Nobumasa Matsui, Fujio Kurokawa and Keiichi Shiraishi
The purpose of this paper is to present a new control method for a power turbine generator (PTG) as a waste heat recovery system using an overall shipboard system model that…
Abstract
Purpose
The purpose of this paper is to present a new control method for a power turbine generator (PTG) as a waste heat recovery system using an overall shipboard system model that ascertains startup characteristics.
Design/methodology/approach
The PTG system is a waste heat recovery‐type generation system making use of exhaust gas from the main shipboard diesel engines. With the PTG systems, control during startup is not entirely clear. Startup characteristics from power turbine startup through synchronization to the system bus are ascertained using an overall shipboard system model.
Findings
A startup sequence control is clarified for a combination of gas valve operation and load bank. A prototype constructed on the basis of the simulation. As a result, in the startup process, so as to limit speed overshooting that is 0.83 p.u. at 100 percent output from main diesel engine as the severest condition. The synchronization to the system bus is attained, and highly satisfactory results are achieved.
Originality/value
The PTG is an extremely effective system for fuel cost reduction in the face of rising fuel prices, and systems capable of providing several thousand kilowatts are being considered.
Details
Keywords
Nobumasa Matsui, Fujio Kurokawa and Keiichi Shiraishi
The purpose of this paper is to present an improved model and its applied adaptive controller for a waste heat recovery generation system using a power turbine generator (PTG…
Abstract
Purpose
The purpose of this paper is to present an improved model and its applied adaptive controller for a waste heat recovery generation system using a power turbine generator (PTG) with an accurate model on shipboard that is employed by an identification method on the basis of an overall system model.
Design/methodology/approach
The PTG system has been developed as a waste heat recovery type generation system making use of exhaust gas from the main shipboard diesel engines. Conventionally, control of a plant is exercised using the proportional‐integral‐derivative (PID)‐based controller. The PID controller, however, is difficult to keep in place because of fouling conditions and variations across time. Thus, the load bank controller is proposed using a PID‐based controller. The controller should take into account both the fouling conditions and variations across time because the exhaust gas contains considerable amounts of ash and soot. Hence, an accurate model needs to improve the dynamic characteristics of the PTG system. The identification method clarifies the PTG system. The unknown parameters of the PTG speed model can be estimated using the prediction error method after the mathematical model is transferred to the state‐space model.
Findings
Simulation results are verified with measured data of a prototype. In the transient response of the PTG speed, all the errors are within 0.23 percent. The proposed model using the identification method shows the error between the accurate model and the standard to be less than 10 percent. The proposed controller is evaluated by comparing it with the conventional controller. As a result of using the proposed controller, limit speed overshooting is improved by more than 25 percent. Hence, the proposed model is confirmed to have excellent property.
Originality/value
The PTG is an extremely effective system for fuel cost reduction in the face of rising fuel prices, and systems capable of providing several thousand kilowatts are being considered.