42results about How to "Reduce Harmonic Distortion" patented technology

The invention discloses an emergency power supply quick access method based on scene recognition, which relates to the technical field of emergency power supplies, and comprises the following steps: in an emergency power supply system, firstly obtaining electrical input parameter information through a preset detection frequency; by introducing a load change evaluation mechanism based on machine learning, the system can identify load fluctuation in real time and dynamically adjust the detection frequency, and the response speed to the rapid change of the load is improved. Compared with a traditional detection method, the load state is intelligently evaluated and accurately divided, it is ensured that the power factor is adjusted in time when the load fluctuates violently, and power loss and waste are reduced. Correction is carried out according to the traditional frequency during stable load fluctuation, the frequency is dynamically adjusted during rapid fluctuation, the electric energy use is optimized, the electric power quality is improved, and harmonic distortion and overload risks are reduced.

The invention provides a voltage amplifier and a preparation method thereof, which can be applied to the technical field of voltage amplifiers. The voltage amplifier method includes: a noise matching transformer including a primary winding, a secondary winding, and a magnetic core, the noise matching transformer being configured with a target number of turns of the primary winding and a target number of turns of the secondary winding, thereby reducing noise of the active amplifier, the target number of turns of the primary winding is determined according to at least one of the first number of turns and the second number of turns, the target number of turns of the secondary winding is determined according to the signal source resistance, the resistance of the primary winding and the single-turn average resistance of the secondary winding, and the primary winding comprises a first tap and a second tap, the secondary winding comprises a positive tap, a negative tap and a center tap; the active amplifier is used for amplifying the signal source voltage according to the gain of the active amplifier, and the gain of the active amplifier is determined according to the target number of turns of the primary winding and the target number of turns of the secondary winding.

The invention discloses a parametric array loudspeaker nonlinear distortion modeling and compensation method based on deep learning. The method comprises the following specific steps: (1) recording an audio sound signal output by a parametric array loudspeaker system and an input signal of the audio sound signal at a listening position where nonlinear distortion needs to be suppressed, and making a data set for modeling; (2) performing overall modeling on the parametric array loudspeaker system by using a neural network F, and training the neural network F by using the data set; modeling a linear part of the system by using an FIR (Finite Impulse Response) filter model Flin; (3) using the trained neural network F and the model Flin to train a neural network G as an inverse filter of the system; and (4) preprocessing an audio signal expected to be replayed through the neural network G, and inputting the preprocessed audio signal into a parametric array loudspeaker system to realize nonlinear compensation of the system. According to the method, accurate modeling and effective compensation can be carried out on the nonlinear distortion of the parametric array loudspeaker, and the nonlinear distortion of the parametric array loudspeaker is remarkably inhibited.

The embodiment of the invention provides a multi-channel transcranial focused ultrasound regulation and control system and method based on high-frequency precise-control SPWM (Sinusoidal Pulse Width Modulation). The system is applied to the technical field of ultrasonic treatment and comprises a main control module, an ultrasonic driving module, a frequency tracking module, a power supply module and an ultrasonic transducer, the master control module is used for SPWM signal generation, driving strategy switching and frequency tracking algorithm deployment. The ultrasonic driving module is used for receiving the SPWM signal output by the main control module, amplifying and filtering the SPWM signal and then outputting a target sine driving signal to the ultrasonic transducer; and the frequency tracking module is used for realizing real-time detection and tracking of the actual resonant frequency of the transducer. According to the invention, the hardware cost of multi-channel driving is reduced; the total harmonic distortion of the driving signal is reduced, and the frequency and phase control precision is improved; multi-channel driving is realized through a single MCU, and cortical and deep brain region regulation and control are compatible; the stability of the treatment process is guaranteed while the energy utilization efficiency is improved.

A sinusoidal modulation circuit for driving LEDs on optical analysis instruments includes: a sinusoidal voltage, a conversion circuit structure, a voltage follower, a bypass capacitor, and a light-emitting diode (LED). The sinusoidal voltage is connected to the conversion circuit structure, the voltage follower is connected to the conversion circuit structure, the bypass capacitor is connected to both the conversion circuit structure and the voltage follower, and the LED is connected to both the conversion circuit structure and the voltage follower. The conversion circuit structure includes: resistors R1, R2, R3, and R5, capacitors C1 and C2, and a power operational amplifier. Compared with traditional technologies, this invention reduces total harmonic distortion (THD), eliminates the need to adjust circuit hardware parameters when driving multiple LED loads, simplifies the circuit design, and achieves the function of driving LEDs with a sinusoidal current source at a lower cost.

The utility model is suitable for the technical field of electronic circuits, and provides a dimming circuit of a multi-section light emitting diode and lighting equipment, the circuit comprises a power supply output circuit, a whole-section light emitting diode LED, an LED dimming circuit and an LED constant-current driving circuit, the power supply output circuit is connected with the whole-section LED comprising a plurality of sub-section LEDs and used for providing power for the whole-section LED, and the LED dimming circuit is connected with the LED constant-current driving circuit. Outputting a line network voltage value; the LED dimming circuit is respectively connected with the power supply output circuit and the whole section of LED and is used for sampling the network voltage value and the whole section of voltage difference value of the whole section of LED and respectively outputting a silicon controlled rectifier control signal value and a dimming voltage value; and the LED constant-current driving circuit is respectively connected with the LED dimming circuit, each sub-segment LED and the power supply output circuit, and is used for providing constant current for each sub-segment LED according to the dimming voltage value and determining to open or close a silicon controlled discharge circuit in the LED constant-current driving circuit according to the silicon controlled control signal value. Therefore, the linearity of low-luminance dimming is effectively improved.

The application relates to a hybrid AC / DC microgrid based on a reconfigurable modular multilevel converter and an operation method and a storage medium thereof. The microgrid comprises a modular multilevel converter (MMC), the MMC comprises a plurality of phase legs, each phase leg comprises an upper arm and a lower arm, each arm is connected with a plurality of sub-modules in series, each sub-module comprises a semiconductor switching device, a capacitor energy storage unit and a controllable bypass switch structure; the MMC is connected with an AC bus and a DC bus respectively to realize bidirectional power conversion. The system comprises a plurality of feeder branches which are connected with the bus through power switching devices. Distributed edge controllers are arranged at the sub-modules or feeder interfaces to collect voltage and current parameters and output isolation or bypass signals in an abnormal condition; meanwhile, hierarchical reconfiguration controllers are arranged to perform structure reconfiguration and power path redistribution. The application realizes fault rapid isolation and reconfiguration cooperation through hierarchical control, maintains the voltage stability of the key load bus, and realizes the effect of improving the system reliability and power supply continuity.

The utility model discloses a controllable direct current brushless motor driving module which comprises a power supply assembly, a three-phase PWM control assembly and a PFC assembly. A driving assembly; the driving assembly comprises a rectification circuit, a PFC, a power supply, an MCU FU6812, a three-phase sine driver, a three-phase AC permanent magnet motor, a signal isolation circuit and a UART communication interface. The rectification circuit is electrically connected with the PFC, the PFC is electrically connected with the power supply, the power supply is electrically connected with the MCU FU6812, the three-phase sine drive is electrically connected with the MCU FU6812, and the three-phase AC permanent magnet motor is electrically connected with the three-phase sine drive. The problems that in an existing fresh air system and an existing dust-free workshop, a plurality of fans are installed inside, a plurality of motors are needed for driving control, more electric energy is consumed when the motors work at the same time, the energy efficiency of the whole dust-free workshop is possibly reduced, each motor needs to be maintained and overhauled regularly, and the working efficiency of the whole dust-free workshop is affected are solved. And a plurality of motors mean the problems of higher maintenance cost and more complicated maintenance work.

The invention discloses an attention learning mechanism-based inverter model control prediction method, system and device, and a storage medium, and the method comprises the steps: pre-constructing a three-phase inverter simulation model, carrying out the real-time sampling of a state signal through employing an MPC controller, and obtaining a signal characteristic set; performing feature selection on the signal feature set, and extracting feature data; setting a screening threshold to screen the feature data, and taking the screened feature data as optimal features; inputting the optimal feature into a pre-trained machine learning model module to obtain a prediction result of the control signal of the three-phase inverter; the control performance can be improved while more calculation amount and communication traffic are reduced.

A current decoupling control method for an auxiliary inductor dual-buck half-bridge power amplifier relates to the field of precision motor drive. The present invention controls the magnitude of the average current flowing through the auxiliary inductor to balance the current passing through the filter inductors on the two branches, thereby reducing the output current pulsation and further reducing the loss. The magnitudes of the currents in the two branches are set to constant values, so that the two branch currents output a half-cycle sine wave, and the branch output current does not pass through the zero point, thereby reducing the switching loss and harmonic distortion. The topological method of auxiliary increase in inductance can reduce the total inductance volume of the loop, and improve the problem of large inductance volume and weight caused by the DC bias magnetization of the inductor caused by the bias current. In addition, the auxiliary inductor current is added to the bias current of the loop, thereby reducing the nonlinear distortion of the system. The present invention improves the disadvantage of large inductance volume in the traditional dual-buck half-bridge inverter circuit loop, reduces the cost, and reduces the harmonic distortion of the circuit.

The invention provides a sigma-delta modulator and a switched capacitor integrator, which are applied to the technical field of integrated circuits and sigma-delta modulators, a sampling capacitor and an integrating capacitor respectively form a new parallel structure capacitor by two new capacitors, and in the parallel structure, the sampling capacitor and the integrating capacitor are connected in parallel. The sum of the capacitance values of the two new capacitors corresponds to the capacitance value of the original sampling capacitor (or the integrating capacitor), and the top plates and the bottom plates of the two new capacitors are connected in a staggered manner. By improving the capacitor into a new parallel structure, the charge transfer error can be reduced by utilizing the transfer characteristic of charges in the capacitor in the parallel structure, so that the linearity of the capacitor is remarkably improved, and finally, the linearity of the integrator and the modulator can be improved.

The invention discloses a sound production device and electronic equipment, and relates to the technical field of electroacoustic transduction, the sound production device comprises a shell, a vibration system, a magnetic circuit system and an elastic piece, the vibration system comprises a plane diaphragm and a voice coil connected to the plane diaphragm, the periphery of the plane diaphragm is connected with the shell, the magnetic circuit system is connected to the shell, and the elastic piece is connected with the magnetic circuit system. The magnetic circuit system comprises a magnetic conductive yoke and a central magnetic part and an edge magnetic part which are arranged on the magnetic conductive yoke, the edge magnetic part is located on the outer side of the central magnetic part and is spaced from the central magnetic part to form a magnetic gap, the voice coil corresponds to the magnetic gap, one end of the elastic piece is connected with the plane diaphragm and / or the voice coil, and the other end of the elastic piece is connected with the plane diaphragm. The other end of the elastic piece is connected with the magnetic circuit system. The invention aims to provide the sound production device capable of increasing the effective vibration area, and the sound production device cancels a folding ring structure of a conventional vibrating diaphragm, thereby not only increasing the effective vibration area and improving the sensitivity, but also facilitating the adjustment of the amplitude symmetry of a product and reducing the total harmonic distortion of the product.

The invention relates to the technical field of LED screens, and discloses a sound transmission assembly and a sound transmission LED movie screen, and the sound transmission assembly comprises a sound transmission display unit, a medium-high frequency loudspeaker unit and a safety link protection unit. The medium-high frequency loudspeaker unit is arranged on the rear side of the sound transmission display unit; the safety link protection unit comprises a safety link protection shell and a safety link protection link; when the safety link protection shell is closed, the sound transmission display unit and the medium-high frequency loudspeaker unit are packaged into a whole. When the safety link protection shell is opened, the safety link protection link is triggered to transmit a protection signal to the LED projection system, so that the LED projection system stops projection; wherein the safety link protection link is connected with the LED projection system. The sound transmission assembly provided by the invention is protected by the safety link protection unit, and projection is stopped once the safety link protection shell is manually opened and damaged, so that the projection content of the LED screen is effectively prevented from being stolen and recorded through the sound transmission assembly.

A multi-phase power converter comprises at least two-phase power conversion circuits and a control signal generation unit. Each power conversion circuit comprises a switch bridge arm formed by an upper switch and a lower switch which are connected in series. The control signal generating unit obtains the load state of the multi-phase power converter according to the received output current of the multi-phase power converter and provides control signals for the upper switches and the lower switches. When the load state is a light load state, the control signal generating unit correspondingly turns on or off the upper switch and the lower switch, so that the at least two phases of switch bridge arms are driven alternately. The invention further relates to a control method of the multi-phase power converter.

The invention discloses a control device for reducing a THD value of a PFC circuit and a control method thereof, and relates to the technical field of PFC circuits. The control device comprises a microcontroller unit and a PI controller provided with a current loop and a voltage loop. The microcontroller unit inputs voltage change parameters to the voltage loop of the PI controller based on obtained external load information and current input voltage, and obtains a power factor value higher than a preset PFC threshold value. Obtaining an output voltage of the voltage loop, and calculating a voltage difference value between the output voltage and a preset reference voltage; calculating an input voltage effective value of the voltage loop, and obtaining a reference current value of the current loop; the input current is compared with a reference current value of a current loop, the duty ratio of a synchronous PWM signal of a PI controller is calculated and determined based on a current loop of the PFC circuit, and the microcontroller unit performs optimization control on the PFC circuit based on the duty ratio of the synchronous PWM signal; the PFC circuit has the effect of further reducing the THD value of the PFC circuit.

The embodiment of the invention discloses a driving circuit, an inverter, a circuit board and electronic equipment. A comparator receives inductive current and reference current of the inverter, and the output end of the comparator is connected with the first input end of a trigger; the second input end of the trigger is connected with the first end of the first filter, and the output end of the trigger is connected with the first input end of the latch; the second input end of the latch is connected with the output end of the first timer, the output end of the latch is connected with the input end of the NOT gate module and the first end of the second filter, and the output end of the NOT gate module is used for controlling the on-off of the auxiliary switching tube; the second end of the second filter is connected with the first input end of the AND gate module, the output end of the AND gate module is connected with the second end of the first filter, the second input end of the AND gate module is used for receiving a logic value corresponding to preset pulse time, and the output end of the AND gate module is used for controlling on and off of a main switching tube. Total harmonic distortion is reduced, and output current quality is improved.

The utility model relates to the technical field of multimedia equipment, and discloses a sound system and a television. The sound system comprises a plurality of sound channel sound boxes, wherein the plurality of sound channel sound boxes comprise a main sound channel sound box, a middle sound box, a sky sound box, a surround sound box and a mega bass sound box which are arranged at intervals; wherein the number of the mega bass sound boxes is two, and the two mega bass sound boxes are respectively arranged at two opposite sides of the middle sound box. According to the application, the low-frequency sound pressure of the sound system can be improved, the total harmonic distortion is reduced, and purer and more natural bass performance is provided, so that the immersion of the sound system is improved, and the use experience of the sound system of a user is improved.

The invention belongs to the technical field of controllable seismic sources, and particularly provides a seismic source system and a control method and device thereof, a storage medium and electronic equipment, and the seismic source system comprises a liquid source, a vibration execution part, a first servo valve, a second servo valve and a control assembly. The vibration execution part comprises a first hydraulic cavity and a second hydraulic cavity; the first servo valve comprises a first control port, a first liquid inlet and a first liquid outlet, the first liquid inlet is communicated with a liquid source, and the first liquid outlet is communicated with the first hydraulic cavity; the second servo valve comprises a second control port, a second liquid inlet and a second liquid outlet, the second liquid inlet is communicated with the liquid source, and the second liquid outlet is communicated with the second hydraulic cavity; the control assembly is electrically connected with the first control port and the second control port, and the control assembly is used for controlling the opening degree of the first servo valve and the opening degree of the second servo valve. A double-valve-body structure is adopted, the odd harmonic distortion degree is reduced, the deep geological structure recognition precision is improved, and technical support is provided for high-resolution oil and gas reservoir exploration.

The invention relates to the technical field of energy storage converters, in particular to a control method, device, equipment and medium for a low-carbon building energy storage converter, and the method comprises the steps: constructing a double-ring sliding mode controller based on RMRA control and PI control, and enabling the parameters of the PI controller to be dynamically adjusted through a self-adaptive sliding law; selecting a reference model to generate an ideal output voltage signal, and adaptively controlling the MRAC through model reference to adjust parameters of a PI controller according to an error between ideal output and actual output; the current loop and the voltage loop are decoupled, coupling on the d axis and the q axis is eliminated, and independent control equations of a current controller and a voltage controller are obtained; based on a double-loop sliding mode controller and decoupled current loop and voltage loop control, the output voltage of the converter is dynamically adjusted, the output voltage is kept consistent with a reference model, and harmonic distortion is reduced. According to the method, the worst conditions such as load sudden change and nonlinear load can be responded.

This application provides a driving circuit for driving a load. The input terminal of the input adjustment circuit receives the input voltage, and the output terminal of the input adjustment circuit is grounded. The input terminal of the high power factor module and the first input terminal of the anti-flicker module are connected to the input terminal of the input adjustment circuit. The first terminal of the load is connected to the output terminal of the high power factor module, the second terminal of the load is connected to the second input terminal of the anti-flicker module, and the output terminal of the anti-flicker module is connected to the output terminal of the input adjustment circuit. This application can automatically switch its operating state according to the dimming angle. When the dimming angle is greater than a first predetermined value or when dimming is not performed, the high power factor module adjusts the input current of the input adjustment circuit into a multi-segment current to reduce total harmonic distortion and improve power factor and efficiency. When the dimming angle is less than or equal to the first predetermined value, the anti-flicker module adjusts the output current of the anti-flicker module to prevent the LED beads from flickering.

The present invention discloses a method, device, equipment and storage medium for predictive current control of a permanent magnet synchronous motor, which constructs a time domain difference equation of current harmonics by performing sliding Fourier transform analysis on the sampled current value in a two-phase stationary coordinate system; then, based on the permanent magnet synchronous motor model, the current prediction value corresponding to each voltage vector is calculated according to the sampled current value and eight voltage vectors of the inverter; then, the pre-acquired current reference value is input into the time domain difference equation to calculate the current harmonic reference value, and each current prediction value is respectively input into the time domain difference equation to calculate the current harmonic prediction value corresponding to the current prediction value; the current harmonic reference value and each current harmonic prediction value are respectively used as a set of input data, and are input into a pre-constructed cost function for calculation, and then the optimal voltage vector with the smallest cost function is selected. The present invention minimizes the current harmonic amplitude, thereby selecting the optimal voltage vector of the system, and has better robustness.

The invention belongs to the technical field of alternating current motors and driving control, discloses a three-phase series winding motor three-dimensional space vector modulation strategy and an overmodulation processing method, and aims to improve the control performance of a three-phase series winding motor and provide positive zero-sequence current suppression capability. The invention provides a three-phase series winding motor three-dimensional space vector modulation strategy based on a space slicing method and an overmodulation strategy thereof, a series winding motor three-dimensional linear modulation area is effectively expanded, a simple and effective basic voltage vector selection table is provided, and an accurate linear modulation area mathematical model is given. In addition, a corresponding three-dimensional overmodulation method is provided, and the control performance of the series winding motor in a linear modulation area and an overmodulation area is improved.

The present application discloses a Buck-Boost PFC converter and electrical equipment; it relates to the field of power electronics technology, and solves the problems of large startup surge current of traditional Boost PFC converters, high harmonic distortion of input current of bridge Buck-Boost PFC converters, and concentrated thermal stress of main switch devices. In the present application, the main switch tube at the Buck end is moved forward to the source side, and works symmetrically in the positive and negative half-power frequency cycles, which helps to reduce thermal stress and improve conversion efficiency; the converter can automatically switch between Boost, Buck-Boost, and Buck modes by real-time monitoring of input and output voltages, which improves the adaptability and reliability of the system; improves the adaptability and efficiency of the system; the variable conduction time control based on the variable slope sawtooth wave achieves unity power factor, improves overall conversion efficiency and reduces total harmonic distortion.

The invention discloses an energy storage system multi-target cooperative control method, system and device and a storage medium, and the method comprises the steps: a controller obtains the day-ahead load prediction data of a regional power grid, sets a charging and discharging power threshold value based on the day-ahead load prediction data, and generates a basic active power instruction; after the basic active power instruction is generated, the controller introduces virtual synchronous machine control logic to obtain a final active power reference value conforming to the battery health constraint and the power grid frequency constraint; calculating the residual capacity of the energy storage converter based on the active power reference value, and calculating a compensation coefficient based on a harmonic component and a reactive component in the load current; and according to the residual capacity and the compensation coefficient, determining the current operation condition and synthesizing a final control instruction to drive the energy storage converter to output. Reactive support and harmonic treatment are carried out by using the residual capacity of the energy storage converter, and virtual synchronous machine control and charge state adaptive adjustment are combined, so that the maximization of the operation benefit of the energy storage system and the improvement of the power quality of the power grid are realized.

The utility model discloses a coaxial one-piece earphone horn, which comprises a surface cover, a support, a low-frequency driving unit, a high-frequency driving unit and a PCB (printed circuit board), the surface cover is arranged on the surface of the support, the low-frequency driving unit and the high-frequency driving unit are arranged in the support, and the PCB is arranged on the back of the support. The low-frequency driving unit comprises a low-pitch voice coil, a low-pitch voice diaphragm, a low-pitch washer, a low-pitch magnet and a low-pitch U-shaped cup, the high-frequency driving unit comprises a high-pitch voice diaphragm, a high-pitch voice coil, a high-pitch washer, a high-pitch magnet, a high-pitch U-shaped cup and a high-pitch tuning net, the high-pitch U-shaped cup is connected to the bottom of the surface cover, the high-pitch voice diaphragm is arranged at the center of the support in a wrapping mode, and a second cavity is formed by the high-pitch voice diaphragm and the high-pitch U-shaped cup. The high-pitch voice coil, the high-pitch washer and the high-pitch magnet are installed in the second cavity. The method has the advantages of good transient response, low harmonic distortion, and good flexibility and dynamic mechanical properties.

The invention provides a magnetic ring preparation method and device. The method comprises the following steps: obtaining cubic or spherical sample magnetic powder; the particle size distribution value of the sample magnetic powder meets a first threshold value; a finite element simulation mechanism is utilized to adjust the magnetic pole shape and position distribution of the prefabricated magnetic ring, and a target magnetic field direction meeting multi-pole normal distribution is obtained; based on the target magnetic field direction and oil pump parameters, bidirectionally pressing the sample magnetic powder to form a magnetic ring green body; oil pump parameters are used for adjusting pressing or powder adding pressure; the two directions are pressing directions of the upper side and the lower side of the prefabricated magnetic ring; and performing multi-gradient sintering heat treatment on the magnetic ring green body to obtain the target magnetic ring. In conclusion, according to the technical scheme provided by the invention, the magnetic field waveform sine degree of the magnetic field finished product can be improved, the total harmonic distortion is reduced, the accuracy is improved, and the method can adapt to various application scenes.

The invention discloses a portable AC-DC voltage converter which comprises an AC-DC input loop, a charging module, a lithium battery, an inversion module, an isolation boosting transformer, a central processing unit control unit, a touch screen and an output relay. The input loop charges the lithium battery through the charging module, the lithium battery provides a power supply for the isolation boosting transformer through the inversion module, the boosting transformer outputs multi-stage alternating voltage and distributes the multi-stage alternating voltage to a load through the output relay, and the central processor control unit acquires parameters such as voltage and current in real time based on neural network prediction and fuzzy control rules. The SPWM signal modulation duty ratio of the inversion module is dynamically adjusted, and stable voltage output is achieved. Multi-power-supply compatibility is achieved through the alternating current and direct current self-adaptive charging module, the dynamic response capacity and control precision are improved through neural network predictive control, the voltage stability is ensured through fuzzy control rules, the functions of overload protection, short circuit protection and real-time adjustment are achieved, and the application range is wide.

The present invention relates to a shore-based variable frequency power supply micro-power consumption full-power test method and system under weak power grid conditions, wherein the power supply variable frequency power supply V1 includes a frequency converter VFP1, the shore-based variable frequency power supply V2 includes a frequency converter VFP2, the energy-feeding load power supply V3 includes a frequency converter VFP3, the input end of the frequency converter VFP1 is connected to the shore-based high-voltage power supply, the output end of the frequency converter VFP1 is connected to the input end of the frequency converter VFP2, the output end of the frequency converter VFP2 is connected to the input end of the frequency converter VFP3, and the output end of the frequency converter VFP3 is respectively connected to the output end of the frequency converter VFP1 and the input end of the frequency converter VFP2; the energy-feeding load power supply V3 is used as a simulated load to test the shore-based variable frequency power supply V2, and after the shore-based variable frequency power supply V2 is tested, the shore-based variable frequency power supply V2 is put into use. The advantages of the present invention are: after the test loop forms a loop, no actual work is required, only the current needs to be increased to a predetermined test value, the energy consumption is small, and the power grid does not need to provide a large capacity.

The invention discloses an alternating-current micro-grid frequency adjusting device adopting fuzzy logic, and relates to the technical field of micro-grid control, comprising an initialization module for initializing parameters; the data acquisition module acquires operation parameters in real time; the hierarchical control module comprises a primary control unit and a secondary control unit, the primary control unit outputs frequency and output voltage based on a droop control strategy, and the secondary control unit performs fine adjustment on frequency deviation and voltage deviation of adjustment of the primary control unit according to fuzzy logic; and the simulation optimization module constructs a micro-grid simulation model, performs simulation verification, and obtains optimal PI controller parameters by optimizing an objective function. By adopting fuzzy logic control and an objective function optimization algorithm, PI controller parameters are dynamically optimized, the stability of the micro-grid is effectively improved, the electric energy quality is optimized, frequency fluctuation and harmonic distortion are reduced, meanwhile, multi-objective optimization is achieved, and efficient and stable operation of the micro-grid under complex working conditions is ensured.

The present invention discloses a variable gain amplifier suitable for a biomedical signal acquisition analog front end, comprising capacitors C1 and C2, NMOS tubes M1, M2, M5 and M6, PMOS tubes M3, M4 and M5. FB1 、M FB2 、M FB3 、M FB4 , resistor R cm1 , R cm2 , Rs, current source I L1 ,I L2 , and transconductance amplifiers A1 and A2. NMOS tubes M1 and M2 are used as input tubes, PMOS tubes M3 and M4 are used as active loads, and resistor Rcm not only outputs common mode voltage Vcm for the circuit, but also adjusts the gate voltage and output voltage Vout of PMOS tubes M3 and M4 at the same time. PMOS tubes MFB1 and MFB2 and transconductance amplifier A1 convert the output voltage into a small signal current output and are connected to the gates of NMOS tubes M5 and M6 to form a negative feedback network. The present invention can achieve higher loop gain and lower total harmonic distortion, and has better linearity. Within the range of input signal amplitude of 0 to 30 mV, the total harmonic distortion corresponding to the maximum input signal amplitude is not greater than 0.5%.