Unified PWM technique for real time power conversion

In this paper, a new voltage modulation technique named 'unified PWM (pulse width modulation)' is described for high performance voltage generation in a 3-phase voltage-fed inverter. By considering the operation of the inverter, a simple but useful concept named 'effective time' could be established, and, fully employing this concept, a new voltage modulation technique is presented with detailed explanation and actual test results. The results show that (1) the implementation burden of PWM is conspicuously reduced, (2) change from one modulation scheme to another is also obtained easily and seamlessly, and (3) widely used overmodulation schemes are easily implemented.