55results about How to "Improve harmonics" patented technology

A method and apparatus to implement parallel current mode control that is suitable for digital and analog implementation. A duty cycle algorithm is composed of a voltage term and a parallel current term which depends on the inductor current change between the inductor current value at the beginning of a switching cycle and the reference inductor current value at the end of that switching cycle. Parallel current mode control can be applied to all DC-DC converters, including both non-isolated and isolated topologies. It can also be applied to AC-DC converters with power factor correction.

A method and apparatus for use in improving linearity sensitivity of MOSFET devices having an accumulated charge sink (ACS) are disclosed. The method and apparatus are adapted to address degradation in second- and third-order intermodulation harmonic distortion at a desired range of operating voltage in devices employing an accumulated charge sink.

The invention discloses a parallel active filter based on a modularization multi-level converter and a control method of the parallel active filter and belongs to the technical field of power harmonic suppression in a medium-high voltage high-power occasion. The problem that an existing parallel active filter cannot carry out harmonic combination compensation effectively, so that power distribution network electric energy quality is poor is solved. The filter comprises the modularization multi-level converter, a current transformation unit, a harmonic current detecting unit, a current controller, a capacitor C and a power grid electric reactor LS. The modularization multi-level converter is of a half-bridge-type topological structure, and an upper bridge arm and a lower bridge arm of the modularization multi-level converter respectively comprise n submodules SMn. According to the control method, a carrier phase-shifting modulation method is used, so that under the same switch frequency, equivalent switch frequency is high, switching loss is reduced, meanwhile, a capacitive coupling voltage sharing and ring current suppression strategy is used, and capacitor voltages and direct current bus voltages of the submodules are kept stable. The parallel active filter is used for harmonic suppression of a power grid.

A method and apparatus for use in improving linearity sensitivity of MOSFET devices having an accumulated charge sink (ACS) are disclosed. The method and apparatus are adapted to address degradation in second- and third-order intermodulation harmonic distortion at a desired range of operating voltage in devices employing an accumulated charge sink.

The invention relates to a method for tracing a maximum power point of a photovoltaic miniature grid-connected inverter. When the output power of a photovoltaic cell is high, the traditional continuous operating mode and a maximum power point tracing method are adopted; and when the output power of the photovoltaic cell is low, intermittent operating mode is adopted, namely operation is continuously performed for a plurality of periods with set power, then operation is stopped for a while to store energy to a capacitor, and simultaneously maximum power point tracing is performed with voltage change rate in the energy storage period, so as to ensure that the photovoltaic cell is operated at maximum power point voltage. The method can effectively solve the problems that the efficiency of a traditional inverter is low when the illumination intensity is low, grid-connected current harmonic wave is large, and the like.

The invention disclosed an integrated filter inductance transformer, comprising a primary winding, a secondary winding, and LC resonant circuits of each winding characteristic harmonics, wherein the reactance L of the resonant circuits is a two-segment adverse-parallel symmetric interleaving winding which is wound with the primary winding and the secondary winding on the same iron core in a up-down symmetry manner. In the invention, the LC resonant circuits of each winding characteristic harmonics can eliminate the harmonic flux of the iron core, and prevent the harmonics from passing back, thereby realizing the function of filtering the primary winding harmonics; meanwhile, the transformer also has the function of reactive power compensation.

The invention discloses a radio-frequency switch circuit. The radio-frequency switch circuit comprises a common terminal and at least two switch branches, wherein the common terminal is used for receiving radio-frequency signals and inputting the radio-frequency signals into the switch branches corresponding to frequencies of the radio-frequency signals, and the switch branches are used for transmitting the radio-frequency signals during connection and suppressing harmonic components of the radio-frequency signals during transmission. The invention further discloses a method of the radio-frequency switch circuit for processing the radio-frequency signals.

The invention discloses a control circuit for a step-down circuit. The control circuit includes a reference signal generating circuit and a ramp signal generating circuit. The reference signal generating circuit receives a sampling signal and a current reference signal characterizing the inductor current to generate a first reference signal. The ramp signal generating circuit receives the first current, and obtains a ramp signal by charging and discharging the first capacitor; the first reference signal or/and the first current is proported. Before the ratio adjustment, the ratio of the firstreference signal to the first current is k1; after the ratio adjustment, a second reference signal and a second current are respectively obtained, and, the ratio of the second reference signal to thesecond current is k2; the ratio of k2 to k1 is shown in the description, where D is the main power tube duty cycle of the buck circuit; the reference voltage including the second reference signal is compared with the ramp signal to generate a control signal for controlling the main switch of the buck circuit to be turned on or off. The control circuit is capable of optimizing harmonics in the buckinput current.

The invention provides a dual-mode dielectric filter and a zero point adjustment method thereof, the dual-mode dielectric filter comprises a first resonant cavity and a second resonant cavity, and further comprises a plurality of dual-mode dielectric blocks located between the first resonant cavity and the second resonant cavity, the surface of each dual-mode dielectric block is provided with a metal layer, a first coupling structure is arranged between the dual-mode medium block adjacent to the first resonant cavity and the first resonant cavity, a second coupling structure is arranged between the dual-mode medium block adjacent to the second resonant cavity and the second resonant cavity, and the binding face of each dual-mode medium block and the adjacent dual-mode medium block is a coupling face, corresponding coupling windows are etched on the two attached coupling faces, the coupling window on each coupling face comprises at least one first strip-shaped window, the center line of the first strip-shaped window in the length direction is parallel to the first central axis of the coupling face, and the projection of the first strip-shaped window on the first central axis is far away from the center of the coupling face. Harmonic waves can be improved.

The invention relates to a multiphase motor control system based on the driving of a multiphase matrix converter, which comprises the multiphase matrix converter composed of 3*3n two-way switch tubes to form a 3*3n switch matrix, the on and off of each of the switch tubes are controlled by trigger pulse signals sent by a controller, an input side is connected with a three-phase alternating-current power source, an output side is connected with a multiphase motor with the phase number of 3*n (n is a positive integer which is more than or equal to 2), and the multiphase matrix converter serving as a driving system of the multiphase motor matches with the multiphase motor. The multiphase motor control system has the advantages that compared with the prior art, the efficiency is higher, the whole control system guarantees the multiphase motor to be provided with high accurate speed control performance and four phase limit operation of the multiphase motor, is capable of feeding energy back to the power system, and greatly improves the efficiency of the system during the operation of the multiphase motor; and the influence of the system to the quality of the electric energy of the power system is greatly reduced, and factors such as harmonic wave and power are improved greatly, particularly when the multiphase motor operates in low load.

The invention discloses a renewable energy micro-grid power supply railway energy route regulation and control method, which comprises an energy management layer for switching a current operation mode of a system based on real-time operation data and calculating to obtain a current and/or power instruction compensated by each route subsystem; the regional decision-making layer is used for distributing reference power and/or reference current of each routing subsystem; and the equipment control layer is used for coordinated control of each routing subsystem and the direct-current micro-grid. According to the invention, the regenerative braking energy of the train can be effectively recycled; renewable energy sources are accessed to a traction power supply system, and the energy consumption of a three-phase power grid is reduced; when the traction network has a short-time fault, the power supply capability within a certain period of time can be ensured; the fault-tolerant capability is realized; the electric energy quality problem of a traction power supply system can be effectively improved; and the tolerance requirement on internal power electronic devices in a high-voltage and high-capacity environment can be relieved.

The invention relates to a self-adaptive feedforward active noise reduction method based on a neural network, a computer readable storage medium and electronic equipment. The method is used for improving conditions of harmonic waves and intermodulation distortion generated by a link, and comprises the following steps: constructing a first neural network model, and based on an adaptive feedforwardactive noise reduction architecture, taking the constructed first neural network model as a feedforward filter in the architecture; and/or constructing a second neural network model, based on the adaptive feedforward active noise reduction architecture, using the second neural network model as a secondary channel estimate S '(z) in the architecture.

The invention relates to wind power generation devices, in particular to a permanent magnet wind power generator set, aiming at solving the problems that the improvement of output power of the existing permanent magnet wind power generator set is limited, and the like. The permanent magnet wind power generator set comprises a permanent magnet wind power generator and a frequency conversion device connected with the permanent magnet wind power generator, wherein the permanent magnet wind power generator is provided with 3n three-phase or single-phase armature windings which are electrically isolated from one another, and n is a natural number which is greater or equal to 2; the frequency conversion device comprises 3n power modules, each power module consists of a three-phase or single-phase pulse-width modulation (PWM) rectifying circuit, a direct current (DC) chopping circuit and a single-phase full-bridge inverter circuit; each three-phase or single-phase armature winding is connected with the input end of the rectifying circuit of the corresponding power module; the 3n power modules are divided into three groups, and the output ends of the single-phase full-bridge inverter circuits of the n power modules in each group are connected in series; three-phase alternating current (AC) output of the frequency conversion device is formed by the three groups of power modules which are in series connection. The output power of the permanent magnet wind power generator set is greatly improved, and reaches up to 2.5WM or more.

The invention discloses a magnetically-controlled static var compensator, which mainly solves the defects that in the prior art, the existing reactive compensation is stepped and low in accuracy, and cannot provide inductive reactive power or capacitive reactive power synchronously; the switching operation is frequent; the higher requirements of the electrical power system and users cannot be met. The magnetically-controlled static var compensator comprises a digital signal processor, a power supply, a capacitor bank or a filter bank, a keyboard, a liquid crystal displayer, a programmable logic controller, a reactive compensation unit, CSR (Controllable Shunt Reactors), and an AD (Analog-to-Digital) sampling circuit, wherein the output ends of the power supply, the capacitor bank or the filter bank and the keyboard are all connected with the digital signal processor; the input ends of the liquid crystal displayer, the programmable logic controller and the reactive compensator are all connected with the digital signal processor; the controllable shunt reactors are connected with the reactive compensation unit and the programmable logic controller; the input end of the AD sampling circuit is connected with the controllable shunt reactors, while the output end is connected with the digital signal processor. By virtue of the scheme, the magnetically-controlled static var compensator can reach the target of high cost performance and meet the actual demand, and is of high practical value and promotion value.

The invention provides a dual-mode dielectric filter and a zero point adjustment method thereof. The dual-mode dielectric filter comprises a first resonant cavity and a second resonant cavity, and further comprises a plurality of dual-mode dielectric blocks located between the first resonant cavity and the second resonant cavity, and each dual-mode dielectric block is sleeved with a metal cavity, a first coupling structure is arranged between the dual-mode dielectric block adjacent to the first resonant cavity and the first resonant cavity, a second coupling structure is arranged between the dual-mode dielectric block adjacent to the second resonant cavity and the second resonant cavity, a third coupling structure is arranged between every two adjacent dual-mode dielectric blocks, and the third coupling structures are spacers, the metal cavity and the adjacent spacer jointly form a resonant cavity, the spacer is provided with a coupling window, the coupling window comprises at least one first strip-shaped hole, the center line of the first strip-shaped hole in the length direction is parallel to a first central axis of the spacer, and the projection of the first strip-shaped hole on the first central axis is far away from the center of the spacer. Harmonic waves can be improved.

The invention provides a space vector modulation model voltage prediction method, and belongs to the technical field of power electronics. The method comprises the steps of firstly, establishing a discrete mathematical model of a converter, and obtaining a current value at the next moment through the mathematical model and state variables such as a grid-side voltage value, a current alternating-current-side current value and an output vector voltage value; secondly, enabling the obtained current value at the next moment to be equal to a reference value, obtaining a voltage value which should be output at the current moment, and then conducting equivalent transformation on a traditional model current prediction cost function to obtain a cost function based on the output vector voltage; andfinally, combining a simplified space vector modulation algorithm to obtain that the cost function of model voltage prediction control is minimum when three duty ratios are minimum so as to achieve anexpected control target. The algorithm is simple to implement, does not need to perform cyclic optimization like the traditional model current prediction, has good flexibility and expansibility, andis suitable for engineering application.

The invention discloses a totem pole power factor correction circuit and a control method thereof, a medium, a compressor and an air conditioner. The totem pole power factor correction circuit comprises a rectifier module, an inductor module, a capacitor module, a switch module and a control module, and the control module is used for controlling the rectifier module and the switch module to work in a high-frequency switch mode or a multi-pulse mode according to working parameters of the load. When working in a high-frequency switching mode, the input current waveform can be controlled to change along with the input voltage, so that the input current harmonic wave and the power factor are improved, the bus voltage is raised, and boost output is realized; and when working in a multi-pulse mode, the totem-pole power factor correction circuit can realize voltage-multiplying output with lower loss, and the totem-pole power factor correction circuit can realize boosting and voltage-multiplying functions, so that the totem-pole power factor correction circuit adapts to voltage requirements of different working parameters of a load, and keeps the advantage of high efficiency of the power factor correction circuit. The correction circuit is widely applied to the technical field of electronic power.

The invention discloses a harmonic and stray electromagnetic radiation restraining material and a preparation method thereof. The harmonic and stray electromagnetic radiation restraining material is prepared from the following components in parts by weight: a radar absorbent, liquid rubber, a sulfurizing agent, a mildew preventive, an anti-aging agent and a diluent. The preparation method comprises the following steps: heating the liquid rubber, the sulfurizing agent, the mildew preventive, the anti-aging agent and the diluent, and uniformly mixing according to a formula amount; adding the radar absorbent; fully mixing; grinding; performing curtain coating and drying to obtain a thin green body; preforming vulcanization to obtain the restraining material disclosed by the invention. The restraining material has the characteristics of high harmonic and stray electromagnetic radiation restraining capability and superior mechanical property, and the problem of interference of harmonic andstray electromagnetic radiation generated by large-power frequency equipment on peripheral precision electronic equipment can be solved effectively.

The invention discloses an APFC method of boost with no DC bias and no electrolytic capacitor. Two sets of high-frequency and self-excitation push-pull oscillation circuits are connected to a Boost circuit, so that the APFC process includes two low-frequency switch tubes controlled by a single-chip microcomputer MCU respectively regulate and control the high induction of the two sets of high-frequency and self-excitation push-pull oscillation circuits. The method improves the reliability when no electrolytic capacitor is used, and realizes control of accurate pulse duty ratio one by one. Real bottom switch QR is realized, heating is lowered, and output current with low ripples is realized. High power factor and power efficiency are realized, cost is low, and DC bias and electrolytic capacitor pollution problems can be prevented.