【作者】 杨金波；

【导师】 李铁才；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2011， 博士

【摘要】 与传统三相电机相比,多相电机具有低压大功率输出、容错能力强等优点,在船舰电力推进、电动汽车、航空航天等领域具有广阔的应用前景。随着电力电子技术和微电子技术的发展,电机的相数已不再是传动系统设计中的一个制约因素,多相电机驱动系统得到了越来越多的关注。论文以相移30°双三相永磁同步电机(PMSM)为研究对象,对多相电机的驱动控制技术进行了深入研究。论文首先通过坐标变换,得到了双三相PMSM在双d-q和矢量空间解耦(VSD)坐标系下的数学模型,并给出了基于两种模型的矢量控制策略。双d-q矢量控制等效于对两台三相电机的控制,VSD矢量控制将对电流的控制放在了两个相互正交的子空间中。通过对两种矢量控制策略的比较,指出在相同的控制参数下两者对转矩和转速的控制效果是一致的。由于VSD模型揭示了双三相电机多谐波子空间的特点,在保证转速控制性能的前提下,既可以采用四维电流控制以得到最小的定子铜耗,也可以采用二维电流控制以简化控制系统结构,电流控制更加灵活。其次,对双三相PMSM的脉宽调制(PWM)算法进行深入分析。传统两矢量空间矢量脉宽调制(SVPWM)具有更高的母线电压利用率但是注入谐波电压过大,而四矢量SVPWM只用于输出正弦电压,限制了其调制范围。针对以上问题,论文将四矢量SVPWM扩展到非正弦电压调制区,得到了和两矢量SVPWM同样的调制范围,同时降低了注入的谐波电压,进而减少了谐波电流。将四矢量非正弦电压SVPWM统一到双零序注入PWM中,提出三段式调制策略,将线性调制范围分为正弦电流调制区、正弦电压调制区和非正弦电压调制区。其中第一个调制区对应的是四维电流控制,后两个调制区对应的都是二维电流控制,这种调制策略在全调制范围内对母线电压进行了最优化利用。再次,研究了永磁同步电机的非线性控制策略。通过输出反馈线性化得到完全解耦的永磁同步电机线性化模型,在该模型下可以通过直接控制电压来控制电机转速。针对反馈线性化控制对电机参数较为依赖的问题,将终端滑模(TSM)控制策略应用到反馈线性化模型中,分别设计转速和直轴电流滑模控制器,推导出控制率并给出系统稳定性证明。为了降低滑模增益,减小抖振,设计扰动观测器并对观测到的扰动量进行补偿。仿真结果表明,基于扰动补偿的反馈线性化终端滑模控制提高了转速的动态性能且具有较强的鲁棒性。最后,针对多相电机具有多控制自由度的特点研究了电机缺相后的容错运行问题。多相电机在缺相后,不同的中线连接方式对应着不同的电流优化控制策略。根据不同的中线连接方式以及相应的电流约束条件,选定矢量空间解耦变换阵,建立一相和正交两相开路双三相永磁同步电机的VSD数学模型,将电机变量分别映射到与机电能量转换相关的d-q子空间和与机电能量转换无关的z1-z2-z3子空间中。提出基于VSD模型的双三相PMSM容错控制策略,通过在z1-z2-z3子空间中设定不同的电流参考值可以分别得到定子铜耗最小和定子电流幅值最小两种电流优化控制策略。仿真和实验结果验证了容错控制方案的有效性。更多还原

【Abstract】 Compared with conventional three-phase motor, multiphase motor has the advantages of large power output with low voltage, good fault tolerant ability. It is suited for some application areas, such as electric ship propulsion, electric vehicles and aircrafts. With the development of power electronics and micro-electronics, phase number is not a restriction in the system design. Multiphase drive system has attracted more and more attention. Dual three-phase permanent magnet synchronous motor (PMSM) which has two sets of three-phase windings phase shifted by 30 electrical degrees is chosen as research object. Its drive and control technique are deeply studied in this dissertation.Firstly, the models of dual three-phase PMSM are set up in the double d-q and vector space decomposition (VSD) reference frames. Two vector control strategies related to the two models are proposed. The double d-q vector control is equivalent to the control of two three-phase motors. In VSD model, the current is controlled in two orthogonal subspaces. The comparative analysis of the two strategies shows that they have consistent control performance of torque and speed when their control parameters have the same value. The VSD model indicates the features of multiple harmonic subspaces of dual three-phase motor, so its current control is more flexible. With the same speed control performance, VSD vector control strategy can use four-dimension current control to minimize stator loss or two-dimension current control to simplify the system control structure.Secondly, the pulse width modulation (PWM) algorithms for dual three-phase motor are analyzed. Conventional two-vector space vector PWM (SVPWM) has a high DC bus utilization, but the output voltage has large harmonics. The four-vector SVPWM is just used to produce sinusoidal phase voltage, so the DC bus utilization cannot reach to the highest value. Four-vector SVPWM is extended to the non-sinusoidal voltage range in this dissertation. It has the same modulation range as the two-vector SVPWM, but reduces the voltage harmonics in non-sinusoidal voltage range. So the current harmonics and stator loss can also be reduced. The four-vector non-sinusoidal voltage modulation algorithm is then integrated into double zero-sequence injection PWM and three-segment modulation is proposed. The total modulation range is divided into three segment, sinusoidal current range, sinusoidal voltage range and non-sinusoidal voltage range. The first is related to four-dimension current control and the last two are related to two-dimension current control. This modulation algorithm has an optimal utilization of DC bus in the whole modulation range.Thirdly, the nonlinear control strategy for PMSM is studied. A fully decoupled linear model of PMSM is obtained by output feedback linearization. In this model, the speed can be controlled by directly controlling the voltage. The performance of the feedback linearization control depends on the parameters very much. To solve this problem, terminal sliding mode (TSM) control is used to design the speed and direct current controllers. The control laws are deduced and the system stability is proved. In order to reduce the sliding mode gain and chattering phenomena, a disturbance observer is designed. The disturbance observed is then compensated in the control. The simulation results show that the feedback linearization terminal sliding mode control with disturbance compensation improves the dynamic performance of speed and has good robustness.Lastly, in connction with the feature of multiple control dimensions of dual three-phase PMSM, fault tolerant control strategies with open phases are researched. Different neutral connections correspond with different optimal current control methods when the multiphase motor has open phases. Vector space decomposition transformation matrixes are determined according to different neutral connections and their current constrains with one open phase or two orthogonal open phases. Then different VSD models are deduced. All the variables are projected into d-q subspace which has relation to the electromechnical energy convertion and the z1-z2-z3 subspace which has no contribution to electromechnical energy convertion. Vector control methods based on VSD models are proposed. By setting different current references in z1-z2-z3 subspace, two optimal current control methods of minimum stator loss control and minimum current magnitude control are obtained. The effectiveness of the fault tolerant control methods are confirmed by simulation and expermnet results.更多还原