Expertise


The GRÉPCI’s research and development activities are concentrated on six specific areas:


Digital control and simulation of electric drives

This section covers the application of modern control principles to torque and speed control, or to the control of electric drive positions. Electric motors and electronic converters, which are the main components of an electric drive, are multivariable and nonlinear systems whose parameters vary over time. Such systems pose significant challenges in terms of controls. Only modern control techniques, such as nonlinear control, adaptive control and robust control produce outstanding performance (rapid dynamics, robustness, precision, etc.). Mainly, the electric drives analyzed are those equipped with permanent magnet synchronous motors, asynchronous motors and variable reluctance motors.

Particular attention is paid to encoderless closed-loop speed control, based on different types of observers. Our team also develops a library of electric drive models for the The MathWorks Inc.’s Simulink and SimPowerSystems environments.

Professors in charge: Louis-A. Dessaint, Ph.D., Ouassima Akhrif, Ph.D.



Advanced aeronautic systems and robotic controls

This section covers the dynamic modelling and control of aircraft and robots. In the first case, active flight control, which was only recently introduced to civil aviation, and which is made possible by “Fly-By-Wire” technology, is developed for longitudinal and lateral aircraft models. Significant interest is also directed at controller gains optimization and stacking. Fault control is also analyzed, with particular attention paid to fault identification, fault tolerant control and control reconfiguration. Nonlinear control of helicopters is also examined.

In the case of mechatronic systems, manipulator robots and mobile robots are used, with particular emphasis placed on nonlinear and adaptive controls. This research field highlights parameter estimation methods, stability analysis, hybrid control (position/force) of a robot, cooperation between robots, and real-time implementation. We also examine exoskeleton robots, particularly the rehabilitation component.

Professors in charge: Ouassima Akhrif, Ph.D. and Maarouf Saad, Ph.D.



Coordinated voltage control of power transmission network

Demand for electric grids is on the rise, with such networks often operating under less-than ideal conditions, which makes them unstable and subject to breakdowns. Alternators and compensators are the only sources allowing regulated voltage transmission points on networks, not only locally and regionally, but also globally, in order to handle load and topological variations.  In this field, we are developing know-how with a view of developing global control techniques for controlling the network voltage map by acting automatically on the production of reactive power in some groups in the zone in order to improve voltage safety on electricity transmission networks.

Professors in charge: Maarouf Saad, Ph.D. and Pierre Jean Lagacé, Ph.D.



Simulation of electric power networks

Over the last twenty years, simulation has grown to become one of the major tools used in planning and managing electricity transmission networks. Electricity network simulation is a research area ripe with new scientific and technological developments.

For over fifteen years now, the GRÉPCI has been a major Hydro-Québec research partner in the area of network electromagnetic phenomena simulation. The GRÉPCI collaborated with Université Laval and the Hydro-Québec Research Institute in developing SimPowerSystems (SPS). Specifically, Professors Al-Haddad, Dessaint and Champagne developed and built the Power Electronics, Converters, Electric Machines and SPS regulators libraries. Professor Dessaint and his graduate students also contributed to the development of Hydro-Québec’s Hypersim electric grid simulator , a fully digital real-time simulator. The research undertaken in this section notably includes the development and validation of new SPS models. Professor Lagacé participated in the development of models in EMTP-RV.

Professors in charge: Louis-A. Dessaint, Ph.D., Pierre Jean Lagacé, Ph.D.



Power electronics and electric machines

The Group’s activities in this area are focused primarily on static electric energy converters using power semiconductors. The focus is primarily on research on new structures using the soft switch principle, with a view to improving the performance and supply weight-power ratio in embedded applications and in the telecommunications field. The research also covers the development of new harmonized mitigation techniques (active filters, shunts, series and hybrid) for improving electric power quality, and cleaning the harmonics pollution network generated by nonlinear loads (variable speed drives, power supply sources, etc.). Furthermore, research is done to integrate FACTS into the electric grid in order to better control the flow of power, load sharing and, improve transient stability and the damping of the voltage and reactive power regulation system. Furthermore, the new semiconductor components (IGBT, MCT, etc.) are currently being studied for integration into new industrial applications. Finally, modelling and simulation are widely used to facilitate the design of complex converters and the identification of their control laws for various industrial applications.

Professors in charge: Kamal Al-Haddad, D.G.E. and Ambrish Chandra, Ph.D.



Renewable energy

Climate change concerns largely associated with energy generation and consumption have driven researchers to investigate viable and sustainable technologies to meet the ever growing need for electricity to sustain an acceptable quality of life for vast populations inhabiting the planet, with the bulk of them still deprived of this luxury. “Green Power” is the path to developing such technologies using renewable energy sources such as the wind and the sun.

The problem is unique for remote and dispersed communities, for which off-grid solutions are appropriate, using locally available sources. Many communities are interested in pursuing energy efficiency and renewable energy projects as a means of reducing energy costs, developing local economies and increasing local sovereignty over their energy supply, while simultaneously reducing the environmental impact on their traditional lands.

Apart from off-grid applications, grid-connected renewable energy sources constitute another big challenge. Connecting hundreds and thousands of renewable energy sources to the utility network introduces different dynamics to the system, and if the distributed sources are not properly controlled, the grid can become unstable and even fail. As the electric power system moves toward a smart grid in the future, renewable energy technologies will have to adapt to be more compatible with the grid, and vice versa. One important aspect of the smart grid is that it must seamlessly integrate many types of generation and storage systems into a simplified interconnection process. This means that renewable energy systems will need to change from their current role as passive participant on the grid to a state in which they try to improve the quality of power on the grid and actively participate in its operation.

Research work is being done under the supervision of Professor Ambrish Chandra in all areas associated with renewable energies, including various kinds of wind conversion systems (DFIG, PMSG, SCIG), photovoltaic, hybrid systems, including diesel generators, battery storage, grid interfaced, off-grid, PHEVs, V2G, smart grids, etc. DFIG and sensorless PMSG-based wind turbines have already been implemented in the hardware laboratory, and various control techniques have been tested.

Professor in charge: Ambrish Chandra, Ph.D.