385results about How to "Improve steady state performance" patented technology

The invention provides a cooperative control method and system of a battery energy storage power source participating in secondary frequency modulation of a power grid. The cooperative control method comprises the steps of: mounting the battery energy storage power source in a regional power grid needing the cooperation; obtaining an ACE (Area Control Error) signal from an electric grid control center by a cooperative control module; participating in the secondary frequency modulation of the power grid by the battery energy storage power source, and then dividing a typical application scene to determine the chance and participating degree of participation in the frequency modulation; converting a theoretical frequency modulation command into a practical frequency modulation command, then realizing charge/discharge control of the battery energy storage power source through an energy conversion system, and accordingly helping a traditional frequency modulation power source to finish a secondary frequency modulation process. The transient and steady performances of the secondary frequency modulation of the power grid are improved obviously, the frequent start of the traditional frequency modulation machine set is reduced, and balance between supply and demand of the power grid is maintained rapidly.

The invention provides a coordination control method capable of enabling a super-capacitor energy storage system to participate in electric power primary frequency modulation, wherein the super-capacitor energy storage system is arranged on the bus side of a generator set which needs cooperation. A decision optimizing module obtains a frequency from a synchronous vector measurement unit, and the frequency deviation is obtained through the difference between the frequency and a 50Hz frequency. If the deviation exceeds a frequency dead band, the same motion instructions are simultaneously sent to a traditional generator set and the super-capacitor energy storage system. When the super-capacitor energy storage system participates in primary frequency modulation, the opportunity motion and the motion depth of the super-capacitor energy storage system are determined through the decision optimizing module according to partition of typical working conditions, the conversion from the frequency deviation to the power is achieved through a power-frequency conversion module, the charging/discharging control of the super-capacitor energy storage system is achieved through a PCS control module, and finally the traditional generator set is assisted in participating in the primary frequency modulation process. According to the coordination control scheme, the transient state performance and the steady-state performance of the primary frequency modulation can be obviously improved, frequent starting of the traditional generator set is reduced, and the power system frequency can be rapidly kept stable.

The invention discloses a grid-connected inverter control method based on a state observer. The grid-connected inverter control method comprises the steps that (1) a bridge arm current iL1 and network voltage eg are detected, and a phase angle theta is obtained through phase locking of a phase-locked loop; (2) an observation state quantity is obtained through the state observer based on an internal model; (3) a state quantity feedback signal Xfd is obtained through a state feedback matrix K; (4) grid currents of an observational network are processed, and then grid current error signals ed and eq are obtained; (5) closed-loop processing is carried out on the grid current error signals ed and eq through a PI controller, and then through coordinate inverse transformation, wave generation voltage ui1 is obtained; (6) the wave generation voltage ui1 and the state quantity feedback signal Xfd are subtracted from each other to generate a SVPWM control signal ui of an inverter bridge switching tube, output of a three-phase full bridge inverter is controlled, and therefore a distributed power generation system is controlled to be combined to the grid. Practices show that the control method obtains good dynamic and steady-state performance for a grid-connected current.

The invention discloses a variable air volume room temperature control method based on fuzzy PID and a prediction control algorithm. The method comprises the steps that the temperature deviation between an expected room temperature and an actual room temperature is input to a fuzzy adaptive PID controller, PID parameter incremental quantity of the opening degree of a tail end air valve is obtained through calculation, and calibrated opening degree of the tail end air valve is output; the opening degree of the tail end air valve of the fuzzy adaptive PID controller is subtracted from the opening degree of the tail end air valve of a previous moment by utilizing a time delay link to obtain the variable quantity of the opening degree of the tail end air valve; the prediction control algorithm is adopted to obtain the actual opening degree of the tail end air valve through the variable quantity of the opening degree of the tail end air valve, and the room temperature is maintained at a set value and is kept unchanged. The control method combining the fuzzy PID with the prediction control algorithm is adopted to solve the technical problems that parameter setting difficulty is large, working condition adaptive capacity is poor, and adaptive ability is weak in an air conditioning system in the prior art.

The invention discloses an optimal two-vector combination-based model predictive control method and system. The method is applied to a permanent-magnet synchronous motor control system driven by a three-phase two-level inverter. A model predictive current control strategy is adopted, all two-vector combinations and resultant vector sets obtained under action time are considered at the same time, and a cost function is inspected and an optimal resultant vector is selected from all to-be-selected sets. In order to simplify the optimization process, an equivalent voltage equation is given, a sector transformation method is provided and to-be-selected two-vector combination sets are transformed into multiple fixed line segments; and a fast algorithm is given and partial complicated calculation is transformed to offline execution, so that the real-time calculated amount of the novel method is effectively reduced. The model predictive control method disclosed by the invention is simple in structure, small in real-time calculated amount and easy to implement; and the response speed of a motor is high, current ripples and distortion are small, the switching frequency is low and the dynamic and static performance of the system is excellent.

The invention discloses a maximum power point tracking control method and a system thereof of photovoltaic electrical energy optimization. The maximum power point tracking control method comprises the following steps of: step one, sampling output voltage and output current of a photovoltaic electrical energy optimized photovoltaic module to obtain the output voltage and the output current, and calculating and obtaining voltage variable quantity and current variable quantity in a default time period; step two, calculating slope of the output power to the output voltage curve based on the output voltage, the output current, the voltage variable quantity and the current variable quantity; step three, determining whether the slope is less than or equal to a default error threshold, if so, executing step four, otherwise, executing step five; step four, determining whether the mean value of the slope in the default time period equals to zero, if so, determining that the system works at the maximum power point, and returning step one; and step five, changing the value of the photovoltaic electrical energy optimized reference voltage by determining sign symbol of the slope and returning the step one.

The invention discloses a frequency stabilization control method for an alternating-current/direct-current series-parallel system, which comprises the steps of designing an under-frequency load shedding optimization model considering emergency power generation control and high-voltage direct current power support, providing an objective function giving consideration to the frequency recovery performance and the load shedding amount, selecting the action frequency of an under-frequency load shedding program and the load shedding amount of each turn as control variables, carrying out optimization on a scheme by using a cloud adaptive particle swarm algorithm containing a dimension mutation operator, and realizing intelligent control for the frequency of the alternating-current/direct-current series-parallel system. The control method disclosed by the invention solves a problem of coordination and optimization between the system instability possibly caused by frequency oscillation after the alternating-current/direct-current series-parallel system breaks down and the economy of system frequency recovery; an under-frequency load shedding scheme is optimized, an optimal setting scheme is searched intelligently, the frequency recovery performance is considered, the load shedding amount is minimized, and the transient-state performance and the steady-state performance of the alternating-current/direct-current series-parallel system are improved.

The invention discloses a novel fuzzy active disturbance rejection controller based five-phase fault-tolerant permanent magnet motor speed control method, and designs the novel fuzzy active disturbance rejection controller. A rotating speed differential value generated by a tracking differentiator and a system disturbance value observed by a linear expansion state observer are taken as the input of a fuzzy logic theory machine; and the output bandwidth value omega<c> of the fuzzy logic theory machine is taken as bandwidth input of a proportional controller. The fuzzy controller can change parameters of the controller according to the working conditions of the system in real time; the design difficulty of the controller is lowered, and the controller parameters can be adjusted in real time according to the running working conditions of the system; the novel tracking differentiator of the novel fuzzy active disturbance rejection controller ensures that the motor has no overshoot rapid response in the whole dynamic process; and compared with a conventional linear active disturbance rejection controller, the novel fuzzy active disturbance rejection controller designed in the invention has strong disturbance resisting capacity and adaptive capacity for complex working conditions, and the excellent dynamic performance.

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 discloses a short-circuit fault-tolerant vector control method for an embedded hybrid magnetic material fault-tolerant cylindrical linear motor. The short-circuit fault-tolerant vector control method comprises the following steps: building a five-phase embedded hybrid magnetic material fault-tolerant cylindrical linear motor model; compensating normal thrust missing caused by a short-circuit fault phase and suppressing a thrust ripple caused by phase short-circuit current with non-fault phase current of the motor; and obtaining expected phase voltage by adopting a series of coordinate conversion and voltage feed-forward compensation strategies, and achieving a fault-tolerant vector control after the phase short-circuit fault of the motor by a zero-sequence voltage harmonic injection-based CPWM modulation mode. According to the short-circuit fault-tolerant vector control method, the motor can suppress the thrust ripple of the motor under the condition of a phase short-circuit fault-tolerant operation; more importantly, the dynamic property, the steady-state performance and the properties in a normal state are consistent; the switching frequency of a voltage source inverter is constant; a CPU is low in overhead; and a natural coordinate system only needs to counterclockwise rotate a certain angle in any phase short-circuit fault, so that the motor fault-tolerant operation can be achieved.

The invention discloses a one-phase open-circuit fault-tolerant direct thrust control method for a five-phase permanent magnet linear motor. Firstly, a Clark transform matrix and an inverse matrix thereof are derived based on fault-tolerant phase current. On the above basis, a stator flux linkage on alpha-beta is derived, a stator virtual flux linkage is defined according to the requirements of acircular stator flux linkage trajectory, and thus the voltage compensation on alpha-beta is derived. The stator actual voltage on the alpha-beta is derived by a modulation function of a voltage sourceinverter, and voltage is combined with voltage compensation and stator current, and a stator virtual flux linkage and thrust are observed by a stator flux observer and a thrust observer. Then statorvirtual target votlage is calculated according to given thrust, a given stator flux linkage amplitude and the observed stator virtual flux linkage and thrust. Finally, the stator actual voltage is calculated by the voltage and the voltage compensation, and the motor is controlled by the voltage by the voltage source inverter. According to the method, a thrust fluctuation caused by a motor failureis suppressed, and more importantly, the dynamic performance and steady state performance are consistent with that in a normal condition.

The invention relates to a parametrization design method of an anti-disturbance composite servo controller. The parametrization design method is that damp of a closed loop system pole is dynamically changed to synthesize the quick response performance of a low-damp system and a low-overshoot characteristic of a high-damp system, accordingly quick and stable fixed-point tracking is achieved. The controller consists of a conventional linear feedback control law serving as a first portion and used for ensuring the system stability so as to enable a closed loop system to have high response speed, a non-linear feedback control law serving as a second portion and used for enabling a controlled system to quickly and stably track a set point, and a third portion for merging disturbance and uncertainty factors of the system to form an extension state variable and meanwhile estimating a non-measurement state and unknown disturbance of the system through a reduced order extension state observer and used for state feedback and disturbance compensation. By adopting the method, quick, stable and accurate servo tracking of a target position under various load conditions is achieved.

The invention relates to an electrified railway in-phase power supply device and a multi-target coordinated instantaneous current control method adopted by the device. After the in-phase power supply device is used, the electrified railway whole-line in-phase power supply can be realized, the output power of two power supply arms of a traction transformer can be balanced, and the negative sequence problem can be thoroughly solved; the load reactive power and the harmonic current can be compensated, and the electric energy quality of a traction power supply system can be comprehensively improved; the voltage of a traction electric network can be stabilized, the transient state stability of the voltage can be improved, the power supply distance of the power supply arms can be increased, and the amount of power substations can be reduced; the electrified railway in-phase power supply device and the multi-target coordinated instantaneous current control method are multiple in targets, the multi-target can be simultaneously controlled, the control harmony at two sides can be guaranteed, the dynamic response capability is stronger; a rectification side inverter takes the active power transfer and the stable direct voltage as a control target, and participates the reactive power control; and an inversion side inverter performs active power, reactive power and harmonic wave control, and participates the stable control of the direct voltage.

The invention relates to an electromagnetic sensing heating device and a method thereof. The electromagnetic sensing heating device comprises a microprocessor, a modulation circuit, a driving circuit, an insulated gate bipolar transistor (IGBT) half-bridge circuit, a main oscillation circuit and a synchronizer circuit, wherein the input end of the modulation circuit is connected with an input/output (I/O) port of the output end of the microprocessor, and the output end of the modulation circuit is connected with the driving circuit; the output end of the driving circuit is connected with the control end of the IGBT half-bridge circuit; the output end of the IGBT half-bridge circuit is connected with the control end of the main oscillation circuit; and the input end of the synchronizer circuit is connected with the main oscillation circuit in serial, and the output end of the synchronizer circuit is connected with the driving circuit. The heating efficiency of the heating device is higher than that of a traditional half-bridge circuit. The improved half-bridge circuit is connected with an inversion circuit in serial, so the cost of a full-bridge circuit is greatly reduced. A control strategy combining a constant-power temperature control method and a temperature control method is adopted, so good transient-state performance and good stable performance can be realized, and higher precision and higher reaction sensitivity can be realized.

The invention discloses a piezoelectric ceramic actuator hysteretic model. The piezoelectric ceramic actuator hysteretic model comprises an error conversion module (1), a self-adaptive control module (2), a piezoelectric ceramic actuator hysteretic module (3) and a dynamic system module (4), wherein the error conversion module (1) is used for outputting z1(t) to the self-adaptive control module (2); the self-adaptive control module (2) is used for outputting v(t) to the piezoelectric ceramic actuator hysteretic module (3); the piezoelectric ceramic actuator hysteretic module (3) is used for outputting u(t) to the dynamic system module (4); the dynamic system module (4) is used for outputting y(t); a difference value e(t) is obtained by carrying out subtraction on the y(t) which is actually output by the dynamic system module (4) and yd(t) which is expected to be output through a subtracter (5); z(t) can be obtained by carrying out conversion on the difference value e(t) through the error conversion module (1).

The invention provides an improved Smith estimator-based H-infinity control method of an aero engine, and belongs to the technical field of aero engine control and simulation. The improved Smith estimator-based H-infinity control method comprises the steps of building a reasonable small deviation linear model for an aero engine non-linear model, and selecting data of a state space model in a certain working condition as a controlled object designed by a controller; selecting an appropriate performance index weighting function parameter, solving an H-infinity output feedback controller, and adjusting the parameter to basically achieve control requirement; and designing an improved-structure Smith estimation compensator according to a closed-loop feedback control system designed according toan H-infinity control law so as to form a composite controller, additionally arranging a deviation correction controller, designed according to a PID control law, in the control system according to relatively large deviation between an estimation model and the parameter of the controlled object and a true model and the parameter, employing the deviation correction controller to stabilize the controlled object, making adaptability correction according to comparison between the controlled object and a model output signal so as to further improve robustness of the system.

An adaptive control method for a robotic arm servo system based on a time-varying asymmetric obstacle Lyapunov function comprises the following steps of step 1, establishing a mathematical model of the robotic arm servo system, and designing the time-varying asymmetric obstacle Lyapunov function; step 2, designing an adaptive controller by using the time-varying asymmetric obstacle Lyapunov function and combining an inversion method; and step 3, analyzing stability. By setting the parameter value of a constraint boundary function, the adaptive control method provided by the invention can effectively solve the system output constraint problem and ensure the steady-state performance and transient performance of the system. In addition, the uncertain part of a neural network approximation model and the derivative of the virtual control quantity are used to effectively simplify the design of the controller, improve the robustness of the system to a certain extent, and enable the robotic arm servo system to achieve accurate and fast tracking control.

The invention discloses an apparatus and a method for detecting harmonic current. Voltage and current signals measured by a sensor enters a sampling maintaining A/D converting circuit through an anti-aliasing filtering circuit; a lock phase loop synchronization pulse generating circuit provides a conversion signal for the sampling maintaining A/D converting circuit; a digital signal processor uses an LMS/LMF self-adaptive harmonic current detection algorithm to detect a harmonic current value in load current; a keyboard circuit and a colorful liquid crystal display realize a man-machine conversation; and a ferroelectric storage stores data. The invention uses the improved LMS/LMF algorithm to update weight and uses the self-correlation estimation of the normalized prior error signal and the last error signal during a step-size iteration, thereby effectively avoiding the influence caused by a lower signal-to-noise ratio and obtaining the better stable effect. The invention uses a TMS320F2812 chip to realize on the specific algorithm; a DSP program is easy to operate to continuously detect signals to be detected for a long time; and the hardware circuit of the whole apparatus is simple, small and convenient to carry and store data.

The invention discloses an anti-interference method of a satellite navigation receiver. The method includes: firstly, setting an array for lineup; receiving signals through an array antenna and processing the signals; conducting delay processing to the signals; obtaining a reference channel and a surplus reception channel; setting a weight parameter for filtering; conducting error estimation to obtain an error parameter; selecting a step length factor for weight updating; repeating until an algorithm enters a steady state convergence point to obtain a weight of the steady state convergence point; utilizing the weight to filter the signals so as to obtain the signals after anti-interference; sending digital signals after anti-interference processing to a rear-end for processing, or sending the digital signals to a DA (digital to analog) converter to be converted to analog signals for outputting. The anti-interference method of the satellite navigation receiver is small in calculation amount, is favorable for a project to be realized, and is small in data processing capacity, and fine in instantaneity, steady state and anti-interference effect.

The invention discloses a second-order-odd-repetitive-controller-based odd harmonic current suppression method of a magnetic levitation rotor. A magnetic levitation rotor kinetic model including rotor mass unbalance and sensor harmonic is established; and a second-order-odd-repetitive-controller(SOORC)-based odd harmonic current suppression method of a magnetic levitation rotor is employed. The SOORC has a second-order inner membrane structure for odd harmonic frequency suppression, so that the harmonic suppression capability on a harmonic frequency changing or uncertain condition can be improved and thus the control robustness of the system for the harmonic frequency changing or uncertain condition can be improved. With phase hysteresis-lead compensation, the steady performance and dynamic performance of the system are improved, so that odd harmonic current components generated by a magnetic bearing coil in a magnetic levitation rotor can be suppressed. The method is suitable for suppression of odd harmonic current components of the magnetic levitation rotor system with rotor mass unbalance and sensor harmonic.

The invention relates to a method and a system for controlling a battery energy storage power station for primary frequency modulation of a power grid. The method comprises the steps of determining the frequency modulation requirement of the power grid according to the frequency deviation change rate of the power grid; determining the energy demand of the battery energy storage power station according to the battery charge information of the battery energy storage power station; and adjusting the frequency modulation power of the battery energy storage power station based on the power grid frequency modulation requirement and the energy demand of the battery energy storage power station. According to the method, the rapid response characteristic of the battery energy storage power stationis utilized, and fast response and rapid recovery are carried out on the frequency change of the power grid, so that the steady-state performance of primary frequency modulation is improved; and meanwhile, the battery energy state of the battery energy storage power station is optimized, so that the battery energy storage power station has the capability of primary frequency modulation for a longtime, and the transient performance of primary frequency modulation is improved.

The invention relates to a solar charging system, a device and a method for tracking a maximum power point thereof. In the method, first-side regulation comprises: performing first change on the output voltage of a current solar battery array and carrying out second-side regulation if the power after the first change is judged to be lower than that before the first change; or setting current dutycycle as the duty cycle of a maximum power point and repeating first-side regulation if the power after the first change is judged to be not lower than that before the first change; and the second-side regulation comprises: performing second change on the output voltage of the current solar battery array and carrying out the first-side regulation if the power after the second change is judged to be lower than that before the second change; or setting the current duty cycle as the duty cycle of the maximum power point and repeating second-side regulation if the power after the second change isjudged to be not lower than that before the second change. The technical scheme of the invention has good steady-state performance and dynamic performance of tracking the maximum power point.