(2) Speed, the current double closed-loop speed control system when the steady-state operation, the two regulator input voltage and output voltage deviation is the number? 

A: The speed and current dual closed-loop speed control system when the steady-state operation, the two regulators are the input bias voltage is zero, by the formula n = Un = Un *, n = n; Uim * = Idm, Idm = Idl. 

 (3) In the speed and current dual closed-loop speed control system, the two regulators are PI regulator. When the system is running with rated load, the speed feedback line suddenly disconnected, the system re-enter the steady-state, the current regulator is the input bias voltage to zero? Why? 

  A: When the system is running with rated load, the speed feedback line suddenly disconnected, then Un = 0, = Un *- Un = Un *, so that Ui to reach Uim, 0, rate of increase in n, when the system after re-entering the steady-state , that is, Id = Idl, then, = Uim *- Idl 0, are no longer changes, changes in rotational speed n is no longer, but at this time than the rotational speed n at the time of the feedback line speed to break big. 

 (4) Why is the speed with integral control system is not static poor? 

A: Speed regulator integral system, to achieve non-static error is due to the characteristics of integral control regulator, that is, the accumulation of points and the role of memory. 

 (5) Double-loop speed control system (PI), load changes, Idl> Idm, asked bicyclol speed control system ASR and ACR how-conditioning, the result? 

A: When the load changes, Idl> Idm, speed decreased rapidly, the current Id soon to Idm, and of limited amplitude, rapid rate of ASR saturation, ACR has been limiting conditions, to form a blocking phenomenon, long-running will damage the system.

2. System 

Speed regulator and current regulator in the Double Loop DC Motor Control System can be summarized as follows: 

(1). The role of speed regulator 

Speed regulator is a speed control system of the dominant regulator, which allows speed n will soon change with a given voltage Un * changes in steady-state speed error can be reduced, if the PI regulator can achieve the non-static error. 

 1) The effect of load changes in the role of anti-disturbance. 

  2) The output amplitude of the decision limit the maximum allowable motor current. 

(2) The role of current regulator 

   1) As a regulator of the inner ring, outer ring at the speed of the adjustment process, it makes the current closely followed the given voltage Ui * (that is, the outer ring modulator output) changes. 

     2) Fluctuations in voltage from the role of disturbance rejection in time. 

   3) The speed of the dynamic process of ensuring that the maximum allowable motor current, thereby speeding up the dynamic process. 

   4) When the motor overload or stall when the armature current limit of the maximum, automatic protection from the role of acceleration. Once the fault disappears, the system automatically return to normal. Yesterday, the role of the reliable operation is very important.

Ⅱdouble-loop speed control system common faults analysis 

1.Introduction of a system 

(1). Double-loop speed control system components in Figure 1. Current loop: from the current regulator LT, trigger CF (input transformation for the CSR), silicon-controlled rectifier bridge, motor armature and current loop transform LB component. the speed of outer ring: the speed regulator from ST, current loop, such as link inertia, motor and load moment of inertia and the speed of transformation components SB. in the double-loop speed control system, the speed of the decision loop of the running characteristics of the whole system and stability, and play a leading role, and to change the current ring plays the role of the internal structure of the system is dependent, but since it is as a whole to participate in the closed-loop speed to the speed of a direct impact on the work of the closed-loop, it must first good debugging current loop, and then testing the speed of outer ring, so that the whole system has good dynamic performance.