A method controls the current output of a battery for driving a rail vehicle. A battery actual current I.sub.bat,ist passes via a converter to an asynchronous motor, being a drive for the vehicle. The battery actual current I.sub.bat,ist is set by control circuits as a function of a feedforward control torque M.sub.ff and a specified torque M.sub.tf. The feedforward control torque M.sub.ff is calculated using a transfer function H.sub.sys(z), which maps the torque setpoint value M.sub.soll onto the battery actual current I.sub.bat,ist as follows: I.sub.bat(z) H.sub.sys(z) M.sub.soll(z). Accordingly, a zero-point z=znmp, which lies outside the unit circle, is determined by the transfer function H.sub.sys(z). The feedforward control torque M.sub.ff is calculated as follows: M.sub.ff(z) I.sub.bat,neu(z)/(H.sub.sys(z) z) where: I.sub.bat,neu(z)=I.sub.bat,ideal(z) I.sub.bat,ideal(z=znmp) where: I.sub.bat,neu[n]=I.sub.bat,ideal[n] for all n>0, so that pole point/zero point cancellation is reached by z=znmp at the battery ideal current.

A rotary current machine system and method for controlling an electric rotary current machine, in particular an induction machine, having a rotor, a stator and at least two phase windings is disclosed. At least one electrical signal, in particular a voltage signal, is applied to at least one phase winding, preferably all phase windings, of the rotary current machine, and the current waveform in the at least one phase winding is measured. An intermodulation signal component, induced in the rotary current machine by slotting effects and magnetic saturation effects, which is determined from the current waveform measured in the at least one phase winding, is used for controlling the rotary current machine.

A system and method for dynamically optimizing flux levels in electric motors based on estimated torque. Motor parameters and motor equations are used to estimate operating characteristics and to set current and voltage limits which define an optimal flux operating range for a given speed and torque of the motor. A slope of a linear flux gain is determined within the defined operating range at different speeds of the motor. The determined slopes for the different speeds are saved in a memory element. A control element determines and achieves an optimal flux level for the motor by accessing the table to identify a specific slope which corresponds to an actual speed of the motor, multiplying the slope by the estimated torque and adding an offset value to determine a phase current component value associated with the optimal flux level, and applying the determined phase current component value to the motor.

The invention relates to a method for jointly controlling asynchronous machines (2; 3) of a motor vehicle (1) having a first asynchronous machine (2) and a second asynchronous machine (3) for driving the motor vehicle (1); an inverter (4), which is designed to supply the first asynchronous machine (2) and the second asynchronous machine (3) with a common stator voltage (5) at a common stator frequency (6). The method comprises the steps of determining a specified setpoint drive torque (11) of the motor vehicle (1) for a current driving situation of the motor vehicle (1); sensing a first rotational speed (7a) of the first asynchronous machine (2) and a second rotational speed (7b) of the second asynchronous machine (3); determining a common operating strategy of the first asynchronous machine (2) and of the second asynchronous machine (3) according to the specified setpoint torque (11) while taking into account the sensed rotational speeds (7a; 7b); and controlling the stator voltage (5) and the stator frequency (6) in order to set the drive torques (9a; 9b) of the asynchronous machines (2; 3) according to the operating strategy.

Disclosed are an inverter control device and method. The method according to an embodiment of the present includes estimating a rotation speed of a motor, determining a slip frequency reference using an energy of a direct current terminal capacitor of an inverter, which provides an output voltage to the motor, and a direct current terminal energy reference when a direct current terminal voltage of the inverter is a certain level or less, and providing a frequency reference determined by adding the rotation speed of the motor and the slip frequency reference to the inverter.

The invention relates to a method and system for calibrating a control device, in particular an inverter control device, of an electric motor, comprising operating the electric motor as part of a force flow; performing a force measurement by means of piezo elements which are arranged in the force flow in such a way that the force flow is applied, in particular exclusively, to the piezo elements; and adapting a control characteristic the control device on the basis of at least one force component derived from the force measurement, in particular a change in the at least one force component and/or at least one torque component derived from the force measurement, in particular a change in the torque component.

A device is provided for monitoring the compaction of concrete introduced into a slipform of a slipform paver by means of at least one concrete compacting device that has an asynchronous motor for driving an unbalanced mass which generates vibrations. The monitoring device comprises an apparatus for monitoring the stator current of the asynchronous motor, the apparatus being configured such that a change in the compaction of the concrete is determined based on an analysis of the stator current. The apparatus for monitoring the stator current of the asynchronous motor is preferably configured such that the amplitude spectrum of the stator current is determined in order to analyse the stator current. It is advantageous that the compaction of the concrete is not monitored using sensors which are exposed to harsh ambient conditions during operation of the slipform paver.

According to some embodiments, AC chopping circuit includes a switching circuit, a synchronizing signal generating circuit, a switch driving circuit and an auxiliary power supplying circuit. In some examples, the switching circuit are coupled to an AC power source and a load. In certain examples, the synchronizing signal generating circuit provides a synchronizing signal which is related to a polarity of the AC power source. In some examples, the switching circuit is controlled based at least in part on the synchronizing signal.

The present invention provides a method and system for controlling the temperature of an electric motor by adjusting the electric losses in the motor. In an embodiment, the required load on the motor is determined and a first motor voltage is provided to meet the required load. A predetermined temperature set point for the motor is compared against the temperature of the motor and based on the temperature of the motor and the predetermined temperature set point, a secondary motor voltage is determined. The motor voltage may then be adjusted based on the calculated voltage and the motor load measurement adjusted based on the measured motor speed and actual motor voltage.

This power conversion device comprises: a power converter including a switching element; and a control unit which controls the power converter. The control unit calculates a torque electric current detection value and an excitation electric current detection value from an electric current flowing to an external device, and when an absolute value of the torque electric current detection value is greater than or equal to the excitation electric current detection value, performs control such that the excitation electric current detection value follows the torque electric current detection value.