摘要
在三相PWM整流器中,LCL滤波器很好地抑制整流器的开关纹波电流和纹波电压,减少对电网的谐波污染,然而,使用LCL滤波器会影响系统稳定性。提出了一种将系统数字控制中的零阶保持器和一拍控制延迟环节用于PWM整流控制的方法,在分析了LCL滤波的PWM整流器数学模型基础上,对PWM整流器的传递函数进行了离散化,应用Z平面上的根轨迹来分析PWM整流器的稳定性问题。而且通过对电流传感器进行位置调整,反馈量采用并网电流,不需要在滤波电容里面再串联电阻,也不要求把其他的反馈量引进来,便可使PWM整流器稳定运行。把系统传函从S域映射到Z域中,通过分析得出了系统闭环传函的根轨迹,理论上验证了所提方案的有效性,开发了套功率为180k W的PWM整流器装置,实践上验证了所提方法是正确而有效的。
In three-phase voltage source PWM rectifier, LCL filter has also brought problems of system stability, while LCL filter can well suppressed rectifier high-frequency ripple current and ripple voltage, and can reduce rectifier harmonic pollution effectively. Utilizing the zero-order hold and one shot control delay in digital control effectively, instead of feedback the current of rectifier, the grid current is used as the feedback. The direct current control scheme is adopted for the PWM rectifier, without the resistor in series with the filtering capacitor, and also do not need to add an additional amount of feedback, the PWM rectifier can run stably. The transfer function of the system is mapped from the S domain to the Z domain, then the root locus of the closed loop discrete transfer function is used to analyze the feasibility of the proposed method, At last, a prototype of 180 k W three-phase voltage source PWM rectifier is established. The analysis is validated in experiment.
出处
《控制工程》
CSCD
北大核心
2016年第10期1492-1496,共5页
Control Engineering of China
基金
湖南省科技计划项目(2012GK3079
2012GK3080)
湖南省高校创新平台开放基金项目(12K126)
