SYSTEM AND METHOD TO ELIMINATE THE DEAD TIME INFLUENCE PWM-DRIVEN SYSTME

摘要

A system and method to eliminate the influence of Dead Time delay in a PWM driven system. The system is implemented using a switching control circuit to operate a pair of upper and lower switching devices in a standard half-bridge arrangement, wherein both a PWM pulse train input and the direction of current flow (current command direction) are both utilized to operate the switching devices. Depending on the direction of the current command, the PWN pulse train input is directly applied to control one of the switching devices (the first switching device), while the second switching device is kept open at least during the closing time of the first switching device. Thus, a precise average PWM output volgate can be obtained, independent of the Dead Time delay, so that a large Dead Time can be used, to provide a precise voltage output over the full range of the DC power supply, while maintaining high reliability. The system can also be implemented using a microprocessor-based control system, for control of the switching devices, for betetr integration in a digital system.