Ebm-papst St. Georgen Gmbh & Co Kg

Günther Strasser

Frank Jeske

Arnold Kuner

Hans-Dieter Schondelmaier

Hansjörg Berroth

Arno Karwath

Hermann Rappenecker

Alexander Hahn

Frank Heller

Thomas Von Der Heydt

Paul Layes

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

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.

Electronically commutated motor

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.

Method for limiting the current in an electric motor, and a motor for carrying out one such method

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St. Georgen, Germany

Günther Strasser