Abstract: A method for a direct current (DC) power distribution arrangement and a direct current (DC) power distribution arrangement, comprising a plurality of DC power distribution subsystems. Each DC power distribution subsystem comprises an inverter unit (INU) configured to operate as a subsystem-specific circuit breaker for intercoupling/separating the DC power distribution subsystem to/from the rest of the DC power distribution arrangement.

Abstract: A converter circuitry between a first network, which may be either a poly-phase medium-voltage alternating current (AC) network, at least one polyphase low-voltage AC network or at least one direct-current (DC) network, and a second network, which may be either a polyphase medium-voltage AC network or a medium-voltage DC network, wherein the converter circuitry comprises at least one power bus and low-voltage power cells both at the first and at the second network side such that each power cell is connected to a power bus via a transformer. Each power bus is connected to a low-voltage power unit, which is able to supply pre-charging power via the power bus to all power cell intermediate DC-link filtering capacitors before the converter is started. The low-voltage power unit is also able to take care of a resistor braking in case the first network cannot take the power supplied by the load connected to the second network.

Abstract: A converter circuitry between a first network, which may be either a poly-phase medium-voltage alternating current (AC) network, at least one polyphase low-voltage AC network or at least one direct-current (DC) network, and a second network, which may be either a polyphase medium-voltage AC network or a medium-voltage DC network, wherein the converter circuitry comprises at least one power bus and low-voltage power cells both at the first and at the second network side such that each power cell is connected to a power bus via a transformer. Each power bus is connected to a low-voltage power unit, which is able to supply pre-charging power via the power bus to all power cell intermediate DC-link filtering capacitors before the converter is started. The low-voltage power unit is also able to take care of a resistor braking in case the first network cannot take the power supplied by the load connected to the second network.

Abstract: Unique systems, methods, techniques and apparatuses of power amplifiers are disclosed. One exemplary embodiment is a power system for an active magnetic bearing including at least one power amplifier. Each power amplifier includes a first semiconductor device including a first node coupled to a neutral point node and a second node, a second output node coupled to the neutral point node, a second semiconductor device including a first node coupled to the second node of the first semiconductor device and a second node coupled to a first output node, a third semiconductor device including a first node coupled to a first DC bus node and a second node coupled to the first output node, and a fourth semiconductor device including a first node coupled to a second DC bus node and a second node coupled to the second node of the first semiconductor device.

Abstract: Unique systems, methods, techniques and apparatuses of active magnetic bearing control systems are disclosed. One exemplary embodiment is a power converter electrically coupled to an active magnetic bearing (AMB) having a plurality of windings, the power converter comprising a DC bus, two capacitors, a first leg, a second leg, and a controller. The capacitors are electrically coupled in series between the positive rail and negative rail, one capacitor being electrically coupled to the other capacitor at a midpoint connection. The first leg comprises a first semiconductor switching device and a first output node. The second leg comprises a second semiconductor switching device and a second output node. The first output node is electrically coupled to the midpoint connection by way of a first AMB winding and the second output node is electrically coupled to the midpoint connection by way of a second AMB winding.

Abstract: Unique systems, methods, techniques and apparatuses of active magnetic bearing control systems are disclosed. One exemplary embodiment is a power converter electrically coupled to an active magnetic bearing (AMB) having a plurality of windings, the power converter comprising a DC bus, two capacitors, a first leg, a second leg, and a controller. The capacitors are electrically coupled in series between the positive rail and negative rail, one capacitor being electrically coupled to the other capacitor at a midpoint connection. The first leg comprises a first semiconductor switching device and a first output node. The second leg comprises a second semiconductor switching device and a second output node. The first output node is electrically coupled to the midpoint connection by way of a first AMB winding and the second output node is electrically coupled to the midpoint connection by way of a second AMB winding.

Abstract: Unique systems, methods, techniques and apparatuses of power amplifiers are disclosed. One exemplary embodiment is a power system for an active magnetic bearing including at least one power amplifier. Each power amplifier includes a first semiconductor device including a first node coupled to a neutral point node and a second node, a second output node coupled to the neutral point node, a second semiconductor device including a first node coupled to the second node of the first semiconductor device and a second node coupled to a first output node, a third semiconductor device including a first node coupled to a first DC bus node and a second node coupled to the first output node, and a fourth semiconductor device including a first node coupled to a second DC bus node and a second node coupled to the second node of the first semiconductor device.

Abstract: A method for a direct current (DC) power distribution arrangement and a direct current (DC) power distribution arrangement, comprising a plurality of DC power distribution subsystems. Each DC power distribution subsystem comprises an inverter unit (INU) configured to operate as a subsystem-specific circuit breaker for intercoupling/separating the DC power distribution subsystem to/from the rest of the DC power distribution arrangement.

Abstract: Unique systems, methods, techniques and apparatuses of active magnetic bearing control systems are disclosed. One exemplary embodiment is a power converter electrically coupled to an active magnetic bearing (AMB) having a plurality of windings, the power converter comprising a DC bus, two capacitors, a first leg, a second leg, and a controller. The capacitors are electrically coupled in series between the positive rail and negative rail, one capacitor being electrically coupled to the other capacitor at a midpoint connection. The first leg comprises a first semiconductor switching device and a first output node. The second leg comprises a second semiconductor switching device and a second output node. The first output node is electrically coupled to the midpoint connection by way of a first AMB winding and the second output node is electrically coupled to the midpoint connection by way of a second AMB winding.

Abstract: The invention relates to a braking apparatus, an electric drive and an elevator system. The braking apparatus comprises an apparatus for dynamic braking, for braking an electric machine with dynamic braking, an input for the control signal of the braking apparatus, and also a controller, for controlling the apparatus for dynamic braking as a response to the aforementioned control signal of the braking apparatus.

Abstract: Apparatus for transferring power between an electricity network (UP) operating on alternating-current electricity and a multiphase electric machine (M2, M3), which apparatus comprises low-voltage power cells (CS, C11 . . . CN6) operating on a cascade principle, which power cells comprise a single-phase output connector (OUT), and at least one transformer (TA, T1 . . . TN), comprising for each power cell connected to it a single-phase or multiphase winding dedicated to the specific power cell, which transformer comprises at least one additional winding (WA, WB1 . . . WBN) connected to the same magnetic circuit as the other windings for the purpose of at least one auxiliary circuit, which can be connected to the aforementioned additional winding.

Abstract: Method and apparatus for controlling an apparatus transmitting power between two electricity networks or between an electricity network and a polyphase electric machine), and including low-voltage power cells (C), which include a single-phase input/output connection (IN/OUT). The power cells are arranged into groups (G1-GN, GP1-GPN1, GS1-GSN2, G1??-GN??) such that at least one power cell per each phase of the electricity network or of the electric machine belongs to each group, and the input terminals (IN) of all the power cells belonging to the same group are connected to a common transformer, the transformer including its own separate winding that is galvanically isolated. The controllable power semiconductor switches connected to the input connectors (IN) of all the power cells supplying power to the same transformer are controlled cophasally with a 50% pulse ratio.

Abstract: The invention relates to a braking apparatus, an electric drive and an elevator system. The braking apparatus comprises an apparatus for dynamic braking, for braking an electric machine with dynamic braking, an input for the control signal of the braking apparatus, and also a controller, for controlling the apparatus for dynamic braking as a response to the aforementioned control signal of the braking apparatus.

Abstract: Apparatus for transferring power between an electricity network (UP) operating on alternating-current electricity and a multiphase electric machine (M2, M3), which apparatus comprises low-voltage power cells (CS, C11 . . . CN6) operating on a cascade principle, which power cells comprise a single-phase output connector (OUT), and at least one transformer (TA, T1 . . . TN), comprising for each power cell connected to it a single-phase or multiphase winding dedicated to the specific power cell, which transformer comprises at least one additional winding (WA, WB1 . . . WBN) connected to the same magnetic circuit as the other windings for the purpose of at least one auxiliary circuit, which can be connected to the aforementioned additional winding.

Abstract: Method and apparatus for controlling an apparatus transmitting power between two electricity networks or between an electricity network and a polyphase electric machine (M/G), which electricity networks can be polyphase alternating-current networks or one of them can be a single-phase direct-current network, and which apparatus comprises low-voltage power cells (C), which comprise a single-phase output connection (OUT). The power cells also comprise a single-phase input connector (IN), the power cells are arranged into groups (G1-GN, GP1-GPN1, GS1-GSN2, G1??-GN??) such that at least one power cell per each phase of the electricity network or of the electric machine belongs to each group, and the input terminals (IN) of all the power cells belonging to the same group are connected to a common transformer, which transformer comprises its own separate winding that is galvanically isolated from the others for the power cell connected to it.

Abstract: A method and a corresponding appliance for measuring the output current of a frequency converter, the frequency converter including a network bridge that can be connected to an AC network, a controllable three-phase load bridge that can be connected to an AC load, and a DC intermediate circuit between them, the DC intermediate circuit including a filter capacitor that includes controllable semiconductor switches in each phase and that are controlled by pulse-width modulation, and in which the currents of the output phases are determined based on measured samples of the current of the filter capacitor of the DC intermediate circuit.

Abstract: A method and an apparatus for measuring the output currents of a frequency converter, preferably a vector-controlled frequency converter, which comprises a mains bridge (10) connectable to an alternating-current network and a load bridge (11) connectable to an alternating-current load and between these a direct-voltage intermediate circuit, by using current samples obtained from a current measuring sensor in the intermediate voltage circuit, wherein a sample is taken from the signal of the current measuring sensor substantially simultaneously with a point of change of the output voltage vector and upon the lapse of a predetermined delay after the point of change after the switching effects have settled.

Abstract: An arrangement and method for monitoring a frequency converter, the frequency converter being a voltage-controlled PWM frequency converter provided with a control unit and having an uncontrolled or a main-frequency controlled main bridge connectable to an alternating-current source (UL1, UL2, UL3), a direct-voltage intermediate circuit and a controlled load bridge for producing a variable-frequency multi-phase output voltage (UU, UV, UW), which direct-voltage intermediate circuit of the frequency converter is provided with a small-capacitance direct-voltage capacitor, the main bridge being connected to the load bridge directly without a large-capacitance direct-voltage capacitor functioning as an intermediate energy storage, and the arrangement includes a measuring unit for measuring the direct voltage of the intermediate voltage circuit.

Abstract: An overvoltage protection system for the intermediate circuit of frequency converter, said frequency converter being a voltage-controlled PWM-frequency converter comprising an uncontrolled mains bridge (10) to be connected to an alternating-current source (UL1, UL2, UL3), a direct-voltage intermediate circuit and a controlled load bridge (12) for producing a multi-phase alternating voltage (UU, UV, UW) of variable frequency, wherein the direct-voltage circuit of the frequency converter contains a low-capacitance direct-voltage capacitor, the mains bridge (10) being connected to the load bridge (12) directly without a high-capacitance direct-voltage capacitor serving as an intermediate energy storage, and which overvoltage protection system contains a varistor (R1).

Abstract: Method and appliance for measuring the output current of a frequency converter, which frequency converter contains a network bridge (10) that can be connected to an AC network, a controllable three-phase load bridge (11) that can be connected to an AC load, and a DC intermediate circuit between them, which contains a filter capacitor, which load bridge contains controllable semiconductor switches in each phase, which are controlled by pulse-width modulation, and in which the currents of the output phases are determined by means of measured samples of the current of the filter capacitor of the DC intermediate circuit.