Abstract: A pulse width modulation method has the steps of operating a second instruction signal so that each of the differences between two or three arbitrary instruction signals in three first instruction signals may become more than the predetermined value, and modulating in pulse width based on the second instruction signal.

Abstract: A method for controlling a three-level inverter with a two-level inverter controller uses a conversion circuit to process the two-level control signals and output a set of three-level control signals.

Abstract: Embodiments of the invention relate to devices and methods for converting or buffering a voltage including an inductor configured to perform at least a primary function and to be reused to contribute to converting or buffering the voltage as a secondary function.

Abstract: A signal converter for generating switch drive signals for a multi-level converter comprises an input for a first pulse-width-modulation signal and a second pulse-width-modulation signal and an input for a polarity signal indicating a first polarity or a second polarity. The signal converter comprises four outputs for four switch drive signals for driving four switches of the multi-level converter. Also, the signal converter comprises a logic circuit for driving the switch drive signals in dependence on the polarity signal. The logic is configured to drive the switch drive signals in dependence on the polarity signal.

Abstract: An exemplary direct current to alternating current converter includes a pulse width modulator having a plurality of pulse signal outputs that can provide a plurality of pulse signals, a driving circuit having a plurality of switching units, and a transformation circuit having a plurality of transformers. Each of the switching units includes a P-type transistor and an N-type transistor. Each pulse signal output is electrically connected to the P-type and N-type transistors of one of the switching units. Each of the transformers is connected to two of the switching units, and the P-type transistors and the N-type transistors of the two switching units are not switched on simultaneously.

Abstract: A voltage drive system is provided having a plurality of modulators and a plurality of cascaded switching circuits which collectively generate a single-phase output signal to a load. Each modulator receives a phase current error and has an adder which generates a modulated phase current error based on the phase current error and based on a signal having a phase. For each respective modulator, the phase of the respective signal is different. Each respective modulator changes a respective gate input when the respective modulated phase current error changes from being within a predetermined current range to being outside of the predetermined current range. Each respective switching circuit receives the respective gate input and generates a respective output terminal voltage based on the respective gate input. The change in the respective gate input effectively causes a switching event of the respective switching circuit.

Abstract: A power conversion system comprises: a source of multiphase high frequency alternating current (AC) electrical input power; a high frequency controlled magnetics transformer for each phase of the multiphase high frequency AC input power, with each transformer having a primary winding coupled to its respective phase of the multiphase high frequency AC input power, at least one secondary winding that produces high frequency AC output power and at least one control winding responsive to a direct current (DC) control signal that changes the high frequency output power in proportion to the amplitude of the DC control signal; a power converter that receives the multiphase high frequency AC output power from each high frequency transformer secondary and converts it to system output power without the high frequency AC content; and a system controller responsive to the system output power that produces a DC control signal for each control winding that changes in amplitude in response to changes in a measured parameter

Abstract: A device for transmitting electric power between alternating voltage networks includes converters interconnected by direct current lines and provided each with several six-pulse conversion bridges. The six-pulse conversion bridges of one same converter are capable of being connected to an alternating voltage network associated with the converters via inductances differently phase-shifted. A control unit is provided to energize the valves of the six-pulse conversion bridges. The device is more economical and the converters are interconnected by a plurality of direct current circuits, each direct current circuit being galvanically separated from at least an alternating voltage network.

Abstract: An apparatus and method for controlling an inverter capable of enhancing reliability of current measurement by ensuring an optimal time for which effective voltage vectors are applied to detect a three-phase current according to a phase current and sizes of the effective voltage vectors, the apparatus comprising a space voltage modulator that generates and outputs effective voltage vectors based upon a voltage command value, and a low modulation determiner that determines whether the effective voltage vectors are located within a low modulation region, and outputs a low modulation switching control signal or a normal modulation switching control signal according to the determination.

Abstract: A controller for an induction motor includes a storage device which stores values in a plurality of addresses, a first counter which transits circularly among first to N-th states, a second counter which transits circularly among first to fourth states, a calculating section which calculates calculation values, and a signal generation section which generates PWM signals and synchronous interruption signals at constant time pitch such that pulse widths of the PWM signals are adjusted based on the calculation values respectively. An inverter supplies electric power to an induction motor based on the PWM signals. The first counter transits from one to next of the first to N-th states synchronously to each of the synchronous interruption signals. The second counter transits from one to next of the first to fourth states synchronously to each transition of the first counter from the N-th state to the first state.

Abstract: A DC/AC cold cathode fluorescent lamp (CCFL) inverter circuit includes a transformer with a primary winding and a secondary winding for providing increased voltage to a CCFL, a first and second MOSFET switches for selectively allowing direct current of a first polarity and a second polarity to flow through the transformer respectively. The primary and secondary windings of the transformer are electrically coupled to ground. A capacitor divider is electrically coupled to the CCFL for providing a first voltage signal representing a voltage across the CCFL. A first feedback signal line receives the first voltage signal. A timer circuit is coupled to the first feedback signal line for providing a time-out sequence of a predetermined duration when the first voltage signal exceeds a predetermined threshold. A protection circuit shuts down the first switch and the second switch when the first voltage signal exceeds the predetermined threshold after the predetermined duration.

Abstract: An electric power conversion system includes a DC power supply, plural main circuit switching devices bridge-connected to carry out DC/AC convert, having freewheeling diodes connected in reverse parallel thereto, respectively, and a reverse voltage application circuit for applying a reverse voltage smaller than the DC power supply to each freewheeling diode, upon a cutoff of back-flow current of the freewheeling diode, the reverse voltage application circuit being composed of a series connection of a low-voltage DC power supply, a reverse voltage application switching device having a lower withstand voltage than the main circuit switching devices and adapted to turn on upon a reverse recovery of the freewheeling diode, and an auxiliary diode having a shorter reverse recovery time than the freewheeling diode, the reverse voltage application switch being a device having holes as a majority carrier.

Abstract: An inverter driving circuit for an LCD is switched on/off more stably to improve heating radiation characteristics and drive efficiency. In the driving circuit, a controller supplies a first driving signal. A level shifter provides a second driving signal. A first delay circuit delays a rising section of the first driving signal to provide the first driving signal. A second delay circuit delays a falling section of the second driving signal to provide the second driving signal. Also, a power switching circuit is provided. The inverter driving circuit for the LCD, when a switching device thereof is turned off, has less current flowing in the switching device, thereby generating less heat. In addition, the inverter driving circuit prevents heat generation caused by current flowing reversely in the switching device, thereby enhancing drive efficiency.

Abstract: A zero voltage switch half bridge converter comprises a first and second diode series diodes, parallel with a voltage source. A first terminal of an inductor is joined to the diode junction. A first semiconductor auxiliary switch connected in series between the voltage source and a third diode, which is in series with a fourth diode connected to a second semiconductor auxiliary switch. First and second semiconductor main switches are connected in series and in parallel with the voltage supply. A capacitive voltage divider connected across the voltage source, wherein a second terminal of the inductor is connected to junction of the main switches and a midpoint of the capacitive voltage divider. A control circuit is configured to provide respective control signals to at least the first semiconductor auxiliary switch and the second semiconductor auxiliary switch.

Abstract: A phase-shifted PWM dc-to-dc converter includes a pair of switched half-bridges defining taps. The primary of an output transformer is coupled across the taps to receive AC, and produces transformed AC which is rectified and filtered to produce the output dc. Zero-voltage-switching (ZVS) is maintained over the full range from zero load current to maximum load current by the use of an auxiliary circuit including an “inverting” second transformer having primary and secondary windings serially coupled with capacitors. The primary-capacitor serial circuit is connected between a first half-bridge tap and reference potential, and the secondary-capacitor serial circuit is connected by an inductance between second half-bridge tap and a reference potential.

Abstract: A method and inverter (2, 27) for converting a DC input voltage supplied by a DC source (9), which is in particular a solar cell array, into a 3-phase AC output. For each phase (R, S, T) the DC input voltage is converted to a DC output voltage (DCR, DCS, DCT) with a specific waveform. The waveforms of the three DC output voltages are identical, shifted in time by 120° to each other and they are such that by subtracting any two of them a sinusoidal waveform is obtained. The waveform of each DC output voltage may comprise a first portion of ? or 120° of the AC output cycle with an amplitude of zero and a subsequent second portion of ? or 240° of the AC output cycle during which the DC output voltage has a non-zero amplitude.

Abstract: An insulated transfer device with particular topology, comprising on the primary, a switched-mode voltage step-up circuit, with a step-up inductance (LB) and an active buffer stage (DT, MT, CT) supplying a peak voltage greater than the peak voltage supplied by the input voltage source (vE) and two pairs of controlled switches controlling the application of the voltage supplied by the switched-mode voltage step-up circuit, to the terminals (Ep1, Ep2) of the primary winding and to the secondary, a full-wave rectifier with diodes (Ds1, Ds2) and controlled switches (Ms1, Ms2). On the primary, the voltage at the terminals of the capacitor CT of the active buffer stage used to apply a controlled AC voltage between the terminals Ep1 and Ep2 is regulated by controlling the time for which the controlled switches of the pairs are simultaneously in the closed state. On the secondary, VS is regulated by controlling the time for which the secondary switches are simultaneously in the closed state.

Abstract: In order to prevent a short circuit of top and bottom arms of a motor driving IC when noise is added to six control signals for controlling six switching elements, there is provided a semiconductor device for driving a motor, being sealed with resin as one package and comprising: six switching elements for driving a three-phase motor; three output terminals for outputting voltages to the three-phase motor; at least one driving circuit for driving the six switching elements; three control signal input terminals; and a function) of generating six control signals for control of the six switching elements based on three control signals inputted through the three control signal input terminals.

Abstract: A switching power supply apparatus includes a transformer or an inductor, a switching element connected to the transformer or the inductor and configured to perform switching of an input power supply, and a switching control circuit including a digital control circuit configured to sample voltage values and/or current values and control on and off of the switching element in accordance with the voltage values and/or current values. The number of points of sampling is set to n or more points, where n is an integer greater than 3, in an ON period of the switching element except at around a turn-on point or a turn-off point of the switching element. The presence or absence of magnetic saturation of the transformer or the inductor is detected on the basis of whether or not a slope of change in current value over time is larger than a predetermined value, and circuit operation is protected from the effect of magnetic saturation.

Abstract: The configurations of a non-contact power supply and a coupling detection method thereof are provided. The proposed non-contact power supply includes a detachable transformer including a primary side, a current sensor coupled to the primary side and sensing a primary side current and a controller coupled to the current sensor, receiving the current and determining whether the power supply is under a coupling status according to the current.

Abstract: When the three U-, V-, W-phase arms of a DC/DC converter are turned on, they are alternately turned on by gate drive signals. When the U-, V-, W-phase arms are alternately turned on, an upper arm switching device of the U-phase arm, for example, is turned on, and thereafter a lower arm switching device of the U-phase arm is turned on. Thereafter, an upper arm switching device of the V-phase arm which is next to the U-phase arm is turned on, and thereafter a lower arm switching device of the V-phase arm is turned on. The upper and lower arm switching devices are thus turned on in a rotation switching process.

Abstract: A method and circuit enabling off-the-shelf controllers designed for use with a two-level AC drive inverter bridge (1920) to drive inverter bridges with three-or-more levels. Signals from an ordinary induction motor controller or a two-level induction motor controller (2200) are used to drive the twelve-or-more switches of a three-or-more level inverter bridge (1920), as are used in medium-and-high voltage applications. The proper sequence and timing of switching for the three-or-more-level inverter bridge is based in-part upon either the output of the six pulse-width modulators, or the output of the flux and torque control device, or the voltage control device (2210), of the two-level controller (2200).

Abstract: A dc-ac converter capable of supplying a finely regulated ac drive voltage to a load is provided. For this purpose, the converter includes, in a primary winding of a transformer, a full-bridge or half-bridge type semiconductor switch circuit whose switch can be controlled by pulse-width modulation. Transformer has a secondary winding for connection with a load. Based on PWM signals and by use of adequate switching logics for controlling multiple semiconductor switches, sophisticated control including zero-current switching and penetrating current prevention can be effected. Moreover, by means of regulated burst control of the ratio of on-duty period to off-duty period together with pulse-width modulation control, power supplied to the load can be regulated over a wide range beyond the limits of control obtained by the pulse-width modulation.

Abstract: An adaptive hybrid energy system is provided. The system includes a first DC energy source that generates a first DC output by converting a first type of energy into an electrical output. Additionally, the system includes at least a second DC energy source that generates a second DC electrical output by converting a second type of energy into an electrical output. The system further includes a cascaded multilevel converter electrically connected to the first and second DC energy sources to convert a DC electrical output into a sinusoidal electrical output when at least one of the first and second DC energy sources is operable.

Abstract: An inverter (1) for feeding electric power into a utility grid (7) or into a load is described. The inverter (1) contains direct voltage inputs (2, 3), one first intermediate circuit (8) connected thereto and comprising two series connected capacitors (C1, C2) that are connected together at a ground terminal (14), two alternating voltage outputs (5, 6) of which one at least is provided with a grid choke (L1) and one bridge section (10).

Abstract: To provide a power converter, comprising: a pair of main circuit switching elements to which diodes are connected; a means for generating a first PWM basic signal for driving a main circuit switching element; and a reverse voltage application circuit to be operated, triggered by a second PWM basic signal which differs from the first PWM basic signal only in phase.

Abstract: Provided is a flux regulation method for use in a power converter, wherein the method is carried out by a flux bias controller. The flux bias controller includes a current detector which is configured to detect the primary current of the transformer of the power converter in a predetermined switching cycle, a DC bias processor which is configured to obtain the duty ratio control signal according to the sampled primary current outputted from the current detector for a switching cycle later than the predetermined switching cycle, and a PWM controller which is configured to generate driving signals to control the on/off operations of the switching circuit of the power converter according to the duty ratio control signal, thereby suppressing the DC bias of the transformer by regulating the duty ratio of the switch circuit.

Abstract: A method of controlling a series-resonant, half-bridge inverter includes turning off the bottom switch and turning on the top switch the inverter when the current through the resonant inductor crosses the zero axis while the current is increasing, thereby insuring zero voltage switching of the inverter switches and increases the overall switching period so that the actual inverter frequency is closer to the resonant frequency of the series-resonant circuit. Using an on-time control circuit, the method further includes controlling the current delivered to the load (such as a gas discharge lamp) by varying the on-time of the top inverter switch.

Abstract: A semiconductor element (20) of the present invention includes a plurality of field effect transistors (90) and a schottky electrode (9a), and the schottky electrode (9a) is formed along an outer periphery of a region where the plurality of field effect transistors (90) are formed.

Abstract: The invention concerns an electric converter for fuel cell (P) comprising current inverter means (2), the electric converter comprising a voltage step-down chopper (1) mounted between the fuel cell (P) and the current inverter means (2), wherein, under the action of a command signal applied to the voltage step-down chopper (1): the value of the mean voltage at the input of the current inverter means is lowered to a threshold value (Vs) in the cell electrode activation zone, the value of the mean voltage at the input of the current inverter means (2) is maintained at the voltage value at the cell terminals (Vp) in the cell resistance zone, and the output current of the converter is limited when the output current from the current inverter means (2) reaches a maximum set value (Imax).

Abstract: A microsource is provided, which includes an inverter, an energy storage device, and a controller. The controller calculates a maximum frequency change for the inverter based on a first comparison between a first power set point and a measured power from the inverter. The first power set point is defined based on a charge level of the energy storage device. A minimum frequency change for the inverter is calculated based on a second comparison between a second power set point and the measured power from the inverter. An operating frequency for the inverter is calculated based on a third comparison between a power set point and a measured power flow. A requested frequency for the inverter is calculated by combining the maximum frequency change, the minimum frequency change, and the operating frequency. The requested frequency is integrated to determine a phase angle of a voltage of the inverter to control a frequency of an output power of the inverter.

Abstract: A method is disclosed for the operation of a converter circuit, wherein the converter circuit has a converter unit having a multiplicity of actuatable power semiconductor switches and an LCL filter which is connected to each phase connection of the converter unit, in which the actuatable power semiconductor switches are actuated by means of an actuation signal (S) formed from a hysteresis active power value (dP), from a hysteresis reactive power value (dQ) and from a selected flux sector (?n). The hysteresis active power value (dP) is formed from a differential active power value (Pdiff). In addition, the hysteresis reactive power value (dQ) is formed from a differential reactive power value (Qdiff). An apparatus for carrying out the method is also disclosed.

Abstract: Primary and secondary regions are electrically insulated from each other. The first and second pulse transformers are provided to the respective transistors in the switching circuit. Secondary windings of the first and second pulse transformers are connected to control terminals of the transistors. The control circuit supplies switching voltages to primary windings of the pulse transformers based on a feedback signal fed back through a feedback line. A primary winding of a transformer, the switching circuit, and the secondary windings are disposed on the primary region. A secondary winding of the transformer, the primary windings, the feedback line, and the control circuit are disposed on the secondary region.

Abstract: The power converter for solving the above-described problem has a module section and a drive section for operating the module section. The drive section has a drive circuit. The drive circuit is provided so as to correspond to the first semiconductor element which is one of the semiconductor elements comprising the parallel circuit; wherein drive signals for operating the first semiconductor element are output. The drive signals that are output from the drive circuit are electrically branched and output to a second semiconductor element which is a separate semiconductor element from the first semiconductor element of the semiconductor elements comprising the parallel circuit. As a result, the second semiconductor element receives the branched drive signals and operates in the same manner as the first semiconductor element. Thereby, a motor converter favorable for control large current at a low cost is provided.

Abstract: A computer assembly having a processor integrated circuit, a hard disk drive electrically connected to the processor units and a power supply assembly, powering the processor integrated circuit and hard disk drive. These components are sealed in an liquid-tight case defining fluid channels. Electrical connectors permit connection of the processor to outside devices. Finally, a fan in the liquid-tight case, adapted to drive fluid through the fluid channel, thereby facilitates the movement of heat through the computer assembly and creates a monolithic thermal structure. In one embodiment, the computer assembly is powered by a raw DC power supply input and self manages this power input source to provide consistent and reliable power to the computer assembly without burdening the raw DC power supply during transient conditions.

Abstract: Methods and systems for controlling a power inverter are provided. In accordance with one embodiment, a system for converting a direct current into an alternating current may include a switching module, a sensing module, and a control module. The switching module may have an input and an output, and may be operable to receive a direct current at the input and to generate at the output a corresponding alternating current with a desired output characteristic. The sensing module may be coupled to the switching module output, and may be operable to sense a power factor associated with a load coupled to the switching module output. The control module may be coupled to the power inverter and the sensing module, and may be operable to control the desired output characteristic based at least on the sensed power factor.

Abstract: A converter includes a converter for an ion propulsion system is provided. The converter includes a bridge circuit with a first and second bridge circuit connection and four switches. The converter also includes a storage inductance and a high voltage transformer with a primary and a secondary winding. The converter further includes a switch control unit, which opens or closes the fourth switch at a control time delayed in relation to the first switch.

Abstract: A half-bridge resonant converter includes: a primary winding; a secondary winding having a first and a second end and a central point; a first electronic switch; a second electronic switch; a first power-storage element; a second power-storage element; and a load having a first and a second end. Wherein, the first end of said the secondary winding serially connects with said the first electronic switch and the first power-storage element, and the second end of said the secondary winding serially connects with said the second electronic switch and the second power-storage element, and the first end of said the load connects simultaneously with said the first power-storage element and the second power-storage element, and the second end connects with the central point of the secondary winding.

Abstract: A method of controlling an inverter to includes determining the components of a phasor representing the output current from the inverter in a fixed reference system; determining the components of the current phasor in a reference system rotating at a velocity equal to the velocity of rotation of the phasor representing the grid voltage; and comparing the components of the current phasor in the rotating reference system with a reference, again expressed in the rotating reference system, to determine an error signal, by means of which the inverter is controlled.

Abstract: The control device of an electric power converter comprises a control circuit controlling turn-on of power semi-conductor arms. The control circuit comprises a module for determining possible turn-offs of an arm, and a module for selecting turn-offs enabling double switching from among the possible turn-offs. Selection of turn-offs enabling an arm of said converter to be turned off according to the turn-offs enabling double switching in other arms. The electric converter comprises one such control device. The method comprises determination of turn-offs enabling double switching from among the possible turn-offs, and selection of turn-offs to turn an arm of said converter off according to the turn-offs enabling double switching.

Abstract: Proposed is a power semiconductor module with a housing and one or a plurality of half-bridge circuitries arranged therein. Each half-bridge circuitry has a first (TOP) and a second (BOT) power switch and each switch is comprised of one power transistor and a corresponding power diode (recovery diode). The power semiconductor module furthermore has a positive polarity direct current lead and a negative polarity direct current lead. Per each half-bridge circuitry it furthermore has two alternate current leads that are not directly connected electrically. Each TOP transistor is connected to the power diode of the BOT switch and a first alternate current lead and each BOT transistor is connected to the power diode of the TOP switch and a second alternate current lead.

Abstract: The inverter device contains three sets of series circuit formed by connecting two switching elements (2) in series between a positive terminal and a negative terminal of DC power supply (1). Connecting points of the two switching elements are connected to motor (11). DC voltage of DC power supply (1) is switched by PWM 3-phase modulation so that a sinusoidal wave-shaped AC current is fed to the motor. Upper-arm switching elements connected to the positive terminal of the DC power supply increase or decrease an ON period equally in all phases for a carrier cycle in the PWM 3-phase modulation so as to provide two conducting period in the carrier cycle.

Abstract: Disclosed is a bi-directional battery power inverter (1) comprising a DC-DC converter circuit element (3) to which the battery (2) can be connected in order to generate an AC output voltage from a battery (2) voltage in a discharging mode while charging the battery (2) in a charging mode. The inverter (1) further comprises an HF transformer which forms a resonant circuit along with a resonant capacitor (6). In order to increase the efficiency of said battery power inverter, the transformer is provided with two windings (11, 12) with a center tap (20) on the primary side, said center tap (20) being connected to a power electronic center-tap connection with semiconductor switches (21, 31) while a winding (13) to which the resonant capacitor (6) is serially connected provided on the secondary side.

Abstract: A control system for a power inverter is disclosed. The power inverter may be configured to supply power to a grid. The control system may include a plurality of output voltage sensors and a plurality of output current sensors configured to measure output line voltages and output line currents of the power inverter. The control system may further include a controller coupled to the power inverter. The controller may be configured to provide a control signal associated with a disturbance frequency to the power inverter. The controller may be further configured to determine an output power of the power inverter based on the output line voltages and output line currents, and determine an amplitude of oscillation in the output power caused by the disturbance frequency. The controller may also be configured to detect an islanding condition, if the amplitude of oscillation is below a threshold.

Abstract: A bidirectional active power conditioner includes a DC side, a bidirectional DC/DC power converter, a DC/AC inverter and an AC side. The DC side electrically connects with a DC source while the AC side electrically connects with a load and an AC source. The bidirectional DC/DC power converter is controlled via high-frequency pulse width modulation (PWM) switching so as to generate a predetermined DC voltage or DC current while the DC/AC inverter is controlled to convert the predetermined DC voltage or DC current into a predetermined AC voltage or AC current.

Abstract: A method for an inverter, for inputting power output by a direct current voltage source in an alternating current voltage network chops the direct current voltage source by a bridge inverter by alternate switching of parallel-mounted and series-mounted circuit elements, in the form of a pulse width modulation, and the chopped power is transmitted via a transformer which is connected between the series-mounted elements. The transmitted power is then rectified and input in the alternating current voltage network via a down-converter transformer. In order to adapt the inverter to the power supplied, the switching times of the circuit elements of the bridge inverter are controlled or regulated.

Abstract: A power converter and power conversion method wherein operation of a switching element is controlled by the frequency of a carrier wave where the frequency is varied such that the same frequency of the carrier wave is not repeated during a single modulation period.

Abstract: A semiconductor switch circuit is connected to a primary winding of a transformer having a secondary winding connected to a load. The semiconductor switch circuit has switches controlled by PWM to provide a controlled constant current. In the inventive inverter, constant current control is performed by PWM operation of the switches of the semiconductor switch circuit. The inverter cuts off electricity to the control circuit when putting the control circuit into a standby state if a run-stop signal gains a logical stop-state. At the same time as the run-stop signal gaining the stop-state, switch drive signals enabling the switches of the semiconductor switch circuit are turned off. Thus, over-current can be prevented from flowing in the load when the control circuit is put into the standby state.

Abstract: A DC-to-DC converter with improved transient response, accuracy and stability is disclosed. The DC-to-DC converter includes a comparator, a driver, at least one switch and a stability circuit. The stability circuit receives a voltage signal based upon sensing one of the at least one switch. The configuration with elimination a current sensing resistor can create a simpler solution for the DC-to-DC converter.

Abstract: This invention improves the performance and lowers the cost of DC to AC inverters and the systems where these inverters are used. The performance enhancements are most valuable in renewable and distributed energy applications where high power conversion efficiencies are critical. The invention allows a variety of DC sources to provide power thru the inverter to the utility grid or directly to loads without a transformer and at very high power conversion efficiencies. The enabling technology is a novel boost converter stage that regulates the voltage for a following DC to AC converter stage and uses a single semiconductor switching device. The AC inverter output configuration is either single-phase or three-phase.