Abstract: Systems and methods to improve operation of a modular multilevel converter. Some embodiments include a first upper arm with a first active power link module, which facilitates producing a first portion of a first alternating current electrical power at a base frequency and injecting a first even-order current harmonic of the base frequency in the first upper arm, and a first lower arm with a second active power link module, which facilitates producing a second portion of the first alternating current, in which the first portion of the first alternating current and the second portion of the alternating current are combined to facilitate outputting the first alternating current electrical power at a first alternating current terminal, and injecting the first even-order current harmonic in the first lower arm, in which magnitude of the first even-order current harmonic is zero at the first alternating current terminal.

Abstract: A pulse generator is disclosed that includes at least the following stages a driver stage, a transformer stage, a rectifier stage, and an output stage. The driver stage may include at least one solid state switch such as, for example, of one or more IGBTs and/or one or more MOSFETs. The driver stage may also have a stray inductance less than 1,000 nH. The transformer stage may be coupled with the driver stage and/or with a balance stage and may include one or more transformers. The rectifier stage may be coupled with the transformer stage and may have a stray inductance less than 1,000 nH. The output stage may be coupled with the rectifier stage. The output stage may output a signal pulse with a voltage greater than 2 kilovolts and a frequency greater than 5 kHz. In some embodiments, the output stage may be galvanically isolated from a reference potential.

Abstract: An X-ray high voltage device according to an embodiment includes: an inverter circuit including a plurality of switching elements; acquiring circuitry configured to acquire information about an inverter current flowing through the inverter circuit; and controlling circuitry configured to determine, on the basis of the information about the inverter current, a first point in time at which the inverter current becomes substantially 0 and to exercise control by implementing zero current switching control on the switching elements at the first point in time and implementing zero voltage switching control on the switching elements at a second point in time excluding the first point in time.

Abstract: Electronic circuitry for independently adjusting color temperature and brightness of an LED light fixture is disclosed utilizing two wires. According to one embodiment, a color-tunable and dimmable LED light fixture has first and second LED light strings connected in an anti-parallel arrangement.

Abstract: A power conversion apparatus is provided in which an upper arm semiconductor device, a lower arm semiconductor device and a capacitor. At least either upper arm semiconductor device or lower arm semiconductor device constitutes a parallel-connected body. In an opposite arm against the parallel-connected body, a permissible element is provided. In the switching elements that constitute the parallel-connected body, a last off element and a non-last off circuit are identified. Inductance of a last off closed circuit where current flows through the last off element, reflux element in the opposite arm and the capacitor is smaller than inductance of a non-last off closed circuit where current flows through the last off element, reflux element in the opposite arm and the capacitor.

Abstract: A 3-level power conversion circuit, including a high potential terminal configured to receive a high potential from a direct current (DC) power source, a low potential terminal configured to receive a low potential from the DC power source, an intermediate potential terminal configured to receive an intermediate potential from the DC power source, and an alternating current (AC) terminal configured to output an AC, the 3-level power conversion circuit being configured to perform power conversion between the high, low and intermediate potential terminals and the AC terminal. The 3-level power conversion circuit further includes a switching element and a diode connected in series between the intermediate potential terminal and the AC terminal, where the diode, but not the semiconductor switching element, includes a wideband gap semiconductor, and an ampacity of the switching element is greater than an ampacity of the diode.

Abstract: A power conversion circuit board is a board on which a power conversion circuit which converts direct current to alternating current is mounted. A low voltage circuit to which a low voltage is applied and a high voltage circuit to which a high voltage is applied are separately disposed in different areas on the same board surface. Further, in the high voltage circuit, a part of a wiring is formed on the board surface, and another wiring includes a bus bar which is provided with a predetermined distance from the board surface.

Abstract: A control circuit converts power by controlling a phase difference between a switching phase of a plurality of switching elements of a first bridge circuit and a switching phase of a plurality of switching elements of a second bridge circuit such that the control circuit controls the phase difference to be smaller to reduce the output power. When the phase difference reaches a predefined lower limit value in a step-down mode of stepping down the input power, the control circuit controls an on-time of the plurality of switching elements of the second bridge circuit to be shorter while the phase difference is fixed at the lower limit value.

Abstract: A power conversion device includes a first switching unit connected between a DC power supply and an inverter circuit, a resonant circuit connected to the input of the inverter circuit and formed by connecting a capacitor, a reactor, and a second switching unit, and a control unit, wherein, during a resonant operation period in which the first switching unit is controlled to be off and the second switching unit is controlled to be on, the control unit controls the inverter circuit to shift from a mode in which current flows back through one of upper and lower arms of the inverter circuit to a mode in which current flows back through the other arm, and provides a period in which the upper and lower arms for every phase of the inverter circuit are turned on simultaneously.

Abstract: A half-bridge driver circuit is configured to generate drive signals based on control signals. A processing circuit is configured to generate high side and low side control signals based on a control signal. An edge detector is configured to generate first and second signals in response to rising and falling edges in the control signal. A state machine transitions between states in response to the first and second signals, and is configured to sequentially, in response to the first signal, set the high side and low side control signals low; in response to the second signal, set the high side control signal high and the low side control signal low; in response to the first signal, set the high side and low side control signals low; and in response to the second signal, set the high side control signal low and the low side control signal high.

Abstract: A method for operating an inverter and an inverter configured to convert DC power supplied from a DC power source into AC power supplied to an AC network by applying maximum power point tracking, MPPT, such that a harmonic content of an AC current supplied from the inverter to the AC network is kept within a predetermined maximum level, wherein during the converting the inverter is configured to detect a need to increase the harmonic content of the AC current supplied from the inverter to the AC network beyond the predetermined maximum level, perform a check whether an increase of the harmonic content of the AC current beyond the predetermined maximum level is allowed, and, if an increase of the harmonic content of the AC current beyond the predetermined maximum level is allowed, raise the predetermined maximum level used in the converting.

Abstract: A power conversion device includes: an inverter for supplying high-frequency power to a coil; a harmonic filter connected to an output side of the inverter; and a controller for performing control to make a zero-cross point of an output current from the inverter coincide with a zero-cross point of a filter current of the harmonic filter. Through this, harmonic reduction effect can be fully exerted. Further, a contactless power supply system using the power conversion device can supply, to a load, power in which harmonics are significantly reduced, addressing a problem that inverter driving frequency cannot be controlled to a frequency at which harmonic reduction effect is maximized, and harmonic reduction effect cannot be fully exerted.

Abstract: A motor drive device includes a power conversion unit configured to selectively execute a converter operation of converting AC power into DC power, and an inverter operation of converting DC power into AC power for motor driving, a power storage unit configured to store DC power output from the power conversion unit and also supply DC power to the power conversion unit, a switching unit configured to switch between an AC power supply and a motor a connection destination of the power conversion unit, and a control unit configured to control the switching unit to have the power conversion unit connected to the AC power supply and control the power conversion unit to have the converter operation executed, and configured to control the switching unit to have the power conversion unit connected to the motor and control the power conversion unit to have the inverter operation executed.

Abstract: In certain embodiments, an apparatus includes an inductor having first and second terminals. The first terminal is configured to be coupled to a power source. The apparatus includes a pair of serially-coupled transistors coupled to the second terminal of the inductor. A transistor intermediate node is positioned between the pair of serially-coupled transistors. The apparatus includes a pair of serially-coupled diodes coupled to the second terminal of the inductor. A diode intermediate node is positioned between the pair of serially-coupled diodes. The apparatus includes a first capacitor coupled in parallel with the serially-coupled transistors and the serially-coupled diodes. The apparatus includes a sub-circuit having a second capacitor serially-coupled with an auxiliary transistor.

Abstract: A lighting system and a driving circuit thereof are provided. The driving circuit is configured to drive a light emitting device. The driving circuit includes a bulk voltage converter. The bulk voltage converter receives an input voltage and converts the input voltage to generate a driving voltage. The bulk voltage converter includes a snubber circuit, a power switch, and an inductor. The snubber circuit receives the input voltage through a first node and generates a snubber voltage at a second node according to the input voltage. The power switch is turned on or off according to a control signal. The inductor is coupled between the first node and a third node. The driving circuit is coupled to the light emitting device through the first node and the third node and provides the driving voltage to the light emitting device.

Abstract: A single-phase converter control method and apparatus, includes calculating on a voltage corresponding to a first level output by a single-phase converter, a voltage corresponding to a second level output by the single-phase converter, and a voltage reference value about the voltage corresponding to the first level and the voltage corresponding to the second level to obtain a common-mode modulated-wave change rate of the single-phase converter, where the first level is a direct-current-side positive-bus level, and the second level is a direct-current-side negative-bus level, calculating on a first-phase initial modulated wave of the single-phase converter, a second-phase initial modulated wave of the single-phase converter, and the common-mode modulated-wave change rate to obtain a common-mode modulated wave of the single-phase converter, and calculating on the first-phase initial modulated wave, the second-phase initial modulated wave, and the common-mode modulated wave to obtain a pulse width modulated wave

Abstract: A power supply device includes a PF correction circuit, a power switching circuit and a control circuit. The PF correction circuit converts an input voltage to a bus voltage according to a control signal to supply a later stage circuit. The power switching circuit selectively switches to conduct a first source or a second source to the PF correction circuit to provide the input voltage to the PF correction circuit. The control circuit outputs the control signal to the PF correction circuit. When the control circuit detects a first voltage of the first source connecting to the PF correction circuit is abnormal, the control circuit determines whether a second voltage of the second source is smaller than the bus voltage and controls the power switching circuit to switch when the second voltage is smaller than the bus voltage to conduct the second source to the PF correction circuit.

Abstract: A control circuit for a DC-DC converter and a DC-DC converter are disclosed. The control circuit includes an integrator coupled to receive a first reference voltage and a first voltage that includes an output voltage for the DC-DC converter and to provide an integrated error signal. A first comparator is coupled to receive the first reference voltage and the first voltage and to provide a dynamic-integration signal that adjusts the integration time constant of the integrator.

Abstract: This conversion device includes: a DC bus with a smoothing capacitor; a first converter provided between a DC power supply and the DC bus to perform DC/DC conversion; a second converter provided between the DC bus and an AC electric path to perform DC/AC or AC/DC conversion by a full-bridge of switching elements; a voltage sensor for detecting voltage between both ends of the capacitor as DC bus voltage; and a control unit which causes a part of an absolute value of an AC waveform, and a DC waveform, to alternately arise as the DC bus voltage by selectively causing the first converter and the second converter to operate in one AC cycle of the AC electric path, the control unit detecting arm short-circuit in the second converter on the basis of a degree of reduction, in the DC bus voltage, that occurs during operation of the second converter.

Abstract: The invention relates to a drive system, in particular for a vehicle, comprising a fuel cell unit for generating electric energy, a secondary battery for storing electric energy, an electric machine with windings, and an inverter for actuating the electric machine. The inverter is designed as a 3-level inverter and has multiple electronic switches, diodes, a plus pole, a minus pole, and a neutral pole. The fuel cell unit and the secondary battery are connected in series and are connected to the poles of the inverter. The invention also relates to a method for heating a drive system according to the invention, wherein the switches of the inverter are actuated such that a short-circuit current path is produced between the poles of the inverter to which the fuel cell unit is connected.

Abstract: A semiconductor device includes a positive electrode-side semiconductor element, a negative electrode-side semiconductor element, a positive electrode plate, a negative electrode plate, an AC electrode plate, a positive electrode-side auxiliary electrode terminal, a negative electrode-side auxiliary electrode terminal, a positive electrode-side capacitor, and a negative electrode-side capacitor. The positive electrode plate is connected to a first positive electrode of the positive electrode-side semiconductor element. The negative electrode plate is connected to a second negative electrode of the negative electrode-side semiconductor element. The AC electrode plate is connected to a first negative electrode of the positive electrode-side semiconductor element and a second positive electrode of the negative electrode-side semiconductor element. The positive electrode-side capacitor is connected to the positive electrode plate and the positive electrode-side auxiliary electrode terminal.

Abstract: A power supply includes a reference voltage generator, a power supply phase, and an adjustor. During operation, the reference voltage generator produces a reference voltage. The power supply phase produces an output voltage to power a load as a function of an output voltage feedback signal derived from the output voltage and the reference voltage. The adjustor adjusts a magnitude of the reference voltage to maintain regulation of the output voltage with respect to a desired voltage setpoint.

Abstract: A fan apparatus has a drive circuit for an electrically-driven rotor, and includes a drive signal generating circuit portion for the electrically-driven rotor; an output stage including an upper MOSFET and a lower MOSFET; and a motor portion to be driven by the output stage. One of the upper MOSFET and the lower MOSFET is a braking MOSFET, while another of the upper MOSFET and the lower MOSFET is a non-braking MOSFET. The fan apparatus further includes a back-electromotive force supply portion arranged to supply, to the braking MOSFET, power by a back-electromotive force caused by rotation of the motor portion while a power supply voltage for the electrically-driven rotor is not being supplied; and an electromagnetic brake portion arranged to electromagnetically brake the motor portion by causing the braking MOSFET to enter an ON state through the power supplied by the back-electromotive force supply portion.

Abstract: A pulse width modulation method, a pulse width modulation system, and a controller are provided, which change a change rate of a common-mode component of a three-phase converter upon a change of a converter modulation degree, thereby improving stability and harmonic characteristics of the three-phase converter and implementing flexible adaptive adjustment. An example pulse width modulation method includes: obtaining initial three-phase modulation waves and a converter modulation degree; calculating a common-mode-component change-rate adjustment coefficient based on preset modulation parameters and the converter modulation degree; selecting a modulation wave having a minimum absolute value from the modulation wave set as a common-mode modulation wave; and performing waveform superposition on the initial three-phase modulation waves and the common-mode modulation wave to obtain output three-phase modulation waves.

Abstract: With the disclosed device, a control method is set forth to control the flow of power between an electrical source and an electrical load.

Abstract: A power electronic system for an electricity charging station having the following features: first busbars for feeding in an alternating current, second busbars for conducting away a direct current, a third busbar for grounding the system, ground cables connected to the first busbars, the second busbars and the third busbar, and power electronic assemblies for converting the alternating current into the direct current. The invention furthermore provides an electricity charging station including such a power electronic system.

Abstract: The present invention discloses a control method and device for a circuit with a bridge arm of a switch. The soft switching converter includes at least two bridge arms of the switch, and an auxiliary switch assisting in switching of a main switch of the bridge arm of the switch. The control method includes the steps of: S1. after controlling the auxiliary switch to be turned on for a first period of time, controlling main switches set at the same position of individual bridge arms of the switch to be simultaneously turned on; S2. after a second period of time following a time when the main switches set at the same position of individual bridge arms of the switch are simultaneously turned on, turning off the auxiliary switch. The present invention can reduce system loss and noise, so as to improve efficiency.

Abstract: A bridge circuit converts input direct-current voltage and outputs alternating-current voltage. A filter circuit attenuates a high-frequency component of the alternating-current voltage output from the bridge circuit. A clamping circuit is disposed between the bridge circuit and the filter circuit, and is capable of short-circuiting the output side of the bridge circuit. A control circuit has a first mode in which a switching element causes the alternating-current voltage to be output to the filter circuit at three or more voltage levels, and a second mode in which the switching element causes the alternating-current voltage to be output to the filter circuit at two voltage levels. When power conversion devices have their alternating-current side output paths connected and operate in parallel, at least one of the power conversion devices operating in parallel operates in the second mode.

Abstract: In described examples, an isolated DC-DC converter includes: an input node for receiving an input voltage; a transformer including first and second terminals; first and second low-side switches; and first and second high-side switches. The first low-side switch is coupled between the first terminal and a primary side ground. The second low-side switch is coupled between the second terminal and the primary side ground. The first high-side switch is coupled between the first terminal and the input node and is configured to be activated by a voltage at the second terminal. The second high-side switch is coupled between the second terminal and the input node and is configured to be activated by a voltage at the first terminal. Further, the isolated DC-DC converter includes a switch controller to cause the first and second voltages to alternatingly be zero by opening and closing the first and second low-side switches.

Abstract: Electric power devices and control methods are provided which automatically select a line voltage or phase voltage of an AC voltage supply. The electric power device includes a switchable circuit, a sensor and a switch control. The switchable circuit connects to the AC voltage supply, and includes multiple switchable elements. The sensor ascertains a voltage level of the AC voltage supply, and the switch control automatically establishes a configuration of the switchable circuit through control of the multiple switchable elements. The switch control couples the electric power device in a line-line (delta) configuration to the AC voltage supply when the voltage level is in a first voltage range, and a line-neutral (wye) configuration when the voltage level is in a second voltage range.

Abstract: A drive circuit of a power semiconductor switch includes: a pulse modulation circuit having a first terminal configured to receive a fault signal, an isolation transformer, and a pulse demodulation circuit; when there is no fault signal being received, the pulse modulation circuit outputs a first turn on pulse signal and a first turn off pulse signal via the isolation transformer and the pulse demodulation circuit to charge/discharge a gate capacitor of the power semiconductor switch, so as to drive the power semiconductor switch to be turned on and turned off at a first speed; when the fault signal is received, the pulse modulation circuit outputs a second turn off pulse signal via the isolation transformer and the pulse demodulation circuit to discharge the gate capacitor of the power semiconductor switch, so as to drive the power semiconductor switch to be turned off at a second speed.

Abstract: A variable voltage converter for an electric drive system has upper and lower switching devices in series between positive and negative buses. An inductance couples a junction between the switching devices to a DC battery. A controller is configured to drive the switches according to PWM gate signals based on an expected boost ratio of the converter. The PWM gate signals have a nominal dead-time insertion for both the upper and lower switching devices when the expected boost ratio is greater than a predetermined boost ratio. In order to extend a range of achievable boost ratios during regeneration operation, the PWM gate signals are without dead-time insertion for the upper switching device and the lower switching device remains continuously off when the expected boost ratio is less than the predetermined boost ratio.

Abstract: A reconfigurable power converter is provided that includes a pulse-width modulation (PWM) controller. The PWM controller is configured to switch between a first modulation scheme and a second modulation scheme when a current-level property crosses a transition threshold.

Abstract: The various implementations described herein include inverter devices and systems. In one aspect, an inverter includes: a case; a capacitor within the case having a first terminal and a second terminal; a first bus bar including a first portion within the case and a second portion extending from the case to contact a first transistor; a second bus bar including a first portion situated in the case and a second portion extending from the case to contact a second transistor; and a phase-out bus bar including a first portion situated in the case, a second portion extending from the case to contact the first transistor, and a third portion extending from the case to contact the second transistor.

Abstract: An onboard charger for both single-phase (level-1 and level-2, up to 19.2 kW) and three-phase (level-3, above 20 kW) charging of a battery in Plug-in Electric Vehicles (PEVs) is integrated with the Propulsion machine-Inverter Group residing in the PEV, and is controlled to operate in propulsion and battery charging modes. The subject integrated onboard charger provides battery charging at the rated power of the Propulsion machine, does not need motor/inverter rearrangement, does not require additional bulk add-on passive components, provides an effective input current ripple cancellation, and operates without rotation of the Propulsion machine during the steady state charging.

Abstract: This disclosure is related to the technical field of magnets, and in particular to a method for applying a coupled inductor to a DC-DC converter providing a DC current output, and based on the number of phases of the DC-DC converter, the coupled inductor is designed to have a corresponding number of windings, the windings are reversely coupled to cancel out the magnetizing fields to avoid flux saturation of the magnet material under high current excitation, and the coupled inductor has air gaps, the leakage flux in the air gap induced by each winding is in the same direction, the leakage magnetic flux is used to achieve the filtering of the output current.

Abstract: An apparatus for controlling a start sequence of an engine for a vehicle may include an engine, a motor configured to start the engine, a main switch configured to connect power to the motor or interrupt the power to be supplied to the motor, a main battery configured to supply the power to the motor through the main switch, a converter configured to step up a voltage of the motor by boosting reverse power through a reverse control operation, an auxiliary battery configured to supply the reverse power, and a converter controller configured to perform a pre-charging operation for a predetermined time through the reverse control operation when an ignition-ON signal is inputted, and close the main switch when the pre-charging operation is completed.

Abstract: An electrical power conversion apparatus includes a high-voltage bus bar, a low-voltage bus bar, and a relay bus bar which are integrated together in the form of a bus bar assembly. The high-voltage bus bar includes semiconductor-side high-voltage terminals and capacitor-side high-voltage terminals. The low-voltage bus bar includes semiconductor-side low-voltage terminals and capacitor-side low-voltage terminals. The relay bus bar includes a reactor-side relay terminal and a capacitor-side relay terminal 532. The capacitor-side high-voltage terminals, the capacitor-side low-voltage terminals, and the capacitor-side relay terminal are arranged in the form of a terminal array. The capacitor-side high-voltage terminals and the capacitor-side low-voltage terminals are arranged adjacent each other. The capacitor-side relay terminal is located at an end of an array of the capacitor-side high-voltage terminals and the capacitor-side low-voltage terminals.

Abstract: A system for dissipating regenerated electric energy produced by an electric actuator of an aircraft, the dissipating system including: a resistor; two switching arms, each switching arm being connected in series with the resistor, the two switching arms being connected together in parallel, each switching arm including two switches connected to one another in series, each switch including two terminals and a control grid, each switch being capable of being controlled by controlling the potential applied to the control grid thereof; and a measurement system capable of measuring the voltage at the terminals of each switch.

Abstract: A three-level I-type inverter includes first to fourth switching devices between first and second potentials, first to fourth diodes, and fifth and sixth diodes. The first to fourth diodes are respectively connected to the first to fourth switching devices in anti-parallel. Between a connection node of the first and second switching devices and a connection node of the third and fourth switching devices, the fifth and sixth diodes are connected in series and in anti-parallel with series connection of the second and third switching devices. A connection node of the fifth and sixth diodes is connected to an input node having intermediate potential. A connection node of the second and third switching devices is connected to an output node. The second switching device and diode are formed of a first reverse conducting IGBT. The third switching device and diode are formed of a second reverse conducting IGBT.

Abstract: A grid independent operation control unit includes a load current estimator to estimate a load current supplied to stand-alone power system in accordance with an output current of the inverter and an output voltage, and a feedback controller configured to PWM control the inverter at a duty ratio feedback calculated to cause the inverter to output an output voltage command value in accordance with the output voltage and the load current. The feedback controller is configured to PWM control the inverter at a duty ratio feedback calculated for output of a normalized output voltage command value obtained by normalizing the output voltage command value with the DC bus voltage in accordance with normalized output voltage obtained by normalizing the output voltage with the DC bus voltage and normalized load current obtained by normalizing the load current with the DC bus voltage.

Abstract: In some embodiments, upon detecting a fault condition, switching in a switched mode power supply is disabled only after a current switching cycle of the switched mode power supply is completed.

Abstract: An apparatus includes a first switch leg connected between a first input terminal and a first output terminal, the first switch leg comprising serially connected switches. The apparatus also includes a second switch leg connected between a second input terminal and the first output terminal, the second switch leg comprising serially connected switches. The apparatus further includes a third switch leg connected between an input voltage midpoint and the first output terminal. A controller controls the first switch leg, the second switch leg and the third switch leg, wherein the controller is configured to disable the second switch leg for a first time period and alternately enable the first switch leg and the third switch leg during the first time period, and to disable the first switch leg for a second time period and to alternately enable the second leg and the third leg during the second time period.

Abstract: In the present invention, a high-voltage DC/DC converter suitable for powering x-ray tubes and the like provides control of a voltage applied to a resonant circuit at least in part according to a timing of a monitored voltage on the resonator thereby compensating for variations in the parameter stability of the resonant circuit, nonlinearity in the resonant gain curve and frequency dependencies.

Abstract: A switching mode power converter circuit is disclosed, comprising a first high-side switch and a first low-side switch coupled in series between an input voltage level and a reference voltage level, a second high-side switch and a second low-side switch coupled in series between the input voltage level and the reference voltage level, and a control circuit for controlling switching operation of the first and second high-side switches and the first and second low-side switches. The first high-side switch has a larger on-state resistance than the second high-side switch and the first low-side switch has a larger on-state resistance than the second low-side switch. The control circuit is configured to, during an on-state of the first and second low-side switches, control the second low-side switch to switch to the off-state and control the first high-side switch to switch to the on-state, so that the first high-side switch and the first low-side switch are both in the on-state.

Abstract: A power conversion apparatus comprises a bidirectional conversion circuit that enables first conversion converting DC to AC and second conversion converting AC to DC and a filter circuit that is provided on an AC side of the bidirectional conversion circuit and that includes a capacitor. A control unit is provided for performing control such that the bidirectional conversion circuit makes the first conversion during the former stage of each half cycle of AC voltage, and such that the bidirectional conversion circuit makes the second conversion during the latter stage of each half cycle of AC voltage. The control unit performs control such that AC current of an opposite polarity to that of the AC voltage flows to the AC side during the former stage and AC current of the same polarity as that of the AC voltage flows to the AC side during the latter stage.

Abstract: A method of and system for controlling a DC midpoint of a multi-level inverter. The method includes receiving an input power signal from an AC power source at a multi-level motor control system that includes a DC bus and a multi-level inverter configured to supply a load, the DC bus having a DC midpoint, connecting a DC midpoint of a DC bus to a neutral point of the AC power source, while isolating a neutral point of a load supplied by the multi-level inverter from the DC midpoint, monitoring a voltage on the DC midpoint of the DC bus. In addition, the method may include controlling a voltage of the neutral point of the AC load based on imbalances in the load supplied by the multi-level inverter.

Abstract: An inverter apparatus includes a first switch, a second switch, a third switch, a fourth switch, a load detection unit, and a control unit. The first switch and the fourth switch form a first switch assembly, and the second switch and the third switch form a second switch assembly. The control unit selects a control mode to be that two switches of the first switch assembly are not turned off and at least one switch of the second switch assembly is turned off, or two switches of the second switch assembly are not turned off and at least one switch of the first switch assembly is turned off, or two switches of the first switch assembly and two switches of the second switch assembly are not turned off.

Abstract: An electronic brushless variable transformer. Variable autotransformers, use brushes, and as such, have moving parts requiring maintenance and periodic cleaning of the brushes. A variable transformer without brushes is advantageous in that it eliminates the cleaning and maintenance of brushes.

Abstract: The present disclosure relates to a battery load drive system, and more particularly, to a battery load drive system for preparing for a surge current generated by a capacitor when a battery is coupled to a battery using a path for reducing current additionally provided in an existing path.