摘要
煤矿高效可靠生产运输的一种优选方案是采用井上变频-井下永磁同步电机长线驱动方式。长线缆会加剧电机过电压和绝缘老化,故需加装输出LC滤波器。LC滤波器增加了系统阶数,导致传统线性控制策略结构复杂且参数整定耗时。为此,该文提出一种永磁同步电机长线变频驱动系统的固定开关频率滑模预测电流控制(FSF-SPCC)策略。首先,建立基于滑模切换函数的预测模型,并设计基于滑模面跟踪的价值函数。因滑模面固有地实现了多变量控制,故可有效抑制谐振。其次,为了提升系统稳态性能并方便LC滤波器的设计,进一步提出一种三矢量FSF-SPCC控制器,实现了固定开关频率。最后,通过实验验证了所提控制策略的可行性。
To realize efficient and reliable production and transportation for underground coal mine mining applications, the inverters are generally placed above the mine, and the permanent magnet synchronous motors(PMSMs) are deployed underground and connected by long cables. Long cables will aggravate the over-voltage and the insulation aging of PMSMs. Thus, an output LC filter is necessary. Nevertheless, introducing LC filters increases the system order, leading to complicated control structures, time-consuming parameter-tuning efforts,and unsatisfactory steady-state performance. Therefore, this paper proposes a fixed-switching frequency sliding mode predictive current control(FSF-SPCC) scheme for PMSM long-cable variable frequency drive systems to improve the steady-state performance and robustness of the system.First, a linear sliding-mode switching function for stator-current tracking is designed, and a sliding-mode prediction model is built. Then, based on the ‘equivalent control’, a cost function based on sliding-mode surface tracking is designed. Since the sliding-mode surface inherently realizes the multi-variable control, the resonance is effectively suppressed, and the system robustness is significantly enhanced. Also, the delay compensation of the controller is considered to eliminate the performance degradation caused by the one-step computational delay of the actual digital controller. In addition, a three-vector FSF-SPCC controller is further proposed to improve the system’s steady-state performance and facilitate the LC-filter design. By simulating the principle of space vector modulation, two active vectors and one zero vector are employed simultaneously to synthesize the dead-beat solution based sliding mode voltage reference. Therein, the optimal voltage-vector combinations and corresponding duty cycles are determined by minimizing the weighted tracking errors of the reference voltage vector, which improves steady-state performance with a fixed switching frequency.Experiments are carried out based on an actual low-power PMSM long-cable drive system. Experimental results show that compared with the conventional PCC method, the proposed FSF-SPCC scheme can achieve lower stator-current ripples and total harmonic distortion(nearly five-fold decrease) at the rotor speed of1 000 r/min in the steady state. Since the proposed FSF-SPCC inherently controls two state variables, the resonance is suppressed, and the steady-state performance is enhanced. Moreover, the harmonic spectrum of the proposed method is concentrated at the switching frequency and its integer multiples, resulting in a constant switching frequency. Besides, speed regulation(from 500 r/min to 1 000 r/min) shows that the proposed method can obtain a similar dynamic response as the conventional PCC method. Changing ±50 % stator-inductance parameters shows that the proposed FSF-SPCC scheme is more robust to model mismatches than the conventional PCC method.The following conclusions can be drawn from the experimental analysis:(1) The proposed method designs a cost function based on sliding-mode surface tracking, which effectively simplifies the control structure,suppresses the resonance, and enhances the robustness.(2) A three-vector FSF-SPCC controller is further proposed, which employs three voltage vectors to synthesize the sliding-mode voltage reference. Hence, a fixed switching frequency is achieved, and the proposed method has a more compact output-filter design and better steady-state performance than the conventional PCC method.
作者
郑长明
阳佳峰
高昂
公铮
伍小杰
Zheng Changming;Yang Jiafeng;Gao Ang;Gong Zheng;Wu Xiaojie(School of Electrical Engineering China University of Mining and Technology,Xuzhou 221116 China;State Grid Zhenjiang Power Supply Company,Zhenjiang 212002 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2023年第4期915-924,共10页
Transactions of China Electrotechnical Society
基金
国家自然科学基金面上项目(52277205)
国家自然科学基金青年科学基金项目(51907196,52107217)
江苏省自然科学基金项目(BK20190630)资助。
关键词
永磁同步电机
长线驱动
滑模预测控制
固定开关频率
Permanent-magnet synchronous motor
long-cable drives
sliding mode predictive control
fixed switching frequency
作者简介
郑长明,男,1991年生,讲师,硕士生导师,研究方向为永磁同步电机控制、构网型变换器与柔性直流输配电系统控制。E-mail:jsxzzcm@126.com;通信作者:公铮,男,1990年生,副教授,博士生导师,研究方向为大容量功率变换拓扑及控制与柔性直流输配电系统控制及保护。E-mail:zgo@cumt.edu.cn。
