70 results about "Active front end" patented technology

An apparatus for DC fast charging of an electric vehicle includes an active front end AC-DC converter and an isolated DC-DC converter. The active front end AC-DC converter is adapted to rectify a medium voltage alternating current (AC) from a utility grid to a high voltage direct current (DC). The isolated DC-DC converter is adapted to transform the high voltage DC to a low voltage DC for charging the electric vehicle.

A photovoltaic (PV) integrated variable frequency drive system having a variable frequency drive and an energy source. The variable frequency drive having a back end inverter, a DC bus electrically connected to the back end inverter, and an active front end electrically connected to the DC bus to facilitate bi-directional power flow to and from a power grid. The energy source being electrically connected to the DC bus.

A power converter includes an active front end (AFE) that is coupled by a dc link stage to a plurality of H-bridge inverters. One or more multi-phase electro-magnetic energy conversion devices, such as transformers or electric machines, with open windings that are connected to only the AFE or only the H-bridge inverters or to both the AFE and H-bridge inverters, provide a regenerative or partial regenerative power converter.

A communication system includes a conversion module configured to convert a signal between a radio frequency baseband (RF-BB) and an intermediate frequency (IF). At least one RF front-end module converts the signal between the IF and a radio frequency (RF). The RF front-end module is configured as an RF phased array and includes a coaxial interconnect configured to connect the conversion module with the RF front-end module. The signal is transmitted between the conversion module and the RF-front end module via the coaxial interconnect. At least one RF front-end module includes an active front-end (AFE) configured to allow the signal to be transmitted via the coaxial interconnect while minimizing any deterioration of the signal.

The invention relates to a novel active front-end controller topological structure which comprises a dual buck / boost type AC / DC converters and a DC CLLC resonant converter. The novel active front-end controller topological structure is characterized in that the dual buck / boost type AC / DC converters and the DC CLLC resonant converter serve as core constituent parts of an AFEC body topological structure and are formed by combining an input series-connection mode and an output parallel-connection mode, and mutual power conversion between a medium-voltage alternating-current power distribution network and a low-voltage alternating-current power distribution network is achieved by utilizing a power electronic technology and a high-frequency isolation technology. In addition, voltage regulation control is conducted on a low-voltage direct-current side busbar to achieve power balance of the medium-voltage alternating-current side and the low-voltage direct-current side. Functions of reactive compensation, active filtering, bidirectional power conversion and the like can be achieved according to different actual requirements. The novel active front-end controller topological structure can fully play the potential value of an active front-end controller, has high reliability and system efficiency and good modularity and meets different voltage class requirements.

A dragline excavating machine includes a gearless direct drive AC drive motor for driving each of the hoist and the drag drums in the system. The gearless AC motor is driven using a digital system which receives AC power from the utility system rectifies the power using active front end circuits, and converts the resultant DC to a frequency controlled AC using an inverter circuit. The resultant AC signal is employed to drive the gearless AC motor, resulting in reduced harmonic distortion, unity or leading power factor, and increased efficiency, reduced operating costs, and reduced mean time between failure.

An adjustable frequency drive includes a base having a first portion and a second portion, and an active front end converter disposed on the base. The converter includes an input, an output, and a plurality of first electronic switches electrically connected between the input and the output. An inverter is disposed on the base and includes an input electrically connected to the output of the active front end converter, an output, a plurality of capacitors disposed on the first portion of the base and electrically connected to the input of the inverter, a plurality of second electronic switches disposed on the second portion of the base and electrically connected between the input and the output of the inverter, and a heat pipe assembly. The inverter is structured to provide a single, three-phase output structure.

This application describes a dynamically tuned front end module using a modal antenna approach for improved communication system performance. The front end module consists of power amplifiers, filters, switches and antennas along with tuning circuits integrated and controlled to provide an optimized system for RF transmission. Dynamic tuning provides the ability to maintain optimized system performance for a wide variety of use cases and environments that the wireless device is operated in. Several transmission modes are accessed in an algorithm to optimize the performance of multiple wireless devices in a cellular system, to include a power conservation mode, emergency transmission mode, and cell capacity optimization mode. Dynamic adjustment of correlation and isolation between multiple antennas is a benefit provided by this front end topology.

A power converter includes an active front end (AFE) that is coupled by a dc link stage to a plurality of H-bridge inverters. One or more multi-phase electro-magnetic energy conversion devices, such as transformers or electric machines, with open windings that are connected to only the AFE or only the H-bridge inverters or to both the AFE and H-bridge inverters, provide a regenerative or partial regenerative power converter.

This application describes a dynamically tuned front end module using a modal antenna approach for improved communication system performance. The front end module consists of power amplifiers, filters, switches and antennas along with tuning circuits integrated and controlled to provide an optimized system for RF transmission. Dynamic tuning provides the ability to maintain optimized system performance for a wide variety of use cases and environments that the wireless device is operated in. Several transmission modes are accessed in an algorithm to optimize the performance of multiple wireless devices in a cellular system, to include a power conservation mode, emergency transmission mode, and cell capacity optimization mode. Dynamic adjustment of correlation and isolation between multiple antennas is a benefit provided by this front end topology.

The invention relates to a high-power three-level converter temperature rise and loss testing method employing an active front end. The method is characterized by comprising the following steps of: (1) connecting a low-capacity reactor between a rectifying unit and an inverter unit of a frequency converter, and connecting a low-capacity direct-current power supply to a middle direct-current side of the frequency converter, and (2) setting the rectifying unit to operate in an inverter manner, setting an output voltage reference value of the rectifying unit and the output voltage reference value of the inverter unit at fixed values, adjusting the current which flows through the reactor, and simulating different work conditions and comprehensively testing the loss and temperature rise of the frequency converter under different work conditions by adjusting the magnitude of the output power and the power factor of the inverter unit so as to accurately estimate the output of the device. According to the invention, high-powder three-level frequency converter temperature rise and loss testing functions can be achieved by only one low-capacity reactor and one external low-capacity direct-current power supply. The method has the advantages of simple structure, accurate result, fewer used auxiliary apparatuses, easy realization and the like.

An active front-end rectifier filter delay compensation method based on model predictive control is disclosed. The method includes following steps: detecting a three-phase grid voltage and three-phase input current sampling value of an active front-end rectifier, and transforming both via Clarke transformation to acquire grid voltage sampling values eα and eβ, and input current sampling values ifα and ifβ under a two-phase stationary coordinate system; establishing an equivalent mathematical model of rectifier on the basis of voltage balancing equation (1) in an actual rectifier, and establishing an equivalent filter model on the basis of a transfer function corresponding to the actual filter, thus constituting a filter delay observer; and, compensating the difference value between the input current sampling values ifα and ifβ, and equivalent current sampling values iofα and iofβ into an input of the filter delay observer via a proportional controller. In comparison to the input current sampling values ifα and ifβ, the input current observed values ioα and ioβ of the rectifier are not impacted by a filter latency and are closer to the actual input current value of the rectifier such that the impact of the filter delay is compensated.

Power conversion systems and operating methods are presented in which an active front end rectifier is operated in a boost mode using discontinuous pulse width modulation in a first range of DC bus voltage boost amount, and continuous space vector pulse width modulation is used in a second range, with the ranges being correlated to output derating with respect to filter inductor magnetics in the first range and to rectifier switching loss derating and the second range.

Embodiments herein relate to a rectifier to supply a DC bus that in turn supplies voltage to a converter that drives a motor and configuring the rectifier to minimize or eliminate common mode voltage between the DC bus and the AC source. In this way, the embodiments herein relate to timing and switching a power from the rectifier to the DC bus.

The invention discloses a five-level high-efficiency rectifier suitable for single-phase and three-phase structures. The five-level high-efficiency rectifier comprises a DC power supply and a voltagedividing capacitor module, and each phase of circuit comprises two silicon-based diode modules, an absorption capacitor, a flying capacitor, two silicon carbide based metal-oxide-semiconductor field-effect transistor modules and a filtering inductor. The rectifier is characterized by low switching loss due to the fact that only silicon carbide based metal-oxide-semiconductor field-effect transistors have high-frequency switching, compared with a full silicon carbide based rectifier, silicon-based power diodes are used, and the total cost is lower; and compared with two or three level circuit,five-level rectification can be realized and popularized to intermediate-voltage application. The rectifier is suitable for active front-end occasions of high-voltage large-power application.

The present invention provides a power distribution system such as a marine power distribution and propulsion system (20). The system includes an ac busbar (2) and a plurality of active front end (AFE) power converters (4, 22). Each AFE power converter (4, 22) includes a first active rectifier / inverter (6) connected to the busbar (2) and a second active rectifier / inverter (8) connected to an electrical load such as an electric propulsion motor (M1...M4). Power sources (PS1...PS3) are connected to the dc link (24) of the AFE power converters (22) and can be operated under the control of a power management controller or power management system (PMS).

The invention relates to a load test device for a large-power frequency converter adopting a front active end. The main technical characteristics are that: the load test device comprises a frequency convertor, a reactor and a direct-current power supply; the reactor is connected between a rectification unit and an inversion unit of the frequency convertor; the front active end is adopted by the rectification unit; and the direct-current power supply is connected with the middle direct-current side of the frequency convertor to ensure that the rectification unit, the middle direct current side, the inversion unit, and the reactor form a power loop. The load test device has reasonable design, and can be implemented by only one reactor with small capacity, and an externally connected power supply with small capacity; and other power consumption except loss on a power device and a line is avoided in the whole test process, and large-power current can pass through the frequency convertor only taking a small amount of energy from a power grid, so that the function that a power grid with small capacity is subjected to load test of the large-power frequency converter can be realized, and the load test device has the advantages of simple structure, accurate test result, few auxiliary appliance and the like and is easy to implement.

The invention discloses a two-motor driving type cascading multi-level inverter system without an active front end and a control method thereof. The system comprises an energy feedback coupling unit arranged between a power unit of a first cascading multi-level inverter and a power unit of a second cascading multi-level inverter, wherein the energy feedback coupling unit comprises a first inverter circuit, a second inverter circuit, a middle direct voltage capacitor, a current reversible chopper circuit, a buffering inductor, a buffering resistor and a storage battery, the current reversible chopper circuit comprises a buck chopper circuit part and a boost chopper circuit part, the switching between the buck chopping mode and the boost chopping mode is achieved according to the voltage between the two ends of the middle direct voltage capacitor, and then energy can be fed back to the storage battery and recycled to drive motors to run. According to the system, a bidirectional transducer based on a three-phase PWM rectifying circuit is not needed, winding remaking of a phase-shifting transformer is avoided, the energy feedback coupling unit does not need to be connected with a power grid, the complexity and cost of the system can be reduced, energy feeding and harmonic wave injection to the power grid are avoided, and the system is suitable for large-scale application.

Apparatus and methods are provided for detecting degradation of delta-connected filter capacitors in an active front end (AFE) power converter, in which delta circuit capacitor leg currents are calculated based on measured branch circuit currents, and filter capacitor impedance values are computed based on the calculated leg currents as well as measured line-to-line voltages and corresponding phase angles for comparison with one or more thresholds to selectively detect degradation of the filter capacitors. Further apparatus and methods are provided for detecting degradation of Y-connected filter capacitors by computation of fundamental frequency RMS impedance values as ratios of RMS capacitor voltages and RMS circuit branch currents, and comparison of the calculated RMS impedance values with one or more thresholds.

The invention relates to a rated capacity test method of an active front end voltage-type alternating current-direct current-alternating current frequency converter. The method is technically featured by comprising the steps as follows: (1) accessing an active front-end rectifier AFER and an inverter INV of the frequency converter to a power grid to form a closed-loop testing circuit through a transformer unit, respectively; (2) building a test control system in an independent vector control manner of active power and reactive power; and (3) flexibly adjusting the magnitudes of the power and an output power factor of the frequency converter by adjusting related settings of the AFER and the IVN, carrying out reversible operation tests of rated capacity under different power factors, and testing rated capacity of the complete set of frequency converter and temperature rise of a power apparatus. The method, disclosed by the invention, has rational design. The reversible operation tests of the rated capacity are carried out under different power factors by adjusting output settings of the active front-end rectifier and the inverter as well as the output power magnitude and the power factor of the frequency converter, and the rated capacity of the complete set of frequency converter and the temperature rise of the power apparatus are accurately tested.

The present invention relates to a rated-capacity test device for an active front-end voltage type AC-DC-AC frequency converter. The test device is mainly and technically characterized by comprising a frequency converter, a transformer device and a power grid, wherein an active front-end rectifier AFER and an inverter INV of the frequency converter are cut into the power grid through the transformer device; and by adjusting related settings of AFER and INV, the power and the output power factor of the frequency converter can be adjusted flexibly, so that reversible operation tests for the rated capacity with different power factors can be carried out and the rated capacity of the whole frequency converter and the temperature rise of power devices can be tested. The test device is designed reasonably; and by adjusting the output settings of the active front-end rectifier and the inverter as well as the output power and the power factor of the frequency converter, reversible operation tests for the rated capacity with different power factors are carried out, so that the rated capacity of the whole frequency converter and the temperature rise of power devices can be accurately tested.

A photovoltaic (PV) integrated variable frequency drive system having a variable frequency drive and an energy source. The variable frequency drive having a back end inverter, a DC bus electrically connected to the back end inverter, and an active front end electrically connected to the DC bus to facilitate bi-directional power flow to and from a power grid. The energy source being electrically connected to the DC bus.

The invention provides a product quality aging testing system, which comprises a transformer and an active front end convertor. The transformer is used for supplying power to at least one kind of electronic product, and the active front end convertor is electrically coupled with the transformer and the electronic product to recover electric energy outputted from the electronic product into the input terminal of the electronic product. As the average recovery efficiency of the active front end convertor is about 80 percent, the product quality aging testing system can achieve considerable technical advancement, has a wide utilization value in the industry, and at least has the advantages of saving energy, enhancing capacity, improving utility power quality, reducing transformer load, improving equipment stability, reducing load cost and the like.

Methods and systems are disclosed for detecting capacitor degradation in an input filter of an active front end power conversion system in which voltage and current sensing is performed to determine sequence component impedance asymmetry to detect filter capacitor degradation according to the value of an off-axis admittance matrix component for Delta or Y-connected filter capacitor banks without sensitivity to voltage unbalance, and with the capability to identify particular degraded capacitor locations based on individual impedance values.

The invention discloses a high-efficiency rectifier comprising a direct-current power supply, a voltage-dividing capacitor module, two silicon-based diode modules, an absorbing capacitor, a silicon-carbide-based metal-oxide-semiconductor field-effect transistor and a filter inductor. The rectifier is characterized in that only the silicon-carbide-based metal-oxide-semiconductor field-effect transistor has the high-frequency switching action, so that the switching loss is low; and compared with the full-silicon-carbide-based rectifier plan, the high-efficiency rectifier employs the silicon-based power diode, so that the overall cost is lowered. The rectifier is suitable for intermediate-voltage and high-voltage high-power active front-end application occasions.

The invention discloses an RS485 bus short circuit isolator, which relates to the technical field of communication and solves the problem of short circuit isolation among branches of common RS485 bus-based firefighting. The RS485 bus short circuit isolator comprises a first electrical interface, a short circuit automatic isolating module of a passive signal and a second electrical interface, wherein the short circuit automatic isolating module of the passive signal comprises a drive trigger unit, a switch drive unit and an RS485 bus switch unit. The RS485 bus short circuit isolator can also adopt the following structure that: the isolator comprises the first electrical interface, an active front end data transceiver module, an active rear end data transceiver module, an automatic transceiver control module, the second electrical interface and a voltage-stabilizing power supply module. The invention is applied to an RS485 bus firefighting network.

The invention discloses an implementation method of a thyristor-based high-quality active front-end converter, belongs to the alternating-current converter control technology, and aims to intensively study the rectification system conversion mechanism of a frequency converter, a topological structure and a control technology and develop a thyristor-based high-quality active front-end converter with low harmonic wave, high power factor and electric power feedback capacity. The implementation method of the thyristor-based high-quality active front-end converter is characterized in that an active front-end conversion system of the converter comprises a phase-shifting transformer, a 12-pulse bridge inverter and a multi-level direct current control and synthesis unit, wherein the 12-pulse bridge inverter is formed by two completely identical 6-pulse thyristor bridge inverters. An asymmetrical current control strategy is adopted, two three-phase bridge inverters are controlled according to a given conversion rule, so that current on line side of the phase-shifting transformer is sine-wave current, the functions of low harmonic wave, free adjustability of a power factor, electric power feedback brake, adjustable large range of direct-current voltage and current are realized, and the method is applicable to green and energy-saving type active front-end converters with various voltage classes and various power ranges.

The invention discloses a multifunctional electric propulsion diving and ROV (remote-operated vehicle) support boat which comprises a boat body. Rectangular planar passive anti-rolling water chambersare formed in a boat bow and the middle of the boat body, a propulsion device is mounted on the boat body and is electrically connected with an electric power system, the electric power system mainlycomprises a main power station, two full-circle swinging propellers MT, three pipeline-type side propellers BT, five diesel generating sets DG, a berth generating set HG, an emergency generating set EG and a diving emergency generating set, the main power station is electrically connected with the five diesel generating sets DG, and the five diesel generating sets DG is named as a main generatingset DG1, a main generating set DG2, a main generating set DG3, a main generating set DG4 and a main generating set DG5. By the aid of a electric propulsion system of an active front-end frequency conversion control technique, propulsion power is high, the electric propulsion system occupies less space in the boat, and safety, multifunctionality and comfort of the boat body are obviously improved.

The invention discloses an AC / DC (alternating current / direct current) convertor implementation method based on an asymmetrical multi-level synthesis technology, belongs to an AC / DC conversion and control technology related to the electrical technology, and aims to research develop an AC / DC convertor which has low harmonic wave and high quality and is suitable for application requirements for various capacities. The AC / DC convertor implementation method is characterized in that the traditional mode that current of a 12-pulse-wave AC / DC convertor is symmetrically distributed to two three-phase bridge inverters for conversion is replaced with the novel method that the current is asymmetrically distributed to two three-phase bridge inverters, direct current is distributed to the two three-phase bridge inverters according to a given conversion rule, so that three-phase alternating current of an incoming line of the convertor is sine-wave current, then an equal-increment step-shaped triangular wave current waveform is adopted for approximate substitution of ideal transformation, and the AC / DC convertor implementation method based on the asymmetrical multi-level synthesis technology has the characteristics of low harmonic wave, thyristor controllability, lead-lag continuous adjustment of a power factor, high combined efficiency of a system and suitability to application requirements for various capacities and can be applied to direct-current power sources with various capacities and active front-end converters with various applications.

Certain exemplary embodiments comprise a system comprising a plurality of Active Front End units adapted to be electrically coupled to a direct current (DC) bus. Each of the plurality of Active Front End units can be adapted to be electrically coupled to a separate winding of a transformer of a plurality of transformers. Each of the plurality of Active Front End units can be adapted to convert alternating current (AC) voltage to a DC voltage. Each of the plurality of Active Front End units can be adapted to supply the DC voltage to the DC bus. The DC bus can be adapted to be electrically coupled to a plurality of inverters.