what could be the best approach to convert DC into AC e.g using sine wave inverter or using an alternator powered by a dc motor and dc voltage for its windings ??
frequency regulation is a problem please specify a method to keep frequency constant e.g 50 Hz
load is 11 kW
Inverter Pros
- Readily available
- Silent
- Few moving parts (cooling fan)
- Excellent frequency control
- Some protections such as overcurrent
Inverter Cons
- Noisy AC and DC bus lines may require an output reactor
- Can be expensive at higher power levels
- Requires enclosure for dust/water protection
Coupled Motor/Generator Pros
- Pure sine wave
- Weather resistant depending upon motor/generator IP ratings
Coupled Motor/Generator Cons
- Many moving parts
- More maintenance
- Louder
- Poor frequency regulation
- Expensive
- Likely custom control circuit
- Large
Really depends on what you are powering
Inverters are more efficient as compared to dc motor and alternator arrangement. This is because inverters use solid-state devices which are more efficient. On the other hand rotating parts of alternator makes them less efficient. However, several arrangements are needed to get pure sine wave.
Adam Nickerson summarised well. The main disadvantage of the inverter is the harmonics produced, but overall it is the best approach for the majority of the applications.
yes harmonics are problems .. how could we get rid of it ? i mean to reduce harmonics ??
To reduce the harmonic content you can apply a more sophisticated inverter (making the waveform look like a roughly sampled sinusoid) and passive filters.
A true sine wave inverter is a good start even though it really isn't a true sine wave. Appropriate output filtering such as a reactor helps considerably.
The First choice is much better on cost and operation.
There are a number of commercial inverters, based on sine PWM.
With the advent in semiconductor technology, DC to AC and AC to DC are converted with Inverters or converters modules, with better series and parallel control for voltage and current control, compared to machines with higher purity(without distortion compare to machines),economy , accuracy and efficiency. Though depending on size and the type of load, with the outdoor or indoor situation the selections could be varied as required, as both are having their own advantage and disadvantages,...
Did you considder a Multi Level Inverter? This will reduce the harmonics as well as the passive componets and for m a fine sinewave.
Let us define our purpose: is it research or real application?
If we consider real application we should analyze commercial
Products; there are a number of them for all power range.
If it is unique application-let us define it srecifically.
Let us define our purpose: is it research or real application?
If we consider real application we should analyze commercial
Products; there are a number of them for all power range.
If it is unique application-let us define it srecifically.
As all of them explained, if the requirement is pure sine wave, then no better option than the alternator driven by DC motor. however, for better frequency and voltage control, inverter is best option.
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