Intelligent regulation and optimization design of frequency converter in energy-saving hydraulic system

Aiming at the problem of high energy consumption of traditional hydraulic system, this paper puts forward an intelligent regulation and optimization design method of frequency converter based on multi-objective optimization, aiming at realizing the synergistic improvement of energy saving and dynamic performance. Firstly, the state space model of hydraulic system driven by variable displacement pump with variable frequency motor is constructed, which covers the state variables such as motor speed, pump outlet pressure and accumulator pressure. On this basis, a variable frequency speed regulation algorithm based on model predictive control (MPC) is designed, and the frequency of inverter and motor shaft current are optimized by multi-objective cost function to minimize energy consumption and pressure tracking error. At the same time, an adaptive fuzzy PID controller is developed, and the PID parameters are adjusted in real time by fuzzy reasoning to enhance the anti-interference ability of the system. In addition, NSGA-II algorithm is used for multi-objective collaborative optimization of system key parameters to form Pareto frontier of energy saving and dynamic performance, and a collaborative control strategy of inverter and accumulator is proposed to further reduce energy consumption through "peak clipping and valley filling" of accumulator. The experimental results show that compared with the traditional PID control, the energy saving rate of this method reaches 38.7%, the pressure tracking overshoot is reduced to 4.5%, and the adjustment time is shortened to 0.6s, which significantly improves the energy efficiency and dynamic performance of the system, and verifies the effectiveness and engineering practicability of the proposed strategy