11 results about "Natural coordinate system" patented technology

The application discloses a kind of model construction method and device of wind power generation system, the method wind power generation system, at least including wind turbine and permanent magnet synchronous generator, the method includes: the mechanical characteristics of wind turbine is modeled according to momentum theory data to obtain wind turbine model;Maximum power output point of wind turbine is tracked by analyzing wind turbine model and using hill climbing search method;Ideal conditions met by permanent magnet synchronous generator are obtained;Under ideal conditions, three-phase voltage equation under natural coordinate system, flux linkage equation under natural coordinate system, electromagnetic torque equation of motor, mechanical motion equation of permanent magnet synchronous generator are established to obtain permanent magnet synchronous motor model.The application can reduce the loss generated by mechanical rotation in power generation process, so that the power generation efficiency of system is higher.

The invention discloses a fault-tolerant control method and device for a high-resistance contact fault of a five-phase permanent magnet synchronous motor, and relates to the field of permanent magnet synchronous motors. The fault-tolerant control method comprises the following steps: acquiring an adjusting instruction for controlling a motor, wherein the adjusting instruction is used for indicating a target torque output by the motor; obtaining optimized reconstructed rotating orthogonal coordinate system current for the motor under different target torques; obtaining the voltage of the rotating orthogonal coordinate system according to the difference value between the current of the reconstructed rotating orthogonal coordinate system and the current of the actual rotating orthogonal coordinate system; obtaining a reconstructed rotating orthogonal coordinate system voltage according to the rotating orthogonal coordinate system voltage; and converting the voltage of the reconstructed rotating orthogonal coordinate system into a phase voltage under a natural coordinate system, inputting the phase voltage into a pulse width modulation module based on carrier waves, generating a switching signal for controlling each phase of the motor, and enabling an inverter to control the motor according to the switching signal. By means of the method, fault-tolerant control over the motor under the high-resistance contact fault is achieved, and the copper loss of the motor is reduced.

The application discloses a kind of intelligent vehicle local path planning method, device and storage medium, wherein method includes: according to positioning information and high-precision map information, the reference driving path required for intelligent car local path planning is obtained;According to the planning starting point of current planning frame is solved according to tracking effect;Smooth the reference driving path, obtain path frenet coordinate system according to the reference driving path after smoothing;Static obstacles and oncoming vehicles are projected to path frenet coordinate system, SL graph is generated, and path planning trajectory is obtained according to SL graph;Dynamic obstacle short-time prediction trajectory is projected to speed frenet coordinate system, ST graph is generated, and speed planning trajectory is obtained according to ST graph;Path planning trajectory and speed planning trajectory are coupled on natural coordinate system, and restore into high-dimensional local planning trajectory.The application uses SL graph and ST graph to process path and speed respectively, improves efficiency, and can be widely applied to trajectory planning technical field in unmanned driving.

The invention discloses a stator winding ripple current modeling and predicting method suitable for a fault asymmetric multi-phase motor system, and the method comprises the following steps: constructing an inductance matrix of a motor based on the self-inductance and inter-phase mutual inductance of each phase winding of the motor; performing elementary transformation on a motor voltage equation under a natural coordinate system based on the inductance matrix and a preset orthogonal matrix to obtain a motor voltage equation under a decoupling coordinate system, and obtaining an expression of a winding current slope based on an instantaneous voltage equation under a bridge arm open-circuit fault; on the basis of a motor voltage equation under a decoupling coordinate system and a forced constraint that a fault phase current is zero, representing a neutral point voltage of the motor as a weighted sum of a residual healthy bridge arm output voltage and mutual inductance and a rotor flux differential item; on the basis of the weighted sum expression of the output voltage and the neutral point voltage of the remaining healthy bridge arms, the instantaneous phase voltage of each phase winding is obtained through calculation; and based on the expression of the instantaneous phase voltage and the winding current slope, the ripple current of the motor is obtained through integral calculation.

The present application belongs to the field of structural deformation reconstruction, and specifically discloses a structural deformation reconstruction method and system based on a four-node inverse plate shell element containing a drilling degree of freedom, comprising: discretizing the structure into a plurality of four-node inverse plate shell elements, and constructing a shear strain matrix by using a discrete shear gap method; kinematically constraining the drilling degree of freedom by using a continuum mechanics rotation field, solving the continuum medium rotation by deriving the global coordinate system from the natural coordinate system shape function, and supplementing the sixth degree of freedom of the element around the normal line; deriving a coordinate transformation matrix based on the assigned sixth degree of freedom, introducing a node coordinate system, transforming the element stiffness matrix to the node coordinate system, and then transforming it to the global coordinate system; and finally, incorporating the above construction method into the least squares functional framework, assembling the global inverse finite element equation by minimizing the error between the theoretical strain and the measured strain, and reconstructing the full-field displacement of the structure. The present application can realize high-precision deformation reconstruction of complex stiffened plate shells and large-curvature structures.

The application discloses an equal geometry-based multi-scale topological optimization method for anisotropic periodic structure material, and comprises the following steps: (1) modeling according to an equal geometry analysis method to obtain discrete point information of a macro periodic structure and various microstructure design domains, and dividing a design subdomain for the macro periodic structure design domain; (2) constructing a coordinate conversion relationship between a natural coordinate system and a material coordinate system in an anisotropic material; (3) performing periodic material distribution optimization to determine the position of various microstructures in the macro periodic structure and the volume fraction of various microstructures by normalizing the relative density; and (4) performing periodic structure / material multi-scale parallel topological optimization to determine the macro periodic structure, various microstructures and equivalent elastic matrices thereof. The application performs multi-scale topological optimization for an anisotropic periodic structure / material based on equal geometry analysis, and is accurate, stable and efficient in convergence, and can improve the structure performance from the macro and micro scales and the structure and material angles.

The application discloses a method for extracting the fundamental back electromotive force estimation value of a permanent magnet synchronous motor under a turn-to-turn short circuit fault, and specifically comprises the following steps: transforming three-phase voltages to a rotating coordinate system to obtain the dq-axis voltage of the motor; calculating the d q-axis current according to the voltage equation and the flux linkage equation of the permanent magnet synchronous motor under the synchronous rotating coordinate system to obtain the current of the motor under the natural coordinate system, i.e. three-phase current; filtering the three-phase current and voltage after Clark transformation through a low-pass filter after inputting the current and voltage into a sliding mode observer to obtain the back electromotive force extracted based on the sliding mode observer; extracting the positive sequence component of the back electromotive force from the back electromotive force extracted based on the sliding mode observer through second-order generalized integration to obtain the effective fundamental back electromotive force, and accurate rotor position information can be estimated by using the back electromotive force. According to the method, the position of the rotor can be accurately estimated by the fundamental back electromotive force after the effective fundamental back electromotive force is extracted, and the reliable diagnosis of the turn-to-turn short circuit fault of the motor is ensured.

The application relates to an impedance-matching-based network-connection direct-drive wind power system oscillation suppression method and belongs to the field of network-connection wind power system oscillation suppression. The method comprises the following steps: building a network-side virtual synchronous machine control structure and establishing a sequence impedance model based on a static natural coordinate system; and based on the established sequence impedance model, a strategy based on impedance remodeling is constructed to suppress the oscillation of the network-connection direct-drive wind power system. The application can effectively suppress the oscillation and provides reliable technical support for safe operation of the network-connection direct-drive wind power system.

This invention belongs to the field of AC motor drive control technology, and relates to a dead-zone compensation method for permanent magnet synchronous motors based on a nonlinear flux linkage observer. The method involves measuring the induced current of the motor in the natural coordinate system and transforming it to obtain the αβ-axis current; using a nonlinear flux linkage observer in the αβ coordinate system as a position observation model to obtain the estimated actual rotor position, forming a speed loop to achieve sensorless control of the permanent magnet synchronous motor; constructing a q-axis voltage disturbance observer by measuring the phase voltage output of the inverter; using the output of the q-axis disturbance observer as the input of the dead-zone time calculation module to obtain the estimated dead-zone time; calculating and obtaining the dead-zone compensation voltage based on the estimated value to compensate the inverter output phase voltage, thus achieving dead-zone compensation. Based on the nonlinear flux linkage observer, a positionless control closed-loop structure is constructed, and the command voltage is corrected, reducing the impact of the inverter dead time on the permanent magnet synchronous motor and improving the positionless control performance.

The application discloses a kind of six-phase motor open-loop fault-tolerant control method suitable for low carrier ratio condition, belongs to motor fault-tolerant control field, and the present application is to solve the problem of single-phase open-loop fault-tolerant control method of existing six-phase motor in low carrier ratio condition Control performance deterioration, poor stability problem.The application includes: configuration fault-tolerant coordinate transformation matrix, the mathematical model of mutual inductance coupling in natural coordinate system is transformed into the mathematical model without mutual inductance coupling in synchronous rotating coordinate system, and the spatial voltage equation of mutual decoupling and linear independence is obtained;By coordinate positive transformation, fault-tolerant phase current is transformed into two spatial current components;Discrete second-order rotating decoupling controller is set in two spaces respectively, and voltage control quantity is generated;The motor is driven by phase voltage through coordinate inverse transformation.The application configures fault-tolerant current loop as discrete second-order system, and the distribution of closed-loop pole does not change with the reduction of carrier ratio, so that fault-tolerant control has good stability in low carrier ratio condition.

This invention discloses an open-circuit fault-tolerant control method for a six-phase motor suitable for low carrier ratio conditions, belonging to the field of motor fault-tolerant control. The invention addresses the problem of degraded control performance and poor stability of existing single-phase open-circuit fault-tolerant control methods for six-phase motors under low carrier ratio conditions. The invention includes: constructing a fault-tolerant coordinate transformation matrix to transform the mutually inductively coupled mathematical model in the natural coordinate system into a mathematical model without mutual inductive coupling in the synchronous rotating coordinate system, obtaining mutually decoupled and linearly independent space and space voltage equations; transforming the fault-tolerant phase current into current components in two spaces through forward coordinate transformation; setting discrete second-order rotating decoupling controllers in both spaces to generate voltage control quantities; and obtaining the phase voltage to drive the motor through inverse coordinate transformation. This invention configures the fault-tolerant current loop as a discrete second-order system, where the closed-loop pole distribution does not change with decreasing carrier ratio, thus ensuring good stability of the fault-tolerant control under low carrier ratio conditions.