Control circuit of four-switch buck-boost converter

Abstract

The invention discloses a control circuit of a four-switch buck-boost converter. The control circuit comprises a first comparator, a second comparator, a third comparator, a fourth comparator, a current sensor, a first voltage sensor, a second voltage sensor, a first gate, a second gate, a third gate, a bus voltage regulator, an average current regulator, a phase shift controller, a first subtracter, a second subtracter, a third subtracter, a first phase inverter, a second phase inverter, a third phase inverter, a fourth phase inverter, a fifth phase inverter, a sixth phase inverter, a multiplier, a first hysteresis device, a second hysteresis device and twelve driving circuits. The problem that traditional two-mode control is frequently switched between a boost mode and a buck mode is avoided by adopting double hysteresis loops; voltage gain adjustment of a boost-buck mode of the converter is realized through internal shift; the problems of relatively large inductance current ripples and relatively large switching tube current stress of traditional three-mode control in the boost-buck mode are avoided; and the control circuit has wide application prospects in the field of direct-current converters.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a control circuit of a four-switch buck-boost converter. Background technique [0002] With the increasing environmental problems, traditional power generation methods are increasingly unable to meet people's needs for environmental protection. New energy power generation occupies a certain place in the current power generation mode. The multi-port energy router can connect various energy sources such as photovoltaics and energy storage, which is conducive to the distribution network to realize local consumption of renewable energy, peak shaving and valley filling, and power quality. optimization. [0003] In a multi-port energy router, the energy storage interface unit usually uses a non-isolated bidirectional DC converter. Compared with the traditional bidirectional boost or buck converter, the four-switch buck-boost converter can match a wider battery voltage range....

AI Technical Summary

Problems solved by technology

[0003] In a multi-port energy router, the energy storage interface unit usually uses a non-isolated bidirectional DC converter. Compared with the traditional bidirectional boost or buck converter, the four-switch buck-boost converter can match a wider battery voltage range. However, there are working conditions where the voltages at both ends are close, which puts forward higher requirements for the control of the converter. When the voltage is close, the traditional buck-boost working mode is used to avoid frequent switching of FSBB between boost and buck modes, but it will increase the inductor current ripple and the current stress of the switch tube, resulting in increased loss

The document "A NonlinearState Machine for Dead Zone Avoidance and Mitigation in a SynchronousNoninverting Buck-Boost Converter" proposes to shift the phase of the two bridge arms of the FSBB converter by 180 degrees, and adjust the duty cycle of the diagonal switch to control the voltage gain. The inductor current w ripples, but causes the voltage ripple to increase

The literature "A Novel Low-Loss Modulation Strategy for High-Power Bidirectional Buck,Boost Converters" and "A Constant Frequency ZVS Control System for the Four-SwitchBuck–Boost DC–DC Converter With Reduced Inductor Current" control the two bridge arms The turn-on sequence realizes the zero-voltage switching (Zero-Voltage Switch, ZVS) of the switching tube, which reduces the current stress and switching loss of the switching tube, but requires a high-precision current zero-crossing detection circuit, and the control is complicated

Images