Sinwave Inverter and Square wave Inverter

The answer is in your question sine wave is better but more expensive, square wave is not so good but cheaper.

they are different way of modulation. but they are all belong to pulse wide modulation. One is SPWM, one is PWM. the first use a sine signal modulate a triangle wave, but the later use a dc feedback level modulate a saw wave. the first can easily be changed to a sine waye by a filter. the later can be more suitabel for a stabilizer.

they all ca be used in home and office and factory

The difference between sinusoiidal and sqare wave converters are a more important for the planne duse of it. Becuase of the use of a square wave instead of a sinus wavw, a square wave converter has a higher conversion efficiency and gives you more power output ata giver power in put. These types of vonverter are sometimes much cheaper than sinus converters. But using a square wave in converting leads also to a square wave output and gives a huge amount of higher frequencies (Fourier analysis). Sensitive equipment operating at such a power source may be damaged or is at least not working, because their power input filters are unable to block the strong high frequencies of the square waves.

So before buying one of these converters you should think what equipment you plan to power with. For exampole: powering a hair dryer you can use a square wave converter, powering a computer you should use a sinus converter.

Greetings

He's asking about inverters NOT converters. An inverter converts DC level voltages to an AC line voltage (120 or 240VAC). There are three fundamental types: Sine wave, modified sine wave and square wave. And as stated by another, the use determines which type you buy.

Sine wave inverters tend to be more expensive but have very low harmonic distortion in the AC waveform produced. Therefore, a sine wave invterter is most appropriate for sensitive equipment that relies on a low distortion, low noise power input. In this day of offline power supplies with good filtering, this is less of an issue.

Modified sine wave uses a DAC to produce a stepped sine wave. Since the sine wave has steps in it rather than a smooth continuous waveform, there is some distortion and noise introduced. The step size depends on the resolution of the DAC. To lower the distortion, additional filtering can be added. But this can be very expensive so only very high end inverters use this technique. Inverters for home use do little in the way of lowering the distortion which for most uses (powering radios, tv's, computers etc...) is of no importance at all. You may see a little added noise in a TV picture but consumer inverters are generally good enough that this does not occur.

Square wave inverters use a swqare wave (two states: on or off) to produce and average AC voltage that sits around the required rms value (120VAC or 240VAC). This type of inverter uses a minimum of parts and can be built very cheaply. BUT, the inverter introduces a great deal of distortion since the output is also a square wave. Cheap inverters do nothing to smooth this out. This type of inverter can be used for applications where distortion is not a concern such as powering motors and lights. But in general, electronic systems don't like the high distortion and will either not work properly or the distortion will show up as hum or noise of some sort in the output of the system. Needless to say, the noise will extend out to frequencies in the Mhz so radio systems nearby the inverter may be affected aswell.

In general, mid-priced consumer quality inverters are modified sine wave and can be used for most applications without problems.

J

If you're just running incandescent lights, resistance heaters, and not too
heavily loaded small motors, the cheaper square wave unit is fine.

Computers and sensitive electronics are much happier with sine wave inputs.

Pragmatist wrote:

If you're just running incandescent lights, resistance heaters, and not too heavily loaded small motors, the cheaper square wave unit is fine. Computers and sensitive electronics are much happier with sine wave inputs.

REPLY: While the above answer is partially true, the answer to the question of which is better for home use is quite another matter. If the home is off-grid or relying heavily on alternative power sources such as wind, solar and perhaps genset power which is stored in batteries until needed, the answer may be different.

To begin with computers themselves use a switched mode power supply and really do not care if a MSW or sinewave inverter feeds it. Home electronics on the other hand does care since they are designed for sine wave and do not possess the extra filtering required for hum free operation from MSW. Secondly all the household appliances which rely on timers using a zero crossing clock circuit go crazy on MSW and run fast.

An off-grid powered house will have a number of induction motors and also micro wave ovens. They may also have a bread maker. These devices are not happy running on MSW power. In fact some will no trun at all. Variable speed devices such as fan motor controls or drill motors with SCR controllers do not work well on MSW.

In addition, despite having a lower efficiency rating 89% (sinewave) versus 95% (MSW) the sine wave inverter will yield about 20% more run time on a given battery charge than what the same loads being driven by an MSN inverter does.

While I worked as an applications/ sales engineer for Xantrex I did some testing to compare pure sine versus MSW driving the exact same load. Induction motors run cooler and draw less curent during start up when powered by a sine wave inverter. I provided 1800 watt invertes of both kinds to an air conditioner manufacturer and they in turn gave me complete test results.

The complete answer to the original question is far more involved than you might assume at first glance.

regards to all

http://powerelectronics.com/power_semiconductors/power_mosfets/power_modified_sinewave_inverter/