Patents by Inventor Ari Ristimäki
Ari Ristimäki has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20230156981Abstract: 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.Type: ApplicationFiled: November 14, 2022Publication date: May 18, 2023Inventors: Ari Ristimäki, Juha Norrena, Tuomas Yli-Rahnasto, Pekka Hemminki, Jani Matti Perkiö
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Patent number: 11183836Abstract: An electronic circuit includes: a first series-connection of DC link capacitors (CA1, . . . , CAm) and a second series-connection of DC link capacitors (CB1, . . . , CBn) connected in parallel between DC bus bars (DC+, DC?), wherein the first series has a first node (A) between the DC link capacitors thereof and the second series has a second node (B) between the DC link capacitors thereof; and a short-circuit module (301; 401, 407) configured to receive a voltage difference (UM) between the first node and the second node and to cause the DC bus bars short circuited in response to the received voltage difference being greater than a predetermined threshold.Type: GrantFiled: May 29, 2019Date of Patent: November 23, 2021Assignee: Vacon OyInventors: Tommi Keski-Kujala, Ari Ristimäki, Pekka Hemminki, Jani Matti Perkiö
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Publication number: 20210285053Abstract: The present invention relates to biomarkers, such as L1NE-1 type transposase domain containing 1 (L1TD1) as predictive prognostic markers of colon cancer. The invention also relates to a method of prognosing colon cancer, and to a kit for use in said method.Type: ApplicationFiled: May 29, 2019Publication date: September 16, 2021Applicant: Turun yliopistoInventors: Deepankar CHAKROBORTY, Emani Maheswara REDDY, Laura ELO, Riitta LAHESMAA, Ari RISTIMÄKI, Caj HAGLUND
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Patent number: 10707777Abstract: A method and arrangement for controlling semiconductor power switches, e.g. IGBTs, in parallel connected power devices, e.g. in frequency converters, wherein the semiconductor power switches connect either the positive or the negative pole of the intermediate DC-voltage of the power device to an output phase of the power device. In the method the voltages of those output phases which are connected in parallel are measured, the timing differences of the output voltage state changes are calculated on the basis of the output voltage measurement results, and the control signals of the semiconductor power switches are advanced or delayed such that the output voltage state changes in the phases which are connected together via output impedances occur at desired time instants.Type: GrantFiled: September 27, 2016Date of Patent: July 7, 2020Assignee: Vacon OyInventors: Jussi Pouttu, Ari Ristimäki, Toni Itkonen
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Publication number: 20190386576Abstract: An electronic circuit includes: a first series-connection of DC link capacitors (CA1, . . . , CAm) and a second series-connection of DC link capacitors (CB1, . . . , CBn) connected in parallel between DC bus bars (DC+, DC?), wherein the first series has a first node (A) between the DC link capacitors thereof and the second series has a second node (B) between the DC link capacitors thereof; and a short-circuit module (301; 401, 407) configured to receive a voltage difference (UM) between the first node and the second node and to cause the DC bus bars short circuited in response to the received voltage difference being greater than a predetermined threshold.Type: ApplicationFiled: May 29, 2019Publication date: December 19, 2019Inventors: Tommi Keski-Kujala, Ari Ristimäki, Pekka Hemminki, Jani Matti Perkiö
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Publication number: 20180269805Abstract: A method and arrangement for controlling semiconductor power switches, e.g. IGBTs, in parallel connected power devices, e.g. in frequency converters, wherein the semiconductor power switches connect either the positive or the negative pole of the intermediate DC-voltage of the power device to an output phase of the power device. In the method the voltages of those output phases which are connected in parallel are measured, the timing differences of the output voltage state changes are calculated on the basis of the output voltage measurement results, and the control signals of the semiconductor power switches are advanced or delayed such that the output voltage state changes in the phases which are connected together via output impedances occur at desired time instants.Type: ApplicationFiled: September 27, 2016Publication date: September 20, 2018Inventors: Jussi Pouttu, Ari Ristimäki, Toni Itkonen
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Patent number: 8670253Abstract: A converter includes a converter bridge (101) adapted to transfer electrical energy between the AC terminal (102) and the DC terminal (103) of the converter. The converter also includes electrical paths bypassing the converter bridge for conducting overvoltage transients occurring in the AC terminal around the converter bridge to the DC terminal. Each electrical path includes a unidirectionally conductive semiconductor component (104a, 104b, 104c), such as a diode, and a voltage-limiting component (105) for which the ratio of voltage change to current change is small when the voltage of the voltage-limiting component is greater than a predetermined threshold voltage. Because of the overvoltage protection thus achieved, AC chokes can be omitted from the AC terminal or at least they can be designed smaller, reducing the load-dependent voltage drop of the DC terminal.Type: GrantFiled: July 16, 2010Date of Patent: March 11, 2014Assignee: Vacon OyjInventors: Ari Ristimäki, Nicklas Södö, Matti Takala, Mika Levonen
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Publication number: 20110044080Abstract: A converter includes a converter bridge (101) adapted to transfer electrical energy between the AC terminal (102) and the DC terminal (103) of the converter. The converter also includes electrical paths bypassing the converter bridge for conducting overvoltage transients occurring in the AC terminal around the converter bridge to the DC terminal. Each electrical path includes a unidirectionally conductive semiconductor component (104a, 104b, 104c), such as a diode, and a voltage-limiting component (105) for which the ratio of voltage change to current change is small when the voltage of the voltage-limiting component is greater than a predetermined threshold voltage. Because of the overvoltage protection thus achieved, AC chokes can be omitted from the AC terminal or at least they can be designed smaller, reducing the load-dependent voltage drop of the DC terminal.Type: ApplicationFiled: July 16, 2010Publication date: February 24, 2011Applicant: VACON OYJInventors: Ari Ristimäki, Nicklas Södö, Matti Takala, Mika Levonen
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Patent number: 6416961Abstract: The present invention pertains to a method for determination of the significance of a histologically detected premalignant lesion as a risk for intestinal type gastric cancer or carcinoma in situ, comprising detecting from a patient sample comprising gastric mucosa cells a) cyclooxygenase-2 Cox-2) mRNA expression, or b) Cox-2 protein; wherein overexpression of Cox-2 is indicative of an increased risk for intestinal type gastric cancer.Type: GrantFiled: September 14, 1999Date of Patent: July 9, 2002Assignee: Biohit OyjInventors: Ari Ristimäki, Matti Härkönen, Pentti Sipponen