Ebm-papst St. Georgen Gmbh & Co Kg

Hans-Dieter Schondelmaier

Arnold Kuner

Frank Jeske

Hansjörg Berroth

Günther Strasser

Arno Karwath

Hermann Rappenecker

Alexander Hahn

Frank Heller

Thomas Von Der Heydt

Paul Layes

Hansjorg Berroth

Hansj&ouml;rg Berroth

The invention concerns a method for generating an alarm signal in a motor which comprises a rotor () whose actual rotation speed during operation lies in a normal zone (nSoll, TSoll), can deviate from that normal zone in the event of a fault, and is to be monitored against a malfunction or fault state, comprising the following steps: At least one alarm switch-on rotation speed (nAOn, TAOn) and at least one alarm switch-off rotation speed (nAOff, TAOff) are defined, of which the latter is located closer to the normal zone than the former, an associated pair of alarm switch-on rotation speed and alarm switch-off rotation speed defining between them a hysteresis zone. When the rotation speed to be monitored arrives, coming from the hysteresis zone, at the alarm switch-on rotation speed, an alarm switch-on criterion (Flag DIR=0) is generated. The duration of this alarm switch-on criterion is monitored. When this duration reaches a predetermined value (tdOn), an alarm signal (ALARM) is activated (FIG.: S, S). A corresponding microprocessor-controlled motor can be used to implement the method.

Method and apparatus for monitoring motor rotation speed

The invention concerns a method for determining a numerical value for the duration of a periodically repeating pulsed signal. This method comprises the following steps: a) at time intervals, the period length of the signal is determined; b) at time intervals, a characteristic magnitude for the length of a pulse of that signal is determined; c) a numerical value that characterizes the signal is ascertained from the period length and the characteristic magnitude. Because of its shortness and accuracy, the method is particularly suitable for use in electric motors. A corresponding arrangement is also presented and described.

Method for determining the numerical value for the duration of a periodically repeated pulse signal, and device 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

The invention relates to a computer-controlled electronically commutated motor (ECM) and to an improved method for processing data therein. The computer's program executes the steps of: a) defining, in recurrent steps, the rotor position region in which a current pulse is to flow through the at least one winding phase, and the duration (TCurr) of that current pulse; b) sensing, in recurrent steps, the rotation-speed-dependent time period (TPP) required by the rotor to pass through a predetermined rotation angle range; c) monitoring the ratio between that rotation-speed-dependent time period (TPP) and the duration (Tcurr) of the current pulses; and d) as a function of the magnitude of that ratio, choosing a time to perform, in the computer, at least one predetermined calculation, either during (Flag_Fct_Within=1) the duration (TCurr) of a current pulse or in a time span outside (Flag_Fct_Within=0) a current pulse. As a result of this judicious time allocation, even an inexpensive computer can perform both commutation control and other calculation tasks without time conflicts.

Method for processing data for an electronically commutated motor and 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

When digitizing a voltage, a capacitor is charged, through an impedance, to a voltage value (Um) dependent on the voltage to be digitized. The limits of that one of a plurality of voltage ranges in which said voltage value (Um) lies, are ascertained, and the two limits of that voltage range are defined as a first limit and second limit; the voltage at the capacitor is modified to the first limit by a charge modification circuit containing an impedance, and a first time interval needed therefor is identified; the voltage at the capacitor is modified to the second limit; the voltage at the capacitor is modified from the second to the first limit via the charge modification circuit. A seond time interval needed therefor is identified. Based on values of the first time interval and second time interval, a digital value is calculated, which serves as an indication of how much the voltage value (Um) at the capacitor differs from one of said two limits.

Method and apparatus for digitizing a voltage

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

In a method for commutating an electronically commutated motor, a predictive calculation is made of a first time span that the rotor will need in order to pass through a specified rotation angle that lies between a first rotational position (&part;0) and a later second rotational position (&part;1) at which a switching operation is to be effected in the motor. Upon actual passage through the first rotational position, a reference time is identified and stored. The time difference between the present time and the stored reference time is then monitored repeatedly and compared to the first time span; and when a specified relationship exists between the time difference and the first time span, the switching operation is performed.

Growing community of inventors

St. Georgen, Germany

Hans-Dieter Schondelmaier