PWM is about modulation of a square wave (achieved by comparing a triangular wave with a pure sine wave using a comparator). If modulated just right i.e. if the modulation index is optimal, using the leakage reactance of the output transformer, the HF square wave is easily filtered off leaving a pure sine output!(99% pure sine with a conversion efficiency of about 95% at optimal load) Simple concept isn't it? Actually not:) To add to this complexity is the fact that the input to the modulator needs to be in synch with the mains! This should explain the cost of $2K upward.
I see the mention of brushless motor here. Spoils the game you see.... moving electricals are notorious for their pathetically low efficiency. How low? Well a bad bad 30%!! So compared to a PWM system you may end up using 4 times the number of solar cells to get the same power.
The problem of generation needs to be broken up as follows:
1. The conversion to AC should be sinusoidal. Simple square wave inverters will not work.
2. To have a sinusoidal output, PWM needs to be used
3. The PWM control circuit needs to be mains synched
PWM - Pulse width modulation - a way to generate non square wave outputs from efficient switching circuits.
This is not the only problem. I know that the solar cells that can generate even 5% of the total electrical power that we cosume on an average are pretty darn expensive. Vossman have you got it at scrap rates? Well even if you have not everyone can.
Additionally there will be a costs related to batteries, mounting, wiring etc.
So what's the point? Unless the government heavily subsidizes it.
Slashdot Mirror
PWM is about modulation of a square wave (achieved by comparing a triangular wave with a pure sine wave using a comparator). If modulated just right i.e. if the modulation index is optimal, using the leakage reactance of the output transformer, the HF square wave is easily filtered off leaving a pure sine output!(99% pure sine with a conversion efficiency of about 95% at optimal load) Simple concept isn't it? Actually not :) To add to this complexity is the fact that the input to the modulator needs to be in synch with the mains! This should explain the cost of $2K upward.
I see the mention of brushless motor here. Spoils the game you see.... moving electricals are notorious for their pathetically low efficiency. How low? Well a bad bad 30%!! So compared to a PWM system you may end up using 4 times the number of solar cells to get the same power.
The problem of generation needs to be broken up as follows: 1. The conversion to AC should be sinusoidal. Simple square wave inverters will not work. 2. To have a sinusoidal output, PWM needs to be used 3. The PWM control circuit needs to be mains synched PWM - Pulse width modulation - a way to generate non square wave outputs from efficient switching circuits. This is not the only problem. I know that the solar cells that can generate even 5% of the total electrical power that we cosume on an average are pretty darn expensive. Vossman have you got it at scrap rates? Well even if you have not everyone can. Additionally there will be a costs related to batteries, mounting, wiring etc. So what's the point? Unless the government heavily subsidizes it.