Research On Control Strategy Of Permanent Magnet Direct Drive Fan For Hydrogen Production Load

Over-exploitation and use of fossil fuels as a result of the energy shortage and environmental pollution problems is the great challenge facing human society today.Not only does wind energy have huge reserves,but it also has the advantage of being clean and pollution-free.It has become the best choice for new energy development in various countries.The wind power generation system connected through the DC bus is output in the form of DC electrical energy,and there is no need to consider the frequency and other issues,and the control structure is simpler compared with the traditional AC power grid.Therefore,the system structure can be used to improve the quality of electricity consumption while reducing the system's operating loss,and it can also solve the problem of wind abandonment by combining the hydrogen production load.The permanent magnet direct drive fan system for hydrogen production load in this paper is composed of permanent magnet direct drive wind power unit,lithium battery energy storage unit and hydrogen load unit.First,after studying the characteristics of the hydrogen production load,it can be known that increasing the input power of the hydrogen production load electrolytic cell can indirectly increase its input current and improve the efficiency of hydrogen production by the load.Then,an improved hill-climbing search method is proposed for the permanent magnet direct-drive wind power unit,which enables the system to achieve accurate control when it is not necessary to accurately measure the wind speed,and achieves the expected effects of fast tracking speed and high steady-state accuracy.At the same time,the motor-side PWM converter of the permanent magnet direct drive wind power unit adopts current speed control,and the grid-side PWM inverter of the permanent magnet direct drive wind power unit uses directional vector control based on the grid voltage.Then,in order to stabilize fluctuations in the power output of the wind,to maintain a stable and uninterrupted supply of electric power to the DC bus voltage,herein also studied the charge and discharge control method for a lithium battery energy storage system.After comparing the advantages and disadvantages of several charging and discharging control methods of lithium batteries,the charging and discharging control methods of constant voltage and current limiting are used to study lithium batteries.Finally,a simulation model of a permanent magnet direct-drive fan system forhydrogen production load during the operation of hydrogen generation from the wind ionization grid is established in Matlab.Considering the capacity of the hydrogen production load and the capacity of the power generation unit,the overall performance index of the wind ionization grid hydrogen production system is set.According to the permanent magnet direct-drive wind power unit and the state of charge and discharge of the lithium battery,the system can be divided into 4 working modes under the operation mode of hydrogen generation from the wind power grid.The simulation results show that each part of the system can meet the system's operating requirements under different working modes,and achieves safe,stable and efficient hydrogen production and stable operation of the system.