15results about How to "Reduce Harmonic Distortion" patented technology

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 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.

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.

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 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 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 moving coil supporting and connecting mechanism and a high-frequency vibration testboard comprising the same. The moving coil supporting and connecting mechanism comprises a first supporting and connecting piece and a second supporting and connecting piece, the first supporting and connecting piece comprises a first connecting plate made of a carbon fiber material, the size of the first connecting plate in the circumferential direction of a vibration table top is d11, the size of the first connecting plate in the axial direction of the vibration table top is d12, and d11 is larger than d12; the second supporting connecting piece and the first supporting connecting piece are arranged on the outer side of the moving coil in a staggered mode, the second supporting connecting piece comprises a second connecting plate made of rubber, the size of the second connecting plate in the circumferential direction of the vibration table top is d21, the size of the second connecting plate in the axial direction of the vibration table top is d22, d21 is smaller than d22, and d11 is larger than d21. The vibration table has extremely high vibration stability during high-frequency vibration, and the harmonic distortion degree of the vibration table is also greatly reduced through tests.

The application discloses a kind of based on translinear loop full differential operational amplifier common mode feedback circuit and full differential operational amplifier, belong to operational amplifier technical field.The application is applied to full differential operational amplifier, including common-mode voltage detection amplifier, output voltage division unit and feedback signal input unit;Common-mode voltage detection amplifier converts the difference between the common-mode voltage of the differential output end of the detected full differential operational amplifier and the target common-mode reference voltage into a differential current signal, converts it into a feedback control voltage through the output voltage division unit, and inputs the gain stage front end of the full differential operational amplifier through the feedback signal input unit, to form a negative feedback closed loop.The application embeds common-mode feedback circuit into main gain loop, improves feedback depth with the help of main amplifier high gain, realizes high bandwidth, high linearity output common mode precision control under low static power consumption, at the same time simplifies circuit structure, can improve the working stability of full differential operational amplifier under various non-ideal working conditions.

This invention discloses a speaker module, a control method, a head-mounted device, and a storage medium, applicable to the field of speaker technology. The speaker module includes: a first speaker unit, a second speaker unit, and a module housing. The first speaker unit and the second speaker unit are disposed within the module housing, and the first speaker unit and the second speaker unit have the same model number. The module housing includes a front cavity and a rear cavity. The front cavity is composed of a first front cavity of the first speaker unit and a second rear cavity of the second speaker unit, and the rear cavity is composed of a first rear cavity of the first speaker unit and a second front cavity of the second speaker unit. The audio signals received by the first speaker unit and the second speaker unit are out of phase.

The invention provides a decoupling equivalent device and method for many-to-many submodules of a flexible direct current converter valve, and relates to the field of flexible direct current transmission, and the device comprises a current generator which is used for converting an input direct current into an equivalent current; the reactor is configured to simulate a real working condition; the tested sub-module is used for receiving the equivalent current from the current generator and testing the equivalent current; one end of the test-accompanying sub-module is reversely connected to the tested sub-module in series, the other end of the test-accompanying sub-module is connected with the input end of the current generator, and the test-accompanying sub-module is configured to be used for counteracting the direct-current voltage of the tested sub-module; and the feedforward and feedback controller is connected to the current generator and is used for controlling the current generator to output equivalent current.

The invention provides a grid-connected inverter harmonic suppression method based on double-vector model predictive control, and the method comprises the steps: building an inverter prediction model under an alpha-beta static coordinate system, separating an output current into a fundamental component and a harmonic component, and carrying out the prediction control of the fundamental component and the harmonic component; a dual-target optimization function containing a fundamental wave weight coefficient eta and a harmonic wave weight coefficient gamma is constructed, minimization of an error area between PCC harmonic current and a zero axis is taken as a harmonic suppression target, and a dual-vector model is combined to predict and control a dynamic optimal voltage vector and action time thereof, so that coordinated optimization of fundamental wave power transmission and harmonic suppression is realized. The method can effectively reduce the total harmonic distortion rate at the PCC, improves the electric energy quality of a multi-inverter parallel system, and is suitable for an alternating current bus system containing multiple harmonic sources.