8 results about "Negative inductance" patented technology

The application discloses a frequency and damping independently adjustable dynamic vibration absorber and a design method thereof, and relates to the technical field of semi-active control of structural vibration. The structure is composed of an inertial actuator and a shunt circuit. The shunt circuit comprises a negative inductance and negative resistance compensation circuit and an inductance-resistance-capacitance parallel circuit. Two wiring ends of a voice coil of the inertial actuator are connected with the shunt circuit to form a complete loop. The independent adjustment of the inherent frequency and the damping of the inertial actuator can be realized by adjusting the parameters of the shunt circuit. Therefore, the dynamic vibration absorber has the characteristics of controlling vibration of any disturbance frequency. The application does not need any mechanical driving device, and the inherent frequency and the damping adjustment of the dynamic vibration absorber are independent of each other.

The invention relates to the field of power electronic converter control, and discloses a high-power active variable inductor for a speed-adjustable driver and a control method thereof.The high-power active variable inductor comprises a positive inductor and a negative inductor, the positive inductor is a traditional physical inductor, and the negative inductor is obtained through equivalence of a single-phase inverter; by connecting the positive inductor and the negative inductor in parallel, the overall equivalent inductance value is increased, and meanwhile, a wider-range adjusting space is provided, so that a better filtering effect is achieved, the equivalent inductance value can be adjusted in a wide range, the power density is high, implementation is easy, three-phase imbalance can be dealt with, the electric energy quality of a speed-adjustable driver is improved, and the service life of a direct-current side filtering capacitor is prolonged; the problems that a direct-current side passive filter of an existing speed-adjustable driver is heavy, the inductance size of an active capacitor is difficult to reduce, and the adjusting range of an existing active inductor is narrow are effectively solved.

A subsynchronous oscillation suppression system disclosed by the present invention comprises a coupling transformer and a subsynchronous oscillation suppressor, a first DC power supply is connected with a power grid through a new energy power generation device, and a connection line of the new energy power generation device and the power grid is connected in series with a secondary side of the coupling transformer. The primary side of the coupling transformer is connected with the output end of the subsynchronous oscillation suppressor; the subsynchronous oscillation suppressor detects the output current of the new energy power generation equipment and judges whether subsynchronous oscillation occurs or not, if the subsynchronous oscillation occurs, the frequency of current oscillation is detected, and based on the frequency band, virtual negative inductive reactance is constructed through the coupling transformer to suppress the subsynchronous oscillation of the current; the method has the advantage that the current subsynchronous oscillation condition of new energy grid-connected power generation equipment such as a fan converter and a photovoltaic inverter can be inhibited.

The application discloses a kind of subsynchronous oscillation suppression systems, including coupling transformer and subsynchronous oscillation suppressor, first DC power supply is connected with power grid through new energy power generation equipment, new energy power generation equipment and the connecting line of power grid are connected with the secondary side of coupling transformer in series, the primary side of coupling transformer is connected with the output end of subsynchronous oscillation suppressor;Subsynchronous oscillation suppressor detects the output current of new energy power generation equipment, judge whether there is subsynchronous oscillation, if there is subsynchronous oscillation, the frequency of current oscillation is detected, and based on the frequency band, virtual negative inductance is constructed by coupling transformer to suppress current subsynchronous oscillation;The application has the advantages that: it can suppress the current subsynchronous oscillation of wind turbine converter, photovoltaic inverter and other new energy grid-connected power generation equipment.

The application provides a PT symmetric system based on a negative impedance transformer and an energy efficiency and distance improvement method thereof, and is characterized in that: at least one negative impedance transformer is connected in series on a wireless power transmission loop, the negative impedance transformer is constructed based on a transformer and an operational amplifier, wherein: the transformer considers leakage inductance and magnetizing inductance, a primary winding of the transformer is connected in series in the transmission loop, one end of a secondary winding of the transformer is grounded, and the other end is connected to an inverting input terminal of the operational amplifier, and the operational amplifier is equivalent to a negative resistance module or a negative inductance module by configuring a resistance element or / and an inductance element on a corresponding branch. The effect is that: the flexible adjustment of the inductance ratio is realized by constructing a negative inductance on the primary side, the power extreme point is accurately approached, and the output current is optimized in combination with the primary side compensation negative resistance, so that the problem of small power is solved from the core parameter level.

The invention relates to the field of power electronic converter control, discloses an ASD complex working condition management method and system based on a high-power active adjustable inductor, and aims to solve the problems of poor dynamic performance and short device service life caused by fixed passive filtering parameters of the ASD under the complex working conditions of three-phase imbalance, load switching, underload, overload and the like. According to the embodiment, an active variable inductor in which a positive inductor (such as a traditional physical inductor) and a negative inductor (equivalent to a single-phase inverter) are connected in parallel is adopted; the working condition state of the ASD at the current moment is recognized, then the negative inductance value is adjusted in a targeted mode, different working conditions are adapted, and the optimal filtering effect is achieved. The management method provided by the embodiment of the invention can flexibly deal with complex working conditions, improve the filtering performance, inhibit the DC side voltage fluctuation, prolong the service life of the capacitor, and improve the ASD power density and the operation reliability at the same time.

This invention discloses an adaptive virtual impedance optimization method and system, belonging to the field of power quality improvement technology. The method is executed by the VSG control module and includes: acquiring the system power angle and reactive power; outputting a fitted virtual resistance using a reactive power-virtual resistance regulator combined with a polynomial fitting curve method; real-time detection of the magnitude margin of the active power open-loop transfer function at the synchronous frequency; and selecting the output mode based on the margin detection result: if the margin meets the requirements, the fitted virtual resistance is used; if the margin is insufficient, a virtual negative inductor is engaged to reduce the power angle, and the system switches to directly outputting the virtual resistance by the reactive power-virtual resistance regulator. This invention, through an adaptive switching control strategy, effectively solves the problem of system instability caused by power coupling and synchronous frequency resonance in existing VSG control at large power angles, achieving power decoupling and SFR suppression over a wide range of power angles.