524 results about "Voltage limit" patented technology

The invention relates to a V2G-based alternating current charging power adjusting method and device. The method comprises the following steps: carrying out multi-scale data acquisition and preprocessing on a V2G alternating current charging system to obtain a standardized system state data set; constructing a system dynamic model comprising a power grid voltage characteristic and a charging power characteristic; carrying out decomposition to obtain a power output mapping relation calculation, and obtaining a power modulation control parameter; establishing a fast and slow time scale coordination control framework, and designing a power regulation agent and a voltage regulation agent to obtain a coordination control strategy; checking a charging power limit value constraint, a voltage limit value constraint and a power factor constraint to obtain a constraint violation judgment result, and executing constraint projection calculation to obtain a target control instruction; and controlling a power conversion circuit of the charging pile to execute power regulation operation. According to the invention, a hierarchical control structure is adopted, the control complexity of the system is reduced, and the robustness and the adaptive ability of the control strategy are improved.

The invention relates to the technical field of intelligent power grids, and provides an intelligent operation centralized control center intelligent scheduling interaction method and system, and the method comprises the steps: generating a heat distribution gradient through environment noise filtering, reflecting the temperature field change of equipment, obtaining a voltage amplitude envelope through fundamental wave and harmonic wave separation, and monitoring the power quality; a current fluctuation coefficient is extracted by combining segmented deviation analysis to evaluate a line load state, and frequency fluctuation parameters are captured by using time domain statistics to track system stability. By constructing a dynamic association map, heterogeneous data such as thermodynamics, electrical quantity, load characteristics and synchronous states are mapped to power grid topological nodes, and a cross-dimension association relationship is established to realize whole-network state coupling analysis. An overload risk, a voltage out-of-limit probability and a system instability threshold are quantified through a hierarchical evaluation mechanism, a multi-target optimization constraint condition is formed, and finally a scheduling strategy considering equipment safety, economy and power supply reliability is generated. When the power system operates, intelligent scheduling is carried out according to the operation state of the power grid.

The invention relates to the technical field of automatic control, and discloses a PID (Proportion Integration Differentiation) intelligent pressure reducer controller, which comprises the following steps of: judging whether an environment disturbance or a load sudden change event exists according to a system load change rate and sensor feedback stability, constructing a master control-controlled coupling characteristic matrix by adopting a dual-channel data fusion method, performing attribution splitting on each disturbance channel, and obtaining a PID (Proportion Integration Differentiation) intelligent pressure reducer. PID parameters are dynamically adjusted according to the principal component weight of a disturbance channel, a variable parameter PID adjustment matrix is constructed, filtering smoothing is carried out on sampled signals through an extended Kalman filtering algorithm, a feedback closed-loop correction vector based on sampling residual errors is constructed, a historical offset tracking and switching value boundary judgment mechanism is introduced, fine tuning suppression is carried out on control signals of a motor driving mechanism, and the control signals of the motor driving mechanism are output. Judging whether a mechanical limiting protection device needs to be activated or not; and if yes, automatically triggering voltage limiting protection logic and locking the current control quantity. The method has the advantage of improving efficient and stable operation.

The invention discloses an overhead line-high voltage cable sheath lightning stroke induced voltage calculation method. At present, the voltage of a lightning stroke point, a connection point of an overhead line and a cable and a point in a well of each joint along a cable sheath cannot be obtained at the instantaneous moment of lightning stroke of the overhead line on site. According to the method, electromagnetic transient simulation modeling is carried out on actual spatial positions, structural parameters and material parameters of field overhead lines and high-voltage cables, electromagnetic transient simulation modeling is carried out on lightning currents, electromagnetic transient modeling is carried out on normal operation conditions and actual lightning stroke fault conditions of an electric power system, and after the randomness of the fault occurrence moment is considered, the electromagnetic transient simulation modeling is carried out on the actual lightning stroke fault conditions of the electric power system. And the maximum lightning stroke induced voltage value of each point along the cable sheath after lightning stroke is calculated through electromagnetic transient simulation software, so that a reference basis is provided for insulation matching design of the cable sheath of the overhead line-cable mixed line invaded by lightning current, and a foundation is laid for design evaluation of various subsequent voltage limiters and protectors.

To generate a charging path for a battery, a method includes generating simulation data for charging currents based on a battery model indicating an internal state of a battery, generating an initial look-up table (LUT) for the charging currents and preset battery voltage limits based on the simulation data, the initial LUT representing initial charging limit conditions of the battery for stages corresponding to the charging currents, generating a modified LUT by adjusting at least one of the initial charging limit conditions of the initial LUT, in response to the initial LUT failing to satisfy a threshold, determining a final LUT based on the modified LUT, in response to the modified LUT satisfying the threshold, and generating a charging path for the battery based on the final LUT.

The invention discloses a feedback field weakening control method and system for a surface-mounted permanent magnet synchronous motor, and the method comprises the steps: collecting a rotation speed feedback value of a motor, and controlling the operation of the motor through employing a maximum torque current ratio if the rotation speed feedback value is smaller than a rated rotation speed; calculating a first flux-weakening rotating speed according to the real-time load rate and the bus voltage fluctuation, and if a rotating speed feedback value of the motor is greater than the first flux-weakening rotating speed, entering a first flux-weakening mode: calculating a difference value between an output voltage amplitude and the bus voltage, generating a d-axis current compensation value, and performing load compensation and rotating speed compensation on the d-axis current compensation value to obtain a d-axis current given value; the maximum value of the q-axis current is calculated, given voltage values of the d-axis and the q-axis are generated, and the motor is driven to operate; and calculating a second flux-weakening rotating speed according to the q-axis current maximum value and the voltage margin, and if the rotating speed feedback value of the motor is greater than the second flux-weakening rotating speed, entering a second flux-weakening mode: further limiting the q-axis current maximum value through a current limit circle and a voltage limit circle on the basis of the first flux-weakening mode.

The invention discloses a voltage out-of-limit control method and system for grid connection of a photovoltaic power generation system containing energy storage, and the method comprises the steps: building a grid connection model according to an equivalent structure diagram of grid connection of the photovoltaic power generation system containing energy storage; according to the grid-connected model, under the conditions that the line impedance is fixed and the load power is random and uncontrollable, the voltage of a grid-connected point is adjusted by controlling active power and reactive power output by an inverter; a dynamic participation factor is introduced, and the charge state of energy storage and the residual capacity of an inverter are taken into reference so as to carry out self-adaptive distribution of power. The method can effectively solve the problems of insufficient adjustment and response lag of a current power distribution network voltage out-of-limit control strategy.

The invention belongs to the related technical field of motor control, and discloses a permanent magnet synchronous motor field weakening control method and device fusing current feedforward and model prediction control, and the method comprises the steps: (1) building a multi-objective optimization function based on a torque tracking error, current fluctuation and voltage limitation of a permanent magnet synchronous motor, solving the multi-objective optimization function through an interior point penalty function and a Newton iteration method based on a feedforward instruction torque and a model prediction control instruction torque to obtain an optimal current pair of the permanent magnet synchronous motor; (2) constructing a field weakening control fusion model based on the obtained optimal current pair, the feed-forward instruction torque and the model prediction control instruction torque; and (3) fusing the feedforward instruction torque and the model prediction control instruction torque through the dynamic weight factor of the flux-weakening control fusion model, and obtaining a flux-weakening control instruction of the permanent magnet synchronous motor in combination with the optimal current pair, thereby realizing flux-weakening control of the synchronous permanent magnet motor. The method has a multi-target cooperation capability.

The invention discloses an MPC-SP-based all-vanadium redox flow battery constant-power charging and discharging control method, which is applied to an energy storage control system composed of an MPC-SP controller, a PCS and an all-vanadium redox flow battery, and is characterized in that the controller dynamically and accurately adjusts the power output to the battery based on preset SOC interval division, and the power output to the battery is increased along with the increase of the actual SOC value of the battery. The power is increased in stages. Meanwhile, the controller pays attention to the voltage Ud of the battery end all the time, and when the Ud reaches a voltage limiting value, the constant voltage mode is switched, so that the battery is effectively prevented from being damaged due to overhigh voltage. The state-based dynamic power management is much safer, more flexible and more intelligent than traditional fixed constant power control. According to the invention, the change rate of current in the charge-discharge process of the all-vanadium redox flow battery can be reduced, the service life of the battery is prolonged, and the safety is guaranteed.

The invention relates to the technical field of welding, and provides a low-load voltage circuit and a lithium battery welding machine. The circuit comprises a main control module, a voltage detection unit, a switching circuit, a pulse modulation unit and a current sampling feedback unit. The voltage detection unit monitors the end voltage of a welding gun of a welding machine in real time, the switching circuit limits the output voltage to be smaller than a safety threshold value of 36 V in a no-load mode, and a built-in bidirectional thyristor achieves isolation of a high-voltage loop and a low-voltage loop. The pulse modulation unit adjusts the on-off frequency of a main power loop, and the current sampling feedback unit dynamically adjusts the pulse duty ratio so as to accurately control the welding current. The lithium battery welding machine integrates the circuit and is provided with a welding gun assembly, a main transformer and a power supply module, the electric shock risk is effectively reduced, and the welding quality and efficiency are improved.

The invention discloses a current prediction control method based on a permanent magnet synchronous motor. A control system of the permanent magnet synchronous motor comprises a storage unit in which various parameter tables are preset; the control method comprises the following steps: performing temperature prediction according to current sampling data; dividing a temperature operation interval, judging the temperature operation interval according to the predicted temperature prediction value, and carrying out current amplitude limiting; unifying various temperature limiting amplitudes and voltage limiting amplitudes, establishing constraint conditions of the permanent magnet synchronous motor, and converting equality constraints into a target function through the constraint conditions; eliminating a voltage inequality constraint and a dynamic current inequality constraint in the target function; and finally, calculating to obtain a current reference value at the next moment, and processing the current reference value by the inner loop controller to output a switching signal to the inverter. The control system can adjust constraint conditions and objective functions on line according to actual working conditions such as temperature and motor parameter changes, and robust control over environment disturbance and non-linear influences is achieved.

Disclosed are a flyback switching power supply and a self-powered circuit and method therefor. The self-powered circuit includes: a charging capacitor configured to draw power from a primary coil and supply power to a switching power supply chip; a withstand voltage switch tube for acquiring a power supply voltage of the primary coil and outputting a charging voltage; a charging switch tube for controlling whether to charge the charging capacitor; an adjustment control tube for limiting the charging voltage of the charging capacitor; a voltage limiting control unit for controlling the conduction state of the adjustment control tube according to the charging voltage; a charging control unit preset with a charging requirement; and an inverter for acquiring the conduction switch signal and controlling the voltage limiting control unit or the charging control unit to be connected to the adjustment control tube according to the conduction switch signal.

The invention discloses a power switch MOS tube driving power supply protection circuit, and the circuit comprises a driving amplitude detection module which is used for sampling and monitoring the voltage swing of power switch MOS tube driving power supply in real time; the driving amplitude limiting module is configured to be used for limiting the voltage swing which is externally provided for driving and supplying power to the power switch MOS tube, so that the voltage swing does not exceed a preset threshold value; and the driving amplitude response module is used for receiving and processing the control signal of the driving amplitude detection module and outputting a feedback signal with loading capacity to the inside and the outside simultaneously. When the swing of the power supply voltage externally provided for the power switch MOS tube drive is unstable, the drive amplitude detection module is used for sampling and detecting the power supply voltage in real time, and then the drive amplitude response module is used for processing signals and feeding back whether the power supply information meets the protection action triggering requirement or not to the outside. And meanwhile, reasonable voltage limiting protection measures are implemented through the driving amplitude limiting module, so that the safe operation of the power switch MOS tube is ensured.

The invention discloses a direct-current solid-state circuit breaker with a voltage limiting protection circuit and a control method thereof. The direct-current solid-state circuit breaker comprises a solid-state switch module, the solid-state switch module comprises a first sub-module and a second sub-module which are the same, and each of the first sub-module and the second sub-module comprises a SiC JFET device J, capacitors C, Cgd and Cgs, a comparator U, an MOSFET device Q, a resistor Rg and resistors ra and rb; the first end of Rg is used for receiving a driving signal, and the second end of Rg is connected to the grid electrode of J after being connected with the first end of C, the second end of Cgd and the first end of Cgs; the second end of ra and the first end of rb are connected as a comparison voltage sampling point; the first end of ra is connected to the first end of Cgd and the drain electrode of J; the second end of the rb is connected to the second end of the Cgs, the source electrode of the Q and the source electrode of the J; the second end of C is connected to the drain electrode of Q; the output end of U is connected to the grid electrode of Q; the anode input of U is comparison voltage, and the cathode input is reference voltage; the source electrode of the first sub-module J is connected to the drain electrode of the second sub-module J.

Circuits and methods are provided for an input hysteresis buffer that includes a voltage limiting unit, a voltage detecting unit connected to the voltage limiting unit, and a supply tracking bias unit connected to the voltage detecting unit. The voltage liming unit comprises a first voltage limiting unit and a second voltage limiting unit. The voltage detecting unit comprises a first voltage detecting unit configured to detect the presence of a first threshold voltage in an input signal, and a second voltage detecting unit configured to detect the presence of a second threshold voltage in the input signal. The supply tracking bias unit is configured to supply a control signal to the voltage detecting unit.

The invention discloses a control method for limiting photovoltaic output voltage, current and power, relates to the technical field of photovoltaic converter control strategies, and solves the problems of overlarge photovoltaic output voltage and current, excessive power and overlarge output voltage of a converter under specific requirements. According to the technical scheme, the method is characterized in that control under an MPPT mode, a power limiting mode and a converter output voltage limiting mode is converted into control over inductive current, the minimum value is selected as an inductive current given value, and therefore automatic switching under all the modes is achieved; wherein the power limiting mode can limit the photovoltaic output power according to the frequency change of the power grid to realize the primary frequency modulation of the power grid; and an MPPT restarting strategy is provided for solving the problem that the system cannot recover the MPPT mode due to sudden change of the power of the photovoltaic panel, so that the power of the system cannot be continuously tracked.

The invention belongs to the technical field of flexible macro-micro drive motion system preset output tracking control, and particularly relates to a flexible macro-micro drive motion system preset output tracking control method based on active disturbance rejection, which specifically aims to estimate and compensate multi-modal vibration caused by a flexible hinge, an elastic structure and the like in real time through a linear extended state observer (LESO); the influence of high-frequency resonance on the system stability is reduced; an anti-saturation compensator is introduced to dynamically adjust the control quantity, the output saturation problem of the piezoelectric stack caused by input voltage amplitude limiting is avoided, and the physical realizability of a control instruction is ensured; and in combination with a preset performance function and a dynamic surface method, a tracking controller giving consideration to both transient response and steady-state precision is designed, and meanwhile, an LMI optimization control distribution strategy is utilized to coordinate the cooperative action of a macro-micro actuator under saturation constraint, so that the uncertainty of the system to the model and the robustness of the system to external disturbance are enhanced.

An adapter for introduction into a two-conductor line comprises an adapter housing; and, arranged in the adapter housing, an adapter electronics that connects a first terminal with a third terminal using a first connecting line and a second terminal with a fourth terminal using a second connecting line, wherein the adapter electronics further includes an overvoltage protection system designed to limit a voltage applied across the third and fourth terminals to a first maximum value in the event of failure; an overcurrent protection system adapted to prevent a rise of the loop current above a maximum electrical current value in the event of failure; and a circuit adapted in the non-failure case to control a voltage applied to the overvoltage protection system, from a minimum input voltage, to a second maximum value lower than the first maximum value.

The invention discloses a grid-connected distributed photovoltaic inverter control method and system. The method comprises the following steps: selecting a first control object, and establishing a first controller based on the first control object; establishing a first equivalent control signal, and updating the first controller based on the first equivalent control signal to obtain a second controller; and controlling the grid-connected distributed photovoltaic inverter according to the second controller. Through the control method, the power grid operation state change when the voltage of the power grid drops can be effectively handled, and the stability and reliability of the grid-connected distributed photovoltaic inverter are improved. When the voltage of the power grid drops, the voltage of the direct current link capacitor is kept constant, so that the voltage of the direct current link can be prevented from exceeding the voltage limit of the capacitor, and the off-network phenomenon caused by triggering the protection device is avoided.

The invention provides a data center micro power supply capacity optimization method and system. The method comprises the following steps: constructing a corresponding three-dimensional constraint parameter group in real time according to real-time working parameters; obtaining a first correlation coefficient between the power balance parameter and the equipment capacity parameter through linear correlation, obtaining a second correlation coefficient between the equipment capacity parameter and the voltage limiting parameter through nonlinear correlation, and obtaining a third correlation coefficient between the voltage limiting parameter and the power balance parameter through mapping correlation; obtaining a power output predicted value of the photovoltaic micro-grid, and constructing a corresponding capacity optimization function in real time in combination with the first correlation coefficient, the second correlation coefficient and the third correlation coefficient; and performing optimization processing on a preset particle swarm algorithm to generate a corresponding target optimization algorithm, and solving the capacity optimization function through the target optimization algorithm to output a corresponding photovoltaic capacity optimization value in real time. According to the method, the capacity of the photovoltaic micro power supply can be objectively and dynamically optimized, and the optimization efficiency is improved.

The invention discloses a field weakening control method and device of a motor, a storage medium and a vehicle, and the method comprises the steps: determining and inputting an electrical parameter corresponding to a given reference torque of the motor to the motor based on a pre-established current lookup table; when the output voltage of a current controller of the motor exceeds the output voltage limit of an inverter of the motor, determining corresponding motor parameters based on the electrical parameters obtained through real-time monitoring and a pre-established motor parameter lookup table; determining a target included angle based on the electrical parameters and the motor parameters; determining a weak magnetic area where the motor is located based on the target included angle; and based on the weak magnetic area where the motor is located, determining a corresponding electrical parameter correction value, and correcting the electrical parameter to control the output torque of the motor. According to the method, the electrical parameters can be effectively corrected based on the change of the motor parameters, the torque can be accurately output in the flux-weakening acceleration process of the motor, and the torque control precision of the motor under the flux-weakening working condition is improved.

A method and system for protecting a battery power limit, and a storage medium are disclosed. The method for protecting a battery power limit is applied to a vehicle with a battery management system. The method includes: acquiring temperature data, a state of charge, and a cell voltage extreme value of a battery, periodically; calculating a current maximum available power according to the temperature data and the state of charge; determining a power limit coefficient according to the cell voltage extreme value, and a voltage limited power interval corresponding to the temperature data; and obtaining an actual available power that the battery management system allows the vehicle to use according to the maximum available power and the power limit coefficient. According to the method, different temperature ranges can be adapted according to logic.

The invention belongs to the technical field of impact current suppression, and relates to a method and system for suppressing the impact current of a DC bus output by a DC charger, and the method comprises the following steps: collecting the output voltage of the DC bus and the required voltage of a vehicle side, and forming a voltage sequence; calculating the change rate and the pressure difference of the two; when the change rate exceeds a threshold value or the communication time sequence is discontinuous, entering voltage limiting constraint control; determining a limiting function according to the change rate and the voltage difference and updating a voltage reference value; adjusting the output voltage according to the updated reference value; and continuously executing voltage reference value updating and output adjustment until the output and the required voltage tend to be consistent, then exiting the voltage limiting constraint, and continuously performing dynamic adjustment according to the required voltage. According to the technical scheme, through dynamic monitoring and voltage difference constraint on the bus and the required voltage, voltage limiting adjustment and reference value smooth updating during sudden change are achieved, the impact current peak value is effectively restrained, and it is ensured that the voltage is stable, the current is limited, and the system operates stably.

A power supply control method, a power supply and a computer program product are applied to the technical field of power supplies, and the power supply control method comprises the following steps: obtaining a target output value and a target limit value of a current configuration; acquiring a voltage value measured by the current circuit and a current value measured by the current circuit; if the source working mode is satisfied, determining a feedback time relationship between the current loop control module and the voltage loop control module; if the feedback time of the current loop control module is less than the feedback time of the voltage loop control module, controlling to reach a current limit value or a current output value in the target output value and the target limit value; and on the contrary, the voltage loop control module controls to reach the voltage limit value or the voltage output value in the target output value and the target limit value. Because the control module with short feedback time can be switched to control the power supply output, the voltage switching and the current switching can be smoothly carried out, thereby avoiding the occurrence of overtuning and inflection points.

The invention discloses a power distribution network voltage regulation and control method and system based on a multi-agent strategy gradient, and the method comprises the steps: carrying out the modeling of a photovoltaic inverter and energy storage equipment, obtaining an agent, and configuring an Actor-Critic network architecture in the agent; obtaining a local observation feature of the intelligent agent, and inputting the local observation feature into an online Actor network to obtain a current execution action; evaluating the current execution action through the Critic network to obtain a current prediction reward; updating the weight of the online Actor network in real time according to the current predicted reward; inputting the current execution action of each agent into a power distribution network voltage control model to obtain a system reward and a power distribution network system state; and updating the weight of the online Critic network according to the system reward and the state of the power distribution network system. According to the method, distributed multi-agent collaborative optimization is adopted, the voltage out-of-limit rate and the network loss are reduced, and the robustness and adaptability of the algorithm in a complex environment are improved.

The invention discloses a bidirectional direct current circuit breaker which comprises an electronic branch assembly, a voltage limiting branch assembly and an energy consumption branch assembly. The electronic branch assembly is used for transferring current; the voltage limiting branch assembly is electrically connected with the electronic branch assembly in parallel so as to reduce the turn-off overvoltage of the circuit breaker; and the energy consumption branch assembly is electrically connected with the electronic branch assembly in parallel so as to be used for absorbing the energy of the circuit. According to the hybrid DC circuit breaker, the current transfer function of the hybrid DC circuit breaker can be realized through the electronic branch assembly, the voltage limiting branch assembly and the energy consumption branch assembly. Compared with a bidirectional direct-current circuit breaker based on a power electronic device in the related technology, the bidirectional direct-current circuit breaker is compact in structure, low in connection inductance and high in universality, and functional units can be configured. The problems that in the related technology, connection is complex, redesign is needed under different working conditions, and functional units are inconvenient to adjust are solved.

The invention discloses a torque ripple suppression method for a permanent magnet synchronous motor under a limited voltage, and belongs to the technical field of power generation, power transformation or power distribution. The method comprises the following steps: acquiring torque data changing along with a rotor position under different excitation currents, and establishing a torque three-dimensional look-up table model of the torque about a shaft current and the rotor position; respectively establishing optimization targets for a low-rotating-speed working condition and a high-rotating-speed working condition, and establishing a stator current two-dimensional table look-up model under the low-rotating-speed working condition and a stator current three-dimensional table look-up model under the high-rotating-speed working condition in combination with the torque three-dimensional table look-up model; an optimized stator current algorithm model is established according to the stator current look-up table model, the stator current two-dimensional look-up table model or the stator current three-dimensional look-up table model is switched according to the criterion of direct current voltage out-of-limit, and the query value of the optimized stator current is used as a stator current reference value for vector control of the permanent magnet synchronous motor. While low-speed copper loss reduction and high-speed speed regulation range expansion are taken into consideration, overall torque harmonic suppression under a voltage limited working condition is realized.

A power supply control method, power supply, and computer program product are applied to the power supply technology field. The power supply control method includes: obtaining a currently configured target output value and a target limit value; obtaining a currently measured voltage value and a currently measured current value of the circuit; if a source operating mode is satisfied, determining the feedback time relationship between a current loop control module and a voltage loop control module; if the feedback time of the current loop control module is less than the feedback time of the voltage loop control module, controlling the current to reach the current limit value or current output value between the target output value and the target limit value; otherwise, controlling the voltage to reach the voltage limit value or voltage output value between the target output value and the target limit value based on the voltage loop control module. Because the power supply output can be controlled by switching to a control module with a shorter feedback time, voltage and current switching can be performed smoothly, thereby avoiding overshoot and inflection points.

The invention relates to the field of explosion-proof electrical technology, and discloses an intrinsically safe output Ethernet transmission circuit, which comprises an Ethernet physical layer transceiver chip U6, a network transformer U7, an electrostatic protection diode D17, an electrostatic protection diode D18, voltage stabilizing diodes D13-16, capacitors C46-62, resistors R42-45, resistors R59-65, thick film resistors R74-77, fuses F1-4, a safety Y capacitor CY1, an inductor L2, a gas discharge tube TV1, a gas discharge tube TV2 and an RJ45 connector RJ1. The intrinsically safe output Ethernet transmission circuit provided by the invention realizes 3000V voltage isolation, has the characteristics of low cost and easiness in implementation, not only has strong anti-interference and lightning surge protection capabilities and stable transmission performance, but also is easy to calculate and check intrinsically safe parameters through multi-stage isolation and current-limiting and voltage-limiting protection, and has a wide application prospect. And multiple key problems in intrinsic safety Ethernet transmission are effectively solved.