Motor greatest hope in the current restricted conditions, to allow full use of motor Guozainengli, preferably in over the course of always maintain the current (torque) to allow the maximum so that the electric drive system as far as possible, starting with the greatest acceleration Dynamic, stable at speed, allowing current down immediately, and immediately load torque equilibrium, which turn into steady-state operation. Based on the engineering design of the DC converter system design. The design of the DC double-loop speed control system to simulate the results of the study show that: a single closed-loop system can not be arbitrary in the current and torque control of the dynamic process. Current super-speed to reconcile overshoot to achieve the desired dynamic performance indicators, has a good dynamic performance. In order to achieve the conditions to allow the fastest start, the key is to be maintained for a period of the current most worthy of constant current process, in accordance with the feedback control laws, current negative feedback can be similar to the constant process. The problem is to start the process of only current negative feedback, and can not be allowed and speed at the same time added to a negative feedback regulator of the input, and arrive at steady speed, as long as the speed and hope that the negative feedback, not * play the main current negative feedback And therefore we use double-speed closed-loop system. This will achieve both speed and current existence of two negative feedback effect and it also enabled their role in different stages