Patent ID: 11961648
Assignee: BEIJING UNIVERSITY OF TECHNOLOGY
Field: Measurement (Instruments)
Classification: CPC G  H | IPC G  H

Claim 3:
4. The rapid demagnetization method of claim 3, wherein an input of the closed-loop control module of the demagnetizing magnetic field comprises the optimized set value of the demagnetization parameters, an intensity Hoperpv of the demagnetizing magnetic field measured by a flux meter, environmental parameters measured by temperature and humidity sensors, the magnetic medium to be demagnetized, a range of the optimized set value of the demagnetization parameters, a range of the environmental parameters measured by temperature and humidity sensors and the type of the magnetic medium to be demagnetized; an output of the closed-loop control module is the magnetic medium to be demagnetized; an intermediate processing process of the closed-loop control module involves a magnetic field controller sub-module, a charging and discharging device sub-module, a magnetic field generating device sub-module, a magnetic field sensor and environmental sensor sub-module; and the closed-loop control module is operated through the following steps:
in the magnetic field controller sub-module, feeding the optimized set value of the demagnetization parameters, the range of the optimized set value of the demagnetization parameters, the range of the environmental parameters measured by the temperature and humidity sensors, the type of the magnetic medium to be demagnetized and values measured by a magnetic field sensor and an environmental sensor back to a magnetic field controller; and acquiring a demagnetization voltage required by the magnetic field controller via an intelligent PID algorithm for controlling the demagnetizing magnetic field, expressed by equation (10):

Uopercv=fcontrol({Hopersp,αopersp},Hoperpv,{temperature,Humidity, . . . })  (10);

 wherein Uopercv is the demagnetization voltage; Hoperpv is the intensity of the demagnetizing magnetic field measured by the flux meter; {temperature,Humidity, . . . } represents environmental parameters comprising temperature and humidity; and fcontrol(·) represents the intelligent PID algorithm for controlling the demagnetizing magnetic field;
in the charging and discharging device sub-module, transferring the demagnetization voltage Uopercv in a form of a digital signal output by the magnetic field controller to a charging and discharging device to generate an actual demagnetization voltage value U′opercv through a power supply, a high-capacity capacitor, a resistor-capacitor-inductor (RLC) oscillation circuit and a voltage multiplier circuit, expressed by equation (11):, U
       oper
       cv
      
      
       →
       
        
         f
         circuit
        
        (
        ·
        )
       
      
      
       U
       oper
       
        ′
        ⁢
        cv
       
      
     
     ;
    
   
   
    
     (
     11
     )
    
   
  
 

 wherein fcircuit(·) indicates a demagnetization voltage generation circuit in the charging and discharging device; and U′opercv is the actual demagnetization voltage value generated by a demagnetization circuit;
in the magnetic field generating device sub-module, transferring the actual demagnetization voltage value U′opercv generated in the charging and discharging device to a demagnetization coil in the magnetic field generating device to produce a demagnetizing magnetic field with an intensity of HoperProduce; and at the same time, demagnetizing the magnetic medium to be demagnetized in the magnetic field generating device to obtain a demagnetized magnetic medium Z, expressed by equation (12):, U
       oper
       
        ′
        ⁢
        cv
       
      
      
       →
       
        
         f
         coil
        
        (
        ·
        )
       
      
      
       
        H
        oper
        Produce
       
       
        →
        
         
          f
          demag
         
         (
         ·
         )
        
       
       Z
      
     
     ;
    
   
   
    
     (
     16
     )
    
   
  
 

 wherein fcoil(·) is the demagnetization coil in the magnetic field generating device; HoperProduce is the intensity of the generated demagnetizing magnetic field; fdemag(·) represents a physical process of demagnetization; and Z is the demagnetized magnetic medium; and
in the magnetic field sensor and environmental sensor sub-module, acquiring a measured value Hoperpv of the intensity of the demagnetizing magnetic field intensity via the flux meter; acquiring environmental data {temperature,Humidity, . . . } via the temperature and humidity sensors; feeding Hoperpv and {temperature,Humidity, . . . } back to the magnetic field controller; and modifying parameters of the magnetic field controller in a closed loop, and applying modified parameters of the magnetic field controller to demagnetization of a next magnetic medium to be demagnetized to ensure the stability of the demagnetizing field intensity.