DC link ripple analysis on five phase pwm voltage source inverter with unbalance load
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The document discusses the analysis of a five-phase PWM voltage source inverter operating under unbalanced load conditions, focusing on improving reliability and fault tolerance. It emphasizes the importance of selecting proper capacitor sizes to manage voltage ripple and harmonic currents while detailing research methodologies and literature on existing inverter ripple analysis. The ultimate goal is to minimize input current and voltage ripple to enhance inverter performance in fault scenarios.
DC link ripple analysis on five phase pwm voltage source inverter with unbalance load
- 1. DC Link Ripple Analysis On Five Phase PWM Voltage Source Inverter With Unbalance Load Presented by: Haryo Agung Wibowo (15862703) Email: disiniharyo@yahoo.com
- 2. STUDY MOTIVATION • Improve five phase inverter reliability to be able withstand working under any extreme operating condition, such as during faulted load condition
- 3. WHY WE SHOULD DO THIS? • Five phase basically give better fault tolerant level. Motor still be able to run without loosing so much power, even motor are extremely faulted.
- 4. ELECTRICAL PERSPECTIVE • But from electrical point of view, motor fault will rapidly elevate voltage ripple and introduce harmonic current at inverter input terminal. + - +
- 5. ELECTRICAL PERSPECTIVE • But from electrical point of view, motor fault will rapidly elevate voltage ripple and introduce harmonic current at inverter input terminal. Additional Harmonics Capacitor Voltage Threshold (normally+10-12% rated Vdc) Additional loss= In x Rc2 High Voltage Stress High Thermal Stress
- 6. ULTIMATE RESEARCH GOAL • Selecting proper capacitor size which perform well under unbalance load • To do this, we should concern at 3 main parameter: 1. DC current ripple RMS value 2.DC voltage peak to peak value 3.DC current ripple harmonics spectrum All must be analyzed under unbalance circuit operation
- 8. STARTING POINT OF ANALYSIS (I) Easier to perform because can be resolved using algebraic manipulation. However, DC current harmonics spectrum can not be analyzed
- 9. STARTING POINT OF ANALYSIS (II) 1. To achieve spectral decomposition, Current and voltage function must be represented by Fourier series. 2. The calculation will be exhaustive unless mathematical analysis program is utilized.
- 10. END
- 11. Research Background • Electrical fault (short/open circuit) is likely to occur in the motor side 3 phase sources 3 phase rectifier AC/DC 5 phase inverter DC/AC 5 phase motor
- 12. 5 Phase Inverter – Unbalance Load 1 1 1 2 2 2 3 3 3 4 1 4 5 1 5 sin 2sin 5 4sin 5 6sin 5 8sin 5 i I t i I t i I t i I t i I t 1 2 3 4 5 1 2 3 4 5 Unbalance I I I I I i1 i2 i3 i4 i5 In turn, it forces inverter circuit working in unbalance condition (carrying unequal current in every output phase). 5 phase inverter DC/AC
- 13. 5 Phase Inverter – Unbalance Load It causes current and voltage at capacitor terminal increase to a higher level which the magnitude is a function of i1, i2, i3, i4, i5. 5 phase inverter DC/AC If the capacitor specs does not account this influence, when the fault comes, component is about to produce excessive thermal stress, reduce its life time, or might be eventually burnt out
- 14. Research Objective Therefore, it is important to analyze as well as minimize input current and voltage of the inverter (blue sign) under various circuit unbalance scenario, so optimal selection of capacitor design can be made. id vd This is my research area To design capacitor size anticipating worst fault condition
- 15. Research Progress • Literature review from past 25 year transaction • Develop research methodology: Focus how to quantify parameter that is affecting capacitor performance: Input Current Ripple Root Mean Square (RMS) Maximum Capacitor Bus Voltage Ripple See probability that ripple can be reduced by harmonics injection to reference signal
- 16. 5 Phase Inverter – Unbalance Load • Literature Review Though many paper has been published in recent 25 years, however investigating inverter input current or voltage ripple under unbalance load is getting less attention. In addition, only few works are available concentrating on multiphase inverter Therefore synthesizing information to develop research methodology embark from ideal three phase circuit
- 17. 5 Phase Inverter – Unbalance Load • Literature Review Theory developed by Cross et. al (time domain approach) and McGrath et. al (frequency domain approach) show that input ripple current can be evaluated using Fourier series. Downside: 1. To solve Fourier equation precisely, infinite number of harmonic order must be introduced. The calculation will be exhaustive unless mathematical analysis program is utilized. 2. This method would not be able identifying which optimal switching strategy to attenuate input current or voltage ripple magnitude
- 18. 5 Phase Inverter – Unbalance Load • Literature Review Theory developed by Dahono et. al dictated the input ripple current can be evaluated by avoiding Fourier infinite series. The ripple equation is presented in a simple math form. Downside: The calculation, built upon assumption that the circuit is in a perfectly balance set, whereas in practical viewpoint this is not always the case.
- 19. 5 Phase Inverter – Unbalance Load • Literature Review Approach proposed by Pei et. al in 2014, suggest that input ripple current under unbalance circuit condition can be analyzed through a simple math expression. Downside: 1. Ripple minimization technique is not discussed 2. The calculation only developed in three phase circuit
- 20. Literature Review SummaryDesired Criteria Unbalance circuit Avoid Fourier Series Ripple suppression technique Five phase circuit Cross et. al V X X X McGrath et. al V X X X Dahono et. al X V V V Pie et. al V V X X Research Objective V V V V
- 21. THANK YOU
- 22. CONTENT • Quick overview on Five Phase Motor Drive Train • What is my research tell about? • Objective of my research • Literature on Five Phase Inverter • Research Plan: Research Question How do I will contribute
Editor's Notes
- #9: Overdesign capacitor size can be used as an alternative to solve the problem, but it has consequences to system volume, weight, and volume
- #10: But, not by overdesigning, cause we will never know how large the correct system dimension should be.
- #13: This technique, can be developed to derive optimum modulation signal that produce smallest current/ voltage ripple
- #14: 3. This method would not be able to identify which the most optimal switching strategy to attenuate DC ripple current or voltage