단상 NPC 3레벨 인버터의 효율 개선과 고조파 저감을 위한 새로운 불연속 전압 변조 방식
Novel Discontinuous PWM Method for Improvement of Efficiency and Harmonic Reduction with a Single Phase Neutral-Point Clamped Three-level Inverter
- 주제(키워드) Clamp switching method , DPWM method , Unipolar PWM method , Three-level NPC inverter
- 발행기관 아주대학교
- 지도교수 이교범
- 발행년도 2017
- 학위수여년월 2017. 2
- 학위명 석사
- 학과 및 전공 일반대학원 전자공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000024841
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
This paper proposes a discontinuous pulse width modulation (DPWM) method to improve current total harmonic distortion (THD) and achieve high efficiency for a single-phase neutral-point clamped (NPC) three-level inverter. In the most of the single phase systems, the bipolar or unipolar PWM (UPPWM) method is commonly used. However, these PWM methods have the disadvantages in an aspect of the power losses because of many switching operations. The DPWM methods can improve efficiency but increase current THD as well. To reduce these weaknesses, the proposed DPWM method combines two PWM methods, which are the UPPWM and conventional DPWM. Since the proposed DPWM method has all the advantages of both methods, the optimal performance about the power losses and current THD can be obtained. The process to divide optimally operation range of two PWM methods is introduced based on the analysis of the power loss and current THD. The effectiveness of the proposed DPWM method is shown through the simulation and experiments.
more목차
CHAPTER I. INTRODUCTION 1
CHAPTER II. SINGLE PHASE NPC THREE-LEVEL INVERTER 4
2.1 Operation Description of NPC Three-level Inverter 4
2.2 Output Voltage of Single Phase Three-level Inverter 7
CHAPTER III. POWER LOSSES IN POWER SWITCH 9
3.1 Conduction Losses 9
3.2 Switching Losses 10
3.3 Total Power Losses in Power Switch 11
CHAPTER IV. SWITCHING STRATEGIES FOR SINGLE PHASE THREE-LEVEL INVERTER 12
4.1 Unipolar PWM method (UPPWM) 12
4.2 Conventional DPWM method in single phase inverter 13
4.3 One pole clamped PWM (OPC-PWM) 14
CHAPTER V. PROPOSED DPWM METHOD 17
5.1 Principle of the proposed DPWM method 17
5.2 Decision of the optimal point 21
CHAPTER VI. SIMULATIONS 24
CHAPTER VII. EXPERIMENTAL RESULTS 28
CHAPTER VIII. CONCLUSIONS 33
REFERENCES 34
