Robert Boschgmbh

Christian Djonga

Michele Hirsch

Torsten Heidrich

Markus Kretschmer

Tobias Werner

Michael Heeb

Daniel Zimmermann

Stefan Gaab

The invention provides a method and an apparatus for estimating an RMS current (I) of an intermediate circuit capacitor (C) for a complete system of a battery (), an inverter () and an N-phase electrical machine (), wherein, in the complete system, the inverter () converts a DC power received from the battery () for the purpose of energizing the electrical machine with N phase currents, and wherein the RMS current (I) of the intermediate circuit capacitor to be estimated is calculated according to a calculation rule which is supplied with predefined switching times (t, t) of the N phases of the electrical machine, measured phase currents (IS, IS, IS) of N-1 phases or N phases of the electrical machine and a predefined battery direct current (I) as input variables. This makes it possible to exactly estimate the RMS current (I) of an intermediate circuit capacitor for any desired pulse patterns for controlling the inverter.

Method and apparatus for estimating an RMS current of an intermediate circuit capacitor for an inverter

The invention relates to a method for estimating a temperature contribution of an inverter used to energize an electrical machine, in particular a synchronous machine. The method comprises the steps for calculating oscillating temperature swings of components of the inverter; and determining, as the estimated temperature contribution (&#x394;T(&#x3c9;), &#x394;Ti(&#x3c9;), (&#x394;Td(&#x3c9;)) of the inverter, an upper envelope of an amplitude of a sum of the calculated oscillating temperature swings. The method according to the invention or an apparatus designed to carry out the method can be expanded for the purpose of estimating a temperature or a complete temperature contribution of the inverter and is provided, in particular, for use in an electric vehicle or a hybrid vehicle having an electrical drive without a variable speed gear in order to estimate the operating temperature of vehicle drive power electronics accommodated therein.

Method and apparatus for estimating a temperature contribution of an inverter for an electrical machine

The invention relates to a method for operating an electrical machine () controlled by an inverter (), wherein the inverter () comprises half-bridge branches (-U,-V,-W) having power components in the form of controllable power switching elements () and power diodes () respectively connected in parallel therewith, wherein each of the half-bridge branches (-U;-V;-W) is arranged on a separate semiconductor module (-U;-V;-W), which are arranged jointly on a baseplate (), wherein the phase currents (1_U, 1_V, 1_W) flowing through the half-bridge branches (-U,-V,-W), the voltages present at the power components and temperatures (t_Sens_U, t_Sens_V, t_Sens_W) on the semiconductor modules (-U,-V,-W) are determined, from the current (1_U; 1_V; 1_W) respectively flowing at a power component and from the voltage respectively present a power loss (P) is calculated for each of the power components, from the power losses (P) a relevant temperature swing (&#x394;t; &#x394;t_Sens) is determined for each of the power components and for temperature sensors (-U,-V,-W) serving to determine the temperatures on the semiconductor modules, a temperature (TempCooler) of the baseplate () is determined from the determined temperatures (t_Sens_U, t_Sens_V, t_Sens_W) on the semiconductor modules (--V,-W) and the determined temperature swings (&#x394;t_Sens) at the temperature sensors (-U,-V,-W), and a torque or a power of the electrical machine () is determined in a manner dependent on the determined temperature swings (&#x394;t) and the determined temperature (TempCooler) of the baseplate ().

Control device and method for operating an electrical machine driven by an inverter

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Heilbronn, Germany

Christian Djonga