Optimization for Biogas Power Plants using Automatic Control of Gas Pressures
In many cases, gas storages on biogas power plants are not used optimally to store gas as much as their capacity. The digester is sometimes overload to store gas and the controller cannot deliver gas to other storage. Consequently, gas is often released from digester to avoid over pressure. At the end, biogas power plant has less efficiency. Hence, a mechanism to control gas pressure to make different pressure between its storages is required. Fans were used to manipulate the most majority system pressures on a biogas power plant using frequency converters. Measurements, simulations, and experiments were conducted to create a new system on a biogas power plant. A controller, Programmable Logic Controller was used to control the entire system pressure using Proportional-Integral-Derivative algorithm. When the gas pressures are not in the allowable range of pressure, then the controller changes the fans’ frequency to the desired conditions. As a result, gas moves to another storage and system pressures are in the allowable range.
Simulation study on pressure control using nonlinear input/output linearization method and classical PID approach
This paper deals with the comparison of linear PID and a nonlinear control strategy to control pressure in a constant volume using a 4/3 way control valve. For the PID control at least three parameters have to be tuned. Rule sets for PID pressure control are very powerful if they derive directly from parameters which can be found in data sheets of the hydraulic components. Nonlinear control techniques are more complex. Their advantage, however, is that they take the nonlinearities of the plant into account and compensate them. The applied nonlinear approach in this paper is the input/output linearization in combination with full state feedback and state observer. The pole placement problem is approached by analyzing a set of PID control rules which is widely accepted in industry and choosing the pole placement for the nonlinear controller accordingly. In addition, this paper presents another set of PID tuning rules which are derived using ITAE performance criterion. The closed loop poles of these two PID designs have been used to calculate the feedback controller gains of the nonlinear controller. The performance of these two linear PID and nonlinear controller designs is evaluated and compared in simulation based on overshoot, settling time, robustness and complexity.
A Transient Hydrostatic Dynamometer for Single Cylinder Engine Research With Real Time Multi-Cylinder Dynamic Simulation
A new high-bandwidth transient hydrostatic dynamometer test system has been developed that accurately replicates multi-cylinder engine operation using a single-cylinder research engine. Single-cylinder engines are typically used for research because of their low cost and good cylinder accessibility for instrumentation and optics. This dynamometer maintains these advantages while dramatically improving transient and low speed testing capabilities. The system also incorporates hardware-in-the-loop models for simulation of other components that would typically be present in a vehicle application. These models include: adjoining cylinders and ancillary components in the engine, the transmission, driveline, and vehicle load. Utilizing these models it is possible to replicate actual driving cycles. This high-bandwidth transient dynamometer extends the test capabilities of single-cylinder research far beyond the traditional steady state regime, enabling transient speed single-cylinder engine research while providing single-cylinder engine operation that is comparable to the multi-cylinder engine.Copyright © 2003 by ASME