10 results about "Root locus" patented technology

The invention discloses a GaN HEMT (High Electron Mobility Transistor) driving method for quantitative suppression of false triggering oscillation. The method comprises the following steps: calculating turn-off transient process time; establishing a false triggering oscillation equivalent circuit model, deducing an oscillation system characteristic equation, performing root locus analysis on the oscillation system characteristic equation, and delimiting a design range of RC parameters with the best oscillation suppression effect; detecting a turn-off signal of the GaN HEMT through a detection circuit, and outputting a trigger signal of which the length is equal to turn-off transient process time; a trigger signal is input into the driving circuit to form a low-impedance grid branch, so that the turn-off process of the GaN HEMT is accelerated; and in response to completion of turn-off of the GaN HEMT, the trigger signal is controlled to drop to a low level, an RC buffer circuit is formed, and false trigger oscillation after the device is turned off is quantitatively suppressed. According to the invention, acceleration of the turn-off process of the GaN HEMT is realized, false trigger oscillation is quantitatively suppressed, the turn-off speed of the device is not influenced, and the gate impedance is reduced in the turn-off process of the device.

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 a three-axle commercial vehicle double-stage drift control method and a safety auxiliary system for coping with extreme working conditions, and builds a double-track three-axle vehicle path tracking model containing a nonlinear tire. According to the characteristics of a curve, a steady-state drift state variable is calculated, and stability analysis is performed on a state variable root locus; based on a time-varying model prediction algorithm, an expected steady-state drift balance state is tracked, auxiliary drift control is realized, pre-look road information is obtained, a lateral error e and a heading error ΔΨ are calculated, and control modes are switched according to the two errors; when the curve is close to the end, a heading stability control integrated with active front steering and additional yaw moment is switched, so that the vehicle body posture is restored to be stable. The above obtained control instructions are transmitted to a wheel drive assembly and a steer-by-wire mechanism for real-time execution. The application realizes the fusion of curve drift and straight path, improves the deficiency that the existing method can only perform drift control in a steady-state circular working condition, and meets the drift driving demand of an unmanned commercial vehicle in a complex working condition.

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 present invention discloses a method and device for constructing a small-disturbance stability parameter safety domain for a hybrid station. The method includes: constructing an equivalent circuit diagram of the hybrid station based on the equivalent circuit of the sequence admittance model of N grid-following control power generation units and the equivalent circuit of the sequence impedance model of M grid-forming control power generation units; calculating the grid-connected current expression of the hybrid station based on the equivalent circuit diagram of the hybrid station; extracting the rate matrix of each grid-connected current component relative to the power grid in the grid-connected current expression; estimating the root locus distribution of the rate matrix, and based on preset stability judgment conditions, determining the safety domain of the first control parameter, the second control parameter, and the capacity ratio when each rate matrix meets the stability condition. The present invention can quickly and accurately determine the small-disturbance stability of a hybrid station.

The present invention provides a method and system for controlling the flow of coolant in an immersion liquid cooling system, which obtains a set temperature of the liquid cooling system, obtains a power range of a liquid cooling distribution unit and a speed range of a cooling water pump based on the set temperature of the liquid cooling system, defines a first random process based on a Monte Carlo algorithm and obtains a first random liquid cooling sample, defines a second random process based on a random forest algorithm and obtains a second random liquid cooling sample, executes a particle swarm optimization algorithm on the first random liquid cooling sample to obtain a first optimized liquid cooling control parameter, executes a random forest algorithm on the second random liquid cooling sample to obtain a second optimized liquid cooling control parameter, performs stability judgment based on a root locus diagram of a second-order transfer function of liquid cooling, and obtains an optimized liquid cooling control parameter or a fused liquid cooling control parameter; and imports the optimized liquid cooling control parameter or the fused liquid cooling control parameter into a liquid cooling control module, thereby improving the cooling effect of the immersion liquid cooling system on servers or IT equipment.

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.