Dynamic analysis and control of a solar power plant—II. Control system design and simulation

Abstract Based on the process analysis developed in the first part[1] of the present study and on frequency and time domain methods, the design of the steam generator control system of the EEC solar power plant is dealt with in this paper. More precisely, two different solutions are considered: the one, of quite simple and traditional implementation, using only Proportional Integral Differential (PID) regulators; the other, including more sophisticated control functions, using adaptive dynamic compensators of special form. The comparison of the two control systems, both endowed with feedback and feedforward control actions, clearly shows how the application of the more sophisticated temperature regulation does guarantee much better feedback control capability. This latter property is certainly crucial for water cooled solar receivers due to the very large time delays existing between the main control variable (the feedwater mass flow rate) and the controlled temperatures. On the other hand, feedback control performance requirements are strictly dependent on the achievable accuracy of the measurement of the thermal power entering the receiver, as this measurement is used to get feedforward solar disturbance compensation. In this regard, it is also shown that, with reasonable accuracy of the thermal power measurement, the control system is able to compensate solar disturbances of any amplitude.