电工技术学报2026，Vol.41Issue(3)：738-748,11.DOI:10.19595/j.cnki.1000-6753.tces.250310
基于三相Buck整流器直流链电流纹波特性的最优三段式不对称空间矢量脉宽调制技术
Optimal Three-Segment Asymmetric Space Vector Pulse Width Modulation Technique Based on the DC Chain Current Ripple Characteristics of Three-Phase Buck Rectifier
摘要
Abstract
The input current total harmonic distortion(THD)of a three-phase buck rectifier is closely related to the modulation strategy.Space vector pulse width modulation(SVPWM)is widely used in three-phase buck rectifiers due to its simple digital implementation and flexible strategy.The three-segment asymmetric SVPWM has two different PWM sequences,which are generally considered to have equivalent vector synthesis effects.However,due to the influence of parasitic capacitances,the order of vector action affects the harmonic composition.Under the same input voltage conditions,these two asymmetric PWM sequences exhibit different DC chain current ripple characteristics.In addition,when the phase sequence of the input voltage changes,the corresponding DC chain current ripple changes accordingly,which leads to significant differences in the input currents of the three-phase buck rectifier.To deal with above issues,this paper proposes a phase sequence adaptive modulation strategy,which suppresses the DC chain current ripple and input current distortion caused by the asymmetry of the modulation technology. This paper analyzes the operating modes of the two asymmetric PWM sequences in sector 12 when the input voltage is in positive phase sequence,the changes of the difference between the upper and lower inductor currents,the charging and discharging conditions of the parasitic capacitances Cps and Cns,and derives the formula for the input current.The analysis and derivation results show that there are significant differences in the DC chain current ripple characteristics of these two asymmetric PWM sequences and their impacts on the input current.When the input voltage is in positive phase sequence,compared with the asymmetric PWM sequence 1,the DC chain current and its ripple of the three-phase buck rectifier with the asymmetric PWM sequence 2 increase significantly.When the input voltage is in negative phase sequence,the asymmetric PWM sequence 2 has more advantages.For asymmetric modulation technology,the DC chain current and its ripple of the three-phase Buck rectifier are significantly affected by the phase sequence of the input voltage,and the change of phase sequence will cause obvious distortion of the input current. This paper optimizes the phase shift in the digital implementation process and proposes a phase sequence adaptive modulation strategy to realize the logical matching between the input voltage phase sequence and the PWM sequence.To verify the analysis results,a 1 kW experimental prototype is designed.The experimental results show that when the asymmetric PWM sequence 1 modulation strategy is adopted,the input current THD of the three-phase buck rectifier is low(1.2%)under positive phase sequence input,while the input current is obviously distorted with a THD of 3.3%under negative phase sequence input.With the proposed phase sequence adaptive modulation strategy,both the DC chain current ripple and input current of the three-phase buck rectifier have no obvious distortion under either positive or negative phase sequence input,and the input current THD is low(1.2%)in both cases.In addition,when the input voltage phase sequence is unknown,the system can judge the input voltage phase sequence according to whether the sector is increasing and change the PWM sequence accordingly to achieve adaptation,thus suppressing the DC chain current ripple and input current distortion.关键词
三相Buck整流器/不对称调制/直流链电流纹波/输入电流畸变/输入相序Key words
Three-phase Buck rectifier/asymmetric modulation/DC chain current ripple/input current distortion/input phase sequence分类
信息技术与安全科学引用本文复制引用
陈欣,谢飞,许建平..基于三相Buck整流器直流链电流纹波特性的最优三段式不对称空间矢量脉宽调制技术[J].电工技术学报,2026,41(3):738-748,11.基金项目
国家自然科学基金资助项目(52477198). （52477198）
