21 results about "Natural coordinate system" patented technology

The application relates to the technical field of automatic driving of vehicles, and provides a vehicle obstacle avoidance trajectory planning method, a vehicle obstacle avoidance trajectory planning system, a vehicle and a storage medium.The method comprises the following steps: obtaining coordinate point information of a lane line and coordinate point information of a lane center line according to vehicle positioning information; taking the lane center line of the lane where the vehicle is located as a reference line, and converting the position, heading, speed and acceleration of the vehicle into a longitudinal position, a lateral offset, a lateral speed, a longitudinal speed, a lateral acceleration and a longitudinal acceleration in a frenet coordinate system; taking obstacle information, if there is an obstacle, converting the obstacle coordinates into S obs ,L obs , if there are multiple obstacles, converting the coordinates of each obstacle into S obsi ,L obsi , and calculating a target point through dynamic programming by means of point sampling; converting the target point into coordinates in a natural coordinate system, smoothing the coordinates through a smoothing algorithm to obtain a trajectory point set, and fitting the trajectory point set to generate a trajectory equation. The application has a simple calculation process and lower cost.

The invention discloses a dual-channel electric drive multiplexing type vehicle-mounted charging system unbalanced current suppression method, which comprises the following steps of: firstly, popularizing and applying a positive and negative sequence separation method for decoupling a dual-synchronous coordinate system to a dual-channel six-phase motor, and calculating positive and negative sequence components of a dq axis of a dual-channel system under a current unbalanced working condition; utilizing Park and VSD transformation to map the data to an alpha beta xy0102 sub-plane; secondly, setting a positive-sequence current given value and a negative-sequence current given value to be 0 by using a six-phase current distribution method for minimizing electromagnetic torque; then, independent PI control is carried out on each sub-plane; and finally, correspondingly adding the output quantities of the positive sequence current and the negative sequence current of each sub-plane, returning to a natural coordinate system through TVSD-1, and then outputting SPWM, thereby realizing a three-phase charging working condition. According to the method, the suppression of the negative-sequence current can be realized, the sine degree of the power grid current is improved, the torque ripple is suppressed, and the system safety is guaranteed.

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 single-stage multi-port motor driver power distribution control method based on modulation wave splitting. The method comprises the following steps: firstly, obtaining a three-phase reference voltage of a single-stage multi-port motor driver under a natural coordinate system; under a virtual two-level framework, carrier pulse width modulation of third harmonic injection is used to generate a three-phase duty ratio; according to the first direct current source port reference power, a zero-sequence component is obtained through calculation; injecting the calculated zero-sequence component into a three-phase duty ratio of the motor, obtaining three-phase duty ratios of a first switch tube and a second switch tube under a virtual two-level frame based on modulation wave splitting, and obtaining three-phase duty ratios of the first switch tube and the second switch tube under an actual three-level frame through normalization; and finally, comparing the three-phase duty ratio of the motor under the actual three-level framework with a carrier wave to generate a driving signal to control each bridge arm switch tube.

The invention discloses a multi-harmonic injection-based dual three-phase permanent magnet synchronous motor torque increasing method, which comprises the following steps of: establishing a mathematical model of a dual three-phase permanent magnet synchronous motor in a six-dimensional natural coordinate system, and decoupling the six-dimensional natural coordinate system into three orthogonal subspaces; in the subspace, the fifth harmonic current and the seventh harmonic current are mapped into sixth harmonic current, and a phase current model containing fundamental waves, fifth harmonic waves and seventh harmonic waves is constructed; taking a phase current peak value as a constraint, carrying out collaborative optimization on fifth and seventh harmonics by adopting a genetic algorithm, and obtaining an optimal harmonic gain coefficient by taking maximization of a fundamental current as a target; generating a harmonic current reference sequence of the future step based on the rotor position, the angular velocity, the sampling period, the rated current and the optimal harmonic gain coefficient; and establishing a discrete prediction model of the dual three-phase permanent magnet synchronous motor, and carrying out multi-step tracking on the harmonic current reference sequence by adopting generalized prediction control. According to the invention, harmonic collaborative optimization can be realized, and the dynamic tracking performance is improved.

The present application relates to the field of nuclear island civil structure design, and particularly relates to a method, system, device and medium for calculating internal force of a design section of a wallboard component, which comprises: splitting the wallboard component into multiple entity units; dividing all the entity units into multiple entity unit sets according to the thickness of the wallboard component, and constructing a local coordinate system for each entity unit set; for each entity unit of the entity unit set: identifying its intersection line and determining its design section under the local coordinate system; obtaining the coordinates of a calculation point on the intersection line under a natural coordinate system; constructing an internal force calculation model of the entity unit based on the coordinates; calculating the stress of each calculation point based on the internal force calculation model of the entity unit; and calculating the internal force of the design section based on the stress of each calculation point. The present application avoids complex graphical element operations on each entity unit, simplifies the calculation process, improves the calculation efficiency, and can improve the engineering efficiency for processing a large number of entity units.

The invention discloses a Renal scoring method and device for kidney tumors, and belongs to the field of medical image processing. The method comprises the steps that segmentation data are acquired, and the segmentation data comprise data of kidneys, tumors and blood vessels; anatomical analysis is carried out based on the segmentation data, the kidney principal axis, the renal pelvis position and the ureter are determined, and a natural coordinate system of the kidney is established; calculating the maximum diameter of the tumor based on the tumor voxel, and determining an R score according to the maximum diameter of the tumor; constructing a kidney convex hull based on the kidney parenchyma coordinates, and determining an E score based on the proportion of tumor voxels inside and outside the kidney convex hull; taking the ureter as a set system, determining the minimum distance from the tumor voxel to the set system, and determining an N score according to the minimum distance; constructing a natural interface based on the pelvis position, and determining an A score based on the natural interface; detecting polar lines based on the renal door depression, and determining an L score according to the polar lines. The method provided by the invention eliminates the subjective judgment difference of the scorer.

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 invention discloses a turn-to-turn short circuit diagnosis method for enhancing turn number estimation precision based on synchronous impedance identification, and belongs to the technical field of power generation, power transformation or power distribution. The method is specifically implemented according to the following steps: firstly, establishing a mathematical model of the permanent magnet synchronous motor under a three-phase natural coordinate system after a turn-to-turn short circuit fault occurs; then, on the basis of a parameter identification method under a static condition, current is injected twice from a healthy phase and a fault phase; then according to an equivalent circuit during two times of injection, an equivalent impedance value is solved by measured voltage and current signals; according to the relation between the equivalent impedance and the synchronous impedance, the synchronous impedance value is calculated according to the two obtained equivalent impedance values; and finally, applying the identified synchronous impedance to an existing short-circuit turn number estimation algorithm. According to the method, the identified synchronous impedance value is used for estimating the short-circuit turn ratio, so that the technical problem that the synchronous impedance value under a healthy condition cannot be obtained after the turn-to-turn short-circuit fault occurs is solved, and the problem that the identification precision is not high when the number of short-circuit turns is small is solved.

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 relates to an inclination angle compensation method, system and device for a crystallizer vibration test and a storage medium. The method comprises the steps that initial acceleration data, collected by a three-axis accelerometer of a crystallizer in a static state, of a machine body coordinate system are acquired; based on the initial acceleration data of the airframe coordinate system, constructing a rotation conversion relation from the airframe coordinate system to a natural coordinate system; in the vibration testing process, real-time acceleration data, collected by the three-axis accelerometer, of a machine body coordinate system are obtained in real time; and converting the real-time acceleration data into compensation vibration data under a natural coordinate system based on the rotation conversion relation. Through data processing such as inclination angle calculation and coordinate conversion, the inclination angle is directly compensated without manually leveling the vibration tester, so that the vibration data of the crystallizer can be obtained.

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 invention discloses a nine-phase permanent magnet synchronous motor single-phase open-phase fault-tolerant control method based on a dimensionality reduction static decoupling transformation array. The method specifically comprises the following steps: step 1, constructing a universal static decoupling transformation array of a multi-phase motor based on constant amplitude; step 2, constructing a static decoupling transformation matrix and a rotation transformation matrix based on constant amplitude when the three-neutral-point symmetric nine-phase PMSM is in normal operation; 3, representing the phase current of each phase of the symmetric nine-phase PMSM by using the components of the current coefficient and the rated current amplitude in the alpha-beta subspace; 4, taking the minimum stator copper loss as an objective function to obtain a residual phase current expression under an ML strategy after the occurrence of the single-phase open-phase fault; step 5, obtaining a transformation matrix transformed from a natural coordinate system to a rotating coordinate system after a single-phase open-phase fault; and step 6, realizing single-phase open-phase fault-tolerant control of the nine-phase permanent magnet synchronous motor. The fault-tolerant control method based on hysteresis current control solves the problems of large current ripple and uncertain switching frequency in the fault-tolerant control method based on hysteresis current control in the prior art.

The application belongs to the field of fault-tolerant control of polyphase electric machines, and relates to a permanent magnet synchronous motor open-circuit fault rotor position estimation method, which comprises the following steps: step (1), according to different open-circuit fault types, the motor mathematical model in the natural coordinate system is modified to obtain a fault motor mathematical model; step (2), according to different open-circuit fault types, a corresponding coordinate transformation matrix is established; step (3), the coordinate transformation matrix obtained in the above step (2) is used to decouple the fault motor mathematical model to obtain a fundamental mathematical model under different open-circuit fault types; and step (4), the fundamental mathematical model is used to construct a sliding mode observer to estimate rotor position information. The application realizes accurate estimation of rotor position information under motor open-circuit fault by constructing a modified sliding mode observer based on a novel fundamental mathematical model.

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.