Apparatus for eliminating motor voltage reflections and reducing EMI currents
AssigneeAllen-Bradley Company, Inc.
InventorsGary L. Skibinski, Henrik B. Nielsen
Life of this patent
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Abstract
An apparatus for essentially eliminating transmission line reflected waves and standing waves and for reducing common mode transient currents for use with a three phase motor controller, the apparatus including a common mode choke in series with a filter network between an inverter and a motor, the filter including three inductors and three resistors, the inductors and resistors together forming three inductor-resistor pairs, each pair including an inductor in parallel with a resistor, each pair linked to a separate one of three transmission supply lines which link the inverter to the motor, values of the resistors and inductors selected according to transmission line theory.
Claims9
An apparatus for eliminating reflected line voltages on the supply lines of an AC motor, the motor having three stator windings, each stator winding connected separately to a voltage source by a first, second or third supply line, respectively, the voltage source supplying high frequency voltage pulses on each supply line, each supply line having a characteristic line impedance, the apparatus comprising:
- first, second and third electrically resistive elements positioned in series with the first, second and third supply lines between the source and the stator windings, respectively, each resistive element having an impedance which is between one-fifth and four-fifths the resistance of the line impedance each of the resistive element resistances being essentially identical;
- first, second and third inductors linked in parallel to the first, second and third resistive elements, respectively, to form first, second and third filter elements, respectively;
- and
- a common mode choke linked to each of the first, second and third supply lines.
Dependencies are inferred from the claim text.