PID feedback circuit schematic diagram

The current output by the PID control system obtains the required compensation current magnetic potential I2eWe through the operational amplification and driving links. The operational amplification link is a proportional control in the automatic control system. The biggest disadvantage of proportional control is the existence of residuals. When there are higher requirements for control quality, it is necessary to add integral control that can eliminate residuals on the basis of proportional control. Even if the deviation in the differential control system is very small, as long as a change trend occurs, control can be carried out immediately, which has the characteristics of advanced control. Therefore, this article uses a PID controller in the differential current compensation loop. The PID feedback circuit is shown in the figure. It can control quickly, eliminate residual errors, and has good control performance.
The working process of the PID operation circuit is as follows: when the input signal Ii has a step change, initially CD and C1 are equivalent to a short circuit, and the input signal suddenly jumps to the maximum value of the differential effect. Then as the CD is charged, the negative feedback voltage gradually increases, and the output current I0 gradually attenuates. At the same time, CI is also charged. As the voltage across CI gradually increases, the negative feedback effect gradually decreases, and the output current I0 slowly increases again.