A new soft-switchingPWMscheme for a three-phase, ac–dc, step-down, unity power factor converter is described. The main advantage of the scheme is that it requires no additional hardware components to achieve a combination of zero current and voltage turn-off and zero and reduced voltage turn-on. The scheme relies on the repositioning of the PWM pulses within the carrier period to obtain natural commutation from one switching device to the next. The theoretical reduction in the total switching losses is mathematically shown to be 42% compared with the standard center-aligned PWM scheme used with the converter. A PSpice™ simulation of the new scheme reveals soft-wwitching waveforms. Practical results are given to support the simulation results and heatsink temperature rise results showa reduction in heatsink temperature rise for the new scheme compared to the old.
|Translated title of the contribution||A New Soft-Switching Technique Using a Modified PWM Scheme Requiring No Extra Hardware|
|Pages (from-to)||686 - 693|
|Number of pages||8|
|Journal||IEEE Transactions on Power Electronics|
|Publication status||Published - Sep 2001|