7 results about "Reactive power theory" patented technology

The application discloses a kind of adaptive compensation method and related device for three-phase current imbalance and harmonic, belong to power system technical field;The method is based on the instantaneous reactive power theory and the quick separation and instruction generation of fundamental wave positive sequence component and unbalance compensation component of sliding discrete fourier transform;Multi-objective model predictive current control with embedded repeated learning correction mechanism to achieve high-precision tracking of compensation current instruction and system circulation suppression;Multi-objective weight factor online dynamic adjustment mechanism based on fuzzy reasoning, according to the adaptive balance between the control emphasis of tracking accuracy, circulation suppression and switching loss according to the real-time operating state of the system;And, adaptive closed-loop management architecture based on the above module cooperation, drive active power electronic converter to generate compensation current, realize the comprehensive management of three-phase imbalance and harmonic and global optimization of system performance.

The invention discloses a single-phase SVG-based distribution network online ice melting asymmetric voltage suppression method and system, relates to the technical field of power system distribution network operation and control, and aims to solve the problem of voltage asymmetry in a distribution network single-phase ice melting process. The core is that a Z-type grounding transformer ice melting topology and a single-phase SVG compensation topology are integrated to construct a single-phase ice melting loop; a T / 4 delay operator is adopted to construct a virtual orthogonal system, accurate decomposition of current components is realized in combination with an instantaneous reactive power theory, a compensation current instruction is generated through double-loop control of a voltage outer loop and a current inner loop, and the SVG is driven to output controllable compensation current. The method can effectively counteract the inductive current of an ice melting loop, remarkably reduces the unbalance degree of the negative sequence voltage of the system to be within the national standard range, has the advantages of high response speed, high compensation precision and high adaptability, and guarantees the safe and stable operation of the online ice melting operation of the distribution network.

The application discloses a current-type SVG control method based on improved DC bus voltage synchronization, which comprises the following steps: based on synchronous outer loop equivalent analysis, the current control type SVG is equivalent to a power synchronization loop based on a phase-locked loop synchronization loop; according to the relationship between the DC bus voltage of the SVG and the output active power, the power synchronization loop is equivalent to a DC bus voltage synchronization loop; on the basis of the DC bus voltage synchronization loop, an improved DC bus voltage synchronization outer loop that integrates a phase-locked loop is designed; a detection method based on the instantaneous reactive power theory is adopted to realize reactive current detection and complete the design of a reactive power compensation loop; a quasi-proportional resonant controller QPR and a proportional integral controller PI are adopted to design a current control inner loop; and the above loop designs are combined to jointly construct a control system of the current-type SVG, so that stable control of the current-type SVG is realized. The application can improve the stability under a weak power grid and help the stable grid connection and consumption of new energy.

The invention discloses a reactive power dynamic compensation control method for a tractive power supply system, which comprises the following steps of: acquiring the amplitude and phase of equivalent power supply voltage corresponding to a three-phase access point of a thyristor control compensator by measuring the primary side voltage of a transformer and performing conversion calculation; detecting voltage and current of the two-phase traction network in real time, and calculating to obtain total reactive power needing to be compensated based on an instantaneous reactive power theory; determining a trigger angle of each phase of thyristor according to the total reactive power and the voltage amplitude; and by comparing the trigger angle with the phase of each phase voltage, generating and outputting a trigger signal for driving a thyristor to be conducted. The method can realize the dynamic tracking compensation of the reactive power of the traction network, effectively improves the power factor of the traction substation, reduces the power regulation electric charge expenditure, improves the power quality of the power grid, and expands the application of the dynamic reactive compensation technology in the electrified railway.

The invention discloses a current type SVG control method based on improved DC bus voltage synchronization, and the method comprises the steps: enabling a phase-locked loop-based synchronous loop of a current control type SVG to be equivalent to a power synchronous loop based on synchronous outer loop equivalent analysis; according to the relation between the SVG direct current bus voltage and the output active power, a power synchronization loop is equivalent to a direct current bus voltage synchronization loop; on the basis of a direct-current bus voltage synchronous loop, an improved direct-current bus voltage synchronous outer loop fused with a phase-locked loop is designed; a detection method based on an instantaneous reactive power theory is adopted, reactive current detection is achieved, and reactive compensation loop design is completed; a quasi-proportional resonance controller QPR is connected in parallel with a proportional-integral controller PI to design a current control inner loop; in combination with the loop design, a control system of the current type SVG is jointly constructed, and stable control over the current type SVG is achieved. According to the method, the stability under the weak power grid can be improved, and stable grid-connected absorption of new energy is facilitated.

This invention belongs to the field of converter control technology, specifically disclosing a converter grid-connected harmonic suppression method and system based on the TD3 algorithm and instantaneous reactive power theory, including the following steps: acquiring three-phase current signals; and obtaining observed state variables from the three-phase current signals based on instantaneous reactive power theory and the TD3 algorithm. S t ; Observe the state quantity S t Input the trained TD3 agent and obtain action values. a t ; For action values a t Coordinate transformation and SVPWM processing are performed to obtain a modulation signal; the modulation signal is then applied to the grid-connected converter. This invention has the advantages of high dynamic response speed, wide harmonic suppression bandwidth, and strong adaptability, and can effectively solve the dynamic suppression problem of harmonic pollution in new energy grid-connected scenarios.

The invention discloses a control method of a network-forming type active filter, the active filter comprises a power outer loop control unit and a voltage and current inner loop control unit, and the power outer loop control unit comprises a direct current bus voltage loop, an active power outer loop and a reactive power outer loop. The voltage and current inner loop control unit comprises an AC voltage loop and an AC current loop. The active filter is operated in a network construction mode, and the voltage source characteristic of the active filter can suppress the source load resonance problem to the greatest extent; for a balanced load and an unbalanced load, an instantaneous reactive power theory and a TTA harmonic detection algorithm are respectively adopted to obtain a harmonic voltage instruction, so that load-side harmonic suppression is realized; a harmonic voltage instruction is obtained by carrying out harmonic detection calculation on load current, and load side harmonic treatment is carried out, so that the function of actively carrying out harmonic treatment on the network construction type converter is realized; the harmonic impedance characteristic reconstruction of the active filter is realized through harmonic voltage source control, and the problem of multi-machine parallel resonance can be effectively solved.