Delay Mitigation in High Frequency Dual Current Programmed Mode Control GaN-Based ZVS Inverter

Abstract

Control based modulation techniques such as Boundary Current Mode (BCM) modulation are used to achieve zero voltage switching (ZVS) and overcome the increased switching losses in power electronics operating at high frequency. A simple control approach to implementing BCM uses dual current programmed mode (DCPM) control, but this approach is highly susceptible to noise and propagation delays at high switching frequency. Propagation delays in the control network cause the inductor current to overshoot its reference by a margin which varies with the instantaneous inductor current slope. This overshoot results in increased losses and introduces low-frequency inductor current distortion, particularly in high switching frequency converters. This work addresses propagation delay challenges by tuning the current sensing circuitry to mitigate impact of sensing delay, resulting in an inherent cancellation of sensing delay without additional control complexity. This approach is simple to implement and offers a flexible current control design for BCM modulation. The operation of this proposed compensation technique is demonstrated experimentally in a GaN-based full bridge inverter.