14 results about "Diode rectifier" patented technology

This invention belongs to the field of high-voltage direct current (HVDC) transmission in power systems, specifically relating to a method, equipment, and medium for AC fault ride-through control at the sending end of a new energy source transmission system via a DRU-HVDC. When an AC fault occurs at the sending end, the grid-side converter of the new energy power station exits the active, reactive, and voltage loops, retains the inner current loop, and switches to maximum current output mode, locking the frequency to the rated value. Simultaneously, the receiving-end converter station exits the DC voltage outer loop, retains the inner current loop, and controls the DC current according to preset commands. During the fault duration, the diode rectifier station remains on and transmits maximum active power. After the fault is cleared, the output current of the new energy power station is reduced to the rated value, and then the power and voltage control loops are restored; the receiving-end converter station resumes constant DC voltage operation. This invention achieves maximum power control through preset commands. By controlling and switching between the new energy power station and the receiving-end converter station, the DRU is effectively maintained on, improving the active power transmission capacity and system recovery speed during faults.

The application provides a DRU-LFAC system and a wind turbine generator network type control and black start control method, and relates to the technical field of wind power generation. The offshore wind farm is a permanent magnet direct drive full power wind turbine generator, low frequency alternating current is sent to the onshore back-to-back converter through a low frequency side subsystem, the onshore back-to-back converter converts the low frequency alternating current into high frequency alternating current and sends the high frequency alternating current into an onshore power grid, the onshore back-to-back converter comprises a twelve-pulse diode rectifier unit and a modular multilevel converter, and a filter is used for reactive power compensation. The DRU-LFAC system has active power-voltage coupling characteristics and reactive power-frequency coupling characteristics. The application solves the problems that the low frequency side power characteristics of the current DRU-LFAC system are different from those of the traditional power system and cannot be effectively analyzed, the current traditional wind turbine generator control strategy is not applicable to the DRU-LFAC system, and the offshore wind farm cannot be started through a conventional process due to the unidirectional conduction characteristics of the DRU.

The application discloses a topology structure and a control method of a bipolar composite offshore converter station, belongs to the technical field of offshore power transmission and distribution, and aims at solving the problems of large volume, complex structure and poor system reliability of the existing offshore wind power. The bipolar composite offshore converter station comprises a positive pole and a negative pole; the positive pole adopts a half-bridge modular multilevel converter topology structure, the negative pole adopts a diode rectifier topology structure, the two topology structures are connected in parallel at an alternating current side and are connected in series at a direct current side, and a direct current connection point is used as a grounding pole to form a symmetric bipolar structure. The topology structure of a shore converter station comprises: the positive pole and the negative pole both adopt a half-bridge modular multilevel converter topology structure. The control method comprises the following steps: when a direct current of the grounding pole increases from zero, an alternating current voltage rated value of the offshore converter station is added with a fine adjustment amount, the added value is used as a given value of a d-axis voltage ring of a wind turbine, the direct current of the grounding pole is kept as zero, power balance control of the positive pole and the negative pole is realized, and the application is used for the offshore converter station.

This invention discloses a hybrid converter valve topology and control method suitable for DC transmission from offshore wind power, belonging to the field of new energy power generation and DC transmission technology. This topology connects a three-phase adjustable reverse voltage cascaded bridge arm in series with a three-phase diode rectifier bridge arm. This invention employs a half-cycle energy balance overmodulation control strategy, enabling the system to operate stably at unity power factor and eliminating voltage ripple on the DC side. The topology is simple in structure, requires no additional filtering stage, and significantly improves power density and semiconductor device utilization while reducing engineering implementation difficulty.

The application discloses a kind of excitation system multi-mode starting control loop and method, the control loop includes: synchronous generator G, electric brake circuit, excitation starting circuit, the electric brake circuit includes electric brake power supply, electric brake transformer ZDB, electric brake alternating current circuit breaker S103, rectifier bridge SCR and direct current magnetic field circuit breaker S101, the electric brake power supply is connected to electric brake alternating current circuit breaker S103 by electric brake transformer ZDB, then to rectifier bridge SCR;The direct current that the rectifier bridge SCR rectifies after output is connected to the rotor of synchronous generator G through direct current magnetic field circuit breaker S101;The excitation starting circuit includes AC excitation power supply, diode rectifier bridge, excitation contactor K1, fuse F01 and F02;The application guarantees the success rate of each mode starting for the first time, and eliminates the hidden trouble brought by temporary change of external loop for test under test mode.

This invention relates to the field of thermoacoustic linear generators, and provides a thermoacoustic engine-driven turbine expansion power generation system. The thermoacoustic engine-driven turbine expansion power generation system includes a thermoacoustic engine unit, an acoustic diode rectifier unit, and a turbine expansion power generation unit. This thermoacoustic engine-driven turbine expansion power generation system combines the advantages of high efficiency and no moving parts in thermoacoustic engines with the mature technology and high power density of turbine expansion power generation, constructing a novel thermoacoustic-electric conversion technology solution. It breaks through the technological path dependence of existing reciprocating linear generators, effectively solving the problem that existing thermoacoustic linear generators cannot meet the demand for high-power generation, reducing technical difficulty and manufacturing costs, and has a wide range of applications, with good environmental benefits and economic value.

This invention discloses a method and system for suppressing harmonic currents in a cascaded submodule-connected diode bridge controllable rectifier, relating to the field of harmonic suppression technology for power electronic converters. The controllable rectifier comprises cascaded submodule units, a transformer, and a diode rectifier unit. This invention obtains the amplitude and phase angle of harmonic current components in the AC line through Fourier decomposition. The amplitude of the harmonic current components is used for negative feedback PI control to generate a compensated harmonic voltage amplitude. The phase angle of the harmonic current components is increased by 90 degrees to obtain the compensated harmonic voltage phase angle. The compensated harmonic voltage component is subtracted from the modulation wave of the cascaded submodules to generate a corresponding harmonic current component that cancels out the original harmonic current components in the AC line. This invention achieves harmonic current filtering without requiring additional filtering equipment for the diode rectifier unit, has a simple control strategy, and effectively filters out harmonic current components in the AC line.

This application provides a boost converter topology, relating to the field of boost converter technology. The boost converter topology includes: an input module, a switching transistor module, a flying capacitor clamping module, a diode rectifier module, an output module, a pre-charge module, and a controller module. The switching transistor module includes at least three switching transistors connected in series. The diode rectifier module includes at least three power diodes connected in series. The flying capacitor clamping module includes multiple flying capacitors. The number of flying capacitors, the number of power diodes, and the number of switching transistors are related to each other. The flying capacitor clamping module is used to limit the voltage stress on each switching transistor in the switching transistor module to one-Nth of the output voltage; where N is the number of switching transistors. The boost converter topology of this application reduces the voltage stress on the switching transistors, improving the reliability and safety of the boost converter.

The utility model discloses a kind of photovoltaic direct-drive control system of pumping unit based on ac-dc dual power supply, including photovoltaic array, ac-dc dual power supply input inverter, energy consumption braking unit, power frequency bypass switch and control module.Inverter adopts three-level NPC topology, and energy two-way block is realized by diode rectifier bridge and IGBT parallel connection.Initial power-on when direct current side priority power supply, seamless switching to ac power grid when power is insufficient.Energy consumption braking unit triggers when direct current bus voltage reaches 760V, cooperates IGBT chopper control and inhibits reverse power generation.Control module injects reverse excitation current by reverse load algorithm and inhibits reverse power generation, based on motor current harmonic inversion load change, dynamically adjusts inverter output frequency and duty cycle, the utility model can solve the problems, such as periodic reverse power generation, dynamic load fluctuation, system balance degree regulation difficulty in prior art, improve the utilization of photovoltaic energy, reduce system cost, improve the stability and reliability of system.

The application discloses a flying capacitor voltage equalization interconnection circuit, comprising a conversion module and an equalization module, the conversion module is a two-phase or more than two-phase N-level flying capacitor conversion circuit, and the N-level flying capacitor conversion circuit comprises a plurality of conversion bridge arms, each conversion bridge arm comprises N-2 flying capacitors, the equalization module comprises a plurality of diode rectifier bridge arms, and the plurality of diode rectifier bridge arms are connected in parallel to both ends of each flying capacitor; the diode rectifier bridge arm is composed of two diodes connected in series; the diode rectifier bridge arms connected in parallel to each flying capacitor of each conversion bridge arm and the diode rectifier bridge arms connected in parallel to one flying capacitor of the next switching bridge arm form an interconnection group, the midpoints of the two diode rectifier bridge arms in the interconnection group are connected to each other through wires, and the sum of the levels of the flying capacitors corresponding to the two diode rectifier bridge arms is N-1; when N is an odd number, the midpoints of the diode rectifier bridge arms connected in parallel to the middle-level flying capacitors of all the conversion bridge arms are connected together.

The application discloses a power module and a modular power supply, comprising a multi-winding high-frequency transformer, a power frequency rectifier, a high-frequency converter, a diode rectifier bridge, an LC branch, a direct-current interface circuit and an equalization interface circuit; according to the port composition type, the application is divided into the following three parts: the first part is connected with the primary side high-frequency converter through the LC branch, the primary side high-frequency converter is connected with the power frequency rectifier, and the power frequency rectifier output constitutes an alternating current port; the second part is connected with the secondary side rectifier bridge through the LC branch, the secondary side rectifier bridge is connected with the direct-current interface circuit, and the direct-current interface circuit output constitutes a total direct-current port; the third part is connected with the equalization interface circuit through the LC branch, and an equalization port is constituted. The application greatly reduces the volume and weight of the magnetic element, improves the power density of the equipment, introduces the resonance technology to reduce the switching loss and improve the system efficiency, and is matched with independent AC accessories to construct a three-phase four-wire alternating current port, and provides multiple types and multiple functions of electrical interfaces.

This invention discloses a topology construction and operation control method for an aerial wind power generation system. The method includes: First, constructing a core electrical structure, the aerial portion of which consists of multiple generator-passive diode rectifier units connected in series, directly generating medium-voltage DC transmission without an onboard boost converter, achieving extreme lightweighting of the aerial platform structurally; Second, adopting a ground parameter adjustment method adapted to this lightweight topology, adjusting the DC voltage of the ground-connected grid converter to match the output characteristics of the aerial passive series circuit, ensuring stable system power output; Finally, through topology steady-state characteristic adaptation analysis, clarifying the system operating parameters and adjustable power boundaries, providing adaptation support for safe topology operation. This invention, starting from topology design, solves the "weight-voltage" paradox faced by existing high-altitude wind energy systems in large-scale applications, while avoiding the problems of insufficient operational stability and low reliability caused by complex topology adaptation.

The application discloses a high-voltage and low-voltage direct-current dual-output three-stage generator system and a design method. The system comprises a three-stage generator and a controller. The three-stage generator is composed of a permanent magnet auxiliary exciter, a main exciter, a main motor, a rotary transformer and a rotary rectifier. The controller comprises a voltage regulating circuit, a thyristor rectifier bridge, a diode rectifier bridge, a control circuit, a power generation control relay and a current sensor. The main motor is provided with a low-voltage three-phase winding and a high-voltage three-phase winding, which meet the requirements of low-voltage direct current and high-voltage direct current respectively. The application adjusts the excitation current of the excitation winding of the main exciter through the voltage regulating circuit, so as to realize the stable voltage of the low-voltage direct current at the expected voltage value. The output high-voltage direct current is stabilized at the expected voltage value by means of phase control rectification control. Meanwhile, the thyristor rectifier bridge generates power and stabilizes voltage by adopting the same switching frequency as the output frequency of the generator, and has the characteristics of low loss, low high-frequency ripple spectrum component, weak high-frequency conduction and radiation interference and high power density.

This invention relates to the field of offshore wind power DC transmission technology, and discloses a grid-connected wind power diode rectifier DC transmission system and its control method. The system includes a diode rectifier module, a black-start converter module, a bus voltage support module, and an onshore converter station. The black-start converter module dynamically adjusts the system's active power during the system startup phase after establishing the AC voltage of the offshore combiner bus based on an external AC power source. The bus voltage support module dynamically adjusts the system's reactive power after the offshore combiner bus voltage is established, maintaining the stability of the offshore combiner bus's AC voltage. This invention enables black-start and continuous energized operation of the offshore wind power diode rectifier transmission system without relying on grid-connected wind turbines, significantly improving the system's reliability and availability.