Abstract: A method and a system for controlling parallel-connected frequency converters or inverter units feeding an alternating-current motor (MOTOR1) provided with parallel windings or separate parallel motors having their shafts mechanically coupled together via a load, in which method the current supplied to the motor is measured. The frequency converters/inverter units are connected to each other via a data bus, e.g. a fast serial bus, and one of the frequency converters/inverter units (FCON1 or INU1) functions as a master device in such manner that it sends to the other device/devices (FCON2 or INU2) information over the data bus regarding the instantaneous value of the current (IW1) fed by it to the motor, said other devices functioning as follower devices so that they adjust their own current (IW2) on the basis of the current of the master device.

Abstract: Method of controlling a voltage controlled PWM (Pulse Width Modulated) frequency converter comprising a single phase rectifier bridge (10) connectable to a sinusoidal single phase supply, a DC intermediate circuit (11) and a controlled inverter bridge (12) for generating an AC output voltage with varying amplitude and frequency to a load, said inverter bridge (12) having PWM controlled semiconductor switches (V11–V16) and flywheel diodes (D11–D16) connected in inverse-parallel with the semiconductor switches, wherein the DC intermediate circuit (11) is provided with a DC capacitor unit, and wherein the frequency converter is controlled so that the supply line current (Iin) is essentially sinusoidal and in phase with the supply line voltage (Uin).

Abstract: A fixing and protecting arrangement for a capacitor may include a cooling element, one or more recesses arranged in the cooling element, and a capacitor intended to be fixed into each recess. The capacitor may be arranged in the recess in such a way that a lower surface of the capacitor is in contact with the cooling element for transferring heat from the capacitor to the cooling element.

Abstract: The invention relates to a cooling arrangement for an adjustable electric drive. The arrangement is arranged to conduct heat generated in electric devices by means of a liquid flowing through the cooling element to the surrounding space. The arrangement comprises a cooling element which is made of aluminum and to which components to be cooled can be fastened, and a base having means for fastening the cooling element. The arrangement is characterized in that the base is made of an aluminum profile that is stiffened and has mounting rails for receiving the cooling element and for preventing the movement of the cooling element transversely to the longitudinal direction of the mounting rails, and the cooling element can be fastened perpendicular to the profile base by using fastening means that support the cooling element so that components can be fastened to the cooling element, whereby the combined base and cooling element serve as a heat-conducting support base of the frequency converter.

Abstract: The invention relates to a cooling arrangement in a frequency converter, the arrangement being configured to convey heat generated at the frequency converter to a space surrounding the frequency converter, comprising a power part (10) of the frequency converter, a control part (20) and cooling means, comprising a cooling motor (31) and a transfer means (32) for producing cooling. In accordance with the invention, a cooling frequency converter is arranged in connection with the frequency converter to control the cooling means. The power part of the cooling frequency converter comprises a rectifier (11) of the frequency converter, an intermediate circuit (12) of the frequency converter as well as a unique power unit (43) of the cooling frequency converter.

Abstract: A fixing and protecting arrangement for a capacitor may include a cooling element, one or more recesses arranged in the cooling element, and a capacitor intended to be fixed into each recess. The capacitor may be arranged in the recess in such a way that a lower surface of the capacitor is in contact with the cooling element for transferring heat from the capacitor to the cooling element.

Abstract: The present invention relates to a fixing and protecting arrangement for a capacitor. The arrangement comprises a cooling element, one or more recesses arranged in the cooling element, and a capacitor intended to be fixed into each recess. The arrangement is characterized in that it comprises one or more recesses arranged in the cooling element, in which recess the capacitor is intended to be arranged in such a way that the lower surface of the capacitor is in contact with the cooling element for transferring heat from the capacitor to the cooling element.

Abstract: A method for the synchronization of parallel-connected inverter units (INU1, INU2) or frequency converters and an inverter apparatus or a frequency converter apparatus wherein the inverter units are provided with inverter-specific modulators, in which method the circulating current between the inverter units is measured, and the modulators are synchronized to each other on the basis of the current measurement data.

Abstract: A method and an apparatus for charging a filtering capacitor in the direct-voltage intermediate circuit of a voltage-controlled PWM frequency converter comprising a rectifier (20) connected to an alternating-current source (UR, US, UT), a direct-voltage intermediate circuit and an inverter unit (11)/inverter units for feeding a multi-phase alternating voltage (UU, UV, UW) of variable frequency into a load/loads (12), said rectifier bridge having controlled semiconductor switches (V1-V3), especially thyristors, in one arm, preferably in the upper arm, and diodes (D1-D6) in the other arm, preferably the lower arm, and said direct-voltage intermediate circuit being provided with a capacitor unit (CDC) of a relatively high capacitance for filtering the voltage.

Abstract: The invention relates to a fastening device for fastening a toroidal choking coil (1) to a base or the like, the toroidal choking coil comprising an inner circumference defined by a surface parallel with an axis of rotation of the toroidal choking coil and located closest to the axis of rotation. The toroidal choking coil further comprises an outer circumference defined by a surface parallel with the axis of rotation of the toroidal choking coil and located outermost from the axis of rotation, and side surfaces defined by surfaces perpendicular to the axis of rotation of the toroidal choking coil and connecting the inner circumference and the outer circumference.

Abstract: A method and an apparatus for compensating reactive power and/or harmonic currents in an alternating-current network by means of a frequency converter (1) feeding an alternating-current load (3), which frequency converter has a mains bridge (10) and at least one load bridge (11), said bridges being provided with controllable semiconductor switches. In the method, the reactive power and/or harmonic currents in the alternating-current network are measured, the load of the mains bridge of the frequency converter is measured, and the reactive power and/or harmonic currents in the alternating-current network are compensated by means of the frequency converter when the mains bridge is running at less than full capacity or has no load.

Abstract: The invention relates to a fastening device for a toroidal choking coil for fastening a toroidal coil (1) to an electric device or a corresponding supporting base (13), the toroidal choking coil comprising an inner circumference defined by a surface parallel with an axis of rotation of the toroidal choking coil (1) and located closest to the axis of rotation, an outer circumference defined by a surface parallel with the axis of rotation of the toroidal choking coil (1) and located outermost from the axis of rotation, and side surfaces defined by surfaces perpendicular to the axis of rotation of the toroidal choking coil (1) and connecting the inner circumference and the outer circumference.

Abstract: A space-vector pulse-width modulation method for a frequency converter provided with a voltage intermediate circuit, said frequency converter comprising a mains bridge (10) to be connected to an alternating current source (UU, UV, UW), a direct-voltage intermediate circuit and a controlled load bridge (11) for supplying a variable-frequency alternating voltage (US, UR, UT) to a load (12), and in which method the modulator performing the modulation is given a reference. The load bridge modulator is given a reference consisting of the references for the flux linkage changes produced by the voltage vectors, the flux linkage change is calculated on the basis of measured intermediate-circuit voltage, and the currently active voltage vector is kept turned on until the reference value is reached.

Abstract: The invention relates to a liquid cooling element for cooling heat generating elements of frequency converters, in particular, and an arrangement for connecting the liquid cooling element. The liquid cooling element 2 is provided with two channel systems: horizontal channels 3, 4 and transverse channels 5 connecting said horizontal channels. The liquid cooling element 2 is characterized by consisting of one integral piece, the transverse channels 5 being arranged eccentrically to the horizontal channels 3, 4 such that the longitudinal axis of the transverse channel 5 is closer to the lateral face of the cooling element than the longitudinal axis of the horizontal channel 3, 4 and the outer edge of the transverse channel 5 extends closer to the lateral face of the cooling element than the outer edge of the horizontal channel 3, 4.

Abstract: The invention relates to a cooling arrangement for an adjustable electric drive. The arrangement is arranged to conduct heat generated in electric devices by means of a liquid flowing through the cooling element to the surrounding space. The arrangement comprises a cooling element which is made of aluminum and to which components to be cooled can be fastened, and a base having means for fastening the cooling element. The arrangement is characterized in that the base is made of an aluminum profile that is stiffened and has mounting rails for receiving the cooling element and for preventing the movement of the cooling element transversely to the longitudinal direction of the mounting rails, and the cooling element can be fastened perpendicular to the profile base by using fastening means that support the cooling element so that components can be fastened to the cooling element, whereby the combined base and cooling element serve as a heat-conducting support base of the frequency converter.

Abstract: The present invention relates to a fixing and protecting arrangement for a capacitor. The arrangement comprises a cooling element, one or more recesses arranged in the cooling element, and a capacitor intended to be fixed into each recess. The arrangement is characterized in that it comprises one or more recesses arranged in the cooling element, in which recess the capacitor is intended to be arranged in such a way that the lower surface of the capacitor is in contact with the cooling element for transferring heat from the capacitor to the cooling element.

Abstract: An inverter control unit having a bridge circuit provided with controllable semiconductor switches in upper and lower circuit arms, which bridge circuit converts a direct voltage to be fed to the inverter into an alternating voltage of variable frequency and amplitude, said control unit controlling the semiconductor switches by pulse-width modulation (PWM) to generate an inverter output voltage, and said control unit comprising a first control section (21) at ground potential and a second control section (22) at the potential of the semiconductor switches, galvanically isolated channels being provided between said sections for serial transmission of control data from the first control section to the second control section and of feedback data from the second control section to the first control section.

Abstract: The invention relates to a shielding arrangement in a connector and to a connector enabling the use of the arrangement for connecting at least two electric conductors in a shielded manner. The connector comprises a body arranged to attach to a base. In addition, the connector has a receiving element for electrically connecting an entering electric conductor and an exiting electric conductor, said receiving element being arranged to attach to the body. A cavity open on one side is arranged to the body of the connector of the invention, the cavity being arranged to have a size suitable for receiving a shielding means in such a manner that, when the body is attached to its base, the body covers at least partly said shielding means.

Abstract: The invention relates to a shielding arrangement in a connector and to a connector enabling the use of the arrangement for connecting at least two electric conductors in a shielded manner. The connector comprises a body arranged to attach to a base. In addition, the connector has a receiving element for electrically connecting an entering electric conductor and an exiting electric conductor, said receiving element being arranged to attach to the body. A cavity open on one side is arranged to the body of the connector of the invention, the cavity being arranged to have a size suitable for receiving a shielding means in such a manner that, when the body is attached to its base, the body covers at least partly said shielding means.

Abstract: The invention relates to a cooling arrangement in a frequency converter, the arrangement being configured to convey heat generated at the frequency converter to a space surrounding the frequency converter, comprising a power part (10) of the frequency converter, a control part (20) and cooling means, comprising a cooling motor (31) and a transfer means (32) for producing cooling. In accordance with the invention, a cooling frequency converter is arranged in connection with the frequency converter to control the cooling means. The power part of the cooling frequency converter comprises a rectifier (11) of the frequency converter, an intermediate circuit (12) of the frequency converter as well as a unique power unit (43) of the cooling frequency converter.