Research On Aluminum Electrolytic Multi-mode Control Strategy

The process of aluminum electrolysis is an industrial system which is nonlinear, coupling, changeable and with lag effect. The interference among the high-electric field, high-magnetic field and high-thermal field, frequent fault, bad environment make the control more difficult. Meanwhile, single-mode control is hard to make aluminum electrolytic cell to achieve the best working condition. In this paper, according to the complex characteristics of aluminum electrolytic process, aluminum electrolytic multi-mode control strategy was proposed. The approach is that, according to normal aluminum electrolytic, fault and different working condition when the aluminum is acquired, system will adopt different control strategies. Through the control of alumina adding time and adding rate, it can keep alumina concentration within the ideal range, so that the cell can maintain the best working condition. More details as follows:First, under the normal working condition, fuzzy neural network controller is designed under the combination with the characteristics of the fuzzy control and neural network control. To make the alumina concentration within the ideal range, we can change the rate of laying-off to change the alumina concentration in cell by controlling the equipment of laying-off.Second, when there is a failure, all parameters of aluminum electrolytic will change compared with parameters of the normal working condition. But the controller which works under the normal condition can't deal with it. To solve this problem, we use the wavelet neural network predictive controller, which can adopt different control strategies according to the different working state pf the aluminum electrolysis system——the implementation of the multi-mode control strategy of aluminum electrolysis system. The feasibility and superiority of the control is proved by simulation experiment.Finally, hardware interface circuit of aluminum electrolysis including input/output route of switch, input/output route of analog is designed and ensure the good operation of the system. What's more, in combination with the need of practical production and management, network control system is designed, with Visual C++as a platform for the design of management system software. Therefore, from the controller to the hardware circuit and software operation, the integrity of the whole system is guaranteed.