All-digital soft switching control circuit of four-switch buck-boost bidirectional converter

Abstract

The invention discloses an all-digital soft switching control circuit of a four-switch buck-boost bidirectional converter, and belongs to the technical field of control of power electronic converters. According to the invention, the converter works in a critical conduction mode, and zero-voltage conduction of the switch tube can be realized in a full-load range. During boost operation, a PI controller forming a current regulator and a voltage regulator calculates the turn-off time of a switch tube, and keeps the turn-on time constant; during step-down operation, the PI controller calculates the conduction time of the switch tube and keeps the conduction time constant for a short time; on the basis, the dead time is dynamically adjusted according to the input and output voltage of the converter, so that zero-voltage conduction of all switching tubes is realized. According to the invention, a high-cost zero-cross detection circuit is omitted, the control is simple and easy to realize, the power density of the converter is improved, and the method has a wide application prospect in the field of power electronic converters.

Description

technical field [0001] The invention belongs to the technical field of control of power electronic converters. Background technique [0002] New energy power generation is an important way to change my country's coal-based energy structure and achieve the goal of carbon peaking in 2030 and carbon neutrality in 2060. The bidirectional buck-boost converter connected to the energy storage system in the new energy power generation plays an important role in the new energy power generation as the core equipment for stabilizing the fluctuation of the new energy output and stabilizing the voltage of the distribution network. [0003] A four-switch buck-boost bidirectional converter (Four Switch Buck-Boost, FSBB), its topology is as follows figure 1 shown. When the traditional pulse width modulation is adopted and the inductor current is continuous, the switching tube has a large switching loss due to the hard switching action, and when the switching frequency increases, it will s...

AI Technical Summary

Problems solved by technology

However, this control strategy requires an inductor current zero-crossing detection (ZCD) circuit and a large number of body diode conduction detection circuits, and the hardware cost is relatively high.

All-digital control can realize all functions through a low-cost digital controller, and is suitable for cost-sensitive fields such as energy storage system interface bidirectional buck-boost converters. However, there is still a lack of effective full-digital soft-switching control methods at this stage

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