A method, a control circuit, and a power converter arrangement are disclosed. The method includes: coupling three power converters (1, 2, 3) with each other; connecting each of the three power converters (1, 2, 3) to a 3-phase power source (4) configured to provide three supply voltages (Ua, Ub, Uc); and regulating a respective input signal (V1, V2, V3; I1, I2, I3) of each of the three power converters (1, 2, 3) dependent on a common mode signal (Scm).

Embodiments of this application provide an alternating current power supply circuit, a control method for an alternating current power supply circuit. The alternating current power supply circuit includes a rectifier module and an inverter module. The rectifier module includes a first inductor L1, a first branch, a second branch, a third branch, a first capacitor, and a second capacitor, the third branch includes a soft switching cell, the soft switching cell includes a first switching component and a second switching component that are reversely connected in series, and the first branch, the second branch, and the third branch form an I-type three-level topology or a T-type three-level topology. The inverter module includes a second inductor L1, a fourth branch, a fifth branch, a sixth branch, the first capacitor, and the second capacitor, the sixth branch includes the soft switching cell, and the fourth branch, the fifth branch.

According to a non-isolated DCDC resonant conversion control circuit provided in embodiments of this application, an inductor and a capacitor that are resonant are connected in series, so that a current flowing through the inductor is a sine waveform. A waveform coefficient of the sine wave is small, and a conduction loss of the sine wave is low. Therefore, the circuit provided in embodiments of this application can significantly reduce a circuit loss. According to the non-isolated DCDC resonant conversion control method provided in embodiments of this application, not only a phase shift angle can be adjusted to enable a switching transistor to implement zero voltage switching (ZVS) on, but switching frequency can also be adjusted. Therefore, ranges in which a voltage and power of an output interface can be adjusted are large, so that non-isolated wide-range DCDC resonant conversion is implemented.

The resonant tank circuit (102) comprises: a transformer (T); a primary circuit (M1); and a secondary circuit (M2); wherein the transformer (T) and the primary and secondary circuits (M1, M2) are designed to operate in a forward mode and in a reverse mode; and wherein the transformer (T) and the primary and secondary circuits (M1, M2) have, at a resonant frequency (F.sub.R), a forward gain (G.sub.F(F.sub.R)), respectively a reverse gain (G.sub.R (F.sub.R)), essentially independent of the load, when operating in the forward mode, respectively the reverse mode. The primary and secondary circuits (M1, M2) are different one from another and the forward gain (G.sub.F(F.sub.R)) and the reverse gain (G.sub.R(F.sub.R)) at the resonant frequency (F.sub.R) are essentially equal to one another, notably to within 5%.

A method controls a converter assembly which has a line-commutated converter. The line-commutated converter has an alternating voltage terminal which can be connected via a phase conductor to an alternating voltage network. The converter assembly further has a switch module branch which is arranged serially in the phase conductor and which contains a series circuit of switch modules at each of the terminals of which bipolar voltages can be generated which add up to a branch voltage. A connection voltage to a connection point between the switch module branch and the converter is controlled by adjusting an amplitude of a positive sequence component of the branch voltage. The converter assembly is configured to carry out a control method for controlling the converter assembly.

In one embodiment, a method of operating a power electronic converter device for an electrical power converter system is provided. The power electronic converter device includes a converter circuit, a first converter, and a second converter. The first converter and the second converter are switch with a switching pattern such that the first converter and the second converter generate voltages with stepwise voltages changes and an output voltage of the power electronic converter device results frum a superposition of the voltages of the first converter and the second converter. The switching pattern includes switching instants for the second converter such that the voltage of the second converter leaves the fundamental voltage component of the voltage of the first converter unchanged, such that the second converter does not generate a fundamental component of the output voltage.

To allow reliable current measurement of the output current of the switching stage of an inverter, especially at switching frequencies of the semiconductor switches in the 100 kHz range, a voltage at the choke is measured and integrated over time to be representative for the leg current in the choke. The time integral is processed in a processing unit, whereas the processed time integral is used in an inverter controller for controlling the inverter. The voltage at the choke is analogously integrated over time by two serially connected integrator capacitors, whereas across each of the integrator capacitors a reset switch is provided, for alternately resetting the corresponding integrator capacitor.

A power conversion device includes, for respective phases of an AC circuit, leg circuits each having a pair of arms connected in series to each other, each arm including a plurality of converter cells which are connected in series and each of which has an energy storage element. A controlling circuitry includes a zero-phase-sequence voltage command value adjustment unit for correcting arm voltage command values for the arms by a zero-phase-sequence voltage command value. The command value correction circuitry performs adjustment control for adjusting the zero-phase-sequence voltage command value so that at least one arm voltage command value becomes equivalent to a limit value of the output voltage range of the arm.

A method and related apparatus for extending a DC voltage range of a rectifier circuit for the supply, from an AC grid, of a DC load which is connected to a DC rectifier output of the rectifier circuit, wherein an AC rectifier input of the rectifier circuit is connected via a grid connection point to the AC grid, wherein the rectifier circuit includes an AC/DC converter having an AC input and a DC output, wherein the AC/DC converter includes a converter circuit having semiconductor switches and freewheeling diodes connected in an antiparallel arrangement thereto, wherein an inductance is connected between the AC input of the AC/DC converter and the grid connection point. The method includes setting a desired DC operating voltage U.sub.DOC,soll on the DC output of the AC/DC converter or on the DC rectifier output, or both, by an actuation of semiconductor switches of the AC/DC converter, wherein, when the desired DC operating voltage U.sub.DC,soll lies below a value of an amplitude .Math..sub.4 of an alternating voltage on the AC input of the AC/DC converter, the semiconductor switches of the AC/DC converter are actuated for an exchange of reactive power Q.sub.1(t) with the AC grid, which has a voltage-lowering effect upon the amplitude .Math..sub.4 of the AC voltage at the AC input of the AC/DC converter, such that the amplitude .Math..sub.4 approaches the desired DC operating voltage U.sub.DC,soll, and wherein the exchange of the reactive power Q.sub.1(t) with the AC grid is executed during or shortly before an electrical connection or an electrical isolation of the DC load to or from the rectifier circuit.

In a switching power supply device, a comparison voltage is generated based on a feedback voltage commensurate with the output voltage. Synchronously with the output transistor being turned on, a ramp voltage is made to start increasing from a first initial voltage; when the ramp voltage exceeds the comparison voltage, the output transistor is turned off. When the switching frequency is lowered from a first frequency to a second frequency, it is switched to the second frequency after the lapse of a transition period. During the transition period, the ramp voltage is made to start increasing from a second initial voltage (>first initial voltage).