Abstract: The present disclosure refers to a method for controlling the speed of a reciprocating load motor, wherein the motor speed is a function of two input variables, namely a user defined speed set-point and a load dependent input variable. According to the disclosure, the load dependent input variable is a function of the motor current. The disclosure also refers to a variable frequency drive for controlling the speed of a reciprocating load motor, wherein the drive is programmed to perform the presently described method.

Abstract: A method for detecting low impedance condition at an output (15) of an electrical converter (10), a control unit (1000), a computer program product, and an electrical converter (10) are presented. The method includes determining (110) a first current value (I1(T1)) of a first current (I1), and a second current value (I1(T2)) of the first current (I1), and determining (120) a first current difference (?I1) between the first (I1(T1)) and the second (I1(T2)) current values, and comparing (130) the first current difference (?I1) to a first current difference threshold (I1_TH), and if the first current difference (?I1) is of predefined magnitude with respect to the first current difference threshold (I1_TH), such as higher, turning off (140) a first voltage (U1) driving the first current (I1), such as by switching off a corresponding switch or switches for applying the first voltage (U1) to the output (15).

Abstract: The present invention relates to a motor controller providing a dual-channel func-tional-safety (FS) safe-torque-off (STO) function when controlling a motor. The motor controller includes an inverter with low-side switches and high-side switches, a low-side gate drive connected to the low-side switches, a high-side gate drive connected to the high-side switches, a first functional-safety safe-torque-off circuit connected to the high-side gate drive and a second functional-safety safe-torque-off circuit connected to the low-side gate drive, and a non-reinforced high-voltage isolation barrier.

Abstract: A power electronic device comprising a grid side (L1, L2, L3) connected to a capacitor bank (2) is described, the capacitor bank (2) being connected to ground via a switch. Such power electronic device should be used in different types of grid with low costs. To this end a varistor (5) is connected in parallel to the switch.

Abstract: The present invention relates to a method for estimating individual phase resistance of a motor by means of an adjustable speed drive (ASD) while the motor controlled by the ASD is running and/or is at standstill. The motor is an asynchronous motor or a synchronous motor. The invention also relates to an adjustable speed drive for executing a corresponding method.

Abstract: A method for determining rectifier-stage output current and/or grid-side currents (iu, iv, iw) of a frequency converter (1) having a passive rectifier (3), an inverter (4), a DC-link with a DC-link inductor (Ldc) and a DC-link capacitor (Cdc) between the rectification stage (3) and the inverter stage (4) is described. In a frequency converter the current information for the grid-side currents (iu, iv, iw) should be obtained without a current sensor at the grid-side (2). To this end the method comprises the step of calculating a current in the DC-link (5) by using at least a voltage value (Urec) and characteristics of the rectifier (3) in the DC-link (5) and/or grid side currents to form a corrected current using the calculated current and a measured current or currents or a fraction of a measured current or currents, or a fraction of a measured current or currents.

Abstract: The present invention is directed at a pulse shift protection method for detecting a phase-to-phase short circuit in a drive for controlling electric motors, wherein the drive provides an output voltage to the electric motor, and wherein the instant, at which a short circuit detection function is executed, is chosen to minimize disturbance in the output voltage of the drive. The invention is also directed at a drive for controlling electric motors, said drive including a controlling portion for generating an output signal and an output portion connectable to an electric motor. The drive is provided for executing the above-mentioned pulse shift protection method.

Abstract: A circuit comprising a first power node for connection to a positive voltage of a DC link, a second power node for connection to a negative voltage of the DC link and a mid-point power node for connection to a mid-point voltage of the DC-link, the circuit further comprising a three-level neutral point clamped converter module and a brake resistor connection.

Abstract: The present invention refers to an air-cooled motor controller for controlling electric motors, comprising a heat-sink and a variable fan for cooling passive and active components of the motor controller by means of an air stream generated by the fan. The invention is directed towards a fan control means and a coupled fan control method for controlling the speed of the fan of the motor controller in response to the losses in both passive and active devices inside the motor controller.

Abstract: Embodiments of the invention provide a pumping system for at least one aquatic application. The pumping system includes a pump, a motor coupled to the pump, and a controller in communication with the motor. The controller is configured to store a timeout time value. The controller is also configured to initiate a pump priming process and subsequently initiate a timeout counter to begin counting a counter time value. The controller is configured to initiate a timeout interrupt routine that interrupts the pump priming process when the counter time value exceeds the timeout time value. The timeout interrupt routine includes shutting down the motor.

Abstract: A method for identifying the magnetic anisotropy of an electric rotary field machine comprising a rotor and a stator is described, the method comprising the steps of setting injection pulses of equal absolute values during an injection interval, detecting a respective current response in form of current difference vectors, and determining the anisotropy from the voltage vectors and current difference vectors. Such a method should allow identifying of magnetic anisotropy in a simple way. To this end, injection pulses in the three-phase domain are used.