Paul van den Bosch

Assessment of non-centralised model predictive control techniques for electrical power networks

Model predictive control (MPC) is one of the few advanced control methodologies that have proven to be very successful in real-life applications. An attractive feature of MPC is its capability of explicitly taking state and input constraints into account. Recently, there has been an increasing interest in the usage of MPC schemes to control electrical power networks. The major obstacle for implementation lies in the large scale of these systems, which is prohibitive for a centralised approach. In this article, we therefore assess and compare the suitability of several non-centralised predictive control schemes for power balancing, to provide valuable insights that can contribute to the successful implementation of non-centralised MPC in the real-life electrical power system.

A predictive control solution for driveline oscillations damping

This paper deals with the problem of damping driveline oscillations, which is crucial to improving driveability and passenger comfort. Recently, this problem has received an increased interest due to the introduction in several production vehicles of the dual-clutch powershift automatic transmission with dry clutches. This type of transmission improves fuel economy, but it results in a challenging control problem, due to driveline oscillations. These oscillations, also called shuffles, occur during gear-shift, while traversing backlash or when tip-in and tip-out maneuvers are performed. The first contribution of this paper is the derivation of an accurate piecewise affine drivetrain model with three inertias. The second contribution is concerned with the design of a horizon-1 predictive controller based on flexible Lyapunov functions. Several simulations based on realistic scenarios show that the proposed control scheme can handle both the performance and physical constraints, and the strict limitations on the computational complexity.

Analysis of the market-based service provision for operating reserves in the Netherlands

The electricity sector liberalisation in Europe has contributed significantly towards the creation of competitive markets. The wholesale trading of electricity consists of a market-based segment often complemented by markets for ancillary services, including the provision of operating reserves. In this paper, the authors examine and classify operating reserves that are currently traded in the Netherlands. The principles, under which the provision of these reserves is verified by the Dutch Transmission System Operator (TSO), are illustrated, and inefficiencies of the current verification approach are identified. The verification process of the TSO takes into account specific conditions, but the criteria for assessing the quality of the service provision are not explicitly defined. Furthermore, only a limited number of cases can be assessed due to the non-automated nature of the process. Finally, a proposal is made for the development of an automated analysis tool for assessing the service provision of market parties. This proposal emphasises the need for more robust verification processes in line with the increasing integration of electricity markets in Europe.

Day-ahead economic scheduling of energy storage

This article addresses the day-ahead economic optimisation of energy storage systems within the setting of electricity spot markets. The case study is about a lithium-ion battery system integrated in a low voltage distribution grid with residential customers and photovoltaic generation in the Netherlands, whereas the optimisation objective is to maximise revenues from energy arbitrage in the day-ahead auction. Assuming accurate predictions of the photovoltaic generation, the residential load and the market clearing prices, the constrained optimisation problem is formulated as the minimisation of a cost function, and is solved by utilising an internal model of the battery system to plan the future response of the charging and discharging process. Emphasis is given on the effect of the system efficiency, which significantly impacts the economic performance due to energy losses during the charging and discharging cycles.

Piezo printhead control : jetting any drop at any time

Full flexible use of inkjet printhead units in printing systems requires consistent generation of drops with any given volume and velocity at any moment and place desired. True drop-on-demand is currently hampered by physical phenomena in the printhead. These are residual vibrations and crosstalk resulting from conventional jets. This chapter presents control strategies to overcome these problems. First, with experiment-based control the drop characteristics are measured and the jet pulse that activates the jetting of a drop is optimised. Choosing a proper jet pulse structure, one can deal with single-channel residual vibration, multi-channel crosstalk, and even generalise optimisation over each bitmap to be printed. Secondly, with a model-based control approach, optimised jet pulses can be derived without additional measurement equipment. Considering the inkjet mechanism as an uncertain system and designing a robust pulse allows to deal with differences between model and real system. Both the experiment- and model-based method result in strongly improved drop characteristics, which is experimentally verified and thereby provide very valuable steps towards adaptive printing systems.

High-Precision Force Control of Short-Stroke Reluctance Actuators with an Air Gap Observer

A short-stroke reluctance actuator linearization scheme that simultaneously achieves high linearity, high bandwidth, and low stiffness is demonstrated. These properties are required in high speed and high precision motion systems. They are achieved by combining various control schemes, namely flux feedforward and analog sensing coil feedback for high bandwidth, Hall probe feedback to stabilize the drift, and an air gap observer together with gain scheduling to reduce the remaining stiffness. Using the presented scheme, the attractive force of the actuator can be controlled with high precision without the need for a position or force sensor. Experiments indicate that a linearization error of 50 mN for second-order 200 N force reference profiles is obtained. This translates into force predictability of 99.98%. Furthermore, absolute actuator stiffness below 500 N/m at force levels of 100 N is achieved, which is comparable to more linear Lorentz actuators.

Some study on the identification of multi-model LPV models with two scheduling variables

Conference Name:Universite Libre de Bruxelles. Conference Address: Bruxelles, Belgium. Time:July 11, 2012 - July 13, 2012.

Reasoning with Uncertainty about System Behaviour: Making Printing Systems Adaptive

Any conclusion about a system’s hidden behaviour based on the observation of findings emanating from this behaviour is inherently uncertain. If one wishes to take action only when these conclusions give rise to effects within guaranteed bounds of uncertainty, this uncertainty needs to be represented explicitly. Bayesian networks offer a probabilistic, model-based method for representing and reasoning with this uncertainty. This chapter seeks answers to the question in what way Bayesian networks can be best developed in an industrial setting. Two different approaches to developing Bayesian networks for industrial applications have therefore been investigated: (1) the approach where Bayesian networks are built from scratch; (2) the approach where existing linear dynamic system theory equations are used as a starting point. A comparison with the traditional method of system identification is also included. The main lesson learned from this research is that Bayesian networks provide a very suitable method for reasoning with uncertainty in engineering problems when detailed engineering knowledge is lacking. When detailed knowledge is available, however, Bayesian networks can still be chosen as an alternative to standard engineering methods. They will offer the advantage that the uncertainty about a problem and its solutions becomes explicit. It will depend on the problem at hand whether their performance will be superior to that of standard engineering methods.