Neutral point potential balance algorithm for three-level NPC inverter based on SHEPWM

• Published in: Electronics letters Vol. 53; no. 23; pp. 1542 - 1544
• Main Authors: Zhang, Xiao-hua, Yue, Wen-kai
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 09.11.2017
• Subjects: balance control algorithm; harmonics suppression; hysteresis; hysteresis controller; load current; modulation index; neutral point potential balance algorithm; neutral point potential feedback; neutral‐point‐clamped three‐level inverter; nonlinear control systems; Power electronics, energy conversion and sustainability; PWM invertors; redundant vector adjustment; selective harmonic elimination pulse‐width modulation; switch sequences; three‐level NPC inverter; three‐phase pulse‐width modulation signal; three‐phase SHEPWM waveform; voltage vector action angle; redundant vector adjustment; load current; switch sequences; three-phase SHEPWM waveform; three-level NPC inverter; selective harmonic elimination pulse-width modulation; balance control algorithm; hysteresis; three-phase pulse-width modulation signal; PWM invertors; neutral point potential balance algorithm; neutral-point-clamped three-level inverter; modulation index; nonlinear control systems; voltage vector action angle; hysteresis controller; neutral point potential feedback; harmonics suppression
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2017.3191

In order to obtain the capability of neutral point potential balancing with low switching frequency, a novel balance control algorithm for neutral-point-clamped (NPC) three-level inverter based on Selective harmonic elimination pulse-width modulation (SHEPWM) are proposed. On the basis of the switch sequences and voltage vector action angle corresponding to the three-phase SHEPWM waveform at different modulation index, the three kinds of redundant vector adjustment schemes are designed. Then, load current and neutral point potential feedback to the controller, and the three-phase pulse-width modulation signal adjusted directly by the hysteresis controller to realise neutral point potential balance. Experimental results show that different redundant vector adjustment schemes have different neutral point potential balancing speed and average switching frequency, but do not affect the harmonic elimination ability of the line voltage.