第 26 卷 第 16 期 2006 年 8 月 文章编号:0258-8013 (2006) 16-0097-06
中 国 电 机 工 程 学 报 Proceedings of the CSEE 中图分类号:TM921 文献标识码:A
Vol.26 No.16 Aug. 2006 2006 Chin.Soc.for Elec.Eng. 学科分类号:47040
抛物线法 PWM 电流控制新技术
王广柱
(山东大学电气工程学院,山东省 济南市 250061) A Novel PWM Current Control Technique Using Parabola Function
WANG Guang-zhu
(School of Electrical Engineering, Shandong University, Jinan 250061, Shandong Province, China)
ABSTRACT: A new nonlinear current control technique is proposed, which is called "parabola PWM" method here, in which the current ripple is compared with a parabolic wave with reset to make the actual current track the reference current continually each cycle, and maintain the switching frequency to be nearly constant for a voltage-fed PWM converter. The shape of the parabolic wave depends on the difference between the ratio of time to the switching period and the square of the ratio, and its amplitude is in direct proportion to the switching period and dc bus voltage, and is in inverse proportion to the inductance. Steady state and dynamic stability study for the proposed "parabola PWM" current control scheme is presented. The results show that the control scheme with fixed switching frequency tends to bring a sub-harmonic oscillation, and the improved scheme by comparing the current ripple with a positive and a negative parabolic wave has stability in the large. Several circuitries for implementing the proposed "parabola PWM" method are provided. Simulation and experimental results verify the effectiveness of the new current control method. KEY WORDS: power electronics; voltage-fed PWM converter; current control; parabola function; switching frequency 摘要:给出一种用于电压型 PWM 变换器的非线性电流跟踪 控制方法——"抛物线"法,该方法采用一种带复位的抛物 线波形与电流跟踪误差直接比较, 产生开关频率基本恒定的 PWM 信号,能在一个开关周期内使变换器电流精确跟踪电 流指令值. 该抛物线波形的形状由时间与开关周期之比减去 该比值的平方决定, 其幅值与开关周期及主电路直流侧电压 成正比,与串联电感成反比.详细分析了该方法的动静态稳 定性, 结果表明采用固定开关频率的方法容易产生次谐波振 荡,而采用双向抛物线函数的改进方法具有较好的收敛性.
给出了该方法的多种电路实现方案. 仿真和实验验证了该方 法的有效性. 关键词:电力电子;电压型 PWM 变换器;电流控制;抛物 线法;开关频率

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