A Hysteresis Current Controller for Grid-Connected Inverter with Reduced Losses

ABSTRACT:

In this paper, a hysteresis current controller with reduced losses for three-phase grid-connected inverter is proposed. In the proposed hysteresis current controller, one of the inverter phase is clamped to the positive or negative inverter buses depending on the polarity of the phase current. Totally, each inverter phase is clamped for the duration of one third of the fundamental output period. As the inverter phase is inactive when the current is the highest, the switching losses are reduced. Simulation and experimental results are included to show the effectiveness of the proposed controller.

KEYWORDS:

1.      Current controller

2.      Hysteresis

3.      Grid-connected inverter

4.      Losses

5.      Clamped

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig.1. Power controller of grid-connected inverter

 EXPECTED SIMULATION RESULTS:

Fig.2. Output current and switching pattern of: (a) conventional hysteresis

current controller, (b) proposed hysteresis current controller

CONCLUSION:

A simple hysteresis current controller with reduced losses has been proposed in this paper. In the proposed current controller, one of the inverter phase is clamped to the positive or negative DC bus, depending on the polarity, when the magnitude of the current is the greatest. This lead to reduction of the average switching frequency as well as the switching losses. Simulation and experimental results have shown that the proposed hysteresis controller is able to reduce the switching losses without sacrificing the output current waveform.

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