Control method for braking an electric motor, control method for controlling an electric drive unit and computer program product

A control method for controlling an electric drive unit for an electric handheld power tool, the electric drive unit having an electric motor having a stator winding and a rotor winding, an actuating circuit for actuating the electric motor and a connection unit for coupling an energy source for driving the electric motor, the stator winding being connected via a first node to a stator-side first half-bridge including a first semiconductor component and a second semiconductor component and is connected via a second node to the rotor winding, wherein the rotor winding is connected to a third node connected via a conductive component to the connection unit, and wherein the actuating circuit includes a third semiconductor component connected via the second node to the rotor winding and the stator winding and is connected via a fourth node directly to the connection unit, wherein the control method comprises:

• a) moving the first semiconductor component to a non-conductive state in order to switch the electric motor from motor operation to braking operation,
• b) moving the first semiconductor component and the third semiconductor component to a conductive state in order to reverse the polarity of an input voltage applied to the rotor winding compared to motor operation,
• c) moving the first semiconductor component to a non-conductive state as a function of a predetermined threshold value for a rotor current through the rotor winding in order to limit the rotor current, and
• d) moving the first semiconductor component alternately to a conductive state and to a non-conductive state in order to regulate a stator current through the stator winding as a function of a current rotation speed of the electric motor.

A control method for controlling an electric drive unit for an electric handheld power tool, wherein the electric drive unit has an electric motor having a stator winding and a rotor winding, an actuating circuit for actuating the electric motor and a connection unit for coupling an energy source for driving the electric motor, wherein the stator winding is connected via a first node to a stator-side first half-bridge comprising a first semiconductor component and a second semiconductor component and is connected via a second node to the rotor winding, wherein the actuating circuit includes a third semiconductor component connected via the second node to the rotor winding and the stator winding and is connected via a fourth node directly to the connection unit, wherein the rotor winding is connected to a third node connected via a fourth semiconductor component to the connection unit, and wherein the actuating circuit includes a fifth semiconductor component connected via the third node to the rotor winding and via a fifth node directly to the connection unit, wherein the control method comprises:

• a) moving the first semiconductor component or the fourth semiconductor component to a non-conductive state in order to switch the electric motor from motor operation to braking operation,
• b) moving the third semiconductor component and the fifth semiconductor component to a conductive state in order to reverse the polarity of an input voltage applied to the rotor winding compared to motor operation,
• c) moving the fourth semiconductor component and the fifth semiconductor component to a non-conductive state as a function of a predetermined threshold value for a rotor current through the rotor winding alternately in synchronism with opposite senses to a conductive state and to a non-conductive state in order to limit the rotor current, and
• d) moving the first semiconductor component alternately to a conductive state and to a non-conductive state in order to regulate a stator current through the stator winding as a function of a current rotation speed of the electric motor.