13-segment carrier pulse width modulation method and system and related components

Abstract

The invention discloses a thirteen-segment carrier pulse width modulation method and system and related components, relates to the field of carrier pulse width modulation, is applied to a three-level converter, and comprises the following steps: sorting three instantaneous voltage values of a three-phase sine wave; according to the maximum voltage value, the intermediate voltage value and the minimum voltage value, determining a dual-modulation wave parameter of the corresponding phase; determining an upper modulation wave and a lower modulation wave of the corresponding phase according to the dual modulation wave parameter of each phase; and comparing the upper modulation wave, the lower modulation wave and the triangular carrier wave of each phase to generate a driving signal of the corresponding phase. The driving signal output by the modulation method can ensure that the phase voltage pulse width of a low modulation degree region is greater than the minimum switching time of a device, so that narrow pulses are effectively eliminated, the target voltage is accurately output, and the effects of reducing current harmonic distortion and improving neutral-point voltage self-balance of the three-level converter are achieved. In addition, only amplitude calculation is needed, and the method has the advantages of being simple in calculation and easy to implement.

Description

technical field [0001] The invention relates to the field of carrier pulse width modulation, in particular to a thirteen-segment carrier pulse width modulation method, system and related components. Background technique [0002] Due to the advantages of low voltage stress of power devices, good output power quality, and relatively simple structure and control, three-level neutral point clamped (NPC) converters, referred to as three-level converters, are used in grid reactive power. Compensation, rail transit, wind power generation, metallurgical mining and other fields have been widely used. figure 1 It is the main circuit topology of the three-level converter. [0003] The control core of the three-level converter is to control the switching state of each power device. When each power device switches according to the set driving signal, the three-level converter can output the set voltage vector, and then accurately output the target. When the power devices are not driven...

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Problems solved by technology

[0003] The control core of the three-level converter is to control the switching state of each power device. When each power device switches according to the set driving signal, the three-level converter can output the set voltage vector, and then accurately output the target. voltage, and when the power devices are not driven normally, the output voltage of the three-level converter will be distorted, and even the operation of the converter will be uncontrollable

However, in the area of ​​low modulation degree, the phase voltage pulse width of the existing carrier pulse width modulation method and space vector modulation method is relatively narrow, which cannot achieve the effect that the phase voltage pulse width is greater than the minimum switching time of the device, resulting in the output voltage amplitude Distortion and Current Harmonic Degradation

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