6 results about "Root locus" patented technology

The invention discloses a sending-end power grid frequency characteristic analysis method, system and device considering multiple dead zones and multiple control modes and a medium, and belongs to the technical field of power system planning operation. Constructing a droop control model of the new energy, a virtual inertia control model, rotor motion models under a plurality of synchronous units, a second-order speed regulation system model, a frequency regulation model of a load, a set value of a primary frequency modulation dead zone of the synchronous units, a direct current frequency limit control model, a dead zone set value and virtual inertia control of a direct current sending part; identifying parameters of the synchronous unit speed regulation system through a time domain simulation method; establishing a power grid frequency response model; and analyzing frequency characteristics and influence factors of the sending-end power grid by adopting a Routh criterion and a root locus method. The auxiliary sending end power grid planning operation provides decision support for a new energy control mode and a control mode of a direct current power transmission system.

This invention discloses a method and apparatus for determining the optimal position of the shaft damping controller in a grid-type doubly-fed induction generator (DFIG). A damping controller based on rotational speed signals is added to different control loops. The differences in shaft damping caused by adding the damping controller to different control loops are compared based on the root locus diagram of the DFIG. Results show that implementing the damping controller in the active power loop reduces transmission system damping compared to the voltage loop. Furthermore, applying the damping controller to the q-axis voltage provides a better damping enhancement effect than applying it to the d-axis voltage.

The application discloses a kind of position sensorless control parameter setting method and device, the present application is according to the voltage model of permanent magnet synchronous motor under rotating coordinate system, establish the local transfer function of position sensorless, determine the relationship of damping ratio, natural frequency and position sensorless proportional integral parameter, and the influence of damping ratio and natural frequency on system steady error, using small signal model stability analysis method to carry out system stability analysis, obtain system linear state model, according to the relationship of damping ratio, natural frequency and position sensorless proportional integral parameter, the influence of damping ratio and natural frequency on system steady error, system linear state model, obtain leading eigenvalue trajectory graph, according to leading eigenvalue trajectory graph and preset actual demand, realize control parameter setting, avoid the tedious parameter adjustment in practical application, can significantly improve the motor control performance based on sensorless technology.

The application discloses an inner loop controller parameter determination method, system, device and storage medium, and belongs to the technical field of power electronic power systems. The method comprises the following steps: acquiring an open-loop transfer function of a current loop of a power grid; determining proportional-resonant controller parameters through the open-loop transfer function, wherein the proportional-resonant controller parameters are proportional gain and resonant gain; determining a root locus according to the open-loop transfer function, and determining the proportional gain according to the root locus; and determining the resonant gain according to the proportional gain and the proportional-resonant controller parameters. The LCL type filter used by the support type converter of the power grid can be quickly determined to obtain the inner loop controller parameters of the support type converter.

The invention discloses a network-related performance improvement method considering multi-degree-of-freedom control of network construction type energy storage, and the method comprises the steps: expanding the control degree of freedom based on a control structure of an MMC, and achieving the multi-degree-of-freedom control and a fourth-order differential equation of the network construction type energy storage; according to a fourth-order differential equation of the system, a linearized Jacobian matrix of the system is obtained by determining a steady-state working point of the constructed network type energy storage; based on a Jacobian matrix of a network construction energy storage multi-degree-of-freedom control converter system, a characteristic equation of the system at a steady-state equilibrium point can be constructed, and a root locus curve of the system is further drawn; and based on the root locus curve characteristics of the system, determining the optimal network-related performance of the system through the positions of the poles and the zero points away from the imaginary axis. The method is suitable for setting the parameters of the network-forming type energy storage converters of various scales, is used for improving the network-related performance of the energy storage system, and is particularly suitable for a modern electric power system with high-proportion new energy access.

The invention discloses a dynamic root locus PI-based totem pole power factor correction circuit control method and system, and the method comprises the steps: S1, building a state equation of a large circuit signal model based on the operation state of an AC / DC circuit; s2, based on the state equation of the large circuit signal model, establishing a small circuit signal model of the totem-pole PFC by adopting a disturbance method; s3, obtaining a transfer function based on the small circuit signal model; s4, performing calculation in combination with the transfer function and a current equation of a small circuit signal model to obtain a current inner loop transfer function; and S5, performing root locus analysis on the current inner loop transfer function to obtain a dynamic locus PI control parameter, and realizing control of the totem pole power factor correction circuit based on the dynamic locus PI control parameter. According to the control method, input current harmonics can be reduced, the power factor and the self-adaptive performance of the circuit are improved, and the wide-range voltage regulation capability is preliminarily obtained.