PMG Alternators in Gas Engines

Working and advantages

                                                                                                                      Permanent magnet alternators coupled with gas engines can give an output power which finds its applications in diverse fields.  But first, let us see how this process takes place and why are PMG alternators better than conventional alternators.

Gas engine--->Permanent magnet --->rectifier--->Inverter--->Power

The above diagram depicts a simple process through which electricity is generated using a permanent magnet alternator and a gas turbine. Depending upon the load requirement, the engine can be operated on a variety of speeds. The PMG Alternator produces a variable frequency AC power which goes to a rectifier before reaching the inverter. The rectifier converts this AC to constant voltage DC. The inverter takes this DC as input and outputs a 50 or 60 Hz high quality waveform. Since the engine can operate at variable speed, high torque is maintained and thus provides full load efficiency.

Hence more output can be drawn from the same engine if it is operated at higher rpm. Also this machine can be used for either 50 Hz or 60 Hz markets without design changes.

The principle advantages of a gas engines coupled with a permanent magnet alternator are standalone capability (i.e., ability to power the facility during a blackout) and non-reliance on the utility for magnetizing current or reactive power.

The most important benefits of using PMG Alternators are:

Fuel Savings: With over 90%efficiency in the alternator, fuel savings automatically increase 15%. Utilizing a variable speed system, matches the power inputs (gas) to the power output (load) in order to maximize the efficiency of the entire system.

Compact: With at least 30% decrease in the size of the alternator, the setup becomes more compact, light weight and occupies less space.

Durable: Fewer components and no bearings mean less wear and tear on the alternators.

Other advantages of using permanent magnet alternator are:

• §  Efficiency up to 91%
• §  Highest power by weight ratio in direct drive
• §  High efficiency at low speed
• §  Simplification of mechanical design
• §  No mechanical adjustment
• §  High quality electrical output
• §  Cost optimization
• §  Fixed and variable speed
• §  No maintenance