Modulation System for a Series VAR Compensator Based on a Current Source Converter

Abstract

The use of a DSP with peripherals, such as PWM modules, in the control of voltage source converters (VSC) is widely used in our days in FACTS. These peripherals allow some concurrent operation, the control and modulation algorithms can be executed at the same time, they have internal hardware which can be dedicated to producing the most common technique of space vector modulation (SVM) for VSC. Anyway, these simultaneous tasks cannot be executed when a current source converter (CSC) is controlled because the modulation algorithm cannot be implemented in the DSP peripherals. The algorithm must be executed in a sequential mode and most computation resources of the DSP must be devoted to generating the modulation algorithm. As a result, the bandwidth is reduced due to the increasing in the sampling time. This paper presents a field programmable gate array (FPGA) based algorithm for adapting any VSC modulation strategy to control a CSC. Many engineers know the VSC and its modulation strategies, but they do not know so deeply the strategies for controlling the CSC. The main advantage of this proposal is that the wealth of knowledge and experience associated with series VAR compensators based on VSC can be immediately applied to a series VAR compensator based on CSC without requiring further analysis. Experimental results confirm the feasibility of the proposed structure