【作者】 张旭；

【导师】 于泳；

【作者基本信息】 哈尔滨工业大学 ， 电气工程（专业学位）， 2019， 硕士

【摘要】 高速加工作为一种国家战略性关键技术,代表着我国工业自动化水平,对我国完成产业转型与升级具有重要意义。感应电机由于其高可靠性、经济性、以及更好的弱磁升速能力而在高速加工领域得到了广泛应用。现今,高精密工业场合对生产工艺和效率要求更加严苛,不但需要主轴驱动系统具有极高转速运行能力,又对阶跃起停时间、动态控制、高速带载、无传感器运行等关键技术指标提出了更高的要求,造成现有的感应电机弱磁升速理论在高端加工领域逐渐显现出其局限性。本文深入探究了感应电机弱磁控制机理,在弱磁区最大转矩输出理论基础上,揭示电压拓展与转矩提升的内在关系,在保持系统高鲁棒性的同时,实现了包括动态响应速度、最大带载能力、电流控制性能等一系列指标的实质性提升。论文具体内容如下:首先,针对感应电机驱动系统中的最大电压、最大电流、以及最大转差造成的转速提升限制,对弱磁升速下的最大转矩控制机理展开研究。推导全速域内理论最大转矩输出下的电压电流矢量运行轨迹,根据轨迹特点,通过在传统双闭环控制结构内引入电压控制外环而实现精准的电压电流极限控制。分析比较电压闭环弱磁方法与传统转速反比法的优缺点,通过仿真实验对比了二者的控制效果,结果显示电压闭环法在最大转矩输出、加减速性能指标上的优势。其次,为了进一步提升弱磁区内系统输出最大转矩,针对传统内切圆电压下的电压浪费现象,通过六边形的电压边界拓展实现常规空间矢量调制方式下的逆变器分段线性区电压全部利用。接着,将弱磁控制闭环与定向环节视为一个整体,揭示了给定电压矢量的幅值与相位的控制独立性是保证实际电压精确跟随的必要条件,并基于此对传统六边形给定方法中电压矢量幅值与相位的耦合机理进行分析,探索传统方法中幅值-相位耦合造成时间延迟与相位滞后并最终导致六边形顶点电压缺失的问题。针对性的提出无相位滞后的标准六边形电压输出策略,通过引入过调制一区算法实现完整六边形电压拓展。最后通过实验分析并证明理论的优越性与优化算法的可靠性。再次,在六边形电压拓展的基础上,为实现弱磁区转矩的极限提升,通过引入过调制二区算法实现了弱磁区六拍运行。为分析六拍下电压非线性拓展与转矩提升的关系,根据六拍运行下电压矢量跳变规律,提出同步旋转坐标系下的感应电机新型等效电路,并基于该电路完成六拍模式下的转矩提升与转矩谐波的定量分析,证明了通过引入六拍实现转矩提升的可行性。基于理论分析结果,针对六拍模式下电流六次谐波过大的情况,对原有电流环与新增的谐波环展开分析,基于广义二阶积分器设计出不影响电流环带宽的谐振滤波器。最后通过对比实验验证了六拍运行模式下的转矩提升与所设计滤波器的滤波效果。最后,针对六拍运行模式下的电压裕量过小造成的电流动态性能下降问题,根据感应电机暂态电压模型,对电压裕量与动态电流控制间的作用机理展开深入分析。接着,把关注点放到了电流控制性能最差的弱磁过渡区,对过渡区内电流调节器过饱和失控的根本原因展开研究,揭示系统是通过弱磁控制最终实现退饱和的本质,并提出新型的非线性Anti-windup结构。进一步为实现弱磁区内的无速度传感器运行,将全阶磁链观测器引入到感应电机弱磁控制系统中,基于Lyapunov稳定性理论推导转速自适应率,通过结合了“预测-校正”的前向Euler离散化法得到离散域全阶磁链观测器,保证弱磁区内电机转速的准确观测。实验结果表明,过渡区内电流控制性能得到增强,同时无速度传感器算法在带载与高速等极端工况下是可靠的。更多还原

【Abstract】 As a national key strategic technology,high-speed machining represents the level of industrial automation in China and is of great significance to industrial transformation and upgrading.Induction motors are widely used in high-speed machining due to their high reliability,economy,and strong field-weakening speed extension capability.Nowadays,high-precision industrial applications require more stringent production processes and efficiencies.Not only do spindle drive systems require extremely high speed operation,but also key technical indicators such as step acceleration and braking times,dynamic control,high-speed loading,and sensorless control.Higher requirements have been put forward,which has led to the limitations of the existing induction motor field-weakening theory in high-end manufacturing industry.In this paper,the field-weakening control mechanism of induction motor is deeply explored.Based on the maximum torque theory,the inherent relationship between voltage expansion and torque extension is revealed.The dynamic performance,the maximum loading capacity,and the current control performance are optimized.Meanwhile,the high robustness of the system is maintained.The specific contents of the paper are as follows:Firstly,the maximum voltage,maximum current,and maximum slip frequency constrains in field-weakening region are studied in this paper.The voltage and current vector trajectories are derived.Along the trajectories,the maximum torque output can be realized in theory.To control the voltage and current vector move along the theoretical trajectories,the voltage closed-loop is introduced to the traditional induction control system.The advantages and disadvantages of the voltage closed-loop field-weakening method and the traditional“1/ω_r”method are analyzed and compared by simulation experiments.The results show that the voltage closed-loop method has obvious advantages in the maximum torque output and acceleration/braking performance.Further to increase the maximum torque in field-weakening region,the voltage utilization of the traditional inscribed circle voltage is extended to hexagon.And then the piecewise linear region can be fully used under hexagon voltage.Then,the voltage loop and the field orientation are regarded as a whole section.Based on this assumption,the following conclusion can be drawn:the independence control of the voltage amplitude and voltage phase is the necessary condition for accurate controlling of the voltage vector.Based on this analysis,the coupling mechanism of voltage vector amplitude and phase in traditional hexagon method is revealed.And the time-phase delay can be caused by the amplitude-phase coupling,which leads to the absence of hexagonal apex voltage.To solve problem,a standard hexagonal voltage output strategy without phase delay is proposed in this paper.By introducing the overmodulation one-region algorithm,a whole hexagonal voltage is realized in field-weakening region.The correctness of the theory and the effectiveness of the optimization algorithm are analyzed and verified by experiments.After that,on the basis of the hexagonal voltage,the six-step operation is introduced to the system for extreme torque extension.And the overmodulation two-region algorithm is combined to the SVPWM module.In order to analyze the relationship between voltage nonlinear expansion and torque extension under six-step operation,a new equivalent circuit of induction motor in synchronous rotating coordinate system is proposed according to the voltage vector jump rule in d-q frame.The effectiveness of the torque extension in six-step mode is confirmed by the quantitative analysis of torque extension and torque ripple.The relationship between the original current loop and the newly harmonic loop is analyzed independently.To cut off the main current harmonic(6th harmonic),a second-order generalized integrator(SOGI)-based band-stop filter is designed for the feedback current in the current loop.The designed filter can achieve IM stable operation in six-step mode without effecting the bandwidth of the current loop.Finally,the improvement of the system and the filtering effectiveness of the designed filter are verified by comparison experiments.Finally,aiming at the degradation of current dynamic performance in six-step mode,the relation between voltage margin and dynamic current control is analyzed according to the transient voltage model of induction motor.Then,the focus is placed on the transition field-weakening region when the worst current control performance happens.The root cause of the uncontrolled current in the transition region is studied.A new nonlinear anti-windup structure is proposed.Since the anti-windup operation is finally realized by field-weakening control,the d-axis voltage margin is prior in the proposed method.Futher to achieve the sensorless control in field-weakening region,the full-order flux observer is introduced to the system.The speed adaptation rate is designed based on Lyapunov stability theory.The discrete-domain full-order flux observer is obtained through the"prediction-correction"-combined forward Euler discretization method.The experimental results show that the current control performance in the transition region is enhanced,and the sensorless algorithm is reliable under extreme conditions such as load and high speed.更多还原