3614 results about "Dc voltage" patented technology

The invention discloses a fault ride-through test method for an offshore wind power flexible direct output system, and the method comprises the steps: building a fault equivalent circuit of the offshore wind power flexible direct output system, analyzing the operation characteristics of an AC power grid side under a low-voltage fault, and determining the incidence relation between the DC side excess energy and the power grid voltage drop; establishing a model representing each component in the fault equivalent circuit, wherein the components at least comprise a machine-side converter, a grid-side converter, a direct-current capacitor and an unloading resistor; when a low-voltage fault of an alternating-current power grid side is detected, executing the following cooperative control based on the model: synchronously starting unloading resistance control and reactive power support control, wherein an unloading resistor dissipates excess energy of a direct-current side through a direct-current chopper; the grid-side converter injects a capacitive reactive current which is deeply matched with the voltage drop of the power grid so as to improve the voltage of a grid-connected point; and if the direct-current voltage continuously exceeds the preset threshold value, starting power prompt drop control, and reducing the output power of the unit according to a gradient until the system recovers to be stable.

The invention provides an array substrate and a display device, and the array substrate comprises a substrate; the gate insulating layer is arranged on the substrate; the data line is arranged on the gate insulating layer; the first passivation layer is arranged on the gate insulation layer and covers the data line; the first shielding electrode is arranged on the first passivation layer, and the first shielding electrode is connected with the direct-current voltage signal output end; the second passivation layer is arranged on the first passivation layer and covers the first shielding electrode; the common electrode is arranged on the second passivation layer, and a part of the common electrode is overlapped with the data line and the first shielding electrode; the pixel electrode and the common electrode are arranged on the same layer or stacked, and the pixel electrode is insulated from the common electrode. The first shielding electrode is connected to the direct-current voltage signal, so that the data voltage signal on the data line does not affect the signal on the common electrode, coupling capacitance between the common electrode and the data line is avoided, and poor display of picture flicker is avoided.

A converter system, e.g., for vehicle-to-vehicle charging, includes galvanically-isolated modular first and second converters having the same maximum voltage rating, a direct current (DC) voltage bus interconnecting the converters, and an electronic controller. An input voltage to the DC bus is converted into an output voltage via switching control signals to the modular converters. The system's voltage rating may equal the maximum of the input and / or output voltage, or it may equal the maximum input voltage and be about 50-percent of the maximum output voltage. The maximum input and output voltages may be equal. When the voltage rating is about 50-percent of the maximum input voltage, capacitors may be connected in parallel with the modular converters on an input side thereof. Switching circuits may be connected to the bus to control the conversion of the input voltage via switching control signals.

The present invention provides a topology, method and system for bi-directional power conversion of excitation power supply for power battery testing, wherein the topology comprises a three-phase PWM (pulse width modulation) converter, a high-frequency isolation three-level LLC (logical link control) resonant converter and a DC-DC (direct current) converter forming a topology structure for a three-stage power conversion; an input end of the three-phase PWM converter is connected to a power grid side; the high-frequency isolation three-level LLC resonant converter is connected between the three-phase PWM converter and the DC-DC converter in series and is configured for realizing bi-directional DC voltage conversion and isolation, and to raise a busbar voltage between the high-frequency isolation three-level LLC resonant converter and the DC-DC converter; and, the DC-DC converter is configured to generate charging and discharging excitation currents for a power battery testing.

The invention discloses a fault processing method for an offshore wind power direct current parallel sending-out system through a DRU-MMC. The fault processing method comprises the steps that direct current energy consumption devices are arranged at direct current outlets of respective land MMC converter stations of a DRU-HVDC system and an MMC-HVDC system; when the alternating current power grid at the receiving end has an alternating current fault, the direct current energy consumption device is controlled to adopt a direct current voltage suppression strategy; when the DRU-HVDC system and the MMC-HVDC system respectively have direct current faults, different locking and circuit breaker disconnection time sequence control strategies are adopted, and in the direct current fault ride-through period, a direct current suppression strategy and a direct current voltage suppression strategy are controlled to be adopted by a direct current energy consumption device of the DRU-HVDC system. Therefore, the fault ride-through capability of the DRU-MMC direct current parallel sending-out system of the offshore wind power can be effectively improved, and stable operation of the system is ensured.

The invention discloses a control device and a control method of a radio frequency power supply and the radio frequency power supply. The control device comprises an adjusting module, a control module and a sampling module. The adjusting module is used for outputting a driving signal to a radio frequency input end of the power amplification module according to a reference radio frequency signal output by the signal generation module and a second bias voltage value output by the control module; the sampling module is used for collecting actual forward power output to the load by the power amplification module and actual reverse power reflected by the load; the control module is used for applying a direct-current voltage value smaller than the maximum input voltage value to the power supply end of the power amplification module according to the actual reverse power and the reverse power threshold value when the actual reverse power is larger than the reverse power threshold value, and adjusting a second bias voltage value according to the actual forward power and the forward power threshold value. When the load impedance changes, the radio frequency power supply can be effectively protected from being damaged by overlarge reverse power, continuous output of forward power can be maintained, and process interruption is avoided.

The invention discloses a weight coefficient-free model prediction control system and method for a permanent magnet synchronous motor, and particularly belongs to the field of permanent magnet synchronous motor control. The control system comprises a direct current voltage source, a three-phase converter, a permanent magnet synchronous motor, a rotating speed outer ring PI control module, an MTPA flux linkage calculation module and a model prediction control module. The control method comprises the following implementation steps: firstly, establishing a torque and flux linkage prediction model of the permanent magnet synchronous motor; then, a reference torque amplitude value and a reference flux linkage amplitude value are obtained through a rotating speed outer ring PI controller and a maximum torque per ampere (MTPA) calculation module respectively; secondly, constructing an independent torque cost function and a flux linkage cost function according to the torque error and the flux linkage error, and forming a cascade form; evaluating the switching states by using a cost function, selecting two vectors from the eight switching states of the converter by using the independent cost function of the torque (or flux linkage), and selecting an optimal vector from the two vectors by using the independent cost function of the flux linkage (or torque); and finally, the execution sequence of the torque and flux linkage cost function is alternated in each subsequent period. Compared with the prior art, the method avoids complex weight coefficient design through a cost function cascading mode, alternates the execution sequence of the cost functions in each period, dynamically balances the weights of the two control targets, and reduces the number of calculation times.

The invention relates to the technical field of power system control, in particular to a direct-current capacitor self-synchronizing grid-connected control strategy method, system, equipment and medium, a direct-current capacitor energy dynamic model is established based on an actual energy balance relation, a direct-current voltage signal is acquired in real time, and a synchronous compensation signal is calculated based on the acquired direct-current voltage signal; performing phase compensation and gain adjustment on the synchronous compensation signal through a correction link based on the calculated synchronous compensation signal, adjusting the internal frequency of the inverter based on the synchronous compensation signal after phase compensation and gain adjustment, controlling the DC voltage through the internal frequency of the inverter, and establishing a self-synchronization control model; and based on the self-synchronization control model, establishing an adaptive control algorithm, generating a damping coefficient and a virtual inertia coefficient through the adaptive control algorithm, and dynamically adjusting control parameters according to the damping coefficient and the virtual inertia coefficient.

The invention relates to the technical field of battery modeling and photovoltaic energy storage systems, and discloses a self-adaptive battery modeling method for direct current bus voltage support of an optical storage system. The method comprises the following steps: establishing a basic model comprising a direct-current voltage source, an ohmic internal resistor and an RC polarization network; the voltage drop depth is obtained by monitoring the voltage of the direct-current bus in real time and used for correcting the polarization resistance; and performing differential operation on the voltage to obtain a change rate so as to adjust the polarization capacitance. And dynamically optimizing the battery model by combining correction results of the two, and realizing adaptive updating of model parameters. And applying the optimization model to the optical storage integrated grid-connected system. The adaptability of the battery model to the dynamic working condition is improved.

The invention belongs to the field of new energy, and particularly discloses a direct-current bus voltage control method and system of a flywheel energy storage system. Comprising the following steps: if DC bus voltage is in a normal range, DC voltage forms a q-axis current reference signal after being adjusted by a PI controller, the q-axis current reference signal generates a q-axis voltage instruction signal after being adjusted by a current control loop PI, and a dq-axis voltage instruction value is generated through decoupling; if the current control loop slightly deviates from the normal range, parameters of a PI controller are adjusted, so that an integration link plays a leading role in control output, a virtual impedance link connected to the current control loop in parallel is adjusted, and a dq-axis voltage instruction value is generated; and if the voltage is seriously deviated from the normal range, a grid-side power signal is fed forward to a machine-side direct-current voltage control loop, virtual resistance in a virtual impedance link is adjusted, and a dq-axis voltage instruction value is generated. According to the invention, the control mode is automatically switched according to different conditions of the DC bus voltage by adopting a threshold-grading regulation and control strategy, and the adaptability to large disturbance is improved while the steady-state precision of the system is maintained.

The invention discloses a hybrid direct current transmission power coordination control device and a control method and equipment thereof, and relates to the technical field of offshore power generation, and the hybrid direct current transmission power coordination control device comprises a diode rectifier unit and a first modular multilevel converter which are connected with an offshore wind plant, the sending-end converter station is used for converting alternating current generated by an offshore wind plant into direct current and outputting the direct current; the second modularized multi-level current converter is connected with the diode rectifier unit and the land power grid and is used for restoring the direct current into the alternating current and transmitting the alternating current to the land power grid; and the control module is connected with the first modular multilevel converter and is used for controlling the DC voltage of the first modular multilevel converter based on the fluctuation power according to the transfer relation between the active power and the DC voltage of the sending end converter station, so that the higher requirement of the rated capacity of the MMC in the related technology is met, and the reliability of the MMC is improved. And the engineering construction cost is increased.

The invention relates to the technical field of automatic welding, and discloses a micro welding seam tracking method and system based on electromagnetic induction. According to the method, a high-frequency alternating magnetic field is applied to a welding seam area through an exciting coil in the micro electromagnetic sensing core; an induction coil in the electromagnetic sensing core is used for detecting magnetic field disturbance caused by geometric shape changes of the weld groove, and induction signals are obtained; processing the induction signal through a signal processing circuit integrated in the probe, namely converting the impedance change of the coil into a voltage signal, demodulating and filtering the voltage signal, and extracting a direct-current voltage signal corresponding to the deviation of the probe relative to the central position of the welding seam; the direct-current voltage signals serve as position feedback information to be output to a welding robot control system; and the movement track of the welding robot is adjusted in real time according to the position feedback information, and welding seam tracking and path deviation correction are achieved.

The invention discloses a global cooperative control method and system for unbalanced fault ride-through of a multi-terminal DC power grid, and the method comprises the steps: constructing a fault detection model based on the positive sequence voltage drop depth and the negative sequence voltage size of the AC side of each converter station, automatically judging an unbalanced fault, and carrying out the fault detection when the fault is detected. Calculating the maximum allowable active current based on a fault station unbalanced current control model to carry out current limiting control on the converter station; and carrying out output power adjustment on the DC voltage deviation of the non-fault station based on the non-fault station power cooperation model. Asymmetric fault ride-through is carried out by using a constrained and optimized current instruction generation algorithm, and the capacity of a converter is dynamically and accurately distributed and utilized in a limited manner, so that the voltage support capability of a fault alternating-current power grid is maximized, and globally optimized adaptive power distribution is realized; the power of the non-fault station is calculated and distributed in a centralized manner and is dynamically adjusted according to the real-time available capacity, so that the self-adaption and global optimization of the running state change of the power grid are realized, and the fault handling toughness and reliability of the power grid are improved.

An inertia cooperative control method of an integrated optical storage alternating current and direct current hybrid micro-grid comprises the steps that firstly, according to static and dynamic power capacities of energy storage units in direct current sub-grids and allowed direct current voltage deviation, sub-grid equivalent virtual resistance and virtual capacitance are calculated; secondly, RC + R type parallel virtual impedance parameters are distributed according to the power proportion of each energy storage unit, and multi-energy-storage cooperative response power disturbance according to the capacity is achieved; then, a phase angle is generated based on the mapping relation between direct-current side voltage and frequency, an alternating-current voltage amplitude instruction is determined in combination with reactive power droop control and feeder impedance voltage drop compensation, and a dq-axis voltage instruction is generated through virtual impedance compensation; normalized three-phase modulation waves are obtained through voltage-current double closed-loop control and dq / abc coordinate transformation, and six paths of PWM signals are generated to drive an interconnection converter after the normalized three-phase modulation waves are compared with triangular carrier waves. The method does not need to depend on external communication, has the capabilities of autonomous inertia support, voltage and frequency coordinated regulation and reasonable multi-source power distribution, and improves the stability and dynamic response performance of the system under island operation.

The utility model relates to a rear-phase-cut single-live-wire type wall light modulator, which comprises an MOS (Metal Oxide Semiconductor) tube switch loop unit, a singlechip control unit and a direct-current power supply unit, the MOS tube switch loop unit comprises a wiring terminal J2 connected with an MOS tube Q1, a grid electrode of the MOS tube Q1 is connected with four resistors in series in sequence and then is connected with an MOS tube Q2, a drain electrode of the MOS tube Q2 is connected with a diode D2, the diode D2 is connected with a diode D1, a fixed end contact of a single-pole double-throw switch is connected with the MOS tube Q2, and two movable end contacts of the single-pole double-throw switch are connected with the wiring terminal J1 and the wiring terminal J3 respectively; the direct-current power supply unit comprises an alternating-current voltage waveform acquisition circuit, a direct-current voltage drop circuit, an overcurrent protection circuit and a filtering voltage stabilizing circuit; according to the single-chip microcomputer control unit, a linear sliding potentiometer is connected with the PC2 end of a single-chip microcomputer after being connected with a resistor in series, the linear sliding potentiometer and a rotary potentiometer are sequentially connected between the output end of the direct-current power supply unit and the ground in series, a triode Q6 is connected with a triode Q5 and then connected with the collector electrode of a triode Q7, and the base electrode of the triode Q7 is connected with the PA6 end of the single-chip microcomputer after being connected with a resistor in series.

The invention provides a high-low voltage valve group heterogeneous flexible direct current power transmission system and a direct current fault clearing method, and belongs to the field of power transmission and distribution of electric power systems, and the system comprises an alternating current collection network which is used for collecting alternating current electric energy of a new energy base; each of the sending end converter station and the receiving end converter station comprises a negative-voltage type modular multilevel converter and a half-bridge type modular multilevel converter; the direct-current overhead line is electrically connected between the sending-end converter station and the receiving-end converter station, and direct-current quick switches are arranged on the two sides of the direct-current overhead line respectively; the sending end converter station adopts cooperative network construction control and is used for maintaining the voltage stability of the alternating current collection network; and the receiving end converter station adopts direct-current voltage control and is used for maintaining the voltage stability of the direct-current electric energy of the direct-current overhead line. According to the invention, large-scale long-distance new energy supply is realized, and the construction cost and the operation loss are reduced.

The invention relates to an MMC-CLCC novel DC power transmission system coordination control method, and belongs to the technical field of hybrid DC power transmission. The method comprises the following steps: establishing an MMC-CLCC hybrid DC power transmission system topology architecture, determining an optimal proportion of full-bridge and half-bridge sub-modules according to requirements of system DC voltage and the like, and determining a control strategy during steady-state operation; analyzing the dynamic process of the system under the alternating current fault of the receiving end, and clarifying the power operation characteristics of the CLCC; designing a calculation process of direct current, active power and reactive power operation limits of the inverter station under multi-condition constraints, and constructing a safe operation domain of the inverter station; and proposing a CLCC turn-off angle adjustment strategy based on reactive sensitivity constraint and an MMC coordination strategy based on maximum power transmission. The method can provide support for the receiving-end AC system during the fault period of the receiving-end power grid, guarantees the DC power transmission capability to the greatest extent, and is suitable for a large-scale new energy cross-regional power transmission scene.

A voltage conversion system includes user interface circuitry disposed on the voltage conversion system. The user interface circuitry is configured to input at least one electrical parameter based on user input. At least one parameter of the at least one electrical parameter comprises a plurality of adjustable values and corresponds to a conductor resistance of electrical conductors coupled to the voltage conversion system. Each adjustable value of the at least one parameter corresponds to a range of two or more values. The voltage conversion system includes conversion circuitry configured to generate an adjusted direct current (DC) voltage from an input DC voltage based on the at least one electrical parameter.

Systems and methods are provided for a transportation vehicle. A system includes a power delivery component comprising a power delivery port and a power meter component to measure a power delivery component voltage received at the power delivery component via a cable, and a seat box connected to the power delivery component via the cable and configured to provide a supply voltage to the power delivery component via the cable. The seat box comprises a DC-to-DC converter to convert an initial DC voltage to a seat box DC voltage, a voltage compensation component to change the seat box DC voltage to the supply voltage, and a microcontroller configured to receive the power delivery component voltage from the power meter component, determine a voltage drop across the cable based on the power delivery component voltage, and control the voltage compensation component to adjust the supply voltage based on the voltage drop.

The invention discloses a composite voltage generation device and a cable insulation performance evaluation system and method, and relates to the technical field of high-voltage insulation testing. The composite voltage generating device comprises a synchronous controller, a direct current source, an impact source, an IGBT active protection unit and a magnetic isolation coupler, and by means of the excellent characteristics of the IGBT and the magnetic isolation coupler, the superposition time sequence accuracy of direct current and impact voltage is improved, and waveform distortion is reduced. The IGBT active protection unit comprises a first IGBT and a second IGBT, and direct-current voltage polarity switching can be realized through selective conduction of the IGBTs; the RC circuit is connected in parallel between the collector electrode of the first IGBT and the emitter electrode of the second IGBT, reverse current flowing back to the direct current source direction can be discharged through the RC circuit, the risk of energy flowing back is reduced, meanwhile, the magnetic isolation coupler can completely block direct current, and an impact source is protected against the influence of direct current voltage; according to the invention, the authenticity and reliability of cable insulation performance evaluation can be effectively improved.

The invention discloses a power supply control system and method for an eVTOL low-voltage distribution box, and relates to the technical field of power supply control, and the system comprises a multi-source double-bus power supply unit, a voltage reduction unit and an output unit. The multi-source double-bus power supply unit comprises a first bus independent power supply channel and a second bus independent power supply channel, the first bus independent power supply channel and the second bus independent power supply channel are isolated based on a contactor, the first bus independent power supply channel comprises x heterogeneous power sources and x ideal diodes, and the x heterogeneous power sources comprise a high-voltage-to-low-voltage DC-DC power source, a ground power source and n lithium battery power sources. The second bus independent power supply channel comprises y paths of heterogeneous power supplies and y ideal diodes, and the y paths of heterogeneous power supplies comprise y paths of lithium battery power supplies; the step-down unit comprises m paths of DC-DC step-down converters; and the output unit comprises m ideal diodes which are connected in parallel with the output end of the DC-DC buck converter. According to the invention, the stability and quality of power supply are ensured, and airborne equipment is ensured to work in a stable voltage and current environment.

The invention discloses a method for measuring and analyzing residual magnetism characteristics of an iron core. According to the method, a to-be-detected iron core is demagnetized, preset residual magnetism is set, direct-current voltage excitation with opposite polarities, the same amplitude and the same duration is applied to a primary winding of the to-be-detected iron core, and transient current response signals are synchronously collected; two groups of current under positive / negative polarity excitation are extracted, and the residual magnetism direction is judged by comparing the change rate of the current; a curve of equivalent resistance changing along with time is calculated based on forward current and voltage, a resistance value corresponding to a characteristic inflection point moment is selected, the resistance value is substituted into a pre-established residual magnetism-equivalent resistance empirical formula to deduce the magnitude of residual magnetism, and a matched iron core residual magnetism detection and demagnetization integrated system integrates information management, residual magnetism detection, demagnetization and display modules. And closed-loop automation of detection, analysis and demagnetization is realized. According to the method, a magnetic field sensor is not needed, the residual magnetism direction and size can be synchronously obtained in a high-precision and robust mode only through port electric signals, and the method is suitable for on-site off-line or live detection.

The invention, which belongs to the technical field of the energy storage converter, discloses an electrical parameter sensing-based service life monitoring system for a capacitor of a network-forming type energy storage converter, comprising the following steps of: synchronously acquiring a direct-current voltage signal and a three-phase alternating-current signal of a direct-current bus capacitor through an electrical parameter acquisition module to form a multi-dimensional feature vector; a state observer built in the ESR estimation module is used for analyzing the signal, a target capacitor ESR value is obtained, and a capacitor core temperature value is obtained through back-stepping through an electric-thermal coupling field analysis model of a core temperature back-stepping module in combination with preset capacitor surface temperature data; based on the ESR value and the capacitor core temperature value, a life prediction module calculates the residual life and health degree index of the capacitor; and the power scheduling module executes capacitor health degree-power output joint scheduling according to the health degree index, adjusts the power fluctuation range of the converter, and feeds back real-time working condition data to the electrical parameter acquisition module, thereby realizing accurate monitoring of the capacitor state and intelligent scheduling of the converter power.

The invention discloses a dynamic power management method for an all-electric ship hybrid energy storage system. The method comprises the following steps: S1, establishing a direct-current voltage dynamic model and a ship hybrid energy storage system model based on a ship micro-grid structure of a ship; s2, establishing a multi-working-condition propulsion power model based on the movement mechanism of the ship; s3, establishing a joint SOC-SOP estimation model based on the nonlinear relationship among the state of charge, the battery power characteristics and the ambient temperature; s4, on the basis of the direct-current voltage dynamic model, the ship hybrid energy storage system model and the multi-working-condition propulsion power model, establishing a dynamic power distribution model; and S5, estimating an available power range of the battery through a combined SOC-SOP estimation model, inputting the available power range into the dynamic power distribution model, obtaining a dynamic power distribution strategy, and realizing dynamic power distribution of the ship hybrid energy storage system. According to the method, the dynamic power management of the hybrid energy storage system of the all-electric ship under the uncertain navigation condition is optimized, and the stability and the economical efficiency of a ship power system are improved.

The invention specifically discloses an energy storage converter signal high-precision fault diagnosis method and system, and the method comprises the steps: firstly carrying out the synchronous processing of three-phase current and DC voltage of an energy storage converter, and constructing a combined signal view which can reflect the instantaneous dynamic state of a system; on the basis, an adaptive signal decomposition technology is introduced, and an original signal which is highly coupled and full of noise is deeply deconstructed into a series of intrinsic mode components with more physical significance. And through a global context coding mechanism, internal relevance and co-evolution laws of the modal components on a time sequence are captured and quantified, so that a depth representation vector capable of amplifying fault weak feature differences is constructed. And finally, based on the depth representation, driving an intelligent classifier to realize accurate identification and positioning of different IGBT open-circuit faults. Therefore, weak differences between different fault modes can be effectively amplified, and reliable technical guarantee is provided for safe operation of the energy storage converter.

The invention belongs to the technical field of resonance stability of a power system, and discloses a high-voltage reactance configuration method for improving resonance stability of the power system, which solves the precision defect caused by neglecting voltage fluctuation in traditional modeling by establishing a fan and static var generator precise admittance model considering DC voltage fluctuation. The dq admittance model of the alternating current system is obtained according to the nodes, connected to the alternating current system, of the fan and the static var generator, general calculation of dq admittance of the multi-node alternating current system is achieved, the limitation that only single-node modeling is supported in a traditional method is broken through, the complex stability problem is quantized into an optimizable amplitude margin index, and the stability of the system is improved. A clear basis is provided for resonance stability analysis, high reactance configuration is expanded from traditional reactive compensation to resonance stability active optimization, and the resonance stability design efficiency of the new energy grid-connected system is remarkably improved.

The embodiment of the invention provides a flywheel energy storage system and an electrical control method and system thereof, and the electrical control method comprises the steps: collecting the operation state data of the flywheel energy storage system in real time, and carrying out the preprocessing of the operation state data; inputting the preprocessed operation state data into a parameter adaptive control algorithm, dynamically adjusting control parameters of the algorithm through fuzzy logic, and generating a control instruction for controlling the power converter; based on the control instruction and the real-time demand of a power grid, cooperatively controlling the output power and the direct-current voltage of the flywheel energy storage system, and when it is detected that the direct-current voltage deviates from a target range, automatically switching an electrical control mode to a voltage stabilization mode for stabilizing the direct-current voltage within the target range; and monitoring the operation state of the flywheel energy storage system in real time, and triggering a protection mechanism when at least one abnormity of overvoltage abnormity, overcurrent abnormity or mechanical fault abnormity is detected.

The invention discloses a flexible interconnection and mode smooth switching method for a distributed power generation system, and relates to the technical field of distributed power generation, and the method comprises the steps: building a droop control relation through continuously collecting DC voltage and current for a source side rectifier of each power generation unit; in a normal mode, the output current of the back-to-back rectifier and the voltage of an intermediate capacitor are collected, the same phase of the current and the load current is kept by using phase locking control, and voltage regulation is realized by combining a dq coordinate model; when a fault of a source side rectifier is detected, an alternating current reference value is generated based on intermediate capacitor voltage deviation and is input into a single current loop controller for voltage stabilization, and meanwhile, a phase advance, adaptive gain and integral saturation resistance mechanism is introduced, so that quick response and stable operation are ensured; in the mode switching process, normal control quantity and fault control quantity are subjected to weighted fusion, and dynamic consistency is achieved through pole matching and reference pre-alignment; the intermediate capacitor voltage fluctuation is significantly reduced, the recovery time is shortened, and the system stability and reliability are improved.

A control method for suppressing an overvoltage of the receiving end hybrid modular multilevel converter with full-bridge submodules and half-bridge submodules (F / HMMC) under the fault at the receiving-end alternating-current (AC) system of the hybrid high-voltage direct-current (HVDC) transmission system. After a short-circuit fault occurs in a receiving-end AC) system of the hybrid HVDC transmission system, an AC voltage drop is generated, and the effective voltage of the receiving-end AC bus at the current time is measured. Because the hybrid modular multilevel converter (MMC) is capable of actively decreasing the DC voltage for operation, on a premise of ensuring that its output current is always within a rated current range, a control manner of setting the reference DC voltage and making the reference DC voltage not greater than the effective voltage of the AC bus enables receiving end power to be sent out, thereby suppressing an overvoltage of the receiving-end F / HMMC.

The invention discloses a multi-parameter high-precision automatic test method and system for a voltage reference source, and the method comprises the following steps: selecting a test scheme according to the characteristics of a tested voltage reference source device, and carrying out the testing of starting time, initial precision, temperature coefficient, linear regulation rate and long-term stability; the automatic test system controls the adjustable DC voltage source to adjust the input voltage of the tested voltage reference source device according to the selected test scheme, and controls the high and low temperature test box to adjust the working environment temperature of the tested voltage reference source device; the automatic test system reads voltage data collected by the eight-bit and half-digit meter, and analyzes, processes, classifies and stores the voltage data according to a test scheme. The method is used for overcoming the defects of insufficient precision, poor synchronism and tedious process in the traditional test, and provides a reliable technical means for research, development, verification and mass production screening of the high-precision voltage reference source device.