260 results about "Static error" patented technology

Systems and methods are provided for performing static error analysis on source code. A computer system having an operating system may contain a number of source code files. During a normal build process, a build program may be used to set various compilation options and to invoke appropriate compilers that compile the source code files into executable code. Static analysis debugging tools may be used to perform static analysis on the source code files. The appropriate static analysis tools may be invoked using a static analysis tool management program. Directory, path and name modification may be used to invoke the analysis tools. A monitoring program may be used to determine how to invoke the tools. The operating system may be modified so that the static analysis tools are invoked in place of the compilers when the build program is run.

The invention discloses a method and a device for adjusting the rotating speed of an inner fan of an air conditioner. The adjusting method is used for adjusting the rotating speed of the inner fan by means of a PI algorithm via a P parameter and an I parameter according to a difference value between the practical rotating speed and the target rotating speed of the inner fan. In the process of adjusting the rotating speed of the inner fan, the method comprises the following steps: detecting the practical rotating speed of the inner fan; calculating the rotating speed difference of the inner fan, wherein the rotating speed difference is the difference between the practical rotating speed and the target rotating speed; correcting the I parameter and / or the P parameter according to the rotating speed difference; and adjusting the rotating speed difference of the inner fan by means of the PI algorithm via a corrected parameter according to the rotating speed difference. Due to the adoption of the method and the device, the rotating speed response of an indoor motor is quick, the static errors and dynamic overshoot are lowered, high anti-interference performance is achieved, the aim of mute drive is fulfilled, and the comfort of the air conditioner is improved.

The invention discloses a frequency control method and control device of a compressor of an air conditioner. The method comprises the following steps: when the temperature difference between the actual temperature of the room in which the air conditioner is positioned and the set temperature of the air conditioner is greater than the preset value, firstly controlling the compressor to work at a first frequency until the temperature difference is equal to the preset temperature value; then controlling the compressor to work at a second frequency until the temperature difference is equal to 0 DEG C; when the temperature difference is equal to 0 DEG C and the room load is not changed, controlling the frequency of the compressor according to the intervention algorithm; when the temperature difference is equal to 0 DEG C and the room load is changed, modifying the working frequency of the compressor according to the intervention algorithm and the incremental PID algorithm; and when the temperature difference is not greater than the preset value, directly controlling the frequency of the compressor according to the incremental PID algorithm. In the invention, different control algorithms are used for adjusting the frequency of the compressor according to different temperature difference, thereby effectively reducing overshoot control, furthest eliminating control static error and realizing the purpose of simply, quickly and stably adjusting temperature.

The invention provides a grid power quality control system and method based on a unified power quality conditioner. The system comprises a series MMC, a parallel MMC and a control circuit. The series MMC and the parallel MMC form a unified power quality conditioner (UPQC) topological structure based on MMC, and are connected to a grid side and a load side through a transformer respectively. The method comprises the following steps: carrying out transformation on an MMC module under an abc stationary coordinate system to obtain a differential equation matrix model under a dq rotating coordinate system; obtaining small-signal models of the series MMC and the parallel MMC under the dq rotating coordinate system; utilizing the parallel MMC to output an offset current and stabilize DC side voltage; and utilizing the series MMC to output an offset voltage. A fundamental wave positive sequence voltage component and a fundamental wave positive sequence current component adopt a PI regulator, and other components adopt a PR regulator to realize non-static-error control, so that compensation is carried out not only for the cases of distortion, harmonic wave and reactive power and the like, but also for the cases of unbalance power source voltage and unbalance load, and the load is allowed to obtain reliable power supply.

The invention discloses a current prediction control method and apparatus for a permanent magnet synchronous motor (PMSM). The method comprises the steps: acquiring the motor stator current and stator voltage under two-phase rotating coordinates; constructing a current and perturbation sliding-mode observer, and predicting and obtaining the motor stator current and the parameter perturbation estimated value of the next moment; according to the principle that the practical current value of the next moment is equal to a current command value, obtaining a PMSM current prediction control expression; taking the current value, predicted by the observer, of the next beat, as current feedback, and obtaining the command voltage of a motor driver through calculation; and further adding the command voltage and the parameter perturbation estimated by the observer together, taking the sum as the final motor driver command voltage, and finally generating a pulse signal for controlling motion of a switch tube through an SVPWM device. The current prediction control method for a permanent magnet synchronous motor can predict the current of the next beat and estimate parameter perturbation at the same time, and can effectively restrain the current tracking static error and reduce the motor harmonic wave current and optimize the current control performance when a parameter mismatching problem exists.

The invention discloses a control method of a PID controller by combining multiple control algorithms. The existing PID control method has the following defects: as for integral, integral accumulation, which causes PID operation, results in integral saturation, causing great over modulation of the system; and as for differential, differential is especially sensitive to interference, and frequent fluctuations of the given value can result in system oscillation. The invention is characterized by comprising the following steps: carrying out scale operation on the amount of deviation to obtain the output value of a proportional part; carrying out variable speed integral operation on the amount of deviation, and then carrying out trapezoidal integral operation to obtain the output value of an integral part; carrying out incomplete differential operation on the amount of deviation to obtain the output value of a differential part, thereby obtaining the output value of PID; carrying out output amplitude limiting operation; and finally, carrying out output rate limiting operation. On the premise of maintaining integral, eliminating static error of and enhancing precision, the invention reduces the over modulation amount; and the invention eliminates the external interference to some extent and eliminates oscillation caused by frequent motions.

The invention provides a method for recognizing and standardizing parameters of a quartz flexible accelerometer measuring assembly. The technical proposal is as follows: a static error of the quartz flexible accelerometer measuring assembly is excited by controlling a triaxial position speed rotating floor to different positions, the dynamic error of the quartz flexible accelerometer measuring assembly is excited by controlling the triaxial position speed rotating floor to rotate at different speeds, a Kalman filter is adopted to recognize an error model parameter of the quartz flexible accelerometer measuring assembly, and an error model of the quartz flexible accelerometer measuring assembly is determined by adopting the recognized parameter. The technical proposal has positive effects on improving the standard accuracy of the quartz flexible accelerometer measuring assembly, thereby improving the accuracy of a strapdown inertial navigation system provided with the quartz flexible accelerometer measuring assembly.

The invention discloses a mobile terminal base station differential positioning method. The method comprises the steps that a positioning device acquires one or more pieces of base station differential information matching a positioning request from a base station differential information database; the signal propagation time from a mobile terminal to a number of base stations, the signal propagation time difference of a number of base stations, or the signal intensity correction value of each base station is calculated; the positioning device uses the correction value to respectively correct each parameter; and the positioning device calculates the positioning information of the mobile terminal according to the corrected parameters. According to the mobile terminal base station differential positioning method, the positioning device and the system, which are provided by the invention, the multi base station information of one or more known positions is used to carry out differential correction on the multi base station information of an unknown position; a static error caused by dynamic errors of base station signal drift and the like and antenna feeder length and the like is eliminated; the positioning accuracy is improved; and a common terminal can be used to automatically collect differential data, which is convenient for implementation.

The invention relates to a suspension control method for a magnetic suspension system, which comprises the steps: adopting a current loop to accelerate the rising velocity of the current i in an electromagnetic coil; adjusting a position loop to control the suspension performance in a set range; eliminating the static error during stable suspension by controlling the integral of a suspension clearance; selecting an integral control parameter ki so as to eliminate the influence of the suspension clearance integral on suspension performance; using a suspension performance index to adjust a suspension clearance control parameter kp and a suspension clearance differential control parameter kd; determining laden variable quantity according to the variation of stable suspension current i; corresponding changes the suspension control parameters kp and kd according to the variation of suspension current i0 so as to adjust the voltage control variable u2 at the both ends of an electromagnet in the suspension process and keeping the suspension performance unchanged all the time under the condition of variable load. By using the current of the magnetic suspension system when the suspension is stable to change the suspension control parameters, the method can not only overcome the disadvantages of the ordinary PID control method, but also has the advantage of easy realization of the ordinary PID control method.

The invention discloses a repetitive-control-based method for controlling a compensation current of a DSTATCOM (Distribution Static Synchronous Compensator). The method comprises the following steps of: (1) acquiring a grid voltage, a load current and the compensation current; (2) extracting current commands from the load current; and (3) carrying out repetitive control and PI (Proportional-Integral) control according to the current commands, and then, outputting voltage commands to the DSTATCOM. According to the repetitive-control-based method for controlling the compensation current of the DSTATCOM, the no-static-error tracking of the low-order harmonics, comprising fundamental harmonics, of the DSTATCOM can be achieved, the compensation accuracy of the DSTATCOM is improved, the compensation bandwidth of the DSTATCOM is increased, and the compensation capability and accuracy of the DSTATCOM with unbalanced loads are improved, so that the DSTATCOM can have harmonic compensation and suppression capabilities, the use of passive filters at the outlet side of the DSTATCOM is reduced, the harmonic performance of the compensation current of the DSTATCOM is improved, the harmonic output is reduced, and the pollution to a power grid is reduced.

The invention discloses a dynamic calibration method of an electric automobile lithium ion battery SOC. The method includes the following steps that an OCV-SOC list is obtained and stored through an open circuit voltage method, and vehicle standing threshold time is preset; if vehicle standing time is longer than the threshold time, the current single voltage of a vehicle is obtained, and if the vehicle standing time is shorter than or equal to the threshold time, a battery management system does not act; and the battery management system searches the OCV-SOC list according to the current single voltage for an SOC value needing to be calibrated, the current SOC value and the SOC value obtained through the search of the list are recorded, the SOC deviation between the current SOC value andthe SOC value obtained through the search of the list is calculated, and the battery management system uses an SOC algorithm with dynamic calibration for conducting dynamic calibration on the batterySOC. By the adoption of the dynamic calibration method of the SOC, the SOC deviation is recorded and not calibrated in the vehicle standing process according to the battery single voltage, a static error is complemented to the battery SOC in proportion in the vehicle operation process, the SOC jumping change caused by SOC static calibration is avoided, the client misunderstanding that large powerconsumption or electric quantity counterfeit happens in the vehicle standing process is avoided, and the method is only achieved through a software algorithm of the battery management system.

The invention relates to a control method of a grid-connected inverter of a large-scale grid-connected photovoltaic power station. The control method is characterized by comprising the following steps: establishing a grid-connected inverter model under a d-q coordinate system; realizing active and passive power decoupling control by adopting a state feedback exact linearization nonlinearity control strategy; and eliminating static control errors generated by inaccurate system parameter estimation by utilizing cascaded PI (Proportion Integration) adjustment. By utilizing the method of the invention, modeling and grid-connected dynamic analysis are carried out on the grid-connected inverter of the large-scale grid-connected photovoltaic power station to fully reflect the validity of the control method under the conditions of considering different power factors, intensities of illumination, faults, and the like. Compared with a traditional control method, the control method disclosed by the invention is scientific, simple to adjust parameters, can eliminate static errors and has the advantages of favorable dynamic characteristics, stronger robustness, strong suitability, high practical application values, and the like.

The invention discloses a variable-ship-length-rate-based crosswind-resistant straight path tracking method of an unmanned surface vessel. In view of different influences on path tracking by different ship length rates, a variable-ship-length-rate-based straight path tracking method is put forward based on combination with fuzzy control. The range deviation and a changing rate of the range deviation are used as inputs of a fuzzy controller and the ship length rate is used as the output of the fuzzy controller; the ship length rate is adjusted dynamically, thereby adjusting a course angle to adjust LOS-principle-based input and output parameters of a PD controller of a tracking expected course angle alpha fai. Voltages of motors at the left side and the right side of the unmanned surface vessel are controlled, thereby realizing straight path tracking of the unmanned surface vessel in a water-surface crosswind environment. Besides, with a course correction and error compensation method, static error occurrence caused by path tracking in a crosswind environment is reduced and a straight path tracking effect of the unmanned surface vessel in an anti-interference environment is improved.

The invention relates to an improved droop control based microgrid auxiliary master-slave control method. The method is used for maintaining stability of the voltage and power of the microgrid. The microgrid comprises multiple DGs connected with alternating current buses respectively; each DG comprises a master-control DG, an auxiliary DG and a slave-control DG; the master-control DG and the slave-control DG are used as a master-control unit and a slave-control unit in the master-slave control method respectively; the inverter in the auxiliary DG adopts voltage and current dual-loop control; a load current io is multiplied by a dynamic virtual impedance Zvir, and the obtained product is used as an instruction voltage to be added in a feedback signal to a voltage loop, so that the output impedance of the inverter is sensitive. Compared with the prior art, the inverter of the auxiliary DG adopts the dynamic virtual impedance, so that matching between the output impedance of the inverter and the circuit impedance can be ensured, voltage drop can be effectively relieved, and the power quality is ensured; and in addition, the improved droop control is adopted, and an integral link is introduced in the reactive power control link, so that steady state voltage without static errors is realized, and the steady state performance of the system is improved.

The invention relates to a motor speed regulation control algorithm, in particular to a BP (back-propagation) neural network PID speed regulation control algorithm based on fuzzy control. The BP neural network PID speed regulation control algorithm based on fuzzy control is designed in order to solve the problems of static difference and low convergence rate of a traditional dual closed-loop DC speed regulation system based on BP neural network PID control. The BP neural network PID speed regulation control algorithm based on the fuzzy control comprises steps as follows: firstly, the structureof a BP network is determined, input and output of each layer of the network are calculated, then output of a controller is calculated with an incremental PID control algorithm, parameters of the PIDcontroller are adjusted online in real time according to self-learning ability of the BP network, the optimal PID control parameter is obtained, static errors of the system are eliminated by the aidof the fuzzy control, and accordingly, adjustment of the rotating speed of the DC motor is realized. The BP neural network PID speed regulation control algorithm has beneficial effects as follows: theBP neural network PID controlled DC motor speed regulation system based on the fuzzy control can eliminate the static errors, the convergence speed is high, and good static and dynamic performance, anti-interference performance and robust performance are achieved.

A resolver detected position compensation system for a resolver is provided that can enhance a position detection precision by performing a further compensation on a compensated position that was obtained from a static error compensation. The position detection circuit outputs a compensated detected position signal in which a static error has been compensated. The differential circuit differentiates the compensated detected position signal to obtain a rotational speed of the resolver. Based on a signal representing the rotational speed output from the differential circuit, the phase data memory device and the peak value memory device send the variation in phase and the amplitude peak value, respectively, of the dynamic error signal to the multiplication device. The multiplication device calculates an estimated dynamic error and the subtraction circuit removes the estimated dynamic error from the compensated detected position signal.

The invention discloses a dead-beat control system and a method for a permanent magnet synchronous motor with complex vector modeling in a discrete domain, which is characterized in that the system comprises a permanent magnet synchronous motor, an encoder, an abc-dq coordinate conversion unit, a speed outer loop PI controller, a current dead-beat controller, a dq-Alphabeta coordinate conversion unit, an SVPWM modulation module, and an inverter. The invention has the beneficial effects that: in the modeling process of the current prediction model, the inverter and the motor are regarded as a whole modeling, the delay action of the inverter is considered, and the established model is more accurate than the traditional current prediction model; a current error integral compensation module isadded to the dead-beat controller, the stator current control static error is greatly improved, and finally the purpose of no-beat control at low switching frequency is achieved. The results show that the motor speed and stator current are well controlled, the motor stator current control static error is small, and the output torque ripple is also improved.

The invention provides an LOD model generation method based on a linear quadtree. The method comprises the following steps: performing linear quadtree segmentation on to-be-drawn terrain, storing data of the to-be-drawn terrain in a two-dimensional array, reading information of each node in the linear quadtree from the two-dimensional array through an index, storing leaf node information of the linear quadtree, organizing terrain nodes, enabling the terrain nodes in the linear quadtree to be stored in a one-dimensional array, establishing a terrain node evaluation mechanism on the basis that a static error and a dynamic error are considered, performing crack elimination on different segmentation levels of the adjacent terrain nodes, and obtaining an LOD model based on the linear quadtree. The method is applied to a terrain simplification aspect in a computer graphics and image field, and the terrain nodes are organized by utilizing a linear quadtree storage model and through combination use of a two-dimensional filling curve; on the basis that error factors are fully considered, the node evaluation mechanism is established, and a terrain crack problem is eliminated; and terrain drawing efficiency can be obviously improved.

The invention discloses an MEMS inertial navigation system and a track reconstruction method based on the same. A six-position method is applied to error factor identification on a gyroscope and an accelerometer, a static error model is obtained, and therefore static errors are compensated; the random error of the gyroscope and the accelerometer is remarkably reduced through filtering of a low pass filter, noise is lowered, and output precision is improved. A complementary filter algorithm is adopted for effectively combining the updated attitude angles of the gyroscope and the accelerometer to obtain an attitude matrix. The attitude matrix is used for acceleration conversion and gravity compensation, and then the triaxial acceleration of a navigation module in an inertial coordinate system is obtained. Finally, track and speed information is obtained through iterative dual integration. The independently solved attitude angles of the accelerometer and the gyroscope are combined through the complementary filter algorithm, divergency of drifting of the attitude angles can be restrained, and attitude calculation is greatly improved in a dynamic state and a static state.

The invention discloses an LOE (loss of excitation) fault tolerance prediction control method and device for a permanent magnet synchronous motor, and the method comprises the steps: obtaining the rotating speed, voltage and current of the permanent magnet synchronous motor, designing an LOE torque detection sliding-mode observer, obtaining an LOE disturbance estimation value and the observation value of the rotating speed, carrying out the fault tolerance prediction and rotating speed control to calculate a q-axis instruction current, designing an LOE flux linkage detection sliding-mode observer, obtaining a current observation value and a state current observation value after the LOE of a permanent magnet, carrying out the fault tolerance prediction and rotating speed control to calculate an instruction voltage, carrying out the inverse Park transformation and modulation through an SVPWM module, and generating a PWM pulse signal. The device comprises program units corresponding to the steps. The method achieves the quick and no-static-error tracking of the rotating speed and current of the permanent magnet synchronous motor under the LOE condition of the permanent magnet, optimizes the control performances of a rotating speed ring and a current ring, and facilitates the application of the permanent magnet synchronous motor in a severe environment and occasions with higher requirements for reliability.

The invention relates to a sequence arranging method for a current source switch array of a digital-analog converter, and the switch array comprises (2n)2 current source switches arranged in the (2n) multiplied by (2n) array from, wherein n is an even number; and the sequence arranging method comprises the one-dimensional direction arranging step and the two-dimensional direction arranging step, wherein the one-dimensional direction arranging step is as follows: arranging the sequence of the 2n current source switches in each rack according to the hierarchical symmetrical switch sequence. The current source switch array adopting the sequence arranging method can effectively inhibit gradient error and symmetry error, namely reduce static error of the digital-analog converter and further ensure the high precision of the digital-analog converter.

The invention discloses an optimal position calibration method of a static drifting zero and primary acceleration related term error model of a flexible gyroscope, which acquires an optimal test position by adopting a D-optimal test design method. In the invention, the output of the flexible gyroscope is effectively improved by carrying out measured value compensation on acquired optimal space quadrature-12 position drifting coefficients and an acquired flexible gyro static error compensation model G0 under the optimal space quadrature-12 position; the drifting coefficients are acquired by respectively adopting a traditional 8-position method, a full-space quadrature-24 position method and an optimal space quadrature-12 position method in the flexible gyro test process in an inertial navigation center; and the residual square sum of gyro testing values can shows that a solved result of the drifting coefficients after being compensated by utilizing the optimal space quadrature-12 position test design method of the flexible gyroscope is improved by 4 to 5 times compared with the traditional 8-position method, the precision is improved and the test time is shortened by half compared with the full-space quadrate-24 position test method.

A resolver detected position compensation system for a resolver is provided that can enhance a position detection precision by performing a further compensation on a compensated position that was obtained from a static error compensation. The position detection circuit 5 outputs a compensated detected position signal in which a static error has been compensated. The differential circuit 11 differentiates the compensated detected position signal to obtain a rotational speed of the resolver. Based on a signal representing the rotational speed output from the differential circuit 11, the phase data memory means 15 and the peak value memory means 17 send the variation in phase and the amplitude peak value, respectively, of the dynamic error signal to the multiplication means 19. The multiplication means 19 calculates an estimated dynamic error and the subtraction circuit 21 removes the estimated dynamic error from the compensated detected position signal.

The invention provides an unbalance compensation method for a three-level static synchronous compensator (STATCOM), belonging to the technical field of reactive compensation for power systems. The method comprises the following steps of: detecting an asymmetrical current at a load side under the conditions of unbalanced power gird and asymmetrical load, and carrying out sequence decomposition; respectively carrying out dq transformation on the obtained positive and negative sequence currents to obtain DC references, and realizing the complete decoupling of positive and negative sequence active and reactive currents by using PI decoupling control to obtain the positive and negative sequence reference voltage vector of a three-level STATCOM output voltage; and finally, carrying out simplified three-level SVPWM (Space Vector Pulse Width Modulation) to obtain PWM (Pulse Width Modulation) driving signals to control the action of a switch device to produce a required compensation current. The invention overcomes the influence of the unbalanced power grid and the asymmetrical load on the performance of the three-level STATCOM, the reactive current and the negative sequence current under the conditions of unbalanced power gird and asymmetrical load can be accurately compensated, the stable balance of capacitance and voltage at a DC side is maintained, and the unbalance compensation method has the advantages of quick dynamic response and no static errors.

The invention discloses a permanent magnet synchronous motor simulator considering nonlinear characteristics and a control method thereof. The method includes the steps of outputting three-phase voltages and currents, and obtaining q-axis and d-axis voltage and current components respectively through coordinate transformation and combined with a current cycle electrical angle; obtaining q-axis andd-axis counter electromotive force (EMF) components; establishing a nonlinear permanent magnet synchronous motor mathematical model, taking the q-axis and d-axis voltages and q-axis and d-axis counter EMF as the input to calculate the mechanical angular velocity, electrical angle, motor rotation speed, and q-axis and d-axis currents of a next cycle, and taking the q-axis and d-axis currents as command currents for the closed-loop control of the next cycle; and regulating differences between the command currents and the q-axis and d-axis current components by using a current regulator, and connecting the reference voltage obtained after the inverse Park transformation of the results to an SVPWM modulation module such that a three-phase full-bridge converter actually outputs the command currents. According to the invention, the operation characteristics of various working conditions under the condition of non-linear counter EMF can be effectively simulated, and the tracking without static error of high frequency signals contained in the higher harmonic currents can be achieved.

The invention discloses a bidirectional AC / DC converter parallel system control method for a DC microgrid, and the method comprises the steps: secondary ripple inhibition, low-voltage deviation current-sharing control and voltage and current double-closed-loop control. Through the introduction of a second-order band-stop filter, the method achieves the effective filtering of the secondary ripple components in the current and voltage of the DC grid, and prevents the feedback introduced to a control loop from causing the grid-connected current distortion. The mean current of a DC line is fed back as a global variable in the low-voltage deviation current-sharing control, and an integration link is introduced, thereby achieving the precise distribution of power of each converter without the impact from the line parameters. The deviation of a DC bus voltage is reduced through the introduction of the mean output voltage PI (Proportional-Integral) control. A voltage outer loop in the voltage and current double-closed-loop control employs PI control, thereby guaranteeing the no-static-error tracking of a DC voltage. A current inner loop employs quasi-proportional resonant control, thereby achieving the better tracking control of a fundamental wave sine current.

The invention discloses an orthogonal filter-based inverter non AC voltage sensor control method. The method comprises steps: a second-order generalized integrator is firstly used for constructing an orthogonal filter according to no difference following characteristics of specific-frequency AC signals; the orthogonal filter is then used for constructing a voltage observer of a three-phase grid-connected inverter, in a two-phase stationary coordinate system, grid side current signals obtained after measurement and voltage reference signals at an inverter controller output bridge end serve as input of the voltage observer for carrying out observation on the grid voltage; and in combination with PR control of the three-phase grid-connected inverter in the two-phase stationary coordinate system, operation control on the inverter in the condition of non AC voltage sensor can be realized. Due to the method, in the condition of ensuring control stability of the inverter, integral saturation, initial value sensitivity, static error and other problems possibly appearing during the conventional non AC voltage sensor control can be avoided, and the method has the advantages of being quick, free of static errors and insensitive to the initial value.

The invention discloses a square wave compensation control method for the operating range of an enlarged cascaded H-bridge photovoltaic inverter and belongs to the field of photovoltaic power generation. The method mainly comprises the following steps of (1) independently controlling the direct-current-side capacitor voltage of each H-bridge unit and obtaining the active power instruction value ofa grid-connected current; (2) realizing the static-error-free control of the grid-connected current, and simultaneously generating the total modulating voltage of the inverter and the modulation degrees of all H-bridge units; (3) according to the square wave compensation strategy, calculating the modulation wave of each H-bridge module. Compared with published documents in the prior art, the normal operation of the power factor of an inverter unit is ensured when the input power of the cascaded H-bridge photovoltaic grid-connected inverter is not balanced seriously. Meanwhile, the fluctuation of the direct-current-side capacitor voltage of the enlarged cascaded H-bridge photovoltaic inverter is ensured to be small.

Disclosed is an attitude angular velocity measuring method based on a magnetic-suspension inertia actuator. On the basis of modeling of an attitude measuring system for an active magnetic bearing, influence of a displacement stiffness item in bearing force on attitude measurement of angular velocity is considered, a dynamic coupling and static compensation network design method for two-axis attitude angular velocities, which are acquired by measuring, for dynamic coupling and static error between the two-axis angular velocities of a spacecraft. The attitude angular velocity measuring method is simple and practical, the attitude measuring system based on the active magnetic bearing has high capacity of tracing attitude angular velocities of the spacecraft, high-precision attitude angular velocities of the spacecraft are achieved, and foundation for integration of attitude measurement and attitude control of the magnetic-suspension inertia actuator is laid.

The invention relates to a method for controlling harmonic currents in a synchronous rotating reference frame by several times. Compensated harmonic currents at a certain time are converted to the synchronous rotating reference frame with the same times of rotating speeds and directions, harmonic instruction current information of an SFR is fully utilized, AC disturbance quantity brought by other nonsynchronous current components in the SFR is removed through a simple algorithm, so that the DC quantity corresponding to the compensated currents at the time in the SFR is extracted, and PI static-error-free decoupling control is achieved. The stability margin and the dynamic response speed of a control system can be effectively improved, and the steady state errors of the system are removed.