Power electronics Chapter 7 Soft-Switching Techniques
PPoowweerr EElleeccttrroonniiccss Chapter 7 Soft-Switching Techniques
PEREE Pursuing of higher switching frequency Better waveform PWM waveform will be closer to expected waveform Harmonics is easier to be filtered Benefits Smaller volume and weight 4. 44fN0=4.44fNAB 2√LC Faster response 2
Power Electron cs i 2 Pursuing of higher switching frequency Pursuing of higher switching frequency Better waveform • PWM waveform will be closer to expected waveform • Harmonics is easier to be filtered Faster response Smaller volume and weight • 4.4 4fNφ =4.44fNAB • LC f 2 π 1 = Benefits
PEREE Disadvantages of higher switching frequency Disadvantages 4 Higher power losses on power semiconductor devices Power loss=f x Energy loss at each switching More severe electromagnetic interference(EMD) Steeper edges introduce more noises Easier to be radiated Solution 4 Soft-switching techniques 3
Power Electron cs i 3 Disadvantages of higher switching frequency Disadvantages of higher switching frequency Disadvantages Disadvantages Higher power losses on power semiconductor devices Higher power losses on power semiconductor devices – Power loss= Power loss=f x Energy loss a f x Energy loss a t each switching each switching More severe electromagnetic interference (EMI) More severe electromagnetic interference (EMI) – Steeper edges introduce more noises Steeper edges introduce more noises – Easier to be radiated er to be radiated Solution Solution Soft -switching techniques switching techniques
PEREE Outline 7. 1 Basic concepts on soft-switching 7. 2 Classification of soft-switching techniques 7. 3 Typical soft-switching circuits and techniques
Power Electron cs i 4 Outline Outline 7.1 Basic concepts on soft Basic concepts on soft-switching switching 7.2 Classification of soft 7.2 Classification of soft-switching techniques switching techniques 7.3 Typical soft 7.3 Typical soft-switching circuits and techniques switching circuits and techniques
PEREE 7.1 Basic concepts on soft-switching Hard-switching u a)Turning-on b)Turning-off The process of power semiconductor device hard-switching 5
Power E l ect r o n cs i 5 7.1 Basic concepts on soft Basic concepts on soft-switching switching Hard-switching switching t u i u i t u i u i t p t p O O O O a) Turning-on b) Turning-off The process of power semiconductor device The process of power semiconductor device hard-switching switching