High Robustness Control for Robotic Wireless Power Transfer Systems with Multiple Uncertain Parameters Using a Virtual Buck Converter

Abstract

Aiming at achieving high robustness performance in Wireless Power Transfer (WPT) systems for moving robot power supply, this paper proposes a H ∞ robust control method with multiple parameters that vary randomly, including the mutual inductance, load parameter, and operating frequency. These uncertain parameters make the system control extremely difficult. A composite Upper Linear Fractional Transformation (LFT) method is proposed to deal with the system uncertainty, particularly for the mutual inductance detachment, which is very unique and important for WPT systems. A suboptimal H ∞ controller design method is proposed based on Generalized State Space Averaging (GSSA) model in order to simplify the system structure. In controller implementation, a virtual buck converter for phase shifted regulation is proposed to replace real input buck converter. The proposed H ∞ control method is easy to implement because only the output voltage of the WPT system needs to be sampled, and based on which a simple DSP control algorithm is developed. Simulation and experimental results have demonstrated that the proposed control method can achieve less than 15 ms response speed with 70% mutual inductance variation and 50% load variation tolerance respectively.

Dynamic output feedback control for wireless power transfer systems

“…In addition, in WPT system modeling strategy, the generalized state-space averaging (GSSA) modeling method is commonly used because it can transform the nonlinear term in the WPT system into the linear one. By the GSSA modeling method, the control problem in a WPT system with multiple uncertain parameters was researched in [35]. In the reference [36], the robust control was considered in the LCL resonant inductive power transfer system with parameter uncertainty.…”

Enhancing the Robustness of the Wireless Power Transfer System to Uncertain Parameter Variations Using an Interval-Based Uncertain Optimization Method

“…Many works [12][13][14][15][16][17][18][19] have been done to improve the performance of the WPT system with uncertain parameters. In [12], an adaptive frequency-tracking technique is proposed to address coil distance and orientation variations.…”

“…In this way, the WPT system can maintain high efficiency under the variations of coil distance and load current. Aiming at improving the robustness for moving robot wireless power supplies, it proposed in [19] that a H ∞ control method for the WPT system with multiple uncertain parameters. Using this control method, the WPT system can achieve 70% mutual inductance variation and 50% load variation tolerance.…”

“…Although these methods can improve the performance of the WPT system with uncertain parameter variations, there still exist some drawbacks: (1) To deal with uncertain parameter variations, an active compensation system (like frequency tracking system, automatic impedance matching system, and H ∞ control system, etc.) is needed [12][13][14][15][16][17][18][19]. However, introducing the active compensation system will obviously increase the size, control difficulty, and energy losses of the overall WPT system.…”

“…Using the proposed method, the WPT system can achieve good robustness to uncertain parameter variations. Compared with previous methods [12][13][14][15][16][17][18][19], the proposed method only uses passive compensation networks (Q-type impedance matching networks). The structure and control difficulty of the overall WPT system can be reduced.…”