60 results about "Resonance problem" patented technology

The invention discloses an active damping control device for an LCL (Lower Control Limit) filtering PWM (Pulse-Width Modulation) current converter, which is improved to solve the problem that an additional sensor is required to be introduced for active damping control, and a current control structure is innovated. The invention designs a novel AC-side current feedback compensation damping control mode based on a double proportional control module and a band-pass filter. Through current on the AC side, the controlled quantity of the active damping control device is compensated. Firstly, the method is taken as active damping control without additionally arranging a damping resistor and then directly compensates through the current on the AC side, so that the additional sensor is not required to be arranged. The active damping control device has the benefits that on the basis of resonance problem that an LCL filter is restrained to be introduced, the practical damping resistor and the additional sensor are not required to be additionally arranged, so that both the efficiency and the cost of systems can be improved to a certain degree.

The invention discloses a multi-fan grid-connected resonance analysis method. The method comprises the following steps: on the basis of an output impedance model of an inverter, establishing a grid-connected equivalent model of a wind power plant; establishing a cable equivalent model according to the cable distribution characteristic under a harmonic state, and establishing the equivalent impedance of fan output power at a PCC (Point of Common Coupling) according to a relationship between the absorption power of the PCC and the fan output power to obtain the total impedance of a distributed wind power grid-connected system. The multi-fan grid-connected resonance analysis method has the advantages that the total impedance is calculated by establishing a distributed wind power grid-connected system model recorded with the cable and fan output power; the system model more accords with practical situations and has an application value and a practical significance for the resonance problem in an accurate analysis system.

The invention discloses a tower drum resonance avoiding and crossing control method of a wind turbine generator and the wind turbine generator, and belongs to the field of wind turbine generator control. The tower drum resonance avoiding and crossing control method comprises the following steps of: monitoring wind wheel rotation frequency f, and comparing the wind wheel rotation frequency f with apreset rotation speed resonance region; setting the rotation speed resonance region as follows: setting a rotation speed resonance region according to inherent frequency ft of a tower drum, wherein the rotation speed resonance region comprises rotation speed lower limit, rotation speed upper limit and a rotation speed area between the rotation speed lower limit and the rotation speed upper limit;and converting ft into rotation speed St, wherein the size of the rotation speed St is within a range from the rotation speed lower limit value Sm and the rotation speed upper limit value Sx; and when the wind wheel rotation frequency is within the rotation speed resonance region, controlling wind wheel rotation speed to quickly rise or drop to pass through the rotation speed resonance region according to a current state of the wind turbine generator. A rotation speed resonance region is set near a crossed joint of wind wheel rotation speed and tower drum inherent frequency, reasonable rotation speed resonance region upper and lower limits are set, and the rotation speed of the wind turbine generator is controlled to quickly rise or drop, so that the wind turbine generator passes throughthe rotation speed resonance region, and therefore, the tower drum resonance problem is solved.

The invention provides a vehicle resonance detection alarming method, a vehicle resonance detection alarming device, and a vehicle resonance detection alarming system, and relates to the vehicle detection field. The vehicle resonance detection alarming method is characterized in that a time domain signal of vehicle frame vibration accelerated speed is acquired, and is converted into a frequency domain signal; whether a first significant peak value exists in the frequency domain signal is determined, and the signal amplitude of the first significant peak value is the signal having the signal amplitude greater than the signal amplitude mean value by the first preset multiple; when the answer is yes, the rotating speed signal of the vehicle engine is acquired, and a main order frequency of a rotating speed signal is calculated; whether the frequency of the first significant peak value is superposed with the main order frequency is determined; when the answer is yes, the resonance phenomenon of the vehicle is determined, and the alarming prompt is transmitted to the driver. The real-time analysis and determining of the whole vehicle resonance state can be carried out, and the resonance problem is found timely, and then the driver is prompted to accelerate or slow down in order to prevent the current resonance vehicle speed, and therefore the driving fatigue of the driver generated in the whole vehicle resonance state is prevented.

The invention relates to the technical field of antennas, in particular to a low profile ultra wide band antenna array setting method which overcomes the shortcoming in ultra wide band array design. A low profile ultra wide band design method is provided. An image making mode is adopted to solve the resonance problem caused by the fact that slot antenna units are adopted to form the array, then design is conducted on the array units based on the high cross coupling effect, and finally a parasitic element is adopted to adjust the working band width of the array. The method achieves antenna low profile ultra wide band characteristics and has good manufacturability and assembly capability. A metal wall image making mode is arranged between a BAVA antenna medium and a BAVA antenna floor, meanwhile the directional diagram product theorem and the electromagnetic period boundary theory are utilized to remove mutual coupling of the array units and achieve the aim of increasing band width.

The invention discloses a dynamic cancellation circuit applicable to output direct-current offset of a buck converter and belongs to the technical field of electronic circuits. The dynamic cancellation circuit comprises a ripple generation circuit and a ripple superposition circuit. The dynamic cancellation circuit has the advantages that duty ratio information is added into the ripple generation circuit, voltage at a connection node SW of an upper power tube S1 and a lower power tube S2 is sampled directly to simulate to generate ripples as same as inductive current in phase, and the ripples are superposed on VFB (voltage feedback) to enable the VFB to be equal to preset VREF (voltage reference), so that a PWM (pulse-width modulation) comparator is controlled to overturn normally, system stability is enhanced, the resonance problem caused by output voltage phase lag which results from too small equivalent series resistance of an output capacitor is avoided, output voltage precision of the converter is improved, contradictions between the system stability and the precision of a valley value detection mode under traditional ripple control are overcome, and direct-current offset of output voltage can be dynamically cancelled under different application conditions, namely under different input and output voltages.

The invention provides an on-orbit modal computing method for a rotatable flexible solar array satellite; a whole-satellite structural dynamics characteristic equation is made based on the establishment of a flexible satellite dynamics hybrid coordinate equation; when a flexible solar array rotates to a different angle, satellite rotational inertia and translational coupling coefficient and rotational coupling coefficient of the solar array relative to the center of whole-satellite gravity are calculated and substituted to the characteristic equation to solve a characteristic value, namely corresponding whole-satellite on-orbit modal frequency of the solar array in each mode. The problem of estimating on-orbit mode of a flexible satellite is solved, and the on-orbit mode of the flexible satellite is an important input to whole-satellite dynamics frequency-spectrum planning and is applicable to avoidance of the coupling resonance problem possibly occurring after a satellite is on orbit.

The invention discloses a method for obtaining a resonance group constant by aiming at the dual heterogeneous fuel of a nuclear reactor. On the basis of an ultrafine group resonance calculation method, an energy spectrum obtained by solving a neutron slowing-down equation by a lattice cell of which the fuel region is homogenized and a point section corrected by a Shmakov method on the basis of a dual heterogeneous geometrical parameter are subjected to merging on the basis of volume flux weight to obtain the resonance group constant. Compared with a non-deterministic theory Monte Carlo method, the method disclosed by the invention can obviously improve calculation efficiency and economic efficiency. Meanwhile, the coupling of two methods enables a deterministic theory ultrafine group resonance calculation method to own a capability of processing a complex dual heterogeneous geometric resonance problem, the application of the ultrafine group resonance calculation method can accurately process a resonance interference effect which is in the presence in fuel and can obtain accurate homogenized resonance group constant.

The invention belongs to the technical field of vibration testing, particularly relates to a modal testing method for a turbine generator base, and aims at providing a horizontal modal testing method for the turbine generator base which is strongly-targeted, reliable in testing result, and beneficial for solving the base resonance problem so as to solve defects in the prior art. The method can carry out the horizontal modal test in a targeted manner on the inherent vibration performance of the generator base on which the set is running on-line or shutdown, and effectively restore the inherent vibration characteristic of the generator stator base in the actual installation state and the operation state. The method is simple to operate and has good enforceability. The method has the advantages of stable testing results, the high accuracy rate and high resonance diagnostic values by setting the parameters such as the test direction and the concern frequency range of the vibration.

The invention provides an energy storage and conversion system which is applied to fixed fields such as load regulation in power grid, widn power generation and the like. Flywheel energy storage is adopted, a routine synchronous or asynchronous motor / generator is connected with a power grid, and homopolar electromagnetic transmission (HET) is adopted as stepless speed change torque change transmission equipment between a flywheel and a motor. The better scheme of the flywheel is to adopt a vertical type flexible flywheel structure or a suspension type flexible flywheel structure, and the suspension type flexible flywheel structure is especially suitable for the flywheel of large mass. The suspension type flexible flywheel structure can solve the unbalance and resonance problem when a rotor is simply supported by combination of a flywheel body and a rotating shaft as usual. An axial support permanent magnet bearing on a vertical type rotating shaft can solve the gravity support problem of the large-mass flywheel. A flexible connection multi-body flywheel body of the flywheel facilitates manufacturing and improvement of energy storage volume density. An energy input / output conversion system composed of the HET and a common motor solves the problem that a motor is large in calorific power and poor in heat radiation, cannot be limited in the aspect of transmission power, and is high in equipment power density, low in cost and high in energy conversion efficiency.

The invention discloses a gas turbine compressor blade frequency modulation design method, and belongs to the technical field of compressor blade reliability research. The purpose of the method is tosolve the problem that the compressor blade resonates within the rotating speed range where the compressor blade works frequently. The method comprises the steps that firstly, carrying out vibration calculation on compressor blades with the resonance problem; determining risks existing in blade vibration according to a calculation result and a blade vibration design criterion, and further determining a target frequency value of the blade; according to the qualitative relation between the blade frequency change and the blade profile thickness adjustment, and giving the specific thickness valueof the blade preliminarily; performing vibration calculation on the blade, summarizing a quantitative relationship between the blade frequency change and blade profile thickness adjustment, and givinga scheme II according to the relationship and an initially determined target frequency value; and finally finding out a reasonable blade profile adjustment scheme through fine adjustment. The methodis suitable for the frequency modulation design of compressor blades of various gas turbines and aero-engines in ships and industries.

The invention discloses an inverter circuit that can be applied to an inverter such as a photovoltaic inverter. An embodiment of the invention further provides an inverter and a photovoltaic power generation system. Both the inverter and the inverter in the photovoltaic power generation system comprise inverter circuits disclosed in the invention. According to the inverter circuit, based on an HERIC topology inverter circuit structure, by the bridging of a third capacitor and a fourth capacitor on buses on a first vertical bridge and a second vertical bridge, in the process of converting the inverter circuit from a turn-on phase to a follow current phase, the third capacitor and the fourth capacitor can stabilize a voltage fluctuation in the HERIC topology due to different turn-off speeds of a switching tube, therefore, the resonance problem caused by the voltage fluctuation is prevented, the problem of the resonance interference is solved, the electro magnetic compatibility (EMC) of equipment and the system which can work normally in an electromagnetic environment and do not form electromagnetic disturbance which cannot be borne by any item in an environment can satisfy the requirements of EMC related standards.

The formation of an assembled unit consisting of an annular capacitor [a wound, metallized dielectric capacitor in the shape of a closed path ring] with other power conversion components arranged and attached in manners uniquely allowed by the ring design will allow higher density converter designs [power / unit volume]. The resulting short connection paths between the capacitor element and the switching semiconductors also provide a very low inductance path that minimizes voltage spikes on the switching semiconductors as a result of turn-off di / dt. The capacitor serves as a short time current source and sink for the switching semiconductors. With the described configuration the RMS current seen by the capacitor can be made more volumetrically uniform enabling more uniform capacitor rise. The single capacitor configured as described also mitigates bus resonance problems often observed in prior art when multiple discrete capacitors are connected in parallel.

The invention provides an electronic ballast of street lamps, comprising: a power input circuit, an electromagnetic interference process circuit, a rectifier filter circuit, an inversion driving circuit, an inversion circuit and a frequency drift circuit. The frequency drift circuit is used for adjusting output frequency of the inversion driving circuit so as to put the working frequency of the inversion circuit in a periodical changeable state. The output frequency of the inversion driving circuit is adjusted by the frequency drift circuit as the frequency drift circuit is installed in the electronic ballast to solve the resonance problem of lamp and sound of high pressure gas discharging. Thus, the high pressure gas discharging lamps using the electronic ballast are able to be widely applied in street lamps such that social energy is greatly saved.

The invention discloses a method for improving the parallel connection stability of a photovoltaic inverter and an energy storage inverter. The method specifically includes the following steps that: the output voltage uov, output current iov and inductive current iLv of the energy storage distributed power inverter are collected; the average active power Px and average reactive power Qx of a voltage controlled inverter are obtained by means of the calculation of an average power calculation method; the average active power Px and the average reactive power Qx are processed by a droop controller, so that an output voltage reference value uref can be obtained; the output current iov and parallel resonance suppression negative impedance zvir are multiplied, so that a virtual voltage uvir canbe obtained; the uref and the uvir are added up, so that a voltage regulator command voltage u'ref can be obtained; difference between the U'ref and the uov is obtained, so that iref can be obtained;difference between the iref and the iov is obtained, and the difference is processed by a regulator, so that modulation signals can be obtained; and modulation processing is performed on the modulation signals through a modulation module, so that the switching tube driving signals of the inverter can be obtained, the controller of the inverter controls the inverter according to the switching tubedriving signals. With the method of the invention adopted, resonance problems generated by the parallel connection of the inverters under different control modes can be solved.

The invention discloses a hydraulic cylinder control valve without unloading impact resonance, which overcomes the problem that impact resonance is generated by the unloading of a hydraulic control one-way valve of a conventional hydraulic cylinder. The hydraulic cylinder control valve without unloading impact resonance is characterized in that: a sealing diameter of a valve opening of a first valve core inside a valve body is same as a diameter of a sealing section and a diameter of a liquid return section; and the diameter of a control section is smaller than the diameter of a liquid return section. The beneficial effects are that: as the sealing diameter of the valve opening of a first valve core is same as the diameter of the sealing section and the diameter of the liquid return section, the unloading impact resonance problem of the control valve of the hydraulic cylinder is solved; as the sealing diameter of the valve opening, the diameter of the sealing section and the diameter of the liquid return section can be increased equivalently, and the diameter of the control section can be reduced at will based on a need, the control pressure is unlikely too low, and no false operation is generated; and a secondary-hole one-way valve arranged in a secondary hole inside the valve body or a plate-shaped connecting one-way valve or a tubular one-way valve outside the valve body are used for raising a column, so that needs of big channel for dropping the column, a small channel for raising the column, and joint control of a balancing jack and a lifting jack while the column is raised are satisfied.

The invention discloses a connector, which comprises an insulation body, multiple grounding terminals and multiple pairs of signal terminals, wherein the multiple grounding terminals are kept in the insulation body; the multiple pairs of signal terminals are kept in the insulation body; the multiple grounding terminals and the multiple pairs of signal terminals are arranged into a multi-row multi-column matrix; the matrix comprises multiple columns of grounding terminals and multiple columns of signals terminals; the multiple columns of grounding terminals and multiple columns of signals terminals are arranged alternately in the row directions of the matrix; and a mutual stagger predetermined distance exists between connection pins of the multiple grounding terminals in each column of grounding terminals in the row direction of the matrix. Thus, the impedance of the grounding terminals is optimized, and the resonance problem of the grounding terminals is eliminated.

The invention relates to a vibrating diaphragm and a manufacturing method thereof. The manufacturing method comprises the following steps: S1: providing a silica gel film; S2: treating the silica gelfilm to thin the silica gel film to form a silica gel thin film; S3: providing graphene, graphite powder, a thinner and glue; S4: adding graphene or a mixture graphene and graphite powder into the thinner, and stirring evenly to form graphene suspension or graphene-graphite powder suspension; S5: evenly coating the graphene suspension or the graphene-graphite powder suspension on the surface of the silica gel thin film, and performing drying to form an intermediate layer, wherein the intermediate layer is a graphene layer or a graphene-graphite powder layer; S6: evenly coating the glue on thesurface of the intermediate layer, performing a drying treatment to cure the glue on the surface of the intermediate layer to form a glue layer, and finally forming a thin film; and S7, forming and dividing the thin film into a finished product vibrating diaphragm in a hot pressing manner. The vibrating diaphragm adopts the silica gel thin film as a base material to better suppress the resonance problem and reduce the distortion of the vibrating diaphragm, the resonance frequency f0 is lower, and the low frequency characteristics are better.

Provided is a novel shielding cable comprising at least one signal line and two metallic conductive shielding tapes covering the periphery of the signal line. The metallic conductive shielding tape is formed by a metallic foil covering a side of a plasticity base material. The metallic foil of the first metallic conductive shielding tape faces outwardly, is spirally wound around the signal line, and defines a plurality of first spiral coils. The metallic foil of the second metallic conductive shielding tape faces inwardly, reversely spirally wound around the first metallic conductive shielding tape, and defines a plurality of second spiral coils. Continuous electrical contact is formed between the first metallic conductive shielding tape and the second metallic conductive shielding tape. The two metallic conductive shielding tapes are wound in a crossed manner such that the metallic foils of the two metallic conductive shielding tapes can be completely and tightly combined and cannot generate periodic breakpoints, thereby guaranteeing continuity of a conductive surface. Thus, a resonance problem generated by periodic fluctuation of shielding conductive surface capacitance is solved and an effect of solving a high-frequency point abrupt attenuation.

The invention provides a resonance suppression method for a humanoid flexible arm, particularly provides a resonance suppression method for a humanoid flexible arm based on a PR controller, and belongs to the field of vibration control. An output shaft of a joint motor end of the humanoid flexible arm is connected with a fixed end of an arm connecting rod through a harmonic reducer, and the inherent flexibility of a flexible gear of the harmonic reducer introduces a resonance frequency point to cause the resonance problem of the humanoid robot arm. According to the resonance suppression methodfor the humanoid flexible arm, the PR controller is introduced into a control system of the humanoid flexible arm, the disturbance suppression capability of the PR controller at a specific frequencypoint is utilized, so that the resonance caused by the fact that the output signal frequency of the controller is equal to the resonance frequency of the humanoid flexible arm is avoided, and the operation performance and the stability of the humanoid flexible arm are improved.

The diaphragm of a high fidelity speaker is constituted of framework members, and a member filling between the framework members. The framework member is a flat plate, and all framework members are arranged radially outward from the center of the diaphragm in parallel with the vibrating direction and bonded to each other in the radial center and then bonded to a drive section. The framework member has high rigidity. The filling member is composed of a foamed body. The diaphragm has no skin and thereby has no resonance problem. Sound is radiated from the filling member. A suspension has rod-like members arranged in a line and bonded to the opposite ends of a first leaf spring, wherein second leaf springs are bonded to the opposite ends of the rod-like members at right angles thereto, and the ends of the second leaf springs are bonded to unmovable portions of the speaker. Intrinsic resonance occurring in the suspension is very small and displacement is small in directions other than the vibrating direction. An edgeless flat plate speaker system reproducing a sound with high fidelity with no impact of intrinsic resonance can be constituted using this invention.

The invention discloses a blocking filter capable of effectively suppressing three forms of subsynchronous resonances. The blocking filter comprises at least two orders of (called a Y order and a Y+ order) of parallel resonance circuits which are connected in series, wherein the resonant frequency of one order (Y order) corresponds to an inherent torsion frequency of a generator set shaft system and is used for suppressing a machine-network composite resonance problem and a transient torque amplification problem; and the resonant frequency of the other order (Y+ order) corresponds to an asynchronous excitation frequency of an asynchronous excitation problem caused by the Y-order blocking filter. A high-Q-value reactor is adopted by the resonance circuit (Y order) for correspondingly solving the machine-network composite resonance problem while a low-Q-value reactor is adopted by the new resonance circuit (Y+ order) for correspondingly solving the asynchronous excitation problem; and a Q value of the high-Q-value reactor is 100-220 in general and the Q value of the low-Q-value reactor is 30-60 in general.

The invention relates to the technical field of transformers, in particular to a high-voltage large-capacity vibration-resistant transformer arranged on a draft tube deck of a hydropower station and adesign method thereof. The design method comprises the following steps of: firstly, measuring and analyzing the vibration characteristics of the draft tube deck of the hydropower station, carrying out vibration characteristic analysis on the initially arranged transformer modeling, and comparing the vibration characteristics of the draft tube deck and the transformer, wherein, on one hand, the resonance problem is avoided, on the other hand, the response of the transformer to the vibration of the draft tube deck is analyzed, the structural vibration resistance reinforcement is carried out onthe transformer, and the reliable operation of the transformer is ensured. In addition, an on-line monitoring system of the transformer monitors the running condition of the transformer in real time,thereby further ensuring the reliability.

The invention discloses a parameter optimization method of a power assembly mounting system used for a heavy chassis. The method comprises the steps of 1, calculating an engine excitation frequency range and a pavement excitation frequency range, thereby determining an initial inherent frequency range and an optimal frequency range of the power assembly mounting system; 2, performing modeling to obtain a mode analysis model of the power assembly mounting system; 3, performing optimization matching on mounting geometric parameters and mounting characteristic parameters; 4, calculating a currentinherent frequency of the power assembly mounting system, judging whether the current inherent frequency is in the optimal frequency range or not, and if yes, executing the step 5, otherwise, returning to the step 3; and 5, outputting the mounting geometric parameters and the mounting characteristic parameters. By optimizing the parameters of the power assembly mounting system used for the heavychassis, the vibration quality of the power assembly mounting system can be effectively improved, so that the power assembly mounting system achieves a vibration reduction effect while avoiding the resonance problem.

The present invention discloses a quadratic voltage multiple unit DC-DC converter for a photovoltaic system. The converter is improved in boost performance through fusion of a boost unit structure ofa voltage multiple unit compared to a traditional boost converter. Compared to a traditional boost unit of a voltage multiple unit structure, the converter has a good boost voltage performance with the increasing of a duty ratio. The quadratic voltage multiple unit DC-DC converter further fuses a quadratic boost circuit structure to further improve the voltage gain, the number of switch tubes S isnot increased, the control difficulty of the system is not increased, and the electrical stress of the switch tubes S and an output rectifier diode Do cannot be influenced. Besides, the quadratic voltage multiple unit DC-DC converter further fuses a leakage inductance clamping circuit structure to allow the energy of the leakage inductance of a coupled inductor to have a releasing loop on a basisof improving the converter boost capacity by employing the coupled inductor so as to avoid the circuit resonance problem caused by leakage inductance energy and improve the circuit efficiency.

The invention discloses a self-priming computer shock-absorbing case, which comprises: a case frame and an annular washer, the annular washer is arranged on the bottom edge of the case frame, and the edge of the annular washer is provided with an annular guard extending upward to the outer surface of the case frame. The bottom of the annular gasket is concavely provided with an annular groove, and several supporting columns are arranged at intervals in the annular groove, and the bottom of the supporting columns is respectively provided with suction cups, and the concave of the annular groove is provided with A limit hole corresponding to the support column, and the top of the support column is inserted into the limit hole. Through the above method, the self-priming computer shock-absorbing chassis of the present invention wraps the bottom of the chassis frame through the annular gasket and the annular sheath to improve the buffering and shock-absorbing effect, reduce the impact of vibration on the desktop or the ground, and avoid resonance problems. Using the suction cup to absorb the desktop or the ground improves the structural stability, avoids shaking problems, and has good structural stability.

The invention discloses a cascaded multi-voltage unit DC-DC converter for a photovoltaic system. The cascaded multi-voltage unit DC-DC converter combines a boost unit structure of a multi-voltage unit, compared with a conventional boost converter, the boost performance is improved; compared with the boost unit of a conventional voltage doubler unit structure, the converter has superior boost voltage performance as the duty ratio increases. The cascaded multi-voltage unit DC-DC converter also combines a cascaded boost circuit structure, the voltage gain is further improved, the number of switching tubes S is not increased, the control difficulty of the system is not increased, and the electrical stresses of the switching tubes S and an output rectifier diode Do are not affected. In addition, the cascaded multi-voltage unit DC-DC converter also combines a leakage inductance clamp circuit structure, on the basis of using a coupled inductor to improve the boost capability of the converter,the energy of the leakage inductance of the coupled inductor is released, thus the circuit resonance problem caused by leakage inductance energy is avoided, and the efficiency of the circuit is alsoimproved.