Abstract: A filtering arrangement for a system including a power electronics device and an external power storage/discharge element, which power electronics device includes a power module and a three-phase filter between the AC power terminals of the power module and the supplying AC power grid, and which power module includes a DC intermediate power bus, and which three-phase filter between the AC power terminals and the supplying AC power grid includes two three-phase inductors, and which external power storage/discharge element has two DC power terminals which are connected to the DC intermediate power bus of the power electronics device. The filtering arrangement includes a common mode inductor which is connected between the DC power terminals of the external power storage/discharge element and the terminals of the DC intermediate power bus of the power module.

Abstract: A power electronic converter comprises controllable switches (104-109) and a control system (110) for operating the controllable switches. The control system is configured to control the controllable switches so as to produce at least one test voltage pulse. The power electronic converter comprises a voltage sensor (111) for detecting a reflected voltage that is caused by a reflection of the test voltage pulse in an electric system connected to the power electronic converter. The control system is configured to control the operation of the power electronic converter at least partly in accordance with information based on the detection of the reflected voltage. The information can be used for example for determining forbidden voltage pulse lengths which would cause reflection-based over-voltages and/or for detecting faults such as short circuits and earth faults.

Abstract: A filtering method and arrangement for a system comprising a regenerative frequency converter and a motor, which regenerative frequency converter has an intermediate DC circuit comprising positive and negative pole and which regenerative frequency converter is connected to a supplying 3-phase mains network via a line filter unit comprising in serial connection a first 3-phase inductor unit with mains side terminals and motor side terminals and a second 3-phase inductor unit, and a 3-phase capacitor unit which comprises phase-specific capacitors which are connected in star connection between the motor side terminals of the first 3-phase inductor unit and a star point, which star point is connected to ground via a fourth capacitor. The filtering arrangement further comprises a common mode inductor unit and a filtering capacitor unit.

Abstract: A power electronic converter comprises controllable switches (104-109) and a control system (110) for operating the controllable switches. The control system is configured to control the controllable switches so as to produce at least one test voltage pulse. The power electronic converter comprises a voltage sensor (111) for detecting a reflected voltage that is caused by a reflection of the test voltage pulse in an electric system connected to the power electronic converter. The control system is configured to control the operation of the power electronic converter at least partly in accordance with information based on the detection of the reflected voltage. The information can be used for example for determining forbidden voltage pulse lengths which would cause reflection-based over-voltages and/or for detecting faults such as short circuits and earth faults.

Abstract: A filtering method and arrangement for a system comprising a regenerative frequency converter and a motor, which regenerative frequency converter has an intermediate DC circuit comprising positive and negative pole and which regenerative frequency converter is connected to a supplying 3-phase mains network via a line filter unit comprising in serial connection a first 3-phase inductor unit with mains side terminals and motor side terminals and a second 3-phase inductor unit, and a 3-phase capacitor unit which comprises phase-specific capacitors which are connected in star connection between the motor side terminals of the first 3-phase inductor unit and a star point, which star point is connected to ground via a fourth capacitor. The filtering arrangement further comprises a common mode inductor unit and a filtering capacitor unit.

Abstract: A filtering arrangement for a system comprising a power electronics device and an external power storage/discharge element, which power electronics device comprises a power module and a three-phase filter between the AC power terminals of the power module and the supplying AC power grid, and which power module comprises a DC intermediate power bus, and which three-phase filter between the AC power terminals and the supplying AC power grid comprises two three-phase inductors, and which external power storage/discharge element has two DC power terminals which are connected to the DC intermediate power bus of the power electronics device. The filtering arrangement comprises a common mode inductor which is connected between the DC power terminals of the external power storage/discharge element and the terminals of the DC intermediate power bus of the power module.

Abstract: Three-phase AC or two-phase DC choke arrangement of a frequency converter, in which is a magnetic core, in which are the phase-specific pillars of the AC choke arrangement or the branch-specific pillars of the DC choke arrangement (1a, 1b), around which are arranged the phase-specific windings of the AC choke arrangement or the branch-specific windings of the DC choke arrangement (Ldc1+, Ldc1?) to filter difference-mode currents, and in which an additional pillar (3) for damping common-mode currents is arranged in the magnetic core of the choke. The additional pillar (3) is arranged without the phase-specific or branch-specific windings fitted around it, in which case damping of the common-mode currents is achieved by means of the common-mode impedance formed by the windings arranged around the additional pillar and around the phase-specific or the branch-specific pillars.

Abstract: A polyphase filtering choke arrangement of a power electronics appliance, more particularly of a frequency converter. which arrangement comprises two separate magnetic cores, around both of which a polyphase winding is arranged, particularly for filtering the harmonics of a network current and the common-mode noise currents, wherein both the magnetic cores (1, 2, 101a-101c, 102a-102c, 130a-130d, 140a-140d) are shaped to form a closed magnetic circuit, the magnetic cores (1 and 2, 101a-101c and 102a-102c, 130a-130d and 140a-140d) are arranged one on top of the other, the magnetic cores are connected to each other with connecting pieces (11-13, 11a-13b, 111-113, 121-124), and the winding directions of the windings of the magnetic cores are opposing with respect to each other, in which case the fluxes produced in the magnetic cores of each current are of opposing directions, in which case the flux produced by the difference-mode current circulates via the connecting pieces from one magnetic core to another.

Abstract: DC choke arrangement of a power transformer, especially of a frequency converter, provided with a DC circuit and connected to an AC electricity network, to limit the harmonics of the network current taken by an appliance from the AC network, in which DC choke arrangement is at least one choke (Ldc+, Ldc?), which is arranged in the magnetic core, which contains pillar parts and yoke parts (1a?, 1b?, 2a?, 2b?), in which one or more permanent magnets (51) are arranged in the magnetic core of the choke, and in which the permanent magnet is positioned at an angle with respect to the longitudinal direction of the part or parts of the magnetic core such that the cross-sectional area of the permanent magnet is greater than the cross-sectional area of the part of the magnetic core in question or the parts of the magnetic core in question.

Abstract: A wiring arrangement and an appliance for limiting the harmonics of a current supplied to a frequency converter from an AC electricity supply network, which frequency converter can be connected to a three-phase AC electricity supply network, in which frequency converter is an uncontrolled network bridge (10) for rectifying the AC voltage of the AC electricity supply network, a DC intermediate circuit, in which is a filtering capacitor (CDC), and a load bridge (11) provided with power semiconductor switches for forming three-phase AC voltage (U, V, W), and which load bridge can be controlled with pulse-width modulation by means of a control unit, and in which DC intermediate circuit is a choke, in which is a choke part (L1, L2) arranged on both the positive and the negative pole, and in which wiring arrangement is an absorption circuit for limiting the harmonics of the current supplied from the AC electricity supply network, in which the absorption circuit is arranged in the DC intermediate voltage circuit,

Abstract: Three-phase AC or two-phase DC choke arrangement of a frequency converter, in which is a magnetic core, in which are the phase-specific pillars of the AC choke arrangement or the branch-specific pillars of the DC choke arrangement (1a, 1b), around which are arranged the phase-specific windings of the AC choke arrangement or the branch-specific windings of the DC choke arrangement (Ldc1+, Ldc1?) to filter difference-mode currents, and in which an additional pillar (3) for damping common-mode currents is arranged in the magnetic core of the choke. The additional pillar (3) is arranged without the phase-specific or branch-specific windings fitted around it, in which case damping of the common-mode currents is achieved by means of the common-mode impedance formed by the windings arranged around the additional pillar and around the phase-specific or the branch-specific pillars.