Control method for bidirectional DC-DC converter based on Z source

Abstract

The invention discloses a control method for a bidirectional DC-DC converter based on a Z source, and aims to provide a method for controlling the voltage rising and dropping of the converter within a wide range, short-circuit protection, energy flow control and the switching of forward-reverse energy flow. The technical scheme adopted by the invention is that a control unit in the converter is improved, so that the control unit consists of a voltage calculating unit, a voltage deviation calculating unit, a voltage controller, a current calculating unit, a current deviation calculating unit, a current controller and a failure monitoring unit, and then a double parallel closed-loop control method for performing single closed-loop control on electric current and voltage is adopted to control the energy flow of the converter. According to the invention, the control of output voltage rising and dropping within a large range is realized; the independent control of the electric current and the voltage, and the decoupling control of variates are realized; the smooth switching of energy flow can be realized without stopping the converter; the short-circuit failures of input and output can be rapidly judged, and failure protection can be rapidly performed.

Description

technical field [0001] The invention belongs to the field of bidirectional high-power DC-DC conversion, in particular to a control method for a Z-source-based high-power DC-DC converter. Background technique [0002] Bidirectional high-power DC-DC converters have broad application prospects in distributed power generation, electric vehicles, energy storage systems, new energy power generation and other fields. [0003] The dual active full-bridge topology is the preferred topology in the field of isolated high-power bidirectional DC-DC converters due to its small current / voltage stress on power devices and higher power transmission by devices with the same capacity. [0004] In the main circuit of the Dual Active Bridge Bi-directional Converter (DABBC for short), the active bridge on the primary side is composed of four switching power transistors to form a full bridge circuit, which works in the inverter state. The turn-on and turn-off are controlled by a PWM (Pulse Width ...

AI Technical Summary

Problems solved by technology

[0009] However, the control method published in the document "Z source bidirectional DC-DC converter and its phase-shifted direct control strategy" is a multi-input variable, multi-output control method, and the control method is fuzzy and complicated; Self-shifting the phase angle and inserting the through zero vector to adjust the output voltage and output current, and changing the phase shifting angle and inserting the through zero vector can affect the output voltage and output current, each input and output are coupled to each other, and the change of the phase shifting angle is not clearly described A method of mutual cooperative control and decoupled control of both interpolated thru zero-vector angles

And this method does not involve the control of the switching process of energy forward and reverse flow and the short circuit fault protection control method

Images