Abstract: A multi-phase electric drive includes a multi-phase power transformer, including a primary winding and a first number of secondary windings, said primary winding being electrically connectable to a source of multi-phase AC power; a first number of power units, each of said first number of power units having input connected with a corresponding one of said first number of secondary windings, and a multiple of said first number of power units being serially connected with respective others of said power units in each phase output line connectable to a multi-phase AC load; at least one measurement device, being electrically connected with said input to at least one of said first number of power units and being adapted for measuring an electrical quantity at the input thereto; and a control system, being adapted for detecting a fault based on a value for the measured electrical quantity.

Abstract: Several defibrillators, defibrillator architectures, defibrillator components and methods of operating defibrillators are described. In one aspect, a defibrillator (as for example an automated external defibrillator) that can be powered by a mobile communication device such as a smart cellular phone or a tablet computer is described. Utilizing a phone (or other mobile communication device) as the power supply for an external defibrillator allows the external defibrillator to be smaller and, in some circumstance, removes the need for a battery that stores sufficient energy for shock delivery—which would need to be checked and/or replaced on a regular basis. Additionally, when desired, certain control functionality, computation, data processing, and user instructions can be handled/presented by the mobile communications device thereby further simplifying the defibrillator design and improving the user experience.

Abstract: This invention presents a family of isolated BESS topologies with multiple functions, which are suitable for high voltage and high power DC grid application. A battery energy storage system (BESS) for direct current (DC) grid applications is provided, including an alternating current (AC) transformer having a primary side and a secondary side, at least one primary side arm coupled to the primary side of the AC transformer, the at least one primary side arm comprising a plurality of cascade connected voltage source converter sub-modules and a plurality of energy storage battery units and at least one secondary side arm coupled between the secondary side of the AC transformer and a DC grid voltage bus, the at least one secondary side arm comprising a plurality of cascade connected voltage source converter sub-modules. Modulation and control strategies for the various topologies are also provided.

Abstract: A controller for controlling a multiphase brushless direct current (BLDC) motor is described. The controller may be configured to determine that the multiphase BLDC motor is operating in a phase delay state in response to determining that an indication of a shunt current for the multiphase BLDC motor satisfies a shunt current threshold and determine that the multiphase BLDC motor is operating in a phase advance state in response to determining that a set of phase-to-ground voltages for the multiphase BLDC motor does not indicate a zero-crossing point. The controller may further be configured to selectively energize each phase of the multiphase BLDC motor based on whether the multiphase BLDC motor is operating in the phase delay state or phase advance state.

Abstract: The invention provides a three phase medium voltage power conversion system for coupling a power source to a utility grid comprising a power converter and a Notch-Filter. The switching control system of the inverter of the power converter is based on SHE-PWM patrons. The Notch-Filter is tuned to attenuate the frequency of the first harmonic that the switching control system of the inverter cannot attenuate and configured with damping means capable of smoothing the resonance frequency without affecting the notch frequency.

Abstract: A control unit of an inverter for driving a three-phase motor receives a voltage of a connection point from a circuit, in which the connection point interconnecting one end of each of three first resistors is connected to the ground through a second resistor, and the other end of each of the three first resistors is connected to each phase. The control unit diagnoses whether the inverter has incurred a failure based on the voltage of the connection point, the voltage being detected when a first switch provided on a positive bus is turned off, a second switch provided in parallel with the first switch and in series with a third resistor is turned on, a third switch provided in series with a fourth resistor between the power source and the connection point is turned on, and the switching elements are turned on or off according to a predetermined pattern.

Abstract: A five-level inverter and its application circuit are provided. The five-level inverter is enabled to output multiple levels of voltage by controlling different conduction combinations of first, second, third, fourth, fifth, sixth, seventh, and eighth switch transistors, as well as a clamping capacitor. Two conduction combinations may be selected for outputting a positive voltage, with currents flowing through the clamping capacitor in opposite directions in the two conduction combinations. Therefore the voltage of the clamping capacitor can be balanced by controlling the two conduction combinations. Similarly, when outputting a negative voltage, the voltage of the clamping capacitor can be balanced by controlling other two conduction combinations. Therefore, a balance of power capacitor voltage can be achieved at full power and full modulation without adding an extra hardware circuit.

Abstract: A multilevel converter includes a first and a second converter block series-connected between two DC terminals and a chopper circuit between the blocks. Each block includes a number of valve arm strings, each including an upper and a lower valve arm and a number of converter cells. A midpoint between the upper and lower arm of a string of the first block is connected to a corresponding primary AC terminal and a midpoint between the upper and lower arm of a corresponding string of the second block is connected to a corresponding secondary AC terminal. The chopper circuit comprises a power dissipating element in parallel with a circuit breaker.

Abstract: A rotary electric machine control device for a rotary electric machine having winding sets with coils includes: an inverter for each winding set; a power source relay for each inverter; a terminal voltage detector detecting a terminal voltage of each coil; and a controller including an inverter controller, a relay controller and an abnormality determination unit. Each winding set and a corresponding inverter provides a system. When the rotary electric machine is driven using a normal system: the relay controller controls the power source relay to cut off power supply from a power source to the inverter in an abnormal system; the abnormality determination unit specifies a short-circuited location based on the terminal voltage in the abnormal system; and the inverter controller corrects a command value related to control of the inverter in the normal system according to a specified short-circuited location.

Abstract: The disclosed embodiment relates to a method of controlling a system including at least one inverter with six switches, which is linked to a battery, and supervised by a processor. The method implements a vector modulation, so that it is able to prevent the current linking the battery from passing through zero amperes by means of appropriate control logic. The disclosed embodiment also relates to a device for controlling an electronic component.

Abstract: A motor drive device includes: reverse converter that converts DC power from a forward converter into AC power; a DC link capacitor provided in a DC link; a first current detection part that detects current flowing between the forward converter and capacitor; a second current detection part that detects current flowing between the capacitor and reverse converter; a voltage detection part that detects a voltage of the capacitor; and a capacitance decline detection part that obtains a change value in electric charge of the capacitor from a n integrated value by integrated a predetermined time of a difference in current values detected by the current detection parts, obtains a capacitance value of the capacitor based on the obtained change amount in electric charge and change amount in voltage of the capacitor for the predetermined time, and detects a capacitance decline in the capacitor based on the obtained capacitance value.

Abstract: A method for power conversion includes coupling a first string to a second string via a first connecting node and a second connecting node to form at least one leg of a power converter. The first string is operatively coupled across a first bus and a second bus and comprises a first branch and a second branch coupled via a third connecting node. The first branch and the second branch include a plurality of controllable semiconductor switches. Furthermore, the second string comprises a first chain link and a second chain link coupled via an alternating current phase bus and includes a plurality of switching units. The first chain link and/or the second chain link are controlled to generate a negative voltage across at least one of the plurality of controllable semiconductor switches during a switch turn off process.

Abstract: During a single-phase three-wire output control process for causing a neutral point clamped inverter circuit to have a single-phase three-wire output, a power converter performs a potential control process for changing a potential of the O terminal to a positive or negative value to allow more power to be consumed from power stored in one of first and second capacitors with a higher voltage than from power stored in the other one of the first and second capacitors.

Abstract: A power converter includes a plurality of converters which are connected in parallel to a DC power supply in which an operating point is changed in accordance with an output current or an output voltage. The plurality of converters include maximum power point tracking units for performing maximum power point tracking calculations of the DC power supply. Results of the maximum power point tracking calculations of the plurality of converters are unified between the plurality of converters and the plurality of converters are controlled based on the unified calculation result.

Abstract: A power tool is configured to receive power from a power supply. The power tool may include a rectifier that may output a rectified signal to a DC power bus. A switching arrangement may operate to deliver electric power from the DC power bus to an electric motor. A switch path may be electrically coupled in parallel with the rectifier on the DC power bus. The switch path includes an auxiliary capacitor in series with a switch and a state of the switch controls a discharging path for the auxiliary capacitor. A switch control circuit may be configured to detect voltage associated with at least one of the AC power supply or the DC power bus and to control state of the switch in accordance with magnitude of the detected voltage.

Abstract: An arrangement, method and computer program product are provided for limiting circulating currents in a converter converting between AC and DC. The converter has a number of AC and DC terminals and includes a number of converter arms, where a first and a second converter arm are connected in parallel between a first DC terminal and a first AC terminal. Each converter arm includes a string of series-connected converter cells. The arrangement includes a control unit that obtains a current of the first converter arm and a current of the second converter arm, forms an average of the two converter arm currents, forms a first and a second voltage control signal based on the average and uses the first and second voltage control signal in the control of the voltage provided by the first and second converter arm.

Abstract: A capacitor unit includes a casing, a heat sink, a heat radiation sheet, and a notch. The casing accommodates the capacitors. The casing includes a positive electrode terminal block and a negative electrode terminal block. The heat sink is provided on the casing in a stacking direction. The heat radiation sheet is made of insulation material and is sandwiched in the stacking direction between the casing and the heat sink to cover the positive electrode terminal block and the negative electrode terminal block. The notch is provided in at least one of the casing and the heat radiation sheet between the negative electrode terminal block and the positive electrode terminal block. The notch passes through the at least one of the casing and the heat radiation sheet along a plain substantially perpendicular to the stacking direction to separate the negative electrode terminal block and the positive electrode terminal block.

Abstract: This power transmission device is connected between an AC wiring system connected to an AC power supply, and a DC power supply, and transmits power from the DC power supply to the AC wiring system. The power transmission device includes an AC power supply voltage signal generator, a power converter, a DC voltage conversion unit, a switching element, and a switch open/close signal generator. The switch open/close signal generator includes: a control signal generation unit to generate a control signal formed from a pulse signal; and a pulse width determination unit to receive the control signal and generate a delayed signal obtained by delaying rising of the control signal, and when the delayed signal becomes a value corresponding to a magnitude of voltage of the AC power supply voltage signal, cause the control signal to fall, thereby making the control signal into the switch open/close signal.

Abstract: The modulation methods for quasi-Z-source cascade multilevel inverters relate to control and signal modulation of quasi-Z-source cascade multilevel inverters, such as those used with photovoltaic power systems. The modulation methods for quasi-Z-source cascade multilevel inverters include a modular multilevel space vector modulation method for a photovoltaic quasi-Z-source cascade multilevel inverter for compensating for unequal voltages of separate photovoltaic modules, a pulse-width-amplitude modulation method for multilevel inverters for use in solar panel arrays attached to a three phase power grid, and a grid-connected control method for quasi-Z-source cascade multilevel inverter-based photovoltaic power generation for extracting maximum power from each Z-source cascade multilevel inverter.

Abstract: It is provided a multi-phase electric drive for use with a multi-phase AC load and the power unit thereof. The multi-phase electric drive includes a multi-phase power transformer with at least one primary winding and a plurality of secondary windings. The primary winding may be electrically connected to a source of multi-phase AC power. Power units may have an input connected with a corresponding one of said plurality of secondary windings and may have a single-phase controllable output to such multi-phase AC load. The power units may be serially connected with respective others of said power units in each phase output line and are connectable to said multi-phase AC load.

Abstract: A system and method for controlling power supply input filter oscillations is provided. The method includes utilizing a converter power circuit to generate a positive input resistance to counteract input filter oscillations, which are generated in response to normal converter negative input impedance and current-mode control operation. A controller controls the converter power circuit to generate the positive resistance utilizing a first input corresponding to the voltage applied to the converter input. A second input disables the converter power circuit based on completion of output capacitor charge, the first and second inputs being different.

Abstract: The conversion apparatus includes a conversion module having a plurality of phases, each having a converter capable of performing voltage conversion of discharging electric power of a power source and a sensor detecting phase current flowing in the converter, and in which the phases are electrically connected in parallel, and a controller which controls each converter with a control signal based on a predetermined duty ratio. The controller includes a first determination unit which determines a basic duty ratio common to all of the plurality of phases, a second determination unit which determines a correction duty ratio for correcting the basic duty ratio at each of the converters, and a generation unit which generates a control signal based on the basic duty ratio and the correction duty ratio. The second determination unit determines the correction duty ratio, and sets an upper or lower limit value of the correction duty ratio.

Abstract: A system and method are provided for enabling multi-functional support of an extant synchronous alternating current (AC) grid. At least one extant electricity source and at least one extant electricity sink are connected by two or more high-voltage direct current (HVDC) transmission circuits connected in turn in series with each other with at least one pair of HVDC circuits interconnected through an intervening high-voltage AC (HVAC) point of interconnection. One or more of the HVDC transmission circuits includes a 2-terminal or a multi-terminal transmission link. A 2-terminal HVDC circuit is dedicated to connecting with the electricity sources and sinks.

Abstract: A downhole paraffin melting tool is provided, comprising a heating element housing having a cutting head and a heating element disposed within the heating element housing. A battery pack is disposed within a battery pack housing, wherein the battery pack is operatively connected to the heating element. A control board is disposed between the heating element and the battery pack, wherein the control board is adapted to control power delivered from the battery pack to the heating element. A top sub is connected to the battery pack housing, wherein the top sub includes a retrievable member. The battery pack, delivering power to the heating element through the control board, is adapted to maintain a predetermined temperature of the heating element during operation.

Abstract: Embodiments herein disclose a hybrid multilevel inverter configured to obtain N-level output voltages based on operating one of FCs and a plurality of switches. In an embodiment, the multilevel inverter is a Neutral Point Clamped (NPC) Flying Capacitor (FC) based hybrid multilevel inverter. In an embodiment, the multilevel inverter is a stacked multi-cell NPC multilevel inverter.

Abstract: Unique systems, methods, techniques and apparatuses for a ZVT ZCT resonant converter with a variable resonant tank are disclosed. One exemplary embodiment is a system comprising a bidirectional resonant converter comprising an input/output terminal, a switching device coupled with the input/output terminal, a resonant circuit coupled with the switching device and including a variable inductor, an output/input terminal coupled with the resonant circuit, and a DC biasing circuit operatively coupled with the variable inductor. The variable inductor comprises a toroidal core, a first winding wound around the toroidal core and coupled with the switching device and the output/input terminal, a second core structured to overlap a portion of the toroidal core, and a second winding wound around the second core and coupled with the DC biasing circuit. The DC biasing circuit is controllable to vary the inductance of the variable inductor by saturating a portion of the toroidal core.

Abstract: A power conversion system can be implemented to reduce load disturbances on a DC bus which may be caused by load activity, such as a motor starting, stopping and/or ramping up or down. In one aspect, the power conversion system can receive externally supplied multi-phase AC electric power, such as three-phase power from a power grid, and use a converter circuit to generate the DC bus. The power conversion system can then use an inverter circuit to generate multi-phase AC electric power from the DC bus for driving the load with adjustable frequencies and/or amplitudes as desired. The power conversion system can receive feedback signals to sense the load activity and adjust the converter and/or inverter circuits accordingly to reduce the load disturbances on the DC bus.

Abstract: Disclosed examples include power conversion systems, computer readable mediums and methods for mitigating input filter resonance, in which a controller operates an active front end (AFE) rectifier in a first mode to turn a single rectifier switching device on and off and measures a filter voltage or current signal while all of the rectifier switches are off. The controller determines a resonant frequency based on a transient response of the measured voltage or current signal, and selectively adjusts a rectifier control parameter to mitigate filter resonance based on the resonant frequency.

Abstract: A hybrid switch apparatus includes a gate drive circuit producing a gate drive signal, a GaN high electron mobility transistor (HEMT) having a first gate, a first drain, and a first source. A silicon (Si) MOSFET has a second gate, a second drain, and a second source. The GaN HEMT and the Si MOSFET are connected in a parallel arrangement so that (i) the first drain and the second drain are electrically connected and (ii) the first source and the second source are electrically connected. The second gate is connected to the gate drive circuit output to receive the gate drive signal. A delay block has an input connected to the gate drive circuit output and an delay block output is configured to produce a delayed gate drive signal for driving the GaN HEMT.

Abstract: The present invention relates to a motor driving apparatus and a home appliance including the same. A motor driving apparatus according to an embodiment of the present invention includes an inverter for converting a DC voltage of a DC-link capacitor into an AC voltage according to a switching operation and outputting the converted AC voltage to a motor; a DC-link resistor disposed between the DC-link capacitor and the inverter; and a controller for controlling the inverter based on a phase current sampled through the DC-link resistor, wherein the controller estimates a phase current based on the phase current sampled through the DC link resistor, in an interval in which phase current detection is not possible. Thereby, the phase current flowing through the motor may be accurately calculated using the DC link resistor.

Abstract: A direct-current power supply device includes a reactor, one end of which is connected to one output end of an alternating-current power supply, a switching unit for short-circuiting the other end of the reactor and the other output end of the alternating-current power supply, a rectifying unit configured to rectify an alternating-current voltage supplied from the alternating-current power supply and generate a voltage equal to or higher than a double voltage, a smoothing capacitor connected to the rectifying unit via backflow preventing diodes and configured to smooth a direct-current voltage output from the rectifying unit, and a control unit configured to control the switching unit and stop the supply of the alternating-current voltage to the rectifying unit in a predetermined period after a predetermined time has elapsed from a zero cross point of the alternating-current voltage output from the alternating-current power supply.

Abstract: A UPS sensitivity of power status parameter adjustment setting method used in UPS system for allowing sensitivity setting of power status parameter manually by user or according to system default value. Microcontroller can automatically switch sensitivity to HIGH to enhance power protection if power status of input power supply is judged in the range set according to option of energy-saving, electrical safety or set time in priority after completing counting time. If power generator of relatively lower power quality level is used for input power supply, microcontroller can automatically switch sensitivity to LOW subject to option of energy-saving in priority and employ a low-sensitivity detection of power judgment, maintaining USP system in normal mode without being changed to battery mode, preventing system shutdown due to complete discharge of stored energy systems, and UPS system can operate normally, and power supply of stored energy systems can be prolonged and well-protected.

Abstract: A first reactor is provided on the input side of a rectifying circuit that rectifies AC power (on the side of an AC power supply), and on the output side of the rectifying circuit (on the side of a load), first and second capacitors that are connected in series to each other, and first and second switching elements that switch between charging and not charging of the first and second capacitors, respectively, are provided, a second capacitor group in Y-connection, provided with three capacitors, each of which is connected to each phase-terminal of the first reactor on the side of the rectifying circuit, is connected to the midpoint of the first and second switching elements, and the output voltage to the load is boosted, while the on-duty of the first switching element and the on-duty of the second switching element are controlled to be equal to each other.

Abstract: There are provided methods, devices, and systems relating to discharging thyristor-switched capacitors. For example, there is provided a method for discharging the capacitors of a thyristor-switched capacitor (TSC) device coupled to a transmission line. The method can include determining whether an angle of a voltage on the transmission line is within one of a first threshold range and a second threshold range. Further, the method can include discharging the capacitors, when the angle is within the first threshold range, by operating the TSC device in a first discharging mode. Furthermore, the method can include discharging the capacitors, when the angle is within the second threshold range, by operating the TSC device in a second discharging mode distinct from the first discharging mode.

Abstract: A circuit system having a voltage converter having an input path, an output path, and having a plurality of phases, each phase having at least one half-bridge and at least one fuse, each branch of the half-bridge having a respective MOSFET. The circuit system recognizes a defective MOSFET and controls the MOSFETs of the intact phases in such a way that a sufficiently large current trips the fuse connected in series with the defective MOSFET in order to enable an emergency operation of the voltage converter. A method for operating such a circuit system is also described.

Abstract: Invention is related to a method for controlling an alternating current electric machine with a frequency converter including a controllable machine bridge and a controllable line bridge, and a corresponding frequency converter. The method comprises calculating a line bridge control signal, controlling line current through the line bridge using the line bridge control signal, measuring or estimating rotor pole position of the electric machine, calculating a machine bridge control signal as a function of the rotor pole position, updating the machine bridge control signal when the rotor pole position changes, and controlling current of the electric machine through the machine bridge using the machine bridge control signal.

Abstract: The present disclosure relates to power management systems utilizing a high-frequency low voltage pre-charge. A power management system may comprise a low voltage power source, a power supply assembly connected to the low voltage power source, and a power module comprising a plurality of arrays. Each array may comprise a plurality of electrically isolated stacks connected through a synchronous common coupling. Each electrically isolated stack may comprise a plurality of stages, a multi-winding secondary, a pre-charge circuit connected to at least one of the plurality of stages, and a plurality of multi-winding isolated power supplies. Each multi-winding isolated power supply may be connected to one of the plurality of stages. The power supply assembly may be configured to supply charging current from the low voltage power source to at least one of the plurality of electrically isolated stacks.

Abstract: A paralleled drive having a first plurality of interphase inductors to distribute three phase alternating current power to a first and a second converter that transfer power to a first and a second direct current (DC) buses respectively, a bus coupler connecting the first and second DC buses, a first and a second inverter connected to the first and second DC buses respectively. The drive also includes a controller connected to the first and second converters and the first and second inverters, the controller generates control signals to cause the first and second converter to transfer power to the first and second direct current (DC) buses respectively, and the controller configured to generate control signals to cause the first and the second inverters to generate a plurality of motor excitation signals respectively, and a second plurality of interphase inductors operable to combine the plurality of motor excitation signals.

Abstract: A main circuit of a power conversion device includes: an AC/DC converter for performing power factor correction control for a single-phase AC power supply; and a DC/DC converter connected to the AC/DC converter via a DC capacitor. In order to reduce ripple voltage and ripple current for the DC capacitor, a control circuit superimposes, onto a DC current command, an AC current command having the minimum value at the zero cross phase of the single-phase AC power supply and having the maximum value at the peak phase thereof, to generate an output current command for the DC/DC converter, and performs output control for the DC/DC converter, using the output current command.

Abstract: An electric railcar power feeding system in an embodiment includes a power storage device, a rectifier, and an emergency power supply. The power storage device is connected to a feeder line for an electric railcar. The rectifier converts alternating-current power of a first power system to direct-current power and supply the direct-current power for the feeder line. The emergency power supply supplies power of a second power system different from the first power system for the feeder line.

Abstract: A method is provided for operating a multi-cell power supply that includes multiple series-connected power cells in each of multiple legs. Each power cell includes a bypass device that may be used to selectively bypass and de-bypass the power cell. After a first power cell faults and is bypassed as a result of the fault, the method includes de-bypassing the first power cell without stopping the multi-cell power supply if the first power cell fault was caused by a predetermined operating condition. Numerous other aspects are provided.

Abstract: There are provided methods, devices, and systems relating to discharging thyristor-switched capacitors. For example, there is provided a method for discharging the capacitors of a thyristor-switched capacitor (TSC) device coupled to a transmission line. The method includes determining whether an angle of a voltage on the transmission line is within a threshold angle. Further, the method can include operating the device in a discharging mode when the angle is within the threshold angle and the threshold angle is in a predetermined set of threshold angles.

Abstract: An electric power transmission device contactlessly transmits electric power to an electric power receiving device. The electric power transmission device includes an inverter, a power transmission unit and an electronic control unit. The electronic control unit is configured to determine whether a current phase of output current flowing from the inverter to the power transmission unit leads output voltage, and adjust a frequency of the AC power in a direction to reduce a lead angle of the current phase when leading of the current phase relative to the output voltage is detected.

Abstract: A power conversion apparatus includes: a power converter that includes a plurality of switching elements; a switch controller that controls the plurality of switching elements so that the order of outputting a plurality of kinds of voltage vectors from the power converter is opposite in a first half and a latter half of a carrier period; a DC-side current detector that detects a DC-side current of the power converter; and a phase current detector that detects one phase current among three phase currents on the basis of the detected DC-side current at a detection timing, the detection timing being selected from a first-half timing and a latter-half timing of the carrier period at which the same kind of voltage vector is output. The phase current detector includes a timing switcher that alternately switches the detection timing between the first-half timing and the latter-half timing.

Abstract: A discharge duty that is a duty at which a switch is conductive takes a value obtained by dividing a product of a crest value of a single-phase AC voltage and a square of a cosine value of a phase of the single-phase AC voltage by a both-end voltage across a capacitor. A sum of a product of a rectifying duty that is a duty at which a converter is conductive and a rectified voltage output from the converter and a product of the both-end voltage and the discharge duty varies in a period that is a half of the period of the single-phase AC voltage.

Abstract: Plural electric power supplies are connected in parallel to an output bus. The plural supplies include a primary power supply and a redundant switching power supply. The primary power supply is configured to provide output current to a load when the primary power supply is operating normally. The redundant supply is configured to remain online while not providing output current to the load when the primary power supply is operating normally, but to begin providing output current to the load when the primary power supply is not operating normally.

Abstract: A power converting apparatus outputs an alternating-current power to drive an electric motor, and includes: a switching circuit that converts an input direct-current power to an alternating-current power based on driving of MOS-FETs and outputs the alternating-current power; and a driving control unit capable of controlling a carrier frequency and controlling the driving of the MOS-FETs. The driving control unit controls the carrier frequency on the basis of a noise level of a carrier noise obtained by combining noises that occur in the electric motor and the power converting apparatus due to the driving of the MOS-FETs at the carrier frequency and a noise level of driving noises from a plurality of noise sources that occur irrespective of the carrier frequency in the same housing in which the power converting apparatus and the electric motor are contained.

Abstract: A power system having a plurality of power converters coupled together at a point of common coupling (PCC). The power converters are coupled to a load and provide a combined power converter output to the load. A switch is coupled in series between the PCC and an external grid. When the switch is closed, the power system is in a grid-tied configuration and when the switch is open, the power system is in a microgrid configuration. A control system coupled to the power converters enables the switch to open and close in response to a signal received from one or more sensors monitoring the external grid, enables the power converters to operate in a current control mode when the switch is closed, and transitions the power converters from grid-tied mode to microgrid mode and synchronize the power converters such that the converters share the load.

Abstract: Reduction in size and weight of transformer for grid tie applications is demanded and can be achieved by applying SST to the transformer. However, SST application to PCS for sunlight requires the following: handle a wide variation range of the voltage of solar power generation; reduce switching losses of power devices, DC/DC converter and inverter, in the power circuit to implement high frequency for SST application; increase voltage to the grid voltage; and reduce the dimensions of the high current path prior to step-up. Thus, LLC resonant converter configuration is applied with an inverter placed in the output, and series connected configuration is applied to the inverter. The LLC resonant converter is subject to constant frequency regulation with large output, step-up control with low output, and step-down control with the upper limit voltage according to MPPT voltage from sunlight, in order to achieve drive loss reduction and voltage range handling.

Abstract: A method for operating an inverter with reactive power capability that includes a voltage link circuit and an unfolding bridge, wherein poles of the voltage link circuit are configured to be selectively connected to terminals of an AC output in different configurations by means of the unfolding bridge, in order to change a polarity of the AC output relative to the voltage link circuit. The method includes in the case of a phase shift between an AC current (I) and an AC voltage (U) at the AC output reversing the direction of a current flowing via the voltage link circuit.