A frequency converter includes: a primary winding 12 in which a plurality of windings on which a polyphase alternating voltage is applied are arranged periodically along a particular direction; a secondary winding 22 which is magnetically coupled to the primary winding 12 and in which a plurality of windings are arranged along the particular direction with a repetition period different from the primary winding 12; and a frequency modulation part 3 which is arranged on a magnetic path between the primary winding 12 and the secondary winding 22 and in which a plurality of magnetic materials 31 are arranged periodically. Then, the pitch of the plurality of magnetic materials 31 and the winding arrangement period of the primary winding 12 and the secondary winding 22 are different from each other so that an alternating voltage having a frequency different from the frequency of the polyphase alternating voltage is induced in the secondary winding 22.

A trans-impedance amplifier that converts a current signal output by a light-receiving element into a voltage signal has a conversion gain that is variable. A gain control circuit detects a bottom voltage with respect to the voltage signal output by the trans-impedance amplifier and controls the conversion gain of the trans-impedance amplifier based on the detection results. A convergence determination circuit determines whether the control of gain is in a convergent state or a non-convergent and outputs to the gain control circuit a determination signal indicating the determination results. When the determination signal indicates a transition from the non-convergent state to the convergent state, the convergence control circuit maintains a value of the conversion gain at a time of the transition.

A trans-impedance amplifier that converts a current signal output by a light-receiving element into a voltage signal has a conversion gain that is variable. A gain control circuit detects a bottom voltage with respect to the voltage signal output by the trans-impedance amplifier and controls the conversion gain of the trans-impedance amplifier based on the detection results. A convergence determination circuit determines whether the control of gain is in a convergent state or a non-convergent and outputs to the gain control circuit a determination signal indicating the determination results. When the determination signal indicates a transition from the non-convergent state to the convergent state, the convergence control circuit maintains a value of the conversion gain at a time of the transition.

A power converter can include an inverter including, connected in series, switching elements, the inverter circuit being connected to both ends of a DC power source series circuit resulting from connecting in series a DC power source and a DC power source. Also included can be an AC output terminal that is connected to a connection point of the switching element and the switching element, an AC output terminal that is connected to a connection point of the DC power source and the DC power source, a bidirectional switch element one end of which is connected to the AC output terminal and the other end of which is connected to a terminal of an AC power source and a bidirectional switch element one end of which is connected to the AC output terminal and the other end of which is connected to the AC power source.

A power converter can include an inverter including, connected in series, switching elements, the inverter circuit being connected to both ends of a DC power source series circuit resulting from connecting in series a DC power source and a DC power source. Also included can be an AC output terminal that is connected to a connection point of the switching element and the switching element, an AC output terminal that is connected to a connection point of the DC power source and the DC power source, a bidirectional switch element one end of which is connected to the AC output terminal and the other end of which is connected to a terminal of an AC power source and a bidirectional switch element one end of which is connected to the AC output terminal and the other end of which is connected to the AC power source.

A reconfigurable coupled inductor is disclosed. In one embodiment, the reconfigurable coupled inductor comprises metal rings and switches coupled to the metal rings to control at least one inductor property (e.g., coupling coefficient) based on a closed (e.g., on) or open state (e.g., off) of each switch.

A power conversion device able to supply a constant load voltage even when the voltage of a 3-phase alternating current power supply fluctuates. A series circuit formed of switching element Q1 and switching element Q2 and a series circuit formed of switching element Q3 and switching element Q4 are connected to both ends of direct current power supply series circuit 3 formed of direct current power supply Psp and direct current power supply Psn, a bidirectional switch element S1 is connected between alternating current output terminals U and R, a bidirectional switch element S2 is connected between alternating current output terminal U and neutral terminal O, a bidirectional switch element S3 is connected between alternating current output terminal W and neutral terminal O, a bidirectional switch element S4 is connected between alternating current output terminal W and terminal T, and alternating current output terminals V and terminal S are connected.

A power conversion device able to supply a constant load voltage even when the voltage of a 3-phase alternating current power supply fluctuates. A series circuit formed of switching element Q1 and switching element Q2 and a series circuit formed of switching element Q3 and switching element Q4 are connected to both ends of direct current power supply series circuit 3 formed of direct current power supply Psp and direct current power supply Psn, a bidirectional switch element S1 is connected between alternating current output terminals U and R, a bidirectional switch element S2 is connected between alternating current output terminal U and neutral terminal O, a bidirectional switch element S3 is connected between alternating current output terminal W and neutral terminal O, a bidirectional switch element S4 is connected between alternating current output terminal W and terminal T, and alternating current output terminals V and terminal S are connected.

Methods, systems, circuits, and devices for power-packet-switching power converters using bidirectional bipolar transistors (BTRANs) for switching. Four-terminal three-layer BTRANs provide substantially identical operation in either direction with forward voltages of less than a diode drop. BTRANs are fully symmetric merged double-base bidirectional bipolar opposite-faced devices which operate under conditions of high non-equilibrium carrier concentration, and which can have surprising synergies when used as bidirectional switches for power-packet-switching power converters. BTRANs are driven into a state of high carrier concentration, making the on-state voltage drop very low.

The present invention relates to a circuit arrangement for electrical installations for converting and adapting a DC voltage of a voltage source, more particularly for a solar inverter of a photovoltaic installation, having an electrical output, which can be coupled to an inverter, wherein, at the electrical output, a potential in a positive branch of an intermediate circuit of the electrical installation can be increased in such a way that an output potential of a negative pole of the voltage source assumes a value greater than the potential of the negative pole before the increase, or the potential in a negative branch of the intermediate circuit of the electrical installation can be reduced in such a way that an output potential of a positive pole of the voltage source assumes a value lower than the potential of the positive pole before the reduction, and having a compensation device designed for compensating for the electrical power between the positive branch of the intermediate circuit of the electrical installation and the negative branch of the intermediate circuit of the electrical installation during the operation of the circuit arrangement. The present invention furthermore relates to a method and a photovoltaic installation.