric energy meter has the advantages that 1) hardware frequency measurement iscombined with software frequency measurement, software and hardware filtering measures are used to eliminate interference of higher harmonic waves in frequency measurement, and full-period sampling isensured in the source; 2) the M2 sampling control module uses a PWM+DMA automatic control manner, the sampling process needs no intervention of a CPU, and the data processing efficiency and reliability in the high sampling rate are ensured; 3) the M3 amplitude and phase calculating module uses a prime factor and subgroup algorithm to reduce influence caused by frequency fluctuation and harmonic amplitude fluctuation, and improve the consistence; and 4) the M4 harmonic phase compensation module compensates the phase angle of each harmonic power accurately to realize high-precision harmonic power measurement. Thus, the high-precision harmonic electric energy is accumulated.