This paper presents a state‐dependent self‐tuning fractional control strategy for a DC‐DC buck converter in order to enhance its output voltage regulation and disturbance attenuation capability. The proposed control scheme primarily employs a ubiquitous proportional‐integral‐derivative (PID) controller, where gains are optimally selected using a linear‐quadratic state‐space tuning approach. The optimal PID controller is then augmented with fractional‐order integral and derivative operators in order to improve the controller's degrees‐of‐freedom as well as the system's overall time‐domain performance. The fractional controller's robustness against bounded exogenous disturbances, contributed by the input fluctuations and load‐step transients, is further enhanced by adaptively modulating the fractional‐orders of the integro‐differential operators as a smooth nonlinear function of controlled‐variable's error‐dynamics. An online dynamic adjustment law, comprising of a zero‐mean Gaussian function of error and its derivative, is used to individually update the two fractional orders after every sampling interval. The error derivative is evaluated by measuring the output capacitor's current in order to compensate the noise injected by parasitic impedance. The other controller parameters are tuned via particle‐swarm‐optimization algorithm. The proposed self‐adaptive control strategy renders rapid transits, minimum transient recovery time, and minimal fluctuations around steady state in the response. Its efficacy is validated through hardware in‐the‐loop experiments conducted on a buck converter prototype.

中文翻译：

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自适应分数阶LQ-PID电压控制器，用于DC-DC降压转换器中的鲁棒干扰补偿

本文提出了一种DC-DC降压转换器的状态相关自调整分数控制策略，以增强其输出电压调节和干扰衰减能力。所提出的控制方案主要采用普遍存在的比例积分微分（PID）控制器，在该控制器中，使用线性二次状态空间调整方法可以最佳地选择增益。然后，最优PID控制器增加了分数阶积分和微分运算符，以改善控制器的自由度以及系统的整体时域性能。由于输入波动和负载阶跃瞬变，分数控制器对有界外来干扰的鲁棒性，通过自适应地将积分微分算子的分数阶调制为受控变量的误差动力学的平滑非线性函数，可以进一步增强该函数。在线动态调整定律由零均值高斯误差函数及其导数组成，用于在每个采样间隔后分别更新两个分数阶。通过测量输出电容器的电流来评估误差导数，以补偿由寄生阻抗注入的噪声。其他控制器参数通过粒子群优化算法进行调整。所提出的自适应控制策略可实现快速转换，最小的瞬态恢复时间以及响应中稳态附近的最小波动。