Control of indirect matrix converter with bidirectional output stage for micro-turbine

Abstract

In this study, a new AC-DC-AC matrix converter is developed. This matrix converter is designed to connect a micro-turbine to the grid, to replace the traditional system used in micro-turbines, which is based on an inverter-rectifier system (VSR/VSI) with energy storage elements. A specific power circuit is introduced. The circuit consists of two stages, where the second stage is bidirectional. Also, a new switching technique is presented for the circuit mentioned above, which works with two voltage space vectors. The first vector corresponds to the input voltages (variable frequency) and second one to the output voltages (fixed frequency). This technique switching allowing to replace the VSR/VSI regarding operational concerns, with less loss, at lower cost and lower weight. For verifying the control algorithm, a laboratory prototype has been developed, using among other elements a Spectrum Digital eZdspTM TMS320F2812 card. In addition, the model predictive control (MPC) is used to control the electrical power of the micro-turbine generator by manipulating the fuel flow. The suggested method provided the optimal functioning not only for the small step changes but also for large random step changes.