A control circuit of a four-switch buck-boost converter

Abstract

The invention discloses a control circuit of a four-switch buck-boost converter, including a first comparator, a second comparator, a third comparator, a fourth comparator, a current sensor, a first voltage sensor, and a second voltage sensor , first to third gates, bus voltage regulator, average current regulator, phase shift controller, first subtractor, second subtractor, third subtractor, first inverter, second inverter , a third inverter, a fourth inverter, a fifth inverter, a sixth inverter, a multiplier, a first hysteresis, a second hysteresis, and twelve drive circuits. The double hysteresis loop is used to avoid the problem of frequent switching between the boost mode and the buck mode of the traditional two-mode control, and the voltage gain adjustment of the buck-boost mode of the converter is realized by moving inward, avoiding the traditional three-mode control in the up-down mode. In voltage mode, the inductor current ripple is large and the switching tube current stress is large, so it has broad application prospects in the field of DC 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....

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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

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