A novel DSTATCOM with 5-level CHB architecture and selective harmonic mitigation algorithm

• A 5-level cascade H-bridge converter based DSTATCOM for high power application.
• Proposed system is primarily based on an analytic harmonic mitigation method.
• Reactive power is controlled with PI control loop and phase shift modulation.
• Results compared to a PI based controller with a multilevel space vector modulator.
• The proposed system works at the fundamental frequency thus reducing switching losses while presenting good dynamic response.

This paper proposes a five level cascaded converter for Distribution Static Compensator (DSTATCOM) implementing a novel modulation algorithm with harmonic mitigation and a PI controller with phase shift modulation for reactive power control. The modulator operates at fundamental frequency and the whole system satisfies grid code requirements using a simple passive output filter tuned with 11th harmonic. The behavior of the proposed system has been successfully compared with another one with multilevel space vector pulse width modulation. Results show its capability of ensuring satisfactory dynamic response at low frequency operations, resulting improved efficiency and reduced output filter requirements over more conventional systems.