Proportional control

About: Proportional control is a research topic. Over the lifetime, 3756 publications have been published within this topic receiving 49050 citations.

Tuning of Proportional Retarded Controllers: Theory and Experiments

Abstract: This brief provides simple tuning rules for the proportional retarded (PR) control of second order systems requiring strong closed-loop damping. A frequency domain analysis allows determining the σ-stabilizability regions of the controller. The analysis provides explicit formulae for tuning the three parameters of the PR controller, namely, the proportional gain, the retarded gain, and the delay. The performance of the PR closed-loop control is experimentally compared with that of a proportional derivative (PD) controller. The experiments show that the PR controller outperforms the PD controller fed using velocity estimates obtained from a high-pass filter in terms of noise amplification, control effort, and position error, and has a similar performance compared with a PD controller supplied with velocity estimates produced by an observer. Numerical implementation of the PR controller is computationally less demanding than the corresponding implementation of PD algorithms using velocity estimation based on filters or observers, since it does not need solving ordinary differential equations and only requires performing two products and a few memory registers for implementing the time delay.

Pattern recognition adaptive controller and method used in HVAC control

Abstract: A pattern recognition adaptive controller configured to dynamically adjust proportional gain and integral time control parameters to minimize integrated absolute errors between a setpoint temperature and a monitored temperature in an HVAC system. The pattern recognition adaptive controller receives a sampled signal representative of the temperature and determines a smoothed signal based on the sampled signal. The controller characterizes a disturbance in the smoothed signal by a damping factor and a closed loop response time. When a significant load disturbance or setpoint temperature change occurs, the controller estimates an optimal gain based on the damping factor, and an optimal integral time based on the response time. The estimated optimal gain and estimated optimal integral time are used to determining a new gain and a new integral time values, to which the control parameters of the controller are then set.

Robust Deadbeat Control Scheme for a Hybrid APF With Resetting Filter and ADALINE-Based Harmonic Estimation Algorithm

Abstract: A novel hybrid active power filter (HAPF) topology is proposed, which shows advantages of the conventional HAPF and the LCL filter in terms of reduced dc-link voltage, lower switching ripples, and less electromagnetic interference injection. To enhance the noise rejection capability of the digital controller, the resetting filters (RFs) are utilized as prefilters before the analog/digital sampling stage. A robust deadbeat current control law is derived based on the average current tracking scheme, where the effect of the RFs is favorably incorporated. To alleviate the difficulties in current controller design, the ac-side capacitor voltage of the HAPF is estimated by using the adaptive linear neural network identifier in the load current feedforward loop. Hence, a simple proportional controller is utilized in the inner current loop. Moreover, the grid current feedback and load current feedforward strategies are used to achieve precise current tracking and fast dynamic response. A 75-kVA prototype system is built for verification. The validity of the proposed HAPF and its control algorithms are confirmed by the experimental results.

Tracking Control of Motor Drives Using Feedforward Friction Observer

Abstract: In motor drives, just as in other mechanical actuators, the friction compensation is extremely important as friction can have adverse impact on the overall control performance. In this paper, a feedforward friction observer (FFFO) is proposed as formulating an explicit analytical expression for the applied observation function. This ensures the cancelation of friction disturbances and time variances at steady state. The proposed observation scheme utilizes the two-state dynamic friction model with elastoplasticity (abbreviated as 2SEP), which is compact in parameterization and captures both the presliding and sliding phases of kinetic friction. The method to identify a motor drive plant with nonlinear friction in the frequency domain has been applied using only few frequency-response-function measurements. The feedback control design is performed with respect to the time delay detectable in the system, thus under additional constraints when determining the control gains. The optimal proportional-integral (PI) control designed this way is compared with the proportional control combined with the observer (P-FFFO). The simulation results show that P-FFFO control compensates faster for frictional disturbances at suddenly changing frictional conditions than PI control. In addition, an extensive experimental evaluation of velocity tracking control discloses P-FFFO as superior in terms of a faster steady-state convergence after various transient phases.