David Gualino

Control strategy for an off-grid hybrid stirling engine/supercapacitor power generation system

In this paper, a novel control strategy is proposed for a hybrid Stirling engine/supercapacitor power generation system functioning in isolated sites rich in sunshine. The controller should drive the system through its electrical part to satisfy the varying load demand and maintain the state of charge of the supercapacitor at an appropriate level. The system includes a thermodynamic machine (Stirling Engine) that drives a Permanent Magnet Synchronous Generator (PMSG). An appropriate power electronics is interfaced between this PMSG and the AC load to be supplied with the desired power. In order to meet the load transient demand, a supercapacitor is used and its delivered power is controlled by mean of a bidirectional DC/DC converter. As the testbed is under construction, a simulation scenarios are proposed to assess the efficiency of the proposed control architecture.

Nonlinear dynamic model identification and MPC control of an Organic Rankine Cycle (ORC) based solar thermal power plant

In this paper a nonlinear dynamic model for a solar thermal Organic Rankine Cycle (ORC) power plant is identified and validated using experimental data gathered on a real 4kWelec ORC based solar thermal power plant prototype. The applied identification structure enables the dynamics of the key quantities (variables to be regulated and constrained variables) to be captured. This leads to a control-oriented model that is used to design a constrained optimal control strategy for the ORC power plant that has to track rapidly some reference electrical power while respecting the system constraints in terms of temperatures and pressures for some key thermodynamic variables. Prior to the control design step, an analysis of the admissible desired steady states is performed to derive feedforward terms that enhance the controller performances. The time responses obtained with the proposed control methodology suggest that a significant reduction in the energy buffer size, consisting in a battery bank associated to the ORC power plant, can be performed.

Experimental Validation of a Novel Control Strategy for an Off-Grid Hybrid Stirling Engine/Supercapacitor Power Generation System

Abstract In this paper a novel optimal control strategy for energy management of an off-grid hybrid Stirling engine/Supercapacitor power plant is presented based on preliminary results proposed in [1]. An implementation of the control strategy is performed on a real time target that drives a dedicated testbed with a DC machine reproducing the behaviour of the thermodynamic Stirling Engine. The DC machine is linked to a Permanent Magnet Synchronous Generator (PMSG) connected to an AC load through an appropriate controlled Power electronics and an energy storage device which is a supercapacitor. The performances of the developed control Strategy are then assessed through experimental results on the testbed.