Digital peak current mode control of isolated current‐fed push‐pull DC‐DC converter with slope compensation

Abstract

The isolated current‐fed push‐pull dc‐dc converter has some practical advantages such as improved cross regulation characteristics, reduced output noise, and good overall efficiency. Although detailed insight on this converter is available in the literature, the use of digital peak current mode with slope compensation control methodology has not been explicitly presented. This paper discusses digital peak current mode control of a current‐fed push‐pull converter with a novel double digital pulse‐by‐pulse current limiting scheme. Push‐pull topology is implemented on the primary side of an isolation transformer in a dc‐dc bidirectional converter. Achieving this control solution of isolated push‐pull converter is attractive especially in controlling battery power flow in smart micro‐grids. By using a digitally controlled push‐pull converter, the ability to change controller parameters and the use of droop control methods for storage are easier. Furthermore, current mode control provides capability of equal current sharing between parallel converters and eliminates the transformer saturation problem that is common in push‐pull topology. Using continuous time model of the converter, a Type II compensator is designed and implemented in discrete time domain. Digital slope compensation is applied to eliminate the high frequency oscillations caused by current feedback loop. The control method and slope compensation are implemented on STM32F303 mixed‐signal microcontroller. On‐chip analog comparator disabled the PWM output if the sensed current exceeds the reference current until next PWM cycle. The digital controller performance is confirmed by 13 W hardware implementation including fast transient response and stable operation.

Modified Active-Clamped Current-Fed DC–DC Push–Pull Converter

“…One can obtain the theoretical value of the resonant inductance from (2). However, one must also incorporate the leakage inductance of transformer HFT2 represented by L lkg into the physical design of the resonant inductor while using the value of L ref in (3) for this purpose. Considering that L lkg = 0.05•L m is a conservative estimate, a more accurate design results from measuring L lkg in the laboratory.…”

“…Among several topologies available in the literature for this purpose, the conventional dc-dc push-pull converter represents a simple solution that does not require isolated drivers, but the possible core saturation due to flux imbalance is of major concern [2]. Another important issue is that the voltage stresses on the active switches of the primary side are somewhat high, whereas the reverse recovery current through the secondary-side diodes causes high switching losses during turn-off in both voltage-fed and current-fed converters [3].…”

An Extensive Critique on Electric Vehicle Components and Charging Systems

“…When compared to a traditional three-phase architecture, the proposed configuration demonstrated reduced switching losses and good efficiency. For charging the EV, Ghalebani et al [101] used the PPC topology.…”

“…e conductive-based charging connection between EV and charging outlet is connected in three ways. HPWM QZBC [136] PWM MDIBC [137] PWM Isolated converter PPC [101] PWM FC [105] Fixed frequency PWM RC [110] Quasi-resonant PWM ZVSC [138] Enhanced PWM MPIC [132] Modified PWM (i) In the first case (Case "A"), the permanent connection cable and plugs are permanently attached with the vehicle. is type is used in a light vehicle.…”