Method for monitoring a coil temperature
AssigneeSiemens Aktiengesellschaft
InventorsZeljko Jajtic, Peter Sachsenhauser, Jürgen Böhling, Tobias Taubald, Christian Volmert
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Abstract
In a method for monitoring a winding temperature of a winding of an electric machine powered by a converter, a heating power applied to the winding of the electric machine is determined and evaluated using a thermal model. A relative increase in a resistance of the winding, when the winding heats up, is determined from the heating power in comparison with a standard reference value for 20° C. winding temperature. The winding temperature is calculated from the relative increase in the resistance, and a warning signal and/or a switch-off signal is generated when a critical winding temperature value is exceeded.
Claims12
A method for monitoring a winding temperature of a multiphase winding of an electric machine powered by a multiphase AC/AC converter, said method comprising:
- determining electrical power applied from an output of the multiphase AC/AC converter to the multiphase winding of the electric machine;
- determining a heating power dissipated by the multiphase winding from a product of output voltages and output currents measured for each phase at the multiphase AC/AC converter after subtracting from the electrical power a mechanical power generated by the electric machine;
- determining a relative increase in a resistance of the multiphase winding caused by the dissipated heating power, when the winding heats up, in comparison with a reference resistance value at a reference winding temperature;
- calculating the winding temperature from the relative increase in the resistance of the multiphase winding, using a known temperature dependence of the resistance of the multi hale winding;
- and
- generating a warning signal and/or a switch-off signal when a critical winding temperature value is exceeded.
Apparatus for monitoring a winding temperature of a multiphase winding of an electric machine powered by a multi phase AC/AC converter, said apparatus configured to:
- determine electrical power applied from an output of the multiphase AC/AC converter to the multiphase winding of the electric machine,
- determine a heating power dissipated by the multiphase winding from a product of output voltages and output currents measured for each phase the multiphase AC/AC converter after subtracting from the electrical power a mechanical power generated by the electric machine;
- determine a relative increase in a resistance of the multiphase winding caused by the dissipated heating power, when the winding heats up, in comparison with a reference resistance value at a reference winding temperature;
- calculate the winding temperature from the relative increase in the resistance of the multiphase winding, using a known temperature dependence of the resistance of the multiphase winding;
- and
- generate a warning signal and/or a switch-off signal when a critical winding temperature value is exceeded.
A drive, comprising:
- a dynamoelectric machine including a multiphase winding;
- a multiphase AC/AC converter powering the dynamoelectric machine;
- and
- an apparatus for monitoring a winding temperature of the multiphase winding of the dynamoelectric machine, said apparatus configured to:
- determine electrical power applied from an output of the multiphase AC/AC converter to the multiphase winding of the electric machine,
- determine a heating power dissipated by the multiphase winding from a product of output voltages and output currents measured for each phase at the multiphase AC/AC converter after subtracting from the electrical power a mechanical power generated by the electric machine;
- determine a relative increase in a resistance of the multiphase winding caused by the dissipated heating power, when the winding heats up, in comparison with a reference resistance value at a reference winding temperature;
- calculate the winding temperature from the relative increase in the resistance of the multiphase winding, using a known temperature dependence of the resistance of the multiphase winding;
- and
- generate a warning signal and/or a switch-off signal when a critical winding temperature value is exceeded.
Dependencies are inferred from the claim text.