101 results about "Fuzzy pi" patented technology

The invention discloses a digital electric valve positioner and a method thereof. The positioner consists of a control unit, an I / P electric conversion unit, a valve position feedback unit and a malfunction diagnosis unit. By the configuration of the flux characteristic parameters of the positioner, the working flux characteristic aberration which is caused by the factors such as a change of the pressure drop ratio of the adjusting valve, etc. is corrected, which is based on that a plurality of flux characteristics and action directions of the adjusting valve integration are provided. The control to the valve position of the adjusting valve is based on a Fuzzy-PI dual-mode no-interference shifting algorithm. Depending on the internal relationship between the valve position given value, the valve position feedback value and the valve film head pressure which are arranged by a control center and applying a rule-based knowledge reasoning, the malfunction diagnosis is realized through that the user selects to release or partly release the valve film head pressure during the stuck freeing operation. The valve displacement / electric conversion of the valve position feedback unit depends on a non-contact magnetic sensitive potentiometer. The man-machine interaction adopts a touch screen technique, and the control unit is accessed in a control network by an Ethernet interface.

This invention discloses a dual-feed AC-DC-AC converter control structure for wind power generation, and the rotor exciting magnetic converter using the fuzzy PI adaptive control strategy of current inner loop. When the generator no-load networking, the current inner loop uses the conventional PI regulator, and after networking, as to three modes, sub-synchronization, synchronization, super-synchronous, it uses fuzzy adaptive PI control. The network-side converter uses SPWM control strategy which fixed switching frequency and combining electric network electromotive front-feed. In the invention, both converting processes use four-quadrant operation PWM converters based on full-controlled devices, so it can not only improve the system dynamic response, reduce wastage and impact, achieve the two-way electric transmission, but also it can achieve wind power generation network side unit power factor sinusoidal current networking power generation operating.

The invention discloses a method for controlling a grid-connected inverter of a micro grid based on the fuzzy PI algorithm. The method comprises the steps that (1) the voltage of the current power grid, the output current of the current grid-connected inverter and the capacitive current of a current filter are sampled; (2) the command value of a grid-connected current is determined; (3) the proportionality coefficient and the integral coefficient of a PI controller are adjusted; (4) the command value of the capacitive current of the filter is acquired through the adjusted PI controller; (5) the command value of the output voltage of the grid-connected inverter is acquired through the PI controller; (6) a control signal is generated to control switch-on or switch-off of a switching tube of the grid-connected inverter, and an expected output voltage is generated at the power output end of the grid-connected inverter; (7) the step (1) to the step (6) are repeatedly executed to make the output current of the grid-connected inverter trace the command values all the time. According to the method, by adjusting the control parameter of the PI controller in an on-line mode through the fuzzy algorithm, the output current of the grid-connected inverter can trace a current command signal quickly and accurately.

A control method for a high-voltage direct-current flexible system for supplying power to a passive network includes: arranging a rectifier controller at the head end of a direct-current transmission line of the high-voltage direct-current flexible system, performing constant direct-current voltage control for a VSC (voltage source converter)-rectifier on the alternating-current system side, arranging a VSC-inverter controller at the tail end of the direct-current transmission line, and performing constant direct-current voltage control for the a VSC-inverter. A double closed-loop vector control policy is used for VSC-rectifier constant direct-current voltage control, fuzzy PI (proportional integral) control is used for an outer voltage loop, and current decoupling control is used for an inner voltage loop, so that active power and reactive power are controlled independently. The method avoids complicated offline parameter adjustment of a traditional PI adjustor and is capable of performing online PI parameter adjustment according to changes of the system running state and high in adaptive adjustment capability, the system is higher in response speed and control precision for various interferences and failures, and anti-interference capability and dynamic and steady-state performances of the system are improved.

The invention relates to an online adjustment method for a PI (proportion integrate) parameter of an asynchronous motor, the method comprises the following steps of formulating a control rule table for changing values of parameters P and I according to certain principle; judging a current operation state of the motor according to an operating speed of the motor; adopting a conventional PI control when the motor operates at a stable speed; when the motor operates at an accelerating speed or a reducing speed, adopting a fuzzy PI control to carry out an online self-adjustment for the PI parameter until the motor operates in a stable state, the self-adjustment comprises that according to a distribution scope of a rotation speed deviation value e and the value of a changing rate ec of the rotation speed deviation, a domain and scale coefficients Ke and Kec of e and ec are defined to obtain a novel control rule table; setting an initial value for the PI parameter; and carrying out the online self-adjustment for the PI parameter. By the adoption of a fuzzy self-adaptive PI control method, the PI parameter is adjusted to enable the current PI parameter to always meet the requirement of current working condition, the reaction time can be accelerated by utilizing the method to adjust the PI parameter, and dynamic performance of the motor is improved.

The invention discloses a high-precision permanent magnetic servo motor three-closed-loop control system and a high-precision permanent magnetic servo motor three-closed-loop control method. The system comprises an upper computer, a control module, a detection driving module and a power module; the power module comprises a three-phase inverter and a permanent magnetic synchronous motor; three phases of outputs of the three-phase inverter are connected to the interior of the permanent magnetic synchronous motor; a software part comprises a position control module, a speed control module, a current control module and a voltage vector modulation module and is controlled by adopting a three-closed loop system comprising a position loop, a speed loop and a current loop; a speed error signal is regulated by fuzzy PI compound control of the control module; the fuzzy PI (Proportion Integration) compound control comprises fuzzy control and PI control which are combined by adopting a fuzzy conversion mode; and the voltage vector modulation module is a voltage vector pulse width modulation module on the basis of a Kohonen neural network. According to the invention, the dynamic performance, the steady accuracy and the robustness of a permanent magnetic synchronous motor controller can be effectively improved and the control rapidness and strong load disturbance resistance are achieved.

The invention discloses a self-adaptive fuzzy control method for an active power filter based on feedback linearization, relates to the technical field of an active power filter, and respectively designs independent self-adaptive controllers aiming at a current loop and a voltage loop. As the current loop adopts the self-adaptive fuzzy controller for the active power filter based on the feedback linearization, the feedback linearization theory, fuzzy control, sliding mode control, self-adaptive control and Lyapunov stability theory are comprehensively utilized, and on the basis of ensuring the global stability, the purpose of harmonic compensation is realized. As the voltage loop adopts the self-adaptive fuzzy PI (process integration) control, according to the fuzzy rule, the control strategy can automatically adjust the PI parameter, strengthen the robustness of the system, improve the dynamic performance of the system, and ensure the tracing to the command voltage.

The invention discloses a frequency tracking system for output signals of an ultrasonic power supply based on a fuzzy PI control technology, which is composed of a hardware circuit and software programs, wherein the hardware circuit includes a voltage and current sampling circuit, a band-pass filtering circuit, a phase discrimination circuit, an STM32 chip, an IGBT driving circuit and a display screen connected with the STM32 chip, the phase discrimination circuit collects the phase difference between voltage and current and realizes a digital phase-locked loop, the fuzzy PI control technologyis implemented in the form of the software programs, the software programs are executed by the STM32 chip, the main control program includes a system initialization program, a display screen program,a phase difference information capturing program and a PWM frequency control output program, and the PWM frequency control output program includes a PWM output program and a fuzzy PI algorithm program. The frequency tracking system disclosed by the invention can enable the frequency of the output signals of the ultrasonic power supply to change along with the resonant frequency of a transducer, thereby achieving automatic, accurate and fast tracking for the resonant frequency of the transducer.

The invention discloses an active filter current self-adaptive control method based on fuzzy PI composite control, and the method not only utilizes the advantage that fuzzy control does not depend on system parameters but also utilizes the capability of self-adaptive control of overcoming the uncertainty of a controlled object as well as the quick and precise tracking performance of the self-adaptive control to compensate for modeling errors and external disturbance on line in real time, so that compensation current quickly and accurately tracks a command current signal while capacitive voltage on a direct current side precisely tracks the set voltage, the purpose of eliminating harmonic wave is achieved, the compensation performance of an active power filter and the robust performance of the system can be greatly improved, the control goals of quickness and high adaptability are achieved, and the quick popularization of the active power filter is facilitated.

The invention discloses a brushless direct-current motor fuzzy PI controller based on FPGA, belongs to the technical field of motor control and aims to solve the problems that according to the existing brushless direct-current motor adopts a fuzzy adaptive PID algorithm to control the motor, and the control of the motor is delayed since the executing speed is low. A filter module filters and transmits Holzer position signals to a speed calculation module; the speed calculation module calculates to acquire the motor speed feedback signals in real time; a speed fuzzy PI adjusting module calculates to acquire current adjusting determined signals; a current PI adjusting module adopts the traditional PI algorithm to modulate the current of the motor to acquire and transmit PWM modulation signals to a PWM modulation and commutation module; the PWM modulation and commutation module transmits commutation signals and PWM modulation signals to a power drive module to drive a brushless direct-current motor. The controller is applied to control of the brushless direct-current motor.

The invention discloses a control optimization method for a wind power-thermal power-stored power combined frequency modulation system. The method comprises the steps of (S1) building a thermal power unit frequency modulation response model and a power storage system frequency modulation response model participating in frequency modulation, and analyzing and determining the frequency modulation characteristics of a frequency modulation thermal power unit and a power storage system in the system; (S2) carrying out spectrum analysis on output power of a wind power plant and controlling stored power-assisted thermal power participating in the frequency modulation; (S3) building a fuzzy PI control strategy of taking a control deviation ACE of two regional systems and the variation thereof as control inputs; and (S4) building a control strategy of the wind power-thermal power-stored power combined frequency modulation system on the basis of a control strategy of the stored power-assisted thermal power participating in the frequency modulation and the fuzzy PI control strategy. Meanwhile, the invention discloses the wind power-thermal power-stored power combined frequency modulation system, so that coordinated operation of the thermal power and the stored power can be ensured; an analysis basis and a calculation basis are provided for operation control of a wind power-thermal power-stored power system; and the control strategy for coordinated operation of the stored power and the thermal power unit is designed.

The invention discloses a sliding-mode control method for fuzzy PI parameter self-turning feedback linearization of an active filter. By a fuzzy PI parameter self-turning feedback linearization method, according to actual error in voltage control of the direct-current side of the active filter, fuzzy reasoning is performed according to a preset fuzzy rule so as to realize self-adaptive regulation of feedback linearization control law parameters, and accordingly, stability and adaptability of the voltage of the direct-current side are improved effectively. An integral position tracking sliding-mode controller is capable of effectively reducing harmonic content of supply current after compensation and improving harmonic compensation effect of the active filter. Further, since a synchronous coordinate transformation based unit sinusoidal-signal computing method is utilized, unit synchronous sinusoidal-signals can be computed accurately on the condition of high harmonics of supply voltage, and can be used for computing of reference supply current. The sliding-mode control method has the advantages that the harmonic compensation effect is good, the voltage of the direct-current side of the system has good dynamic and static characteristics, and system performance keeps good even when the power supply contains the harmonic voltage and non-linear loads change.

The invention relates to the technical field of signal processing and application of mass flow meters based on the Coriolis principle, in particular to a method for designing a Coriolis mass flow meter digital drive system. The method includes the steps that firstly, according to the characteristics of a Coriolis mass flow meter, a fuzzy PI amplitude control algorithm is designed; secondly, the fuzzy PI amplitude control algorithm is applied to the Coriolis mass flow meter digital drive system, and then a measurement tube can rapidly vibrate at the fixed amplitude when different fluids are measured under different measurement environments. According to the method, the fuzzy PI control algorithm is added based on an existing nonlinear amplitude control algorithm, a frequency estimation algorithm based on zero-cross detection is adopted, a whole control system is more intelligent and more flexible, a software and hardware test system of the Coriolis mass flow meter digital drive system based on a DSP is designed, and therefore the measurement tube of the Coriolis mass flow meter can rapidly vibrate at the fixed amplitude.

The invention discloses a semi-active control method of an energy reclaiming type semi-active suspension system. The semi-active control method is characterized by obtaining an ideal electromagnetic damping force Fref required to be output by a linear motor through a skyhook and groudhook suspension damping semi-active control strategy; dividing the ideal electromagnetic damping force Fref by an electromagnetic damping coefficient ki, thus obtaining a needed reference current iref; collecting a real current value ireal in a motor winding through a current sensor; inputting a difference value e of the reference current iref and the real current value ireal and a difference value change rate ec into a fuzzy-PI (Proportion Integration) mixed controller; outputting two paths of pulse signals by the fuzzy-PI mixed controller to control the switching on and off of an MOS (Metal Oxide Semiconductor) transistor in a semi-active control circuit, thus realizing semi-active control.

The invention provides a control method for actively suppressing power grid harmonics. A harmonic component can be precisely detected and separated by adopting a harmonic current detection method based on transient reactive power; in order to achieve a better output current control effect than the conventional proportion and integration (PI) control effect, a composite control strategy, in which fuzzy PI closed loop adjustment is taken as a core, is determined; therefore, online adjustment and optimization of PI parameters are realized; and the harmonics of a harmonic load and a device to a power grid are suppressed effectively.

In order to solve the problem that the speed following performance of an upright vehicle is not good due to solving the conflict between speed control and upright control of the upright vehicle, the invention provides a method for controlling an upright vehicle based on fuzzy PI. In the design of a fuzzy PI controller, the states of the upright vehicle under different working conditions are analyzed. A setting principle of fuzzy PI control parameters capable of enabling the system to obtain optimal response performance is formulated, software simulation is carried out on the upright vehicle adopting fuzzy PI control, and a real vehicle test is carried out. Test simulation results show that the upright vehicle speed following performance based on the fuzzy algorithm is good, the stability and the robustness of the system are high.

The invention provides a novel fuzzy PI double-loop control method based on stratification thoughts and a software and hardware scheme which is implemented by the method through a TMS320F2812DSP. According to the control method, a fuzzy control method is combined with a traditional linear PI voltage / current double-loop control method to form a closed-loop system according to the fuzzy control theory, and a boost convertor with given parameters serves as an embodiment for simulation verification. The simulation result shows that the dynamic performance and the static performance of the system can be greatly improved through the control method, protection can be achieved to the maximum degree, and the control design that the speed is as high as possible but does not exceed a protection limiting value is achieved. Besides overcurrent protection, special input inrush current limitation is further set, so that startup surge is retrained to the maximum extent, and power diodes for the startup surge are saved. The complexity and computation of the control algorithm with regard to stratification of input variables are decreased, and therefore the fuzzy PI double-loop control method provides possible thinking for flexibly achieving more additional control functions.

The invention discloses an active filter auto-disturbance rejection control method based on fuzzy PI compound control, which comprises that a mathematic dynamic model of an active filter is established; based on the mathematic dynamic model, the fuzzy PI compound control is used to control a direct current capacitor voltage, and an active current of a main circuit of the active electric filter is input by an output power grid; according to the active current, an auto-disturbance rejection controller is used to work out a control law; and the control law is input into a PWM controller to generate a signal which controls an inverter to be switched on or switched off, a switching tube in the main circuit is controlled, and an alternating current compensation current is generated and injected into the power grid to realize current compensation and idle elimination. The active filter auto-disturbance rejection control method based on the fuzzy PI compound control disclosed by the invention can ensure real-time tracking of an instruction current by the compensation current and can effectively reduce harmonic waves.

The invention relates to a fuzzy PI control method and device for variable propeller pitch of a wind generating set. The method comprises the following steps: a PI controller is used for controlling a propeller pitch angle of the wind generating set according to a deviation signal; and a fuzzy controller is used for regulating parameters of the PI controller. The method can effectively solve the time lag problem and the controlled object nonlinear problem in viable propeller pitch control of a fan, and improves adaptive capacity, to a complex working condition, of the controller.

The invention discloses an active filter control method based on fuzzy PI and repetitive control. On the basis of parallel cooperative operation of a fuzzy adaptive PI controller and a repetitive controller, a dynamic response speed and steady state response precision of the active filter can be effectively guaranteed. The fuzzy adaptive PI controller uses a fuzzy control principle to carry out on-line adaptive setting on a PI parameter and characteristics of high fuzzy control robustness and fast PI control response speed are fully combined, thereby realizing the rapid shock-free response function of the controller. According to the internal model principle of the repetitive controller, internal model construction of the periodic harmonic current reference signal and amplitude phase compensation of the control object are carried out, thereby realizing the no-steady-state-error tracking function of the controller. According to the invention, with integration of advantages of the fuzzy PI controller and the repetitive controller, the active filter can be operated safely, stably, and effectively.

The invention relates to a brushless DC motor simulation control method and a brushless DC motor simulation system. The brushless DC motor simulation control method comprises steps that S1, back electromotive force in a BLDCM body is acquired; S2, a PI controller is used to establish a speed control module; S3, a Hall signal generating module is established; S4, a reference current module and a current hysteresis control module are established; S5, an inversion circuit module is established. On basis of analysis of brushless DC motor mathematic model, by combining with conventional PI control and fuzzy control advantages, fuzzy PI control and current hysteresis control are used for a permanent magnet brushless DC motor double-closed loop control system used for an electric vehicle, and then simulation verification of a control strategy is carried out, and therefore the rotation speed response of the DC brushless motor is fast and overshoot-free, and strong inhibition performance related to load disturbance is provided, good dynamic, static characteristics are provided, and then the acceleration performance and the driving stability of the electric vehicle are improved.

The invention discloses a power generation system based on a cylindrical linear oscillation motor, comprises a free piston Stirling engine, a cylindrical linear oscillation motor, a rectifier bridge circuit, a position sensor, a central controller, a battery pack, wherein the position sensor comprises a mover position detection module based on a linear Hall sensor, and the central controller adopts three closed loops control; The three closed-loop control adopts the voltage loop of parameter self-tuning fuzzy PI control and the current loop of speed loop and decoupling control of position-freedetection algorithm combined with PI regulating space vector. A linear oscillation motor, Position Sensorless Technology, based on voltage, the three closed loop control method of speed and current controller is combined and applied to the power generation system, Ensure power quality, improve the dynamic response speed and robustness of the power generation system, at the same time use sensorless technology to solve the position sensor on the environment and installation accuracy requirements of high problems, reduce the manufacturing cost of the power generation system and installation difficulty.

The invention discloses a fuzzy-PI control based active equalization control method for a lithium battery, and relates to the technical field of a lithium battery. The control method comprises the steps of 1) detecting the charging-discharging current signal of a series-wound battery pack and the end voltage of each single battery, and estimating the SOC (state of charge) value of each single battery by a UKF algorithm; 2) setting that the battery pack consists of n single batteries connected in series, the SOC average value of the battery pack is a formula which is as shown in the specification, and the SOC difference value of the single batteries is a formula which is as shown in the specification; when <delta>SOC is greater than or equal to the set value, starting a fuzzy controller, wherein the fuzzy controller takes the average value which is a formula as shown in the specification and the difference value <delta>SOC as the input, carries out fuzzy calculation on the average value which is a formula as shown in the specification and the difference value <delta>SOC to obtain an accurate equalizing current maximum value Imax, and outputs the Imax to a PI controller and then to a controlled object through an execution unit. The problems of long equalization time, waste of energy, shortened service life when high electric energy utilization ratio is achieved, impossibility of ensuring equalization efficiency and precision, and unstable equalization judgment exiting in the current lithium battery equalization method can be solved by the fuzzy-PI control based active equalization control method.

The invention discloses a fuzzy PI control-based aviation generator voltage regulation method. In a voltage regulation process, deviation between an adjustment point feedback voltage and a reference voltage is detected, and deviation differential is solved; a fuzzy rule table is divided into four regions according to the deviation and the deviation differential; and four processes of increasing and decreasing the adjustment point voltage are performed corresponding to loading and de-loading conditions of the four regions respectively; and different parameters are set for the four regions to set PI parameters in the loading and de-loading conditions separately. By virtue of the method, the shortcoming that voltage adjustment parameters cannot be set separately in different load change conditions in the original method is overcome.

The invention discloses an adaptive order fractional order fuzzy PI lambda controller method. The method specifically includes the following steps that 1, three control parameters of a fractional order PI lambda controller are determined aiming at controlled object GP; 2, a fuzzy rule and a subordinating degree function are set up based on the fuzzy set theory, and a set-up fuzzy controller is added into the fractional order PI lambda controller and used for correcting the parameters; 3, the fractional order controller corrected by the fuzzy controller is connected into a control system, the fuzzy controller corrects the parameters of the PI lambda controller in real time according to input, and a needed control effect is achieved. The adaptive order fractional order fuzzy PI lambda controller method is high in response speed and small in overshoot, and has good robustness for disturbance.

The invention discloses an island microgrid operation method based on fuzzy PI control. The method comprises the steps of establishing an island microgrid operation model, wherein an island grid comprises master distributed generation and slave distributed generation; improving a droop controller in a v / f droop control system based on fuzzy PI; controlling operation of the master distributed generation through the droop controller, thereby obtaining voltage amplitude and frequency output by the master distributed generation; and converting the voltage amplitude and frequency into modulation signals and controlling the output power of an inverter of the master distributed generation according to the modulation signals. The fuzzy PI control is added to the droop controller in the v / f droop control system; on the basis of fuzzy reasoning, the droop controller can effectively control the voltage amplitude and frequency output by the master distributed generation; the output voltage amplitude and frequency are converted into the modulation signals; the output power of the master distributed generation can be effectively controlled according to the modulation signals; and the fluctuation of the voltage amplitude and frequency in the operation of the island microgrid can be further inhibited.

The invention discloses a zero reactive power control method for a permanent magnet synchronous motor. The method comprises five parts: motor speed loop closing, a distribution method of alternating and current shaft currents, double loop closing of alternating and current shaft currents, feedforward decoupling of alternating and current shaft voltages and space vector modulation. The vector amplitudes of the alternating and current shaft currents of the motor are given by means of a motor speed ring, the alternating and current shaft currents demands are distributed by means of the distribution method of alternating and current shaft currents, and tracing of a given value on the actual current of the motor by the double loop closing of alternating and current shaft currents is ensured, sothat the aims of meeting the load demands by the active power of the permanent magnet synchronous motor and zero reactive power are achieved. Zero reactive power operation of the permanent magnet synchronous motor is achieved, the loss of the reactive power of a power grid is reduced, the voltage quality of the power grid is improved, and the method has important meaning in national economic development. A speed adjustor and a current adjustor are a PI adjustor, a PID adjustor, a fuzzy PI adjustor, a fuzzy PID adjustor, a slide film adjustor or a neural network adjustor.

The invention discloses a photovoltaic MPPT control method based on fuzzy PI two-way linear prediction. The method includes the following steps that first, a power-voltage characteristic curve of a photovoltaic cell is obtained, two-way linear prediction is performed through the tangent line of the characteristic curve to approach the maximum power point, and the approximate maximum power point is obtained through calculation; second, on the basis of the approximate maximum power point, the actual maximum power point is tracked with a perturbation and observation method, and the error e(k) and the error conversion delta e(k) are calculated, wherein delta e(k)= e(k)- e(k-1), the k represents the period, P represents the power, and u represents the voltage; third, the error e(k) and the error conversion delta e(k) serve as input of a fuzzy controller, the Mamdani fuzzy reasoning method is adopted for the fuzzy controller, a fuzzy control rule is established with the target that the output power can fast reach a given value, and maximum power point tracking is achieved. The method effectively solves the problem that the tracking speed and the calculating precision can not be taken into consideration at the same time with a traditional MPPT control method, the maximum power point can be tracked fast and accurately, and the method is simple and practical.

The invention provides a speed regulating system of a switch reluctance machine. The input end of a direct instantaneous torque controller receives a given rotating speed; a state error is solved according to the input given rotating speed and a fed back actual rotating speed; a fuzzy PI rotating speed regulator performs composite control algorithm processing through fuzzy control and PI regulation; by virtue of addition of an integral item, steady-state error of the system can be eliminated effectively, and the stable operation of the whole speed regulating system can be maintained; and on the basis of the direct instantaneous torque fuzzy PI regulation and control, automatic regulation of an opening angle is added, and by constantly regulating the changing and phase commutating process of the opening angle, current peak can be restrained, thereby improving operating efficiency of the motor.

The invention relates to a power grid simulator control system and method based on fuzzy PI and QPR. The system comprises a DC power module, an inversion module, a filter and a load which are connected in sequence. The control end of the inversion module is connected to the output end of a control module, and the input end of the control module is connected with the filter and the load. The control module performs voltage control based on the voltage outer loop fuzzy PI and performs current control based on the current inner loop QPR so as to modulate and output a switch control signal to the inversion module. The inversion module inverts the direct current output by the DC power module according to the switch control signal, and outputs to obtain an alternating current fault test waveform. Compared with the prior art, PI control parameter optimization can be autonomously performed according to the change of the system so that the system is enabled to always operate in the optimal state, output of the required waveform can be achieved, and the system and the method have the advantages of being high in anti-interference capability, high in response speed and great in stability.