Time Domain Performance Indicators of Switching Power Supply Automatic Regulation System

The figure shows a typical step response curve y (u) of a linear time-invariant automatic control system. Its input is a unit step function I (t). If its output final value (i.e., steady-state value) is set to I, and the allowable error band (hereinafter referred to as tolerance band) is set, such as ±2% or ±5%, the system response often shows a damped oscillation process before reaching a steady state. The following performance indicators illustrate the transient response characteristics of an automatic control system. However, the definitions of some indicators here are slightly different from those of the IEC standard.

Figure 1 Typical step response curve y(t) of linear time-invariant automatic regulation system

(1) Delay time td: the time required for the output response to reach 10% of the steady-state value Y = 1 for the first time.

(2) Rise time tr: the time required for the output response to rise from 10% to 90% of the steady-state value.

(3) Peak time tp, the time period required for the output response to reach the first peak.

(4) Maximum overshoot Mp, which indicates the maximum value of the output response exceeding the steady-state value

(5) Recovery time (adjustment time) ts: The time required for the output response to reach the tolerance band and remain within this range.