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: 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: 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: 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: 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: A method of protecting a frequency converter against overvoltage by controlling an AC motor during braking or during light load and a frequency converter, wherein the frequency converter is a voltage-controlled PWM frequency converter operating in single quadrant (1Q) and comprising at least one uncontrolled rectifier bridge (10) to be connected to a AC supply line (UL1, UL2, UL3), a direct-voltage intermediate circuit and at least one controlled inverter bridge (11) for feeding an AC motor (12) with an alternating voltage (Uu, Uv, Uw) of varying magnitude and frequency, in which method: the angle (??) between the output voltage vector (Us) and current vector (Is), i.e. the power factor, is measured, the angle (??) between the output voltage vector (Us) and current vector (Is), i.e. the power factor, is controlled on the basis of the measurement, and the angle (??) between the output voltage vector (Us) and current vector (Is), i.e.

Abstract: A method and a system for measuring a quantity, such as current, of a power converter apparatus including parallel-connected power converter units. A component quantity, of each power converter unit is measured, transmitted digitally in serial communication format to a control unit (CU), and summed to produce a summed quantity. The component quantity data are transmitted to the control unit with the least significant bit (LSB) first. The summing is started as soon as the LSBs of the component quantities have been received. The LSB of the sum is transmitted further as soon as the LSBs of the component quantities have been summed. After this, the rest of the bits are summed in the order of arrival, with the most significant bit (MSB) last. The respective summing data are transmitted further in the order of arrival as soon as the corresponding bits of the component quantities have been summed.

Abstract: A method and a system for controlling the mains bridge of a four-quadrant PWM frequency converter provided with a direct-voltage intermediate circuit when power is flowing into the supply network. The mains bridge includes a controlled mains bridge (INU) for rectification of the mains voltage to produce a DC intermediate-circuit direct voltage (UDC) consisting of arms conducting during the positive and negative half cycles of the phase voltage of each phase of the supply network, each arm having a switch unit formed by a diode (D1–D6) and a power semiconductor switch (V1–V6), e.g. an IGBT, connected in inverse-parallel with it.

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: A modulation method for a pulse width modulator in the inverter section (11) of a frequency converter provided with a voltage intermediate circuit, said frequency converter comprising a single-phase mains bridge (10) to be connected to a single-phase alternating current source (UL, N), a direct-voltage intermediate circuit and a controlled load bridge (11) for feeding a three-phase alternating voltage (UR, US, UT) of varying frequency and amplitude into a load (13), for controlling the semiconductor switches of the inverter section, in which low-capacitance direct-voltage intermediate circuit the waveform of the intermediate-circuit voltage in a normal load situation follows the absolute value of the supply network voltage, and wherein the modulation is implemented using an estimate value of the intermediate-circuit voltage to control the semiconductor switches of the inverter section.

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: A method and a system for protecting the power semiconductor components used in the powerstages of power electronics devices, such as frequency converters, wherein calculation modeling the degree of heating of the semiconductor junction of the power components (V11–V16) is used, wherein the degree of heating of the power components between the measurable outer surface or cooler and the internal semiconductor junction is determined on the basis of the dissipation power and a thermal network model of the component, wherein the temperature of the outer surface of the power component or the temperature of the cooler is measured, wherein the modeled temperature of the semiconductor junction is the sum of the measured temperature of the outer surface or cooler and the calculated degree of heating, and wherein, based on the modeled junction temperature, an alarm is issued or some other protective action is taken.

Abstract: A method and system for the measurement of energy in an alternating-current motor drive containing a frequency converter or an equivalent stepless rotational speed regulator provided with semiconductor switches. In this regulator, the power taken by the motor drive from the mains is determined, and based on the power taken by the motor drive from the mains, the energy taken from the supply mains, especially the accumulated energy consumption after a given instant is determined.

Abstract: A braking chopper for dissipating braking power away from the direct-current rails of an AC drive system, said braking chopper being an inverter unit (INU) physically similar to those also used as motor supply devices, consisting of upper- and lower-branch controllable semiconductor switches (V1–V6), wherein the inverter is connected by its output connectors to the direct-current rails (DC) via a resistor unit, which resistor unit contains two resistors (R1, R2), of which the first is connected to the positive direct-current rail (DC+) and the second to the negative direct-current rail (DC?), wherein both lower-branch and upper-branch semiconductor switches are turned on during braking, and wherein one brake resistor is controlled by the lower-branch switch of only one phase and the second brake resistor by the upper-branch switch of another phase.

Abstract: A method and an apparatus for controlling the mains bridge of a four-quadrant PWM frequency converter provided with a DC intermediate circuit when the power is flowing in the direction towards the supply network, said frequency converter being provided with an AC inductor (9) to be connected to an alternating voltage source (UU, UV, UW), a controlled mains bridge (10), a DC intermediate circuit (14) and a controlled load bridge (11) for feeding a variable-frequency alternating voltage (US, UR, UT) into a load (12), and said mains bridge being provided with controlled semiconductor switches (V1–V6) and shunt diodes (D1–D6), and wherein the mains bridge (10) is mainly controlled in such manner that the controlled semiconductor switch in the upper branch of the phase having the highest supply voltage instantaneous value and the controlled semiconductor switch in the lower branch of the phase having the lowest supply voltage instantaneous value are conducting.

Abstract: A method of arranging frequency converters in a cabinet including placing the frequency converters one above the other in a first section of the cabinet, and passing a cooled medium from a second section to a third section of the cabinet such that the cooled medium flows substantially across parts included in the respective frequency converters. Further, the second and third sections are on adjacent sides of the first section. The method also includes arranging supply voltage and load cabling connected to the frequency converters in at least one of the second or third sections of the cabinet.

Abstract: A method of protecting a frequency converter against overvoltage by controlling an AC motor during braking or during light load and a frequency converter, wherein the frequency converter is a voltage-controlled PWM frequency converter operating in single quadrant (1Q) and comprising at least one uncontrolled rectifier bridge (10) to be connected to a AC supply line (UL1, UL2, UL3), a direct-voltage intermediate circuit and at least one controlled inverter bridge (11) for feeding an AC motor (12) with an alternating voltage (Uu, Uv, Uw) of varying magnitude and frequency, in which method: the angle (??) between the output voltage vector (Us) and current vector (Is), i.e. the power factor, is measured, the angle (??) between the output voltage vector (Us) and current vector (Is), i.e. the power factor, is controlled on the basis of the measurement, and the angle (??) between the output voltage vector (Us) and current vector (Is), i.e.

Abstract: 1.