A control method for an improved H-bridge and NPC hybrid cascaded static var generator

Adopting a Hybrid Cascade Static Synchronous Compensator (HC-SVG), which integrates Neutral-Point Clamped (NPC) three-level power units and Cascade H-bridge (CHB) power units, can reduce the number of CHB power units, making it a current research hotspot in the field of reactive power compensation. However, the introduction of high-voltage NPC power units causes high-order harmonics in the DC bus capacitors on both the NPC and CHB sides, affecting the overall compensation performance of the device. This paper proposes an improved control method that extracts and filters the high-order harmonic content of the DC-side capacitors in the reactive power compensation device, resulting in more stable system operation. Finally, a simulation platform is constructed to verify the effectiveness of the theoretical analysis.