Robert Boschgmbh

Wolfgang Schwenk

Joerg Sutter

Claude Berling

Wolfgang Krauth

Robert Kern

Karl-Heinrich Preis

Thomas Mohr

Martin Heyder

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

A method is for starting a sensorless and brushless direct current motor, the stator windings of which are supplied with power from a multiphase converter circuit. For starting the motor, it is first rotated into a defined starting position in an alignment operation through simultaneous energization of at least two phases. Then in a second phase, an energization state of the stator windings which is in the desired direction of rotation and provides sufficient torque is initiated, whereupon then the additional energization states of the corresponding phases follow cyclically, and the rotor is rotated in synchronization with the applied stator rotational field. The motor may be used in a motor vehicle and supplied with the battery voltage at the input terminals. In an example embodiment, the current supplied in the alignment is adjusted according to the battery voltage, and in addition, it is increased according to a specified waveform. This ensures reliable and rapid rotation without overshooting into the starting position.

Method for starting a sensor- and brushless d.c. motor

The present invention provides a method for shifting the instant of commutation for a sensorless and brushless direct-current motor ( ), whose stator windings are fed by a multi-phase converter connection. The converter connection includes an output stage control ( ), a commutation logic ( ), a phase selector ( ), and phase discriminator ( ). A commutation detection ( ) is supplied at one input ( ) with the instantaneous value of the voltage induced in a phase, the instantaneous value being determined by the phase selector, and at a second input ( ), with a reference voltage (U ) for comparison. The reference voltage (U ) can be changed by a commutation shift ( ) in correspondence with a specific characteristic curve ( ). A manipulated variable (U ) is supplied by a manipulated-variable calculation ( ) to the commutation shift ( ) as a function of the setpoint speed (N ) of the motor. The commutation shift takes place in an advantageous manner in a parabola shape. As a result of the setpoint value-dependent commutation shift, a high torque is provided also in the case of high rotational speeds and a heavy load, and the torque ripple is kept to a minimum.

Method for shifting the instant of commutation for a sensorless and brushless direct-current motor as well as a system for implementing the method

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.

Electronically commutable motor

A device and method for driving a polyphase DC motor, in which a phase selector circuit, in each case, selects only one phase, which is fed to a commutation detection circuit. After each commutation detected by a commutation detection circuit, as a result of a pulse of constant duration generated by a monoflop, the phase discriminator circuit and, as a consequence, the commutation logic are advanced in a fixed and preestablished sequence. This occurs irrespective of the rotation direction of the motor using the sequential logic device embodied by the commutation logic. When the motor rotates in the preferred direction, constant current-flow angles of 120&deg; are achieved for each phase. When the motor rotates in the reverse direction, markedly varying current-flow angles of the individual phases are generated, and these varying current-flow angles, as a function of the course of the specifically corresponding voltages induced in the individual phases, result in a counter-torque. This counter-torque causes a braking of the motor to a standstill and a reliable startup in the preferred direction. The exemplary electronics, in this context, do not distinguish between the two rotation directions so that no additional electronics expense is required to reliably startup from a reverse rotation condition.

Method and device for controlling an electronically commutated polyphase D.C. motor

A control circuit for a direct-current motor driven in a clocked manner, includes an electrolytic capacitor connected in parallel and free-wheeling diode. Spurious radiation is reduced, in that a choke is connected between the positive motor supply voltage and the plus terminal of the electrolytic capacitor, and that the free-wheeling diode is disposed with its cathode between the choke and the electrolytic capacitor, and with its anode on the negative side of the d.c. motor.

Control circuit for a dc motor

A motor with a fan wheel for forming an axial or radial fan, having a drive unit and a control unit that has a control housing. The drive unit has a stator, a rotor, and at least one electric coil, and the control unit has an electronic circuit for open- or closed-loop control of the supply of current to the coil. The drive unit and the control unit are formed by modules, and contact elements associated with one another are provided for mutual electrical connection.

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Oberkirch-Tiergarten, Germany

Wolfgang Schwenk