Hybrid control method and device of four-switch Buck-Boost converter

Abstract

The invention discloses a hybrid control method and device of a four-switch Buck-Boost converter. The hybrid control method comprises a digital control mode and an analog control mode and comprises the following steps of: respectively obtaining a digital control signal and an analog control signal according to an output voltage error signal in the working process; then generating a hybrid control signal according to the analog control signal and the digital control signal; when the load at the output end of the converter does not jump, adopting the hybrid control signal to control the switch motions of switch tubes in the converter so as to keep the output voltage at a constant value; and when the load at the output end of the converter jumps, adopting the hybrid control signal to control the switch motions of the switch tubes in the converter so as to rapidly restore the output voltage to the constant value. The hybrid control method and device have the characteristics of simple control scheme, high dynamic response speed and high steady state accuracy.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a hybrid control method and device for a four-switch Buck-Boost converter. Background technique [0002] The four-switch Buck-boost converter has always attracted people's attention due to its advantages of in-phase input and output, low switching loss, and output voltage can be increased or decreased. The optimal control strategy for its circuit has also become a current research hotspot. At present, the control scheme of this kind of circuit in domestic research is mainly analog control mode, and the analog control mode includes voltage mode and current mode. The voltage mode is relatively simple, mainly including an error amplifier and logic circuit, and the error amplifier has two inputs. The terminal respectively receives the output voltage sampling signal and a reference signal, and compares the output signal with a sawtooth signal, and then generate...

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Problems solved by technology

However, the disadvantage of this pure digital control method is that it does not take into account the situation in the steady state of the circuit. Due to the problem of quantization accuracy in the digital control circuit, the system may also have small disturbances in the steady state, such as the amplitude of the disturbance does not reach The threshold of digital quantization. At this time, the digital control system will not take action, so that the output voltage cannot be guaranteed to remain constant.

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