Power Electronics has seen a tremendous growth in recent times and almost all the applications today use power electronic devices in some or the other form. Hence it becomes essential to study the advantages of these devices, which made it so popular. Listed below are some of the advantages and disadvantages of power electronic converters:
Advantages of Power Electronic Converters
Advantages of power electric electronic converters are showing below
- Mass Production : Due to huge development in the production techniques of semiconductor devices, these semiconductor based power electronic devices are now produced in huge bulk and hence have resulted into very low price. These devices are available in a variety of voltage and current ratings to choose from.
- Highly Reliable : Since these devices have no mechanical moving parts, there are very less failure chances and hence has a very rugged performance and long life, provided it is operated under rated conditions.
- Highly Efficient : In most of the applications these devices acts as a switch and we know that in both the modes of the switch, i.e. ON and OFF the power loss in it is very less, and the switching losses are also very low.
- Negligible Maintenance : Again due to absence of mechanical moving parts, the power electronic systems require almost nil maintenance.
- Fast : In comparison to mechanical or electro-mechanical devices the power electronic systems have way faster dynamic response.
- Size : These power electronic systems are very small in size when compared to mechanical systems for similar power ratings and hence less weight, less floor space, less handling issues, less installation cost, less packing and transportation prices and many more.
Disadvantages of Power Electronic Converters
Power electronic systems suffer from some disadvantages also. Following are some of them:
- Harmonics : This is the only serious disadvantages of power electronic systems that it injects considerable harmonics both the sides, to the connected load side and to the power source side. Since the converters alter the sinusoidal waveform according to the requirement, harmonics are generated in the output voltage and current of the converter and also in the input current to the converter. Now these harmonics create a lot of trouble on both the sides.
On the load side if we have motors, harmonics cause problems such as excess heating, more acoustic noise, torsional vibration of motor shaft, commutation issues in DC motors, etc. Hence nowadays we have special VFD motors which are designed to better handle the effects of harmonics. Apart from this we also have filter circuits to limit the harmonics to the load.
On the supply side also harmonics create a lot of trouble. The performance of other equipments connected to the same supply is seriously affected. Harmonics in supply lines also leads to radio interference with communication lines, audio and video equipments. Apart from this the input side transformer also gets overheated and its efficiency gets reduced. Special converter transformers are used when the output has considerable power electronic systems, such as motor drives in industries. Harmonics also increases skin effect in the cables and hence more heating. Thus we need to install filters in the input side also.
- Low Power Factor : Certain power electronic converters operate at very low input power factor and hence it might be required to install reactive power compensation equipments.
- Low Overload Capacity : Power electronic devices work on rated voltage and current provided proper heat evacuation system is provided. Excess current causes hot spots at junctions and burning of devices. High dv/dt leads to false triggering and hence a power electronic device along with it needs compulsory protection arrangements such as snubber circuit etc.
Hence the cost of overall system increases a bit compared to system where normal motors, transformers and no filter circuits are used. However the advantages possessed by power electronic systems are so overwhelming that these disadvantages get over shadowed and are continuously gaining popularity and exponentially increasing in applications.