487results about "Conversion with intermediate conversion to dc" patented technology

The invention discloses an impedance self-adaptive control method for a combined type grid-following type and grid-constructing type converter, and relates to the technical field of wind turbine generators. Comprising the steps that S100, two wind driven generators are adopted to construct a combined inverter self-adaptive topological structure; s200, each wind generator is correspondingly connected with a grid-following type inverter and a grid-constructing type inverter through a corresponding rectifier, and the grid-following type inverter and the grid-constructing type inverter are connected with the power grid in parallel in a parallel mode; s300, collecting and processing sample data of the network-following type inverter and the network-constructing type inverter, wherein the sample data comprises machine side control signal parameters and network side control signal parameters; s400, constructing a self-adaptive control model; s500, acquiring a network tracking type error adjustment value by using the network tracking type nonlinear prediction model, and acquiring a network constructing type error adjustment value by using the network constructing type prediction model; and S600, each MPC control module controls the corresponding inverter according to the obtained error adjustment value, the machine side control signal parameter and the network side control signal parameter. Changes of frequency and damping of the power grid are tracked in a self-adaptive mode, positive and negative values of output damping are flexibly adjusted, and the problems of low inertia, negative damping and weak voltage caused by double high can be fundamentally solved.

The invention relates to the technical field of frequency converter harmonic control, in particular to a harmonic control method, system and device applied to a frequency converter, and the method comprises the steps: obtaining the current data of a rectification input side and an inversion output side of the frequency converter; obtaining the difference coefficient of the overall pulsation amplitude change of each period and the irregular coefficient of the corresponding pulsation time change, and further obtaining the harmonic influence coefficient of the rectification input side current of each period with the pulsation amplitude difference and irregular characteristics; calculating a deviation coefficient and a jitter abnormal coefficient of the inversion output side current of each period so as to obtain a harmonic influence coefficient of the inversion output side current of each period having waveform deviation and rapid jitter; therefore, the harmonic delay superposition interference coefficient is obtained, and the output current of the inverter is corrected in combination with the current data of the inverter output side. The harmonic control precision of the frequency converter can be improved.

A power supply system (5) for a plurality of electrolyzers (2, 3, 4) is proposed. The power supply system (5) comprises: - main input terminals (6) intended to be connected to a grid (G), - an AC / AC power converter (7), - a control circuit (10), - a plurality of supply branches (12, 13, 14), - each supply branch (12, 13, 14) comprising a branch transformer (21, 22, 23) including a primary circuit connected to input terminals (15, 16, 17) of the said supply branch and at least one secondary circuit, and at least one rectifier (24, 25, 26) connected to the secondary circuit of the branch transformer, the rectifier comprising output terminals (30, 31, 32) connected to a set of output terminals (18, 19, 20) of the said supply branch to supply the output terminals of the said supply branch with a DC current.

A variable frequency drive with natural heat dissipation, comprising a housing and a front cover, wherein a mounting pad is fixedly mounted in the housing, and a varistor, a rectifier module, a filter, and an inverter module are mounted in sequence on the mounting pad; an air intake cavity is provided in the mounting pad; exhaust holes are provided between the air intake cavity and the top of the mounting pad; air inducing cavities are provided inside both sides of the housing; a through groove is provided between the air intake cavity and each air inducing cavity; and an air inlet is provided between each air inducing cavity and the outer wall of the housing. Natural heat dissipation is achieved within the variable frequency drive through multiple aspects, such as optimizing the design of an air duct, enhancing the heat conduction effect and heat conduction efficiency, and improving the internal environment. By means of a local heat-absorbing assembly, when localized overheating occurs within the variable frequency drive, heat generated by an automatic local component can be rapidly absorbed, thereby providing effective protection for the internal structure.

The invention discloses a power supply system, and relates to the technical field of electrical connection devices, and the power supply system comprises a power supply input end which is used for accessing commercial power; the power supply output end is used for accessing a load; the rectifying circuit and the inverter circuit are sequentially connected in series between the power input end and the power output end; the first switching circuit is connected in series between the power supply input end and the input end of the rectifying circuit; the input end of the energy storage circuit is connected with the output end of the first switching circuit, and the output end of the energy storage circuit is connected with the input end of the inverter circuit; the control unit is respectively connected with the controlled end of the first switching circuit and the controlled end of the energy storage circuit; the invention aims to reduce the economic burden of electricity utilization of the user.

A power management system for an elevator system. A power management system for an elevator system includes a power converter having three input terminals, two of the three input terminals coupled to a main power source for supplying single-phase AC power to the power management system, the power converter configured to convert the AC power from the main power source into DC power on a common DC bus, a secondary power source for supplying DC power to the common DC bus, a power inverter configured to invert the DC power on the common DC bus into AC output power for driving an electric motor of the elevator system, and a dynamic braking resistor which is coupled between a third input terminal among the three input terminals of the three-phase power converter and the common DC bus.

The invention relates to the technical field of frequency converter control, in particular to a frequency converter control method, device and system, and the method comprises the steps: collecting the input and output current data of a frequency converter in real time; determining abnormal values of the input and output current data in each time period; determining the abnormal degree of the output current data in each time period based on the difference between the two abnormal values in each time period and the sudden change degree of the output current data in each time period; on the basis of the abnormal degree in each time period and the adjacent time period thereof and in combination with the difference of output current data between each time period and the adjacent time period thereof, determining the influence index of power supply fluctuation and electromagnetic interference in the control process of the frequency converter in each time period; and determining the power parameter of the power reaching law in the sliding mode controller in the frequency converter in the next time period. The invention aims to improve the buffeting suppression effect, maintain a good approaching speed and improve the control accuracy of the frequency converter.

The invention discloses a single-phase AC frequency converter input current obtaining method and device and a frequency converter, and the method comprises the steps: obtaining a DC bus voltage in a single-phase AC frequency converter, determining a load current and a bus capacitor ripple current according to the DC bus voltage, and determining a DC side current according to the load current and the bus capacitor ripple current; and determining the input current in the single-phase alternating-current frequency converter according to the direct-current side current. According to the application, the input current in the single-phase alternating current frequency converter can be obtained through the circuit parameters which can be directly obtained in the single-phase alternating current frequency converter, and the cost of obtaining the input current of the single-phase alternating current frequency converter can be greatly reduced.

Examples described herein provide a circuit that includes a power electronics converter disposed in a vehicle, the power electronics converter to receive alternating current (AC) electrical power from an AC grid source and to provide AC electrical power to an AC load external to the vehicle. The power electronics converter includes an AC-AC converter that includes a rectifier and an inverter, the rectifier being electrically connected to the inverter by a direct current (DC) link. The circuit further includes an on-board charging module electrically connected to the power electronics converter and a battery disposed in the vehicle. The power electronics converter provides vehicle-to-load functionality by providing, to the AC load, AC electric power as an output of at least one of a 120 Vac output or a 240 Vac output.

The invention discloses a self-adaptive photovoltaic power supply system, and relates to the field of photovoltaic power supply, the self-adaptive photovoltaic power supply system comprises a frequency converter and a photovoltaic direct current controller, the input end of the photovoltaic direct current controller is adaptively connected with a photovoltaic array, and the output end of the photovoltaic direct current controller is connected with the direct current input end of the frequency converter through a frequency converter direct current bus; the frequency converter is connected with a load; when the photovoltaic array works, a direct-current input voltage is generated and input to the photovoltaic direct-current controller, and the photovoltaic direct-current controller converts the direct-current input voltage into a direct-current output voltage matched with the direct-current bus voltage of the frequency converter so as to supply power to the frequency converter. The system can realize adaptive DC coupling of the photovoltaic DC controller and the frequency converter, and improves the efficiency of a photovoltaic power supply system.

The present invention relates to a submodule for a semiconductor transformer in single packaging with reduced partial discharge quantity and excellent insulation performance that is capable of applying an equipotential structure for each stage of the submodule for the semiconductor transformer to further improve insulation performance by reducing partial discharge quantity in the semiconductor transformer while improving insulation performance by securing separation distance between a high voltage unit and a low voltage unit in the semiconductor transformer. The submodule for semiconductor transformer in single packaging with reduced partial discharge quantity and excellent insulation performance in the present invention comprises: a high voltage unit for converting high-voltage low-frequency AC power into high-frequency AC power; a transforming unit for converting the high-voltage AC power into low-voltage AC power; and a low voltage unit for converting the low-voltage AC power into low-voltage DC power.

The invention discloses a high-power-density module for unidirectional power transmission and a modular medium-voltage frequency converter. The high-power-density module for unidirectional power transmission is composed of a grid-side full-bridge circuit, a high-frequency converter, an LC resonance branch, a multi-winding high-frequency transformer, a high-frequency diode circuit and a machine-side full-bridge circuit. A direct-current port of the grid-side / machine-side full-bridge circuit is connected with a direct-current port of the high-frequency converter and a direct-current port of the high-frequency diode circuit respectively, and an alternating-current port of the high-frequency converter and an alternating-current port of the high-frequency diode circuit are connected with a winding of the high-frequency transformer through LC resonance branches respectively. The modularized medium-voltage frequency converter comprises M high-power-density modules, and alternating-current ports of network-side / machine-side full-bridge circuits of all the modules are connected in series / in parallel to form a network-side three-phase alternating-current port and a machine-side n-phase alternating-current port. According to the invention, the number of IGBTs is effectively reduced, the capacitance value of the capacitor is reduced, and the size of the transformer is reduced, so that the transformer has the characteristics of low cost and high power density.

A microgrid comprises a meter adapter for interconnection to the electric grid, facility loads, and renewable energy resources using connectors, bus bars, and switches. Adapter connectors and internal bus bars and can be stressed with excessive heat rise from heat losses that arise from carrying high currents due to constraints in the physical size and airflow restrictions. Exhaust ports and / or vents are arranged to achieve a chimney cooling effect in such conditions to meet stringent UL requirements against resultant heat rise within a meter adapter.

A micro grid system comprises a secondary energy source and a power controller. The secondary energy source is associated with a micro grid that includes a fixed or mobile facility, and the secondary energy source is configured to generate first DC power signal. The power controller is in communication with the secondary energy source and an electric grid, and configured to receive first AC power signal from the electric grid and the first DC power signal from the secondary energy source and output a second AC power signal to loads in communication with the power controller. The power controller comprises an AC to DC frequency converter configured to change frequency and / or voltage of the second AC power signal, a processor, and a memory configured to store instructions that, when executed, cause the processor to control the frequency converter to change the frequency and / or voltage of the second AC power signal.

A noise reduction circuit includes: noise canceler circuitry configured to inject a compensation current into a power line and ground to reduce a common mode noise current that flows through the power line and the ground into a commercial power supply from a power converter with a switching element connected to the commercial power supply; and overcurrent inhibitor circuitry provided on a compensation current path through which the compensation current flows, the overcurrent inhibitor circuitry being configured to inhibit application of an overcurrent to the noise canceler circuitry.

Provided are a power supply circuit and a power supply system. In the power supply circuit, a main circuit output module includes a first DC / DC converter and a first DC / AC inverter, and a conversion module is configured to output DC power to the first DC / DC converter according to input AC power. The first DC / DC converter is configured to convert the DC power into a constant DC voltage, and output the constant DC voltage to a first DC / AC inverter. The first DC / AC inverter is configured to acquire first supplied electrical energy by converting the constant DC voltage into AC power, and output the first supplied electrical energy.

The invention provides a hybrid distribution transformer low-voltage turn-on overcurrent protection device and protection strategy combined with a current limiter, and the device comprises a hybrid distribution transformer which is composed of a power frequency electromagnetic part and a high-frequency power electronic part, and the power frequency electromagnetic part comprises a power transformer and a series transformer. The high-frequency power electronic part comprises converters which are connected back to back; the saturated iron core fault current limiter is integrated in a main loop of the hybrid distribution transformer, presents low impedance during normal operation, and is switched to a high impedance state through iron core desaturation to limit fault current during fault; the bypass switch module is connected to the input side of the high-frequency power electronic part, and when the fault current exceeds a set threshold value, the bypass switch module is conducted to bypass and isolate the high-frequency power electronic part within less than or equal to 1ms, and the continuous power supply of the power-frequency electromagnetic part is maintained; and the fault isolation device is configured at the two ends of the hybrid distribution transformer, and performs breaking operation in response to the current setting value and the low voltage setting value after current limiting so as to realize fault area isolation.

The invention discloses a radio frequency power supply for maintaining a remote plasma source, and the power supply comprises a three-phase rectification filtering module which is used for converting an obtained first AC electric signal into a DC electric signal, eliminating the noise and clutter interference in the DC electric signal, and providing a power signal for a subsequent circuit through the DC electric signal; the full-bridge LCL-T resonant inversion module is used for converting the direct-current electric signal into a second alternating-current electric signal with a preset frequency according to the pulse signal output by the driving control module and transmitting the second alternating-current electric signal to a load end; and the driving control module is used for outputting a pulse signal to control the full-bridge LCL-T resonant inversion module so as to realize a preset alternating current frequency. According to the radio frequency power supply for maintaining the remote plasma source, generation of plasmas can be maintained when the power supply frequency is at the preset power, the coupling efficiency of the power is improved, and heat generated in the operation process of the plasma source is reduced.

The invention relates to the technical field of electrical equipment testing, and discloses a high-precision anti-interference intelligent transformer short-circuit impedance testing machine which comprises an isolation power supply module and a testing host module, an electrostatic shielding layer is arranged in the isolation power supply module, a suspension working power supply isolated from power grid noise is provided for a testing host, and the anti-interference capability is improved from the source. The test host module integrates a power management and inversion module to generate a controllable three-phase AC excitation signal, and the central processing and control module performs closed-loop feedback control on a test current according to a high-precision synchronously acquired signal, so that an external voltage regulator is replaced, and automatic stabilization of a test condition is realized. According to the invention, tedious manual adjustment is not needed, full automation of the testing process is realized, and the precision, repeatability and safety of short-circuit impedance testing are remarkably improved.

The invention discloses a hybrid distribution transformer fusing an on-load tap changer and a series-parallel converter and a voltage control method, and belongs to the technical field of intelligent power distribution. The hybrid distribution transformer comprises a primary winding, a secondary main winding, a secondary series winding, an on-load tap changer, a series-parallel converter and a unified coordination controller, the parallel side of the parallel converter is connected to the output end of the secondary main winding, and compensation voltage is injected into the series side of the parallel converter through the secondary series winding. The voltage control is based on a voltage deviation and three-phase voltage unevenness hierarchical decision-making method, and the low-speed large-range voltage regulation of the on-load tap changer and the rapid and accurate compensation of the series-parallel converter are dynamically coordinated. The method has the high capacity advantage of an on-load tap changer and the quick response characteristic of a power electronic device, can synchronously solve the problems of long-term voltage deviation and instantaneous voltage fluctuation in the power distribution network, reduces the equipment cost and maintenance cost, and is suitable for voltage stabilization and electric energy quality optimization of the intelligent power distribution network.

The invention discloses an atmosphere plasma generator, which comprises a driving power supply and a spray gun, and is characterized in that the driving power supply comprises a rectifier, at least two half-bridge inverters and at least two transformers in one-to-one correspondence with the half-bridge inverters; the input end of the rectifier is connected with an AC power supply; the at least two half-bridge inverters are arranged at the output end of the rectifier in parallel; the primary side of each transformer is connected with the output end of the corresponding half-bridge inverter, the secondary sides of the multiple transformers are connected in series to form an output port, and the output port is connected with the spray gun. According to the atmospheric plasma generator, the specification requirement on a single related power device is reduced, so that higher total power output can be realized, the requirement of equipment such as the plasma generator on high voltage of several kilovolts can be met, and the controllability and adaptability of voltage output are improved. And when the power demand is increased, flexible expansion can be realized by increasing the number of the parallel modules, the whole system does not need to be redesigned, and the power expansion capability is improved.

The utility model discloses grid-connected and off-grid integrated test equipment for an energy storage system. The grid-connected and off-grid integrated test equipment comprises an input switch, an input filter, a rectifier, an inverter, an output filter, an AC / DC converter and a battery, the input end of the input switch is connected with a power grid, the output end of the input switch is connected with the input end of the input filter, the output end of the input filter is connected with the alternating-current side of the rectifier, the inverter is connected with the rectifier through a direct-current bus, and the alternating-current side of the inverter is connected with the input end of the output filter. The output end of the output filter is connected with the input end of the AC / DC converter through the grid-connected and off-grid mode change-over switch, the output end of the output filter is connected with the input end of the tested energy storage equipment, and the output end of the AC / DC converter is connected with a battery; according to the test equipment, the grid-connected and off-grid mode change-over switch is controlled, and the change of a control mode is matched, so that one set of equipment not only has a grid-connected test function of the energy storage system, but also has an off-grid test function of the energy storage system.

The invention discloses a grid-side current harmonic suppression method and device, a driving system without an electrolytic capacitor and a motor, and relates to the field of permanent magnet synchronous motor control, and the method comprises the steps: detecting the input admittance of a bus voltage inputted to a driving system, determining the harmonic frequency in the bus voltage needing to be suppressed according to the input admittance, and carrying out the suppression of the harmonic frequency; according to the harmonic frequency, required virtual impedance is applied to the two sides of the bus capacitor, and compensation voltage vectors corresponding to the virtual impedance are applied to the two ends of the capacitor so as to suppress the current of the harmonic frequency. Compared with a traditional motor driving scheme using an electrolytic capacitor, the method is applied to a non-electrolytic capacitor driving system, and the impedance of the driving system to specific frequency harmonics is increased by applying virtual impedance to the two ends of the capacitor, so that the grid-side current harmonics are reduced, and the robustness and dynamic performance of the system are improved.

A first controller includes a first processor and a first memory. A second controller includes a second processor and a second memory. In transmitting data from the first controller to the second controller, the first controller repeatedly performs a write operation of writing transmitted data into the first memory in accordance with a clock signal, and reads the transmitted data from the first memory and outputs the transmitted data. The second controller writes the received data into the second memory in accordance with the clock signal, and reads the received data from the second memory in accordance with the clock signal. When a plurality of data values of the received data read from the second memory match each other in a plurality of consecutive clock cycles including a current clock cycle, the second controller transmits the data value of the current clock cycle to the second processor.

The invention discloses an internal model control-based network construction type full-power wind power converter control method. The method comprises the following steps of: acquiring a control quantity of a network construction type full-power wind power converter; determining an active power current given value by using preset internal model control according to the control quantity; determining a modulation voltage of a wind power converter machine side converter according to an active power current given value by utilizing current loop control; utilizing direct-current voltage synchronous control, and outputting a control synchronous angle according to the control quantity; by means of voltage and current double-loop control, output control output voltage is output according to the control quantity; and realizing machine-side converter control of the wind power converter according to the modulation voltage, and realizing grid-side converter control of the wind power converter according to the control synchronization angle and the control output voltage.

The present invention relates to a submodule for a semiconductor transformer in single packaging with reduced partial discharge quantity and excellent insulation performance that is capable of applying an equipotential structure for each stage of the submodule for the semiconductor transformer to further improve insulation performance by reducing partial discharge quantity in the semiconductor transformer while improving insulation performance by securing separation distance between a high voltage unit and a low voltage unit in the semiconductor transformer.The submodule for semiconductor transformer in single packaging with reduced partial discharge quantity and excellent insulation performance in the present invention comprises: a high voltage unit for converting high-voltage low-frequency AC power into high-frequency AC power; a transforming unit for converting the high-voltage AC power into low-voltage AC power; and a low voltage unit for converting the low-voltage AC power into low-voltage DC power.

The invention discloses a frequency control method of a variable-frequency power supply. The method comprises the following steps: step 1, collecting multi-source information; 2, generating a dynamic frequency reference; 3, calculating a predictive control quantity; 4, self-adaptive compensation correction is carried out; and step 5, pulse width modulation output. The state of the variable-frequency power supply is sensed comprehensively through multi-source information collection, and data support is provided for accurate control; dynamic frequency reference generation and predictive control quantity calculation are adopted, rapid and accurate frequency control is achieved, and response delay and static errors are reduced; a self-adaptive compensation correction and pulse width modulation output mechanism is constructed, the adaptability to complex working conditions is enhanced, harmonic oscillation is suppressed, compared with the prior art, the response speed, the control precision and the adaptability are remarkably improved, and stable and efficient operation of the variable-frequency power source is guaranteed.

A resonant circuit arrangement according to the invention for a traction converter of a rail vehicle, wherein the traction converter has at least one grid-side first converter, at least one load-side second converter, a DC link connecting the at least one first converter and the at least one second converter with a first and a second voltage potential, and at least one DC link capacitor arranged in the DC link, is characterized in that the resonant circuit arrangement arranged in the DC link and connected in parallel to the at least one DC link capacitor comprises at least one switching arrangement including at least one switching unit and at least one inductor, wherein each switching unit comprises two terminals, at least two controllable power semiconductor switches and at least one switching unit capacitor, and is configureddepending on the switching positions of the power semiconductor switches, providing at least two different voltages at the terminals, and wherein the at least one inductor is connected in series with at least one switching unit, comprising at least one capacitive energy storage device, wherein the at least one capacitive energy storage device is connected in series with the at least one switching arrangement, and a control device, wherein the control device is configured to control at least the power semiconductor switches of the at least one switching unit.

The invention relates to the field of converters, and discloses a traction converter and a cooling system thereof, and the traction converter comprises at least one rectification module which is used for converting alternating current into direct current, and all bridge arms in the at least one rectification module can be equally divided into a first bridge arm group and a second bridge arm group; the at least two inversion modules are used for converting direct current into alternating current, each inversion module comprises a three-phase bridge arm, and all the bridge arms in the at least two inversion modules can be equally divided into a third bridge arm group and a fourth bridge arm group; the first cooling plate is provided with a first rectification-inversion module, and the first rectification-inversion module comprises a first bridge arm group and a third bridge arm group; and the second cooling plate is provided with a second rectification-inversion module, and the second rectification-inversion module comprises a second bridge arm group and a fourth bridge arm group. In this way, the cooling system can be designed in a light-weight mode, and light weight of the traction converter is achieved.

The utility model discloses a low-power-consumption high-efficiency main transformer integrated board for an air-cooled refrigerator, which comprises an X capacitor discharge circuit, a variable-frequency power supply circuit, a bus voltage sampling circuit, a mains supply voltage sampling circuit and an IGBT (Insulated Gate Bipolar Translator) driving circuit, and is characterized in that the X capacitor discharge circuit uses a discharge chip to replace a traditional discharge resistor; the variable-frequency power supply circuit is additionally provided with a variable-frequency power supply switch circuit, the bus and commercial power voltage sampling circuit modifies the resistance value of a divider resistor, and the IGBT driving circuit modifies the resistance value of a resistor. According to the utility model, improvement is made on the basis of a traditional air-cooled refrigerator main transformer integrated plate, the standby power consumption and the operation power consumption of the main transformer integrated plate are reduced, and the low-power-consumption and high-efficiency electric control design is realized.