Pulse width modulation method, pulse width modulation system, and controller

Abstract

The invention provides a pulse width modulation method, a pulse width modulation system, and a controller. Thus, a three-phase inverter can select a modulation mode according to modulation parameters,a harmonic standard requirement is met while the normal operation of the three-phase inverter is ensured, and the stability of a three-phase inverter system is improved. The method in the embodimentcomprises steps: modulation parameters of the three-phase inverter are acquired, wherein the modulation parameters of the three-phase inverter comprise a degree of modulation and an operating parameter of the inverter, and the operating parameter is used for indicating the operating state of the three-phase inverter; when the modulation parameters meet a continuous pulse width modulation (CPWM) condition, CPWM is selected as the modulation mode of the three-phase inverter; when the modulation parameters meet a discontinuous pulse width modulation (DPWM) condition, DPWM is selected as the modulation mode of the three-phase inverter; and when the modulation parameters do not meet the CPWM condition or do not meet the DPWM condition, the modulation mode of the three-phase inverter during theprevious control period is selected as the modulation mode during the current control period.

Description

technical field [0001] The present application relates to the field of circuit technology, in particular to a pulse width modulation method, a pulse width modulation system and a controller. Background technique [0002] With the development of economy and society, the energy crisis has gradually become prominent and the global environment has gradually deteriorated. The development and use of clean alternative energy has become an important goal of the energy industry. With the continuous development of new energy power generation, energy storage and new energy automobile industry, the converter as the core energy control device has become one of the key factors for clean energy applications. [0003] Among many types of converters, three-phase converters are one of the most widely used converters, which are used to connect three-phase AC power systems and DC power systems and realize energy transfer between the two systems. According to the different direction of energy f...

AI Technical Summary

Problems solved by technology

[0006] However, the existing method 1 is only suitable for motor drive application scenarios, and cannot meet the requirements of high-power three-phase AC power systems and grid-connected DC power systems; while the existing method 2 is a protective method, and its purpose is to Solve the faults or abnormal problems during the operation of the converter, without considering the optimization of harmonic indicators, etc.

Moreover, the existing methods 1 and 2 only set a threshold value for a certain parameter (such as the modulation degree) to select the modulation method, which has certain hidden dangers in stability, that is, when the parameter is near the threshold value, due to sampling errors and control errors, etc. influence, it may fluctuate frequently above and below the threshold, thus switching the modulation mode frequently, which may lead to instability of the converter system

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