A wide-bandwidth current-controller is required for the fast charging and discharging of applications containing super capacitors. To accomplish this, peak current mode is generally used due to the speed of its response characteristics. On the other hand, peak current mode control must be provided with a slope compensation function to restrain sub-harmonic oscillations. However, if the controlled output voltage is varied, the slope must be changed accordingly. Nonetheless, it is not easy to change the slope for every change in output voltage. Another solution involves the slope being set at the maximum value, which results in a slow response. Therefore, in this paper, a hybrid mode controller was proposed that uses a peak current and a newly-specified valley current. Using the proposed hybrid mode control, sub-harmonic oscillation did not occur for duty cycles larger than 0.5 and response times were fast.

This paper proposes a newly developed hybrid current-mode control (HCMC) method for phase-shifted full-bridge (PSFB) converters. Generally, PSFB converters have been widely used in various DC-DC power applications owing to their ease of control and low switching losses. However, the transformer can be saturated by volt-second imbalance of the magnetizing inductance. Therefore, a blocking capacitor can be used in series with the transformer, or peak current-mode control methods with slope compensation can be applied, to prevent transformer saturation. However, blocking capacitors increase the material cost and make the power stage bulky. Moreover, the overcompensation by slope compensation methods delays the control response. This paper proposes a hybrid current-mode control (HCMC) for PSFB converters to solve these problems. A blocking capacitor and slope compensation are not required in the proposed HCMC method for PSFB converters. The proposed HCMC method has no transformer saturation and output response delay, and the efficacy of this method has been verified through simulations and experiments.