Abstract: A method for detecting low impedance condition at an output (15) of an electrical converter (10), a control unit (1000), a computer program product, and an electrical converter (10) are presented. The method includes determining (110) a first current value (I1(T1)) of a first current (I1), and a second current value (I1(T2)) of the first current (I1), and determining (120) a first current difference (?I1) between the first (I1(T1)) and the second (I1(T2)) current values, and comparing (130) the first current difference (?I1) to a first current difference threshold (I1_TH), and if the first current difference (?I1) is of predefined magnitude with respect to the first current difference threshold (I1_TH), such as higher, turning off (140) a first voltage (U1) driving the first current (I1), such as by switching off a corresponding switch or switches for applying the first voltage (U1) to the output (15).

Abstract: The invention is directed at an electric power converter, such as an electric motor drive for driving an electric motor. The converter includes a cooling system with a heat sink for dissipating thermal energy generated by the converter and with coolant flow means for cooling the heat sink, first measuring means for measuring the coolant inlet temperature, second measuring means for measuring the heat sink temperature, estimating means for estimating the thermal energy transferred to the heat sink, wherein the converter is provided for estimating the thermal resistance of the heat sink based on the measured temperatures and the estimated thermal energy transferred to the heat sink, for comparing the estimated thermal resistance to reference values and for outputting a signal, if the difference between the estimated thermal resistance and the reference values exceeds a threshold value. The invention is also directed at a method for operating the electric power converter.

Abstract: A controller (203) comprises a processing system (205) for controlling a power electronic converter during a short circuit taking place in a direct voltage side of the power electronic converter. The processing system recognizes a direction of current in a phase (126-128) of an alternating voltage side of the power electronic converter, sets a high-leg controllable switch (108-110) of the phase to a conductive state while keeping a low-leg controllable switch (111-113) of the phase in a non-conductive state when the recognized direction of the current is outwards from the power electronic converter, and otherwise sets the low-leg controllable switch to the conductive state while keeping the high-leg controllable switch in the non-conductive state. Thermal loadings of freewheeling diodes (114-119) of the power electronic converter are reduced since currents needed to burn input fuses (122) of the power electronic converter are shared between the controllable switches and the freewheeling diodes.

Abstract: A method for detecting low impedance condition at an output (15) of an electrical converter (10), a control unit (1000), a computer program product, and an electrical converter (10) are presented. The method includes determining (110) a first current value (I1(T1)) of a first current (I1), and a second current value (I1(T2)) of the first current (I1), and determining (120) a first current difference (?I1) between the first (I1(T1)) and the second (I1(T2)) current values, and comparing (130) the first current difference (?I1) to a first current difference threshold (I1_TH), and if the first current difference (?I1) is of predefined magnitude with respect to the first current difference threshold (I1_TH), such as higher, turning off (140) a first voltage (U1) driving the first current (I1), such as by switching off a corresponding switch or switches for applying the first voltage (U1) to the output (15).

Abstract: A controller (203) comprises a processing system (205) for controlling a power electronic converter during a short circuit taking place in a direct voltage side of the power electronic converter. The processing system recognizes a direction of current in a phase (126-128) of an alternating voltage side of the power electronic converter, sets a high-leg controllable switch (108-110) of the phase to a conductive state while keeping a low-leg controllable switch (111-113) of the phase in a non-conductive state when the recognized direction of the current is outwards from the power electronic converter, and otherwise sets the low-leg controllable switch to the conductive state while keeping the high-leg controllable switch in the non-conductive state. Thermal loadings of freewheeling diodes (114-119) of the power electronic converter are reduced since currents needed to burn input fuses (122) of the power electronic converter are shared between the controllable switches and the freewheeling diodes.

Abstract: Liquid-cooled power unit of a power electronics device, which power unit includes at least two power modules, the cooling surface of which power modules is provided with pin-type protrusions and which power modules are fixed to the frame part of the power unit. A liquid duct is arranged inside the frame part of the power unit, and the power modules are fixed to the points of the apertures situated in the frame part on both sides of the liquid duct in such a way that the pin-type protrusions of the power modules are situated in the liquid duct. A wedge-shaped part is disposed in the liquid duct, which wedge-shaped part includes a wedge-shaped front part for spreading the liquid flow into two essentially equal flows at the point of the power modules.

Abstract: Liquid-cooled power unit of a power electronics device, which power unit includes at least two power modules, the cooling surface of which power modules is provided with pin-type protrusions and which power modules are fixed to the frame part of the power unit. A liquid duct is arranged inside the frame part of the power unit, and the power modules are fixed to the points of the apertures situated in the frame part on both sides of the liquid duct in such a way that the pin-type protrusions of the power modules are situated in the liquid duct. A wedge-shaped part is disposed in the liquid duct, which wedge-shaped part includes a wedge-shaped front part for spreading the liquid flow into two essentially equal flows at the point of the power modules.

Abstract: Cooling arrangement for the power components (10) of a power transformer, in which is a cooler (12), which has a metal frame, to which the power components can be fitted, and cooling piping fitted inside the frame for removing thermal power from the power components by means of a flowing cooling medium, and a condenser (13) connected to the cooling piping, with which thermal power can be transferred out of the cooling piping. The cooler and the condenser have a shared metal frame (11), in which one part functions as the cooler part and the other part as the condenser part, and inside which is fitted the shared cooling piping of the cooler and the condenser for the flowing cooling medium.

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 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: 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 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: 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.