Abstract: In a power converter, at least two main current paths each including an inductor and a transistor are connected between input terminals, and at least two storage circuits each including capacitors are correspondingly connected to branch nodes of the main current paths. Diodes are connected between the storage circuits. The transistors of the main current paths are interleaved. When one of the transistors is turned off, a current flowing in the corresponding inductor flows into the corresponding storage circuit to turn on the diodes and to charge the capacitors of the corresponding storage circuit. When another one of the transistors is turned off, a current flowing in the corresponding inductor flows into the corresponding storage circuit to turn on the diodes and charge the capacitors of the corresponding storage circuit.

Abstract: A power converter control system includes a first power converter, at least one additional power converter, a first control module, and an additional control module. The first power converter receives direct current and outputs alternating current as a first power output. The additional power converter receives direct current and outputs alternating current as an additional power output. The first control module controls timing of events of the first power converter. The additional control module is associated with the additional power converter and controls timing of events of the additional power converter. The first control module communicates first information regarding the timing of the first power converter to the additional control module. The additional control module is configured to adjust the timing of the additional power converter to correspond with the timing of the first power converter.

Abstract: An embodiment multilevel inverter comprises a first boost apparatus having an input coupled to a positive dc bus and a second boost apparatus having an input coupled to a negative dc bus. The multilevel inverter further comprise a first switch coupled to an input of an L-C filter and the first boost apparatus, a second switch coupled to the input of the L-C filter and the second boost apparatus, a third switch coupled between the positive dc bus and the first switch and a fourth switch coupled between the negative dc bus and the second switch.

Abstract: The invention relates to a process of connecting an AC output of a transformerless inverter of a solar power plant to an internal AC power grid at an input side of a galvanic isolation, while an offset voltage for shifting a potential center point of a photovoltaic generator connected to the inverter is applied. The process includes: (i) synchronizing the inverter with the power grid; (ii) essentially matching a potential center point of the current-carrying lines of the AC output and a potential center point of the power grid, while only one of the potential center points of the current-carrying lines and the power grid is yet shifted by the offset voltage; and (iii) galvanically connecting all current-carrying lines of the AC output with the power grid only after the steps of synchronizing and essentially matching.

Abstract: The invention discloses an electric leakage warning and protection circuit which includes a zero-sequence transformer, a overcurrent sensor and a zero line electricity leakage sensor are sequentially arranged and connected with a first control module, the first control module is further connected with a control end of a first silicon controlled rectifier, the first silicon controlled rectifier and a tripping coil are serially connected with each other and are jointly arranged between an anode and a cathode of the power module, an electric leakage display circuit is provided with a second silicon controlled rectifier and a first light emitting diode, the second silicon controlled rectifier is serially connected with the first light emitting diode, and a control end of the second silicon controlled rectifier is connected with the second control module.

Abstract: A system and method for proportioned power distribution in arrays of power converters are disclosed. According to one embodiment, a method includes distributing a node-specific transfer function to each node of a plurality of nodes via a communication bus. Each node includes a power converter, and nodes of the plurality of nodes are electrically connected in series. Each node-specific transfer function enables each node to contribute a positive impedance to a total impedance of the plurality of nodes. The computer-implemented method further includes coordinating a setting of a parameter of each node-specific transfer function to regulate a common bus current across the plurality of nodes, and assigning to each node an electrical characteristic based on a parameter of each node-specific transfer function.

Abstract: A converter circuit with short-circuit protection can include a plurality of phase legs having a series connection of normally-on switches, between voltage rails of a DC voltage link, a DC link capacitor, and AC voltage connection points between the normally-on switches. A phase-to-phase short-circuit protection circuit includes a parallel connection of a resistive component and a controllable switch. The phase-to-phase short-circuit protection circuit including a first terminal connected to an AC voltage connection point and a second terminal forms an input or an output of the converter circuit; and a controllable switch is connected in series with the DC link capacitor. Upon lack of control of the normally-on switches the controllable switch of the at least one phase-to-phase short-circuit protection circuit and the controllable switch of the phase leg short-circuit protection circuit are adapted to be controlled to a non-conductive state.

Abstract: Pipes of a weldable polymer material are welded with a muff of a weldable polymer material. The method includes placing the muff with an overlap over the ends of the pipes, welding the muff to the ends of the pipes through placement of an electrically conducting band that is permeable to molten plastic between the pipe and the muff, connecting a power supply to the band through feed cables, and supplying an electrical current in order to heat the band and the surrounding polymer material such that they melt together around the band in order to form a weld. The temperature of the weld is calculated through adding the initial ambient temperature of the weld and the increase in temperature of the band.

Abstract: A method of operating an inverter device configured on a back plane of a solar module, the inverter device comprising an energy recovery circuit device coupled to a rectifier circuit, the method comprising transferring a charge from a rectifier output to a storage capacitor configured in an energy recovery circuit; storing the charge at the storage capacitor for a time period associated with a reverse recovery time; and transferring the charge to an output of a DC bus structure to reduce a diode recovery loss in the rectifier circuit.

Abstract: A power conversion device includes: an inverter that includes high potential side switching elements connected to a high potential side and low potential side switching elements connected to a low potential side, and converts a current for supplying a rotating electric machine; a current detector having a sensor disposed on at least one of a positive bus for connecting the high potential side switching elements and a positive side of a DC power supply or a negative bus for connecting the low potential side switching elements and a negative side of the DC power supply; an energization device that energizes the sensor without passing through the inverter; and a controller that acquires a current detection value from the current detector, and controls the inverter and the energization device. The energization device energizes the sensor when all of high or low potential side switching elements are off.

Abstract: A modular multilevel converter system. The system includes a plurality of series connected two-terminal M2LC cells arranged into at least two output phase modules. A first one of the output phase modules has an inductance and an effective capacitance associated therewith. The first one of the output phase modules is configured so that a natural resonant frequency of the inductance with the effective capacitance of the first one of the output phase modules is greater than at least one of the following: an operating frequency of the first one of the output phase modules; a switching frequency of the first one of the output phase modules; and a switching frequency of any of the M2LC cells of the first one of the output phase modules.

Abstract: To solve problems arising when a power conditioner equivalent to that connected to a solar panel is connected to a power storage device. Direct-current power generated by the solar panel 9 is supplied to a DC-DC converter 51 and output as a predetermined direct-current voltage. The output voltage of the converter 51 is supplied to a DC-AC inverter 52. Direct-current power generated by the power storage device 11 is supplied to a DC-DC converter 55. Predetermined direct-current power from the converter 55 is supplied to a DC-AC inverter 56. Alternating-current power output by the inverter 56 is supplied to an alternating-current power system at home. The converter 55 is configured to have two output voltages. The first output voltage is a standby voltage. The second voltage is a voltage at which the inverter 56 starts power supply to outside.

Abstract: The present invention relates to a driving method for a modular multi-level converter. The driving method include inputting a current reference value (i*pj2) of the upper valve of the modular multi-level converter, measuring a current value (ipj2) of the valve, calculating an error value (errpj2) between the current reference value and the measured current value of the upper valve, measuring a DC link voltage value (Vdc2) of the modular multi-level converter, measuring a AC-grid voltage value (Esj) of the modular multi-level converter, and calculating a voltage reference value (u*pj2) using the current reference value (i*pj2), the measured current value (ipj2), the error value (errpj2), the DC link voltage value (Vdc2), and the AC-grid voltage value (Esj).

Abstract: A wireless power distribution and control system may be used to supply power wirelessly to various devices. The devices in the system may have control over the system and/or over certain features of other devices. For example, a smartphone charging in the wireless power distribution and control system may have access to and control over other devices in the system, such as the overhead lights, or a projector in a conference room. The identification of other devices, as well as commands for controlling these devices may be communicated over the wireless power link. The type and degree of control of each device in that system may vary based on access control levels for the power supplies and connected devices. The devices that receive power may be configured to automatically connect with the power distribution system and to monitor the other devices connected to the system.

Abstract: A converter, for use in high voltage direct and alternating current power transmission comprises a primary charge transfer converter. The charge transfer converter includes first and second primary terminals for connection to one or more electrical networks. The primary charge transfer converter also includes a plurality of charge transfer elements and a plurality of primary switching elements which are connected in a cascade circuit between the first and second primary terminals. Each charge transfer element includes at least one resonant circuit. The primary switching elements are operable to selectively cause charging and discharging of each resonant circuit to transfer charge between the charge transfer elements and thereby create a voltage difference between the first and second primary terminals.

Abstract: A method for pre-charging a motor drive system includes: pre-charging a motor drive through a motor DC bus where desired, pre-charging an add-on capacitive module through a resistor after a time delay, pre-charging the add-on capacitive module and bypassing the resistor, and disconnecting the add-on capacitive module from the motor DC bus when a fault condition has been detected.

Abstract: The method is for making a brushless direct-current (DC) motor quieter. A predetermined high frequency pulse width modulated (PWM) signal is generated. The PWM signal is sent to a first filter. The first filter truncates the PWM signal to provide the PWM signal with a rise time. The rise time allows transistors connected thereto to open smoothly. A second filter is provided that has a non-polarized capacitor. In a coil switching process, the non-polarized capacitor operates as a voltage or current absorption circuit between driving transistors. The coil switching process creates transient energy of voltage transients. The non-polarized capacitor absorbs the transient energy.

Abstract: The invention relates to an asynchronous motor unit including a frequency converter for regulating the asynchronous motor. The frequency converter comprises an input-side, uncontrolled bridge rectifier, a DC voltage intermediate circuit and an output-side inverter. According to the invention, the DC voltage intermediate circuit furthermore comprises a DC-to-DC converter with galvanic isolation, with the result that electrical isolation between the bridge rectifier and the inverter is produced.

Abstract: A system for operating a power generation system within a battery storage/discharge mode includes a power convertor having a DC link, a switching module coupled to the DC link, a storage device, and a filter coupled between the storage device and power converter. The filter may correspond to a normal mode filter configured to limit normal mode voltage from being applied to the storage device. A common mode filter may be associated with the storage device. The storage device may correspond to one or more batteries while the power generation system may correspond to a wind-driven generator.

Abstract: A multi-level inverter includes: a rectifying unit to rectify received a three-phase voltage; a smoothing unit to receive the rectified voltage and provide the rectified voltage as voltages having different levels to first to third different nodes; and an inverter unit including a plurality of switch units to transfer the voltages having three levels provided from the smoothing unit, wherein the inverter unit includes a first switch unit provided between the first node and a first output terminal, a second switch unit provided between the second node and the first output terminal, a third switch unit provided between the third node and the first output terminal, a fourth switch unit provided between the first node and a second output terminal, a fifth switch unit provided between the second node and the second output terminal, and a sixth switch unit provided between the third node and the second output terminal.

Abstract: A power converter module including a voltage source current controlled power converter for providing unidirectional current having at least four output voltage levels is provided. The voltage source current controlled power converter includes an input terminal and an output terminal, and a first conductive path and a second conductive path is coupled in parallel to each other between the input terminal and the output terminal. Each of the conductive paths comprises at least one diode and at least one switch coupled in series to the respective conductive path. The at least one diode in the first conductive path are coupled closer to the input terminal and the at least one diode in the second conductive path are coupled closer to the output terminal. The voltage source current controlled power converter further includes at least two energy storage elements coupled between the first conductive path and the second conductive path.

Abstract: A control method is disclosed that involves controlling zero-crossing operation of bridge arms in a UPS, wherein the UPS has a rectifying bridge with first and second switching transistors, a midline bridge arm with third and fourth switching transitors, and an inverter bridge arm with fifth and sixth switching transitors. The midline and rectifying bridge arms are controlled to cross zero synchronously. The inverter bridge arm is controlled to be disconnected during a period before a zero-crossing point of the rectifying bridge arm to a period after the zero-crossing point of the rectifying bridge arm. The periods before and after the zero-crossing point of the rectifying bridge arm are time differences between the zero-crossing points of the inverter bridge arm and the rectifying bridge arm. The influence of asynchronous zero-crossing between the PFC circuit and the inverter circuit on the UPS performance indices may be reduced by using the present control method.

Abstract: A solid-state switch includes a plurality of transistors connected in parallel and a plurality of fuses. Each fuse is connected in series with a separate one of the plurality of transistors. A combination of current ratings of the plurality of fuses is greater than a load current of a load connected to the plurality of transistors and the plurality of fuses, and a current rating of each separate fuse of the plurality of fuses is less than the load current.

Abstract: Split phase power conversion apparatuses, methods and systems are disclosed. One exemplary embodiment includes a generator, an AC/DC converter coupled with the generator, a DC bus coupled with the AC/DC converter, and an inverter coupled with the DC bus. The inverter includes first, second, and third legs each including a plurality of switches. A first controller provides a control signal to the first leg based upon a voltage between a first system output and a second system output and a first current provided to the first system output. A second controller provides a second control signal to the second leg based upon a voltage between the second system output and a third system output and a second current provided to the third system output. A third controller controls the third leg to provide an output equal to one half of the DC bus voltage.

Abstract: Disclosed herein are bi-directional DC converter circuits and control methods. In one embodiment, a method of controlling a bi-directional DC converter, can include: (i) detecting whether there is an input power supply at an input port, where the bi-directional DC converter comprises a single magnetic element; (ii) operating the bi-directional DC converter in a first operation mode to charge a battery when the input power supply is detected at the input port; (iii) operating the bi-directional DC converter in a second operation mode to transfer power from the battery to an output port for a load when the input power supply is not detected at the input port; and (iv) transferring power through the single magnetic element in both the first operation mode and the second operation mode.

Abstract: A power semiconductor module includes an element pair formed by connecting, in anti-parallel to each other, an IGBT and an FWD group in which an FWD, a voltage drop characteristic of which during conduction has a negative temperature coefficient, and an FED, a voltage drop characteristic of which during conduction has a positive temperature coefficient, are connected in series and an element pair formed by connecting, in anti-parallel to each other, an IGBT and an FWD group in which a FWD, a voltage drop characteristic of which during conduction has a negative temperature coefficient, and an FWD, a voltage drop characteristic of which during conduction has a positive temperature coefficient, are connected in series. The element pairs are connected in parallel.

Abstract: A multi-level medium-voltage inverter that receives three-phase power and outputs a three-phase voltage to a three-phase motor, includes: a plurality of unit power cells connected in series to output a single phase voltage, individual unit power cells each having a phase voltage forming a single level to configure multiple levels; and a module-type phase shift transformer configured to convert the three-phase power and applying the converted power to three unit power cells constituting one level, wherein the module-type phase shift transformer includes a plurality of modules.

Abstract: A method of controlling an inverter for converting a DC input to an AC output, the method including measuring a voltage of an AC output produced by the inverter; determining a drive voltage for controlling the inverter; and if a difference in amplitude and/or phase between the drive voltage and the measured voltage exceeds a predetermined threshold, modifying the drive voltage to reduce the difference in amplitude and/or phase between the drive voltage and the measured voltage. The method may be particularly useful for controlling an inverter during “islanded” operation with a variable load, and may therefore be useful e.g. in marine, battlefield, disaster relief and/or aviation electrical power systems.

Abstract: A power converter includes a rectifier section, an inverter section, a capacitance element connected between inverter section input ends, an inductance element forming part of an LC filter with the capacitance element, a voltage detector detecting an inductance element voltage, and a controller controlling the inverter section based on the detected voltage. The LC filter has a resonance frequency set such that ripple current components contained in DC current outputted from the rectifier section passes through, and current components of a frequency equal to a carrier frequency of the inverter section are dampened. The controller controls the inverter section so that a transfer characteristic of input voltage of the inverter section versus the DC voltage from the rectifier section becomes a damping characteristic given by a phase lead element and a second-order lag element connected in series, and a damping coefficient of the transfer characteristic is set larger than 1.

Abstract: Multilevel inverters, power cells and bypass methods are presented in which a power cell switching circuit is selectively disconnected from the power cell output, and a bypass which is closed to connect first and second cell output terminals to selectively bypass a power stage of a multilevel inverter, with an optional AC input switch to selectively disconnect the AC input from the power cell switching circuit during bypass.

Abstract: Disclosed herein is a control system, including: a first apparatus configured to adjust an output voltage thereof so that the output voltage may be included in a range determined in advance in response to a variation of an input voltage thereto from an electric power generation section; and a second apparatus configured to change a charge rate into a battery in response to the variation of the input voltage supplied from the first apparatus, wherein when a state in which the output voltage from the first apparatus is near to a lower limit thereof continues for a period longer than a period of time set in advance, one of two or more lower limits prepared in advance is selected as the value of the lower limit in accordance with to which one of sections set in advance input current from the electric power generation section belongs.

Abstract: A method for determining phase angle in phase shift transformer for medium voltage inverter is disclosed, the method including selecting an arbitrary phase shift angle and phase angle relative to a unit power cell of the first stage, determining a phase angle displacement in consideration of the phase shift angle and the number of unit power cells connected to each phase of a motor, determining a phase angle of the unit power cell at the second stage using a phase angle of the unit power cell at the first stage, and adjusting a phase angle when the determined phase angle of the unit power cell at the second stage exceeds a predetermined phase angle.

Abstract: A three phase full resonant cyclo-converter suitable for converting a three phase AC supply to a DC output. In one embodiment the cyclo-converter consists of two half bridge cyclo-converters driving a resonant circuit. The main switching sequence of the cyclo-converter may consist of a switching sequence in which the phases of a three phase supply are switched in a repeating sequence from the largest to the smallest absolute voltage value of the supply phases.

Abstract: There is provided a secondary battery system which converts direct current power supplied from secondary batteries into alternating current power by power converters, and supplies the converted power to an electric power system on a load side, the secondary battery system including a control apparatus that stops operating the operating the power converter and starts operating the stopped the power converter when a residual stored power level of the secondary battery corresponding to operating the power converter becomes to be not greater than a predetermined rate of a residual stored power level of the secondary battery corresponding to stopped the power converter.

Abstract: This invention belongs into the field of power electronics and semiconductor converter control and pertains to the method of shoot-through generation for modified sine wave Z-source, quasi-Z-source and trans-Z-source inverters. The inverter can be controlled using either the modified sine wave pulse-width modulation or phase-shift modulation method. There are three methods for shoot-through generation in the case of modified sine wave control: by overlapping active states, during the freewheeling state and during the zero state. To equalize switching losses in the case of unsymmetrical switching patterns, control signals of upper and lower switching elements are periodically interchanged.

Abstract: Electric power conversion device has first and second operation modes. First operation mode is of converting DC power from a first terminal into DC power having a desired voltage to be output to second terminal. Second operation mode is of converting DC power from the second terminal into DC power having a desired voltage to be output to first terminal. Switching section is configured to, in first operation mode, be turned on to cause short-circuiting between both ends of capacitor of rectifying circuit, and, in second operation mode, be turned off. First conversion part is configured to, in first operation mode, supply DC power-from first terminal, from first winding to second conversion part through a conversion circuit, and, in second operation mode, output to first terminal a voltage obtained by adding an output voltage of rectifying circuit to an output voltage of conversion circuit.

Abstract: A pre-charging system for a capacitor in a voltage inverter for an electric motor is provided. The system includes a grounding contactor electrically coupled between a grounding terminal of a battery pack and a first end of the capacitor. The system further includes a pre-charging contactor and a resistor electrically coupled in series. The pre-charging contactor and the resistor are electrically coupled between a high voltage terminal of the battery pack and a second end of the capacitor. The microprocessor determines a total amount of energy supplied to the resistor and induces the pre-charging contactor to have an open operational position to electrically de-couple the high voltage terminal from the second end of the capacitor, if the total amount of energy is greater than a threshold amount of energy.

Abstract: A method for limiting an output power of an inverter having an output bridge and an upstream boost converter includes determining a first measurement variable representative of a bridge temperature and a second measurement variable representative of an output power of the inverter. The method also includes determining a third measurement variable representative of a generator voltage at generator connections of the inverter or a fourth measurement variable representative of an output voltage at a power output of the inverter, and reducing the output power supplied to a power supply grid to a reduced power value. The reduced power value is determined based on the first measurement variable, the second measurement variable and at least one of the third and fourth measurement variables. A control device having such functionality is also disclosed.

Abstract: An UPS system and a method of supplying power to a non-linear load are provided. The UPS system may include a bypass module configured to supply a fundamental wave current to a non-linear load of the UPS system; and a power module configured to supply a harmonic current to the non-linear load when the bypass module operates normally.

Abstract: In one embodiment, an apparatus includes a first supply voltage and a second supply voltage. Level shifter circuitry is configured as a first voltage battery to shift a first voltage and a second voltage battery to shift a second voltage. A first circuit receives the shifted first voltage and sets a third voltage, and receives the shifted second voltage and sets a fourth voltage. The shifted first voltage is greater than the first supply voltage and the shifted second voltage level is less than the second supply voltage. A second circuit sets a fifth voltage and a sixth voltage. The fifth voltage follows the third voltage and the sixth voltage following the fourth voltage.

Abstract: A non-contact power receiving apparatus includes a power reception coil receiving, by electromagnetic resonance, the electric power transmitted from a power transmission coil; a rectifier rectifying the electric power received by the power reception coil, a load receiving the electric power rectified by the rectifier; a resistance and a connection switch provided in a pair of power lines for transmitting the electric power from the power reception coil through the rectifier to the load, the resistance and the connection switch being connected in series between the pair of power lines; and a control device. The control device renders the connection switch conductive when determining where the power reception coil is positioned, and renders the connection switch nonconductive when the electric power is transmitted to the load from the power reception coil through the rectifier.

Abstract: Multi-level rectifiers are provided. A multi-level rectifier may convert a medium AC voltage to a medium DC voltage. A multi-level rectifier may comprise an input inductor, a set of diodes, a set of switches, and a DC link comprising a set of capacitors. One end of the input inductor is coupled to the input AC voltage and the other end of the input inductor is coupled to a pair of diodes that are series connected. The set of switches may be regulated such that the inductor may be coupled to a DC voltage point of the DC link. A multi-level rectifier may operate under a set of operation modes. Each operation mode may be determined from the input voltage and the inductor current. Accordingly, a sinusoidal voltage at the fundamental frequency of the input voltage may be synthesized by selectively switching between adjacent operation modes of the set of operation modes.

Abstract: Control method for a washing household appliance comprising a drainage pump unit with an impeller and a motor supplied with an alternating supply voltage of a determined frequency from among a plurality of possible preset frequencies. According to one implementation the method involves an adjustment stage in which the frequency of the motor supply voltage is regulated between the preset frequencies. The method also includes an application stage in which a stator voltage is applied to the motor, the frequency of the motor supply voltage being regulated between the preset frequencies in accordance with the stator voltage applied.

Abstract: The Electric Power Converter functions as an uninterruptable power supply, battery management, energy conversion, micro-grid formation, and Power Factor Correction including Total Harmonic Distortion correction in real time. Uninterruptable power supply's use is for always-on, real-time, reduced distortion with functions of load reduction and management during peak load events. The Electric Power Converter is able to establish and sustain a micro-grid with multiple and varying sources of power generation and load conditions. The Electric Power Converter achieves dynamic, real-time, interactive Power Factor Correction (PFC) and advanced voltage harmonic distortion correction with a high efficiency ratio. The Electric Power converter is designed to function with the emerging Smart Grid technologies and provide an overall higher level of operating efficiency and higher quality of electrical power.

Abstract: Embodiments are disclosed relating to an electric power conversion device and methods for controlling the operation thereof. One disclosed embodiment provides a multi-stage electric power conversion device including a first regulator stage including a first stage energy storage device and a second regulator stage including a second stage energy storage device, the second stage energy storage device being operatively coupled between the first stage energy storage device and the load. The device further includes a control mechanism operative to control (i) a first stage output voltage on a node between the first stage energy storage device and the second stage energy storage device and (ii) a second stage output voltage on a node between the second stage energy storage device and the load.

Abstract: A period composed of a total of three periods, namely a period when an actual voltage vector is employed and periods before and after it can be regarded as an isolation period when an actual voltage vector is isolated in a vicinity where switching for commutation in a current-source converter is generated. When the switching in the current-source converter occurs at the isolation period, zero-current switching is realized. When presence of dead time is thus taken into consideration, a width of the timing when the zero-current switching is realized is made to be broader than a case where the presence of the dead time is not taken into consideration by the dead time.

Abstract: To aim to reduce ripple current flowing through a capacitor in a power converter apparatus including a converter, the capacitor and an inverter. A current sensor 6 is connected between a capacitor 5 and an inverter circuit 7 for detecting current Iinv flowing from the capacitor 5 to the inverter circuit 7. A frequency detecting subunit 11 performs fast Fourier transform on a waveform of the current Iinv to detect a frequency of a frequency component having the largest amplitude. Also, the frequency detecting subunit 12 detects a zero-cross point of the frequency component having the largest amplitude. Then a carrier signal control subunit 13 performs control such that a frequency and a rise time of a PWM carrier signal for driving the converter circuit 4 match the frequency and the zero-cross point that have been detected by the frequency detecting subunit 11 and the phase detecting subunit 12.

Abstract: A current estimation section of a motor control apparatus carries out the following processing. When an AC motor is controlled under a current feedback control scheme (sine wave control mode or overmodulation control mode), a ?-axis current i? is calculated based on a current detection value iw_sns in a sensor phase and a current command value iv* in one other phase. When the AC motor is controlled under a torque feedback control scheme (rectangular wave control mode), the ?-axis current i? is calculated based on a differential value ?i? of an ?-axis current. Then a sensor phase reference current phase ?x is calculated to estimate a U-phase current. Thus it is possible to use the current feedback control scheme and the torque feedback control scheme together.

Abstract: Exemplary embodiments are directed to a method and switching arrangement for an inverter. The inverter including a positive direct current pole, a negative direct current pole, and a neutral direct current pole. The arrangement having a first controllable switch connected between the neutral direct current pole of the inverter and a virtual neutral point of an alternating current network supplied by the inverter; and/or a second controllable switch connected between the neutral direct current pole of the inverter and an earth potential of an alternating current network supplied by the inverter.

Abstract: A reference current phase sensing part of a sensor phase (W) calculates an ?-axis current i? and a ?-axis current i? in a fixed coordinate system formed with respect to a sensor phase as a base. The ?-axis current i? is calculated based on a sensed current iw.sns of the sensor phase and a ?-axis current i? is calculated based on command currents iu* and iv* of the other two phases (U, V) determined from a d-axis command current id* and a q-axis command current iq*. Then a current phase x?=tan?1(i?/i?) is calculated. A basic wave estimating part calculates an estimated current iu.est of the other phase by calculating an estimation coefficient corresponding to the reference current phase x? of the sensor phase and multiplying the sensed current iw.sns of the sensor phase by the estimation coefficient.