Will a converter-inverter arrangement work. Since 12VDC - 120VAC is available in the market, and a DC-DC converter must also be available, why not use them in series.
Prasad www.geocities.com/aquariangenius ----- Original Message ----- From: "Lee Hart" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, August 17, 2002 12:07 AM Subject: Re: 120 VDC Inverter > Jim Coate wrote: > > So with my 176 volt pack I just need to add a FET to turn it on/off > > at 60 Hz to make a crude square wave inverter? > > Rod Hower replied: > > You'll need at least 2 FETs, or you could use 4... your standard > > H-bridge... Or you can replace Fet's 3 and 4 with capacitors > > and pulse Fet 1 and 2 complimentary (make sure you have some dead > > time in between turning one on and the other off. If you use IGBT's > > make sure you have anti-parallel diodes on every device. > > The simplest inverter is probably just an H-bridge (4 semiconductor > switches). It intrinsically delivers a square wave. You'll want some > inductance in series with the load (which can be the motor itself if you > only use it for driving motors). You'll also need some capacitance to > filter the sharp edges and voltage spikes. The larger the L and C values > you can stand, the closer the output can approach a sinewave. > > If you use only 2 switches with 2 series capacitors for the other two > legs, the capacitors have to be HUGE at 60 Hz and high power levels. > But, it has the advantage of being intrinsically current-limited. The > capacitors also guarantee no DC offset. > > If the DC input voltage happens to be different that the peak AC output > voltage, you'll need an autotransformer (or transformer if isolation is > also needed). At 60 Hz, a transformer will be big and heavy. The size of > an autotransformer is proportional to the voltage difference it needs to > provide; if you only need to boost the AC output voltage 10%, the > autotransformer is 10% of the weight of a transformer. > -- > Lee A. Hart Ring the bells that still can ring > 814 8th Ave. N. Forget your perfect offering > Sartell, MN 56377 USA There is a crack in everything > leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen >
