Difference between Synchronous Generator and Induction Generator

Hello, readers welcome to the new post. Today we will discuss the Difference between Synchronous generators and Induction generators. In electrical engineering, especially in electricity generation, there are 2 main sources of energy conversion, first is the motor and the second is the generator. A generator is a device that produces electrical energy and a motor produces mechanical energy. Motors and generators are further divided into AC and DC motors and generators according to their power generation and usage.

A synchronous generator is a type of alternating current generator. A steam turbine or a water turbine synchronous generator is used to generate power in wind turbines. Here we will discuss different points to find the difference between synchronous generators and induction generator

Introduction to Synchronous Generator

• A synchronous generator is a synchronous machine that transforms mechanical power into AC power through a method using electromagnetic induction.
• This generator is also called alternators or AC generators. The word “alternator” used that define what produces AC power.
• It is also called a synchronous generator since it operates with synchronous speed for generating AC power with the required frequency.
• A synchronous generator can come in single-phase or poly-phase

Working Principle of Synchronous Generator

• The working of a synchronous generator is based on Faraday’s law of electromagnetic induction.

emf= dΦ/dt

• It defines the rate of change of flux in any device resulting in EMF in the device. If the device is static and the field is moving it will cause a field in the device.
• For a synchronous generator rotor rotates and produces a field in the stator. To understand the EMF induced in any device, read the article on the voltage induced in a loop

Introduction to Induction Generator

• The induction generator also called the asynchronous generator is an AC electrical generator that works on the principle of induction motors for generating electrical power.
• The regular AC induction motors are used as generators without any changes. Since they can recover energy with easy control,
• They are best for different applications such as mini hydro power plants, wind turbines, or reducing high pressure.
• The induction generators use creative reaction current through external sources.
• This generator comes with an AC rotor and is not bootstrap with the use of residual magnetization for black star de-energized distribution like synchronous machines do
• Power factor correction capacitors are added to neutralize the constant value of variable reactive excitation current.

Difference between Synchronous Generator and Induction Generator

• Some of the similarities and differences between synchronous and induction generators are described here.
  In a synchronous generator, the speed of rotation of the rotor is equal to the speed of rotation of the field on the stator.
  f = (N x P)/120
• But in the case of a synchronous generator, the frequency of the output voltage is controlled by the power system to which it is connected.
• The synchronous generator is not self-excited, it is necessary to connect a special direct current source to it.
• However there is no need for a special external source for the induction generator as the machine is self-starting.
• The presence of carbon brushes and separate DC sources complicates the design of the synchronous generator and increases its cost.
• However, the induction generator is self-starting and does not need carbon brushes and slip ring, so its construction is the simplest and the maintenance cost is also lower.

Working principle of Induction generator

• An induction generator generates electrical power when the speed of rotation of the rotor is greater than the synchronous speed (this is the speed of rotation of the field in the stator).
  If we have a normal 4-pole induction motor that runs at 60 Hz, it will have a synchronous speed of 1800 RPM (revolutions per minute).
  According to this formula, we can find the synchronous speed.
• nsyn = 120fe/P
• In this equation,
  nsyn is the synchronous speed.
• fe is the electrical frequency.
• P is the motor pole number.
• If we have another similar number of pole machines operating at fifty-hertz frequencies, then it will have a speed of 1500 revolutions per minute.

• The motor rotation speed is less than the synchronous speed (nsync).
  The difference between the rotor speed and the synchronous speed is known as slip.
  Suppose the motor rotates at 1450 rpm and has an Nsync (synchronous speed) of 1500 rpm, then its slip is (+3.3) percent.
  In the normal operation of an induction motor, the synchronous speed is greater than the rotor speed.
  It allows the rotor flux to produce a current in the rotor, and this current produces a flux in the stator whose polarity is opposite to the stator flux.
  In this way, the rotor followed the stator flux, with currents in the rotor being induced at the slip frequency.
  In the case of a generator, the prime mover (which supplies mechanical power to the generator) drives the rotor at a speed that is higher than the synchronous speed.
  In the case of a generator, the stator has also induced a current in the rotor and produced a flux because the opposite rotor flux now joins the stator, a current is formed in the stator and the motor now works as a generator as it produces electrical power.

Faqs

• Difference between Synchronous Motor & Synchronous Generator
• Frequency-Power and Voltage-Reactive Power Characteristics of a Synchronous Generator
• Synchronous Generator Capability Curves
• Synchronous Generator Ratings
• Power and Torque in Synchronous Generator

That is all about the Difference between a Synchronous Generator and an Induction Generator all details has explained. IF you have any questions ask them here