开关磁阻电机微步直接转矩控制系统的研究

发布时间：2018-11-02 10:01

【摘要】：开关磁阻电机具有结构简单、造价低廉、调速性能优越等优点,应用范围越来越广泛,但是电机固有的转矩波动大的缺点阻碍了其大规模应用。在借鉴其他控制方法的基础上,本文提出了一种新的抑制转矩波动的控制方法——微步直接转矩控制。本控制策略融合了微步控制、直接转矩控制、转矩分配控制三种控制思想。本文以8/6极四相开关磁阻电机为例,在分析每相绕组产生转矩的正负、大小、变化趋势等规律的基础上,把360°的机械角度周期划分为6个电角度周期,把每个电角度周期又细化分为8个区间,在每个区间内采取相应的控制方法进行控制,体现了微步控制思想。在每个区间内,四相绕组中总有两相绕组产生正向转矩、两相绕组产生负向转矩,电机运行时使产生正向转矩的两相绕组共同产生电机总输出转矩。但是两相绕组不是均衡的分担总转矩。为了减小即将关断或刚刚导通的绕组由于转矩-电流的严重非线性引起的转矩波动,该相绕组电流应维持在较小数值,这样该相绕组分担的转矩必然较小,而另外一相绕组转矩-电流非线性不严重,其电流和分担的转矩都较大,这样就减小了电机输出转矩的波动,体现了转矩分配控制思想；在反馈控制中,直接以电机的输出转矩作为反馈量,形成转矩闭环负反馈控制。根据转矩偏差与要调节相绕组的单位转矩调节电流的乘积,计算出要改变的相绕组电流值,进而定量的调节绕组电流,使电机输出转矩等于期望转矩,转矩调节的周期很短,能在一定程度上抑制转矩波动,体现了直接转矩控制思想。在simulink中搭建了仿真模型,对提出的微步直接转矩控制策略进行仿真验证,本策略确实可以有效减小电机的转矩波动。此外还制作了以DSP+CPLD为控制核心、IGBT和快恢复二极管为功率器件的电机控制器硬件,对提出的控制策略进行了初步的实验。
[Abstract]:Switched reluctance motor (SRM) has many advantages such as simple structure, low cost and superior speed regulation performance. Its application range is more and more extensive, but its large scale application is hindered by its inherent shortcomings of large torque fluctuation. Based on the reference of other control methods, a new control method of torque ripple suppression, micro-step direct torque control, is proposed in this paper. This control strategy combines three control ideas: micro step control, direct torque control and torque distribution control. In this paper, taking 8 / 6 pole four phase switched reluctance motor as an example, on the basis of analyzing the positive and negative torque, the size of each phase winding and the changing trend, the mechanical angle period of 360 掳is divided into six electric angle cycles. Each electric angle period is further divided into 8 sections, and the corresponding control method is adopted in each interval, which embodies the idea of micro-step control. In each section, there are two phase windings that produce positive torque, two phase windings produce negative torque, and the two phase windings which produce positive torque together produce the total output torque of the motor. But the two-phase winding is not a balanced share of the total torque. In order to reduce the torque ripple caused by the serious nonlinearity of torque current in the winding that is about to be turned off or just switched on, the current of the phase winding should be maintained at a lower value, so that the torque shared by the phase winding must be smaller. The other phase winding torque-current nonlinearity is not serious, its current and share torque are larger, thus reducing the motor output torque ripple, reflecting the torque distribution control idea; In the feedback control, the output torque of the motor is taken as the feedback directly, and the torque closed-loop negative feedback control is formed. According to the product of the torque deviation and the unit torque regulation current of the phase winding to be adjusted, the current value of the phase winding to be changed is calculated, and then the winding current is adjusted quantitatively, so that the output torque of the motor is equal to the expected torque, and the period of torque regulation is very short. It can restrain torque ripple to a certain extent and embodies the idea of direct torque control. The simulation model is built in simulink, and the simulation results show that the proposed strategy can effectively reduce the torque ripple of the motor. In addition, the hardware of the motor controller with DSP CPLD as the control core and IGBT and fast recovery diode as the power device is made, and the proposed control strategy is preliminarily tested.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM352

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