Freewheeling Diode

Is Freewheeling diodes used in every inductive circuit?

To protect the components and to prevent voltage spikes freewheeling diodes are used. It is not necessary to use the Freewheeling diodes in every inductive circuit, the circuit may use other components.

What are the Conditions that Freewheeling diodes will fail?

Due to the over voltage, extreme current and voltage rating may cause the freewheeling diode to fail. There should be careful consideration when selecting the diode and installing it.

Freewheeling diode is only used in DC circuits?

To protect the circuit from voltage spikes, freewheeling diode is used in both Alternating current (AC) and Direct Current (DC) circuits with the inductive load.



Freewheeling Diode

In an Electrical circuit, a Diode is a semiconductor device that acts like a one-way switch (it allows current to flow in one direction and restricts the current to flow in another direction). Semiconductor is made up of p-type and n-type materials. Semiconductors have conductivity between conductors and insulators. To control the Load voltage, a switching element is used to switch at a particular frequency.

A severe high voltage occurs at the time the switching element is activated due to the stored energy within the magnetic field of the inductive load coming across the switching element terminals in switch OFF condition which may destroy the switching element. To distribute this energy, a Freewheeling diode is used. The Load can be short-circuited at the time the switching element is inactivated. The energy stored in the magnetic field is degenerate like heat.

Table of Content

  • What is a Freewheeling Diode?
  • Basics of Flyback Converters
  • Operation
  • Importance in Inductive Load Circuits
  • Advantages
  • Disadvantages
  • Applications


Similar Reads

What is a Freewheeling Diode?

Freewheeling diode also called a flyback diode, kickback diode, clamp diode, commutating diode, snubber diode, or suppression diode. Freewheeling Diode is used to prevent the high voltage over the switch across the inductive load terminals. This diode is used to protect the circuit from unusual damage due to the sudden decrease in the flow of current in the circuit....

Basics of Flyback Converters

Flyback converters are defined as power converters, that convert AC to DC with galvanic insulation between the inputs and outputs. It stores the energy when the current flows through the circuit and releases the energy when the power is switched off. It uses a mutually coupled inductor and acts as an insulated switching converter for step-down or step-up voltage transformers....

Operation of Freewheeling Diodes

The Freewheeling diode circuit is shown below,...

Importance of Freewheeling Diode in Inductive Load Circuits

In the circuit shown below, the connection of the load Resistor and inductance can be done to the Direct Current source through the switch and diode. When the switch is closed in the circuit for a few seconds, then current flows throughout the load. This current accumulates within the inductor to reach a constant value after some time....

Advantages of Freewheeling Diode

Freewheeling diode increases the load current of various circuits like chopper, inverter and rectifier circuits. Freewheeling diode keeps the silicon-controlled rectifiers from damage in various circuits from the maximum reverse voltage that is produced through the Inductive Load.The input power factor can be increased for converters or phase-controlled rectifiers.It maintains the average output voltage components and ripple components within the output for various circuits.This diode can be operated on a broad range of input voltages.The Flyback converters use very less components compared to the other kinds of Switched-mode power supply....

Disadvantages of Freewheeling Diode

Being careful in choosing the freewheeling diode is essential as incorrect diode ratings may lead to its failure and poor protection.Energy is dissipated as heat in high-power applications. In that situation, a Freewheeling diode may be provided to raise the temperature and there is a requirement for heat sinks or other cooling methods.A few freewheeling diodes may have reverse improvement time after forward bias condition which leads to short period spike.There will be energy losses during the freewheeling phase which takes to slight reduction in overall efficiency as energy stored in the inductor is dissolute as heat in the diode.The short-circuit collapse of the freewheeling diode may lead to potential harm to the Insulated Gate Bipolar Transistors (IGBTs) and other components, as it makes unrestricted high current to the circuit....

Applications of Freewheeling Diode

Freewheeling diode is used in the relay drivers, H-bridge motor drivers, and full-wave rectifiers.Freewheeling diode is used in power circuits to drive the inductive load.It is used to protect the circuits from damage caused by sudden disturbances.To control the strong counter Electromotive force ,the freewheeling diode is used with a relay coil.It makes sure to get a smooth path for current flow during the disturbances in the circuit and prevents harm to sensitive parts.This diode is used to protect the switching devices....

Conclusion

The summary of a freewheeling or flyback diode, its circuit, working, and its applications are discussed above. When designing switching circuits for inductive loads, we need to be responsible for high voltage spikes. Here, switching inductive loads are relays, solenoids, motors and transformers. In the absence of the right circuit protection fixed in the circuit design, the switches would be damaged seriously and may cause circuit failure. To control this, the freewheeling diode is used. Making use of freewheeling diode advantages, used in different applications based on the requirement....

Freewheeling Diode – FAQs

Is Freewheeling diodes used in every inductive circuit?...

Contact Us