Robert Boschgmbh

Claude Berling

Wolfgang Schwenk

Joerg Sutter

Wolfgang Krauth

Volker Lurk

Electronically commutable motor whose output stages are controllable by an electronic control unit, using PWM control signals, and are feedable from a supply voltage source. A limitation to a maximum load with overload protection is achieved, at least upon exceeding the nominal voltage of the motor, by reducing the pulse width of the PWM control signals for the output stages to a width that prevents overloading of the motor and electronic components by limiting the motor output, as a function of the magnitude of the supply voltage and the specified setpoint for the PWM control signals.

Electronically switchable motor with overload protection

An electronically commutatable motor having field windings activatable in sequence with a commutation frequency via semiconductor output stages using control signals connectable and disconnectable from a direct voltage supply, the control signals being clocked using pulse width modulation. Noise generation from connection and disconnection of the current applied to field windings is minimized by flattening of the rising and/or falling edges of the current in the field windings. The pulse width ratio increases in the rising edges of the control signals from a low initial value to an operating value assigned to the setpoint as a function of a selected setpoint for the motor speed or output, and, in the falling edges of the control signals, the pulse width ratio starts from the existing operating value and is reduced to a lower final turn-off value as a function of the existing actual value of the speed or the output of the motor.

Method of controlling an electronically commutatable motor

An electronically commutatable motor, whose excitation windings are controllable via semiconductor output stages by an electronic control unit with the aid of PWM control signals, a setpoint value being specifiable to the control unit, and the control unit emitting corresponding PWM control signals to the semiconductor output stages; a motor characteristic curve, from which an assigned nominal operating speed is derivable for the setpoint value being stored in the control unit, and the derived nominal operating speed being able to be compared to the actual speed of the motor. It a predefinable or predefined speed difference between the nominal operating speed and the actual speed is exceeded, the control unit and/or the semiconductor output stages can be switched off. The derivation of the nominal operating speed for the predefined setpoint value is facilitated by a three-dimensional characteristics field determined by four coordinate points.

Electronically commutated motor

An electronically commutatable motor is disclosed, whose field windings are controllable via electronic control unit using PWM control signals via semiconductor output stages, a setpoint being selectable for the control unit and the control unit outputting corresponding PWM control signals to the semiconductor output stages. In order to recognize malfunctions which could result in overload of the motor and the electronic components thereof even in the acceleration phase and to be capable of using this to protect against overload, after selection of the setpoint and/or switching on of the control unit and/or the semiconductor output stages, the control unit outputs ramp-type speed-increasing PWM control signals to the semiconductor output stages during a selected or selectable acceleration time until the final control of the semiconductor output stages corresponding to the setpoint is reached, during the acceleration time a setpoint speed corresponding to the PWM control signals may be compared with the detected actual speed of the motor, and, in the event of deviations of the actual speed from the setpoint speed by a selected or selectable speed deviation, the control unit and/or the semiconductor output stages may be switched off.

Electronically commutatable motor comprising an electronic control unit

An electronically commutatable motor, whose excitation windings are controllable via semiconductor output stages by an electronic control unit with the aid of PWM control signals, a setpoint value being specifiable to the control unit, and the control unit emitting corresponding PWM control signals to the semiconductor output stages. The start-up of the motor is monitored in a simple manner and an overloading is prevented in that, with the input of the setpoint value and/or the switching on of the control unit and/or the semiconductor output stages, after a predefined or predefinable starting time has expired, a monitoring device monitors the speed of the motor to check whether a minimum speed has been reached, and if the minimum speed is not reached, the control unit and/or the semiconductor output stages is/are disconnectible.

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Drusenheim, France

Claude Berling