27 results about "Power factor control" patented technology

The invention relates to the technical field of photovoltaic power station intelligent monitoring, and discloses a distributed photovoltaic power station monitoring management method and system based on a cloud platform, and the method comprises the steps: collecting the operation parameters of a photovoltaic string; applying bounded perturbation in a stable interval of maximum power point tracking to obtain a feature vector; and constructing a topological graph, and reconstructing a virtual current and voltage characteristic curve and key characteristic points. And obtaining a node-level health index on the topological graph, and generating an abnormal score in combination with the reference distribution. And according to the shape deviation of the virtual current and voltage characteristic curve and the distribution of the node-level health indexes, positioning an abnormal string and an affiliation node thereof, solving the optimization problem of power generation income, degradation risk and power fluctuation under the condition of satisfying parameter constraints, and obtaining an active power limit and a power factor control track to be issued to an edge node for execution. According to the invention, the diagnosis precision and the grid-connected stability of the distributed photovoltaic power station in a large-scale scene are improved, and the expandability and the intelligent level are improved.

An electric motor is provided. The electric motor includes a motor controller configured to convert AC power to a variable frequency variable voltage power for driving the electric motor according to a commanded motor output. The motor controller includes a PFC circuit configured to control a power factor of the electric motor and a microcontroller coupled to the PFC circuit and configured to activate the PFC circuit when the commanded motor output is greater than a threshold motor output, deactivate the PFC circuit when the commanded motor output is less than or equal to the threshold motor output, and generate a control signal based on the commanded motor output. The motor controller further includes an inverter configured to receive the control signal and generate the variable frequency variable voltage power according to the commanded motor output.

The invention discloses a control method and device applied to a totem pole PFC. The method comprises the steps of obtaining an alternating current input voltage and an instantaneous current in real time; dividing a normal working mode, a dead zone transition mode and a soft start mode according to a comparison result of the alternating current input voltage and a first preset voltage threshold value and a comparison result of the instantaneous current and a first preset current threshold value; and correspondingly adjusting the opening and closing of the high-frequency bridge arm and the power-frequency bridge arm according to a normal working mode, a dead-zone transition mode and a soft start mode. According to the invention, a traditional single control mode is replaced, an accurate and differentiated control strategy is provided for the zero-crossing region, and refined and programmed management of the zero-crossing process is realized.

The invention discloses an on-site two-stage voltage control method and system based on optical storage integrated equipment, and belongs to the technical field of intelligent power distribution, and the method comprises the steps: obtaining the grid-connected point voltage and equipment operation parameters of the optical storage integrated equipment, calculating the reactive voltage sensitivity of the grid-connected point, and constructing a dynamic weight coefficient model; a dynamic reactive voltage droop curve slope is obtained, and a reactive voltage droop curve control function is optimized; according to the optimized reactive voltage droop curve control function and the fixed power factor control function, carrying out first-stage adjustment on the grid-connected point voltage; and if the voltage of the grid-connected point still exceeds the preset threshold value after the first-stage adjustment is performed on the voltage of the grid-connected point, performing active power reduction control, and performing second-stage adjustment on the voltage of the grid-connected point. The method can effectively solve the limitation of the light-storage integrated equipment in the aspect of reactive power regulation in the prior art, improves the efficiency and accuracy of voltage regulation of the power distribution network, and guarantees the safe and stable operation of a power system.

The invention relates to the technical field of new energy charging, and discloses a power self-adaptive charger based on cogeneration and topology reconstruction, the output end of a DC / DC power module and the output end of a TEG are connected in parallel to a direct current bus, so that waste heat generated by the DC / DC power module is directly converted into direct current electric energy of the direct current bus, and the direct current electric energy of the direct current bus is converted into direct current electric energy. Waste heat in the high-power charging process can be effectively recycled, heat dissipation energy consumption can be further reduced, the central controller can control the DCA to be switched to the corresponding power buffer mode or reactive compensation mode in a capacitor topology reconstruction mode according to the vehicle battery demand power in combination with the real-time power grid voltage and the real-time power factor, and the power consumption can be reduced. Compared with the prior art, the self-adaptive adjustment of the overall power can be realized through the switching of the working modes of the charger, and a reactive compensation cabinet or a peak energy storage cabinet does not need to be additionally arranged, so that the diversified scene requirements of the charger can be met, the energy efficiency of the charger can be improved, and the application cost can be greatly reduced.

The invention discloses a railway multi-source input type power supply and power grid side bidirectional AC / DC converter control method, and relates to the technical field of rail transit power supply. The power supply architecture takes an alternating-current power grid as a main power supply and takes wind power, photovoltaic and lithium batteries as standby power supplies, and each energy source is accessed to a direct-current power bus through a corresponding converter; a super capacitor and a converter are introduced to realize lithium battery energy management and bus voltage disturbance suppression, a multi-machine parallel unidirectional DC / AC converter is adopted to supply power to a used load, and a bypass switch is arranged to realize direct power supply backup of a power grid. According to the converter, a double-loop control loop is constructed under a dq0 rotating coordinate system, a rectification mode, a grid-connected inversion mode and a local load inversion mode are switched according to the state of a power supply system, and network side current unit power factor control, new energy excess energy feedback and load uninterrupted power supply under a fault are achieved. The system improves the power supply reliability, assists in new energy consumption, and is suitable for a power supply system used by a first-level load such as railway signal and communication.

The invention relates to the technical field of intelligent power grid operation control, and discloses a photovoltaic power station intelligent control method and system based on big data, and the method comprises the steps: obtaining temperature distribution characteristics; determining a performance change trend, and performing dynamic compensation according to the performance change trend to obtain a preliminary adjustment signal; self-adaptive optimization judgment is carried out, and a self-adaptive optimization instruction is generated; the optimal control parameters are predicted, real-time updating is carried out according to the optimal control parameters, and the updated power generation efficiency is obtained; performing expected judgment on the power generation efficiency, and extracting residual data in a system log to obtain a refined performance association rule; and S12, updating the performance mapping model, and returning to the step S12 until the power generation efficiency exceeds a preset efficiency value, thereby obtaining the normally operating system. According to the method, the performance change of the photovoltaic module can be accurately sensed and the power factor control parameters can be adaptively adjusted under the dynamic temperature change of the photovoltaic power station.

The invention discloses a nonlinear control method and device for a permanent magnet synchronous motor-converter system, and belongs to the technical field of permanent magnet synchronous motor control, and the method comprises the steps: designing the control rate of d-axis and q-axis currents of a permanent magnet synchronous motor based on a unity power factor control target; completing the design of a parameter adaptive controller of the control rate of d-axis and q-axis current based on a unity power factor control target; obtaining an estimation function expression of the q-axis inductance of the permanent magnet synchronous motor changing along with the actual d-axis and q-axis current values of the permanent magnet synchronous motor; correcting the control rate of the d-axis current and the q-axis current of the unity power factor control target obtained in the step 2 according to the obtained inductance change rule; and closed-loop control of the permanent magnet synchronous motor is completed. The unity power factor operation effect that the output reactive power of the permanent magnet power generation system is zero is achieved, and the active power density of the permanent magnet power generation system is improved.

The invention discloses a power grid adaptive direction distance protection method and system based on an apparent power supply, and the method comprises the steps: building a home terminal dynamic equivalent apparent power supply model based on a voltage phasor and a current phasor obtained through measurement at a protection installation part, and enabling the model to be defined by two key parameters, namely, an apparent power supply voltage amplitude and equivalent impedance; three-phase voltage and three-phase current at a protection installation position are collected in real time, positive sequence voltage is calculated through a symmetrical component method, and the real-time phase difference between the dynamic equivalent apparent power source at the terminal and the three-phase voltage and the three-phase current is calculated; comparing the real-time phase difference with a preset action interval; when the real-time phase difference is in a set action interval, judging that a fault is a forward fault, and starting a protection action; and otherwise, a reverse fault is determined, and latching protection output is carried out. According to the method, the dependence of traditional protection on fixed source impedance parameters is effectively overcome, multiple control strategies such as unit power factor control, low voltage ride through and negative sequence current suppression of the wind turbine generator are adaptively compatible, and the interference of harmonic waves and power fluctuation on protection is remarkably suppressed.

Topology of an isolated rectifier power converter, and a power factor control method, which belong to the technical field of power electronics. The topology comprises a voltage source, a rectifier circuit, a power conversion unit and a drive control circuit. The power conversion unit comprises n power conversion circuits connected in parallel. Each power conversion circuit comprises a clamping transistor, a transformer, a primary-side switching transistor and a secondary-side switching transistor, wherein a clamping transistor of an ith power conversion circuit is an active clamping transistor, and clamping transistors of the remaining (n-1) power conversion circuits are passive clamping transistors. The drive control circuit is used for determining a target on-time and target duty cycle of each primary-side switching transistor within one switching cycle, and generating, on the basis of the target on-time and the target duty cycle, a drive control signal for controlling each primary-side switching transistor, wherein under the action of the drive control signal, the waveform of an input alternating current flowing through the voltage source is consistent with the waveform of an alternating voltage.

The invention relates to a large current generating device and current transformer verification equipment, and relates to the field of extra-high voltage power supply equipment, and the large current generating device comprises a three-phase rectification unit, an IGBT full-bridge conversion unit, an isolation conversion transformer, a rear-end capacitance compensation unit and a control feedback unit. The three-phase rectification unit can convert three-phase alternating current into direct current, the IGBT full-bridge conversion unit is connected with the three-phase rectification unit and can convert the direct current into single-phase alternating current, and the input end of the isolation conversion transformer is connected with the IGBT full-bridge conversion unit and can increase the current of the single-phase alternating current and output large-current alternating current. The rear-end capacitance compensation unit is connected to the output end of the isolation conversion transformer to improve the power factor of the large-current alternating current, and the control feedback unit is arranged between the output end of the isolation conversion transformer and the IGBT full-bridge conversion unit, so that the output current can be improved, and the weight and the cost of the device can be reduced.

The application provides a distributed power balancing and voltage regulating method for a current control type converter cluster. The method belongs to the field of micro-grid control, and is based on reactive voltage droop and voltage amplitude control to generate a reference current amplitude of the parallel converter, so that each parallel converter outputs the same current amplitude; meanwhile, the phase of the current vector is determined by four-quadrant power factor control, so as to ensure that the output currents among the parallel converters are in the same phase state, and the load side currents are effectively superimposed and the maximum load current is obtained. In view of the harmonic problem caused by the access of a nonlinear load, the application further adopts harmonic virtual impedance control at a fundamental frequency and selected harmonic frequencies, and combines with the multi-resonance controller adjustment of the current loop to effectively reduce the amplitude of the equivalent harmonic impedance of the DG unit, so that the harmonic circulating current among the DGs is minimized, and the power quality at the point of common coupling (PCC) is improved.

The invention provides a charging device of a vehicle-mounted host and a vehicle. The input end of a control module is connected with a power factor correction module and a DC-DC change module through a sampling module so as to collect electric data of the power factor correction module and the DC-DC change module; the output end of the control module is connected with the control end of the switch of the power factor correction module and the control end of the switch of the DC-DC change module so as to adjust the voltage value output to the vehicle-mounted host according to the collected electric data. Compared with a traditional power factor simulation control method, the digital circuit is combined with voltage and current double-loop control, the control process is completed through the DSP, the defects that a simulation control system is single in circuit function and low in control precision are overcome, the anti-interference capacity is high, reliability is high, and complex control can be achieved.

The invention discloses a single-stage AC-DC converter control method, system, device and equipment and a storage medium, and belongs to the field of electric energy conversion, and the method comprises the steps: simplifying a duty ratio expression according to a whole power factor control strategy, and obtaining a simplified conduction duty ratio; determining a Taylor expansion point according to the simplified conduction duty ratio to obtain theoretical conduction time; timing is started from the switch conduction moment of the current switching period until demagnetization is detected to be finished, counting is carried out, a predicted value of the next switching period is obtained, and a conduction time predicted value of the next switching period is determined based on the theoretical conduction time; and determining the conduction time correction based on output voltage closed-loop control, and superposing the conduction time predicted value of the next switching period and the conduction time correction to obtain the final switching conduction time so as to realize control of the single-stage AC / DC converter. According to the invention, the equivalent switching frequency can be improved, the power density of switching power supply products is improved, the device stress is reduced, and the model selection cost is reduced.

The invention relates to the technical field of metro power supply system operation modes, in particular to a sharing-based metro power supply system operation method, and provides a reactive compensation scheme of a metro power supply system under the background of resource sharing of a main substation. The minimum reactive power compensation amount before and after resource sharing of the main substation under the condition that the PCC full-day power factor reaches the standard is calculated, and a reactive power compensation scheme comprising various reactive power compensation devices is provided. According to the scheme, on the basis that the minimum reactive power compensation amount before and after main substation resource sharing meets the compensation requirement, the installation capacity of the SVG and the electric reactor or the capacitor is determined with the minimum SVG capacity as the target, and the investment cost of a power supply system is reduced.

The invention provides a photovoltaic grid-connected power factor treatment and voltage treatment device and method. The device is installed in a factory power distribution network system, and the factory power distribution network system comprises an on-load voltage regulating transformer, a transformer comprehensive automatic device, a photovoltaic wire inlet cabinet, a reactive compensation cabinet, a voltage transformer cabinet and a load wire outlet cabinet. The photovoltaic grid-connected power factor treatment and voltage treatment device comprises a controller, a two-way metering ammeter and three groups of one-way metering ammeters, the controller is in signal connection with the two-way metering electricity meter, the three sets of one-way metering electricity meters, the transformer comprehensive automatic device and the voltage transformer cabinet through control wires. According to the invention, metering data of each metering ammeter and bus voltage data of a voltage transformer are extracted to calculate and control putting and removing of a capacitor, adjust a power factor, control an on-load voltage regulating transformer to adjust a tap position and adjust a transformation ratio, and the problems of low factory power factor and standard exceeding of low-voltage bus voltage rise are solved in a linkage manner. And factory power quality is improved.

The application discloses a kind of photovoltaic grid-connected system incoming line power factor control method and system.In the present application, firstly, the judgment accuracy of power factor change trend is improved in prediction link.Light intensity, load power and other key variables are included in the model, and the dynamic correlation of power factor, light change and load power consumption is analyzed synchronously.The correlation is captured and learned by the model.Therefore, when predicting future power factor, the interaction of multiple factors in actual operation can be considered more comprehensively, the prediction result is closer to the real trend, the system can predict the change direction of power factor in advance, and the mode of passive response problem of traditional method is changed, the flexibility and stability of regulation are strengthened in compensation link.The calculation of adaptive reactive power compensation quantity is not only based on future prediction value, but also dynamically adjusts the compensation strength according to the accuracy of historical prediction, which also prevents resource waste caused by excessive compensation, and effectively improves the stability and reliability of system operation.

A method and system for controlling a photovoltaic solar power generation source operatively coupled to a power grid system at a point of common coupling (PCC) to perform a plurality of dynamic reactive power control based functions including: reactive power set point control, power factor control, and voltage control, when its primary energy source is not available, and available. Voltage control may also prevent PCC voltage from violating a voltage limit caused by real power generation from itself or by real power generation from an additional distributed power generation source operatively connected to said power grid system, or by both. Controlling a battery energy storage based distributed power generation source operatively coupled to a power grid system at a PCC to perform reactive power set point control, power factor control, and voltage control, during both the conditions when its primary energy source is not available, and available is also provided.

The invention belongs to the technical field of current transformer load test, and particularly relates to a current transformer load test device based on a PI regulator and a control method thereof, and the device comprises a DC power supply module, a PWM inversion module, an LCL voltage stabilization filtering module and a PWM rectification feedback module. An energy closed-loop path is constructed through a PWM rectification feedback module, a three-phase full-control MOSFET bridge and a unit power factor control strategy (setting q-axis modulation voltage Vgq = 0) are adopted, and a PI regulator with a proportionality coefficient Kp1 = 1.0 and an integral coefficient Ki1 = 0.8 is matched to accurately regulate grid-side d-axis current igd, so that rectification-side current and voltage are in the same phase, and the synchronous rectification efficiency is greatly improved; meanwhile, feedback energy is buffered through a direct-current bus capacitor Cdc, impact of energy fluctuation on a direct-current bus is avoided, and finally electric energy originally dissipated in a load test is efficiently fed back to the direct-current power supply module.

The application provides a current-mode PWM rectifier and a passive control method thereof, comprising a filter unit, a rectifier unit and a load unit connected in sequence; an input end of the filter unit is connected with a three-phase AC source, an output end of the filter unit is connected with an input end of the rectifier unit, a first output end of the rectifier unit is connected with an input end of the load unit, and a second output end of the rectifier unit is connected with an output end of the load unit; the filter unit is used for filtering high-order harmonics of the three-phase AC source received by the current-mode PWM rectifier on an AC side; the rectifier unit is used for rectifying a filtered voltage to obtain a rectified voltage; and the load unit is used for converting the received rectified voltage to realize energy output. The application can realize independent decoupling control of active power and reactive power and unit power factor control, can also be used for reactive power compensation function, and has the advantages of few control parameters, convenient debugging and strong anti-interference capability.

The present disclosure provides an air conditioner for improving a power factor. The air conditioner comprises: an inverter used to drive a motor; a load including the inverter; a power conversion circuit including a rectifying circuit, which rectifies an input alternating current voltage so as to generate a direct current voltage, and a power factor correction circuit, which supplies an output direct current voltage to the load on the basis of the direct current voltage; and a processor for power factor control of the power conversion circuit. The air conditioner may comprise: a phase estimator for acquiring phase information of the input alternating current voltage; a voltage controller that generates, on the basis of the output direct current voltage and a reference voltage, a first control signal for controlling the magnitude of the output direct current voltage; a partial switching controller that generates setting information for setting a switching period of a switch included in the power factor correction circuit; and a current controller that generates, on the basis of an input current of the power factor correction circuit and a reference current, a second control signal for controlling the switch in the switching period. The reference current can be generated on the basis of the phase information, the first control signal and the setting information.

A power factor control apparatus includes: a phase detection unit configured to detect the phase of an output signal outputted from an inverter, which was originally used to supply electric power to a first electric power supply target, to a second electric power supply target that is different from the first electric power supply target and connected with the inverter and an inverter control apparatus for controlling the inverter; a correction amount calculation unit configured to calculate a phase correction amount based on a power factor command value that is a power factor required by the second electric power supply target; and a correction processing unit configured to generate, based on the phase detected by the phase detection unit and the phase correction amount calculated by the correction amount calculation unit, a power factor control signal for controlling the power factor of electric power supplied to the second electric power supply target and output the generated power factor control signal to the inverter control apparatus.

The invention belongs to the technical field of power factor control, and particularly relates to a power factor control circuit and household equipment. The circuit comprises a rectification module connected to an AC power supply and used for converting AC provided by the AC power supply into DC; a switching device; a load circuit; the controller is configured to obtain a current harmonic value obtained after band-pass filtering processing is carried out on the output current of the rectification module; judging whether the current harmonic value meets a control condition of the switching device or not according to a relationship between the current harmonic value and a preset threshold value; if the current harmonic value meets the control condition of the switching device, the output duty ratio is calculated according to the ratio of the current harmonic value to the preset threshold value, and the control condition of the switching device is the condition for controlling the switching device to be turned on or turned off; and controlling the conduction of the switching device according to the output duty ratio. According to the invention, the electricity utilization stability of the household appliance can be improved.

A power factor control circuit for controlling a PFC circuit is disclosed. The PFC circuit is controlled to operate in one or more operation mode(s) (e.g., CCM, BCM, and DCM) in a single cycle of an input rectified voltage based on a load condition of the PFC circuit. The power factor control circuit includes a control reference circuit and a switching control circuit. The control reference circuit provides a peak current signal, a valley current signal and a turn-on delay signal based on a first current reference, a second current reference, and an input average current. The switching control circuit provides a switching control signal to control a dominant power switch of the PFC circuit based on a current sense signal, the peak current signal, the valley current signal, and the turn-on delay signal.

The utility model discloses an active and reactive power flow allocation system of a multi-source system, which comprises a data acquisition assembly, a plurality of power supply nodes, a plurality of load nodes and a plurality of power transmission lines in the multi-source system, wherein the data acquisition assembly is in circuit connection with the plurality of power supply nodes, the plurality of load nodes and the plurality of power transmission lines; the data acquisition module is used for acquiring real-time data of voltage amplitudes, voltage phases, active power and reactive power of corresponding nodes and lines; the central processing assembly is connected with the data acquisition assembly and receives real-time data; a control signal input end of the power adjusting assembly is connected with a control signal output port of the central processing assembly, is also electrically connected with the plurality of power supply nodes, and adjusts active power output and reactive power output of the plurality of power supplies based on a power control instruction of the central processing assembly; the reactive power compensation assemblies are arranged at the load nodes respectively, the control ends of the reactive power compensation assemblies are connected with the central processing assembly, and power factors of the load nodes are adjusted based on power factor control signals of the central processing assembly.

This electronic device may comprise a display panel, and a power circuit for generating, from an alternating current signal, a power signal to be supplied to the display panel. The power circuit may comprise: a capacitor; a power factor conversion circuit connected to one end of the capacitor so as to control charging of the capacitor on the basis of the power factor of the alternating current signal; a direct current-direct current conversion circuit for generating the power signal on the basis of power charged in the capacitor; and a switching circuit for connecting one end of the capacitor to any one of a resistor or a ground node according to the voltage of the other end of the capacitor.

The invention relates to a reactive compensation control method and device based on operation quadrant recognition, and belongs to the technical field of power system automation and power quality control. Monitoring the flow direction of the active power of the system in real time so as to identify the off-network (first operation mode) or on-network (second operation mode) state; based on different modes, a self-adaptive switching control strategy is adopted, target power factor control is adopted when the power is off the grid, dependence on a real-time power factor is abandoned when the power is on the grid, and direct control with power grid side reactive power zero clearing as a target is switched. The device comprises a signal collector, a processor, a driving circuit and the like and is used for implementing the method. According to the method, the problem that the monthly average power factor cannot meet the assessment requirement of a power supply company due to the fact that power utilization and power generation scenes possibly exist in a power distribution system at the same time is fundamentally solved; and high-cost hardware investment for blindly adding compensation capacity and improving the compensation precision of the controller in order to meet the assessment requirement of a power supply company on a power factor is effectively avoided.