Ledkompensator

Ledkompensator, often called a lead compensator in control theory, is a compensator used to introduce phase lead into a feedback system. Its main purpose is to improve transient response and increase phase margin, helping the closed-loop system respond faster without sacrificing stability.

The standard continuous-time form is a transfer function of the ratio of two first-order terms: C(s) = K (1 + sTz) / (1 + sTp), where K is a gain factor, Tz is the zero time constant, and Tp is the pole time constant. For a lead compensator, the zero is placed closer to the origin than the pole (typically Tz > Tp, or equivalently the zero at -1/Tz is nearer to the imaginary axis than the pole at -1/Tp). This arrangement yields a positive phase contribution over a range of frequencies, increasing the system’s phase margin and often accelerating the response.

Designing a ledkompensator involves selecting the time constants to place the zero and pole so that the phase lead occurs around the system’s crossover frequency, followed by choosing K to meet steady-state or bandwidth requirements. The result is a compensator that can compensate for phase lags introduced by the plant.

Implementation can be analogue, using RC networks or op-amp circuits, or digital, by discretizing the transfer function. Ledkompensators are used in various applications, including servo drives, robotics, and aerospace control systems, where improved stability margins and faster transient behavior are advantageous. They are related to lag compensators and to lead–lag compensators, which combine lead and lag elements.

---