1250 results about "Pulse-width modulation" patented technology

The invention discloses a low-voltage ride-through control method of a flywheel energy storage system, which is based on a low-voltage ride-through control strategy of model predictive current control (MPCC) so as to improve the low-voltage ride-through capability of the flywheel energy storage system when a power grid fails. A future current value is predicted through system modeling and a prediction algorithm, so that effective control is realized. The MPCC-based machine side-power grid side coordination control strategy can quickly respond to the voltage sag of the power grid, provide reactive power support, stabilize the voltage of the direct current bus, and ensure the safe and reliable operation of the flywheel energy storage system during the voltage sag period of the power grid. A traditional pulse width modulation (PWM) technology is abandoned, the optimal switching state is directly selected through a limited control set, and hardware implementation of a power grid side converter is simplified. A differential control strategy aiming at a power grid symmetric fault (three-phase voltage sudden drop) and an asymmetric fault (single-phase grounding) is provided, the method is suitable for a complex power grid fault scene, and the system universality is improved.

The invention provides a frying and baking equipment heat preservation automatic control method and system, and relates to the technical field of food processing equipment control, and the method comprises the steps: collecting temperature signals of different positions through a plurality of groups of thermocouples and infrared thermal imaging sensors which are arranged in a frying and baking area, constructing a dynamic three-dimensional temperature field model, and obtaining a dynamic three-dimensional temperature field model; calculating a temperature standard deviation and a maximum temperature gradient in real time according to the dynamic three-dimensional temperature field model; and when the temperature standard deviation is larger than or equal to a preset threshold value, according to the heat distribution difference of the three-dimensional temperature field model, a multi-region differential compensation strategy is generated, the power distribution proportion of each heating unit is dynamically adjusted, and the duty ratio parameter of pulse width modulation is optimized in real time. Through multi-sensor accurate monitoring, dynamic regulation and control and intelligent stop judgment, uniform and stable temperature control, energy conservation and consumption reduction are achieved, the service life of equipment is prolonged, meanwhile, the use safety of a user is guaranteed, and the cooking experience is improved.

The invention belongs to the technical field of emergency power supply of power supply vehicles, and particularly discloses and provides an emergency power supply system of a large mobile storage and charging power supply vehicle, which comprises a vehicle-mounted energy storage unit, a power conversion unit, a PWM (Pulse Width Modulation) signal generation unit, a load monitoring unit and a control unit. The control unit determines a grid-connected mode or an off-grid mode by collecting the on-off state of a power grid and the total power of a load and calculating the power change rate. During grid connection, a voltage instantaneous value is monitored, and a power supply process is executed after locking cooperative control is triggered. Load impact components are identified and verified in the off-grid process, loads are cut off in a graded mode and cyclic verification is conducted if the load impact components do not pass or power exceeds the limit, and after the load impact components pass, time sequence graded loading control is executed according to the adjustment stage number determined by the load type and the proportion. According to the invention, flexible selection between grid connection and grid disconnection can be realized according to actual working conditions, the condition of single power supply mode is changed, the adaptive capacity to different scenes is improved, the real uninterruptible power supply requirement is met, and the impact load is precisely controlled.

The invention relates to a light sensation self-adaption and white balance cooperative adjustment method and device for an LED display screen, and the method comprises the steps: collecting the illumination value of current ambient light and the spectral distribution of the ambient light, and calculating the color temperature value of the ambient light; according to the color temperature value, inquiring a pre-stored color temperature-gain parameter corresponding relation library to determine a corresponding white balance gain parameter; according to the illumination value, a backlight brightness adjustment amount is calculated through a pre-constructed logarithm compensation model; associating and binding the white balance gain parameter and the backlight brightness adjustment amount, and outputting the white balance gain parameter and the backlight brightness adjustment amount to a pulse width modulation signal generation unit and a digital-to-analog converter through a microcontroller; and outputting the white balance gain parameter to a digital-to-analog converter, outputting the backlight brightness adjustment amount to a pulse width modulation signal generation unit, generating a synchronous adjustment signal to drive an LED display unit, and carrying out cooperative adjustment of backlight brightness and white balance so as to achieve the purpose of unified regulation and control of visual comfort and color rendition authenticity.

The invention discloses a battery pack equalization control method and system based on multidimensional state mapping, and the method comprises the steps: obtaining terminal voltage data, working current data and surface temperature data of each single battery in a target battery pack; calculating an ohm internal resistance value and a polarization impedance value of each single battery; calculating an impedance growth rate; according to the impedance growth rate and the surface temperature data, a health state value is determined, and an aging weighting coefficient is determined; determining a polarization safety coefficient of each single battery based on the polarization impedance value; calculating a state-of-charge value of each single battery in the target battery pack, and determining a balance demand deviation degree; determining a basic equalization duty ratio of each single battery according to the equalization demand deviation degree; correcting the basic balance duty ratio to generate a target pulse width modulation duty ratio; and according to the target pulse width modulation duty ratio, controlling equalization circuits connected to the two ends of each single battery to be switched on. The battery pack equalization control efficiency is improved.

The invention relates to a method for passive arc suppression in an electrical treatment of plants, comprising the step: (S400) Applying a pulse-width modulated direct electrical current (I) to the plants.

The invention belongs to the technical field of new energy, and particularly relates to a fault voltage ride-through optimization method and system for a network construction type energy storage converter. Carrying out positive and negative sequence separation and Clark-Park coordinate transformation on the three-phase power grid voltage and the inversion current, calculating active power and reactive power of the network-forming type energy storage converter, and carrying out power loop control to obtain three-phase reference voltage and angular velocity; performing voltage loop control, and dynamically adjusting a positive sequence active current and a positive sequence reactive current according to whether a low-voltage-crossing indication signal exists or not; performing positive-sequence current loop control and negative-sequence current loop control, and then performing inverse Clark-park conversion to obtain positive-sequence three-phase reference voltage and negative-sequence three-phase reference voltage; and superposing the positive-sequence three-phase reference voltage and the negative-sequence three-phase reference voltage for PWM (Pulse Width Modulation). According to the invention, when the power grid voltage is unbalanced due to a fault, the oscillation of the direct current side voltage and power caused by the negative sequence component is eliminated, and the power angle stability is improved and the fault current is suppressed by dynamically adjusting the related reference value during the fault voltage ride-through period.

In one aspect of the disclosure, a variable-current gate driver includes a plurality of inputs for receiving pulse-width-modulation (PWM) control signals transmitted from a processing system. Current sources controlled based on the pulse-width modulation (PWM) signals are coupled to respective gates of at least two transistors of a hybrid switch in the power module (PM) including different semiconductor technologies. The current sources are coupled respectively to at least one other non-gate terminal of the transistors. The current sources provide the slew rate control of the PM using variable current values to compensate for differences in the at least two semiconductor technologies in real-time to reduce switching losses and maximize efficiency.

Disclosed in the present invention are a control method and system capable of providing frequency support for a flexible interconnected power distribution network. The method comprises: using a permanent-magnet direct-drive wind turbine connected to a flexible interconnected power distribution network to provide frequency support, measuring a direct-current voltage of a grid-side converter of the wind turbine, calculating a per-unit value and the phase of the direct-current voltage, and calculating the amplitude of a modulation voltage; generating a trigger pulse signal; monitoring the rotation speed of a wind turbine rotor and the rotor position angle of a synchronous generator, and acquiring a per-unit value of optimal power; calculating an active power reference value; on the basis of active power control and current control, outputting a d-axis component and a q-axis component of a modulation voltage of a generator-side converter, and by means of rotating coordinate transformation, generating a three-phase modulation voltage in a stationary coordinate system; and generating a trigger pulse signal by means of a pulse width modulation stage. The present invention enables wind turbines to provide quick response for power distribution networks in a frequency support stage, and prevent rotation speed stalling and suppress secondary frequency drop in a rotation speed recovery stage, thereby improving the support capability of the wind turbines for power grids.

A bidirectional high voltage AC-DC converter includes a primary three-phase three-level T-type power factor correction circuit, a full-bridge switching circuit connected to the primary three-phase three-level T-type power factor correction circuit output, an isolated capacitor-inductor-inductor-capacitor (CLLC) resonant tank connected to the full-bridge switching circuit, a T-type full-bridge output topology circuit connected to the CLLC resonant circuit, and a controller that controls one or more of the components of the bidirectional isolated high voltage AC-DC converter. The primary three-phase three-level T-type power factor correction circuit and the secondary three-level circuit include a split DC-link bus with respective voltages that are actively controlled by the controller. The CLLC resonant converter circuit includes an isolation transformer that electrically isolates the primary side from the secondary side of the bidirectional isolated high voltage AC-DC converter. A control method includes synthesizing, via a modified space vector pulse width modulation (SVPWM) scheme or a variable-amplitude double-carrier sine-triangle PWM with capacitor bank middle point voltage control, one or more output voltages of the front end three-phase three-level T-type PFC circuit, wherein the modified SVPWM scheme is based, at least in part on a nearest four vectors technique.

An aerosol provision device or a vapor provision device including an aerosol generator or vapor generator; a driving circuit connected to the aerosol generator or vapor generator, wherein the driving circuit is configured to employ either pulse width modulation or amplitude modulation, to supply power to the aerosol generator or vapor generator; and a power source connected to the driving circuit, wherein the power source includes a hybrid ion capacitor.

The invention relates to the technical field of LED display screen driving parameter adjustment, in particular to an LED display screen driving parameter adjustment method and system, and the method comprises the following steps: continuously collecting the operation parameters of each local area of a display screen; calculating the accumulated heat pressure of each local area in real time; when the accumulated heat pressure of the local area is equal to or greater than an early warning threshold value, identifying that the local area is an overheating risk area; the driving parameters of the overheating risk area are adjusted, the adjustment comprises reduction of the peak driving current of the LED lamp beads in the local area or adjustment of the pulse width modulation duty ratio of the peak driving current of the LED lamp beads in the local area, and therefore the instantaneous thermal load of the local area is reduced; and when the actual energy consumption is increased beyond the energy consumption standard, the driving strategy of the local area is optimized by combining the data of the accumulated heat pressure of the local area. The driving parameters are monitored in real time and dynamically adjusted, and energy consumption is optimized, so that the service life of the display screen is prolonged, and the operation stability is improved.

The invention provides an infrared oil measuring instrument for driving an infrared LED lamp through a pulse signal, relates to the technical field of detection, and comprises the steps of generating a pulse width modulation signal, generating a constant peak current based on the pulse width modulation signal, and driving the infrared LED lamp with a preset characteristic absorption wave number to emit pulse infrared light. After passing through the measuring tube containing the solution to be measured, the pulse infrared light receives transmission light and converts the transmission light into electric signals, all the electric signals are processed to generate absorbance values, and the oil concentration is calculated based on the absorbance values and a preset calculation model. The LED light source intensity is improved through pulse driving, multi-wavelength characteristic detection and constant current control are combined, the measurement precision and the system stability are remarkably improved, the manufacturing cost is reduced, and the device is suitable for online or portable oil product monitoring scenes.

The invention relates to the technical field of electroluminescent light sources, and provides a self-adaptive LED illumination regulation and control method based on multi-modal environment perception, which comprises the following steps: acquiring multi-modal environment perception data, user feedback data, blue light risk level and user physiological rhythm data; performing space-time alignment on the multi-modal environment sensing data and the user feedback data, performing data enhancement, and extracting a fusion feature vector in an enhanced data set; performing dynamic weighting on the fused feature vector, generating an initial illumination parameter in combination with the weighted feature vector and the user physiological rhythm data, and performing energy-saving optimization on the initial illumination parameter to obtain a target illumination parameter; mapping the target illumination parameter into a pulse width modulation parameter, and determining the phase delay of the micro-lens array according to the personnel distribution characteristics in the fusion characteristics; driving constant-current circuit data according to the pulse width modulation parameters, performing micro-lens beam deflection according to the phase delay of the micro-lens array, and adjusting the optical filter according to the blue light risk level.

The invention relates to the technical field of LED illumination control, and discloses a lamp strip brightness control system and method capable of realizing self-adaptive adjustment, and an LED lamp strip. An environment data acquisition module of the system acquires environment illumination intensity data and environment color temperature data in real time to form a multidimensional environment parameter matrix containing a timestamp; a dynamic feature extraction module performs multi-scale decomposition on the matrix, extracts illumination intensity change trend features and color temperature fluctuation features, and constructs dynamic feature vectors; the adaptive decision module calculates a brightness adjustment weight based on the dynamic feature vector, and generates a brightness adjustment instruction in combination with a preset brightness constraint condition; the signal synthesis module converts the brightness adjustment instruction into a pulse width modulation signal, and superposes a high-frequency noise suppression signal to optimize the signal stability; and the driving execution module adjusts the driving current of the LED lamp strip according to the pulse width modulation signal so as to realize self-adaptive brightness adjustment. The system can improve the stability and adaptability of brightness adjustment and improve the visual experience of a user.

The embodiment of the invention provides a display screen direct-drive display method based on a data algorithm, and belongs to the field of display screen display methods. The method comprises the following steps: acquiring RGB frame data and environment sensing data; preprocessing the acquired RGB frame data, generating an importance degree matrix, and grading the image area of the display screen; dynamically distributing the number of sub-cycles of pulse width modulation, matching different pulse widths for image areas of the graded display screen, and generating a compensated gray matrix by using a nonlinear compensation method; generating a dead pixel position matrix according to the scanned pixel state of the display screen, and generating a compensated brightness matrix of the display screen by using a brightness diffusion compensation method; a plurality of logic boards are dynamically synchronized by utilizing an FPGA, and a dead pixel avoidance mechanism is adopted to realize direct-drive display of a display screen. According to the invention, pocking marks are eliminated, low gray scale maintains high refresh rate, chromatic aberration is reduced, dead pixels of the display screen do not need to be halted for maintenance, cost is reduced, brightness is compensated for natural transition, and visual uniformity is compensated for.

The invention relates to an SSD (Solid State Disk) heat dissipation optimization method and system based on dynamic temperature control. The method comprises the following steps: acquiring a thermal state vector of an SSD through inner and outer ring temperature monitoring; predicting a future 5S temperature track through a long short-term memory network model, and generating a temperature prediction sequence; generating a computing power distribution proportion based on the temperature prediction sequence, and determining a capacity migration proportion at the same time; according to the real-time temperature value of each logic block in the block temperature mapping table and the computing power distribution proportion and capacity migration proportion, heat-sensitive and heat-tolerant classification is carried out on the I / O queue, and an optimized scheduling sequence is generated; calculating a power supply phase parameter according to the access frequency of the heat-sensitive block of the optimized scheduling sequence, and generating a pulse type heat dissipation control signal; the SSD power supply phase is dynamically adjusted according to the pulse type heat dissipation control signal, heat dissipation optimization is conducted through the pulse width modulation technology, updated heat state data is fed back to inner and outer ring temperature monitoring, and therefore the purpose of dynamic intelligent temperature control of the SSD is achieved.

Improvements in fluid volume measurement systems are disclosed for a pneumatically actuated diaphragm pump in general, and a peritoneal dialysis cycler using a pump cassette in particular. Pump fluid volume measurements are based on pressure measurements in a pump control chamber and a reference chamber in a two-chamber model, with different sections being modeled using a combination of adiabatic, isothermal and polytropic processes. Real time or instantaneous fluid flow measurements in a pump chamber of the diaphragm pump are also disclosed, in this case using a one-chamber ideal gas model and using a high speed processor to obtain and process pump control chamber pressures during fluid flow into or out of the pump chamber. Improved heater control circuitry is also disclosed, to provide added or redundant safety measures, or to reduce current leakage from a heater element during pulse width modulation control of the heater element. Improvements are also disclosed in an application of negative pressure during a drain phase in peritoneal dialysis therapy, and to control an amount of intraperitoneal fluid accumulation during the therapy. Improvements in efficiency are also disclosed in movement of fluid into and out of a two-pump cassette and a heater bag of the peritoneal dialysis cycler, and in synchronization of operation of two or more pumps in the peritoneal dialysis cycler or other fluid handling devices using a multi-pump arrangement.

A switching stage of a Switched Mode Power Supply (SMPS), the switching stage including a switching element including a GaN transistor connected in series with a Metal-Oxide-Semiconductor (MOS) Field Effect Transistor (FET), thereby defining a mid-node in between the GaN transistor and the MOSFET, a controller arranged for driving a gate terminal of the MOSFET based on an Pulse Width Modulation (PWM) input signal, and the controller includes first switch circuitry arranged for providing a low ohmic path between the mid-node and the gate terminal of the MOSFET and control circuitry arranged for controlling the switch circuitry based on the PWM input signal.

The invention discloses an energy storage converter predictive current control method based on data driving model self-learning, and belongs to the technical field of power electronic converter control. The energy storage converter is a half-bridge bidirectional DC-DC converter, and the method comprises the following steps: collecting the state quantity of the energy storage converter through a sensor in each control period, forming a data driving prediction model constructed by an input vector input neural network online parameter identification module, and outputting an initial duty ratio prediction value; constructing a value function, performing online optimization on an initial value through a gradient descent method to obtain a final optimal duty ratio, and simplifying a scene to directly use the initial value; comparing the optimal duty ratio with a carrier wave to generate a PWM (Pulse Width Modulation) signal to drive a power switch tube; actual inductive current is collected, an ideal duty ratio enabling the value function to be minimum is reversely solved to serve as a supervision signal, and the model weight is trained and updated online through a sample. The technical problem that traditional continuous set model predictive control depends on an accurate mathematical model is solved.

The invention provides a photovoltaic inverter common-mode resonance suppression method and device and a storage medium. The method comprises the steps of obtaining resonance current data of a common-mode loop; determining a differential negative feedback control strategy of a common-mode loop based on the resonance current data and preset common-mode current data; determining a harmonic control strategy of the system according to the first voltage data of the DC unit and the second voltage data of the power grid; determining a pulse width modulation strategy of the system based on a differential negative feedback control strategy and / or a harmonic control strategy so as to suppress common-mode resonance generated during voltage fluctuation; according to the method, the problems of current oscillation and inverter damage caused by common-mode resonance are effectively solved by obtaining the common-mode loop resonance current data and adopting the differential negative feedback control strategy to suppress resonance frequency point oscillation, combining the harmonic control strategy to eliminate the alternating current component, and finally dynamically adjusting the pulse width modulation strategy; the method has the advantage of improving the stability and safety of the system.

Disclosed is a system for zero voltage switching in a power converter with a first half-bridge and a second half-bridge. The first half-bridge has a first set of transistors and output inductor. The second half-bridge has a second set of transistors and auxiliary inductor. A current sensing means measures, at switching cycle scale, average and maximum current values of output inductor and average, minimum and maximum current values of auxiliary inductor. A voltage sensing means measures input and output voltages of first and second half-bridge. A controller is configured to compute dead times of pulse width modulation control signal of second half-bridge, generate pulse width modulation control signal of second half-bridge and to adapt dead times of first half-bridge.

The invention provides a multifunctional low-power-consumption power distribution terminal power supply system which comprises a filtering and rectifying unit. The charging and discharging management unit is integrated with an intelligent charging and discharging control algorithm, performs charging and discharging management on the charging process of the capacitor and the battery, and switches to a battery discharging mode to provide a starting power supply when the voltage of the capacitor is insufficient; wherein the intelligent charging and discharging control algorithm is an algorithm based on the combination of a fuzzy logic control algorithm and a dynamic threshold adjustment strategy; the PWM control unit is used for outputting voltage by adopting a pulse width modulation technology and automatically reducing the power to the lowest level in a non-working state; and the CPU control unit is used for controlling the normal operation of the charging and discharging management unit and the PWM control unit, and monitoring the working states of the three-stage rectification topological structure, the grading protection circuit and the high-precision acquisition circuit in real time through a built-in intelligent monitoring algorithm. Stable, reliable, efficient and low-power-consumption power supply support can be provided for the power distribution terminal, and further development of an intelligent power grid is promoted.

The invention discloses a PCB soldering paste printing three-dimensional defect detection system based on multispectral imaging, and relates to the field of machine vision detection, and the system comprises a multispectral image acquisition module, a four-channel industrial camera based on RGB and near infrared, and a tunable LED light source array; acquiring reflection characteristic data under different penetration depths through a wavelength switching mechanism; the motion control trigger module is used for realizing positioning based on an XYZ three-axis objective table driven by a servo motor in cooperation with feedback of an encoder; a pulse width modulation signal is adopted to coordinate the moving speed of a camera shutter and a platform; according to the method, RGB and NIR four-channel imaging is combined with Beer-Lambert law modeling, so that double verification of material component quantitative analysis and three-dimensional shape reconstruction is realized, and limitation of monocular vision is avoided; structured light projection and binocular stereo matching technologies are adopted, cross-frame data alignment is realized in cooperation with an ICP algorithm, and detail defects can be better detected.

A battery booster for jumpstarting a vehicle having an external battery. The battery booster may include a processor, a set of terminal connectors, a power supply, and a power-management circuit. The set of terminal connectors may be configured to couple with the external battery or an engine that is electrically coupled with the external battery. The power supply may include a lithium battery configured to supply a starting current to jump start an engine. The external battery may have a first nominal voltage, while the lithium battery may have a second nominal voltage that is greater than the first nominal voltage. The power-management circuit operatively coupled with the at least one processor, wherein the at least one processor is configured to transfer power selectively between the external battery and the power supply. The processor is configured to perform a pre-charge function and / or a back-feed function via the power-management circuit, which may employ a pulse width modulation (PWM) driver.

The invention belongs to the technical field of power supply control, and particularly relates to an improved linear gain digital signal control method applied to a power supply. Aiming at the problems of poor gain linearity, low control precision, slow dynamic response and insufficient adaptability to system parameter change in a wide load and wide input voltage range in the traditional digital control, the method comprises the following steps of: digitally acquiring power supply operation parameters at high precision, and introducing an adaptive linear gain adjustment module to calculate a target control gain. In addition, the method generates a pulse width modulation signal based on the corrected gain and digital operating parameters to regulate the power output, and samples quantized output feedback in real time. Through the scheme, the response speed and stability of the power supply system during transient load change can be remarkably improved, and power supply management with higher precision, higher robustness and faster dynamic response is realized, so that the overall performance of the power supply system is comprehensively improved.

In some aspects, the techniques described herein relate to a grid forming controller with decoupled voltage control including: a decoupled voltage control as an outer control unit; a power-based synchronization unit; and an inner current control unit, wherein the controller receives measurements from an inverter, the measurements including three-phase instantaneous PCC voltage and three-phase instantaneous converter currents, and outputs pulse width modulation signals for the inverter.

A power factor correction (PFC) control circuit includes a pulse-width modulation (PWM) circuit configured to control a switch of a switching power converter. The PFC control circuit further includes a mode control circuit configured to select a conduction mode from a plurality of conduction modes for the switching power converter based at least in part on an output power of the switching power converter and to control a beginning of a switching cycle of the switching power converter based on the selected conduction mode. In addition, the PFC control circuit includes a current regulation circuit configured to provide a regulation signal to the PWM circuit to regulate an average coil current of the switching power converter in each of the plurality of conduction modes.

A system for prognosis and control of a power module includes a gate driver circuit and a controller circuit. The gate driver circuit drives a target gate node of a target power transistor in response to a pulse width modulation signal, measures a target gate voltage, switches a desaturation signal in response to the target power transistor switching between an off state and an on state, measures a target transistor voltage, and measures a target transistor current. The controller circuit modulates the pulse width modulation signal to increase the target gate voltage, determines a target threshold voltage as the target gate voltage in response to the desaturation signal switching states, determines a target on-resistance based on the target transistor voltage and the target transistor current, and controls the target power transistor based on the target threshold voltage and the target on-resistance.

The invention provides a virtual synchronous machine grid-connected control method and device and a readable storage medium, and relates to the technical field of electric power. The method comprises the following steps: calculating grid-connected active power and actual reactive power according to inverter parameters and power grid parameters of previous grid-connected control; determining the output voltage of the inverter according to the actual reactive power and the reference reactive power; inputting the grid-connected active power, the reference active power and the rated angular frequency into a first-order low-pass filtering module to obtain a frequency deviation and a frequency change rate, and adaptively adjusting the virtual inertia according to the power difference and the frequency deviation; updating the output angular frequency of the inverter according to the sum of the frequency deviation and the rated angular frequency; and performing voltage and current double-closed-loop control on the output voltage and the output angular frequency to obtain a modulated wave signal, and performing sine pulse width modulation based on the modulated wave signal to obtain a switching control signal of the inverter. Therefore, the active power oscillation is eliminated, the active steady-state deviation is reduced, and the frequency deviation and the frequency change rate are effectively inhibited.