Control device and control method for an electric drive system, and electric drive system
The invention relates to controlling an electric drive system, a control range for the switching frequency of a power converter in such a drive system being adaptable when the rotational frequency curve or the torque curve of the electrical machine is taken into account. In this way, psycho-acoustic irritations can be avoided.
1. A control device ( 1 ) for an electric drive system comprising a power converter ( 2 ) and an electrical machine ( 3 ), the control device ( 1 ) comprising:
a monitoring unit ( 11 ) designed to determine a rotational frequency and/or a torque of the electrical machine ( 3 ), and to determine a variation of the determined rotational frequency and/or of the determined torque; and
a control unit ( 12 ) configured to define a control range for a switching frequency of the power converter ( 2 ) using the variation of the rotational frequency and/or the variation of the torque, and to control the power converter ( 2 ) with a switching frequency in the defined control range.
2. The control device ( 1 ) according to claim 1 , wherein the monitoring unit ( 11 ) is configured to calculate the variation of the rotational frequency and/or of the torque using a gradient of the rotational frequency and/or of the torque.
3. The control device ( 1 ) according to claim 1 , wherein the monitoring unit ( 11 ) is configured to detect a current actual rotational frequency and/or a current actual torque, and/or to receive a desired rotational frequency and/or a desired torque.
4. Control The control device ( 1 ) according to claim 1 , wherein the control unit ( 12 ) is configured to define a current switching frequency as the lower limit frequency of the control range for the switching frequency if the rotational frequency and/or the torque increases, and/or to define the current switching frequency as the upper limit frequency of the control range for the switching frequency if the rotational frequency and/or the torque decreases.
5. The control device ( 1 ) according to claim 1 , wherein the control unit ( 12 ) is configured to define a predetermined maximum switching frequency as the upper limit frequency of the control range for the switching frequency if the rotational frequency and/or the torque increases, and/or to define a predetermined minimum switching frequency as the lower limit frequency of the control range for the switching frequency if the rotational frequency and/or the torque decreases.
6. The control device ( 1 ) according to claim 1 , wherein the control unit ( 12 ) is configured to adapt a modulation method for controlling the power converter ( 2 ) using the determined rotational frequency and/or the determined torque.
7. The control device ( 1 ) according to claim 1 , further comprising a characteristic curve memory ( 13 ) which is configured to store and provide at least one characteristic curve for controlling the power converter ( 2 ),
wherein the control unit ( 12 ) is designed to control the power converter ( 2 ) using the characteristic curve stored in the characteristic curve memory.
8. The control device ( 1 ) according to claim 1 , wherein the control unit ( 12 ) is configured to adapt the control of the power converter ( 2 ) using at least one further operating parameter.
9. An electric drive system comprising:
an electrical machine ( 3 );
a power converter ( 2 ) designed to control the electrical machine ( 3 ); and
a control unit ( 1 ) configured
determine a current rotational frequency and/or a current torque of the electrical machine ( 3 );
determine a variation of the determined rotational frequency and/or of the determined torque;
define a control range for a switching frequency of the power converter ( 2 ) using the variation of the rotational frequency and/or the variation of the torque; and
control the power converter ( 2 ) with a switching frequency in the defined control range.
10. A method for controlling an electric drive system comprising a power converter ( 2 ) and an electrical machine ( 3 ), comprising the steps of:
determining (S 1 ) a current rotational frequency and/or a current torque of the electrical machine ( 3 );
determining (S 2 ) a variation of the determined rotational frequency and/or of the determined torque;
defining (S 3 ) a control range for a switching frequency of the power converter ( 2 ) using the variation of the rotational frequency and/or the variation of the torque; and
controlling (S 4 ) the power converter ( 2 ) with a switching frequency in the defined control range.