This paper proposes a new open-loop synchronization method for three-phase three-wire PWM converters connected to the utility grid. It presents a good performance under unbalanced and highly distorted grid voltages. Moreover, it has a better performance in terms of distortions in the synchronization signals if compared with other open-loop methods and it has a good transient performance due amplitude, frequency and angle disturbances. In addition, a frequency adaptation algorithm is proposed for applications where large frequency variations are expected, such as in weak grids. Experimental results using a DSP TMS320F2812 are given to demonstrate the good performance of the proposed synchronization method.

New Synchronization Method For Three-phase Three-wire Pwm Converters Under Unbalanced And Distorted Grid Voltages

This paper presents a comparative analysis of six digital current control techniques applied to three-phase voltage-fed PWM converters connected to the utility grid. Basic requirements are established and comparison criteria are used to justify the selected current control technique. The comparison contributes for the selection of the best current control technique for a given application. Finally, abacuses, tables and experimental results are shown in order to present the performance of these controllers under unbalances and harmonics in the grid voltages

Comparison of Six Digital Current Control Techniques for Three-Phase Voltage-Fed PWM Converters Connected to the Utility Grid

This paper proposes a new open-loop synchronization method for three-phase three-wire PWM converters connected to the utility grid. It presents a better performance in terms of distortions in the synchronism signals if compared with other open-loop methods. Moreover, it has a good transient performance due to both angle and frequency disturbances, as well as input currents with low total harmonic distortion (THD) when used to synchronize PWM rectifiers, even under unbalanced and highly distorted grid voltages. In addition, a frequency adaptation algorithm is proposed for applications where large frequency variations are expected, such as in weak grids. Experimental results using a DSP TMS320F2812 are given to demonstrate the good performance of the proposed synchronism method

New Synchronization Method for Three-Phase Three-Wire PWM Converters under Unbalance and Harmonics in the Grid Voltages

In this new control algorithm, to take into consideration the transient of the LC filter during the discretization time, a fourth order matrix state equation of the current and the voltage on the d-q frame have been discretized, and precise discrete equations of the inverter has been introduced. Using these equations, a dead beat controller consisting of a d-q current minor loop and a d-q voltage major loop, with precise decoupling of the d-q components has been developed

Digital control of three-phase PWM inverter with LC filter

This paper describes the implementation of a strategy to obtain the currents reference of a shunt filter active using the method of the Theory of Generalized Instantaneous Power applied to the control of a generator Induction of feeding a nonlinear load. The objectives are to establish control of generator excitation and reduce harmonic distortion caused by nonlinear load. It is made a comparison with other method for obtaining the reference currents, the dq synchronous reference. First, they are simulations using the Borland C++. The control and communications necessary for the supervisory stage were implemented via DSP - TMS320F2812.

Implementation of a shunt active filter using the Theory of Generalized Instantaneous Power

This paper develops a systematic design procedure based on discrete decoupling by state feedback applied to three-phase PWM rectifiers. A discrete model for synchronous frame is developed for three-phase PWM rectifier with an L filter. This model takes into account the computational delays presents in the discrete implementation. Deadbeat response is obtaining without the requirement of a current controller in the axis d. Moreover, discrete servo controllers to ensure unit displacement power factor and regulated DC link voltage are developed. Finally, experimental results are presented to demonstrate the feasibility of the proposed procedure, algorithms and the performance of the overall system.

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Marcelo Hey Duarte

Papers

Análise e implementação de retificadores PWM trifásicos com resposta de tempo mínimo utilizando desacoplamento por retroação de estados