旋转导向钻井工具涡轮电机电磁转矩前馈控制

钻井液流量的大范围变动容易导致旋转导向钻井工具空间角度位置控制的适应性差，具体表现为系统在某钻井液流量条件下整定的控制参数，在其他流量条件下常常是不稳定的，出现角度的振荡摆动、控制失稳。通过对涡轮电机电磁转矩与钻井液流量和控制信号动态关系的分析，建立了涡轮电机的动力学模型，模型表明电磁转矩的大小与流量和控制作用的乘积有一定比例关系，电磁转矩随钻井液流量呈动态变化，从而导致了控制的失稳。基于此提出了一种乘积型电磁转矩电压前馈补偿方法，经过前馈补偿后的电机电磁转矩的大小只与控制作用相关，而与钻井液流量无关，从而将一个非线性时变环节变换成了一个线性时不变环节；通过仿真分析与台架试验均验证了该方法的有效性，为实现平台系统在钻井液流量宽范围变化条件下的稳定控制提供了一种简便有效方法。

Electromagnetic torque feed-forward control of the turbine alternator for rotary steering drilling tools

Variations in the flow of drilling fluid in a wide range would easily cause poor adaptability of spatial position control for rotary steering drilling systems. Specifically, the control system adjusted with a set of control parameters under one drilling fluid flow condition is often instable with sway position under other flow conditions. A dynamic model of turbine alternator is constructed by analyzing the dynamic relationship of the electromagnetic torque of turbine alternator with the fluid flow and control signal. Results show that the electromagnetic torque is a product of fluid flow and control signal; it varies with drilling fluid flow dynamically, thus leading to control instability. Further, a product-type electromagnetic torque feed-forward control method is proposed, in which the electromagnetic torque of turbine alternator after feed-forward compensation relates to control signal only but no longer to drilling fluid flow. In this way, a nonlinear time-varying section is transformed to a linear time-invariant one. The proposed method is validated by a series of simulations and a mechanic driving test. A simple and effective method is provided for stable control of rotary steering drilling systems with drilling fluid flow varying widely.