Design and control of small DC-link capacitor-based three-level inverter with neutral-point voltage balancing

Keyword: Carrier-based pulse-width modulation (CB-PWM)Electrolytic capacitor less inverter Grid current quality Neutral-point clamped inverter

Mesh Keyword: Carrier-based pulse-width modulation (CB-PWM)Electrolytic capacitor-less Grid current Input current qualities Neutral point clamped inverters Neutral-point voltage balancing Neutral-point voltages Three level neutral point clamped (NPC) inverter

All Science Classification Codes (ASJC): Renewable Energy, Sustainability and the Environment Energy Engineering and Power Technology Energy (miscellaneous)Control and Optimization Electrical and Electronic Engineering

Abstract: This paper presents a method to improve the quality of input-output currents in a three-level neutral-point clamped (NPC) inverter with small direct current-link (DC-link) capacitor systems. The inverter systems with the small DC-link capacitors have several advantages in terms of cost, volume, life-time, and reliability when compared to inverters that use large DC-link capacitors. However, there are problems with respect to the deterioration of the input current quality and a severe ripple of neutral-point voltage (NPV), which can cause an aggravated output current. To mitigate these issues, an additional circuit is applied for the input current shaping and a compensation algorithm is applied to reduce the ripple voltage of NPV. The effectiveness of the proposed design and control method is verified with various simulation and experimental results.

Funding: This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20171210201100).

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