Abstract: A method and apparatus for determining a corrected monitoring voltage, at least a portion of the method being performed by a computing system comprising at least one processor. The method comprises generating power at a first location; monitoring the generated power by measuring a first voltage proximate the first location; measuring a second voltage proximate a second location, the first and the second locations electrically coupled; and determining, based on the measured second voltage, a corrected monitoring voltage to compensate the measured first voltage for a distance between the first and the second locations.

Abstract: The present invention relates to a near zero current-ripple inversion circuit including top and bottom cells, a transformer (T1) comprising primary windings (P1, P2) and a secondary winding (S1), and at least one middle cell connected in series between the top and bottom cells. The top cell comprises two capacitors (C1, C2) and a switch (Q1) each connecting to the middle cell, and an inductor (Lr1) and the primary winding (P1) connected in series between the capacitor (C1) and switch (Q1), wherein the switch (Q1) is connected to the capacitors (C1, C2) respectively. The bottom cell comprises a capacitor (C3) and a switch (Q2) each connecting to the middle cell, and an inductor (Lr2) and the primary winding (P2) connected in series between the capacitor (C3) and switch (Q2), wherein the primary winding (P2) is connected to the middle cell, and the capacitor (C3) and switch (Q2) are connected.

Abstract: Power inverters are controlled in response to reactive power support commands received from a power grid such that at least one power inverter provides reactive power to the power grid. The reactive power provided is based on each power inverter's reactive power capacity only while the total power capacity of each power inverter providing the reactive power is not exhausted in generating real power.

Abstract: A fuel cell system FCS includes a fuel cell FC, a motor ES4 connected to the fuel cell FC, an FC boost converter ES6 which raises the output voltage of the fuel cell FC to output the voltage to the motor ES4, an inverter ES3, a current sensor S2, and a controller EC which controls the fuel cell FC, the FC boost converter ES6 and the inverter ES3. The controller EC controls the inverter ES3 so as to raise the target output voltage of the inverter, when the current detected by the current sensor S2 exceeds a predetermined current threshold value.

Abstract: A method and system for managing electrical loads on a standby generator. The method includes utilizing a transfer switch control to selectively shed loads each associated with one of a series of priority circuits. Priority values are initially assigned to each of the electric loads based upon the initial hard-wired connection of the electric loads to a main breaker panel during set up. The control unit of a transfer switch allows the user to reassign priority values to each of the electric loads based upon a user preference. The control unit includes one or more predefined priority assignment programs that can be selected to modify the priority values assigned to the electric loads.

Abstract: When determining a fault current portion IF in a differential current idiff(t) measured by an inverter, an AC voltage uAC(t) applied to an AC output of the inverter is measured and a periodic reference function y(t) of alternating sign is generated as a function of the measured AC voltage uAC(t) in order to determine an AC fault current portion IFAC in the differential current idiff(t). The differential current idiff(t) is multiplied by the periodic reference function y(t), and the product of the differential current idiff(t) and the reference function (y(t)) is averaged over an integral number of periods of the reference function y(t). The reference function y(t), at least for one operating state of the inverter, is generated with a predefined phase offset with respect to the measured AC voltage uAC(t) and/or with a frequency which is an integer multiple of the frequency of the measured AC voltage uAC(t).

Abstract: This invention relates to circuits and methods for controlling a resonant power converter. Control of the power converter may comprise comparing an output voltage or current of the converter to at least one reference voltage or current; enabling primary side switching signals based on a first selected result of the comparison; and disabling primary side switching signals based on a second selected result of the comparison; wherein a primary side switching signal for each primary side switch includes at least one off-on-off transition.

Abstract: A solar power system includes at least one alternating-current module and a communication apparatus. Each alternating-current module includes a solar panel and an alternating-current inverter. The communication apparatus connects to the alternating-current module and controls stand-alone power-generating operations on the alternating-current module. The communication includes a module connector and a control circuit. The module connector is configured for connecting with the alternating-current module. The alternating-current module can be parallel-connected on a household power grid selectively. The communication apparatus can transmit a stand-alone power-generating command to the alternating-current module. The alternating-current inverter may cancel an anti-islanding protection procedure thereon according to the stand-alone power-generating command.

Abstract: A switching power supply apparatus includes a low-side switching control unit and a high-side switching control unit. The low-side switching control unit includes a low-side turn-off circuit that turns off a low-side switching element behind a delay time when reversal of the polarity of a winding voltage of a transformer is detected during a period in which a drive voltage signal is supplied to the low-side switching element. The high-side switching control unit includes a high-side turn-on delay circuit that delays a time from the time when the polarity of the winding voltage of the transformer is reversed to a time when a high-side switching element is turned on. The delay time of the low-side turn-off delay circuit is set so as to be shorter than the delay time of the high-side turn-on delay circuit.

Abstract: A neutral point clamped three-phase three-level inverter is connected to a first DC power supply and single-phase inverters are connected in series with AC output lines of individual phases of the three-phase three-level inverter such that sums of output voltages of the three-phase three-level inverter and output voltages of the respective single-phase inverters are output to a load through a smoothing filter. An output control unit controls the three-phase three-level inverter so that the individual phases of the three-phase three-level inverter output primary voltage pulses at a rate of one pulse per half cycle and controls the individual single-phase inverters by PWM, so that output voltages to the individual phases of the load form sine waves of which phases are offset by 2?/3 from one phase to another, the sine waves having the same peak value.

Abstract: A power supply apparatus includes an AC-DC rectifier, a transformer, a feedback inductor, a resonant unit, and a primary and auxiliary switch. The AC-DC rectifier rectifies an input voltage. The transformer includes a primary coil having a first primary coil and an isolated second primary coil, and transforms a first voltage of the primary coil into a second voltage of the secondary coil. The feedback inductor is connected to a tap between the first primary coil and second primary coil and an output of the AC-DC rectifier. The resonance unit is connected in parallel with the secondary coil and is configured to output an output voltage by rectifying the second voltage provided from the secondary coil. The primary switch and secondary switch are connected in parallel between the transformer and AC-DC rectifier.

Abstract: A system simplification can be achieved by reducing the number of sensors required to detect currents and voltages when an output current is estimated. A switching power supply device 6 includes a current transformer 12, a switching circuit 13, a rectifying circuit 15, a smoothing circuit 16, an input voltage detecting circuit 18, a control part 19, an output voltage detecting circuit 22 and a PWM signal generating part 30. The control part 19 calculates a duty rate and an average value of voltage of the secondary side voltage of the current transformer 12 detected by the input voltage detecting circuit 18 based on a waveform of the detected voltage. The control part 19 calculates an output current lo based on the calculated duty rate, the calculated average value of voltage and an output voltage Vo detected by the output voltage detecting circuit 22.

Abstract: A power inverter is provided comprising: a control board comprising: a processor that generates an AC waveform from a pulse width modulation (PWM) signal according to instructions or data stored in a memory associated with the processor; and an output at which a signal having the AC waveform is provided; a power supply module that is connected to the control board, comprising: an input connected to the output of the control board at which the AC waveform signal is provided; and an output at which an AC power signal is provided on a channel of the power inverter.

Abstract: A Voltage Source Converter having at least one phase leg connected to opposite poles of a direct voltage side of the converter and including a series connection of switching cells has an arrangement configured to apply a pressure to opposite ends of stacks of semiconductor assemblies for pressing the assemblies towards each other so as to obtain electric contact between semiconductor assemblies in the stack while ensuring that the semiconductor assemblies of a first path of each switching cell of the converter go into a permanently closed circuit state in case of a failure of the respective switching cell. A second path of each switching cell has a member configured to keep the second path including an energy storing capacitor non-conducting upon occurrence of the failure.

Abstract: A power conversion apparatus includes an inverter circuit including a switching element, a system voltage measurement unit measuring a system voltage of a power system, a voltage drop detector detecting a voltage drop of the power system, a carrier wave generator generating a carrier wave, a carrier wave frequency modulator increasing a frequency of the carrier wave, when the voltage drop is detected, a signal wave generator generating a signal wave to control the inverter circuit, a gate signal generator comparing the carrier wave with the signal wave, and generating a gate signal, and a power conversion controller controlling the inverter circuit, based on the gate signal.

Abstract: A resonance power generator is provided. The resonance power generator includes an alternating current/direct current (AC/DC) rectifier to rectify an input signal of an alternating voltage and an AC generator to generate an AC signal based on the rectified signal that is output from the AC/DC rectifier. The resonance power generator may also include, for example, a control unit to control a frequency of the AC signal, a filter unit to remove a spurious signal or a harmonic element included in the AC signal, a voltage/current amplifier to amplify the AC signal, and a source resonator to transmit a power to a target resonator.

Abstract: Provided are a solar energy generation system having an adaptive maximum power point tracking function and a method thereof. The solar energy generation system includes: a minimum maintenance voltage determination unit configured to output a minimum maintenance voltage which enables the inverter to maintain an operation thereof corresponding to a grid voltage of the grid; a maximum power point tracking controller configured to determine a maximum power point tracking voltage at a maximum power point of the photovoltaic module, using the minimum maintenance voltage and an output voltage and output current of the photovoltaic module, and to output a reference voltage to track the maximum power point; a voltage calculator configured to calculate a difference between the reference voltage and the output voltage of the photovoltaic module; and a voltage adjuster configured to generate a reference current value using an output of the voltage calculator.

Abstract: A switching control IC conducts on-off control on a first switching element. A second switching control circuit is provided between a high-side driving winding of a transformer T and a second switching element. The second switching control circuit discharges a capacitor in a negative direction with a constant current during an on period of the first switching element, and then after the second switching element is turned on, charges the capacitor in a positive direction with a constant current. A transistor controls the on period of the second switching element in accordance with the ratio of a charging current to a discharge current such that the ratio of the on period of the second switching element to the on period of the first switching element is substantially always constant.

Abstract: A control section which repeats inverter control in units of an inverter control period having a predetermined length is provided. In the control section, a phase current detection period in which a phase current is detected is provided between predetermined two inverter control periods, each of switching states of switching elements of a inverter circuit is controlled so that a voltage pulse having a larger width than a width of a voltage pulse in the inverter control period is output from a shunt resistor in the phase current detection period.

Abstract: A power inverter system includes a plurality of power semiconductor switching devices. Each switching device includes a corresponding gate turn off resistance configured to increase during starting up periods of the inverter system such that the open circuit voltage of a corresponding power source providing power to the power inverter system does not exceed the switching device blocking voltage ratings during the corresponding switching turn-off periods. The starting up period is the time required to bring the corresponding power source voltage from its open circuit voltage level to a predetermined voltage which constitutes a safe operating condition for the plurality of power semiconductor switching devices.

Abstract: A power converter includes a main switch to which a capacitor is connected through a sub-diode. A series connection of a primary coil of a transformer and a sub-switch is connected parallel to the capacitor. A main diode is coupled in series with the main switch. A series connection of a sub-diode and a secondary coil of the transformer is parallel to the main diode. The rate of a rise in voltage across the main switch when turned off is suppressed by the rate of charging of the capacitor. Subsequently, by turning on the sub-switch, the current flowing through the main diode to be delivered to the transformer, thereby causing the current flowing through the main switch when turned on to be decreased by the sub-inductor.

Abstract: An electric power conversion device includes a power conversion circuit for receiving electric power from an overhead wire through an LC filter circuit composed of a reactor and a capacitor and converting the electric power to output and a control unit for controlling the power conversion circuit, wherein the control unit is provided with a delay unit for delaying the voltage across the capacitor so as to produce a first control signal, produces a second output voltage instruction from the first control signal and a first output voltage instruction specifying the magnitude of the output voltage of the converted power, and controls the power conversion circuit based on the second output voltage instruction.

Abstract: An apparatus and a system include a multiplier circuit for receiving a sensed voltage and current of a of a load resistance coupled to a rectified voltage from a transformer's output whose input is from a DC-to-AC converter being supplied from a DC power generator having an internal resistance. The multiplier outputs a product of the sensed voltage and current. A differentiator circuit outputs a rate of change of the product. An integrator circuit outputs an integrated voltage indicating an accumulative rate of change of the product. A voltage-to-frequency converter circuit generates a voltage waveform having a frequency determined by the integrated voltage. A driver circuit uses the voltage waveform to output a control signal for controlling a frequency of the DC-to-AC power converter where the apparatus substantially matches an input resistance of the transformer to the internal resistance, thereby maximizing power transfer to the load resistance.

Abstract: A method and apparatus for power conversion. In one embodiment, the method comprises operating an inverter in bursts by (i) enabling power production by the inverter during a first plurality of periods, and (ii) disabling power production by the inverter during a second plurality of periods.

Abstract: In a preferred embodiment, a voltage inverter comprises a voltage converter circuit and a controller. The voltage inverter produces a time-varying output voltage from an input voltage, which can be a DC input voltage or an AC input voltage. The controller provides a control signal at a duty ratio determined dynamically by a set of signals. The set of signals include the time-varying output voltage, a predetermined output voltage, a gain factor and an inductor current in the voltage converter circuit. The predetermined output voltage can have an AC waveform or an arbitrary time-varying waveform. The voltage inverter operates to match the time-varying output voltage to the predetermined output voltage. Input-output linearization is used to design a buck inverter, and input-output linearization with leading edge modulation is used to design boost and buck-boost inverters under conditions where left half plane zero effects are present.

Abstract: A power supply unit includes a switching power converter responsive to a control signal to switch a power switch thereof to provide an output voltage and an output current for a load. To reduce light-load or no-load power consumption of the power supply unit, the power supply unit repeats a process of stopping switching the power switch and recovering switching the power switch for a period of time once the output voltage decreases to be lower than a reference voltage.

Abstract: We describe a photovoltaic (PV) panel system comprising a PV panel with multiple sub-strings of connected solar cells in combination with a power conditioning unit (microinverter). The power conditioning unit comprises a set of input power converters, one connected to each sub-string, and a common output power conversion stage, to provide power to an ac mains power supply output. Integration of the micro-inverter into the solar PV module in this way provides many advantages, including greater efficiency and reliability. Additionally, embodiments of the invention avoid the need for bypass diodes, a component with a high failure rate in PV panels, providing lower power loss and higher reliability.

Abstract: A single-phase voltage source DC-AC power converter includes (a) a single-phase voltage source DC-AC power converting circuit having a gate signal generator that detects a single-phase AC output current at an AC terminal and that generates gate signals for making values of a PWM command and the single-phase AC output current identical, and (b) target current producing means that produces the PWM command such that a DC component included in the single-phase AC output voltage at the AC terminal becomes zero.

Abstract: Embodiments of the invention can provide systems, methods, and apparatus for converting direct current (DC) power to alternating current (AC) power. According to one embodiment, a system for converting DC power to AC power can be provided. The system can include a DC power source that provides a first DC power signal to a converter. Coupled to the converter can be a controller for transforming the first DC power signal into a plurality of AC power signals. The controller can also phase shift at least one of the plurality of AC power signals and combine the phase shifted AC power signal with at least one of the other of the plurality of AC power signals to provide a second DC power signal. The controller can also convert the second DC power signal to an AC power signal.

Abstract: A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal and an oscillation signal. A waveform generator generates a waveform signal in response to the oscillation signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a switching signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to a second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal.

Abstract: System and method for regulating an output voltage of a power conversion system. The system includes an error amplifier coupled to a capacitor. The error amplifier is configured to receive a reference voltage, a first voltage, and an adjustment current and to generate a compensation voltage with the capacitor. The first voltage is associated with a feedback voltage. Additionally, the system includes a current generator configured to receive the compensation voltage and generate the adjustment current and a first current, and a signal generator configured to receive the first current and a second current. The signal generator is further configured to receive a sensing voltage and to generate a modulation signal. Moreover, the system includes the gate driver directly or indirectly coupled to the signal generator and configured to generate a drive signal based on at least information associated with the modulation signal.

Abstract: A device for converting power from a floating source of DC power to a dual direct current (DC) output, the device includes: positive and negative input terminals connectible to the floating source of DC power; and positive and negative, and ground output terminals connectible to the dual DC output that may feed an inverter. The inverter may be either a two or three level inverter. A charge storage device may be connected in parallel to, and charged from, the positive and negative input terminals. A resonant circuit may be also connected between the charge storage device and the dual DC output. The resonant circuit may include an inductor connected in series with a capacitor. The charge storage device may discharge through the resonant circuit by switching through to either the negative output terminal or the positive output terminal.

Abstract: Embodiments of the invention provide an off line DC-DC converter comprising a transformer (180) coupled to a monolithic integrated circuit (400). The transformer applies an input supply DC voltage (Vin) applied to a primary winding (181) of the transformer to produce an output supply DC voltage provided from a secondary winding (182). The monolithic integrated circuit (400) comprises a switching regulator including a switch (151) and a switch controller (100) on a first portion of the monolithic integrated circuit. A capacitive isolator (201) is provided on a second portion of the monolithic integrated circuit. The monolithic integrated circuit regulates the output supply DC voltage and isolates the output supply DC voltage from the input supply DC voltage with respect to electrical shock hazard.

Abstract: A method of controlling a multilevel inverter of NPC (Neutral Point Clamped) type. The method includes regulating the electrical potential of the mid-point when the inverter operates at full voltage, that is to say in overmodulation. In this case, the method firstly determines the position of the control voltage vector in one of the six identical triangles covering the hexagonal vector space and thereafter decomposes the control voltage vector in the triangle by taking account of control combinations, defined in this triangle, for the switching arms.

Abstract: In a semiconductor module, a high-potential side conductor includes a wide section on which the high-potential side switching element is mounted, a high-potential side terminal coupled with a high potential source, and a narrow section extending from the wide section to the high-potential side terminal in a first direction. The wide section is wider than the narrow section in a second direction perpendicular to the first direction. The wide section has a first side and a second side opposite to the first side in the second direction. A distance between the first side of the wide section and a low-potential side conductor is shorter than a distance between the second side of the wide section and the low-potential side conductor. The narrow section extends from a portion of the wide section closer to the first side than the second side.

Abstract: A system and method for reducing reactive current in burn-in test systems for solar power converters is disclosed. An emulator configured to simulate a DC power source and the power converter subject to the burn-in test can be coupled in a two-unit circulating configuration. An AC feeder line configured to supply power to the two-unit circulating configuration. A controller can be configured to adjust the output of one or more of the emulator and power converter to reduce reactive current flowing in the AC feeder line. For instance, the controller can adjust the modulation of switching devices used in the power converter or emulator to adjust the power factor of various components of the burn-in test system to compensate for the reactive current in the AC feeder line.

Abstract: Low voltage ride through systems, methods, and apparatus are disclosed. An exemplary method includes applying real power from a photovoltaic array to an AC grid with an inverter, detecting a sag in the voltage in the AC grid, and responsive to the sag in the voltage in the AC grid, power from the photovoltaic array is utilized to provide power to at least one inverter-related component. When the sag in the voltage has abated, real power from the photovoltaic array is applied once again to the AC grid.

Abstract: A power isolation system and method is disclosed. The system includes a transformer suitable for use in the power isolation system, and a semiconductor device electrically connected to the transformer to provide a reduction of the inrush current associated with powering the transformer, wherein the semiconductor device is activated upon power up based upon the previous shutdown state of the power isolation system to provide a soft start to the transformer, and after activation of the transformer, the semiconductor device is shorted in the system.

Abstract: A voltage source converter station including a multilevel voltage source converter, for conversion of electrical power between AC and DC, and a control system. The voltage source converter includes a plurality of switching cells including switchable semiconductors, and the control system includes at least one main control unit for providing a voltage reference signal and a plurality of cell control units. Each cell control unit uses carrier based pulse width modulation for controlling the switching of a respective cell, where the main control unit is communicatively connected to the cell control units and provides the reference voltage signal to each cell control unit and each cell control unit creates a switching signal to each respective switching cell using the reference voltage signal and a carrier signal to effectuate the conversion.

Abstract: According to one embodiment, a system includes a battery to charge power and discharge a direct-current power to a converter, the converter supplying the converted power to a power system, detectors detecting a voltage at a point between the converter and power system, a current output from the converter and effective power from the voltage value and a current value detected, units computing an angular frequency of the voltage output from the converter, based on an effective power value and an output target value of effective power and an output voltage target value of the converter, based on a current value, a set voltage value and an angular frequency, and a controller controlling the converter according to the output voltage target value.

Abstract: The present invention relates to a voltage converter, a voltage converting method, a power adjuster, a power adjusting method, a photovoltaic system, and a management device which are capable of generating power with a higher output. In a photovoltaic system 11, each of the output converters 21-1 to 21-8, which converts a voltage of power generated by each of solar battery modules 22-1 to 22-8 to a voltage to be outputted to the outside, is provided with respect to each of the solar battery modules 22-1 to 22-8. In each of the output converters 21-1 to 21-8, an operation of a DC/DC converting part that executes a process for converting the voltage is switched to either conversion-rate fixing or maximum power point tracking control based on an amount of output power of the DC/DC converting part. The present invention is, for example, applicable to a photovoltaic system provided with an output converter with respect to each of solar battery modules.

Abstract: A power converter system includes a converter configured to be coupled to a power generation unit for receiving power from the power generation unit, and a bus coupled to the converter, wherein a voltage is generated across the bus when electricity is conducted through the power converter system. The power converter system also includes an inverter coupled to the bus and configured to supply power to an electrical distribution network, and a control system coupled to the converter and to the inverter. The control system is configured to gradually adjust the voltage across the bus during at least one of a shutdown sequence and a startup sequence of the power converter system.

Abstract: A controller that controls a switching element of an inverter using pulse width modulation is applied to a power converter including an inverter, to realize a stable change of a carrier frequency, current control responsiveness, and inverter loss suppression. The controller includes a carrier-frequency setting unit that sets a carrier frequency command used for pulse width modulation of an inverter corresponding to a current command and a current-command change rate. The carrier-frequency setting unit includes a carrier frequency map having mapped thereon information of a carrier frequency corresponding to a current command expressed in a vertical axis and a current-command change rate expressed in a lateral axis, and outputs information of a carrier frequency on the carrier frequency map corresponding to the input current command and the input current-command change rate to a switching pattern calculator.

Abstract: We describe a photovoltaic power conditioning unit comprising: both dc and ac power inputs; a dc link; at least one dc-to-dc converter coupled between dc input and dc link; and a dc-to-ac converter coupled between dc link and ac output. The dc-to-dc converter comprises: a transformer having input and output windings; an input dc-to-ac converter coupled between dc input and input winding; and an ac-to-dc converter coupled between output winding the dc link. The output winding has a winding tap between the first and second portions. The ac-to-dc converter comprises: first and second rectifiers, each connected to a respective first and second portion of the output winding, to the dc link and winding tap; and a series inductor connected to the winding tap. Rectifiers are connected to the winding tap of the output winding via the series inductor wherein the series inductor is shared between the first and second rectifiers.

Abstract: There is provided an apparatus and method for controlling a switch of a flyback converter for a solar generating system. The apparatus for controlling a switch of a flyback converter for a solar generating system includes: an MPPT controller generating a current command value for a maximum power point tracker of a solar cell module, based on input voltage, input current, and output voltage of the flyback converter; a current controller generating a current control signal for tracking the current command value; an output current command value generator generating the phase and magnitude command value of the output current, based on the phase of the output voltage and the current control signal; and a switch controller controlling the main switch of the flyback converter, based on the phase and magnitude command value of the output current, thereby simplifying a circuit while solving disadvantages of a discontinuous conduction mode and a boundary conduction mode.

Abstract: Power supplies, power adapters, and related methods are disclosed. One example power supply includes an open loop DC to DC converter having an input for connecting to an input power source and an output for supplying a DC output voltage or current and an enable/disable circuit coupled to the open loop DC to DC converter. The enable/disable circuit is configured to enable and disable the open loop DC to DC converter as a function of the DC output voltage or current. One example method includes determining a DC output voltage or current from an open loop DC to DC converter and enabling and disabling the open loop DC to DC converter as a function of the determined DC output voltage or current.

Abstract: An exemplary embodiment of the present disclosure includes a medium voltage inverter control apparatus and a medium voltage inverter system using the same. The medium voltage inverter control apparatus determines input voltage information by receiving an input voltage of a medium voltage inverter, compares an output command of the medium voltage inverter with an output of a first PLL unit to output a difference therebetween, and synchronizes the output command of the medium voltage inverter using the difference.

Abstract: A two-level or multi-level inverter are supplied with a positive auxiliary voltage (Ug+) and a negative auxiliary voltage (Ug?). A bootstrap technique provides a first positive auxiliary voltage and a first negative auxiliary voltage from the supplied potentials. The bootstrap technique provides at least one additional negative auxiliary voltage to a switch driver of at least one semiconductor switch from the first negative auxiliary voltage. At the start up of an inverter, the inverter can perform a startup sequence to provide auxiliary voltages to the respective auxiliary voltage inputs of the switch drivers by turning the power semiconductors sequentially on and off.

Abstract: A power conversion device includes a DC-DC converter, a DC-AC inverter and a relay. The DC-DC converter leads in a DC from an external solar panel and transforms the DC into a direct voltage. The DC-AC inverter transforms the direct voltage from the DC-DC converter into an alternating voltage and connecting to an external electric load via electric load output ends. The relay includes a coil connected to an external commercial power line via commercial power input ends, and conductive contacts actuated by the coil and serially-disposed between the commercial power input ends and the DC-AC inverter, and with the commercial power line electrifying the coils, the conduction control is formed therebetween, preventing the electric energy of the solar energy generation from inversely transmitting to the commercial power line when interrupting the commercial power service.

Abstract: A method for grid support by means of an inverter is disclosed, wherein the grid is supported by feeding in compensation currents. The method includes measuring a prevailing grid state, and breaking down voltages measured for measuring the prevailing grid state into symmetrical components of the grid state including positive sequence system components and negative sequence system components.