Measuring output current of clocked half bridge circuit, e.g. for driving motor - adding sum of AC output current and semiconductor switch currents in one state to AC current is second state

摘要

The method of measuring the output current of a clocked half bridge circuit (2) involves measuring, adding and storing the current flowing through the semiconductor switch (2;3) and the a.c. output current in one state. The a.c. current is subtracted from the stored value and the difference used as the measurement result for the first state. The stored sum value is added to the a.c. current value measured in a second operating state and the result used as the measurement result for the second state. The summation is performed with a sign inversion. USE/ADVANTAGE - E.g. for use in motor drive circuits. Enables economical measurement of output current without using d.c. converter.