On-Line Capacitance Estimation of DC-Link Capacitor by Input Current Injection for PWM Converters
نویسندگان
چکیده
Abstract : In this paper, a novel on-line capacitance estimation of dc link capacitor using input current injection is proposed for the ac/dc PWM converters. At no load, a controlled input current at a lower frequency than the line frequency is injected into the input side, which causes the dc voltage ripples at the output side. With the ac voltage and current ripple components on the dc side extracted by the digital filters, the capacitance can be calculated simply through a voltage-current relationship. This method can be implemented only by software without any additional hardware. It is shown that the estimation error is less than 1.5% from the experimental result.
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