Ebm-papst St. Georgen Gmbh & Co Kg

Hansjörg Berroth

Frank Jeske

Arnold Kuner

Hans-Dieter Schondelmaier

Günther Strasser

Arno Karwath

Hermann Rappenecker

Alexander Hahn

Frank Heller

Nils Rapp

Thomas Von Der Heydt

Paul Layes

Volker Mauch

For many applications, it is desirable to use fans which weigh less than 30 grams and are driven by electric motors not more than a few centimeters in size. Mass-producing products this small, which nevertheless must be extremely reliable, poses unique manufacturing challenges, which are best overcome by an improved structure which is susceptible to automation. Preferably, the fan motor is electronically commutated and has an internal stator () and an external rotor () supported on a central rotor shaft (). The shaft is journaled within a bearing tube () supporting first and second rotor bearings (). By injection-molding the bearing tube () with first and second axial extensions (), the extensions can hold the bearings in place and insure uniform manufacturing quality and a desirably long service life. One of the extensions can also be shaped to abut against a circuit board () which supports components which control commutation.

Electronically commutated motor

An arrangement for pumping fluids has an electronically commutated external-rotor motor. The latter has a stator arranged on a stator carrier and a rotor joined to a first permanent magnet, which rotor is rotatably journaled, in a bearing tube, with respect to the stator. This bearing tube is arranged, at least partly, radially inside the stator carrier. The first permanent magnet is arranged in an annular interstice between the stator carrier and the bearing tube. A fluid pump has a pump wheel arranged rotatably inside a pump housing, which wheel is joined to a second permanent magnet, a liquid-tight but magnetically transparent partition being provided between the first permanent magnet and the second permanent magnet. This keeps fluid away from the motor wiring. The first permanent magnet forms, by coaction with the second permanent magnet, a magnetic coupling to the fluid pump, which magnetic coupling automatically produces a rotation of the pump wheel as a result of rotation of the motor rotor.

Assembly for transporting fluids

A control circuit for an electronically commutated motor (), having a power stage () that comprises at least two semiconductor switches () to influence the motor current. The semiconductor switches are controllable by way of commutation signals. The control circuit comprises a current measuring element () to make available a motor current control variable (I) dependent on the motor current, a base diode () that is arranged in series with the current measuring element and between the current measuring element and the at least two semiconductor switches, and a motor current setting element () with which the commutation signals can be influenced as a function of the motor current control variable.

Control circuit for an electronically commutated motor

An improved method of commutating an electronically commutated motor () is disclosed. The motor has a positive () and a negative connecting lead (), a stator having at least one winding phase (), a permanent-magnet rotor (), a rotor-position sensor () for producing a rotor position signal (u, u), and a full bridge circuit (), comprising a pair of Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) coupled to each end of each winding phase (). In order to prevent current shoot-through and prolong the service life of the MOSFETs, without employing a microprocessor, a respective-comparator (') is coupled to the gate of each MOSFET, in order to assure that the MOSFET is switched ON and OFF at an optimum time.

Method for commutating an electronically commutated motor and motor for carrying out said method

A method is disclosed for controlling the commutation in an electronically commutated motor () which comprises a stator having at least one phase (), and a permanent-magnet rotor (), and with which a current limiter () and a controller () for regulating a motor variable are associated. The current limiter () serves to limit the current (I) in the at least one phase () to a setpoint value. The regulation by means of the controller () is accomplished by modifying the distance in time (W) between switching on (t) and switching off (t) of the current (i, i) in the at least one phase. In this method, the setpoint value to which the current limiter limits the current (i, i) in the relevant phase is modifiable. It is modified substantially as a function of a ratio of two times (W/T), namely as a function of the ratio of the distance in time (W) between switching on (t) and switching off (t) of the current (i, i) in the relevant phase () to the time period (T) required by the rotor, at the instantaneous rotation speed, to rotate through a specified rotation angle. A decrease in noise at low rotation speeds is thereby made possible.

Method of controlling the commutation in an electronically commutated motor, and an electronically commutated motor for carrying out said method

In a method for controlling a physical variable in an electronically commutated motor, current is supplied to the stator winding arrangement () of the motor in the form of current blocks. The interval (BW) between the switch-on command and switch-off command for controlling those current blocks, i.e. the length (BW) of the control signals, is influenced by a control apparatus, and the effective current value of those current blocks is influenced by setting a pulse duty factor (pwm). The length of the control signals is limited in both directions. If a control signal becomes shorter than a specified lower limit, the pulse duty factor (pwm) is decreased, so that the effective value of the current falls and the length (BW) of the current blocks is increased by the control system. If a control signal becomes longer than a specified upper limit, the pulse duty factor is increased, so that the effective value of the current rises and the length of the current blocks decreases in compensatory fashion.

Method of controlling a physical variable in an electronically commutated motor, and motor for carrying out said method

An improved method of commutating an electronically commutated DC motor shuts off application of power between the end of one current pulse and the beginning of the subsequent current pulse. Based upon the instantaneous rotation speed, one calculates at what instant to shut off the power. During the power interruption, the disconnected winding is operated in short-circuit mode using two MOSFET transistors, and the decay of the current is monitored. When the current reaches a predetermined reduced value, the terminals of the winding are switched to a high-resistance state, until the subsequent current pulse is started. This has the advantage that less reactive power occurs during operation, and one need not install as bulky a storage capacitor as the capacitors used heretofore.

Method for commutating an electronically commutated DC motor, and motor for carrying out said method

An electronically commutated motor has a rotor (), a stator having a stator winding arrangement (), and a full bridge circuit () for controlling the current (i, i) in the stator winding arrangement (); in the full bridge circuit (), first semiconductor switches () are connected to a first DC supply lead () and second semiconductor switches () to the other DC supply lead (), said second switches being bidirectionally conductive of current in the switched-on state. The motor has an arrangement () for opening the first semiconductor switches () and for closing the second semiconductor switches () during a predetermined operating state. An arrangement () is provided for monitoring the direction of the current (i, i) which flows in the second semiconductor switches () when the latter are conductive during the predetermined operating state.

A method of limiting current in a DC motor acts on a full bridge circuit () through which the stator winding arrangement () of that motor is supplied with current. Upon response of the current limiter, energy supply to the stator winding arrangement () from the DC power network is interrupted. The stator winding arrangement is then operated substantially in short circuit via semiconductor switches of the full bridge circuit, and the decaying current flowing in that context serves substantially to continue driving the motor. When that current has reached a lower value, energy supply from the DC power network to the motor is once again activated. The effective value of the current flowing to the motor is preferably reduced when the current limiter responds. The time period during which that current flows, in the form of current blocks, is then increased in compensatory fashion.

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VS-Obereschach, Germany

Hansjörg Berroth