1791 results about "Pulse-width modulation" patented technology

The invention discloses an energy efficiency control method for a cooling fan of an industrial electric cabinet, and the method comprises the steps: firstly collecting temperature, humidity, equipment current / voltage and other multi-mode sensing data, carrying out the PCA algorithm dimension reduction and feature extraction, combining with Granger causality test, thermodynamic principle and machine learning algorithm, and carrying out the building and fusion, thereby obtaining a cooling efficiency model. Thirdly, preprocessing current and voltage data of the equipment, training and optimizing an LSTM model to predict load power, and calculating a fan rotating speed control value through a heat dissipation efficiency model; then, a PWM speed regulation signal is generated by adopting a fuzzy PID control algorithm, and a pulse width modulation and smooth speed regulation mixed strategy is applied to the duty ratio; and finally, energy efficiency indexes are collected to compare and update the weight of the LSTM model, knowledge distillation is introduced to optimize new model training, and self-adaptive adjustment of the rotating speed of the fan is achieved. The rotating speed of the fan can be accurately adjusted, energy consumption is reduced, the energy utilization efficiency is improved, performance reduction of equipment due to overheating is effectively avoided, and the service life of the equipment is prolonged.

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 present application relates to an energy-storage power-conversion series compensation system and a stability analysis method therefor, a damping controller, and an energy storage system, wherein a voltage signal on a capacitor arranged between an energy storage battery pack and a converter of the energy-storage power-conversion series compensation system can be collected, and whether an activation condition is met is determined based on the voltage signal; when the activation condition is met, an adaptive adjustment filter is activated to bring the damping controller into operation within the energy-storage power-conversion series compensation system. A voltage synchronization controller determines, on the basis of a sub-synchronous frequency band voltage signal output by the adaptive adjustment filter and an initial voltage signal, a required output phase angle signal corresponding to a pulse width modulation signal for controlling operation of the converter.

The present application provides a display panel and a display device. Pulse width modulation modules of a plurality of sub-pixels included in the same sub-pixel group receive the same frequency sweep signal, and pulse width modulation modules and the pulse amplitude modulation modules of the plurality of sub-pixels included in the same sub-pixel group receive the same light emission control signal. The start time when pixel driving circuits of at least two of the sub-pixel groups provide flow paths for corresponding driving currents according to corresponding light emission control signals is different.

The invention discloses a three-temperature test method and device for a semiconductor chip, and relates to the technical field of semiconductor chip testing, and the method comprises the steps: inputting an initialization parameter set into an impedance temperature mapping model, carrying out the phase angle analysis and multi-band feature fusion through a broadband impedance spectrum analysis method, obtaining a chip junction temperature instantaneous value, and carrying out the measurement of the junction temperature instantaneous value. A PID controller is utilized to dynamically compensate a junction temperature instantaneous value of a chip, a fuzzy rule base inference engine is utilized to map the junction temperature instantaneous value into an execution instruction set, the execution instruction set is converted into a bidirectional voltage signal through pulse width modulation, a semiconductor chilling plate is driven to perform bidirectional temperature rise and drop control in a three-temperature environment, and real-time temperature change test data is synchronously acquired. According to the method, the junction temperature instantaneous value of the chip can be more accurately obtained by combining broadband impedance spectroscopy analysis with a multi-band characteristic fusion technology, and meanwhile, the PID controller is combined with the fuzzy rule base inference engine, so that a response can be quickly made under the condition that the temperature is quickly changed, and the response capability is greatly improved.

Described embodiments include a control circuit with a first comparator having a first comparator input receiving a first threshold voltage, and a second comparator input coupled to an output voltage terminal. A second comparator has a third comparator input receiving a second threshold voltage, and a fourth comparator input coupled to a current output terminal. A first logic circuit provides a true signal at its output responsive to a particular number of its inputs receiving a true input. A second logic circuit has inputs coupled to the first comparator output, and to the first logic output. A variable resistance circuit has an output coupled to a mode detection output. An amplifier has inputs coupled to the variable resistance circuit output, and a third reference voltage source. A duty cycle generation circuit provides a respective pulse width modulation (PWM) signal at each of its respective duty cycle outputs.

The invention relates to the technical field of emergency mobile power supplies, and discloses a control method of an emergency mobile power supply and the emergency mobile power supply, and the method comprises the steps: carrying out the operation parameter data collection and adaptive wavelet transform noise reduction of the emergency mobile power supply, and obtaining a standardized feature matrix; performing hierarchical feature extraction through an extended convolutional capsule network to obtain global power supply features and local power supply features; establishing a deep deterministic strategy network for power supply state scoring to obtain a state scoring result; inputting historical data in the experience playback pool into an action generation module, performing optimization iteration on the control action to obtain a first control strategy, and recording state transition data in a control process; and carrying out power loss compensation control analysis to obtain compensation control quantity, superposing the compensation control quantity to obtain a second control strategy, carrying out PWM (Pulse Width Modulation), and generating a charging and discharging control signal. According to the invention, accurate power regulation and energy storage unit control are realized, and stable operation of the system is ensured.

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.

Disclosed is a direct control method and system for an internal potential of a bridge arm of a new energy grid-tied inverter (GTI), the control method including the following steps. Measured values are obtained by measuring a port voltage and a port current of a GTI, instantaneous active and reactive power values are calculated, and a phase angle and amplitude reference of an internal potential of a bridge arm are obtained to generate reference values thereof. The internal potential of the bridge arm is estimated, and an estimated value used as a feedback signal, after being compared with the reference values, is sent to an internal potential controller to obtain a modulating signal, which is sent to a pulse width modulation (PWM) module, realizing direct control of the internal potential of the bridge arm. In the present disclosure, the dynamic performance of the GTI is improved while improving power quality.

The invention provides a constant-voltage PWM dimming system for improving the brightness change of a light source, and the system comprises a controller, and a PWM wave generation module in the controller controls the light source to be turned on based on a set duty ratio. The current acquisition module controls and acquires actually measured current; the temperature acquisition module acquires real-time temperature, and the current mapping module calculates theoretical current according to a linear mapping function of the temperature and the current; the current compensation module obtains compensation current; the duty ratio mapping module obtains a theoretical duty ratio corresponding to the compensation current by using a linear mapping function of the current and the duty ratio; the duty ratio adjusting module compares the theoretical duty ratio with the duty ratio set by the current PWM wave generation module, resets the duty ratio, outputs a PWM control signal according to the newly set duty ratio, and controls the light source to be lightened; according to the system, a feedback adjustment mechanism is established, so that the brightness of a light source is dynamically balanced in an interval, and obvious change of a brightness value is avoided; the method is suitable for accurate dimming control of various types of LED light sources.

A power converter topology, comprising: a cascade connection of a first converter stage and a second converter stage; wherein the first converter stage comprises a current mode controlled pulse width modulation (PWM) converter having one or more pairs of switches forming a first switching bridge and an inductor connected to the output of the first switching bridge, the switching bridge generating a voltage Vlink; and wherein the second converter stage is a resonant converter having a switching stage having one or more pairs of switches forming a second switching bridge across the voltage Vlink generated by the first converter stage and a resonant tank connected to the output of the second switching bridge, to generate a resonator output voltage; the topology further comprising a transformer to transform the resonator output voltage to a transformed output voltage and a rectifier to rectify the transformed output voltage to an output voltage Vout, and wherein the duty cycle of the first switching bridge is varied according to a voltage derived from the value of the output voltage Vout, and wherein the duty cycle of the second switching bridge is fixed at 50:50.

A pulse width modulation control circuit for controlling a power converter circuit includes: a main loop control circuit; and a light-load loop control circuit. The light-load loop control circuit includes a current synthesis circuit configured to generate a synthesized current signal according to an input voltage and a target value of an output voltage and an inductance value of an inductor in a power stage circuit of the power converter circuit. The light-load loop control circuit generates a pulse modulation signal in light-load mode according to the synthesized current signal, to control a duty ratio of the power stage circuit. In the light-load mode, the main loop control circuit enters a power-saving state to reduce the power consumption of the pulse width modulation control circuit. The power-saving state includes: reducing the power consumption of the current sense circuit or stopping the operation of the current sense circuit.

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 relates to an energy storage variable flow series compensation system and a stability analysis method thereof, a damping controller and an energy storage system, which can collect a voltage signal arranged on a capacitor between an energy storage battery pack and a converter of the energy storage variable flow series compensation system, and judge whether an activation condition is met based on the voltage signal. And activating the self-adaptive adjustment filter under the condition that the activation condition is met, so that the damping controller is put into operation of the energy storage variable flow series compensation system. And the voltage synchronous controller determines an output phase angle signal required corresponding to a pulse width modulation signal for controlling the operation of the converter according to the subsynchronous frequency band voltage signal output by the self-adaptive adjustment filter and the initial voltage signal. According to the scheme, under the condition that the activation condition is met, the damping controller can be put into operation of the energy storage variable flow series compensation system, the damping level of an unstable subsynchronous resonance mode is improved, an original negative damping mode is corrected into a positive damping mode, and the stable operation capacity of the grid-forming type converter is improved.

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.

The invention relates to a fan control method, a computer program product, equipment and a storage medium. The method comprises the following steps: calculating standard high level time of a pulse width modulation signal and calculating a target difference value; according to the target difference value and the standard high level time, determining a corresponding relationship between the plurality of high level times and the plurality of control state values, and determining a control state value combination of each pulse width modulation signal group in the plurality of pulse width modulation signal groups, function definition of the control state value combination corresponding to the control state value combination of each pulse width modulation signal group; and obtaining a function definition of a target control state value combination matched with the fan control information, determining the target control state value combination, assembling according to a preset rule to form a pulse width modulation signal sequence group, and regulating and controlling the fan based on the pulse width modulation signal sequence group. By adopting the method, the system reliability can be improved.

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 herein are components of an electrolysis system and components and methods of operation thereof to improve electrolysis operations. The electrolysis system includes a pulse width modulation control system that adjusts voltage and current applied to an electrolytic cell by modulating a duty cycle of a high frequency waveform. The voltage and current are adjusted based on data provided by one or more feedback loops that monitor performance characteristics of the electrolyzer.

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 microwave motion detection system and lighting applications are disclosed. Time slicing and Pulse Width Modulation (PWM) techniques are used to improve efficiency in microwave motion detection sensors. Systems employing motion detection may control the detection of irrelevant motion with shielding and changing the power of the microwave motion detection sensor. Distance-based zones may be designated, and motion may be detected in particular zones. Different device operation may be performed based on motion detection in different zones. In lighting applications, varying device operation may include varying the direction, amount, or duration of light output. Device operation, when motion is detected, may also be based on the time of day, user preference, and power status parameters.

Described herein is a method of operating a power electronic converter device for an electrical power conversion system. The power electronic converter device includes a converter circuit including an input side, an output side, a first converter, and at least one second converter. The second converter includes at least one floating cell with a DC intermediate circuit and semiconductor devices. The method includes: switching the semiconductor devices of the floating cell at switching instants determined with optimized pulse patterns or carrier-based pulse width modulation; determining a fundamental voltage component for the floating cell; and generating the fundamental voltage component in the actual voltage of the floating cell by modifying the switching instants, such that a voltage VC AF of the DC intermediate circuit is lying in a given reference voltage range for balancing the DC intermediate circuit of the floating cell.

A switching power supply includes: a first amplifier configured to output a first error signal commensurate with a difference between an output voltage or a feedback voltage commensurate therewith and a predetermined reference voltage; a second amplifier configured to output a second error signal commensurate with a different between the feedback voltage and the first error signal; a ramp signal generation circuit configured to generate a ramp signal; a pulse width modulation (PWM) comparator configured to generate an off signal by comparing the second error signal with the ramp signal; a control circuit configured to generate a control signal based on the off signal; and a switching output circuit configured to generate the output voltage based on the control signal.

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.

The invention provides a motor rotor magnetic pole initial position identification method and device and a medium, and the method comprises the steps: determining the parameters of a rotating square wave according to the current response frequency and pulse width modulation square wave frequency of a permanent magnet synchronous motor, and the parameters of the rotating square wave comprise a period, a rotating speed and a voltage amplitude; determining the duration of the rotating square wave according to the parameters of the rotating square wave; applying a square wave voltage excitation signal to the permanent magnet synchronous motor according to the parameters and the duration of the rotating square wave, and determining a direct-axis response current characteristic signal and a target electrical angle of the permanent magnet synchronous motor; and according to the direct-axis response current characteristic signal and the target electrical angle, determining and verifying the initial position of the rotor magnetic pole of the permanent magnet synchronous motor so as to improve the identification precision and robustness of the initial position of the rotor magnetic pole of the motor.

A pixel includes a light-emitting element, a pulse width modulator controlling an emission time duration of the light-emitting element based on a data voltage, and a constant current generator providing a driving current having a constant level to the light-emitting element based on a constant current generation voltage. The pulse width modulator includes a first driving transistor, and an N-type transistor connected to a gate electrode, a first electrode and a second electrode of the first driving transistor. The constant current generator includes a second driving transistor, and an N-type transistor connected to a gate electrode, a first electrode and a second electrode of the second driving transistor.

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.