69 results about "Harmonic load" patented technology

In a power amplifier a Doherty amplifier is provided with an output higher harmonic reflection circuit that is connected to the output terminal of a first FET chip and sets an even-numbered higher harmonic load of an output signal at the output terminal to be a short-circuit, or at a low impedance approximating a short-circuit, and sets an odd-numbered higher harmonic load of an output signal at the output terminal to be an open-circuit, or a high impedance approximating an open-circuit.

In a power amplifier a Doherty amplifier is provided with an output higher harmonic reflection circuit that is connected to the output terminal of a first FET chip and sets an even-numbered higher harmonic load of an output signal at the output terminal to be a short-circuit, or at a low impedance approximating a short-circuit, and sets an odd-numbered higher harmonic load of an output signal at the output terminal to be an open-circuit, or a high impedance approximating an open-circuit.

An automatic, frequency selective microwave tuner, used for load pull transistor testing, is capable of generating independently controllable reflection factors, both in amplitude and phase, at several, harmonic or not, frequencies simultaneously. The tuner employs horizontally and vertically adjustable high Q resonant probes and replaces, when used in harmonic load pull set-ups, otherwise required combinations of wide-band tuners with harmonic rejection tuners or wide-band tuners and frequency discriminators (diplexers or triplexers).

A method of controlling a helicopter having a rotor with blades is provided. The method includes receiving, by a computing device comprising a processor, at least one input associated with the helicopter; generating, by the computing device, control signals configured to counteract blade bending associated with the rotors based on the received at least one input; measuring, by the computing device, blade signals using sensors for the blades; extracting, by the computing device, harmonic loads from the measured blade signals; adapting, by the computing device, the control signals based on the harmonic loads; and controlling, by the computing device, servos connected to the blades to adjust the blades according to the adapted control signals to reduce vibratory loads on the blades.

The present invention discloses a sparse representation method for dynamic load identification of a mechanical structure for solving ill-posed natures of the dynamic load identification inverse problem and overcoming the disadvantage that the number of primary functions is required to be determined in advance by a current function approximation method. The sparse representation method comprises the following steps of (1) measuring a frequency response function between an action point of dynamic load of the mechanical structure and a response point of the mechanical structure by using a hammering method, and obtaining a transfer matrix through processing; (2) measuring a response signal generated by the dynamic load acting on the mechanical structure; (3) selecting primary functions to construct a sparse representation dictionary according to morphology of the dynamic load; (4) constructing an L1-norm-based sparse representation model of the dynamic load identification; (5) solving the sparse representation model of the dynamic load identification, and obtaining dynamic load sparse representation coefficient vectors; and (6) obtaining the identified dynamic load. Impact and harmonic load acting on the mechanical structure can be effectively identified, and compared with a traditional Tikhonov regularization method based on L2 norm, the sparse representation method has the advantages that identification precision is high and stability is high.

A method and test setup for reducing the RF power requirement in active load pull uses impedance tuners between the output of the test transistor and the active RF power injection network. The active network uses either a closed loop (active load) configuration or an open loop network employing split or synchronized signal sources. The impedance tuners are wideband (fundamental) tuners, harmonic rejection tuners or multi-harmonic tuners. A 7:1 transforming ratio of the tuners represents the best compromise between power matching and tuner loss, yielding a reduction of 11dB in power requirements from the active load or the synchronized source(s); if only the fundamental signal is injected at the output of the DUT, a multi-harmonic tuner or a harmonic rejection tuner is used for independent harmonic tuning; if multiple harmonic signals are injected, a multi-harmonic tuner is used and creates passive harmonic loads while reducing at the same time the power requirements from the harmonic injection sources.

An electro-mechanical harmonic load pull tuner uses three variable and adjustable shunt air capacitors and three variable and adjustable series phase shifters and creates independently controllable impedances at three harmonic frequencies in the frequency range between 30 and 250 MHz. Independent harmonic tuning is possible because the combination of adjustable shunt capacitors and series phase shifters allows generating more than 1019 impedance states at each frequency covering the entire Smith chart; appropriate impedance-search Error Function-based optimization algorithms allow fast harmonic tuning for impedance tuning and matching the output of RF transistors and amplifiers at the fundamental and harmonic frequencies. Stepper motors, drivers and control software are used to automate, calibrate and use the harmonic tuner in an automated harmonic load pull measuring setup.

The invention provides an improved particle swarm algorithm-based optimized configuration method of a distributed electrical connection power distribution system. The optimized configuration method comprises the following steps: 1, inputting optimized configuration calculation parameter data, initializing particles and the flying speed of a particle swarm and a connected distributed power factor; 2, selecting an optimized configured type, selecting an entrance according to distributed power optimized configuration scheme types, namely addressing tolerance, sizing location optimization and location optimization and tolerance with a specified access number N; 3, selecting an optimization configuration goal and recording power distribution system parameters and distributed power system parameters, wherein the parameters includ system grid loss and average voltage level parameters; 4, performing optimized configuration calculation, performing fundamental wave load flow calculation and harmonic load flow calculation under each particle to obtain the system node voltage, the system fundamental wave loss and the harmonic loss under the particle, and then calculating a system node deviation index and a system total loss index; and 5, checking and outputting the result of the optimized configuration calculation.

The invention relates to a reconfigurable radio frequency and microwave power amplifier. The reconfigurable radio frequency and microwave power amplifier comprises an input radio frequency switch, anadjustable input matching network, a power amplifier stage, an adjustable output matching network and an output radio frequency switch which are connected in turn, and an adjustable harmonic impedancecontrol network and a bias and control circuit; and the adjustable input matching network and the adjustable output matching network respectively comprise at least one LC network with a fundamental wave impedance conversion function, wherein the LC network comprises at least one reconfigurable device, and the reconfigurable device is connected with a passive device in the LC network in parallel.According to the reconfigurable radio frequency and microwave power amplifier provided by the invention, the reconfigurable harmonic impedance control network and the fundamental wave impedance matching network are realized through the adjustable input matching network, the adjustable harmonic impedance control network and the adjustable output matching network; and when a power amplifier works indifferent bands of a linear power amplifier mode, a load impedance network can be reconfigured in real time, which satisfies the fundamental wave impedance and harmonic load required by each frequency band.

The invention aims to provide a system for monitoring the state of a harmonic load. The system is realized by a following method as follows: an everyday sample is established according to statistic characteristic quantity of historical data corresponding to the effective value of every-order harmonic current; a population sample in any time period is established according to the everyday sample; a normal cloud model of the effective value of the every-order harmonic current is established and converted to the boundary membership under a standard normal cloud model according to the statistic rule of the population sample, so as to establish a retrieval body of the harmonic current. By the system, the state of the harmonic load can be diagnosed and minored in real time according to the retrieval body of the harmonic current; the system is applicable to the occasion when the running state is abnormally small; and the method has a certain practical value in engineering.

The invention discloses a multifunctional comprehensive tester for testing mechanical characteristics of deformation of pavements and decks, which belongs to the test equipment of mechanical properties. The multifunctional comprehensive tester mainly comprises a supporting stand, a controllable temperature area, a vertical loading system, a vertical load boundary balancing system, a mechanical crank connecting rod circulatory loading system, a loading displacement sensor and an integrated control display system. The time variations of loading and deforming are recorded after the test begins. The multifunctional comprehensive tester can partially load indentation tests and partially load creep tests, and can do partial cyclic loading test through utilizing the vehicle load which is generated by the mechanical crank connecting rod circulatory loading system and is simulated and repeatedly acted by harmonic load. The multifunctional comprehensive tester can finish multinomial system tests without changing a cramping apparatus, can fully obtain the relative dynamic-static mechanical properties of pavements and decks, anti deformation capacity index and important parameter C, phi of anti-shearing property of material, and can solve the problem that a deformation stability integrated test and comprehensive evaluation can not be done on engineering sites.

The invention discloses a method and system for detecting the state of a power distribution transformer under harmonic load influence. The method includes the following steps that: the noise signals of the power distribution transformer are detected; a noise signal characteristic parameter and a sound pressure level are extracted; and the noise signal characteristic parameter is compared with a preset noise signal characteristic parameter threshold value, if the noise signal characteristic parameter is higher than the preset noise signal characteristic parameter threshold value, it is judged that the power distribution transformer is in a harmonic load operating state, and the sound pressure level is compared with a preset sound pressure level early warning threshold value, if the sound pressure level exceeds the preset sound pressure level early warning threshold value, it is judged that the operation of the power distribution transformer is abnormal, otherwise, it is judged that the operation of the power distribution transformer is normal. The system comprises a noise signal detection program unit, a noise characteristic extraction program unit and a state detection program unit. According to the method and system of the invention, contact with electrified equipment is not required, so that the safety of detection is high; workers are not required to go to a site to carry out detection and analysis; and therefore, the method and system of the invention have the advantages of time-saving and labor-saving performance, high safety, high efficiency and convenient detection.

The present invention provides a distribution network unbalanced harmonic load index prediction method. The method comprises: establishing a time sequence of a distribution network unbalanced harmonic load index evolutionary system, processing measured data of the time sequence by a nonlinear simplex method, and performing reflection operation on a vertex target function value so as to perform prediction calculation of a distribution network unbalanced harmonic load index and obtain a prediction value of the distribution network unbalanced harmonic load index. According to the method provided by the present invention, the prediction calculation can be performed on the distribution network unbalanced harmonic load index according to monitored parameters, a harmonic level can be controlled in real time according to a calculation result; the harmonic unbalance phenomenon can be effectively avoided; and reliability and economy of a distribution network system can be significantly improved.

The invention provides a control method for actively suppressing power grid harmonics. A harmonic component can be precisely detected and separated by adopting a harmonic current detection method based on transient reactive power; in order to achieve a better output current control effect than the conventional proportion and integration (PI) control effect, a composite control strategy, in which fuzzy PI closed loop adjustment is taken as a core, is determined; therefore, online adjustment and optimization of PI parameters are realized; and the harmonics of a harmonic load and a device to a power grid are suppressed effectively.

The invention discloses a method for estimating probabilistic load flow of a harmonic pollution user, which can more accurately implement operation estimation or pre-estimation on injection pollution of a harmonic interference user. The method has the most obvious advantage that probabilistic harmonic load flow calculation is carried out by adopting user fundamental power probability distribution and harmonic characteristic probability distribution parameters so as to obtain probability distribution characteristics of harmonic pollution of the user for a power grid, not just obtain a harmonic pollution result under a certain specific operating working condition, and the conclusion is more comprehensive and more reasonable.

A harmonic load pull system uses a number of synchronized signal sources to inject harmonic power into the output of a power transistor. The mismatch between the signal sources and the transistor internal impedance is reduced by using multi-harmonic tuners, which pre-match the impedance of the signal sources to the internal impedance of the transistor at each harmonic frequency independently. Actual tuning is electronic by changing the amplitude and phase of the injected signals. The transmitted and reflected waves are measured and optimized through bi-directional couplers connected between the transistor and the tuner and a wideband harmonic receiver.

A high frequency power amplifier that can improve an efficiency of an operation of a transistor without limiting any input-side higher harmonic load of an impedance matching circuit to a short-circuit load, and can increase a quantity of reflection of higher harmonics. By adjusting line lengths L1 to L5 and line widths W1 to W5 of the signal lines 1 to 5, a 2nd higher harmonic can be adjusted to be an open load (a reflected phase angle of Γin: 0-90°, the quantity of reflection: 0.6-1.0), and a 3rd higher harmonic is adjusted to be a short-circuit load (the reflected phase angle of Γin:110-270°, the quantity of reflection: 0.6-1.0). By this optimization of an input-side higher harmonic load of the impedance matching circuit, an efficiency of transistor operation can be improved. By disposing a higher harmonic processing circuit 12 of higher orders closer to a transistor 1, there is provided a high frequency power amplifier with a shortened line length between the higher harmonic processing circuit 12 and the transistor 1, and increased quantity of reflection of higher harmonics.

The invention discloses an active power filter device for specific sub-harmonics. The device is applicable to a circuit comprising a system power supply and a harmonic load, and comprises a transformer, an inverter and a modulation signal generation module; the primary winding of the transformer is connected in series with the harmonic load, and connected to a circuit formed by the system power supply and the harmonic load; the modulation signal generation module is used for generating modulation signals for the inverter, and the modulation signals are generated by superposing primary fundamental wave current amplified reversely and primary specific n sub-harmonic current amplified positively; the inverter is used for converting direct current signals into alternating current signals having the same frequency as the modulation signals and injecting the alternating current signals into the secondary winding of the transformer, so that the primary fundamental wave equivalent impedance of the transformer is Z1+(1-a)Zm, and the primary n sub-harmonic equivalent impedance of the transformer is nZ1+(1+beta)nZm. Based on fundamental wave and specific sub-harmonic flux hybrid control, the primary side of the transformer is short-circuited relative to fundamental waves and open-circuited relative to specific sub-harmonics.

A method and test setup for reducing the RF power requirement m active load pull uses impedance tuners between the output of the test transistor and the active RF power injection network. The active network uses either a closed loop (active load) configuration or an open loop network employing split or synchronized signal sources. The impedance tuners are wideband (fundamental) tuners, harmonic rejection tuners or multi-harmonic tuners. A 7:1 transforming ratio of the tuners represents the best compromise between power matching and tuner loss, yielding a reduction of 11 dB in power requirements from the active load or the synchronized source(s); if only the fundamental signal is injected at the output of the DUT, a multi-harmonic tuner or a harmonic rejection tuner is used for independent harmonic tuning; if multiple harmonic signals are injected, a multi-harmonic tuner is used and creates passive harmonic loads while reducing at the same time the power requirements from the harmonic injection sources.

The invention discloses a wear tester for electric power fittings, comprising a frame and a load carrier arranged on the frame; the upper end of the load carrier is connected with a first hanging rope which runs through a pulley set hung at the top of the frame and is then connected with an upper hanging device, a lower hanging device corresponds to the upper hanging device, the lower hanging device is connected with a rocking device, the rocking device is also connected with a power unit, the load carrier comprises a spring mechanism, a winding mechanism and a vibration exciter, the upper end of the spring mechanism is connected with the other end of the first hanging rope, the lower end of the spring mechanism is connected with the winding mechanism, the vibration exciter is also arranged on the spring mechanism, and the vibration exciter applies dynamic load to the spring mechanism. The loader carrier that considers both dead load and simple harmonic load is used provided to simulate load of an electric power fitting in actual engineering application, such that wear results of the tester are more precise and more practical.

The invention discloses an experiment system and method for a unified electric energy quality controller. The system includes a controllable voltage generating unit for generating dynamically adjustable voltage, a harmonic load unit used for generating current harmonic and providing a nonlinear load, a reactive power test accompanying unit use for generating reactive power, a bypass circuit breaker, a first circuit breaker and a second circuit breaker; one end of the controllable voltage generating unit is connected in parallel with the bypass circuit breaker, and thereafter is connected into power grid voltage, and the other end of the controllable voltage generating unit is connected with the series side of a UPQC; the harmonic load unit is connected with the parallel side of the UPQC through the first circuit breaker; and the reactive power test accompanying unit is connected with the parallel side of the UPQC through the second circuit breaker. According to the method, the above system is utilized to realize voltage compensation and harmonic suppression experiments and reactive power compensation experiments. With the method adopted, various kinds of function experimental confirmation of the unified electric energy quality controller can be realized based on one such experiment system. The experiment system and method have the advantages of simple structure principles, easy and convenient operation and excellent experimental performance.

The invention provides a method for minimized the harmonic load of a welding power supply and a welding power supply for executing the method. According to the method, the harmonic load of a single-phase alternating current (AC) voltage source is minimized. The welding power supply comprises a first rectifier circuit, a passive power factor correction circuit, a clock bridge circuit, a resonant converter and a second rectifier circuit. The resonant converter comprises a transformer and an oscillation loop with a first capacitor and a first inductor. A second capacitor and / or a second inductor are connected in parallel with the transformer. The value ratio of the first capacitor to the second capacitor is between 1-10, when the second capacitor is arranged at the primary side. The value ratio of the first capacitor to the second capacitor is the quotient of the square of the transformer ratio that is between 1-10, when the second capacitor is arranged at the secondary side. The value ratio of the second capacitor to the first capacitor is between 0.5-10 when the second capacitor is arranged at the primary side. The value ratio of the second capacitor to the first capacitor is the quotient of the square of the transformer ratio that is between 0.5-10 when the second capacitor is arranged at the secondary side.

A rotary wing aircraft includes a rotor system rotatable about an axis relative to an airframe. A plurality of blade assemblies is mounted to the rotor system. A higher harmonic control system is operable to generate a harmonic load at the rotor system according to a higher harmonic control signal. An active vibration control system is operable to generate vibration forces about the aircraft according to an active vibration control signal. A controller is operable to issue the higher harmonic control signal and the active vibration control signal to coordinate the higher harmonic control system and the active vibration control system to reduce vibration within the airframe.

An RF power amplifier device in which the circuit is provided on two separate dies which are attached together vertically. According to one embodiment of the present invention, the RF power amplifier includes a first die including an amplifying circuit for amplifying an RF signal, and a second die including at least one circuit component coupled to the amplifying circuit. The first die is vertically coupled to the second die, and the second die may be a flip chip and include harmonic loads and / or feedback circuit.

The invention relates to a harmonic source affine modeling method adopting interval monitoring data dimension reduction regression. The harmonic source affine modeling method comprises the following steps of S1, obtaining a harmonic voltage interval sample set; s2, according to the obtained harmonic voltage interval sample set, interval midpoint principal component analysis is carried out to obtain an affine expression of a harmonic voltage principal component; s3, based on the obtained affine expression of the harmonic voltage principal component, performing least square fitting on the affinecenter of the harmonic source model variable and the noise source part, and identifying parameters; and S4, combining the affine center and the noise source parameters to obtain an uncertain harmonicsource affine model. According to the method, expansion of interval arithmetic addition and subtraction operation can be inhibited, the ultra-width problem is solved, more accurate uncertain harmonicsource modeling is realized, and when the method is applied to harmonic load flow calculation, the calculation efficiency is high, and the convergence speed is high.

The invention discloses an active power filtering apparatus applicable to a circuit which comprises a system power supply and a harmonic load; the active power filtering apparatus comprises a transformer, an inverter and a modulation signal generation module; a primary side winding of the transformer is connected with the harmonic load in series to be connected to a loop which is formed by the system power supply and the harmonic load; the modulation signal generation module is used for generating a modulation signal of the inverter, wherein the modulation signal is formed by superposition of a reversely amplified transformer primary side fundamental current and positively amplified transformer primary side harmonic current; and the inverter is used for converting a direct current signal into an alternating current signal with the same frequency as the modulation signal to be injected to a secondary side winding of the transformer, so as to enable the transformer primary side fundamental wave equivalent impedance to be Z<1>+(1-<alpha>)Z<m> and to enable the transformer primary side n harmonic wave equivalent impedance to be nZ<1>+(1+<beta>)nZ<m>. Based on fundamental wave and harmonic wave magnetic flux mixed control, the transformer primary side relative fundamental wave short circuit and relative harmonic wave open circuit are realized, and the harmonic current is forced to flow to a passive branch, so that an active filtering effect is played.

A radio frequency (RF) generator for applying RF power to a plasma chamber includes a DC power supply (B+). A radio frequency switch generates the RF power at a center frequency f0. A low-pass dissipative terminated network connects between the DC power supply (B+) and the switch and includes operates at a first cutoff frequency. The switch outputs a signal to an output network which improves the fidelity of the system. The output network generates an output signal fed to a high-pass subharmonic load isolation filter that passes RF power above a predetermined frequency. A low-pass harmonic load isolation filter may be inserted between the output network and the high- pass subharmonic load isolation filter, and a high-pass terminated network may connect to the output of the output network. The high-pass terminated network dissipates RF power above a predetermined frequency. An offline short or shunt network may connect between the output of the switch and the input of the output network for shorting the output of the switch at predetermined frequencies.

The invention discloses a method and a system for judging the operating state of a transformer harmonic load. The implementation steps of the method include: acquiring an acoustic signal of a transformer to be detected; extracting independent characteristic parameters according to the acoustic signal of the transformer to be detected; inputting the independent characteristic parameters into the trained machine learning model; obtaining the current harmonic load operating state of the transformer to be detected, wherein the machine learning model is trained to include a mapping relationship between the independent feature parameters and harmonic load operating states. The system comprises a computer device programmed to perform the aforementioned method. The method and the system can effectively detect the operating state of the transformer harmonic load, will not contact a charging device, are convenient to operation, and are high in detection efficiency.

The invention relates to the field of a ground deformation test system for a shallow excavation tunnel and aims at providing a ground deformation test system for the shallow excavation tunnel under anoperation highway. The ground deformation test system of the shallow excavation subsurface tunnel under traffic load includes a highway tunnel simulation system, a traffic load simulation system anda monitoring system. According to the system, a servo loading device can be adopted to simulate the traffic load above the shallow excavation subsurface tunnel, and the surface settlement change, thechange of the surrounding rock contact stress and the change of acceleration and displacement of soil particles at a measurement point can be monitored by setting the vertical harmonic load combination of different sizes and frequencies to study the surface settlement law and the surrounding rock disturbance law, so as to further optimize the initial support and reinforcement parameters to guide design and construction.