Patent ID: 7218015

Claim:
A method of providing a desired constant AC voltage to a variable load which is arranged remote of a voltage source, comprising the steps of: compensating for a voltage drop over an electrical supply line which connects the load to the voltage source by a compensation AC voltage, the compensation AC voltage being added to the desired constant AC voltage to determine an output AC voltage of the voltage source; connecting an ohmic load instead of the variable load via the supply line to the AC voltage source and measuring a total value of the output AC voltage |U full | provided by the voltage source, a total value of an AC voltage |U load | drop over the ohmic load, and a total value of the alternating current |I| which is conducted at that same time; determining a first constant C R from the measured values for the linear variation of the compensation AC voltage with the total value of the alternating current and cos(phi) from the measured values; once the constant C R has been determined, connecting the variable load instead of the ohmic load via the supply line to the AC voltage source; and varying the compensation AC voltage depending both on an absolute value of an alternating current conducted to the load and on a phase angle phi between the output AC voltage of the voltage source and the alternating current, wherein the step of varying the compensation AC voltage depending both on the absolute value of the alternating current conducted to the load and on the phase angle phi comprises the step of calculating the compensation AC voltage from two summands which are linearly dependent on the total value of the alternating current, and one of which additionally comprises the factor C R* cos(phi) and the other of which is additionally linearly dependent on sin(phi).