Tsinghua University

National Chung Cheng University

Li-Chiun Lin

Chih-Hao Chang

Tsai-Fu Wu

Yu-Kai Chen

Ying-Yi Jhang

Po-Hung Li

A three-phase inverting apparatus and a control method and a paralleled power conversion system thereof are provided. The control method is suitable for controlling a three-phase inverter having a plurality of switch sets, a first inductor, a second inductor, and a third inductor. The control method includes following steps: obtaining a DC bus voltage, a plurality of phase voltages, and a plurality of phase currents; obtaining inductances of the first, the second, and the third inductors; calculating a plurality of switch duty ratios by a division-summation control means according to the DC bus voltage, the phase voltages, current variations of the phase currents, the inductances, and a switching cycle based on a sinusoidal pulse width modulation (SPWM); and generating corresponding control signals based on the switch duty ratios so as to control a switching of the switch sets.

Three-phase inverting apparatus and control method and paralleled power conversion system thereof

The present invention provides a load impedance estimation and repetitive control method capable of allowing inductance variation for an inverter, wherein the method is applied for predicting corresponding next-period switching duty cycles for four switching member sets of the inverter by way of sampling three phase voltages and calculating next-period voltage compensations based on the previous line-period voltage compensations. Moreover, during the calculation and prediction, the method also involves the inductance variations of the output inductors of the inverter into the load impedance estimation matrix equation. Therefore, the three phases four wires inverter with the presented load impedance estimation and repetitive control method can provide a steady output voltage to the loads even if the originally-connected loads are replaced with other different loads. Thus, this load impedance estimation and repetitive control method can indeed improve the drawbacks of the inverter controller based on conventional DQ transformation method.

Load impedance estimation and repetitive control method capable of allowing inductance variation for inverter

A method is for controlling a three-phase current converter. First, subtract a second reference current signal representing the predicted current of the three-phase terminals in the present switching cycle from a first reference current signal representing the predicted current of the three-phase terminals in the next switching cycle to obtain a predicted variation. Then, subtract a feedback current signal representing the feedback current of the three-phase terminals in the previous switching cycle from the second reference current signal delayed by one switching cycle to obtain a current error. Multiply the current error by an error coefficient then add the predicted variation to obtain a current variation. Finally, obtain duty ratios of a plurality of switches, according to the current variation and inductance of the first to the third inductor. The three-phase current converter converts electric power between a DC terminal and the three-phase terminals, according to the duty ratio.

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Hsinchu, Taiwan

Li-Chiun Lin