Dynamic Programming-Based Optimal Torque Control of InductionMachine

控制电机转矩的尝试导致了不同控制策略的发展，其中直接转矩控制(DTC)和直接自我控制(DSC)以及基于脉宽调制(PWM)的策略今天已为人所知。基于PWM的控制策略的缺点是逆变器不必要的额外开关操作和控制器对参数的高度依赖。DTC和DSC控制策略具有较高的转矩、磁链和电流纹波，但仅显示较低的开关损耗。有了这一提议，将开发一种控制电机的新方法。逆变器是否应该改变其开关状态将根据轨迹上的当前和未来状态变量来决定，该轨迹应该能够实现驱动系统的最佳行为。为了优化的目的，将最小化一个代价函数，该代价函数包含诸如磁链和转矩与其参考值的偏差、达到预定速度或位置的时间、开关事件的次数、逆变器和IM的损耗等加权参数。为了在合理的时间和精力内解决优化问题，将使用动态规划的方法。这种方法解决了未来状态(事件视界)数目可控的优化问题，从而实现了电气传动的实时控制器。因此，这种方法被称为动态编程转矩控制(DPTC)。根据这一建议，将通过控制感应电机来研究DPTC的潜力和好处(然而，该方法可以应用于任何类型的电机)。首先，仿真表明，与DTC或DSC等方法相比，DPTC具有巨大的潜力。

The attempts to control the torque of electrical machines have led to development of different control strategies where Direct Torque Control (DTC) and Direct Self-Control (DSC) as well as strategies based on Pulse Width Modulation (PWM) are known today. The drawbacks of control strategies based on PWM are the unnecessary extra switching operations of the inverter and high Parameter dependencies of the controller. The DTC and DSC control strategies suffer from high torque, flux, and current ripple, but show only low switching losses. With this proposal, a new approach for controlling electric machines is to be developed. Whether the inverter should change its switching state will be decided based upon the present and future state variables along a trajectory which should enable optimal behavior of the drive system. For optimization purposes a cost function will be minimized, which contains weighted parameters such as the deviation of flux and torque from their reference values, time to reach a pre-set speed or position, number of switching events, losses of the inverter and the IM etc. In order to solve the optimization problem within reasonable time and effort, the method of Dynamic Programming will be used. This method solves the optimization problem for a manageable number of future states (the event horizon) and therefore enables an implementation for real-time controller of electric drives. The method is therefore called Dynamic Programing Torque Control (DPTC). With this proposal, the potential and the benefit of DPTC will be investigates by controlling an induction machine (the method, however, can be applied to any type of electric machine). First simulations have shown the huge potential of DPTC compared with methods such as DTC or DSC.