Georges Salloum

Hybrid excitation synchronous motor control in electric vehicle with copper and iron losses minimization

This paper presents an optimal current control for the hybrid excitation synchronous motor in electric vehicle application. The control aims to meet the torque and speed requirements while insuring minimal copper and iron losses. Extended Lagrange multipliers optimization method (Kuhn-Tucker conditions) is used to elaborate analytical expressions for the optimal reference armature currents as well as for the field current if with respect to armature current and voltage constraints. Simulation over the new European driving cycle proves that the proposed optimal control leads to the lowest losses compared to the results obtained by other synchronous motor control strategies.

Control of a hybrid excitation synchronous generator connected to a diode rectifier supplying a DC bus

This paper deals with the modeling and the control of the hybrid excitation synchronous machine (HESM) connected to a diode bridge rectifier. The set is operating as a DC generator that supplies an isolated grid in embedded applications such as aircraft electrical power generation. Saturation effects have also been taken into account. The aim of the control is to maintain the DC bus voltage constant when the load and/or the speed of the rotor vary. Simulation results validate this approach.

Optimal control of the hybrid excitation synchronous machine for electric propulsion in electric vehicle

This paper presents an optimal current control for the hybrid excitation synchronous motor in electric vehicle application. The whole electric propulsion system is modeled including the battery and converters. The control aims to meet the torque and speed requirements while insuring minimal copper and iron losses as well as inverter and chopper losses. Extended Lagrange multipliers optimization method (Kuhn-Tucker conditions) is used to elaborate analytical expressions for the optimal reference armature and field currents with respect to armature current and voltage constraints. Simulation over the New European Driving Cycle proves that the proposed optimal control leads indeed to the lowest losses.

Effect of iron losses on the model and control of a hybrid excitation synchronous generator

In this paper, a new compact brushless machine, the hybrid excitation synchronous machine (HESM) is presented as a potential candidate to replace the complex structure based on three separated machines, presently used in aircraft electrical power generation system. A particular attention is paid to the iron losses effect on the model and control of the HESM operating as a generator in embedded applications. Contrary to the permanent magnet motor control, where iron losses consideration brings complex regulation approach, this paper proves, analytically and by simulation, that taking into account iron losses while modeling the hybrid excitation generator does not induce major modifications to the model and does not affect the control strategy.

Power operating domain of a cascaded doubly fed induction machine

The paper deals with the steady state operating limits of a cascaded doubly fed induction machine (CDFIM) in terms of active and reactive powers. An analytic method is suggested to derive the power region, in which the machine can operate safely without exceeding its rated parameters. The proposed steady-state analytical study has been thoroughly validated by simulations using an elaborated model of the CDFIM implemented on Matlab-Simulink. It is shown that the power capability is subject to several limitations. For a limited speed range the reactive power consumption and generation are determined by the stators current maximum values. The study is further extended to illustrate the effect of the slip range and the terminal voltage on the power limit curves.

Original article: Hybrid excitation synchronous generator in embedded applications: Modeling and control

The paper deals with the modeling and the control of the hybrid excitation synchronous machine operating as a variable frequency generator that supplies an isolated load in embedded applications such as aircraft electrical power generation. The elaborated model is suitable for simulation and is adapted to the generator mode. In addition, it includes the magnetic circuit saturation effect. The aim of the control is to maintain the output voltage magnitude constant when the load and/or the speed of the rotor vary. Simulation results and experiments validate the approach. The electrical parameters of the laboratory prototype machine are identified prior to the control test.

New voltage sensorless approach for maximum constant power tracking of WECS based on a cascaded DFIG

The paper proposes a new control strategy of a grid connected variable speed wind turbine (WT), based on a cascaded doubly fed induction generator (CDFIG). The generating plant is carried to extract the maximum power relative to the predicted mean wind speed, thus eliminating the power fluctuations associated to high frequencies component. Moreover the system attempts to adjust the power factor of the generated power according to grid code requirements. This can be achieved by means of a bidirectional back to back PWM converter. A virtual flux oriented vector control is applied for the decoupled regulation of active and reactive powers, leading to grid voltage sensorless operation. The suggested method ensures high efficiency and enhances the energy quality by feeding constant power into the grid, regardless wind fluctuations.

Modeling and control of a stand alone cascaded doubly fed induction generator supplying an isolated load

The modeling and control of a variable speed cascaded doubly fed induction generator feeding an isolated grid in aircraft application is presented. Despite the complexity of the generator an efficient controller can be elaborated based on the theory of a unified reference frame vector representation. An indirect decoupled vector control of terminal voltage is implemented using field orientation techniques. The controller insures good tracking of voltage magnitude and frequency regardless load and speed variations.

New approach for maximum power tracking of a variable speed WT at constant power generation, under normal grid conditions

In this paper, we suggest a new control approach for maximum power extraction applied to a variable speed Wind Turbine (WT). The proposed method aims to generate a constant maximum power defined over a given interval. The power set point is derived based on the mean wind speed predicted value. Since the wind speed turbulence component does not contribute to the average produced energy but only affects the power quality, the averaging period is chosen in order to eliminate the power fluctuation generated by this high frequencies component. This technique insures a better energy quality and retains a high system efficiency.

Study, modelling and control of a single-phase power factor corrector based on the Sheppard-Taylor topology

In this paper, a single-phase power factor corrector (PFC) based on the Sheppard-Taylor topology is studied. A novel mathematical representation of the converter is elaborated using the state-space averaging technique. In order to emphasise the usefulness of such model, three pulse-width-modulated (PWM) multi-loops control schemes are proposed and developed in the aim of ensuring a unity power factor at the AC-source side and a regulated voltage at the DC-load side. The first one uses the simple and robust hysteretic-based controller; the second one employs a conventional PI regulator; whereas the third one is based on the model nonlinearity compensation approach. The control systems are tested through simulations under both rated and disturbed operating conditions. The system performance is evaluated in terms of source current total harmonic distortion (THD), input power factor, DC voltage stabilisation, and regulation following load variations.