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.

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.

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 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.

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 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.

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.