摘要
针对传统直接转矩控制方法转矩和定子磁链脉动大、开关频率不恒定等问题,本文在详细分析转矩脉动和定子磁链脉动数学模型的基础上,提出了一种基于占空比调制的模型预测直接转矩控制策略。该策略根据转矩和定子磁链的综合误差确定所选电压矢量的占空比,根据不同的控制目标,占空比的计算方法可分为最终值法、平均值法和有效值法,每种方法均给出了精确的数学模型并进行了对比分析。同时考虑到实际应用中控制延迟的问题,引入了模型预测控制方法对系统变量进行预测,提前一个采样周期计算出所需施加的电压矢量及其占空比。仿真结果表明,基于占空比调制的模型预测直接转矩控制可以有效地抑制转矩脉动和定子磁链脉动,且逆变器开关频率恒定,同时降低系统采样频率。
In order to solve the problems of traditional direct torque control(DTC) such as high torque ripple, high stator flux ripple and inconstant switching frequency, a model predictive direct torque control(MPDTC) strategy based on duty ratio modulation is proposed in this paper. The mathematical models of torque and stator flux slopes are presented, and the duty ratio of the selected voltage vector is determined according to the total errors of torque and stator flux. Three different methods to determine the duty ratio are presented based on different control objectives, namely DRM-final, DRM-mean and DRM-rms. The mathematical models are presented and the comparative evaluation is conducted through numerous criteria. Considering the control delay in practical application, model predictive control(MPC) is employed to predict the machine variables. Hence, the desired voltage vector and its duty ratio can be obtained one sampling interval ahead. The simulation results indicate that the torque ripple and stator flux ripple are reduced under the control strategy proposed while the switching frequency stays constant and the sampling frequency is also reduced.
出处
《电工技术学报》
EI
CSCD
北大核心
2014年第11期20-29,共10页
Transactions of China Electrotechnical Society
基金
国家自然科学基金(51077038)
河北省高等学校创新团队领军人才培育计划(LJRC003)
国家留学基金(201206700002)资助项目
关键词
永磁同步电机
直接转矩控制
占空比调制
模型预测控制
Permanent magnet synchronous machine(PMSM),direct torque control(DTC),duty ratio modulation(DRM),model predictive control(MPC)
