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This paper presents an ac-dc-ac reversible nine-phase machine drive system. The grid side converter is composed of Y-connected single-phase bridges. As the machine is composed of three three-phase groups, a three-leg converters are connected separately to each group. The topology does not make use of input isolation transformers and reduces the power processed by converter switches when compared to...
A novel multi-level AC six-phase motor drive is developed in this paper. The scheme is based on three conventional 2-level three-phase voltage source inverters (VSIs) supplying the open-end windings of a dual three-phase motor (six-phase induction machine). The proposed inverter is capable of supply the machine with multi-level voltage waveforms. The developed system is compared with the conventional...
This paper presents two six-phase open-end machine conversion systems. They are composed of three three-leg converters connected in series to a six-phase machine with open terminals, in an open-end winding connection. The converters use diodes to replace controlled switches, making the conversion system non-reversible and with a reduced number of controlled components. In this case, the machine must...
This work presents a comparison between two adaptive filters applied to harmonic and reactive power detection in power electronics conditioners. The objective is to demonstrate their ability of tracking the signal variations without the use of synchronization techniques, with fast dynamic response and low computational burden. The algorithms are simulated and implemented in DSP TMS320F2812 for power...
Optimal Pulse Patterns (OPPs) permit setting the switching frequency of power converters to a low value without compromising on Total Harmonic Distortion (THD). This paper presents the algorithm of calculating OPPs for Medium Voltage converters. The calculation procedure is explained in detail. Results are discussed and an efficient method is proposed to speed up and simplify calculations.
The paper presents a comprehensive approach to the compensation of phase current distortion of grid-connected power inverters. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, voltage fluctuations in the dc link, time delays in the estimation of grid voltages, and the distortion of inverter output voltages due...
In this paper, three unidirectional single-phase rectifiers are proposed. Each converter is composed of two non-controlled legs and two controlled legs. Modelling and control strategy of the system, including a synchronization method, are proposed. In the synchronization method, the grid current is synchronized with the generated voltage ensuring a sinusoidal grid current without zero-crossover distortions...
This paper analyses the position error compensation in quadrature analog magnetic encoders through the iterative linear search optimization algorithm of "steepest descent". In current literature, the sine/cosine signals from the encoder are compensated considering only the gain mismatch, the DC offset components and the non-orthogonality. Nevertheless, the magnetic field distortion due to...
A drive train system (DTS) powered by an ideal voltage source and driving a permanent magnet synchronous motor (PMSM) is discussed in this paper. A two-level, three-phase conventional inverter with no harmonic filters on both AC and DC sides is used as means of power conditioning. This DTS is modelled as a double oscillator according to a simplified drive train in an electric vehicle. Commonly used...
Repetitive schemes are composed by the interconnection of delay lines. These schemes are usually implemented in a digital way, where delay lines are replaced by discrete delays. Each discrete delay is obtained as the ratio between the required delay time in continuous time and the sampling period. A problem arises whenever the delay time of the controller is not an integer multiple of the sampling...
This paper presents a discrete phase-locked loop (PLL) method aimed to provide an estimation of the angular frequency, and both the positive and negative sequences of the fundamental component of an unbalanced and distorted three-phase reference signal. The design of the proposed scheme is based on a discrete model of the generator of a three-phase signal. This model involves both positive and negative...
This paper is focused on the analysis and design of a switching control strategy to correct power factor, to regulate output voltage of a single-phase active three-level rectifier (SPATR) and to guarantee low harmonic distortion using a type of hysteresis current-mode control. The switching criterion is designed analyzing the stability of the switched linear system, to avoid information loss from...
This paper presents the modeling and control design of a single-phase full bridge neutral point clamped (FB-NPC) multilevel converter used in an active power filter (APF) application. The proposed topology is aimed to compensate reactive power and current harmonic distortion. Based on the system model, a multi-loop controller is proposed, which is aimed to accomplish three control objectives, namely,...
This paper investigates a power shunt filter composed by four standard h-bridge converters, acting in four-wire system. Compared with the usual four-wire shunt filters, the proposed converter permits reducing the dc-link voltages, the harmonic distortion or the switching frequency. Suitable control strategies to adjust the filter currents as well as the three dc-link voltages are presented. The PWM...
This paper presents a phase-locked loop (PLL) method aimed to provide an estimation of the phase angle and the amplitude of the fundamental positive sequence component of a three-phase reference signal subject to severe unbalance and high harmonic distortion. In addition the proposed scheme provides the estimation of the angular frequency, and both the positive and negative sequences of the fundamental...
This paper presents a current controller for a transformerless single-phase two-level inverter grid connected by means of an LCL output filter and subject to a sever harmonic distortion in the grid voltage signal. The controller indirectly controls the grid-side current by controlling the inverter-side current. The inverter-side current controller is simpler to implement, moreover, it is shown that...
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