A method of compensation of the frequency dependent systematic error of the time-division watt-converter using two multipliers

Abstract

The paper presents an original method for the compensation of the frequency dependent systematic error of the time-division multiplier (TDM). The method is based on two identical multipliers working at different conversion frequencies. Full compensation of the error can be achieved using simple calculation taking into account only the values of the output signals of the multipliers and the ratio of the conversion frequencies. It has been shown theoretically, by computer simulation that error of the method is less than +50/spl times/10/sup -6/ in the input signal frequency range up to one tenth of the lower conversion frequency. For the practical realization of the method there is no need to use two complete TDMs, but some simplifications are possible. Applying these simplifications a prototype watt-converter based on this method has been developed and results of measurements show that precision of +/-50/spl times/10/sup -6/ is achieved in the input frequency range from 50 Hz to 10 kHz if the lower conversion frequency is only 100 kHz.