Bidirectional high-frequency link AC-DC matrix converter and control method thereof

Abstract

The invention discloses a control strategy based on a high-frequency link AC-DC matrix converter (HFLMC). Both the grid side and the DC side adopt a double closed-loop control strategy including a direct power outer loop and a current inner loop, and an H-bridge converter at the DC side and a three phase-single-phase matrix converter (MC) at the grid side share the power outer loop. Firstly, basedon conservation of input and output power, the power outer loop is a direct current selective control loop, the power outer loop outputs an active current instruction value, and an MC modulation signal is obtained by means of feedforward decoupling via the current inner loop; secondly, the DC side current instruction value calculated by the power outer loop is compared with a detection value, andthe modulation pulse of the H-bridge converter is output via a current regulator; and finally, the direct control of the grid side and DC side current is realized. The DC side current is enabled to have small ripple, the grid side can realize unit power operation, and the DC side can realize constant power, constant voltage and constant current operation, which enables the control strategy to beapplicable to battery charging and energy storage of electric automobiles.

Description

technical field [0001] The invention relates to an electric vehicle charger, in particular to a bidirectional high-frequency chain AC-DC matrix converter and a control method thereof. Background technique [0002] A typical AC-DC topology is a PWM rectifier. The PWM rectifier has the advantages of less sinusoidal harmonics and small distortion of the grid-side current; controllable power factor of the grid-side; energy can flow in both directions; and fast dynamic response. When the PWM converter cannot meet the voltage required by the equipment, it is necessary to add a power frequency transformer on the input side of the PWM converter to meet the voltage required by the equipment, but the volume and weight of the system will increase. Based on this, introducing a high-frequency transformer into the converter not only achieves electrical isolation and outputs a wider range of voltages, but also achieves high frequency, thereby increasing power density and reducing the volu...

AI Technical Summary

Problems solved by technology

However, this type of converter has a two-stage structure, and there is an energy storage link in the middle, which will reduce the work efficiency, and the two-stage converter needs to be modulated and controlled separately, which increases the control complexity.

Aiming at the problems of low conversion efficiency and complex control caused by the isolated converter with two-stage conversion, it is urgent to implement isolation conversion with a topology with fewer conversion stages and simple control

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