150 results about "Three phase converter" patented technology

A galvanic isolated DC-DC and DC-AC power conversion system is coupled to a plurality of DC sources which are derived from a combination of a plurality of single-phase and three-phase AC-DC converters. The DC-DC and DC-AC power conversion system in one embodiment is configured to provide mixed type outputs (mixed frequency, e.g. DC with 50 or 60 Hz, with 400 Hz; mixed voltage levels).

The invention relates to a series resonance DC / DC converter of a photovoltaic system, which comprises a single-pole converter (40), a series resonance circuit (50), a high-frequency isolation transformer (16) and a rapid uncontrollable rectifier (20), wherein the single-pole converter (40) is used for converting a direct voltage (26) of a photovoltaic array (10) into a single-pole pulse voltage; the series resonance circuit (50) is used for converting the single-pole pulse voltage into a sine voltage with a fixed frequency; the high-frequency isolation transformer (16) is used for boosting and isolating as well as protecting; and the rapid uncontrollable rectifier (20) is used for rectifying the high-frequency sine voltage into a stable direct current voltage (28). The converter (100) is only provided with two switching elements, has the advantages of simple control mode and no switching loss, and can be used for boosting and stabilizing the larger photovoltaic array so as to be convenient for synchronizing through a three-phase converter or charging a storage battery.

In compensating for unbalanced voltages of three-phase AC, instantaneous values of wye-phase voltages 120° out of phase with each other are obtained from line voltages using a centroid vector operation, symmetrical component voltages of three-phase balanced system are obtained from the instantaneous values of wye-phase voltages, a compensation signal to compensate unbalanced voltages of three-phase AC is generated from zero-phase-sequence voltage of symmetrical component voltages is generated, wye-phase voltages 120° out of phase, the unbalanced voltages of which are compensated, are obtained from the compensation signal and the symmetrical component voltages, a control signal of a PWM conversion is generated based on the compensated wye-phase voltage compensated, and the unbalanced voltages of three-phase AC are compensated. The amount of time to compensate the three-phase unbalanced voltages required for detecting an unbalance of voltages and generating a control signal can be shortened.

In power conversion according to the three-phase converter, symmetrical component voltage values of a balanced system are calculated from wye-phase voltages on the three-phase AC input side of the three-phase converter. On the DC output side thereof, the power factor is set, an average active power value is calculated from an output voltage value and an output current value, and an average reactive power is calculated from the set power factor. On the basis of the symmetrical component voltage values, the average active power, and the active reactive power, a compensation signal for compensating for unbalanced voltages of the three-phase AC voltages and a control signal for controlling the power factor are generated, and according to the compensation signal and the control signal, a control signal for outputting DC is generated.

Single-phase to three-phase converter comprising a rectifier stage, a DC link and an inverter stage, wherein the rectifier comprises a filter choke, one controllable switch for power factor correction, rectifying diodes arranged in a diode bridge configuration having input terminals and output terminals, the controllable switch being connected to the output terminals of the diode bridge, an upper blocking diode arranged between the positive output terminal of the diode bridge and the positive input of the DC link and a lower blocking diode arranged between the negative output terminal of the diode bridge and the negative input of the DC link, the DC link comprises a capacitor bank connected between the DC link, which capacitor bank has a center point. The inverter stage comprises three phase outputs, two of which are formed with a series connections of controllable switches arranged between the DC link for switching either positive voltage or negative voltage of the DC link to the phase outputs, and one phase output is formed of the voltage of the center point of the capacitor bank, and in that the center point of the capacitor bank is configured to be optionally connected to the neutral line of the single-phase AC input by using a connection switch element providing thereby doubled voltage to the DC link.

A non-outage power supply system comprises three-phase ac input terminals and three-phase ac output terminals, between which there are sequentially connected a three-phase ac-to-dc converter circuit, a capacitor, and a three-phase dc-to-ac converter circuit. A bypass switch is connected between a preselected one of the three-phase ac input terminals and a preselected one of the three-phase ac output terminals. A bypass switch control circuit holds the bypass switch closed when the three-phase ac inputs are in phase with the three-phase ac outputs, and open when they are not. Part or all of the effective current demanded by the load bypasses the three-phase dc-to-ac converter circuit when the bypass switch is closed, with a consequent reduction of power loss.

The invention discloses an electric vehicle driving and charging system with fault tolerance and a fault reconstruction method. The system comprises a vehicle battery, a dual three-phase converter, an open winding motor, fault-tolerant switches, and charging switches. The vehicle battery is connected to the DC side of the dual three-phase converter. The open winding motor is of a split winding structure. The center point of each phase of winding is connected to the corresponding charging switch. The fault-tolerant switches are connected to the two ends of the corresponding phase of winding of the open winding motor. During normal operation, the vehicle battery controls the open winding motor through the dual three-phase converter to realize a driving function. Three-phase AC power is reversely fed by the dual three-phase converter to charge the battery through the charging switches and the open winding motor of a split winding structure. In the fault-tolerant operation process, after an open-circuit fault of one or two phases of bridge arms of the dual three-phase converter, the corresponding fault-tolerant switches reconfigure the topology of the dual three-phase converter. Through corresponding driving and charging control, the functions of driving and charging after system fault tolerance are realized.

Multilevel high power converters, referred to as hexagram converters, which preferably include a combination of six three-phase converter modules, are provided herein. The three-phase converter modules are interconnected and can be configured as any three-phase converter for any given application. One or more inductors can be used in the interconnections between the six modules to suppress potential circulating currents. Numerous applications exist in which the described converters can be implemented.

A small signal feedback loop or feed-forward loop having gain provides substantially unconditional instability in a phase locked loop when a reference phase signal is lost. The small signal feedback or feed-forward also modifies phase locked loop bandwidth when the reference phase signal is lost to increase rapidity of response to loss of reference phase signal while maintaining insensitivity to reference voltage amplitude change while the reference phase signal is present. The performance thus achieved is particularly suitable for rapid condition detection response and control of a grid connected power converter under islanding conditions.

An open-phase detecting method wherein a simple hardware structure is used to achieve a reduced cost: the IRQ member is reduced to reduce the load on a CPU; the open phase detection is performed in two items, that is, a phase difference and a voltage sign to reduce the possibility of occurrence of erroneous detections; and any phase that is open can be also determined. In the method for detecting any open-phase of the power supply of a three-phase converter, a neutral point N1 is connected to a negative pole side bus N of the DC side output of the rectifying means; an end of the first resistor of each phase, which connects the first resistor to the second resistor of each phase, is connected to an AD converter via a high input impedance means of the respective phase to detect the voltage of the respective phase; the voltage of the respective phase is outputted to a CPU that serves as an open-phase detecting means; and an open phase is detected when the sings of two of the three line voltages determined based on the voltages of the respective phases are different from each other and a phase difference thereof exhibits a half-wave rectification waveform of 180°.

The invention discloses an electromagnetic transient mathematical model of a distributed power-flow controller based on an MMC, control system and a modeling method. The distributed power-flow controller comprises a parallel connection side converter composed of a three-phase converter based on the MMC at the parallel connection side and a parallel connection side single-phase converter and a series connection side converter composed of multiple sets of series connection side single-phase converter; the electromagnetic transient mathematical model mainly comprises a parallel connection side converter model and a series connection side converter model; the control system comprises a parallel connection side control model and a series connection side control model, the parallel connection side control model comprises a three-phase converter control module based on the MMC at the parallel connection side and a parallel connection side single-phase converter module, and the series connection side control model comprises a series connection side third harmonic control module and a series connection converter active power reactive power control module. The electromagnetic transient mathematical model is designed by adopting modularization, the sub module switch-on and switch-off frequency is lowered, and the loss is lowered; the control system adapts to different voltage grades, and is applicable to flexible alternating current transmission occasions.

Disclosed is a flux controller for maintaining reliable flux estimation performance in a low velocity region, the controller including a velocity controller, a torque current controller for outputting a torque voltage command, a flux controller for outputting a flux current command, a flux current controller for receiving the flux current command to output a flux voltage command, a three-phase converter for converting the torque voltage command and the flux voltage command into a three-phase voltage command applied to the induction motor to output the three-phase voltage command, a flux estimator for outputting a rotating angle of a rotor of the induction motor, an estimated flux value of the rotor and an estimated velocity of the rotor, and a flux regulator for receiving the torque voltage command and the estimated velocity to output a gain value that regulates a magnitude of the flux command.

The invention discloses a multifunctional power distribution net flexible grounding device and a control method. The device is arranged on the side of an electricity generator and a power distributionnetwork transformer secondary side or a power distribution network busbar side; the device comprises a three-phase converter and a controllable switch, and the neutral point of the three-phase converter can be grounded through the controllable switch; the device works in the reactive compensation mode under the normal condition, when a single-phase grounding fault of the power distribution net happens, the controllable switch is closed, the device injects zero-frequency / common mode current or zero frequency / common mode voltage into a power distribution network three-phase circuit so as to achieve the purposes of single-phase grounding fault arc extinction and fault positioning, and the reactive compensation, single-phase grounding fault arc extinction and fault positioning functions can be enabled at the same time. The reactive compensation, circuit grounding parameter measurement, arc extinction, fault line selection, positioning and other functions can be integrated into the same device, the reactive compensation function can be normally enabled while the single-phase grounding arc extinction, single-phase grounding line selection, positioning and other functions are achieved, and multiple purposes of the device are truly achieved.

A device for preventing bearing damage from currents through a three-phase motor is provided, including a shield for winding and copper wire within each stator slot of a motor. The shield includes an electrically conductive layer which is insulated from the winding and from the laminated stator core of the three-phase motor. The conductive layer is grounded or conductively connected to the laminated stator core of the three-phase motor on only that side on which the three-phase current is fed to the winding of the motor.

A multilevel converter for controlling a multilevel converter is provided. The multilevel converter is a single phase converter with one phase leg, or a three phase converter with three phase legs, the phase legs of the three phase converter are interconnected in a star-configuration. The single phase converter with one phase leg, or each three phase converter with three phase legs, phase leg includes switching cells, and each switching cell includes semi-conductor switches arranged to selectively provide a connection to a corresponding energy storage element. The converter also includes a controller, which is provided to monitor the DC voltage of the energy storage elements, and the controller is provided to control the switching of each switching cell. The phase leg of the single phase converter, or each phase leg of the three phase converter, includes two parallel branches of switching cells, the branches being configured in a closed circuit.

The invention discloses a controlling and optimizing method of s grid-combining three-phase voltage source converter in an accumulator storage system, belonging to the field of electricity storage. The method comprises the following steps of: collecting signals of voltage and the three-phase electric grid current, performing Clark conversion and Park conversion to convert into two-phase fixed axis variable using as a feedback quantity, and counting charging power, comparing the feedback power with reference power, performing PI regulation and then outputting, wherein the output value is a reference value of active current, synchronously setting a reference value of passive current, comparing the reference values of the active current and the passive current with a rotating shaft two-phase current which is converted from the three-phase electric grid current, and performing the PI regulation to obtain a reference voltage, performing the Clark reverse conversion and the Park reverse conversion to obtain the fixed coordinate system voltage of the output end of the three-phase converter. The controlling and optimizing method of grid-combining three-phase voltage source converter in accumulator storage system can directly control the grid-combining active power of the converter, thus the loop is simple to control, the three-stage system is changed into a two-stage system, the system is easy to optimize and the system is stable and reliable.

Systems for converting single phase power to three phase power are well known, however, these systems may be noisy and wasteful of electrical power because they are prone to being left on for long periods of time when three phase power is not required. To overcome these disadvantages, these converters would be manually started and stopped as necessary. This invention solves these problems by providing a system that automatically controls a three phase converter based on electrical characteristics of the connected three phase load. The invention may detect when a three phase load requires power to operate and enables a three phase converter to provide the required power. Upon completion of the requirement of power, the system of the invention may shut down the converter. Additionally, the system of the invention may signal other electrical devices based on various electrical conditions of the connected three phase load.

The invention is an energy quality controller for a traction power substation, composed of a three-phase converter and a Scott transformer, two orthogonal single-phase output power supplies are connected with two single-phase output ends of the Scott transformer, respectively, the three-phase converter connects in series with a three-phase output end of the Scott transformer, where the three-phase converter is an inverter with capacitor in parallel with the DC bus. It controls two power supply arms of the traction transformer at the same time and can effectively compensate harmonics in drawing electric network, reactive power and negative sequence current.

The present invention provides a modulation controller for use with a three phase converter. In one embodiment, the modulation controller includes a three phase modulator configured to provide vector control signals for the three phase converter that generate a common mode voltage. Additionally, the modulation controller also includes a transition modifier coupled to the three phase modulator and configured to provide a shaping function for the vector control signals that extends a transition period of the common mode voltage.

The invention relates to a testing system of a hybrid power motor and a testing method thereof, wherein an engine, a motor and a power assembly of a gear box are assembled on the production line by one time; the power assembly is directed transported to a testing bench; firstly, the calibration of a motor position sensor is conducted; next, the reliability test of the motor is conducted; the testing system is provided with a calibration controller which conducts the calibration to the motor position sensor; the testing system also comprises a direct-current power cabinet, a PC computer, a three-phase converter box and a safety micro-control switch, wherein the phase a, the phase b and the phase c of the motor are connected with the calibration controller by the three-phase converter box; the calibration controller is electrified by the direct-current power cabinet and conducts communication with the PC computer by a CAN wire; the PC computer controls the power cabinet by a communication wire; simultaneously, the power cabinet can be controlled by a safety loop and the safety micro-control switch.

The present invention discloses a five-bridge arm converter-based open winding permanent magnet synchronous motor driving system and method. A five-bridge arm converter comprises a six-switch three-phase converter and a four-switch single-phase converter which are connected in parallel, the output end of the six-switch three-phase converter is connected with the left-end windings A,B and C of an open winding permanent magnet synchronous motor, the output end of the four-switch single-phase converter is connected with the right-end windings A' and C', and a right-end winding B' is connected with a left-end winding A. A current signal acquisition module is used to acquire a current signal of the open winding permanent magnet synchronous motor, a position signal acquisition module is used to acquire a voltage signal of the open winding permanent magnet synchronous motor, and the above current and voltage signals are both sent to a controller, thereby realizing the rotating speed current double closed loop control. A driving module outputs a PWM signal, thereby controlling the five-bridge arm converter. The system is low in cost and good in speed regulation performance. The present invention also discloses a five-bridge arm converter-based open winding permanent magnet synchronous motor driving method.

Disclosed are an apparatus and method for controlling a Direct Current (DC) / DC converter which controls energy flow between a first DC source and a second DC source to eliminate a high-frequency resonance. The apparatus for controlling the DC / DC converter includes a voltage controller, one or more subtractors, one or more fundamental component current controllers, a first coordinate transformer, a resonance current component extractor, a resonance frequency tracker, one or more resonance component current controllers, a second coordinate transformer, one or more adders and a Pulse Width Modulation (PWM) signal generation unit. The method implemented by the apparatus can effectively control any high-frequency resonance current components generated in the DC / DC converter.

The application discloses a fault ride-through control method for a variable-frequency transformer, which comprises the following steps: first, obtaining the voltage of a first grid, the voltage of asecond grid, the voltage of a stator and the current of the stator; then, calculating the voltage reference value corresponding to a single series three-phase converter after preprocessing; and finally, converting the voltage reference value into a control signal to control the series three-phase converter. The negative sequence voltage and negative sequence current of the stator caused by the negative sequence voltage of the first grid can be restrained, and the torque and power fluctuation of double rotor angular speed and double stator synchronization speed can be eliminated. The negative sequence current of the stator caused by the negative sequence voltage of the second grid can be restrained, and the electromagnetic torque and power fluctuation of double rotor synchronization speed can be greatly reduced. That is to say, the voltage imbalance problems of the left and right grids are solved at the same time by using a single series three-phase converter. Moreover, the grid cost isreduced. The application also discloses a fault ride-through control device, a circuit controller and a computer readable storage medium, which have the same beneficial effects.

The invention discloses a phase-locked-loop-free direct power prediction control method for a three-phase converter. The method is implemented under a synchronous rotating coordinate system, and no phase-locked loop is needed. According to the fact that a control system is delayed by two beats actually, sampling frequency which is two times of carrier frequency is adopted for reducing influences on prediction accuracy of the output power and current of the next beat and simplifying prediction calculation, complex calculation is not needed, the grid connection power, grid connection current and network voltage value of the next beat can be calculated accurately, control precision is improved, and output of a three-phase converter circuit of the next carrier cycle is obtained through calculation. The control method is simple and easy, fixed-frequency phase-locked-loop-free direct power prediction of the three-phase converter can be achieved, and the method is prone to engineering.

Systems for converting single phase power to three phase power are well known, however, these systems may be noisy and wasteful of electrical power because they are prone to being left on for long periods of time when three phase power is not required. To overcome these disadvantages, these converters would be manually started and stopped as necessary. This invention solves these problems by providing a system that automatically controls a three phase converter based on electrical characteristics of the connected three phase load. The invention may detect when a three phase load requires power to operate and enables a three phase converter to provide the required power. Upon completion of the requirement of power, the system of the invention may shut down the converter. Additionally, the system of the invention may signal other electrical devices based on various electrical conditions of the connected three phase load.