Ioan Serban

Electronic Load Controller for Stand-Alone Generating Units with Renewable Energy Sources

This paper deals with the analysis of an electronic load controller - also known as dump load - in order to improve the regulating behaviour in stand-alone generating systems. The considered dump load can be implemented in two alternatives. Each solution is analysed from the current harmonics injection point of view, through simulations and experimental trials

A novel transistor-less power decoupling solution for single-phase inverters

This paper introduces a novel active method for power decoupling in single-phase PWM inverters, which has the main advantage of not requiring additional switching components, besides the inverter H-bridge. The proposed transistor-less power decoupling solution requires two AC capacitors placed on each inverter leg, while an original control method ensure both the primary function of the inverter and the transfer of the double frequency pulsating power towards the decoupling capacitors. By this solution, the required DC capacitor is substantially reduced and so increasing the inverter lifetime, whereas requiring no additional semiconductors makes it more reliable and less expensive than other solutions. The performed analysis based on simulation results show that the proposed inverter performs as claimed.

Automotive Electrical Actuation Technologies

The present paper presents an overview of actual high performance electric drives for automotive applications. The field of applications spans a broad range from active steering, power steering, electromechanical brakes, clutch and shift actuators, suspension, damping and stabilization actuators, heating, ventilation, and air conditioning up to starter-generators and traction, including x-by-wire (e.g. steer-by-wire, brake-by-wire). Most of these applications require high performance motors with a high torque/volume (mass) ratio, low inertia, high dynamics, good field-weakening and high temperature standing capability. In the actual situation on the global automotive market the demands for the electric actuators become more stringent

Single-phase operation of an autonomous three-phase induction generator using a VSI-DL control system

This paper presents an efficient method to supply single-phase loads with a three-phase induction generator (IG). A combination between a properly controlled voltage source inverter (VSI) and dump load (DL) ensures, besides the phase balancing of the IG, the voltage and frequency regulation. The VSI operates at constant frequency - thus keeping the system frequency also constant - and deals with unbalances compensation, while the DL performs the voltage regulation. Simulations are carried out in order to highlight the reliability of such a configuration.

New State Observers and Sensorless Control of Wound Rotor Induction Generator (WRIG) at Power Grid with Experimental Characterization

The paper deals with a wound rotor induction generator (WRIG), also known as the doubly-fed induction generator. A complete experimental set-up is presented and analyzed. It is composed of: WRIG, two power electronics converters connected in the rotor side of WRIG, a line filter, and the data acquisition and control system (dSpace DS 1103). Both converters are commercial units and are vector controlled using appropriate interfaces. They are back-to-back connected, sharing the same DC bus, one supplied through a line filter from the power grid, and the other one with the output on the rotor of the generator. The stator of the generator is directly connected to the power grid. Two stator flux observer topologies were investigated and compared, one with the voltage model in parallel with the current model and the other one with both models connected in series. A speed estimation strategy, which works also during the synchronization procedure, was implemented and tested. It is based on model reference adaptive system (MRAS) principles. All control strategies, the flux observers and the MRAS, were developed in Matlab-Simulinkreg and implemented using a dSpacereg DS1103 single-board control and acquisition interface. Different tests were performed, and sample results are presented and discussed in the paper. The schemes used are illustrated in the paper, and the experimental results are shown and analyzed

Frequency control and unbalances compensation in stand-alone fixed-speed wind turbine systems

This paper deals with the control of a small power wind turbine working in stand-alone mode. The fixed-speed fixed-pitch wind turbine drives a permanent magnet synchronous generator (PMSG), which supplies three-phase and single phase loads. Due to the presence of such consumers, unbalanced voltages appear. In addition, as the loads supplied by this generating unit are variable by nature, frequency regulation must be achieved.

A voltage-independent active load for frequency control in microgrids with renewable energy sources

This paper presents a voltage-independent control method for an active load (AL), which is designed for integration in microgrids with the main purpose of frequency control. Ideally, the AL should behave like a controllable linear current sink whose active power is independent of the input voltage. The proposed AL approaches the aforementioned conditions by combining a robust hardware structure with an optimized control method for this kind of applications.

Comprehensive Experimental Analysis of the IPMSM for Automotive Applications

The present paper deals with the in-depth experimental analysis of PMSM considering the motor design solution for an electric assisted active steering system as a case study. The experimental motor and the complete laboratory set-up including the power electronic, motor control and measurement devices are presented. A comprehensive measurement procedure will be described and the measurements results will be presented and interpreted.

Controlling variable load stand-alone hydrogenerators

The paper aims to establish a common way in controlling the electric energy quality in micro hydro plants. The considered situation deals with the stand alone synchronous and induction generators. The research investigates a power control scheme that would allow avoiding the mechanical control of the turbine. For the control study, simulations were made for variable loads. The considered control circuit performs the voltage and frequency regulation, separately and together, for both types of generators.

A PHIL system designed for testing the dynamic response of microgrid units

A cost-effective power-hardware-in-the-loop (PHIL) system designed for dynamic tests in microgrids (MGs) is discussed in the current paper. For this purpose, the PHIL system is based on a four-quadrant power converter, which emulates the MG behavior using a reduced-order model. A photovoltaic (PV) inverter is added as testing unit, while the dynamic event is created by connecting a resistive load and an induction motor near the PV inverter point of connection with the emulated MG. The proposed system is investigated through experimental tests accomplished using a laboratory-scale system.