Parallel Connected Converters with Interleaved Phase‐Shifted PWM Using a Common Carrier

ABSTRACT A novel interleaving approach for parallel‐connected dual three‐phase converters using a single unmodified carrier is introduced. This method simplifies implementation by adjusting the phase with an offset added to the reference signal, without altering pulse width modulation (PWM) timing. It effectively controls flux and circulating currents within coupled inductor cores. Conventional schemes face challenges such as high direct current (DC)‐offset in circulating currents, poor line‐voltage quality, and glitches in load currents. They also rely on multiple phase‐shifted carriers that require each leg to have its own carrier signal, adding synchronization complexity. While modern digital controllers can accommodate this, managing synchronization remains a challenge, especially for low‐cost controllers with limited PWM carrier generation. These limitations can restrict the number of parallel legs per phase, affecting scalability. The proposed approach overcomes these issues by using a shared carrier for all modulators and adjusting the reference signal to achieve the required phase shift, ensuring high‐quality line voltage and glitch‐free load currents while simplifying implementation. This approach enhances flexibility in phase shift and duty cycle control while eliminating DC‐offset in flux and circulating currents, reducing magnetic component size via a simple reference signal adjustment at zero‐crossing. Feasibility is validated across low and high frequencies through analysis, simulations, and experiments.