Abstract: A power conversion device includes a power conversion circuit, a memory, a voltage detection circuit, a current detection circuit, and a control circuit. The power conversion circuit controls a switching device based on a switching pulse signal to convert direct current power into alternating current power and output the alternating current power to a power supply target. The memory stores an alternating current phase difference. The voltage detection circuit detects an alternating current voltage effective value. The current detection circuit detects an alternating current effective value. Based on the alternating current phase difference, the alternating current voltage effective value, and the alternating current effective value, the control circuit stops output of the switching pulse signal at a time when an alternating current has a value of 0.

Abstract: Various voltage multipliers are disclosed for charging high voltage batteries and/or devices. The voltage multiplier includes an input node configured to receive an input voltage; an output node configured to output an output voltage, where the output voltage is greater than the input voltage. In some examples, an apparatus for the voltage multiplier is integrated with a soft switch device to receive antiphase pulsed inputs through a plurality of stages comprising MOSFETs, diodes, and/or full bridge rectifiers.

Abstract: A power converting apparatus includes: an inverter configured to convert input DC power into AC power by a switching operation; an output voltage detector configured to detect an output voltage of the inverter; and a controller configured to control the inverter. The controller is configured to perform proportional resonant control based on the output voltage, and output a switching control signal to the inverter based on the proportional resonant control. Accordingly, it is possible to remove harmonics generated due to connection of a nonlinear load.

Abstract: A high voltage offshore power plant power distribution assembly (100) comprising, at a subsea location, two end transformers (10a) and one or more intermediate transformers (10b), wherein the respective end transformers and intermediate transformers comprise a housing (11), a transformer core and winding assembly (13) comprising a plurality of sets of utility windings (15) and a set of collection windings (17), a plurality of utility terminals (19) connected to utility windings, wherein at least some of the utility terminals are connected to offshore power providers (1, 3). A collection line (28) connects to the set of collection windings (17). The respective end transformers and one or more intermediate transformers further comprise two collection terminals (29) and a collection line branching (27) located inside the housing (11). The collection line branching (27) connects the two collection terminals (29) to the collection line (28).

Abstract: A method for controlling an electrical transmission network including a plurality of DC high-voltage lines and at least three AC/DC converters which are identified by a respective index i and are interconnected by the DC high-voltage lines. Each of the AC/DC converts are connected to an AC voltage bus identified by a respective index i as well as to one of the DC high-voltage lines.

Abstract: A system includes a generator. Three AC feeders are connected for feeding AC output from the generator. A rectifier is electrically connected to the three AC feeders and to a load via a first DC feeder and a second DC feeder. A first resistor connects between a the first DC feeder and ground. A second resistor connects between the second DC feeder and ground. At least one of a first current sensor is operatively connected to detect current in the first DC feeder and/or a second current sensor is operatively connected to detect current in the second DC feeder. A controller is configured to monitor for changes in common mode current based on the input from the at least one current sensor, and to determine presence of a fault if change in the common mode current exceeds a predetermined threshold.

Abstract: The present invention discloses a calculation method for a converter valve state and a valve current based on temporal features of a valve side current, the process is follows: collecting three-phase AC currents, DC currents on a valve side of a converter of a DC transmission system, and trigger pulses of converter valves; establishing a node current equation of the AC currents and valve currents; when detecting a rising edge of a trigger pulse of a converter valve, latching the number of the converter valve; according to the trigger pulses of the converter valves, and amplitude characteristics of the AC currents and characteristics of AC variations, to perform a conducting state and a blocking state judgment of valve states, and obtaining valve states; judging whether each phase has a bypass state; through summing the valve bypass states of the three phases to judge a number of bypass phases; supplementing bypass loop voltage equation; calculating the converter valve currents; when the calculated value of th

Abstract: A short-circuiting device according includes a short circuit that is electrically connected to a robot, the robot including a robotic arm and at least one motor, the robotic arm including at least one joint shaft that is provided with the respective at least one motor, the short circuit being provided separately from a robot controller configured to control the robot, the short circuit being configured to apply a dynamic brake to each motor.

Abstract: The present disclosure relates to a fracturing system comprising a functional unit, an electricity supply unit and an energy storage unit. The functional unit is configured to perform procedures of fracturing operations. The electricity supply unit is electrically connected with the functional unit and is configured to supply electrical energy to the functional unit. The energy storage unit is respectively electrically connected with the electricity supply unit and the functional unit, and is configured to store electrical energy from the electricity supply unit and supply electrical energy to the functional unit.

Abstract: A system for printing a three-dimensional object is provided. The system can include at least one print head configured to receive a continuous fiber and at least partially encase the continuous fiber with a formation material to create a composite material. The at least one print bed can be configured to move in at least six different degrees of freedom. The system can also include at least one print bed comprising a printing surface onto which the composite material may be selectively applied to form a work piece. The at least one print head can be positioned relative to the at least one print bed and configured to advance print media thereon.

Abstract: The present disclosure relates to a fracturing system comprising a functional unit, an electricity supply unit and an energy storage unit. The functional unit is configured to perform procedures of fracturing operations. The electricity supply unit is electrically connected with the functional unit and is configured to supply electrical energy to the functional unit. The energy storage unit is respectively electrically connected with the electricity supply unit and the functional unit, and is configured to store electrical energy from the electricity supply unit and supply electrical energy to the functional unit.

Abstract: The present invention provides an electric power dispatching system and an electric power dispatching method. The electric power dispatching system has a plurality of accommodating spaces, a DC bus, an AC/DC power conversion device, and an energy control center. The swappable battery pack in each accommodating space is coupled to the DC bus, and the AC/DC power conversion device is coupled between the DC bus and a power grid. The electric power dispatching method includes centrally storing a plurality of swappable battery packs from different electric vehicles; and controlling the AC/DC power conversion device and each swappable battery pack located in each accommodating space by an energy control center to designate a part of the swappable battery packs located in the accommodating spaces to participate in a first power dispatch task so as to provide power dispatch to the power grid.

Abstract: A bipole power transmission scheme with two independent converts, two power feed and one return conduit. During operation of the bipole power transmission scheme under abnormal conditions, when a return conduit is faulty and unable to provide a return current path, each converter controller is programmed to monitor the first power feed in the first transmission conduit and the second power feed in the second transmission conduit and, if the first power feed in the first transmission conduit and the second power feed in the second transmission conduit differ from one another, at least one converter controller modifies the power infeed from its corresponding power source to reduce the difference between the first power feed and the second power feed.

Abstract: A modular electric power converter includes a plurality of power converter modules, each module comprising a cell of a Modular Multilevel Converter, MMC, to provide a controlled ac output.

Abstract: A voltage source converter (VSC) system of a high-voltage direct current (HVDC) system is disclosed. The system includes a number of line-commutated converter (LCC) transformers. Each LCC transformer is operable to transform alternate current (AC) voltage. A number of VSC converter units are connected in series and coupled to the plurality of LCC transformers. Each VSC converter unit is operable to convert between the AC voltage and direct current (DC) voltage. A bypass breaker is connected in parallel with at least one of the VSC converter units and operable to be closed to bypass the at least one VSC converter unit.

Abstract: A modular multilevel converter includes a plurality of submodules, each having at least two electronic switching elements, an electric energy store, two submodule connections, a bypass switch bridging the submodule, and a communication element communicating with a communication apparatus. A method for operating the modular multilevel converter includes ascertaining that the submodules have a defective submodule so that the communication element in the defective submodule does not communicate with the communication apparatus, determining whether a present arm current resulting from an operating point of the modular multilevel converter is below a predetermined threshold value, and generating or amplifying a converter-internal circular current with the defective submodule if the arm current resulting from the operating point is below the predetermined threshold value. A modular multilevel converter is also provided.

Abstract: A power conversion system applied to a solid state transformer includes a DC link, a plurality of capacitors, and a plurality of power conversion module assemblies. The plurality of capacitors is coupled in series between a positive bus and a negative bus of the DC link. Each of the power conversion module assemblies has a plurality of DC conversion modules. In any of the power conversion module assemblies, input sides of the DC conversion modules are connected in series to form two input ends of the power conversion module assembly, and output sides of the DC conversion modules are connected in parallel to form two output ends of the power conversion module assembly. Each of the plurality of power conversion module assemblies is correspondingly connected to each of the plurality of capacitors.

Abstract: An energy system substantially converts the power input into an AC power signal that is substantially synchronized with a power signal of the power grid. The energy system is further operable in alternative modes, including in an on-grid mode and off-grid mode. In the on-grid mode, the energy system provides the synchronized AC power signal to the power grid. In the off-grid mode, the energy delivers at least a portion of the AC power signal to a grid load.

Abstract: The present invention provides a high voltage direct current (HVDC) transmission system (300, 600) comprising: a first station (102) comprising series-connected first and second HVDC converters (110, 130); a second station (104) comprising series-connected third and fourth HVDC converters (150, 170), wherein a neutral node (164) coupling the third HVDC converter (150) to the fourth HVDC converter (170) is coupled to earth; a first transmission line (200) connecting a positive node (114) of the first HVDC converter (110) to a corresponding positive node (154) of the third HVDC converter (150), wherein a first pole (240) of the system (300, 600) comprises the first HVDC converter (110), the third HVDC converter (150) and the first transmission line (200); a second transmission line (210) connecting a negative node (138) of the second HVDC converter (130) to a corresponding negative node (178) of the fourth HVDC converter (170), wherein a second pole (250) of the system (300, 600) comprises the second HVDC conve

Abstract: The disclosure relates to a compact design method for inductive filtering transformer. According to the disclosure, the inductive filtering transformer adopts an approximative zero-impedance design under the premise of satisfying the filtering performance. The direct optimization objective is to minimize the distance from the transformer core center to the outermost winding. This disclosure balances the constraint of winding impedance matching and transformer size optimization and satisfies the application of limited installation space.

Abstract: The present invention concerns a node of an HVDC grid composed of HVDC nodes and of a plurality of links interconnecting the HVDC nodes, each HVDC node being interconnected to at least one HVDC node of the HVDC grid by a link composed of conductive cables for high voltage direct current transportation and one optical fiber, at least one HVDC node being interconnected to at least two HVDC nodes, each HVDC node comprising, for each link connecting the HVDC node to the at least one other HVDC node, a link module comprising a fault sensing device, a breaker, and an optical transceiver for communicating through the optical fiber of the link.

Abstract: Provided is a control method for a parallel MMC unit of a LCC-MMC hybrid cascade converter station. The control strategy includes: 1) numbering all MMC units connected in parallel in a MMC valve manifold; (2) for a MMC unit using a constant direct-current voltage control manner, calculating a direct-current instruction value of the MMC unit according to a direct-current measurement value; (3) for a MMC unit using a constant active power control manner, calculating an active power instruction value of the MMC unit according to the rated capacity of the MMC unit and a direct-current instruction value of a system rectifier station; (4) for the MMC unit using the constant direct-current voltage control manner, correcting a direct-current voltage instruction value of the MMC unit by using the direct-current instruction value and the direct-current measurement value, and controlling the MMC unit according to the corrected direct-current voltage instruction value.

Abstract: An electrical load system includes one or more electrical loads, a power transfer switch, and an electronic control system. The power transfer switch is coupled with and can provide power to one or more electrical loads from a first power source or a second power source. The electronic control system evaluates a source impedance of the first source and controls the power transfer switch in response to the source impedance of the first source indicating a fault condition of the first power source that would interrupt power from the first power source to the one or more electrical loads prior to the fault condition disrupting power from the first power source to the one or more electrical loads.

Abstract: Aspects are described for hybrid modular multilevel converters that include half-bridge submodules. In some embodiments, a hybrid modular multilevel converter can include a direct current (DC) bus and an alternating current (AC) node. A first arm of the hybrid modular multilevel converter includes a first submodule chain link and a first arm inductor and a second arm includes a second submodule chain link and a second arm inductor. A capacitor connects between a first side of the first arm and a first side of the second arm.

Abstract: The present disclosure provides a high-voltage interlock system and a detection method thereof. The high-voltage interlock system includes a target control device and at least one non-target control device connected in sequence. The target control device includes a detection unit, a current generation controller, a current generator, and a second high-voltage component. A controller in the target control device generates a pulse drive signal for driving the current generation controller, receives a detection result signal output from a current detector, and determines a fault of a high-voltage interlock circuit according to the detection result signal; the current generation controller generates an alternating voltage signal according to the pulse drive signal; the current generator outputs an alternating current signal according to the alternating voltage signal; the current detector acquires a voltage signal across a detection resistor set and outputs the detection result signal.

Abstract: Accordingly, the embodiments herein provide a hybrid modular multilevel converter. The hybrid modular multilevel converter includes one or more chain links, one or more high voltage switches and a plurality of inductors. The one or more chain links are formed by sub modules. The one or more high voltage switches are formed by semi-controlled devices or fully controlled or any other suitable semiconductor devices. The plurality of inductors are arranged in the one or more chain links to limit circulating current among the one or more chain links. The one or more chain links are configured to enhance a power handling capability of the hybrid modular multilevel converter.

Abstract: This invention relates to a method of controlling at least one wind turbine of a plurality of wind turbines connected to an electrical grid at a predefined point in the electrical grid. The wind turbine comprises a DC link connecting a generator side converter to a line side converter, where the line side converter is controlled according to a modulation index requested by a power converter controller. The method comprises determining a harmonic frequency signal indicative of a harmonic frequency value at the predefined point in the electrical grid; determining a deviation between the harmonic frequency signal and a permissible harmonic frequency value; determining a permissible modulation index based on the deviation; comparing the permissible modulation index to the modulation index requested by the power converter controller; and, altering a DC link voltage set-point based on the comparison between the permissible modulation index and the requested modulation index.

Abstract: A wind power converting device includes a plurality of grid-side converters, a plurality of generator-side converters and a plurality of DC buses. The grid-side converters are connected with each other in series and electrically coupled to a power grid. The generator-side converters are connected with each other in series and electrically coupled to a generator device. The DC buses are electrically coupled between the grid-side converters and the generator-side converters. The DC buses include a positive DC bus, a negative DC bus and at least one intermediate DC bus between the positive DC bus and the negative DC bus. A cross section area of a conductor of the intermediate DC bus is smaller than 30% of a cross section area of a conductor of the positive DC bus or smaller than 30% of a cross section area of a conductor of the negative DC bus.

Abstract: A transformer emulator includes a DC bus, a first power electronics converter circuit having a DC port coupled to the DC bus, a second power electronics converter circuit having a DC port coupled to the DC bus, and a third power electronics converter circuit having DC port coupled to the DC bus. The transformer emulator further includes a control circuit configured to control the first, second and third power electronics converter circuits to emulate a transformer having a first port corresponding to an AC port of the first power electronics converter circuit and a second port corresponding to an AC port of the second power electronics converter circuit. The control circuit is configured to control the first and second power electronics converter circuits to emulate a voltage transformation of the transformer and to control the third power electronics converter circuit to emulate a loss of the transformer.

Abstract: A system for supplementing the electric power needed by a pump jack electric motor, thereby reducing the electric power purchased from the local utility or power supplier. The system comprises a solar photovoltaic system, or other forms of renewable energy, and regenerated power from the electric motor or drive. The system can be both “on-grid” and “off-grid.” Battery banks and capacitor banks may be used to store energy.

Abstract: Systems and methods are configured to control DC side current harmonics of a cascaded H-bridge (CHB) converter that includes a plurality of cells. In various embodiments, an odd-order current harmonic is injected at the AC side of the CHB converter based on an optimization of a constrained optimization problem to achieve at least one of balancing the DC side current harmonics of the plurality of cells, reducing the DC side current harmonics of the plurality of cells, and meeting the requirements of the IEEE 519 standard. The optimization problem may include a cost function based on switching transitions of the CHB converter and at least one constraint based on, for example, an AC side current harmonic, a maximum demand load current of the CHB converter base on the IEEE 519 standard, and a zero-order current harmonic and an hth-order current harmonic for each cell of the CHB converter.

Abstract: A dynamic stability analysis and control method for a voltage sourced converter based high voltage direct current (VSC-HVDC) transmission system. The method includes the following steps: unlocking a converter station of the VSC-HVDC transmission system to make the VSC-HVDC transmission system run in a non-island control mode; extracting corresponding parameters of the VSC-HVDC transmission system, wherein the parameters include an effective voltage value Ut0 of an AC system, an outgoing reactive power Qvsc0 of the VSC-HVDC transmission system, a gain kp of a phase-locked loop (PLL), and a proportional integral time constant ki of the PLL; calculating a short-circuit ratio (SCR), an unit value of Ut0 and an unit value of Qvsc0; calculating a key stable component; checking the sign of the key stable component to determine the stability of the VSC-HVDC transmission system.

Abstract: A power system includes: a self-commutated power converter including a first arm and a second arm, each including switching elements; a first circuit breaker configured to interrupt a current flowing through a power transmission line provided between a first bus and a second bus; a first circuit breaker control unit configured to control the first circuit breaker; a converter control unit configured to stop the switching elements based on a first arm current value and a second arm current value; and a setting unit configured to set a voltage value of an AC voltage output from the power converter such that when a fault occurs in the power transmission line, the first circuit breaker is opened while the switching elements are not stopped. The converter control unit is configured to operate the switching elements such that an AC voltage with the set voltage value is output.

Abstract: The power conversion device includes multiple converter cells. Each converter cell includes a pair of primary-side terminals and a pair of secondary-side terminals. The converter cell transmits power between the pair of primary-side terminals and the pair of secondary-side terminals. The primary-side terminals of the multiple converter cells are connected in series to a primary-side power supply system. The secondary-side terminals of the multiple converter cells are connected in series to a secondary-side power supply system. Among the multiple converter cells, the converter cell in which an absolute value of a ground voltage appearing in the pair of primary-side terminals is the highest is different from the converter cell in which an absolute value of a ground voltage appearing in the pair of secondary-side terminals is the highest.

Abstract: Disclosed herein is a converter for converting an AC voltage to a DC voltage, the converter comprising: a first H-bridge circuit comprising a first AC terminal for receiving an AC voltage, a second AC terminal, a first DC terminal and a second DC terminal; a second H-bridge circuit comprising a first AC terminal for receiving an AC voltage, a second AC terminal, a first DC terminal and a second DC terminal; an isolation block arranged between the second AC terminal of the first H-bridge circuit and the second AC terminal of the second H-bridge circuit; and a DC voltage output of the converter with a first terminal and a second terminal; wherein: the first terminal of the DC voltage output is connected to the first DC terminal of the first H-bridge circuit and the first DC terminal of the second H-bridge circuit; and the second terminal of the DC voltage output is connected to the second DC terminal of the first H-bridge circuit and the second DC terminal of the second H-bridge circuit.

Abstract: An electrical device with a semiconductor circuit that is configured for a high voltage and is arranged in a housing. The housing is formed of a plurality of housing parts which are electrically insulated from one another. Different electrical potentials can be assigned to the housing parts. There is also described an converter with the electrical device.

Abstract: A methods and systems for generating rectified signals are disclosed. For example, a system performing the methods includes a current source rectifier which has a plurality of switches configured to receive an input current from an AC voltage source and to receive a plurality of control signals. The switches are configured to produce a rectified output current based on the input current and the control signals. The system also includes a rectifier controller configured to receive a current sense signal indicative of the rectified output current and to generate the control signals based at least in part on the current sense signal, where the control signals cause the current source rectifier to attenuate at least one of a plurality of harmonic frequencies in the rectified output current.

Abstract: A modular multilevel converter (MMC) includes multiple converter arms, each converter arm having: N submodules connected to each other in series, N being an integer equal to or greater than 2; and a circuit opening unit connected to the N submodules in series to open a circuit of the converter arm, wherein the N submodules has n submodules including full-bridge circuits and N?n submodules including half-bridge circuits, n being less than N.

Abstract: A balun includes first, second, and third terminals, first, second, and third inductors, and a capacitor. The first and second inductors are electrically connected in series with each other between the first terminal and a ground point. The capacitor is electrically connected in series with the first inductor between the first terminal and the ground point. The capacitor is electrically connected in parallel with the second inductor between the first inductor and the ground point. The third inductor is electrically connected between the second terminal and the third terminal. The third inductor is magnetically coupled with at least the first inductor.

Abstract: A stepless motor driving circuit provides a sinusoidal shaped chopping signal for driving a motor. The driving circuit has: a switch circuit having an input which receives a rectified signal rectified from a sinusoidal AC signal and having a first output and a second output where the motor is coupled between; a synchronizing signal generating circuit which generates a synchronizing signal relating to the sinusoidal AC signal; and a switch driving circuit which selects and chops at least one switch in the switch circuit according to the synchronizing signal, and to form the sinusoidal shaped chopping signal which is corresponding to the sinusoidal AC signal.

Abstract: A power conversion device which is connected between an electric generation grid and a demand area grid and performs power conversion includes: a power converter which is connected to an electric generation grid and which converts AC power received from the electric generation grid to DC power and transmits the DC power via DC bus; and a control device for controlling the power converter. The control device includes a detection unit for detecting DC current of the DC bus, and a protection control unit for performing protection control for suppressing an amount of power received from the electric generation grid, on the basis of variation in the DC current, thereby continuing operation in the case of disturbance in the demand area grid.

Abstract: The present disclosure relates to methods and devices for calculating winding currents at a delta side for a transformer. The transformer has two or more windings, with a first winding being a delta connected winding. The method includes obtaining line currents measured with measurement equipment associated with lines connected with the windings. The method further includes calculating zero sequence currents for at least a second winding, from the line currents of a corresponding line. The method further includes calculating zero sequence currents for the first winding, based on the zero sequence currents for at least the second winding, a phase displacement between the windings, and a turns ratio associated with the windings. The winding currents is calculated from the zero sequence currents of the first winding, and the line currents of a corresponding line.

Abstract: A wind turbine power generation system comprising a rotor shaft coupled to an electrical generator which generates a power output at a first AC voltage level; a converter system that converts the power output of the generator at the first AC voltage level to a converter power output at a second AC voltage level; a transformer that converts the converter system power output at the second AC voltage level to a generation system power output at a third AC voltage level; wherein the converter system comprises a machine-side converter, a line-side converter and a DC-link. The machine-side converter is a line-commutated rectifier, and the transformer is an online tap changer transformer. In another aspect, the invention resides in a wind power plant comprising at least one wind power generation system electrically coupled to a substation for onward transmission to a grid.

Abstract: A method for isolating faults in an electrical power system connected to a power grid includes dividing the electrical power system into a plurality of power modules each including a plurality of electrical power subsystems and a substation. Each of the electrical power subsystems defines a stator power path and a converter power path for providing power to the power grid and having a partial power transformer. The method also includes coupling each of the power modules to the power grid via a primary electrical line. Further, the method includes monitoring the electrical power system for faults. In response to detecting a fault in one of the power modules, the method includes isolating the fault to the power module experiencing the fault. In contrast, if the fault is detected in the primary electrical line or the power grid, the method includes tripping the electrical power system.

Abstract: A method for controlling a renewable energy power plant comprising a plurality of wind turbine generators, the method comprising: measuring a voltage level associated with a point of interconnection between a power transmission network and the power plant; calculating a reactive power exchange limit based upon the measured voltage level; and controlling the power plant so that the calculated reactive power exchange limit is not exceeded.

Abstract: An object of the present invention is to provide a highly efficient power supply device. A power supply device 1 according to the present invention includes a bidirectional DC-DC converter 3 and an insulated DC-DC converter 4. The bidirectional DC-DC converter 3 receives a main battery 5 and outputs a direct-current link voltage Vlink. The insulated DC-DC converter 4 receives the link voltage Vlink and supplies power to a load 7. The link voltage Vlink, which is an output of the bidirectional DC-DC converter 3, changes according to the output voltage of the insulated DC-DC converter 4.

Abstract: Controlling a wind turbine during a grid fault where the grid voltage drops below a nominal grid voltage. After detection of a grid fault, the total current limit for the power converter output is increased to a total maximum overload current limit. Depending on whether active or reactive current generation is prioritized, an active or reactive current reference is determined. The active current reference is determined in a way so that a reduction in active power production due to the grid voltage drop is minimized and based on the condition that the vector-sum of the active output current and the reactive output current is limited according to the total maximum overload current limit, and a maximum period of time is determined in which the power converter can be controlled based on the active/reactive current references. Afterwards the power converter is controlled based on the active and reactive current references.

Abstract: Methods and apparatus for protecting a direct-current (DC) electric power distribution system that includes one or more AC/DC converters and/or one more DC/DC converters, and one or more loads, connected by DC buses. An example method, which is carried out in response to the detection of a fault somewhere in the system, begins with limiting an output current of each of one or more of the converters so that each of the limited converters outputs a limited DC current at or about a corresponding predetermined current level. After the current limiting of the one or more converters has taken place, one or more protection devices in the system are activated, where the activating at least partly depends on the limited DC currents being at or about the predetermined fault current levels.

Abstract: A normalized-link-current estimation unit adopts a first value calculated by using a virtual DC voltage command, a phase and an amplitude of a single-phase AC voltage, and a distribution factor, as an estimated value of a value obtained by normalizing a link current flowing from a DC link to an inverter. A calculation unit determines a second value calculated by using the virtual DC voltage command, a rectified voltage, and a both-end voltage. When a normalized current command is less than a product of the first value and the second value, a normalized charge command is set to 0 and a rectifying duty is determined by dividing the normalized current command by the first value.

Abstract: A system includes a current source rectifier which has a plurality of switches configured to receive an input current from an AC voltage source and to receive a plurality of control signals. The switches are configured to produce a rectified output current based on the input current and the control signals. The system also includes a rectifier controller configured to receive a current sense signal indicative of the rectified output current and to generate the control signals based at least in part on the current sense signal, where the control signals cause the current source rectifier to attenuate at least one of a plurality of harmonic frequencies in the rectified output current.