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。
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.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2006年第16期97-102,共6页
Proceedings of the CSEE
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
power electronics
voltage-fed PWM converter
current control
parabola function
switching frequency
