EE462L, Spring 2014 H-Bridge Inverter (partially pre-fall 2009 version)

1. EE462L, Spring 2014H-Bridge Inverter(partially pre-fall 2009 version)

2. To minimize your time and produce an inverter that works properly, it is very important that you follow the procedure in the lab document LC output filter (100µH, 10µF) Fuseholder s and 10 A fuse s for DC input not shown in this photo 10µF input ripple current capacitor across DC input

3. ! Simultaneously View VGS for A+ and A− (use both scope ground leads) Asymmetrical firing circuit produces slow turn on, fast turn off, to provide blanking A− Off A+ On You must avoid overlap in “on” times

4. Once the H-Bridge is wired, you cannot simultaneously view VDS of A+ and A− (or B+ and B−) on the scope because their source nodes are not the same + + But you can simultaneously view VDS on A+, and −VDS on A−, and then VDS on B+, and −VDS on B−, to check for overlap + A A o ff + on V of A D S – – – – A A o n – V of A D S o ff + + + + B off B + V of B on D S – – – – B B on – V of B D S o ff +

5. ! Loaded (with a resistor) and no output filter Load Voltage – No Filter. ma 1.

6. ! With Filter Load Voltage – With Filter. ma 1. Very Effective!

7. The Filter Has a Cutoff Frequency of About 5kHz + a Vac output 100µH, 9A or 10A − b inductor symbolic + Point “a” in H - bridge Vac output – 10µF, 50V, bipolar, high - frequency capacitor Point “b” in H - bridge

8. + + Vac Vac input output − − Transfer Function L = 100µh C = 10µF R = 12, 8, or 4Ω

9. Your circuit

10. Effect of the carrier frequency

11. Effect of the carrier frequency