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ABSTRACT: Two techniques are presented to balance the filter capacitor voltages of a multipulse rectifier with the active injection operating on a variable-frequency supply. The active injector consists of a low-rated bidirectional switch that modifies the behavior of a 12-pulse rectifier at either low or high frequency, resulting in 24-pulse or multilevel pulse width modulation operation, respectively. The operation of the rectifier and the injector, the practical issues that unbalance the capacitor voltages, and the methods to correct this imbalance are explained together with experimental results obtained with a 4-kW prototype.
IEEE Transactions on Industry Applications 03/2011; · 1.66 Impact Factor
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ABSTRACT: The derivation of an optimal ripple injection technique for multi-pulse rectifiers operating on variable frequency aerospace supplies is presented. This is determined by analysing the multi-level PWM operating mode of a 12-pulse rectifier that uses a bidirectional switch to modify its behaviour. The resultant line currents are almost sinusoidal, the THD being 1.06%. The injector current is 2.5% of the load current. The principle of the multi-level PWM injection mode, idealised waveforms and the determination of the ideal ripple injection are explained and experimental results obtained with a 4 kW prototype are presented.
Power Electronics Congress, 2008. CIEP 2008. 11th IEEE International; 09/2008
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ABSTRACT: A three-phase, multilevel rectifier using active voltage injection with one MOSFET device is presented. The injector consists of a bidirectional switch that modifies the behavior of a 12-pulse rectifier resulting in either 24-pulse or multilevel pulsewidth-modulated (PWM) operation. The resultant input currents are almost sinusoidal, the line current THD being 2.36% for 24-pulse operation and 1.06% for PWM operation. The MOSFET current is 2.9% of the load current. The circuit operation, idealized waveforms and modulation strategy are explained and experimental results are presented.
IEEE Transactions on Power Electronics 06/2008; · 4.65 Impact Factor
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ABSTRACT: This paper presents a 3-phase, voltage-sourced, 36-pulse converter that draws almost sinusoidal currents. The converter results from the combination of a series connected, 12-pulse, voltage-sourced rectifier with a passive voltage injection circuit and a bi-directional switch. The voltage injection circuit uses a single-phase rectifier bridge and a single-phase transformer. Both the voltage injection circuit and the bi-directional switch operate at six times the supply frequency and have a low rating. In this paper, the converter operation is explained and analysed. Subsequently, the converter is evaluated experimentally using a 4 kW, 400 Hz prototype, where the THD<sub>I</sub> of the line currents was measured to be below 1.2%.
Power Electronics and Drive Systems, 2007. PEDS '07. 7th International Conference on; 12/2007
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ABSTRACT: A control strategy is described to drive an active injector for multi-pulse rectifiers operating on variable frequency aerospace supplies. The injection technique utilises a single low-rated active device that carries approximately 2.9% of the load current, and this may be driven with either low-frequency pulses or high-frequency, pulse-width modulation to produce 24-pulse operation or multi-level PWM operation respectively. The resultant input currents are almost sinusoidal, the line current THD being 2.36% for the 24-pulse operation and 1.06% for the PWM operation. The control principle, design and performance are presented in this paper. Experimental results of the controller with a 4 kW prototype are shown.
Power Electronics and Drive Systems, 2007. PEDS '07. 7th International Conference on; 12/2007
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ABSTRACT: Multi-motor arrangements have grown as an important field in the manufacturing process where high-performance applications that are able to achieve precise control of position, speed, acceleration, and deceleration are required. Several approaches exist for such synchronisation control all of them with the main aim to synchronize multiple machine axes and to emulate the actions of the mechanism they replace. However, so far little work has been done in the relative speed and position error between axes during the start-up, shutdown conditions and under load impacts on any motor. This paper present a novel multi-motor synchronisation strategy called relative coupled strategy, which can be easily applied into a real industrial environment. This novel approach is specifically compared with the electronic (virtual) line shaft. Results are presented showing the ability of the novel and current strategies to cope with different load conditions.
Electric Machines and Drives Conference, 2003. IEMDC'03. IEEE International; 07/2003
