Patent ID: 11890661
Assignee: HEFEI UNIVERSITY OF TECHNOLOGY
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 10:
11. The device of claim 10, wherein each distributed magnetizing and demagnetizing circuit comprises four solid-state relays Ki, where i∈{1, 2, 3, 4}, Ki is in a disconnected state in an initial condition for stamping the sheet material, and the controller is further configured to:
output the pulse signal to a solid-state relay K3 to cause the solid-state relay K3 to be on or off cyclically with a fixed duty cycle, wherein a frequency of the pulse signal is greater than 5 times a frequency of the PWM signal;
adjust a duty cycle of the PWM signal based on the error to cause a solid-state relay K4 to be on or off cyclically with a flexible duty cycle, wherein an absolute value of the error is proportional to the duty cycle of the PWM signal;
output a positive switching quantity signal to a solid-state relay K1 in response to the error being greater than 0, to cause the solid-state relay K1 to be on to magnetize the distributed magnetizing and demagnetizing circuit; and
output the positive switching quantity signal to a solid-state relay K2 in response to the error being less than or equal to 0, to cause the solid-state relay K2 to be on to demagnetize the distributed magnetizing and demagnetizing circuit.