Bidirectional Symmetrical Half-Bridge DC-DC Converter

The bidirectional symmetrical half-bridge DC-DC converter plays a critical role in photovoltaic energy storage systems, enabling flexible bidirectional power flow – it can boost photovoltaic energy for storage in batteries and buck battery energy for feedback to the DC bus. Its symmetrical topology significantly reduces voltage stress on switching devices, while achieving soft-switching characteristics through phase-shift control strategies, balancing efficiency and electromagnetic compatibility.

When modeling in Matlab simulation, several core aspects require special attention: First, construct the half-bridge circuit using ideal switching devices and implement phase-shift control logic through PWM generators. Second, embed mode-switching modules within the voltage-current dual closed-loop control to automatically determine energy flow direction based on bus voltage and battery SOC. Finally, simulate the impact of dead time on switching losses and validate the dynamic response of synchronous rectification. This model has verified smooth transitions from Buck to Boost modes and voltage stabilization performance under sudden load changes, making it particularly suitable for distributed energy coordination control scenarios in microgrid systems.

In practical applications, the transformer turns ratio can be adjusted to adapt to different voltage levels of energy storage units, while its symmetrical characteristics facilitate expansion into multi-module parallel systems. Future optimization directions include incorporating digital control algorithms to handle nonlinear loads and integrating MPPT to achieve maximum power tracking for coordinated photovoltaic-storage operation.