Control Scheme Based on Improved Odd-Harmonic Repetitive Control for Third-Harmonic Injection Two-Stage Matrix Converter

The third-harmonic injection two-stage matrix converter (3TSMC) not only inherits the advantages of the conventional two-stage matrix converter (TSMC), but also has a simple modulation strategy and low switching losses. The injection current control is the key to achieving sinusoidal input currents of 3TSMC. The injection current reference consists of the third harmonic and its odd harmonics, making it difficult to obtain high control accuracy with a proportional integral (PI) controller. In this article, a control scheme is proposed for the injection current of 3TSMC, which consists of an improved odd-harmonic repetitive controller (IORC), a PI controller, and a feedforward controller. Compared with the conventional repetitive controller (CRC) and existing ORCs, the IORC has the highest gains and bandwidths at odd-harmonic frequencies, offering the proposed control scheme high control accuracy and fast transient response. The stability conditions of the system with the proposed control scheme are analyzed, and the design guidelines for the control parameters are provided on this basis. The experimental results demonstrate the effectiveness of the proposed control scheme.