Power Device Temperature-Balancing Control Method for a Phase-Shift Full-Bridge Converter

Abstract

In this paper, a switching method is proposed for power device temperature-balancing in a phase-shift full-bridge (PSFB) converter. PSFB is commonly used for applications that require high efficiency, because a zero-voltage switching (ZVS) operation is possible on the primary-side. In PSFB, the circulation current complicates ZVS under a light-load condition, which generates heat. Meanwhile, the heat generated in PSFB creates a temperature deviation between the lagging leg and the leading leg, which shortens the lifetime of the power device, thereby reducing system reliability and efficiency. To solve this problem, previous studies applied a pulse-width modulation (PWM) switching method for light and medium loads, and a phase-shift switching method for the region where ZVS is possible. Although this method has the advantage of easy control, the maximum temperature of the legs of the PSFB increases with medium loads. In this paper, a temperature-balancing algorithm—a temperature-balance control—is proposed to decrease the leg temperature using switching based on position exchanges of the leading leg and lagging leg along with PWM switching. Temperature-balance control minimizes leg temperature deviation under light load conditions. The proposed control method provides a minimum temperature difference between the two legs and high efficiency.

Closed-Form Formulas for Automated Design of SiC-Based Phase-Shifted Full Bridge Converters in Charger Applications

“…For inductance L l , on the other hand, it is instrumental to know the instantaneous values at the beginning of the first four states (I Ll(I) , I Ll(II) , I Ll(III) , I Ll(IV) ). These parameters can be calculated based on the total current swing of the series-inductance current (∆i Ll ) and the partial increments obtained in ( 5), (12), and (18):…”

“…For that, one needs closed-form expressions, which enable a spreadsheet-or MATLABtype software to calculate various solutions quickly, based only on a closed set of design parameters. Some advanced mathematical models related to the output voltage and losses were presented in the literature; however, these concerned the two-diode PSFB version, which is suited for low-voltage applications [11][12][13][14][15]. Research was also performed in the area of the PSFB with a voltage doubler [16], and even though this topology is well-suited for high-voltage applications, it lacks in power throughput.…”