Danfoss A/s

Pentair Water Pool and Spa, Inc.

Danfoss Compressors Gmbh

Danfoss Drives A/s

Powerlynx A/s

Nils-Ole Harvest

Lars Hoffmann Berthelsen

Kevin Murphy

Ronald B Robol

Gert Kjaer

Peter Westermann-Rasmussen

Daniel J Hruby

Everett Franklin Cox

Donald Steen

Christopher Ryan Yahnker

Robert W Stiles, Jr

Florin Lungeanu

Einar Kjartan Runarsson

Arne Fink Hansen

Alberto Morando

Walter Woodcock, Jr

Uffe Borup

Robert Stiles

Aksel Baagoe Jepsen

Anna Melamed

Kenneth Skaug

Michael Toennes

Egon Krogh

Andreas Aupke

Jan Aarestrup

Jorgen Rasmussen

A pumping system includes a pump for moving water. In one aspect, this is in connection with performance of an operation. The system includes a variable speed motor operatively connected to drive the pump. A value indicative of flow rate of water is determined and the motor is controlled to adjust the flow rate indicative value toward a constant. A value indicative of flow pressure is determined and the motor is controlled to adjust the flow pressure indicative value toward a constant. A selection is made between flow rate control and flow pressure control. In another aspect, the pump is controlled to perform a first operation, and is operated to perform a second water operation. Control of operation of the pump to perform the first water operation is altered in response to operation of the pump to perform the second operation.

Control algorithm of variable speed pumping system

A mechanism is described for determining whether or not a ground connection is properly earthed by determining whether or not a potential difference exists between a voltage measuring point and a ground connection. A first capacitor is connected between the ground connection and a first power line and a first duplicating capacitor (having the same capacitance as the first capacitor) is connected between the voltage measuring point and the first power line. If the determining step determines that the potential difference does not exist, then it is determined that the ground connection is not properly earthed.

Earthed connection detection

A power converter for converting energy from a green power unit as e.g. a solar cell into energy fed into the commercial grid is described. The object is to provide a versatile modularized power converter with eased access to control of the power switches. Another object is to improve the electrical efficiency. This is achieved by using an independent controller on a DC/DC module and an independent controller on a DC/AC module, whereby the two independent controllers communicate with each other and the outside world by means of a communication bus. Further, the DC/DC module of the power converter comprises a transformer which transfers energy from the DC/DC module to the DC/AC module. This design enables independent control of the modules and eases controllability of the power switches in order to suppress retroaction from pulsations generated on the mains when supplying energy to a single phase grid. Hereby the electrical efficiency of the power converter is increased. Also, an active snubber circuit is described which further increase the efficiency.

Power converter

The invention is directed to controlling an electric motor by means of a frequency converter. The frequency converter can be connected to one of several different mains voltages. According to the present invention, the maximum output power of the frequency converter, is limited when the actual mains voltage is lower than the maximum nominal mains voltage, for which the frequency converter is designed, and during the limitation the frequency converter controls the speed of the motor within a power range up to a limited maximum output power. This gives a genuine multi-voltage unit, which can be connected to a wide range of mains voltages.

Frequency converter for different mains voltages

A method and power supply device for generating a regulated direct voltage from an alternating voltage using a step-down transformer, a step-up transformer, an inductance coil and a control device that controls the transformer in a step-down or step-up transformation mode is disclosed herein. An inductance coil voltage measuring signal is compared with three limiting values (A, B, C), wherein A corresponds to zero, B lies between A and C and B and C correspond to the direct voltage. Switching from the step-down to the step-up transformation mode is effected when the increasing voltage measuring signal drops after reaching B and A is not reached again and increases to C instead. Switching from step-down to step-up transformation mode is effected when the decreasing voltage measuring signal increases after reaching A and B is not reached and drops to A instead. In the power supply device, the control device includes three comparators for comparing the limiting values (A, B, C) with the voltage measuring signal of a voltage measuring device, wherein at least B anc C are dependent upon regulation deviation.

Method and power supply device for generating regulated D.C. voltage from A.C. voltage

Method of speed control of compressor and control arrangement using the

An inverter circuit which converts d.c. from a d.c. source to single or multiple phase a.c.. Two semiconductor switching elements for each phase are connected in series between two poles of a d.c. source. A signal generator provides a pulse width modulated signal for operating the switching elements. Blocking elements are provided between the signal generator and the switching elements. A control circuit senses current flow at the a.c. output and selectively enables the blocking elements in accordance with the direction of the current flow to prevent short circuiting between the switching elements.

Inverter circuit and a method for controlling same

The invention relates to an AC voltage supplied rectifier circuit with a downstream smoothing capacitor. A prior art problem with this type of circuit was that the inductive impedance of the supply voltage caused a practically umdamped oscillation between the inductive supply impedance and the smoothing capacitor during start-up which caused the voltage to rise to about twice the stationary value. A rectifier circuit is provided which substantially prevents the over-oscillation having at least one controllable rectifier which brings the rectifier to a conductive state during the charging period of the smoothing capacitor over such a time that the output direct voltage of the rectifier circuit exceeds the momentary capacitor voltage by no more than a predetermined limited value.

AC rectifier circuit with means for limiting the rectified voltage

The invention relates to a stabilizing circuit for an inverse rectifier motor control which includes a D.C. voltage supply having a D.C. voltage regulator followed by a smoothing intermediate circuit. A frequency control circuit converts the supply voltage from the intermediate circuit to a frequency control voltage. Following the frequency control circuit is a generator for converting the frequency control voltage to control signals for the inverse rectifier motor control.

Stabilizing circuit for an inverse rectifier motor control

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Nordborg, Denmark

Nils-Ole Harvest