打开文本图片集
摘 要:针对混动电动轮自卸车(HMDT)电制动励磁控制非线性和负载干扰较大的时变不确定性,对整车稳定性特别是电池寿命的影响,提出一种反馈精确线性化控制与滑模控制相结合的非线性变结构控制(NVSC)励磁控制策略.建立电制动励磁控制SISO二阶非线性模型,对模型精确线性化处理;应用滑模变结构控制设计了转速闭环励磁控制器,考虑矿山恶劣工况下为了削弱系统抖振、保证车速和制动电流稳定,设计了Luenberger负载干扰状态观测器.MATLAB仿真与实验结果表明:NVSC控制器相比PID控制除了具有动态性能好、响应快等优点外,在负载干扰波动下,电机转速和制动回馈电流保持稳定,系统鲁棒性好,保证了HMDT电池寿命和整车稳定.
关键词:混动电动轮自卸车;励磁控制;非线性变结构控制;状态观测器
中图分类号:TP 13 文献标志码:A
Nonlinear Variable Structure Excitation Control for Electric Brake
of Hybrid Motor Dump Truck
XIA Yunqing1,2,TANG Huaping1?覮,TAN Qing1,ZHU Guanghui2
(1. School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;
2. Xiangtan Electric Machinery Co Ltd,Xiangtan 411101,China )
Abstract: As the uncertainty of the nonlinearity and load disturbance of the electric brake excitation control of Hybrid Motor Dump Truck (HMDT) impacts on vehicle stability, especially on battery life, a nonlinear variable structure excitation control strategy with feedback precision linearization control and sliding mode control was proposed. This paper established the Simple Input Simple Output(SISO) second-order nonlinear model of electric brake excitation control, and the nonlinear problem was transformed into a linear problem by the precise linearization of the nonlinear model. Then, the speed closed-loop excitation controller was designed with sliding mode variable structure control. At the same time, in order to weaken the system buffeting, ensure system stability under the bad working condition of the mine, and ensure stable speed and braking current, the Luenberger load disturbance state observer was designed. MATLAB simulation results show that, compared with PID controller, NVSC controller has the advantages of dynamic performance and quick response. Under load disturbance fluctuation, the motor speed and braking feedback current are stable and the system is robust, which guarantees the battery life and HMDT stability.
Keywords:Hybrid Motor Dump Truck(HMDT);excitation control;Nonlinear Variable Structure Control(NVSC);state observer
大吨位(≮100T)混合动力电动轮自卸车(hybrid motor dump truck,HMDT)在國内外属于新型车型,不同于电制动回馈能量由制动电阻消耗的传统电动轮自卸车,HMDT的电制动回馈电流为车载电池系统充电,电池系统再适时为车辆提供补充功率,并以此循环. 一般电制动励磁控制是指对制动工况下牵引电动机的励磁进行闭环调节,并保证车辆有足够的制动力和制动过程平缓,限制制动电流以保护牵引电动机并实现对车速的理想控制[1-3].
而HMDT的电制动励磁控制系统还需考虑过大的充电电流引起电池过热,影响电池寿命[4],由于电动轮自卸车吨位大,电制动功率相差6~7倍的变化与矿山3%~18%坡道的变化等恶劣工况,都会引起负载干扰较大的时变不确定性,HMDT电制动励磁控制系统如果不能及时响应和抑制突增干扰,极易引起制动电流(充电电流)过载.