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This paper presents a new method to balance the DC link voltages in a 3 level Diode Clamped Rectifier, even in the presence of unbalanced loads which cause a non-zero neutral point current. The method employs an offset which is added to each of the inverter modulation waves. This offset causes a zero sequence voltage which can drive the desired neutral point current whilst maintaining balanced DC...
When a synchronous buck converter is operated with zero voltage switching (ZVS) and fixed frequency, the direction of the current in the output inductor is alternated each switching period. Thus the output current ripple of the converter is high to ensure zero voltage switching operation at maximum load. With interleaved outputs this leads to high circulating currents at low loads. In this paper,...
The locomotive battery requests its testing system special requirements of excellent DC charge/discharge current which is sensitive to the fluctuation of the voltage. It also needs a fast transfer speed between charge and discharge state. Simple converters without appropriate filter can't meet the requirement mentioned above. The decay of the Chebyshev filter increases fast with frequency in the stop-band...
A new discrete-time model for pulse-width modulated (PWM) converters operating in the discontinuous conduction mode (DCM) which leads to the exact discrete-time mathematical representation of the averaged values of the output signal is proposed. This model can also provide the averaged values of other internal signals with little increase in simulation time. The use of piecewise linear (PL) iteration...
Electric and hybrid electric vehicles are possible solutions to reduce the air-pollution and oil dependence of the transportation sector [1,2]. The fuel cell electric vehicle is currently considered to be the car of the future and consequently the automotive industry devotes great research effort and important resources to develop these technologies and to integrate them in their future vehicles....
A solution developed for power quality conditioning (PQC) applied in distributed generation system is presented. The method is exploiting the capabilities of the DC/AC converter of a system that has been developed to generate electric power by utilizing alternative, renewable and waste energies. The power quality conditioning is based on the application of space vector theory, using an algorithm easy...
Recently, skill preservation of an expert and skill training have been a serious problem of the medical or production fields. This paper proposes a task preservation and reproduction of multi-degree-of-freedom motion using interaction mode control based on bilateral motion control. The proposed task preservation system is composed of two modes; acquisition mode and reproduction mode. In the acquisition...
The paper describes a vision based method and implementing procedure allowing for collision-free, on-the-fly grasping of objects travelling on conveyor belts. The ensemble conveyor belt + actuator + sensor is configured as a m ?? 3 -axis Cartesian robot, leading to a problem of cooperation between multiple robot manipulators subject to the multitasking control of a computer. The collision-free grasping...
The development of Hybrid Electric Vehicles is one of the most effective solutions to improve our environment. For the purposes of improving the characteristic and efficiency of Hybrid Electric Vehicles, different hybrid drive train topologies with super capacitor based energy storages have been studied with concern about energy sources control and management. The methods of controlling mean power...
This paper describes a method to identify and assess power loss mechanisms in power MOSFETs for switched circuits. An accurate behavioural MOSFET model is employed in a circuit simulator to analyse the performance of a trench MOSFET technology. A synchronous buck converter for point of load (PoL) applications underlies the study of MOSFETs' switching behaviour. The methodology aims at the derivation...
The paper investigates the effects of EMI filter in the dynamics of a buck converter. It is shown theoretically that the EMI filter may increase significantly the load sensitivity of the voltage-mode-controlled converter but the peak-current-mode-controlled converter is quite insensitive to the EMI filter interactions. Experimental validations are carried out using a buck converter under three different...
The dynamic behavior of the discussed radial active magnetic bearings is analyzed using a finite element-based parametrization coupling model. Numerical calculations of the open-loop controlled and the closed-loop controlled system are performed. The results presented show that the magnetic nonlinearities and cross-coupling effects deteriorate the overall system performances.
Grid-connected photovoltaic (PV) systems usually include a line transformer in their power conversion stage. This transformer guarantees galvanic isolation between the grid and the PV system, thus providing personal protection and avoiding leakage currents between the PV system and the ground. Furthermore, it also ensures that no continuous current is injected into the grid. However, because of its...
The Brushless Doubly-Fed Machine (BDFM) is attractive for use in wind turbines, especially offshore, as it offers high reliability by virtue of the absence of brushgear. Critical issues in the use of the BDFM in this role at a system level include the appropriate mode of operation, the sizing of associated converter and the control of the machine. At a machine level, the design of the machine and...
Multilevel Conversion systems have certain advantages that can be applied in renewable energy systems. To verify that advantages we are developing a re-configurable 1 kW prototype. Among the experiments that we have considered, a sliding mode control law can force this converter to behave like an AC Current Source. We model our converter like a set of Tibuck converters operating sequentially. Some...
As a brake system for small wind turbine, mechanical brake and electric brake by the short circuit of 3-phase permanent magnet generator are used. However, an electric braking method may damage the rotor and/or blades by rapid stop of the generator revolution. Moreover, generator winding may also be damaged by large short-circuit current. In this paper, the electric braking method using NTC thermistors...
This paper proposes modified dual vector current control (DVCC) for the wind turbine application. As in case of conventional DVCC, it fulfills requirements for average unity power factor with suppressed oscillations in active power flow. However, uncontrolled increase in converter output current under unbalanced grid voltage conditions is prevented through imposing limit in its magnitude. Multilevel...
Today the penetration level of wind power on the network is high. The power system stability defined as the ability of the system, for given initial operation condition, to regain a normal state of equilibrium after being subjected to a disturbance is the major problem. In this paper we study the control and we analyse the voltage recovery of a doubly fed induction generator after short circuit faults...
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