Generalized Space Vector Modulation for Current Source Converter in Continuous and Discontinuous Current Modes

Abstract

Three-phase current source converter tends to be attractive in future industrial applications. Therefore, the discontinuous dc-link current will occur if the current source converter operates in case of light load, which will distort the grid current. Many interesting solutions have been reported to deal with these problems. However, most of them are only valid in the discontinuous current mode (DCM) but not suitable in other conditions such as continuous current mode (CCM). With the different load conditions, there are two operational cases for the current source converter according to the different states of dc-link inductor current i <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> . Case 1: the inductor current i <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> is continuous. Case 2: the inductor current L is discontinuous. To solve this problem, a generalized solution is proposed in this article, which is effective for both two cases. First, the operation principle of current source converter is analyzed and the disadvantages when the i <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> is discontinuous are revealed. Second, a new solution is proposed by using the new calculation method of duty cycles, where the current source converter can operate in both two cases. And then, the proposed solution is compared with the traditional one. The total harmonic distortion of grid current in traditional solution is 23.34%. However, it is reduced to 3.90% with the proposed solution. Finally, the proposed solution is carried out on the TMS320F28335 digital signal processor + XC3400 field-programmable gate array digital control hardware platform. The experimental results verify the effectiveness of the proposed solution.